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Home My WebLink About03838 - Technical Information Report i I � �� , � � � � � � �, ' � �i i . . � . 11 ' . �O Engineers � � i � Surveyors i _ � � : � � Landscape Architects � �� ' � Fuf I Service Engineering Since � 981 � _ � � � R��`.�'38.3g' � � TECHNICAL INFORMATION REPORT � for THE ENCLAVE AT BRIDLE RIDGE � 14038 156"' Avenue SE Renton,Washington I :R :1. JD � c �YASHJ.1L''jJf �� ^o � 2 ♦ i I � ~� ' �. _;s ,�� ,,\l.��t�..�,�,-�_�\�1��' .I� � jO�;�L � ✓_. / � DRS Project No. 13117 Renton File No. 4 05368 ' � Owner/Applicant PNW Holdings LLC � 9675 SE 36th Street, Suite 105 Mercer Island, WA 98040 Reporf Prepared by I . - � D. R. STRONG Consulting Engineers, Inc. ' 620 7th Avenue Kirkland WA 98033 � (425) 827-3063 Report Issue Date October 2, 2014 � Re ort Revision Date P � May 20, 2015 ( 1 � �2015 D. R.STRONG Consulting Engineers Inc. { � SECTION I PROJECT OVERVIEW The Project is the subdivision of two existing parcels zoned R4 (8.8 ac. total) into 31 single-family residential lots, per the City of Renton's (City) subdivision process. The Tax Parcel Numbers are 1423059122 and 1423059023. The Project location (Site) fronts on the east side of 156th Avenue SE (156t"). The Project will meet the drainage requirements of the City of Renton Amendments to the 2009 King County SurFace Water Design Manual (Manual). The Site is located within the Flow Control Duration Standard Area, matching forested site conditions, matching the 100-year peak discharge (Level 3 Flow Control Standard) and shall be subject to the requirements of Full Drainage Review. PREDEVELOPED SITE CONDITIONS Total existing Site area is approximately 383,127 s.f. (8.795 ac). Total proposed Project area is 390,865 s.f. (8.973 ac), which includes 7,738 s.f. (0.178 ac) for the right-of-way frontage improvements on 156th Avenue SE. The Parcels are currently developed with one single-family residence, out buildings and a gravel driveway. The remainder of the � Site is pasture, scotch broom, and scattered trees. � The 8.795 acres are situated on a slope that discharges runoff into one Threshold Discharge Area (TDA). However, the Site appears to have two Natural Discharge Areas (NDA). See the Level One Downstream Analysis for more information. , For the purpose of hydrologic calculations, the entire Site is modeled as till forest. � DEVELOPED SITE CONDITIONS The applicant has gained approval to create 31 lots with lot sizes ranging from approximately 8,050 s.f. to 12,566 s.f. All existing improvements will be demolished or � removed during plat construction. The 31 single-family residences combined with their ; driveways will create approximately 124,000 s.f. (2.847 ac) of impervious area. The �, proposed 53-foot right of way will be improved with 26 feet of pavement, vertical curb, gutter, 8-foot planter strip and 5-foot sidewalk. The half street frontage improvements on 156th will consist of 22 feet of pavement (6' new), vertical curb, gutter, 8-foot planter i strip and a 5-foot sidewalk. The improvements from right-of ways will add approximately 67,479 s.f. (1.549 ac) of impervious surFace. These areas coupled with Tract A and I bypass impervious areas (0.411 ac.) will result in a total of 4.807 ac of new impervious ��, surfaces. The remainder of the developed Site (4.166 ac) will consist of landscaping and lawns. (See Section IV) Per Appendix C of the Manual, each lot within a new subdivision is required to mitigate 0 for im ervious surface area e ual to 10/o of the lot area. Per Fi ure C.1.3.A Flow P q 9 � Control BMP Flowchart, the Project will utilize Basic Dispersion with the use of splash I blocks. Two splash blocks mitigating a total of 1,400 s.f. of impervious area, will be '� installed with each residence. This shall mitigate for 11.14% to 17.39% of impervious area for each lot, thus accommodating flow control BMP requirements. Splash blocks require a minimum vegetated flowpath of at least 50 feet. If a 50-foot flowpath is unavailable on a given lot, then a 20-foot gravel filled trench shall be utilized for basic C�2015 D. R. STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 1 Technical Information Report City of Renton �� II� . dispersion with a minimum 25-foot vegetated flowpath. See table below for lot area and percent impervious mitigated per lot. ROOF AREA ROUTED TO PERCENT IMPERVIOUS = LOT NO. LOTAREA {S.F.) SPLASH BLOCK (S.F.) MITIGATED �; i 1 8190 1400 17.09 �a� 2 8190 1400 17.09 "; 3 8986 1400 15.58 �`` 4 12566 1400 11.14 �; k�:` 5 8346 1400 16.77 6 8050 1400 17.39 �>,` 7 8052 1400 17.39 8 8052 1400 17.39 9 8052 1400 17.39 . 10 8052 1400 17.39 11 8051 1400 17.39 `�" 12 10479 1400 13.36 �. ' � 13 11170 1400 12.53 14 9266 1400 15.11 15 8398 1400 16.67 16 8625 1400 16.23 17 8050 1400 17.39 18 8050 1400 17.39 19 9237 1400 15.16 20 9252 1400 15.13 21 8050 1400 17.39 22 8050 1400 17.39 23 8050 1400 17.39 24 8683 1400 16.12 25 9533 1400 14.69 � 26 9168 1400 15.27 27 8683 1400 16.12 T 28 8050 1400 17.39 29 8050 1400 17.39 30 8050 1400 17.39 31 9525 1400 14.70 The Project is required to provide Basic Water Quality treatment and Level 3 Flow Control, per the Manual. All surface water runoff from impervious surfaces will be collected and conveyed to a storm detention/water quality pond located in Tract "A". The facility will be sized using 4,000 s.f. of impervious area per lot per section 3.2.2. No flow control credit was taken for the use of splash blocks with regard to facility sizing. No restricted footprint credit is proposed. �:2015 D. R. STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 2 Technical Information Report City of Renton NATURAL DRAINAGE SYSTEM FUNCTIONS The Site topography slopes from the northeast corner of the Site to the southwest. The vegetation consists of pasture, scotch broom, and scattered trees. Site runoff travels southwesterly and sheet flows off the Site to the conveyance system in 156tn A review of the SCS soils map for the area (see Figure 4, Soils) indicates Alderwood gravelly sandy loam with 6 to 15 percent slopes (AgC). Per the Manual, this soil type is classified as "Till" material. The SCS Soil series descriptions follow Figure 4. In evaluating the upstream area, we reviewed King County iMAP aerial topography and imagery and conducted field reconnaissance to evaluate conditions and potential problems. The upstream area for the Site is approximately 3.35 acres, entering the Site in from the northern and eastern property lines. It is prudent to note that these areas are zoned for residential land uses and upon development may generate increased runoff. Each development, however, would be required to collect and convey this increased runoff per the requirements of the Manual. The current land cover of the upstream area appears to be forested and generating negligible runoff. 02015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 3 Technical Information Report City of Renton FIGURE 1 TIR WORKSHEET King County Department of Development and Environmental Services TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND Part 2 PROJECT LOCATION AND PROJECT ENGINEER DESCRIPTION Project Owner: Project Name: PNW Holdings LLC The Enclave at Bridle Ridge Address/Phone: Location: 9675 SE 36�h Street, Suite 105 Township: 23 North Mercer Island, WA 98040 Range: 05 East Section: 14 Project Engineer: Maher A. Joudi, P.E. D. R. STRONG Consulting Engineers Inc. Address/Phone: 620 7th Avenue Kirkland WA 98033 (425) 827-3063 Part 3 TYPE OF PERMIT Part 4 OTHER REVIEWS AND PERMITS APPLICATION � Subdivision ❑ DFW HPA ❑ Shoreline ❑ Short Subdivision Management � Clearing and Grading ❑ COE 404 ❑ Rockery ❑ Commercial ❑ DOE Dam Safety ❑ Structural Vault ❑ Other: ❑ FEMA Floodplain ❑ Other: ❑ COE Wetlands Part 5 SITE COMMUNITY AND DRAINAGE BASIN Community: Newcastle Drainage Basin Lower Cedar River �;2015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 4 Technical Information Report City of Renton Part 6 SITE CHARACTERISTICS ❑River: ❑ Floodplain ❑ Wetland ❑ Stream: ❑ Seeps/Springs ❑ Critical Stream Reach ❑ High Groundwater Table ❑ Depressions/Swales ❑ Groundwater Recharge ❑ Lake: ❑ Other: ❑ Steep Slopes Part 7 SOILS Soil Type: Slopes: Erosion Potential: Erosive Velocities: Alderwood 6-15% Slight Slow (AgC) �Additional Sheets Attached: SCS Map and Soil Description, Figure 4 I Part 8 DEVELOPMENT LIMITATIONS REFERENCE LIMITATION/SITE CONSTRAINT � Level 1 Downstream Analysis None � Geotechnical Engineering Study ❑ Environmentally Sensitive Areas ❑ Level 2 Off-Site Stormwater Analysis � Level I Traffic Impact Analysis ❑ Structural Report ❑ Additional Sheets Attached Part 9 ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION AFTER CONSTRUCTION �Sedimentation Facilities �Stabilize Exposed Surface �Stabilized Construction Entrance �Remove and Restore Temporary ESC Facilities �Perimeter Runoff Control �Clean and Remove All Silt and Debris �Clearing and Grading �Ensure Operation of Permanent Facilities ' Restrictions ❑Flag Limits of SAO and open space preservation �Cover Practices areas �Construction Sequence ❑ Other ❑ Other �2015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 5 Technical Information Report City of Renton Part 10 SURFACE WATER SYSTEM ❑ Grass Lined ❑ Tank ❑ Infiltration Method of Analysis: Channel ❑ Vault ❑ Depression KCRTS � Pipe System ❑ Energy Dissipater ❑ Flow Dispersal Compensation/Mitigatio ❑ Open Channel ❑ Wetland ❑ Waiver n of Eliminated Site ❑ Dry Pond ❑ Stream ❑ Regional Storage � Wet Pond Detention N/A Brief Description of System Operation: Runoff from impervious surfaces will be collected I and conveyed to the detention facility. From there it will be discharged to the conveyance system in 156th Avenue SE. Facility Related Site Limitations: Reference Facility Limitation Part 11 STRUCTURAL ANALYSIS Part 12 EASEMENTS/TRACTS ❑ Cast in Place Vault � Drainage Easement � Retaining Wall ❑ Access Easement � Rockery > 4' High ❑ Native Growth Protection Easement ❑ Structural on Steep Slope � Tracts ❑ Other: ❑ Other: Part 13 SIGNATURE OF PROFESSIONAL ENGINEER I or a civil engineer under my supervision have visited the Site. Actual Site conditions ' as observed were inco orated into this worksheet and the attachments. To the best of my knowledge the i rmation provided here is accurate. � � z-_ ' �-�•l� � Si ned/Date � 02015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 6 Technical Information Report City of Renton FIGURE 2 VICINITY MAP � �; � r9 ;�g aRD FL � SE 1?7Ti�R � ' �tTHSi SE 1�TH P_ � ,�8E Tr PL G� �! SE SR1 ST � ��'P{� SE 1)4TH R i bI 8C STry R � � � � � �1 . '� Wi g�I $ � �'�TM� � a � � � SITE � � � - � � �' � �,�.,o g, � ��T�,� � � � _____ S�,°�'� ►+z+aoa � � � _ a�,naosr � s�++aRo cs `` �' � < � � , ,`�'.' SE 1LiH 91 � � � S" � �� SE S�eTN R �( � `Pr . . �h� �r � � `. � d d #� g \ � � ��,o- se e `;, � $ � I � � 1 � �� ' � � � _ ----- - � -- - -�� --."`�:'��, `. �, (i � g �,.� ' ... � U ��,'� . JR r', ��'f� �!_—„�. � � r '� �� ' --��"1 I � �! Cedar River__ j_� W I " :[ �,�`4�.�, d j � �' _ �' � � �.�� rn r} , � - �r r s�r�aT A f t� � ' �_ � f S s: __ ff__- _ _ _ ---`'� � ��,�'�-. � 5E�q � _-- - -- '----� �y _ - The information included on this map has been compiled by King County staff from a variety of sources and is subject to change without notice.King County makes no representations or warranties,express or implied,as to accuracy, completeness,timeliness,or rights to the use of such information. King County shall not be liable for any general, special, indirect, incidental, or consequential damages including,but not limited to,lost revenues or lost profits resulting from the use or misuse of the information contained on this map.Any sale of this map or information on this map is prohibited except by written permission of King County. 02015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 7 Technical Information Report City of Renton � FIGURE 3 DRAINAGE BASINS, SUBBASINS, AND SITE CHARACTERISTICS �2015 D. R. STRONG Consulting Engineers inc. The Enclave at Bridle Ridge Page 8 Technical Information Report City of Renton a {�,�' � � � = cr `-: " - � � -- '� " =` , w ••; � r� ` �/ � . � �__' .., c W ' �`� '' —'^-�---- �,f - - "_^ r•.:�. 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C _.._. . ,- _ . �... � I NC H = 8O FT. PRO�.£CT ENGlNEER: MAJ f, ' � i .. .. . . . --��j�� , I ��y�� DA7F.• 02.13.14 � -,` . E= PRO,.ECT NO.: 13117 / ``� ` - , • r r ' �\` . 1 . _� c-_ . . R:�2073�1�13177\3\Drowings1Plo£s�fiGures�Figure3_Dreinage_8os;r,s.dwg 2/71/2015 9:09:25 A,L; PST p/ZqµgN� Fl�'aUI�E 3 COPY�4IGHT QQ 2014, D.R. STRONG COhSUL71NG ENGI�=ERS WC. SH£ET• � . FIGURE 4 SOILS F 5a1 ATaF�(ir�Caur;y.4rea,Washington b ,. f� F � � y1.'-3� ��ifF7] S[2-03] �.YIfi7 s!�A i�_'L•."� �'-'_#> rir�a�n a:•Z'3.7h � -- I iF7841N �i i -, L' � ` . 1 (-'- �r� . ..� t :�; :� �� _ c; I:� } - �} ` � SITE Li � - ,�; ;, , ;; ,�,. � ,�� i �_ `, ;i _ t: :. _�{ � �: : :�. _ r<K;, ci � ,�� ; �- � I 3. � � �� . � , �,� . .� �j � . � �z: E� ._� � � ��t � �� , , �:; , , � ; _ -j- , � . E . _ �� :� sn�Sfro � I I I i:'�37A �_�J:] _�iif]] !liyl�:l 'L}�(il s'yF'31 'J��G _4a.",Y:� �lv�.i] 3 3 �; � r�:�:i:i,qia�prail o�n�rir��as x ir�� ,. hte![a3 �� N O �3? 40 61 E20 � � � S � � 10� �0 �300 h4a��Fxcyj�3i�i:VM,Me�4ir C�rrr�d�d�Y1:£.5f Ect,xtl�.:LRMZu�ICf7V��;t 02015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 9 Technical Information Report City of Renton AgC—Alderwood gravelly sandy loam, 6 to 15 percent slopes Map Unit Setting Elevation: 50 to 800 feet Mean annual precipitation: 25 to 60 inches Mean annua!air femperature: 48 to 52 degrees F Frost-free period: 980 to 220 days Map Unit Composition Alderwood and similar soils: 95 percent Minor components: 5 percent Description of Alderwood Setting Landform: Morarnes, til!plains Parent material: Basal til!with some volcanic ash Properties and qualities Slope: 6 to 15 percent Depth to restrictive feature: 24 to 40 inches to dense materia! Drainage c/ass: Moderately well drained Capacity of the most limiting layer to transmit water(Ksat): Very low to moderately low(0.00 to 0.06 in/hr) Depth to water table:About 18 to 37 inches Freguency of flooding: None Frequency of ponding: None Available water capacity.� Very low(about 2.5 inches) Interpretive groups Land capability(nonirrigated): 4s Typical profile I 0 to 12 inches: Gravelly sandy loam 12 to 27 inches: Very grave/ly sandy loam 27 to 60 inches: Very gravelly sandy loam Minor Components Norma Percent of map unit: 1 percent Landform: Depressions Bellingham Percent of map unit: 1 percent Landform: Depressions Seattle Percent of map unit: 1 percent Landform: Depressions Tukwila Percent of map unit: 1 percent Landform: Depressions Shalcar Percent of map unit: ? percent Landform: Depressions 02015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 10 Technical Information Report City of Renton SECTION II CONDITIONS AND REQUIREMENTS SUMMARY The Project must comply with the following Core and Special Requirements: • C.R. #1 — Discharge at the Natural Location: Runoff will discharge at the natural location. • C.R. #2 — Offsite Analysis: Analysis is included in Appendix F. The Analysis describes the Site's runoff patterns in detail. • C.R. #3 — Flow Control: The Project is located in Flow Control Duration Standard Area, matching Forested Conditions for the 100-year peak flow (Level 3 flow control). A detention pond will provide flow control as required. The Project is required to match durations for 50% of the two-year peak flow up to the full 50-year peak flow. Also match developed peak discharge rates to predeveloped peak discharge rates for the 2-year and 10-year and 100-year return periods (KCSWDM, Sec. 1.2.) Furthermore, the Project must meet the Flow Control BMP requirements as specified in Section 1.2.3.3 of the Manual. The Project will utilize basic dispersion via splash blocks to meet the Flow Control BMP requirement. • C.R. #4 — Conveyance System: New pipe systems and ditches/channels are required to be designed with sufficient capacity to convey and contain (at minimum) the 25-year peak flow, assuming developed conditions for onsite tributary areas and existing conditions for any offsite tributary areas. Pipe system structures and ditches/channels may overtop for runofF events that exceed the 25-year design capacity, provided the overflow from a 100-year runoff event does not create or aggravate a "severe flooding problem" or "severe erosion problem" as defined in i C.R. #2. Any overflow occurring onsite for runoff events up to and including the 100- year event must discharge at the natural location for the project Site. In residential subdivisions, such overFlow must be contained within an onsite drainage easement, tract, covenant or public right-of-way. The proposed conveyance system was analyzed using the KCBW program, and is capable of conveying the 100-year peak storm without overtopping any structures or channels. (See Section V) • C.R. #5 — Erosion and Sediment Control: The Project provides the nine minimum ESC measures. • C.R. #6 — Maintenance and Operations: Maintenance of the proposed storm drainage facilities will be the responsibility of the City. An Operation and Maintenance Manual is included in Section X. • C.R. #7 — Financial Guarantees and Liability: Prior to commencing construction, the Applicant must post a drainage facilities restoration and Site stabilization financial guarantee. For any constructed or modified drainage facilities to be maintained and , operated by the City, the Applicant must: 1) Post a drainage defect and maintenance financial guarantee for a period of two years, and 2) Maintain the drainage facilities 02015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 11 Technical Information Report City of Renton during the finro-year period following posting of the drainage defect and maintenance financial guarantee. • C.R. #8 —Water Quality: The Project is located in the Basic Water Quality Treatment area. The combined detention/wetpond facility will accommodate this requirement. • S.R. #1 — Other Adopted Area-Specific Requirements: Not applicable for this Project. • S.R. #2 — Flood Hazard Area Delineation: Not applicable for this Project. • S.R. #3 — Flood Protection Facilities: Not applicable for this Project. • S.R. #4 — Source Control: Not applicable for this Project. • S.R. #5 — Oil Control: Not applicable for this Project. • S.R. #6 —Aquifer Protection Area: Not applicable for this Project. ��2015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 12 Technical Information Report City of Renton SECTION III OFF-SITE ANALYSIS An offsite Level One Downstream Analysis was prepared by D.R. STRONG Consulting Engineers Inc. and is included in Appendix F. �;2015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 13 Technical Information Report City of Renton SECTION IV FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN EXISTING SITE HYDROLOGY (PART A) KCRTS was used to model the peak runoff from the Site. Per Table 3.2.2.b of the Manual the soil type is modeled as "Till" for the Alderwood gravelly sandy loam SCS classification as shown in Figure 4. Soils. The entire Site is modeled as "Forest." Results of the KCRTS analysis are included in this section. Area Breakdown Till Forest 390,865 s.f. 8.973 acres C�2015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 14 Technical Information Report City of Renton PRE-DEVELOPED HOURLY TIME STEP MODELING INPUT: Land cover Entire Site Till forest (ac) 8.973 Till Grass(ac) 0.000 Wetiand (ac) 0.000 Impervious(ac) 0.000 Scale Factor: 1.00 Time Step: Hourly Data Type: Reduced Project location: Seatac Total Area: 8.973 PRE-DEVELOPED HOURLY TIME STEP MODELING OUTPUT: Flow Frequency Analysis Time Series File:predev.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.566 2 2/09/O1 18:00 0.724 1 100. 00 0 . 990 ; 0.154 7 1/06/02 3:00 0.566 2 25.00 0.960 � 0.419 4 2/28/03 3:00 0.435 3 10.00 0.900 0.015 8 3/24/04 20:00 0.419 4 5.00 0.800 0.249 6 1/05/05 8:00 0.366 5 3.00 0.667 0.435 3 1/18/06 21: 00 0.249 6 2.00 0.500 0.366 5 11/24/06 4:00 0.154 7 1.30 0.231 0.724 1 1/09/08 9: 00 0.015 8 1. 10 0.091 ' Computed Peaks 0. 671 50.00 0 . 980 02015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 15 Technical Information Report City of Renton FIGURE 5 PREDEVELOPMENT AREA MAP 02015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 16 Technical information Report City of Renton i I � � � I I 2 I — �_ y � W o � ry � e Q I � LEGEND � � � � I y � � W y � y W � � � � � � ti J � h � � y � �I y � � y � � � � y � � Q � �; I � y � � � ' � � y y � �' �' y �, y W � 8.973 ACRES FORESTED o v 2 Y � I ' �Y �Y �L �L vl �L �Y v �L �L Ji �Y S J � I d Z � '1 �L y v �Y Ji I v �Y �L �L y Jr �L J� n � t�i j m v� W $ a . I '� _ _ .—.- - -- - - -- - -. — .- - - - �Y Jr �L �Y vl Ji �Y v �L �L �L Ji � O v —�L—--s'i——+Y— zc _ v �L Ji �L Ji � �L �L O W � I � �, v �, �, v y �, �, �, ,� �, ,� „ � y ,� „ �, y �, �, PREDE t/EL OPED ONSI TE A REA � ,�, .� .. .i. .� .i. .� .r. .. .. .i, .i. .i. .i. .i. .i. .:� .i. .i. .i. .i TOTAL I I � ,� v �, y y y y �, y �, �, ,;, y ,�, ,:, �. .� y ,�, s � ,�, y SlTE AREA lMPERUIOUS (PA�EMENT) PER�IOUS (TILL FOREST) I ' y �L �L �Y �Y �Y �Y Jr �Y �L v �Y �Y �L �Y J� �L y �Y �Y �Y �L � I � 8.795 AC 0 AC SJ95 AC � Jr Ji J� �Y v W �L �Y �Y Jr �Y �Y v �Y �Y � J� �Y �L Ji J� �L , ' �Y W �L Jr Ji �Y Ji �Y � �Y � �L �L �L �L �Y v y J� �Y v v i 1 PREDE I/EL OPED FRON TA GE IMPRO i/EMEN TS j �Y �L �Y �Y �L J� �Y W �L Ji W Ji Jr � .f� Ji �Y �Y y Ji �Y v ' - �L W y �Y Ji �Y �L v �L � �Y �Y v �L J� �Y v �l! �Y �Y v ., TOTAL i � y � y y y y ,,, y „ y y y ,,, ,� y y y y ,,, y y ., S1TE AREA �MPERI/IOUS (PAUEMENT) PERUIOUS (TILL FOREST) � � y, y P(3ED�1/EL�OPFp F,�401�TAC� II�JPR�I/EI�EN„TS y y y �. �. �- � � 0.178 AC o ac 0.178 AC I - I ' J� �:v �L v �L �L �L J� .v v y �Y �Y �L y �L �L y y Ji Ji v , � y y y y � y y y W y y � � y y � � � y y I,■ � I ' �Y �Y �Y �L �Y J� v �Y �Y �L �Y � �L �L �L �Y �L �Y J� �L �L 'v � . ' �Y �Y Ji �Y �L v �Y �L v �L �Y �L �L �L �L �L �Y �Y �L .L �L Q � � � � � Ji �Y Jr �Y �Y �L v �Y �L �L �Y Ji �Y y W �L �Y W �Y �Y W �L , �Y �Y �Y �Y �L v � �L v y J� J� �Y y J� Ji � �L �Y �L �L � � � II � Ji �Y �Y v �L �L v �Y �L v �L �L y y �L v Ji Ji Ji �Y Ji y � � � —� Q W O I ' —�Y—�l�_ �'_ J' _ v _ �L _�Y _�L Jr �Y �Y Ji �L � �Y Ji � �Y v �L �Y I ' Ji �Y �L �Y �Y y �L �L �L Ji J� �L �Y �Y J� —v —�——.lr— —�.L— --�Y.—�It_ � \ � � . , �Y �L �L J� v v �L �L Jr �Y �L �Y �Y �L �Y �Y �L W �L �L �L � O � Ji �Y �L � J� � v � �L J. W Ji y J� J� �L Ji �L �L �L Ji � �j O� I I � y � y � � �- � �PR�DEI�ELOPEDL 0lVSl T� Af�EA y � �L J� �Y �L .� � o � � � v �L v �L �L Jr �L v y �Y J� �L �Y �L �Y �Y �L Ji y �L Ji �L ' ; � � I ' Ji �L �Y J� �L �L 'v �Y .l� J� �Y J� y y �L Ji �Y �Y �Y �L �Y � O Q II I , �L Ji v y Ji v �L �Y �Y �L J� �Y �Y J� y �Y Ji �Y �Y �Y .Y y LV � , 1 ' .l� �L �L Ji W �Y �:v �L �Y �L J� y �Y J� y �L �L J� v �L �L �L ' � _ � ' ' W W J v W � y J� �L �Y v �Y �L �Y �L �L �L �Y v �Y �Y �Y v J� �L '�� 1 v �Y �L Ji �Y y �L �Y �Y Ji �Y Ji �Y J� � v �Y J� v � �L � ~ � � 1 y J� y y y �L y � y y W �L y y �Y �L �Y �Y y y � �L = � ' v �Y v �L �Y J� �L �Y �Y �Y Ji �Y �Y �Y �Y �L y �L v �Y �L � lI , �L � �L �Y y �Y �Y � �Y �Y �Y �L J� Ji Ji �L v �L �L �L J� �L / ' �'r �Y v v �Y �Y �L �Y �Y �L �Y W J� Ji �Y v y �L �L �Y �L � I ' �L Ji y �Y �Y �Y J� �Y �Y �Y W �L Ji �Y �Y W v �L �L v y �L / , �Y �Y �L 'v Ji �Y �L �Y �Y �L �Y �L �Y Ji �L Jr �Y Ji �Y �L y ' �Y �✓ Ji �Y �L �Y Ji �Y Ji J� Ji Jr �Y J� J� �Y 'v Ji �L �Y �L �Y ' y y y y � y y y y � y y y � y y y y y � y ' �Y v �Y �Y v �Y Ji �Y �Y �L �L v �L �Y �L �Y �L Ji �L Jr �L �, N O RT H GRAPHIC SCALE I ' �Y .L � v J� �L y Ji �Y �Y �L �L �Y �Y �Y Jr W W �Y �L �Y O A O UO �n O �L v �Y �Y �L �L W v Jr .Y �Y �Y �Y �L v �L v Ji �L 4 L I � � ORAf7F0 BY.• pHH _ DESlGNED BY• YLP I 1 INCH — 80 FT. PRo„fcr�crx�n• M.ar . I I I OA 7E 02.13.f4 ,,. PRO.�CT NO.: 13117 /. R:\2013�1�13117�31Drowings\Plots�figures\Figvre_5_�xisting_Ccnditions.dvig 2/1]/2015 9:1I:05 A,1G PST orraw�nrc: F7GURE 5 COPI'31GHT Q 2014, D.R. STRCddG CGNSUL1l�G ENGIN=ERS IPJC. SH££T.• � � DEVELOPED SITE HYDROLOGY (PART B) DEVELOPED SITE AREA HYDROLOGY KCRTS was used to model the developed peak runoff from the Site. The soil types are unchanged from the pre-developed conditions. The portions of the Site within the proposed clearing limits tributary to the proposed detention pond were modeled as "Till Grass" and "Impervious" as appropriate. Results of the KCRTS analysis are included in this section. Area Breakdown Predeveloped Till Forest 390864.6 8.973 Developed I ROW/Frontage Total 84267 1.934 i I m p 67479 1.549 Per 16788 0.385 Lots Total 271006 6.221 I m p 124000 2.847 Per 147006 3.375 Tract A Total 32174 0.739 Imp 16087 0.369 i Per 16087 0.369 Tract B Total 490 0.011 I m p 0 0.000 I Per 490 0.011 Bypass Total 2928 0.067 I m p 1843 0.042 Pe r 1085 0.025 �2015 D.R.STRONG Consulting Engineers Ina The Enclave at Bridle Ridge Page 17 Technical Information Report City of Renton I _ I DEVELOPED HOURLY TIME STEP MODELING INPUT: Land cover Entire Site Till forest(ac) 0.000 Till Grass(ac) 4.141 Wetland (ac) 0.000 Impervious (ac) 4.765 Scale Factor: 1.00 Time Step: Hourly Data Type: Reduced Project location: Seatac Total Area: 8.906 DEVELOPED HOURLY TIME STEP MODELING OUTPUT: Flow Frequency Analysis �ime Series File:rdin.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- =1o�fr Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period _.52 6 2/09/Ol 2:00 3.13 1 100.00 0. 990 1.21 8 1/05/02 16: 00 1.84 2 25.00 0 . 960 1.84 2 2/27/03 7: 00 1.84 3 10.00 0.900 1.26 7 8/26/04 2: 00 1. 62 4 5.00 0.800 1.53 5 10/28/04 16: 00 1.53 5 3. 00 0. 667 1. 62 4 1/18/06 16:00 1.52 6 2.00 0.500 1.84 3 10/26/06 0:00 1.26 7 1.30 0.231 3. 13 1 1/09/08 6:00 1.21 8 1. 10 0 .091 Computed Peaks 2 .70 50. 00 0 . 980 �2015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 18 Technical Information Report City of Renton BYPASS HOURLY TIME STEP MODELING INPUT: Land cover Entire Site Till forest (ac) 0.000 Till Grass(ac) 0.025 Wetland (ac) 0.000 Impervious(ac) 0.042 Scale Factor: 1.00 Time Step: Hourly Data Type: Reduced Project location: Seatac Total Area: 0.067 BYPASS HOURLY TIME STEP MODELING OUTPUT: Flow Frequency Analysis Time Series File:bypass.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob ' (CFS) (CFS) Period I 0.012 6 2/09/Ol 2: 00 0.025 1 100. 00 0. 990 � 0.010 8 1/05/02 16:00 0.016 2 25.00 0. 960 0.015 3 2/27/03 7:00 0.015 3 10. 00 0 . 900 0.011 7 8/26/04 2:00 0.013 4 5. 00 0.800 0.013 4 10/28/04 16:00 0.013 5 3.00 0.667 � 0.013 5 1/18/06 16: 00 0.012 6 2. 00 0.500 0.016 2 10/26/06 0:00 0.011 7 1. 30 0.231 0.025 1 1/09/08 6:00 0.010 8 1.10 0.091 Computed Peaks 0.022 50.00 0 . 980 02015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 19 Technical Information Report City of Renton FIGURE 6 , POST DEVELOPMENT AREA MAP �' 02015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 20 Technical Information Report City of Renton � � � � I I I I w I — I _ �- Z I y � I — �LI � m n 2 2 � 3 ^ O ti � o3 N I I t~i� v�j m 3 N I I ' i I 2 w � � I O O 2 Y b 2 gj � I d 2 � (jn pe � � � vu 2 s o I Q � o i W � I LEGEND � � OAD I I ; ROOF/DRI i/EWA Y 2.847 ACRES IMPER�IOUS I � � LAWN (LOTS) 3.375 PER�IOUS 6 ' � � ROAD/SIDEWALK 1.549 ACRES IMPERI/IOUS � PLANTER 0.385 ACRES PERVIOUS • i 3 30 Zg 27 TRACT A/B 0.369 ACRES lMPERVIOUS I � 26 � LANDSCAPING 0.380 ACRES PERI/IOUS Ij I I' ' ROAD/SIDEW,4LK SYPASS 0.042 ACRES 1MPER liIOUS Q I ; PLAN TER 0.025 A CRES PER 1/IOUS � I � i c� � � � � Io � � ; 20 � 23 J Q � ----I o � z i � i DEI/ELOPED AREA (TO POND) m � ° i � T O T A L IMPER l/IOUS P E R t/I O U S � Q � I � Sl TE AREA (PA VEMEN T) (TILL GRASS) Q � p � i 0 0 0 0 0 �A� � 8.906 AC 4.765 AC 4. 1 41 A C i W O Z � i � � DE t/EL OPED B YPA SS AREA � � 'w � , I � TO TAL IMPER t//OUS PER l/IDUS � � V I , S I T E A R E A (P A l/E M E N T) (T I L L G R A S S) W W � 17 ~ � I 9 �4 0.067 AC 0.042 AC 0.025 AC T � �� ~ / / I , � / T C " ' 93 2 ORM RAJN N O RT H ' � � GRAPHIC SCALE 0 40 80 120 I = i= ORAf7ED BY• OHH — - DESICNED BY• YLP I � INCH — 8O FT. PRWECT£NGIN£ER: MAJ I I DATE• 0213.14 I PR0I.ECT NO.: 13117 /' ' . . . R:�2073\1`13177\3�D-a.vi.nys\Plo!s\figures\Fig�:�e_6_Frcpcsed_Conditior,s.dwg 2/i1/2015 9:13:57 A,44 PSr DRAW7N� FlGURf 6 �� CGPYRIGF.T Q 2G'.4, D.4. S-P,��JG CONSL'�L7'•JG ENGR.E=RS INC. SNFFf.• T � PERFORMANCE STANDARDS (PART C) The Project is required to adhere to Level 3 Flow Control criteria. The Level 3 performance criteria requires that the developed condition's durations must match the predeveloped durations ranging from 50% of the two-year peak flow up to the full 50- year peak flow and also match developed peak discharge rates to predeveloped peak discharge rates for the 2-year, 10-year and 100-year return periods (KCSWDM, Sec. 1.2). The Basic Water Quality Treatment goal is to remove 80% of TSS for flows or volumes up to and including the WQ design flow or volume. Conveyance criteria for the Project require that all new pipes be designed to convey and contain (at minimum) the 25-year peak flow. FLOW CONTROL SYSTEM (PART D) � The Site will utilize a detention pond meeting the Level 3 Flow Control Criteria. The King County Runoff Time Series (KCRTS) software was used to size the detention facility. The detention pond design information is included in this section. FLOW CONTROL BMP SELECTION Subdivision projects are required to mitigate for impervious surface equal to a minimum of 10% of each lot area by use of Flow Control Best Management Practices (BMP's). Projects are required to first analyze the feasibility of dispersal and infiltration before choosing another method. The Site will utilize basic dispersion with the use of splash blocks. Two splash blocks mitigating a total of 1,400 s.f. of impervious area, will be installed with each residence. This shall mitigate for 11.14% to 17.39% of impervious area for each lot, thus accommodating flow control BMP requirements. Splash blocks require a minimum vegetated flowpath of at least 50 feet. If a 50-foot flowpath is unavailable on a given lot, then a 20-foot gravel filled trench shall be utilized for basic dispersion with a minimum 25-foot vegetated flowpath. �2015 D. R STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 21 Technical Information Report City of Renton FLOW CONTROL FACILITY DESIGN OUTPUT Retention/Detention Facility Type of Facility: Detention Pond Side Slope: 2.35 H: 1V Pond Bottom Length: 160.25 ft Pond Bottom Width: 80.00 ft Pond Bottom Area: 12820. sq. ft Top Area at 1 ft. FB: 21794 . sq. ft 0.500 acres Effective Storage Depth: 6. 00 ft Stage 0 Elevation: 371.00 ft Storage Volume: 98806. cu. ft 2.268 ac-ft Riser Head: 6.00 ft Riser Diameter: 18.00 inches Number of orifices: 3 Full Head Pipe Orifice # Height Diameter Discharge Diameter (ft) (in) (CFS) (in) 1 0.00 1.52 0.153 2 3.80 2 .28 0.209 6.0 3 3. 98 2 . 35 0.213 6.0 Top Notch Weir: None Outflow Ratirg Curve: None Stage Eleva�icn Storage �ischarce Perco,_at--on Su== Area (ft) (ft) (cu. ft) (ac-ft) (cfs) (cfs) (sq. ft) 0.00 371.00 0. 0.000 0.000 0.00 12820. 0.02 371.02 257. 0.006 O.008 0.00 12843. 0.03 371.03 385. 0.009 0.011 0.00 12854. 0.05 371.05 642. 0.015 0.014 0.00 12876. 0.06 371.06 771. 0.018 0.016 0.00 12888. 0.08 371.08 1029. 0.024 0.018 0.00 12910. 0.10 371.10 1288. 0.030 0.019 0.00 12933. 0.11 371.11 1417. 0.033 0.021 0.00 12944. 0.13 371.13 1676. 0.038 0.022 0.00 12967. 0.24 371.24 3109. 0.071 0.031 0.00 13092. 0.36 371.36 4689. 0.108 0.038 0.00 13229. 0.48 371.48 6284. 0.144 0.043 0.00 13366. 0.60 371.60 7897. 0.181 0.048 0.00 13505. 0.71 371.71 9389. 0.216 0.053 0.00 13632. 0.83 371.83 11033. 0.253 0.057 0.00 13771. 0.95 371.95 12694. 0.291 0.061 0.00 13911. 1.07 372.07 14372. 0.330 0.065 0.00 14052. 1.19 372.19 16067. 0.369 0.068 0.00 14193. 1.30 372.30 17635. 0.405 0.072 0.00 14323. 1.42 372.42 19362. 0.444 0.075 0.00 14466. � 1.54 372.54 21107. 0.485 0.078 0.00 14609. 1.66 372.66 22869. 0.525 0.081 0.00 14753. 1.77 372.77 24499. 0.562 0.083 0.00 14885. 1.89 372.89 26294. 0.604 0.086 0.00 15030. 2.01 373.01 28106. 0.645 0.089 0.00 15176. 02015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 22 Technical Information Report City of Renton 2.13 373.13 29936. 0.687 0.091 0.00 15322. 2.24 373.24 31629. 0.726 0.094 0.00 15457. 2.36 373.36 33492. 0.769 0.096 0.00 15604. 2.48 373.48 35374. 0.812 0.099 0.00 15752. 2.60 373.60 37273. 0.856 0.101 0.00 15901. 2.71 373.71 39029. 0.896 0.103 0.00 16038. 2.83 373.83 40963. 0.940 0.105 0.00 16188. 2.95 373.95 42915. 0.985 0.108 0.00 16339. 3.07 374.07 44884. 1.030 0.110 0.00 16490. 3.19 374.19 46872. 1.076 0.112 0.00 16642. 3.30 374.30 48710. 1.118 0.114 0.00 16781. 3_42 374.42 50733. 1.165 0.116 0_00 16935. 3.54 374.54 52775. 1.212 0.118 0.00 17088. 3.66 374.66 54835. 1.259 0.120 0.00 17243. 3.77 374.77 56739. 1.303 0.122 0.00 17385. 3.80 374.80 57261. 1.315 0.122 0.00 17424. 3.82 374.82 57610. 1.323 0.124 0.00 17449. 3.85 374.85 58134. 1.335 0.128 0.00 17488. 3.87 374.87 58484. 1.343 0.135 0.00 17514. 3.90 374.90 59010. 1.355 0.145 0.00 17553. 3.92 374.92 59361. 1.363 0.157 0.00 17579. 3.94 374.94 59713. 1.371 0.171 0.00 17605. 3.97 374.97 60242. 1.383 0.182 0.00 17644. 3.98 374.98 60419. 1.387 0.185 0.00 17657. 4.00 375.00 60772. 1.395 0.191 0.00 17683. 4.03 375.03 61303. 1.407 0.199 0.00 17723. 4.05 375.05 61658. 1.415 0.210 0.00 17749. 4.08 375.08 62191. 1.428 0.223 0.00 17788. 4.10 375.10 62597. 1.436 0.239 0.00 17814. 4.13 375.13 63082. 1.448 0.257 0.00 17853. 4.15 375.15 63439. 1.456 0.273 0.00 17880. 4.18 375.18 63976. 1.469 0.281 0.00 17919. 4.29 375.29 65955. 1.514 0.313 0.00 18063. 4.41 375.41 68132. 1.564 0.340 0.00 18222. 4.53 375.53 70328. 1.615 0.365 0.00 18381. 4.65 375.65 72544. 1.665 0.387 0.00 18540. 4.76 375.76 74591. 1.712 0.408 0.00 18687. 4.88 375.88 76843. 1.764 0.427 0.00 18848. 5.00 376.00 79115. 1.816 0.446 0.00 19010. 5.12 376.12 81406. 1.869 0.463 0.00 19172. 5.23 376.23 83523. 1.917 0.480 0.00 19321. 5.35 376.35 85851. 1.971 0.496 0.00 19484. 5.47 376.47 88199. 2.025 0.512 0.00 19648. 5.59 376.59 90566. 2.079 0.527 0.00 19813. 5.71 376.71 92954. 2.134 0.541 0.00 19978. 5.82 376.82 95160. 2.185 0.555 0.00 20130. 5. 94 376.94 97585. 2.240 0.569 0.00 20296. 6.00 377.00 98806. 2.268 0.576 0.00 20380. 6.10 377.10 100851. 2.315 1.050 0.00 20519. 6.20 377.20 102909. 2.362 1.900 0.00 20659. 6.30 377.30 104982. 2.410 3.010 0.00 20799. 6.40 377.40 107069. 2.458 4.310 0.00 20940. 6.50 377.50 109170. 2.506 5.790 0.00 21081. 6.60 377.60 111286. 2.555 7.230 0.00 21223. 0.70 377.70 113415. 2.604 7.770 0.00 21365. 6.80 377.80 115559. 2.653 8.270 0.00 21507. 6.90 377.90 117716. 2.702 8.740 0.00 21650. 7.00 378.00 119889. 2.752 9.190 0.00 21794. 7.10 378.10 122075. 2.802 9.610 0.00 21938. 7.20 378.20 124276. 2.853 10.020 0.00 22082. 02015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 23 Technical Information Report City of Renton 7.30 378.30 126492. 2.904 10.410 0.�0 22227. 7.40 378.40 128722. 2.9�5 10.780 0.00 22372. 7.50 378.50 130966. 3.007 11.150 0.00 22517. 7.60 378.60 133225. 3.058 11.500 0.00 22663. 7.70 378.70 135499. 3.111 11.840 0.00 22810. 7.80 378.80 137787. 3.163 12.170 0.00 22957. 7.90 378.90 140090. 3.216 12.490 0.00 23104. 8.00 379.00 142408. 3.269 12.800 0.00 23252. Hyd Inflow Outflow Peak Storage Stage Elev (Cu-Ft) (Ac-Ft) 1 3. 00 0.72 6.03 377.03 99419. 2 .282 2 1.45 0.51 5.48 376. 48 88399. 2 .029 3 1.75 0.42 4.86 375.86 76441. 1.755 4 1. 67 0.42 4.82 375. 82 75753. 1.739 5 1.53 0.28 4. 19 375. 19 64191. 1.474 6 1 . 40 0.15 3. 91 374 . 91 59120. 1.357 7 1 . 12 0.11 3.31 374 . 31 48933. 1 . 123 8 1. 15 0.09 2. 10 373. 10 29455. 0. 670 Hyd R/D Facility Tributary Reservoir POC Outflo�v Outflow Inflow Inflow Target Calc 1 0.72 0.02 ******** 0.72 0.72 ' ' 2 0.51 0.01 ******** ******* 0.52 3 0. 42 0.01 ******** ******* 0. 43 4 0. 42 0.02 ******** ******* 0. 42 5 0.28 0.01 ******** ******* 0.29 6 0. 15 0.01 ******** ******* 0. 15 7 0. 11 0.01 ******** ******* 0. 12 8 0.09 0.01 ******** ******* 0. 09 ---------------------------------- Route Time Series through Facility Inflow Time Series File:rdin.tsf Outflow Time Series File:rdout POC !ime Series File:dsout Inflosrr/Outflo�ra Analysis Peak Inflow Discharge: 3.00 CFS at 6:00 on Jan 9 in Year 8 , Peak Outflow Discharge: 0.718 CFS at 11:00 on Jan 9 in Year 8 Peak Reservoir Stage: 6.03 Ft Peak Reservoir Elev: 377 .03 Ft Peak Reservoir Storage: 99419. Cu-Ft . 2 .282 AC-Ft Add Time Series:bypass.tsf Peak Summed Discharge: 0. 724 CFS at 11 : 00 on Jan 9 in Year 8 Point of Compliance File:dsout.tsf Flow Frequency Analysis Time Series File:rdout.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS} (CFS) (ft) Period 02015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 24 Technicai Information Report City of Renton 0.513 2 2/09/Ol 20:00 0.718 6.03 1 100.00 0. 990 I 0. 114 7 1/07/02 5: 00 0. 513 5. 48 2 25.00 0. 960 ` 0.424 3 3/06/03 22: 00 0.424 4. 86 3 10.00 0. 900 ' 0.090 8 8/26/04 8:00 0.418 4.82 4 5.00 0.800 0.149 6 1/08/05 3:00 0.284 4. 19 5 3.00 0. 667 0.284 5 1/19/06 1:00 0. 149 3. 91 6 2.00 0.500 0.418 4 11/24/06 8:00 0.114 3.31 7 1.30 0.231 0.718 1 1/09/08 11:00 0.090 2. 10 8 1.10 0.091 Computed Peaks 0. 650 6. 02 50. 00 0 . 980 �� Flow Frequency Analysis �� Time Series File:dsout.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.517 2 2/09/Ol 20: 00 0.724 1 100. 00 0 . 990 0. 115 7 1/07/02 2: 00 0.517 2 25. 00 0 . 960 0. 426 3 3/06/03 22:00 0. 426 3 10. 00 0 .900 0.092 8 8/26/04 2:00 0. 421 4 5.00 0.800 0.150 6 1/08/05 3:00 0.286 5 3.00 0.667 0.286 5 1/19/06 1:00 0. 150 6 2.00 0.500 0.421 4 11/24/06 8:00 0. 115 7 1.30 0.231 0.724 1 1/09/08 11:00 0.092 8 1. 10 0.091 Computed Peaks 0. 655 50. 00 0. 980 Flow Duration from Time Series File:rdout.tsf Cutoff Count Frequency CDF Exceedence_Probability CFS ° ° ° o a o 0.007 33321 54.340 54.340 45. 660 0. 457E+00 0.022 5984 9.759 64.098 35. 902 0.359E+00 0.036 5280 8.611 72.709 27.291 0.273E+00 0.051 4910 8.007 80.716 19.284 0. 193E+00 0.065 4127 6.730 87.446 12 .554 0. 126E+00 0.079 2989 4.874 92.321 7 . 679 0.768E-01 0.094 1762 2.873 95 . 194 4.806 0. 481E-01 0.108 1335 2.177 97 .371 2. 629 0.263E-01 0.123 1183 1.929 99.300 0.700 0.700E-02 0.137 72 0.117 99.418 0.582 0.582E-02 0.152 42 0.068 99.486 0.514 0.514E-02 0. 166 24 0.039 99.525 0.475 0. 475E-02 0. 180 25 0.041 99.566 0.434 0. 434E-02 0.195 36 0.059 99. 625 0.375 0. 375E-02 0.209 16 0.026 99. 651 0.349 0.349E-02 0.224 18 0.029 99. 680 0.320 0.320E-02 0.238 9 0.015 99. 695 0.305 0.305E-02 0.253 17 0.028 99.723 0.277 0.277E-02 0.267 10 0.016 99.739 0.261 0.261E-02 0.281 13 0.021 99.760 0.240 0.240E-02 0.296 22 0.036 99.796 0.204 0.204E-02 0.310 12 0.020 99.816 0.184 0.184E-02 0.325 13 0.021 99.837 0.163 0. 163E-02 0. 339 10 0.016 99.853 0.147 0. 147E-02 0.354 12 0.020 99.873 0.127 0. 127E-02 C;2015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 25 Technical Information Report City of Renton 0.368 7 0.011 99.884 0. 116 0.116E-02 0.382 9 0.015 99.899 0.101 O. 101E-02 0.397 7 0.011 99. 910 0.090 0. 897E-03 0.411 9 0.015 99. 925 0.075 0.750E-03 0.426 15 0.024 99. 949 0. 051 0.506E-03 0. 440 9 0.015 99. 964 0.036 0.359E-03 0. 455 4 0.007 99. 971 0.029 0.294E-03 0. 469 3 0.005 99. 976 0.024 0.245E-03 0. 483 4 0.007 99. 982 0.018 0. 179E-03 0.498 4 0.007 99. 989 0.011 0. 114E-03 0.512 5 0.008 99. 997 0.003 0.326E-04 Flow Duration from Time Series File:dsout.tsf Cutoff Count Frequency CDF Exceedence_Probability CFS o °s % 0.007 33305 54 .313 54 .313 45. 687 0. 457E+00 0.022 6006 9.795 64. 108 35. 892 0.359E+00 0.036 5276 8. 604 72.712 27.288 0.273E+00 0. 051 4865 7. 934 80. 646 19.354 0. 194E+00 0.065 4197 6.844 87. 490 12.510 0.125E+00 0.080 2937 4.790 92.280 7.720 0.772E-01 0.094 1797 2.931 95.210 4.790 0. 479E-01 0.109 1328 2.166 97.376 2 . 624 0.262E-01 0.124 1162 1.895 99.271 0.729 0.729E-02 0.138 91 0.148 99. 419 0.581 0.581E-02 0. 153 41 0.067 99.486 0.514 0.514E-02 0. 167 24 0.039 99.525 0.475 0.475E-02 0. 182 28 0.046 99.571 0.429 0. 429E-02 0.196 30 0.049 99. 620 0.380 0.380E-02 0.211 19 0.031 99. 651 0.349 0.349E-02 0.225 17 0.028 99. 679 0.321 0.321E-02 0.240 11 0.018 99. 697 0.303 0.303E-02 0.254 16 0.026 99.723 0.277 0.277E-02 0.269 9 0.015 99.737 0.263 0.263E-02 0.283 13 0.021 99.759 0.241 0.241E-02 0.298 23 0.038 99.796 0.204 0.204E-02 0.312 11 0.018 99.814 0.186 0. 186E-02 0.327 13 0.021 99.835 0. 165 0. 165E-02 0.341 11 0.018 99.853 0. 147 0. 147E-02 0.356 11 0.018 99.871 0. 129 0. 129E-02 0.370 7 0.011 99.883 0. 117 0. 117E-02 0.385 9 0.015 99.897 0. 103 0. 103E-02 ' 0.399 7 0.011 99. 909 0. 091 0. 913E-03 ' 0. 414 11 0.018 99. 927 0.073 0.734E-03 0. 428 15 0.024 99. 951 0.049 0. 489E-03 I 0.443 6 0.010 99. 961 0.039 0.391E-03 0. 458 6 0.010 99.971 0.029 0.294E-03 ' 0. 472 4 0.007 99.977 0.023 0.228E-03 0. 487 3 0.005 99.982 0.018 0. 179E-03 0.501 4 0.007 99. 989 0.011 0. 114E-03 0.516 5 0.008 99. 997 0. 003 0.326E-04 Duration Comparison Anaylsis Base File: predev.tsf New File: dsout.tsf 02015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 26 Technical Information Report City of Renton Cutoff Units: Discharge in CFS -----Fraction of Time----- ---------Check of Tolerance------- Cutoff Base New %Change Probability Base New oChange 0.124 � 0. 95E-02 0.71E-02 -25.6 � 0. 95E-02 0. 124 0. 121 -2. 4 0. 158 � 0. 63E-02 0.50E-02 -21.4 � 0. 63E-02 0.158 0. 129 -18.3 0.192 � 0. 50E-02 0.39E-02 -20.4 � 0.50E-02 0. 192 0. 158 -17 .5 0.226 � 0.37E-02 0.32E-02 -14. 1 � 0.37E-02 0.226 0. 199 -11 . 9 0.260 � 0.28E-02 0.27E-02 -6.3 � 0.28E-02 0.260 0.247 -4 . 9 0.294 � 0.22E-02 0.21E-02 -5. 1 � 0.22E-02 0.294 0.290 -1. 4 0.328 � 0. 15E-02 0. 16E-02 11. 1 � 0. 15E-02 0.328 0.342 4.2 0.362 � 0. 10E-02 0.12E-02 21 . 0 � O.10E-02 0. 362 0.387 7 .0 0.396 � 0. 62E-03 0. 91E-03 47 .4 � 0. 62E-03 0. 396 0.421 6.3 0.430 � 0.34E-03 0.49E-03 42. 9 I 0.34E-03 0. 430 0. 447 4 .0 0.464 � 0.21E-03 0.28E-03 30.8 � 0.21E-03 0.464 0. 483 4 . 1 0. 497 � 0. 16E-03 0. 13E-03 -20.0 � 0. 16E-03 0. 497 0. 492 -1 . 1 0.531 � 0. 11E-03 O.00E+00 -100.0 � 0. 11E-03 0.531 0.504 -5 .2 0.565 I 0. 16E-04 O.00E+00 -100.0 � 0.16E-04 0.565 0.517 -8 . 6 Maximum positive excursion = 0.036 cfs ( 9. 80) occurring at 0.368 cfs on the Base Data:predev.tsf and at 0 .404 cfs on the New Data:dsout.tsf Maximum negative excursion = 0. 032 cfs (-18.7%) occurring at 0.172 cfs on the Base Data:predev.tsf and at 0.140 cfs on the New Data:dsout.tsf PEAK PLOT Retum Period 2 5 10 2D 50 100 �� c rccui.pks in Sez-Tzc • Csout.pks � predev.pk.s � • rtlin.pks • • • � � s • • 70° - LL R ` v o 0 m � rn � L C 000 ❑ � ♦ 00 ♦ 10� ♦ 10-� 1 2 5 10 20 30 40 50 6D 70 80 90 95 98 99 Cumuiative Proba5i5ty G2015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 27 Technical Information Report City of Renton DURATION ANALYSIS � 0 �d�ut.d�� . dsout_tlur ♦ target.dur o � o R ��__�`__1 N � O N � LL O m �� f3i L f`J � Q O ,� N � o coo �� 00 ��. 0 0 0 0 ♦ i i 70 5 10 10 3 70 2 10 � 10° � Probabifiy Exceedence � �2015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 28 Technical Information Report City of Renton WATER QUALITY TREATMENT SYSTEM (PART E) The Project is located in the Basic Water Quality Treatment area. The treatment goal is 80% removal of total suspend solids for a typical rainfall year, assuming typical pollutant concentrations in urban runoff. A combined detention/water quality pond will accommodate this requirement. Rainfall(R)of the mean annual storm= 0.47 in. From KCSWDM Fig.6.4.t.A Area of impen.ious surface(Ai)= 207,566 s.f. ' Area of till soil co�ered with till grass(Atg)= 180,371 s.f. Area of till soil corered with till forest(At�= 0 s.f. Area of outwash soil coeered with grass or forest(Ao)= 0 s.f. Volume factor(�= 3 N.�A From KCSLVDPd Sec. 6.4.1.1 Calculations Units Notes Volume of runoff from mean annual stortn(Vr)= 9082.822 c.f. =(0.9Ai+0.25Atg+0.10Atf+0.01Ao)*R/12 Minimum Wetpool wlume required(Vb)= 27,248 c.f. =f`Vr The provided water quality volume is 35,071 c.f. See Figure 7 for details. 02015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 29 Technical Information Report City of Renton FIGURE 7 DETENTION & WATER QUALITY FACILITY DETAILS 02015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 30 Technical Information Report City of Renton � ro ��T, THE'4E11%CLA�VE AHT BR%DL E R%DGE ,�. A s71.10./4 Z1.7�R N ��iriy c n3u p (�aeusE Ear�aaaccuD Ml�' Q . ' ' ' . . K1P12 EJ72N(�N p . . . . . .1 IX IA'C]P E J711<�WT 75-0 Q . . ' . � '�, 12'IEJ73Df(IYJOVT � ..� .-� �� . . ` ri , �•� � � sF acr,u.srrrr cre 3. � J ,7gp . . 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I "' 6'RKID �I .i ��' . ••�••�,•v. �'��;�f '.,, 6 � P£RFqPA1E0 PIPE =�� ..�., ::�s f o � _ ..�rm CIWNLINRFQICE '� O � .�V TYPE31AMD4 ', `��—��IIASHm ROCK � �'�� C °k' STIUO4RD RAN 4111.1p02 � a a � �i� � 71'YN.! 21' w INTERCEPTOR TRENCH CROSS SECAON � Y N�s � RECOMMENDED FOR APPOVAL / BY: Date: - BY: Date: , BY: Date: BY Date: R� �0�. ��" ' ��'�'o� 1 qIY COI�EMS 17.iS1{ IW 0213.13 YAI =� z an�s �w os.+�•+s �w ��s Ho�m ""°�""' :: � CI TY OF TME ENCLAVE AT BRIDLE RIDGE ��o.os.�+ ? �� Y '"^" D.R.STRONG nr � ; °`a"a 811 °ip �� , � � `/\� CONSULTlNG ENGINEERS �-� � R r N TO N STORM DRAINAGE DEfAILS Ul�itiaslMtdar¢andLoeedanCenla '� 4��/`u`� '� ��,\ �1 � ��3�� "`yN L� �n� 'Ic�ning/Buildirg/Fu51ic Wo�ks Dept. ��g u (D.AAT,FD,ORWN `� i�AL F'� t^ � �—� exmm+�vEnvE�w�.pso.0 VD. RE`+'ISION EY �E A�FR U14005368 � -r oszsaz�ao�F�zxezssev iiw �•am•�• `��ta �29 � DRS PROJECT N0. 13117 A-N N N N A A SECTION V CONVEYANCE SYSTEM ANALYSIS AND DESIGN Per Core Requirement #4 of the KCSWDM, the conveyance system must be analyzed and designed for existing tributary and developed onsite runoff from the proposed project. Pipe systems shall be designed to convey the 100-year design storm. The Rational Method was used to calculate the Q-Ratio for each pipe node. A conveyance system consisting primarily of pipes and catch basins has been designed for the Project. Onsite runoff will be collected by the multiple catch basins. Pipes are typically twelve- and eighteen-inch diameter LCPE material. The pipes will have a minimum slope of 0.50%. The pond primary overflow riser is designed to convey the 100-year peak storm (design storm), based on the KCRTS 15-minute time series for developed, undetained conditions on site. This is calculated at 7.71 cfs. The results of the 15-minute KCRTS time series, overFlow riser analysis, and KCBW Calculations are included in this Section. DEVELOPED 15-MINUTE TIME SERIES Modeling input Land cover Entire Site Till forest(ac) 0.000 Till Grass(ac) 4.141 Wetland (ac) 0.000 Impervious(ac) 4.765 Scale Factor: 1.00 Time Step: 15-Min Data Type: Reduced Project location: Seatac Tota I Are a: 8.906 Table 4 Developed 15-Min KCRTS Modeling Input 02015 D. R. STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 31 Technical Information Report City of Renton Modeling results Developed 15-Min Flow Frequency Analysis Time Series File:15-min.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 2.27 6 8/27/O1 18:00 7 .71 1 100.00 0 . 990 1. 68 8 1/05/02 15:00 5.20 2 25.00 0 . 960 5.20 2 12/08/02 17: 15 3.24 3 10. 00 0. 900 1. 83 7 8/23/04 14:30 3.21 4 5.00 0. 800 3.24 3 11/17/04 5: 00 2 .81 5 3.00 0. 667 2.81 5 10/27/05 10:45 2 .27 6 2.00 0.500 3.21 4 10/25/06 22: 45 1.83 7 1.30 0.231 7.71 1 1/09/08 6:30 1. 68 8 1. 10 0. 091 Co�nputed Peaks 6.87 50. 00 0 . 980 FLOW CONTROL PRIMARY OVERFLOW Using standard orifice equation to determine stand pipe diameter in control structure Ref. KCSWDM '09 Figure 5.3.4.H Q�oo = 100-Year Peak Storm calculated using KCRTS 15-Minute Time Steps Q�oo= 7.71 cfs HMAX= Maximum available head in feet measured from crest of weir HM�= 1 ft. D= Riser Diameter D = �Q�oo/(3.782 * Htiu,x.s��o.s D = 1.43 ft. (min. diameter) round up to nearest standard pipe diameter use D = 18 in. or 1.5 ft. Calculate actual height above the weir expected during the 100-year peak storm H = Actual head above weir achieved with Q�oo H = (Q�oo/(9.739 * D))^0.67 H = 0.65 ft. 02015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 32 Technical Information Report City of Renton JAILHOUSE SECONDARY OVERFLOW Using standard weir equation to determine length of window opening in control structure Ref. KCSWDM '09 Figure 5.3.4.E D= Control structure diameter D= 60 in. Q�oo= 100-Year Peak Storm calculated using KCRTS 15-Minute Time Steps Q�oo= 7.71 cfs HM,�= Head above weir achieved with Q,00 HM�= 0.65 ft. P= Height of overflow above outlet invert elevation P= 6.00 ft. c= Constant c= 3.27+0.4'`HM�/P C= 3.31 ft. L= Arc length of the jailhouse window as necessary but not to exceed 50% of the control structure's internal circumference L= �Q�oo��*HMAX1.5)��.0.2"HMAx L= 4.57 ft. (min. length) C= Control Structure Circumference C= 16 ft. Calculate corrected L due to vertical bars in window. L�� adjusted arc length of the jail-house window , L��= L+0.083"(L/0.33) �-ad]= 5.72 ft. BIRDCAGE EMERGENCY OVERFLOW Using sharp crested weir equation to determine stand pipe diameter in control structure Ref. KCSWDM '09 Figure 5.3.4.E Q�oo= 100-Year Peak Storm calculated using KCRTS 15-Minute Time Steps Q�oo= 7.71 cfs P= Height of primary overflow above outlet invert elevation P= 6.65 ft. D= Control structure diameter D= 60 in. L= Control structure circumference L= 15.71 ft. C= 3.27+0.4H/P (ft) use... Q�oa= 3.27+0.4H/P(L-0.2H)H^1.5 H= Emergency overflow water surface elevation H= 0.28 ft. �2015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 33 Technical Information Report City of Renton BACKWATER ANALYSIS Storm Water Runoff Variables: A= Total of Subasin and 1'ributary Areas C= Runoff Cocfficient (the anticipatcd proportion of rainfall volwne that runs off thc area)see 2009 KCSWM Table 3.2.1 A C� Composite RunofP Coefficicnt Cc S(C�*A�)��`.rm� "I'� Time of Concentration (Typically 6.3 minutcs which is the minimwn value used in calculations) R= desigi rcturn frequency i�;= Unit pcalc rainfa]]intensity factor �ii-� ��R�� c�^l'UR� a12,U�t= coefCicients from 2009 KCSWM Table 3.2.1.B used to adjust thc cquation for the design storm 1R= Aeak rainfall intensi�y 1'actor for a storm of return frequency'R' *• lii— 1'R 'ii P�t total precipitalion (inches)for the 24-hour storm cvent for the�iven frequcncy. See Issopluvia]Maps in 2009 KCSWM Figures 3.2.1 QR peak flow(cfs)for a storm of return frequency R' = C *i *A Qx c a Thc Q-1Zatio describes the ratio of the tributary flowto the main upstream flow. R=_"year storm aa= 2.6 I b,i= 0.63 PR=—inches Conveyance Systcm Variables: d= pipe diameter i1= Manning's Number 1= lenSLh of pipc c�2015 D. R.STRONG Consulting Engineers Ina The Enclave at Bridle Ridge Page 34 Technical Information Report City of Renton Pipe Structures Subasins� A A C CC Tc iR IR oR SQR Q- d Material n I Slope invert invert over- Q V Bend CB Tributaries subasin Ratio in out Flow Full Full Dia elev. Flow Flow FROM CB To CB sf Ac Ac Min. cfs cfs in ft % ft ft ft cfs fps CB#10 TO INLET 1 10 10 9 10 44153 1.01 0.58 6.3 0.82 3.27 1.92 1.92 0.00 12 LCPE 0.012 24 5.51 396.55 395.21 399.55 9.08 11.56 0 2 9 9 8 9 17555 0.40 0.67 6.3 0.82 3.27 0.89 2.80 0.46 12 LCPE 0.012 184 2.60 395.21 390.43 399.55 6.24 7.95 90 2 RUN 108-8 9182 0.21 0.90 8 8 7 8 18978 0.44 0.68 8 8 7 8 28160 0.65 0.75 6.3 0.82 3.27 1.59 4.39 0.57 12 LCPE 0.012 78 0.75 390.43 389.84 394.14 3.36 4.27 0 2 7 7 6 7 576 0.01 0.90 6.3 0.82 3.27 0.04 4.43 0.01 12 LCPE 0.012 51 1.84 389.84 388.9 394.84 5.25 6.69 46 2 6 6 5 6 2238 0.05 0.90 6.3 0.82 3.27 0.15 4.58 0.03 12 LCPE 0.012 187 4.03 388.90 381.36 392.90 7.77 9.89 46 2 5 5 4 5 6747 0.15 0.90 6.3 0.82 3.27 0.46 5.04 0.10 12 LCPE 0.012 38 8.24 381.36 378.19 364.40 11.11 14.15 47 2 RUN 30-4 26915 0.62 0.54 4 4 3 4 2004 0.05 0.90 4 4 3 4 28919 0.66 0.56 6.3 0.82 3.27 1.23 6.27 0.24 18 LCPE 0.012 27 0.77 377.69 377.48 382.66 9.99 5.65 48 2 RUN 103-3 2052 0.05 0.90 3 3 2 3 519 0.01 0.90 3 3 2 3 2571 0.06 0.90 6.3 0.82 3.27 0.17 6.44 0.03 18 LCPE 0.012 82 1.07 377.48 376.6 382.48 11.82 6.69 90 2 RUN 102-2 40763 0.94 0.62 2 2 1 2 41321 0.95 0.62 2 2 1 2 82084 1.88 0.62 6.3 0.82 3.27 3.82 10.27 0.59 18 LCPE 0.012 210 0.50 376.60 375.55 381.57 8.07 4.57 0 2 RUN 101-1 23115 0.53 0.61 1 1 NLET' 1 21201 0.49 0.60 1 1 NLET' 1 44316 1.02 0.61 6.3 0.82 3.27 2.03 12.29 0.20 24 LCPE 0.012 167 3.62 375.05 369 388.56 46.77 14.89 90 4 257319 5.91 0.64 c�>2015 D. R. STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 35 Technical Information Report City of Renton CB#17 TO INLET 2 17 17 16 17 2478 0.06 0.90 6.3 0.82 3.27 0.17 0.17 0.00 12 LCPE 0.012 24 4.11 403.60 402.6 406.60 7.84 9.99 0 2 16 16 15 16 27191 0.62 0.60 6.3 0.82 3.27 1.23 1.40 7.34 12 LCPE 0.012 93 5.28 402.60 397.7 406.60 8.89 11.32 90 2 RUN 115-15 2756 0.06 0.90 15 15 13 15 18860 0.43 0.62 ' 15 15 13 15 21616 0.50 0.66 6.3 0.82 3.27 1 07 2 47 0]6 12 LCPE 0.012 196 6.00 397.70 385.95 401.19 9.48 12.07 0 2 I RUN 113-13 4430 0.10 0.90 13 13 12 13 31481 0.72 0.60 13 13 12 13 35911 0.82 0.64 6.3 0.82 3.27 1.72 4.18 0.70 12 LCPE 0.012 100 8.72 385.95 377.27 389.44 11.43 14.55 0 2 12 12 11 12 2521 0.06 0.90 6.3 0.82 3.27 0.17 4.35 0.04 12 LCPE 0.012 31 1.01 377.27 376.96 383.59 3.89 4.95 107 4 11 11 NLET: 11 13691 0.31 0.56 6.3 0.82 3.27 0.58 4.93 0.13 12 LCPE 0.012 186 3.74 376.96 370 383.71 7.49 9.53 0 4 103408 2.37 0.63 CB#30 TO CB#4 30 30 29 30 4918 0.11 0.51 6.3 0.82 3.27 0.19 0.19 0.00 8 LCPE 0.012 76 5.30 396.33 392.33 398.00 3.02 8.66 0 2 29 29 28 29 4546 0.10 0.54 6.3 0.82 3.27 0.18 0.37 0.96 8 LCPE 0.012 70 5.71 392.33 388.33 394.00 3.14 8.99 90 2 28 28 27 28 4238 0.10 0.56 6.3 0.82 3.27 0.18 0.55 0.48 8 LCPE 0.012 70 5.71 388.33 384.33 390.00 3.14 8.99 13.5 2 27 27 26 27 4210 0.10 0.56 6.3 0.82 3.27 0.18 0.73 0.32 8 LCPE 0.012 70 2.00 384.33 382.93 386.00 1.86 5.32 76 2 26 26 25 26 4151 0.10 0.56 6.3 0.82 3.27 0.18 0.90 0.24 8 LCPE 0.012 69 2.00 382.93 381.55 385.25 1.86 5.32 28 2 25 25 24 25 4852 0.11 0.52 6.3 0.82 3.27 0.19 1.09 0.21 8 LCPE 0.012 142 1.99 381.55 378.73 385.00 1.85 5.30 13.5 2 24 24 4 24 0 0.00 0.90 6.3 0.82 3.27 0.00 1.09 0.00 8 LCPE 0.012 25 2.00 378.73 378.23 384.20 1.86 5.32 76 4 26915 0.62 0.54 CB#101 TO CB#1 101 101 1 101 23115 0.53 0.61 6.3 0.82 3.27 1.06 1.06 0.00 12 LGPE 0.012 24 2.00 385.55 385.08 388.55 5.47 6.96 90 2 CB#702 TO CB#2 102 102 2 102 40763 0.94 0.62 6.3 0.82 3.27 1.91 1.91 0.00 12 LCPE 0.012 24 6.04 378.57 377.1 381.57 9.51 12.11 90 2 CB#103 TO CB#3 103 103 3 103 2052 0.05 0.90 6.3 0.82 3.27 0.14 0.14 0.00 12 LCPE 0.012 51 1.78 378.89 377.98 381.89 5.17 6.58 46 2 CB#108 TO CB#8 108 108 8 108 9182 0.21 0.90 6.3 0.82 3.27 0.62 0.62 0.00 12 LCPE 0.012 24 2.92 391.14 390.43 394.14 6.61 8.42 90 2 CB#113 TO CB#13 113 113 13 113 4430 0.10 0.90 6.3 0.82 3.27 0.30 0.30 0.00 12 LCPE 0.012 24 2.01 386.44 385.95 389.44 5.49 6.99 90 2 CB#115 TO CB#15 115 115 15 115 2756 0.06 0.90 6.3 0.82 3.27 0.19 0.19 0.00 12 LCPE 0.012 24 2.01 398.19 397.7 401.19 5.49 6.99 90 2 c�>2015 D.R. STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 36 Technical Information Report City of Renton BACKWATER ANALYSIS MAP C2015 D. R. STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 37 Technical Information Report Ciry of Renton � W 2 II C9 y W � � � , . Z 2 � 3 N ti � 0 � � � � � � rc : L10 � p ? p4 37,933 SF o � � � � . V U w � � I�' � 2 m O I �- - ._ — . R108 R10 — — — � 9,182 SF R8 6,220 SF r ' 6,552 SF R9 5,398 S . R7 - - - — I 576 SF L8 - - - - L16 R6 12,426 SF L9 � 24,448 SF 2,238 SF 12,157 SF R17 � 2,478 SF R16 I � 2,743 SF L25 L26 4,852 SF 4,151 SF 4,2107SF 4,238 SF L29 L30 � T T T 4,54I SF 4,918 SF � � T T . 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P/PE N0. 8 P/PE NO. 9 JUNC NO. 9 � — � ,., . � JUN NO. 8 — _ __ _- \ ''. . � ' i JUNC NO. 7 , � JUNC NO. 6 �--- . � co Z I � � ' I I � � ' � . � � I I O � � � I i I J � � JUNC N0. .5 , � � Z I � � Q � J(l C N0. 4 � • m Q W O _r� � z � — — . _ � , F� Y � — � ! 20 � • . Q � � oO __ _ JUNC NO. 2 _ __._ . P/PE N0. 5 � P�PE N0. 3 P/PE NO. 2 JUNC NO. 1 I _ � � o Z _ _. — _� � PIPE N0. 4 ■ - - — � Z v U , � . -� � , � _ � JUNG, N0. 3 j � W \ r I I � I� � Z I � � ' i � � � I • II � � I �_ '' f� � � 1 �'�, � —`` l / '. , �1 1 �''. � N O RT H � �� GRAPHIC SCALE I � I 0 40 80 120 , / '— — `� �� ' wr�m er. xP � a�'gcnrFo er rtP � INCH — 8O FT. PR0.ECTENG7N£ER: NAJ I ' I DA7E.• 01.14J5 I PRGIECT NQ: 13717 / • I . . . I�I II ; R:�,20i3�11'�13717'�3'`Jroa:��gs'�?lots\figures�8ockwoter P:ode—L;nk',,Cg]OTOl1JLt;1.dn�, 5/20/2�?5 5:30:%0 A54 FDT p�7ANNy� BK/ I ��. CGPYF.�,CFiT Q 2�'4, D-4. S1P.�"JG CG'.�U_IF,� =NGINEE4S I��. 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SHEET.• B I � W � I 2 2 � � � � � � $ N ' � I 2 2 � 3 N o � � y y � � � � 2 � � � U 2 a � � � e � � i___-_� � � 2 � O . I O Wro ' i - — — — � . 1 _ _ __ � _ _ — � ___�_ _.�._.�._—_ � _ — — —�� 'I — — _ _ _ _ _ _ — �-�__�_..... � °�, �� . , � �� ; � i '�; �'; � � I ' i ; I � � E . I ' � ' I O ,� I � o � P/PE N0. 1 J � W � � � � � � � � o I 00 Q � Q - � o —� — I -�� _ _—_� I ~ Y ° � ,. — — . „ — z __ __-. . __ _ Q o -_ ____ - � � '_'_. . —. '�v �' � ..__ ... __. ._.__.. . _-__.. .__. I � ..._ ..___..___ ' ___ — — _ _ , �ts m 2 ,: W _ __- _ ___- r-� p C� � _ __ Q ' �- - - ' - - , O U . . � . � � _� V � 2 I� , � v 1 � ' � ! I' I = � � I � � .` I ' � � � I ; � , �- 1 '`:;_ � 1 , ,l 1 �'__ � N O RT H i �.� �� GRAPHIC SCALE 0 40 80 120 � � , oa,�m er.� rw i D£SICN£D BY• YLP 1 I N C H = 80 FT. ; PR(kECT ENpN£ER.•� MAJ ' � oa�• or.r+.rs I PRLLECT NO.: 13117 i • . . P,:�20J3�1�131i71310,-avr,�gs�Piots�fig;.�res�Backwater Node—Link,CBilSTOCv15.dwg 5/20/2015 9:49:26 A,4! 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SHE£T.• 9 �� 1 BACKWATER ANALYSIS RESULTS Pipe dG�a frcm fi�ie:CB=10 TO IP�LET "-.bwp Surcharge condition at intermediate junctions Tailwater Elevation:376.98 feet Discharge Range:1.92 to 12.29 Step of 1.037 [cfs] Overflow Elevation:399.55 feet Weir:NONE Upstream Velocity:0. feet/sec PIP� NO. 1: 167 LF - 24"CP @ 3.62� OUTLET: 369.00 INLET: 375.05 INTYP: 5 �UP]� NO. l: OVERFLOW-EL: 388.56 BEND: 90 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.20 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI �+********�********�*****�****�******************��******��***********��******* -.92 1.46 376.51 * 0.012 0.49 0.28 7.48 7.48 1.44 1.96 0.62 2 .96 1.50 376.55 * 0.�12 0.61 0.35 7.48 7.48 1.45 1.50 0.80 3.99 1.56 376.61 * 0.012 0.71 0.40 7.48 7.48 1.47 1.56 0.96 5.03 1.63 376.68 * 0.012 0.80 0.45 7.48 7.48 1.49 1.63 1.12 6. �7 1.71 376.76 * 0.012 0.88 0.49 7.48 7.48 1.52 1.71 1.26 %. 10 1.81 376.86 * 0.012 0. 95 0.53 7.48 7.48 1.55 1.81 1.41 8.14 1.91 376.96 * 0.012 1.02 0.57 7.48 7.48 1.59 1.91 1.56 3.18 2 .03 377.08 * 0.012 1.09 0.61 7.48 7.48 1.63 2.03 1.70 �_0.22 2.16 377.21 * 0.012 1.15 0.64 7.48 7.48 1.68 2.16 1.85 �i.25 2.30 377.35 * 0.012 1.21 0.67 7.48 7.98 1.74 2.30 2.01 12.29 2.44 377.49 * 0.012 1.27 0.71 7.48 7.98 1.80 2.44 2.16 13.33 2.61 377.66 * 0.012 1.32 0.74 7.48 7.48 1.88 2.61 2.32 FlPE NO. 2: 210 LF - 18"CF @ 0.50o OUTLET: 375.55 INLET: 376.60 INTYP: 5 JUNC NO. 2: OVERFLOW-EL: 381.57 BEND: 0 DEG DIA/WIDTH: 2.0 Q-RATIO: 0.59 Q;CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE H690 Hti^T� �,+ � �+**�*********************�******************�*********�**************+**�� -.60 0.65 377.25 * 0.012 0.48 0.46 0.96 0.96 0.48 ***** 0.65 � .47 0.83 377.43 * 0.012 0.60 0.58 1.00 1.00 0.60 ***** 0.83 3.34 0.98 377.58 * 0.012 0.70 0.68 1.06 1.06 0.70 ***** 0.98 4.20 1.13 377.73 * 0.012 0.79 0.77 1.13 1.13 0.79 ***** 1.13 5.07 1.37 377.97 * 0.012 0.87 0.87 1.21 1.21 0.87 1.37 1.27 5.93 1.49 378.09 * 0.012 0.95 0.96 1.31 1.31 0.96 1.49 i.41 ��.80 1.61 378.21 * 0.012 1.01 1.06 1.41 i.41 1.06 1.61 1.55 ^ .67 1.77 378.37 * 0.012 1.08 1.18 1.53 1.53 1.35 1.77 1.68 � .�3 2.25 378.85 * 0.012 1.14 1.34 1.66 1.66 1.79 2.25 1.83 9.40 2.74 379.34 * 0.012 1.19 1.50 1.80 1.80 2.18 2.74 2.02 10.26 3.27 379.87 * 0.012 1.24 1.50 1.94 1.94 2.60 3.27 2.22 11.13 3.85 380.45 * 0.012 1.28 1.50 2.11 2.11 3.07 3.85 2.43 PIPE N0. 3: 81 LF - 18"CP @ 1.07% OUTLET: 376.60 INLET: 377.48 INTYP: 5 JUNC N0. 3: OVERFLOW-EL: 382.48 BE�ID: 90 DEG DIA/WIDTH: 2.0 Q-RATIO: 0.03 Q(CFS) HW(FT) HW ELE�1. * N-FAC DC DN TW DO DE HWO HWI ****�***�*************�***********************************�**�**********�*�**** 1.01 0.50 377.98 * 0.012 0.38 0.30 0.65 0.65 0.38 ***** 0.50 1.55 0.64 378.12 * 0.012 0.47 0.37 0.83 0.83 0.47 ***** 0.64 2.09 0.76 378.24 * 0.012 0.55 0.43 0.98 0.98 0.55 ***** 0.76 2.64 0.87 378.35 * 0.012 0.62 0.49 1.13 1.13 0.62 ***** 0.87 3.18 0.98 378.96 * 0.012 0.68 0.54 1 .37 1.37 0.68 ***** 0.98 3.72 1.08 378.56 * 0.012 0.74 0.58 1.49 1.49 0.74 ***** 1.08 4.27 1.19 378.67 * 0.012 0.80 0.63 1.61 1.61 0.80 ***** 1.19 4.81 1.38 378.86 * 0.012 0.85 0.67 1.77 1.77 0.96 1.38 1.29 02015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 38 Technical Information Report City of Renton 5.35 1.81 379.29 * 0.012 0. 90 0.71 2.25 2.25 1.55 1.81 1.39 5.90 2.39 379.87 * 0.012 0. 94 0.76 2.74 2.74 2.08 2.39 1.50 6.44 3.03 380.51 * 0.012 0.99 0.80 3.27 3.27 2. 65 3.03 1.60 6.98 3.72 381.20 * 0.012 1.03 0.84 3.85 3.85 3.28 3.72 1.71 PIPE NO. 4: 27 LF - i8"CP @ 0.77% OUTLET: 377.48 INLET: 377.69 INTYP: 5 JUNC N0. 4: OVERFLOJJ-EL: 382.66 BEND: 48 DEG DIA/WIDTH: 2.0 Q-RATIO: 0.24 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI *�********************��*********x*********�*********�************************* 0.98 0.49 378.18 * 0.012 0.37 0.32 0.50 0.50 0.37 ***** 0.�9 1.51 0.61 378.30 * O.G12 0.47 0.90 0.64 0.64 0.47 ***** 0.61 2.04 0.72 378.41 * 0.012 0.54 0.97 0.76 0.76 0.54 ***** 0.72 2.57 0.81 378.50 * 0.012 0.61 0.52 0.87 0.87 0.61 ***** 0.81 3.09 0.98 378.67 * 0.012 0.67 0.58 0.98 0.98 0.73 0.98 0.89 3.62 1.05 378.79 * 0.012 0.73 0.63 1.08 1.08 0.85 1.05 0.96 4.15 1.14 378.83 * 0.012 0.79 0.68 1.19 1.19 0.97 1.14 1.03 4.68 1.27 378.96 * O.Oi2 0.84 0.73 1.38 1.38 1.18 1.27 1.09 5.21 1.69 379.38 * 0.012 0.88 0.78 1.81 1.81 1.66 1.69 1.15 5.74 2.29 379.98 * 0.012 0.93 0.82 2.39 2.39 2.25 2.29 1.21 6.27 2.95 380.64 * 0.012 0.97 0.87 3.03 3.03 2.90 2.95 1.26 6.80 3.67 381.36 * 0.012 1.01 0.91 3.72 3.72 3.61 3.67 1.31 PIPE N0. 5: 38 LF - 12"CP @ 8.24o OUTL_T: 378.19 I�LET: 381.36 I�TYP: 5 JUNC �O. 5: OVERFLG[^1-EL: 384.40 BEND: 47 DEG DIA/GIIDTH: 2 .0 Q-RATIO: G.10 Q;CFS) HW(Fi) H[�7 ELEV. * N-FAC DC DN TW DO D� HWO HWT �*��**********x+xx*x+*****x*�**��*********�*****�*�>*�__*�*��x********��***�x �.�9 0.47 381.83 * 0.012 0.38 0.19 0.00 0.19 0.38 ***** 0.47 1.21 0.61 381.97 * 0.012 0.47 0.23 0.11 0.23 0.47 ***** 0.61 1.64 0.74 382.10 * 0.012 0.55 0.26 0.22 0.26 0.55 ***** 0.74 2.06 0.85 382.21 * 0.012 0.62 0.30 0.31 0.31 0.62 ***** 0.85 2.49 0.97 382.33 * 0.012 0.68 0.33 0.48 0.48 0.68 ***** 0.97 2.91 1.09 382.45 * 0.012 0.74 0.35 0.55 0.55 0.74 ***** 1.09 3.34 1.23 382.59 * 0.012 0.79 0.38 0.64 0.64 0.79 ***** 1.23 3.76 1.39 382.75 * 0.012 0.83 0.91 0.77 0.77 0.83 ***** 1.39 4.19 1.58 382.94 * 0.a12 0.87 0.43 1.19 1.19 0.87 ***** 1.58 4.61 1.78 383.14 * 0.012 0.90 0.45 1.79 1.79 0.90 ***** 1.78 5.04 2.00 383.36 * 0.012 0.92 0.48 2.45 2.45 0.92 ***** 2.00 5.46 2.24 383.60 * 0.012 0.94 0.50 3.17 3.17 0. 94 ***** 2.24 PIPE N0. 6: 187 LF - 12"CP @ 4.03° OUTLET: 381.36 INLET: 388.90 INTYP: 5 JUNC N0. 6: OVERFLOw'-EL: 392.90 BEND: 46 DEG DIA/WIDTH: 2.0 Q-RATIO: 0.03 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI **********�**************��****************�*************************�*******�� 0.72 0.46 389.36 * 0.012 0.36 0.21 0.47 0.47 0.36 ***** 0.46 1.10 0.59 389.49 * 0.012 0.45 0.26 0.61 0.61 0.45 ***** 0.59 ! 1.49 0.71 389.61 * 0.012 0.52 0.30 0.74 0.74 0.52 ***** 0.71 1.88 0.81 389.71 * 0.012 0.59 0.34 0.85 0.85 0.59 ***** 0.81 2.26 0.92 389.82 * 0.012 0.65 0.38 0.97 0. 97 0.65 ***** 0.92 2.65 1.01 389.91 * 0.012 0.70 0.41 1.09 1.09 0.70 ***** 1.01 3.04 1.12 390.02 * 0.012 0.75 0.44 1.23 1.23 0.75 ***** 1.12 3.42 1.25 390.15 * 0.012 0.80 0.47 1.39 1.39 0.80 ***** 1.25 3.81 1.39 390.29 * 0.012 0.84 0.50 1.58 1.58 0.84 ***** 1.39 4.20 1.55 390.45 * 0.012 0.87 0.53 1.78 1.78 0.87 ***** 1.55 4.58 1.72 390.62 * 0.012 0.90 0.56 2.00 2.00 0.90 ***** 1.7? 4.97 1. 91 390.81 * 0.012 0.92 0.59 2.24 2.24 0.92 ***** 1.91 02015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 39 Technical Information Report City of Renton PIPE NO. 7: 5i LF - 12"CP @ 1.84% OUTLET: 388.90 INLET: 389.84 INTYP: 5 JUNC NO. 7: OVERFLOP7-EL: 394.84 BEND: 46 DEG DIA/WIDTH: 2.0 Q-RATIO: 0.01 Q(CFS) HW(FT} HVJ ELEV. * N-FAC DC DN TW DO DE HWO HWI ******************��*�****�**�******+****************�**************�***�****** 0.69 0.47 390.31 * 0.012 0.35 0.25 0.46 0.46 0.35 ***** 0.47 1.07 0.59 390.�3 * 0.012 0.44 0.31 0.59 0.59 0.44 ***** 0.59 1.44 0.70 390.54 * 0.012 0.51 0.36 0.71 0.�1 0.51 ***** 0.70 1.81 0.80 390.64 * 0.012 0.58 0.41 0.81 0.81 0.58 ***** 0.80 2.19 0.90 390.�4 * 0.012 0.64 0.46 0.92 0.92 0.64 ***** 0. 90 2.56 0.99 390.83 * 0.012 0.69 0.50 1.01 1.01 0.69 ***** 0.99 2.94 1.09 390.93 * 0.012 0.74 0.54 1.12 1.12 0.74 ***** 1. 09 3.31 1.21 391.05 * 0.012 0.78 0.58 1.25 1.25 0.78 ***** 1.21 3.68 1.34 391.18 * 0.012 0.82 0.62 1.39 1.39 0.82 ***** 1.34 4.06 1.56 391.40 * 0.012 0.86 0.67 1.55 1.55 1.18 1.56 1.48 4.43 1.91 391.75 * 0.012 0.89 0.71 1.72 1.72 1.46 1.9i 1.64 4.81 2.30 392.14 * 0.012 0.91 0.76 1.91 1.91 1.76 2.30 1.81 PIPE NO. 8: 78 LF - 12"CP @ 0.75a OUTLET: 389.84 INLET: 390.43 INTYP: 5 JUNC NO. 8: OVERFLOti+I-EL: 394.14 BEND: 0 DEG DIA/WIDTH: 2.0 Q-RATIO: 0.57 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ******�***�****�********x**********x*************�*******+***�**�******�******* 0.69 0.47 390.90 * 0.012 0.35 0.31 0.47 0.47 0.35 ***** 0.47 1.06 0.60 391.03 * 0.012 0.44 0.39 0.59 0.59 0.44 ***** 0. 60 1.43 0.72 391.15 * 0.012 0.51 0.46 0.70 0.70 0.51 ***** 0.72 1.80 0.83 391.26 * 0.012 0.58 0.53 0.80 0.80 0.58 ***** 0.83 2.17 0.94 391.37 * 0.0_2 0.63 0.59 0.90 0.90 0.63 ***** 0.94 2.54 1.05 391.48 * 0.012 0.69 0.66 0.99 0.99 0.69 ***** 1.05 2.91 1.20 391.63 * 0.012 0.74 0.73 1.09 1.09 0.90 1.20 1.16 3.28 1.53 391.96 * 0.012 0.78 0.81 1.21 1.21 1.19 1.53 1.29 3.65 1.87 392.30 * 0.012 0.82 1.00 1.34 1.34 1.45 1.87 1.44 4.02 2.34 392.77 * 0.012 0.85 1.00 1.56 1.56 1.82 2.34 1.61 4.39 2.95 393.38 * 0.012 0.88 1.00 1.91 1.91 2.34 2.95 1.79 4.76 3.62 394.05 * 0.012 0.91 1.00 2.30 2.30 2.91 3.62 1.99 I PIPE N�. 9: 183 LF - =2"CP @ 2.60° OUTLET: 390.93 INLET: 395.21 INTYP: 5 JUNC N0. 9: OVERFL05d-EL: 399.55 BEND: 90 DEG DIA/WIDTH: 2.0 Q-RATIO: 0.46 Q(CFS) HW{FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI � **********+***********x**************x**************�****************+****�*�** 0.44 0.36 395.57 * 0.012 0.28 0.18 0.47 0.47 0.28 ***** 0.36 0.67 0.47 395.68 * 0.012 0.35 0.23 0.60 0.60 0.35 ***** 0.47 0.91 0.56 395.77 * 0.012 0.41 0.26 0.72 0.72 0.41 ***** 0.56 1.15 0.64 395.85 * 0.012 0.46 0.30 0.83 0.83 0.46 ***** 0.64 1.38 0.72 395.93 * 0.012 0.50 0.33 0.94 0.94 0.50 ***** 0.72 1.62 0.81 396.02 * 0.012 0.55 0.35 1.05 1.05 0.55 ***** 0.81 1.86 0.89 396.10 * 0.012 0.59 0.38 1.20 1.20 0.59 ***** 0.89 2.09 0.97 396.18 * 0.012 0.62 0.40 1.53 1.53 0.62 ***** 0.97 2.33 1.05 396.26 * 0.012 0.66 0.43 1.87 1.87 0.66 ***** 1.05 2.57 1.14 396.35 * 0.012 0.69 0.45 2.34 2.34 0.69 ***** 1.14 2.80 1.22 396.43 * 0.012 0.72 0.48 2.95 2.95 0.72 ***** 1.22 3.04 1.32 396.53 * 0.012 0.75 0.50 3.62 3.62 0.75 ***** 1.32 C2015 D. R. STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 40 Technical Information Report City of Renton PIPE N0.10: 24 LF - 1L"CP @ 5.51`o OJTLET: 395.21 �NLET: 396.5� INTYP: 5 Q(CFS) HPT(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO Hti^�I **�********��**�******+*�*�**�*�******************��***********************+:t 0.30 0.28 396.83 * 0.012 0.23 0.13 0.36 0.36 0.23 ***** 0.�8 0.46 0.36 396.91 * 0.012 0.29 0.16 0.47 0.47 0.29 ***** 0.3r 0.62 0.43 396.98 * 0.012 0.33 0.18 0.56 0.56 0.33 ***** 0.43 0.78 0.49 397.04 * 0.012 0.38 0.20 0. 64 0.64 0.38 ***** 0.4u 0.95 0.55 397.10 * 0.012 0.41 0.22 0.72 0.72 0.41 ***** 0.55 1.11 0. 60 397.15 * 0.012 0.45 0.24 0.81 0.81 0.45 x**** 0. 5C 1.27 0.66 397.21 * 0.012 0.48 0.26 0.89 0.89 0.48 ***** 0. 5F 1.43 0.71 397.26 * 0.012 0.51 0.27 0.97 0.97 0.51 ***** 0.?1 1.59 0.76 397.31 * 0.012 0.54 0.29 1.05 1.05 0.54 ***** 0.?6 1.75 0.81 397.36 * 0.012 0.57 0.30 1.14 1.14 0.57 ***** 0. 81 1.92 0.8? 39?.42 * 0.012 O.bO 0.32 1.22 1.22 0.60 **X** 0. �',? L .�..�� V.G L J G� .�l X C.�_G �..�. l,^ ��.?_S �.J L �.l:. �.�L "f x x:F �� O� F-p�e data from rile:CB�_� �0 -t;LEI' 2.�;��rp Surcharge condition at ir.terried-ate junct--ons I Tailwater Elevation:376.48 feet Discharge Range:0.476 to 4. 93 Step of 0.475 [cts] Overflow Elevation:406.6 feet 9Jeir:NONE ' Upstream Velcc'_ty:0. feet/sec PIPE N0. 1: 186 LF - 12"CP @ 3.74� �UI'LET: �7C.00 L^J�E": 37E.96 IN�`iF: 5 JUNC N0. l: OVERFLO�C-EL: 383.71 BEND: 0 DEG DIA/WIDTH: 4.0 Q-RATIO: 0. 13 Q(CFS) HW{FT) HW ELEV. * N-�AC DC DN TW DO DE HG10 HjtiI **********�**********��***�+*x�********��*******�**********��*****��***�**xf �+ 0.48 0.37 377.33 * 0.012 0.29 0.18 6.48 6.48 0.29 ***** O.j? 0.95 0.54 377.50 * 0.012 0.41 0.25 6.48 6.48 0.41 ***** 0.54 1.43 0.68 377.64 * 0.012 0.51 0.30 6.48 6.48 0.51 ***** 0. 68 1.90 0.81 377.77 * 0.012 0.59 0.35 6.48 6.48 0.59 ***** 0. 81 2.38 0.93 377.89 * 0.012 0.67 0.39 6.48 6.48 0.67 ***** 0. ��3 2.86 1.04 378.00 * 0.012 0.73 0.43 6.48 6.48 0.73 ***** 1. n� 3.33 1.18 378.14 * 0.012 0.79 0.47 6.48 6.48 0.83 1.17 1. 18 3.81 1.64 378.00 * 0.012 0.84 0.51 6.48 6.48 1.34 1.64 1.3= 4.28 2.19 379.15 * 0.012 0.88 0.55 6.48 6.48 1.81 2.19 1. 52 �.76 2.82 379.78 * 0.012 0.91 0.59 6.48 6.48 2.35 2.82 1. �2 5.2� 3.51 380.47 * 0.012 0.°3 0.62 6.48 6.48 2.94 3.51 1. �� PIPE NO. 2: 30 LF - 12"CP @ 1. Olo OU'TLET: 376.96 INLET: 377.27 INTYP: � JUNC N0. 2: OVERFLOG7-EL: 383.59 BEND: 90 DEG DIA/WIDTH: 4 .0 Q-RATIO: O.C� Q(CFS) HG7(FT) HW ELEV. * N-FAC DC DN TW DO DE HF]0 HV�I **�***�**********x�+****�x��**��****�***��**+***��***x*******�***�***********+ 0.42 0.36 377.63 * 0.012 0.27 0.23 0.37 0.37 0.27 ***** 0.30 0.84 0.54 377.81 * 0.012 0.39 0.32 0.59 0.54 0.39 ***** 0.54 1.26 0.69 377.96 * 0.012 0.48 0.40 0.68 0.68 0.48 ***** 0. 6� 1.68 0.84 378.11 * 0.012 0.56 0.47 0.81 0.81 0.56 ***** 0.8^ 2.10 0.98 378.25 * 0.012 0.62 0.53 0.93 0.93 0. 62 ***** G. �� 2.52 1.18 378.45 * 0.012 0.69 0.59 1.04 1.04 0.81 1.18 1.-3 2.94 1.45 378.72 * 0.012 0.74 0.66 1.18 1.18 1.05 1.45 1.?9 3_36 2_08 379_35 * 0.012 0.79 0_72 1.64 1.64 1.56 2.08 L�� 3.78 2.83 380.10 * 0.012 0.83 0.80 2.19 2.19 2.17 2.83 1.;1 4.20 3.68 380.95 * 0.012 0.87 1.00 2.82 2.82 2.87 3.68 1. ��, 4.62 4.62 381.89 * 0.012 0.90 1.00 3.51 3.51 3. 64 �.62 2.�2 G2015 D. R. STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 41 Technical Information Report City of Renton PIPE N0. 1: 99 LF - `_2"CP @ 8.72'� CUTLE'I': 377.2i II�LET: 3�5. 95 INTYP: 5 JUNC N0. 3: OVERFLOW-EL: 389.44 BEND: 0 DEG DIA/WIDTH: 2.0 Q-RATIO: 0.^J Q(CFS) HW(FTJ HW ELEV. x N-FAC D� DN TW DO DE HTtiO H��?- ******�*x�*��*�******��*�*��**+**********��*�******************�*******�> 0.40 0.31 386.26 * 0.012 0.27 0.13 0.36 0.36 0.27 ***** 0.31 0.81 0.48 386.43 * 0.012 0.38 0.19 0.54 0.54 0.38 ***** 0.=� 1.21 0.62 386.57 * 0.012 0.47 0.23 0.69 0.69 0.47 ***** 0. 62 1.62 0.74 386.69 * 0.012 0.54 0.26 0.84 0.84 0.54 ***** 0.?4 2.02 0.86 386.81 * 0.012 0.61 0.29 0.98 0.98 0.61 ***** 0.8'0 2.42 0.98 386.°3 * 0.012 0.67 0.32 1.18 1.18 0.67 ***** 0. 9� 2.83 1.10 387.05 * 0.012 0.73 0.34 1.45 L 45 0.73 ***** 1.=0 3.23 1.25 387.20 * 0.012 0.77 0.37 2 .08 2.08 0.77 ***** 1.2� 3.64 1.42 387.37 * a.012 0.82 0.39 2 .83 2.83 0.82 ***** 1.�� 4.04 1.60 387.55 * O.Oi2 0.86 0.42 3.68 3.68 0.86 ***** 1. 6C, 4.44 1.81 387.76 * 0.0�2 0.89 0.44 4 .62 4.62 0.89 ***** 1.8_ PIPE NO. 4: 195 LF - 12"CP @ 6.00° OUTLET: 385.95 INLET: 397.70 INTYP: � JUNC NO. 4: OVERFLOTr7-EL: 401.19 BEND: 0 DEG DIA/ti17IDTH: 2 .0 Q-RATIO: 0.?0 Q(CFS� HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO H��I �***�***************+***********��**********��**************�*�**********��+ 0.24 0.24 397.94 * 0.012 0.21 0.11 0.31 C.31 0.21 ***** 0.2� 0.48 0.36 398.06 * 0.012 0.29 0.16 0.48 0.48 0.29 ***** 0. 36 0.71 0.46 398.16 * 0.012 0.36 0.19 0.62 0.62 0.36 ***** 0. 46 0.95 0.54 398.24 * 0.012 0.41 0.22 0.74 0.74 0.41 ***** 0.5'_ 1.19 0.62 398.32 * 0.012 0.47 0.29 0.86 0.86 0.47 ***** 0. 62 1.43 0.70 398.40 * 0.012 0.51 0.27 0.98 0.98 0.51 ***** 0.70 1. 67 0.77 398.47 * 0.012 0.55 0.29 1.10 1.10 0.55 ***** 0.77 1.90 0.84 398.54 * 0.012 0.59 C.31 1.25 1.25 0.59 ***** 0. 8G 2.14 0.92 398.62 * 0.012 0.63 0.33 1.42 1.42 0.63 ***** O. G2 2.38 0.99 398.69 * 0.012 0.67 0.35 1.60 1.60 0.67 ***** O. G9 2.62 1.06 398.76 * 0.012 0.70 0.36 1.81 1.81 0.70 ***** 1. 06 PIPE NO. 5: 92 LF - 12"CP @ 5.28° OUTLET: 397.70 INLET: 402.60 INTYP: 5 JUNC N0. 5: OVERFL067-EL: 406.60 BEND: 90 DEG DIA/6ti7IDTH: 2.0 Q-RATIO: 7.34 Q(CFS) HW(FT} HW ELEV. * N-FAC DC DN TVu' DO DE HWO HY�I �c:Fi:i::kic�:ic*i:**:F:F*:F:F:F:F�1'it�;i:�.-�'F�'hi;�:***************:F*#*:F:F******�'F:F�'F k*�'F*i:-k�:�:*iF*****:F>t�c i�l:;F 0.14 0.18 402.78 * 0.012 0.16 0.09 0.24 0.24 0.16 ***** 0. 18 0.27 0.26 902.86 * 0.012 0.22 0.12 0.36 0.36 0.22 ***** 0.26 0.41 0.33 402.93 * O.Oi2 0.27 0.15 0.46 0.46 0.27 ***** 0.3? 0.54 0.39 402.99 * 0.012 0.31 0.17 0.54 0.54 0.31 ***** 0.�9 0.68 0.45 403.05 * 0.012 0.3� 0.19 0.62 0.62 0.35 ***** 0. 4� 0.81 0.50 403.10 * 0.012 0.38 0.21 0.70 0.70 0.38 ***** 0.5C 0.95 0.55 403.15 * 0.012 0.41 0.23 0.77 0.77 0.41 ***** 0.5� 1.08 0.60 403.20 * 0.012 0.44 0.24 0.84 0.84 0.44 ***** 0. 6C 1.22 0.64 403.24 * 0.012 0.47 0.26 0.92 0.92 0.47 ***** 0. r� 1.35 0.69 403.29 * 0.012 0.50 0.27 0.99 0.99 0.50 ***** 0. 69 1.49 C.?3 40=,.3? * 0.012 G,52 G.2R " .C6 1 .06 C .:.2 ***** 0.73 ��2015 D. R. STRONG Consulting Engineers Inc. The Endave at Bridle Ridge Page 42 Technical Information Report City of Renton PIPE NO. 6: 24 LF - 12"CF @ 4.11% OUTLET: 402.60 INLET: 403.60 INTYP: 5 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI �*�*****x****�*+**+�*��****+��**�***********�*��**************************** 0.02 0.06 403.66 * 0.012 0.06 0.04 0.18 0.18 0.06 ***** 0.05 0.03 0.08 403.68 * 0.012 0.08 0.05 0.26 0.26 0.08 ***** 0.08 I 0.05 0.10 403.70 * 0.012 0.09 0.06 0.33 0.33 0.09 ***** 0.10 0.06 0.12 403.72 * 0.012 0.11 0.07 0.39 0.39 0.11 ***** 0.12 0.08 0.14 403.74 * 0.012 0.12 0.08 0.45 0.45 0.12 ***** 0.14 0.10 0.15 403.75 * 0.012 0.13 0.08 0.50 0.50 0.13 ***** 0.15 ' 0.11 0.16 403.76 * 0.012 0.14 0.09 0.55 0.55 Q.14 ***** 0.16 0.13 0.18 403.78 * 0.012 0.15 0.09 0.60 0.60 0.15 ***** 0.18 0.15 0.19 403.79 * 0.012 0.16 0.10 0.64 0.64 0.16 ***** 0.19 0.16 0.20 403.80 * 0.012 0.17 0.10 0.69 0.69 0.17 ***** 0.20 ' 0.18 0.21 403.81 * 0.012 0.18 0.11 0.73 0.73 0.18 ***** 0.21 Pipe data from file:CB#30 TO CB#4.bwp '' Surcharge conditicn at intermediate junctions Tailwater Elevation:380.64 feet Discharge Range:0.19 to 1.09 Step cf 0.09 [cfs] I Overflow Elevation:398. ieet ', tie'eir:NONE Upstream Velocity:0. feet/sec ' PIPE N0. 1: 25 LF - 8"CP @ 2.00% OUTLET: 378.23 INLET: 378.73 INTYP: 5 __ ' JUNC N0. 1: OVERFLOW-E�: 384.20 BEND: 76 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.00 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI �*********��*��**�****�*�**�**x�*+��***�*��****x***�*********�*******�********* C.19 1.93 380.66 * 0.012 0.21 0.15 2.41 2.41 1.92 1.93 0.27 C.28 1.94 380.67 * O.C12 0.25 0.18 2.41 2.41 1.92 1.94 0.33 0.37 1.96 380.69 * 0.012 0.29 0.21 2.4� 2.41 1.93 1.96 0.39 0.46 1.98 380.71 * O.C12 0.32 0.23 2.41 2.41 1.94 1.98 0.45 , - 0.55 2.01 380.74 * 0.012 0.35 0.25 2.41 2.41 1.95 2.01 0.50 0.64 2.05 380.�8 * 0.012 0.38 0.28 2.41 2.41 1.97 2.05 0.56 ' 0.73 2.09 380.82 * 0.012 0.41 0.30 2.41 2.41 1.99 2.09 0.61 ', � 0.82 2.13 380.86 * 0.012 0.43 0.32 2.41 2.41 2.01 2.13 0.66 �' 0.91 2.19 380.92 * 0.012 0.46 0.34 2.41 2.41 2.03 2.19 0.71 I ,- , 1.00 2.24 380.9� * 0.012 0. 48 0.35 2.41 2.41 2.06 2.24 0.76 ' 1.09 2.31 381.04 * 0.012 0.50 0.37 2.41 2.41 2.OS 2.31 0.82 PIPE N0. 2: 142 LF - 8"CP @ 1. 99% OUTLET: 378.73 INLET: 381.55 INTYP: 5 JUNC NO. 2: OVERFL04v-EL: 385.00 BEND: 13 DEG DIA/N7IDTH: 2.0 Q-RATIO: 0.21 Q(CFS) H�i�(FT� HTnJ ELEV. * N-FAC DC DN TW DO Dr� HWO Hbti'I ******x��*� ��+*******x***�**��**x*�� r**************��*��**��***��***�*******�_ 0.19 0.27 381.82 * 0.012 0.21 0.15 1.93 1.93 0.21 ***** G.�� 0.28 0.33 381.88 * 0.012 0.25 0.18 1.94 1. 94 0.25 ***** 0.3; 0.37 0.39 381.94 * C.012 0.29 0.21 1.96 1.96 0.29 ***** 0.?�+ 0.46 0.44 381.99 * C.012 0.32 0.23 1.98 L 98 0.32 ***** 0.=_4 0.55 0.48 382.03 * 0.012 0.35 0.25 2.01 2.01 0.35 ***** 0.=� ' 0.64 0.53 382.08 * 0.012 0.38 0.28 2.05 2.05 0.38 ***** 0.53 0.73 0.57 382.12 * 0.012 0.41 C.30 2.09 2.09 0.41 ***** 0.5- 0.82 0.62 382.17 * 0.012 0.43 0.32 2.13 2.13 0.43 ***** 0.6� 0. 91 0.66 382.21 * 0.012 0.46 0.34 2.19 2.19 0.46 ***** 0.66 1.00 0.70 382.25 * 0.012 0.48 0.35 2.24 2_24 0_48 ***** 0.70 1. 0° C.75 382.30 * 0.0_2 0.50 0.3? 2.31 2.31 0.50 ***** 0.75 s^2015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 43 Technical Information Report City of Renton PIPE N0. 3: 69 LF - 8"CP @ 2.00� OUTLET: 381.55 INLET: 382.93 INTYP: 5 JUNC N0. 3: OVERFLOW-EL: 385.25 BEND: 28 DEG DIA/WIDTH: 2.0 Q-RATIO: 0.24 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ***************+***+******�**�******************�******�*****�********�******** 0.16 0.24 383.17 * 0.012 0.19 0.19 0.27 0.27 0.19 ***** 0.24 0.23 0.30 383.23 * 0.012 0.23 0.16 0.33 0.33 0.23 ***** 0.30 0.31 0.35 383.28 * 0.012 0.26 0.19 0.39 0.39 0.26 ***** 0.35 0.38 0.39 383.32 * 0.012 0.29 0.21 0.44 0.44 0.29 ***** 0.39 0.45 0.44 383.37 * 0.012 0.32 0.23 0.48 0.48 0.32 ***** 0.44 0.53 0.48 383.41 * 0.012 0.35 0.25 0.53 0.53 0.35 ***** 0.48 0.60 0.52 383.45 * 0.012 0.37 0.27 0.57 0.57 0.37 ***** 0.52 0.68 0.56 383.49 * 0.012 0.39 0.28 0.62 0.62 0.39 ***** 0.56 0.75 0.59 383.52 * 0.012 0.42 0.30 0.66 0.66 0.92 ***** 0.59 0.83 0.63 383.56 * 0.012 0.44 0.32 0.70 0.70 0.44 ***** 0.63 0.90 0.67 383.60 * 0.012 0.96 0.33 0.75 0.75 0.96 ***** 0.67 PIPE N0. 4: 69 LF - 8"CP @ 2.00g OUTLET: 382.93 INLET: 384.33 INTYP: 5 JUNC N�. 4: OVERFLOV7-EL: 386.00 BEND: 76 DEG DIA/WIDTH: 2.0 Q-RATIO: 0.32 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI **�************************+*�*********************�*********�*******�***�***** 0.13 0.22 384.55 * 0.012 0.17 0.12 0.24 0.24 0.17 ***** 0.22 0.19 0.27 384.60 * 0.012 0.20 0.15 0.30 0.30 0.20 ***** 0.27 0.25 0.31 384.64 * 0.012 0.23 0.17 0.35 0.35 0.23 ***** 0.31 0.31 0.35 384.68 * 0.012 0.26 0.19 0.39 0.39 0.26 ***** 0.35 0.37 0.39 384.72 * 0.012 0.29 0.21 0.44 0.44 0.29 ***** 0.39 0.43 0.93 384.76 * 0.012 0.31 0.22 0.48 0.48 0.31 ***** 0.43 0.49 0.47 384.80 * 0.012 0.33 0.24 0.52 0.52 0.33 ***** 0.47 0.55 0.51 384.84 * 0.012 0.35 0.25 0.56 0.56 0.35 ***** 0.51 0.61 0.54 384.87 * 0.012 0.37 0.27 0.59 0.59 0.37 ***** 0.59 0.67 0.58 384.91 * 0.012 0.39 0.28 0.63 0.63 0.39 ***** 0.58 0.73 0.62 384.95 * 0.012 0.41 0.30 0.67 0.67 0.41 ***** 0.62 PIF� NO. 5: 70 LF - 8"CP @ 5.71� OUTLET: 384.33 INLET: 388.33 INTYP: 5 7r [d� N0. 5: OVERFLOW-EL: 390.00 BEND: 13 DEG DIA/WIDTH: 2.0 Q-RATIO: 0.48 ', Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI � k>*�****************�*�****�***************+****************�***************** 0.10 0.17 388.50 * 0.012 0.15 0.09 0.22 0.22 0.15 ***** 0.17 0.14 0.22 388.55 * 0.012 0.18 0.10 0.27 0.27 0.18 ***** 0.22 0.19 0.25 388.58 * 0.012 0.20 0.12 0.31 0.31 0.20 ***** 0.25 0.23 0.29 388.62 * 0.012 0.23 0.13 0.35 0.35 0.23 ***** 0.29 0.28 0.32 388.65 * 0.012 0.25 0.14 0.39 0.39 0.25 ***** 0.32 0.32 0.35 388.68 * 0.012 0.27 0.15 0.43 0.43 0.27 ***** 0.35 0.37 0.38 388.71 * 0.012 0.29 0.16 0.47 0.47 0.29 ***** 0.38 I 0.41 0.40 388.73 * 0.012 0.30 0.17 0.51 0.51 0.30 ***** 0.40 0.96 0.43 388.76 * 0.012 0.32 0.18 0.54 0.54 0.32 ***** 0.43 0.50 0.46 388.79 * 0.012 0.34 0.19 0.58 0.58 0.34 ***** 0.46 0.55 0.48 388.81 * 0.012 0.35 0.19 0.62 0.62 0.35 ***** 0.48 02015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 44 Technical Information Report City of Renton P�PE NO. 6: 6° LF - E'"CP @ 5.710 OJZLET: 3b8.33 Ii�LE7: 392.33 INTYF: 5 JUNC NO. 6: OVERFLOW-E�: 394.00 BEND: 90 DEG DIA/WIDTH: 2.0 Q-RATIO: 0. 96 Q(CFS) HW(FT) H�V ELEV. * N-FAC DC DN TW DO DE HWO HWI *x*********��*�***�******�*****�*�*�****�**��****+*�**********************�xx,.� 0.06 0.14 392.47 * 0.012 0.12 0.07 0.17 0.17 0.12 ***** 0. 14 0.10 0.17 392.50 * 0.012 0.15 0.08 0.22 0.22 0.15 ***** 0. 1? 0.13 0.20 392.53 * 0.012 0.17 0.10 0.25 0.25 0.17 ***** 0.�0 0.16 0.23 392.56 * 0.012 0.19 0.11 0.29 0.29 0.19 ***** 0.�3 0.19 0.26 392.59 * 0.012 0.20 0.12 0.32 0.32 0.20 ***** 0.2F 0.22 0.28 392.61 * 0.012 0.22 0.12 0.35 0.35 0.22 ***** 0.28 0.25 0.30 392.63 * 0.012 0.24 0.13 0.38 0.38 0.24 ***** O.iO 0.28 0.32 392.65 * 0.012 0.25 0.14 0.40 0.40 0.25 ***** 0.32 0.31 0.35 392.68 * 0.012 0.26 0.15 0.43 0.43 0.26 ***** 0.35 0.34 0.37 392.70 * 0.012 0.28 0.15 0.46 0.46 0.28 ***** 0.3? 0.37 0.39 392.72 * 0.012 0.29 O.lo 0.48 0.48 0.29 ***** O.j�' PIPE N0. 7: 75 LF - 8"CP @ 5.30° OUTLET: 392.33 INLET: 396.33 II�TYP: 5 Q(CFS) HW(FT� HW ELEV. * N-FAC DC DN TW DO DE HinIO HTr�I ****�*�x�****��*******�***��x**��**�***��**�********�*��*�***+*��**********+�t 0.03 0.09 396.42 * 0.012 0.09 0.05 0.14 0.14 0.09 ***** 0. 0�' 0.05 0.12 396.45 * 0.012 0.10 0.06 0.17 0.17 0.10 ***** 0. 12 0.06 0.14 396.47 * 0.012 0.12 0.07 0.20 0.20 0.12 ***** 0. 14 0.08 0.16 396.49 * 0.012 0.13 0.08 0.23 0.23 0. 13 ***** 0. 15 0.10 0.17 396.50 * 0.012 0.15 0.09 0.26 0.26 0. 15 ***** 0. 1? 0.11 0.19 396.52 * 0.012 0.16 0.09 0.28 0.28 0. 16 ***** 0. 19 0.13 0.20 396.53 * 0.012 0.17 0.10 0.30 0.30 0. 17 ***** 0.2C 0.14 0.22 396.55 * 0.012 0. 18 0.10 0.32 0.32 0.18 ***** 0.22 0.16 0.23 396.56 * 0.012 0. 19 0.11 0.35 0.35 0.19 ***** 0.23 C.l? G.25 306.�3 * �.012 0.20 J.11 0.3`' :1.3i Q_�0 ***** C.�5 C.1� ., .26 3'�6.� , * ��.C12 O.�l �.12 G._�� J.�9 0.�� ***** C.26 G2015 D. R. STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 45 Technical Information Report City of Renton Pipe data from file:CB#101 TO CB#l.bwp Surcharge condition at intermediate junctions Tailwater Elevation:377.49 feet Discharge Range:0.106 to 1.06 Step of 0.106 [cfs] Overflow Elevation:388.55 feet Weir:NONE Upstream Velocity:0. feet/sec PI?E N0. 1: 23 LF - "-2"CP @ 2.00° OUTLET: 385.08 INLET: 385.55 INTYP: 5 Q,CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ��_:_��***�***��*�***********+�********�********+*********+***************** �.11 0.17 385.72 * 0.012 0.14 0.10 0.00 0.10 0.14 ***** 0.17 �i.21 0.25 385.80 * 0.012 0.19 0.14 0.00 0.14 0.19 ***** 0.25 �i.32 0.31 385.86 * 0.012 0.24 0.17 0.00 0.17 0.24 ***** 0.31 �.42 0.36 385.91 * 0.012 0.27 0.19 0.00 0.19 0.27 ***** 0.36 0.53 0.41 385.96 * 0.012 0.31 0.22 0.00 0.22 0.31 ***** 0.41 C.64 0.45 386.00 * 0.012 0.34 0.24 0.00 0.24 0.34 ***** 0.45 �.74 0.49 386.04 * 0.012 0.36 0.25 0.00 0.25 0.36 ***** 0.49 C .85 0.53 386.08 * 0.012 0.39 0.27 0.00 0.27 0.39 ***** 0.53 C .95 0.57 386.12 * 0.012 0.41 0.29 0.00 0.29 0.41 ***** 0.57 _ .C6 0.61 386.16 * 0.012 0.44 0.30 0.00 0.30 0.44 ***** 0.61 =�ipe data from file:CB#102 TO CB€2.bwp S�archarge condition at internediate junctions �ailwater Elevation:379.87 feet Discharge Range:0.19i to l. y� Step or C. 191 [�=s] �verflow Elevation:381.57 feet Weir:NONE Jpstream Velocity:0. feet/sec r=-'E NO. 1: 24 LF - 12"CP @ 6.04`s OUTL�T: 377.10 I�LET: 378.57 INTYP: 5 ��(CFS) HW(FT) Ei4 ELEV. * N-FAC DC DN TW DO D� HWO H�^?= . r +****:t*:t*�*******��***�*i.*:t**i.*********,k+�*******i.*********�*************i t,. C .`-9 1.31 379.68 * 0.012 0.18 0.10 2.77 2.77 1.31 1.31 Q.21 C.38 1.31 379.88 * 0.012 0.26 0.14 2.77 2.77 1.30 1.31 0.�: J.57 1.32 379.89 * 0.012 0.32 0.17 2.77 2.77 1.31 1.32 0.40 J.�6 1.33 379.90 * 0.012 0.37 0.20 2.77 2.77 1.31 1.33 0.48 ��. 95 1.35 379.92 * 0.012 0.42 0.22 2.77 2.77 1.31 1.35 0.55 1. 15 1.37 379.94 * 0.012 0.46 0.24 2.77 2.77 1.32 1.37 0.61 1.34 1.40 379.97 * 0.012 0.49 0.26 2.77 2.77 1.33 1.40 0.68 1.53 1.43 380.00 * 0.012 0.53 0.28 2.77 2.77 1.34 1.43 0.7� 1.72 1.46 380.03 * 0.012 0.56 0.29 2.77 2.77 1.35 1.46 0.80 � .°1 -•5n 350. . � ��.012 0.5y 0.�1 2 . , . ?. . . _.36 1 .�0 C.�6 ��2015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 46 Technical Information Report City of Renton Pipe data frcm file:CB�iO3 i0 CB�3.ti�,�p Surcharge condition at intermediGte _______� Tailwater Elevation:380.51 feet Discharge Range:0.014 to 0.19 Step of O.G_= [cfs= Overflow Elevation:381.89 feet Weir:NONE Upstream Velocity:0. feet/sec PIPE N0. l: 51 LF - 12"CP @ 1.78. :;U-L=- : ? . . _ -IdL�T: � _ . �_ �II==F: ` Q(CFS) HW(FT} HW ELEV. * N-FAC DC DN TW DO DE HWO fi�^I= ***********�***++*****�*****�***�**************�*��***********+�***�********�tr 0.01 1.63 380.52 * 0.012 0.05 0.04 2.53 2.53 1.63 1.63 O.Gr, 0.03 1.62 38�.51 * 0.012 0.07 0.06 2.53 2.53 1.62 1.62 O.G� 0.04 1.62 380.51 * 0.012 0.09 0.07 2.53 2.53 1.62 1.62 0. -:� 0.06 1.62 380.51 * 0.012 0.10 0.08 2.53 2.53 1.62 1.62 0.=� 0.07 1.62 380.51 * 0.012 0.11 0.09 2 .53 2.53 1.62 1.62 0. -= 0.08 1.62 380.51 * 0.012 0.12 0.09 2 .53 2.53 1.62 1.62 0."� 0.10 1.62 380.51 * 0.012 0.13 0.10 2.53 2.53 1.62 1.62 O.-b 0.11 1.62 380.51 * 0.012 0.14 0.11 2.53 2.53 1.62 1.62 0. -; 0.13 1.62 380.51 * 0.012 0.15 0.11 2.53 2.53 ?.62 1.62 C. _� 0.14 1.62 380.51 * 0.012 C, -6 r ,-� 2 .53 _ .�3 - . c�2 1.6% r,�0 Pipe data from file:CB#108 TO CB#8.b�ap Surcharge condition at �-ntermediate jnnct_�ns Tailw�ter Elevation:393.38 -eet Discharge Range:0.062 to 0. .,� �tep .- C.C:�.. _ -s] Overflow Elevation:394.14 fe�t Weir:NONE Upstream Velocity:0. feet/sec PIPE N0. l: 24 LF - �2"CP @ 2.92% O[:TLET: 3°G.43 INLET: 3°1. 14 INTYF: `, Q(CFS) HW(FT) HV7 ELEV. * N-FAC DC DN TW DO DE HWO HV�I ***********x*****�**�x**��*�****************+************************�*****�tN� 0.06 2.25 393.39 * 0.012 0.11 0.07 2.95 2.95 2.25 2.25 0. 12 0.12 2.24 393.38 * 0.012 0.15 0.10 2.95 2.95 2.24 2.24 0. 1�� 0.19 2.24 393.38 * 0.012 0.18 0.12 2.95 2.95 2.24 2.24 0.22 0.25 2.24 393.38 * 0.012 0.21 0.14 2.95 2.95 2.24 2.24 0.2h 0.31 2.25 393.39 * 0.012 0.23 0.15 2.95 2.95 2.24 2.25 0.30 0.37 2.25 393.39 * 0.012 0.26 0.17 2.95 2.95 2.24 2.25 0.33 0.43 2.25 393.39 * 0.012 0.28 0.18 2.95 2.95 2.24 2.25 0.36 0.50 2.25 393.39 * 0.012 0.30 0.19 2.95 2.95 2.24 2.25 0.39 0.56 2.26 393.40 * 0.012 0.32 0.20 2.95 2.95 2.25 2.26 0.41 O. o2 2.25 39?.40 * C.��12 C.33 0.2- 2.95 2.�5 2.25 2.26 �. 44 ��2015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 47 Technical Information RepoR City of Renton Pipe data from file:CB#113 TC CB�l�.b.�c Surcharge condition at intermedia�e juncticns Tailwater Elevation:387.65 feet Discharge Range:0.03 to 0.3 Step cf 0.03 [c-�] Overflow Elevation:389.44 feet Weir:NONE Upstream Velocity:0. feet/sec PIPE NO. 1• 24 LF - 12"CP @ 2.01`; G=iT�ET• 3�5. 9� I`1JE^: 386. 44 I`:Ti=: � Q(CFS) HVd(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO H+'�I �*x******�**�*�****�**�**��***�*************�*************�**�**�***x�******��* 0.03 1.22 387.66 * 0.012 0.08 0.06 1.70 1.70 1.22 1.22 O.C9 0.06 1.21 387.65 * 0.0�2 0.10 0.08 1.70 1.70 1.21 1.21 0.12 0.09 1.21 387.65 * 0.012 0.13 0.09 1.70 1.70 1.21 1.21 0.16 0.12 1.21 387.65 * 0.012 0.15 0.11 1.70 1.70 1.21 1.21 0.18 0.15 1.21 387.65 * 0.012 0.16 0.12 1.70 1.70 1.21 1.21 0.20 0.18 1.21 387.65 * 0.012 0.18 0.13 1.70 1.70 1.21 1.21 0.22 0.21 1.21 387.65 * 0.012 0.19 0.14 1.70 1.70 1.21 1.21 0.2= 0.24 1.21 387.65 * 0.012 0.21 0.15 1.70 1.70 1.21 1.21 0.26 0.27 1.21 387.65 � 0.012 0.22 0.16 1.70 1.70 1.21 1.21 0.28 0.3Q 1.21 3R7.65 * 0.012 0.23 0.16 1.70 1.70 1.21 1.21 0.3C 0.33 1.22 387.66 * 0.012 0.24 0.17 1_?0 l.?0 1.21 L 22 0.�- Pipe data from file:CB#115 TO CB#15.bwp Surcharge condition at intermediate junctions Tailwater Elevation:398.76 feet Discharge Ra�qe:0.019 to C. _. Step ..� C.Cl� [�=s] Overflow EletTation:401.19 feet G7eir:NONE Upstream Veloc_ty:0. feet/sec PIPE N0. 1: 24 LF - 12"CP @ 2.C_° OLTLET: 397.7C I^_d�Er: 398. 19 I=d'IY"F: � Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HY�I ****��**�**��*�****x**�***�**��**+***+**�***�**************++***��**�x******��* 0.02 0.58 398.77 * 0.012 0.06 0.05 1.06 1.06 0.58 0.58 0.07 0.04 0.57 398.76 * 0.012 0.08 0.06 1.06 1.06 0.57 0.57 0.10 0.06 0.57 398.76 * 0.012 0.10 0.08 1.06 1.06 0.57 0.57 0. 12 0.08 0.57 398.76 * 0.012 0.12 0.09 1.06 1.06 0.57 0.57 0. 1� 0.09 0.57 398.76 * 0.012 0.13 0.10 1.06 1.06 0.57 0.57 0. 1� 0.11 0.57 398.76 * 0.012 0.14 0.10 1.06 1.06 0.57 0.57 0. 18 0.13 0.57 398.76 * 0.012 0.15 0.11 1.06 1.06 0.57 0.57 0. 19 0.15 0.57 398.76 * 0.012 0.16 0.12 1.06 1.06 0.57 0.57 0.20 0.17 0.57 398.76 * 0.012 0.17 0.13 1.06 1.06 0.57 0.57 0.22 0.19 0.57 3°8.?6 * O.C12 0.1E Q.13 �.06 _.C6 0.57 0.57 0.2? J.Ll 0.5 , _ �iE .�'6 �.�..1L .i.l', �.,'. 14 -.C� -.i�. � .51 0.5"' O.G4 �2015 D. R.STRONG Consulting Engineers Ina The Enclave at Bridle Ridge Page 48 Technical Information Report City of Renton SECTION VI SPECIAL REPORTS AND STUDIES The following report and studies have been provided with this submittal. 1. Traffic Impact Analysis—TraffEx, Inc., December 27, 2013 2. Critical Areas Study— Sewall Wetland Consulting, Inc., February 3, 2014 3. Geotechnical Engineering Study— Earth Solutions NW LLC, February 5, 2014 4. Arborist Report— GreenForest, Inc., February 18, 2014 �, . 02015 D.R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 49 Technical Information Report City of Renton SECTION VII OTHER PERMITS, VARIANCES AND ADJUSTMENTS 1. Boundary Line Adjustment— City of Renton 2. Construction Stormwater General Permit—WSDOE r ; i � i ;-� 02015 D.R.STRONG Consulting Engineers inc. The Enclave at Bridle Ridge Page 50 Technical Information Report City of Renton SECTION VI11 ESC PLAN ANALYSIS AND DESIGN (PART A) The Erosion and Sedimentation Control Design meets the nine minimum requirements: 1. Clearing Limits — Areas to remain undisturbed shall be delineated with a high- visibility plastic fence prior to any Site clearing or grading. 2. Cover Measures — Disturbed Site areas shall be covered with mulch and seeded, as appropriate, for temporary or permanent measures. 3. Perimeter protection — Perimeter protection shall consist of a silf fence down slope of any disturbed areas or stockpiles. 4. Traffic Area Stabilization — A stabilized construction entrance will be located at the point of ingress/egress. 5. Sediment Retention — Surface water collected from disturbed areas of the Site shall be routed through a sediment vault or sediment traps prior to release from the Site. The sediment vault or traps will be installed prior to grading of any contributing area. 6. SurFace Water Control —Interceptor berms or swales shall be installed to control and intercept all surface water from disturbed areas. Surface water controls shall be installed concurrently with and/or immediately following rough grading. 7. Dewatering Control —Will be provided as needed. 8. Dust Control — Dust control shall be provided by spraying exposed soils with water until wet. This is required when exposed soils are dry to the point that wind transport is possible which would impact roadways, drainage ways, surface waters, or neighboring residences. 9. Flow Control — Flow control will be provided by the detention pond. 02015 D.R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 51 Technical Information Report City of Renton SWPPS PLAN DESIGN (PART B) Construction activities that could contribute pollutants to surFace and storm water include the following, with applicable BMP's listed for each item: 1. Storage and use of chemicals: Utilize source control, and soil erosion and sedimentation control practices, such as using only recommended amounts of chemical materials applied in the proper manner; neutralizing concrete wash water, and disposing of excess concrete material only in areas prepared for concrete placement, or return to batch plant; disposing of wash-up waters from water-based paints in sanitary sewer; disposing of wastes from oil-based paints, solvents, thinners, and mineral spirits only through a licensed waste management firm, or treatment, storage, and disposal (TSD} facility. 2. Material delivery and storage: Locate temporary storage areas away from vehicular traffic, near the construction entrance, and away from storm drains. Material Safety Data Sheets (MSDS) should be supplied for all materials stored, and chemicals kept in their original labeled containers. Maintenance, fueling, and repair of heavy equipment and vehicles shall be conducted using spill prevention and control measures. Contaminated surfaces shall be cleaned immediately following any spill incident. Provide cover, containment, and protection from vandalism for all chemicals, liquid products, petroleum products, and other potentially hazardous materials. 3. Building demolition: Protect stormwater drainage system from sediment-laden runoff and loose particles. To the extent possible, use dikes, berms, or other methods to protect overland discharge paths from runoff. Street gutter, sidewalks, driveways, and other paved surFaces in the immediate area of demolition must be swept daily to collect and properly dispose of loose debris and garbage. Spray the minimum amount of water to help control windblown fine particles such as concrete, dust, and paint chips. Avoid excessive spraying so that runoff from the Site does not occur, yet dust control is achieved. Oils must never be used for dust control. 4. Sawcutting: Slurry and cuttings shall be vacuumed during the activity to prevent migration offsite and must not remain on permanent concrete or asphalt paving overnight. Collected slurry and cuttings shall be disposed of in a manner that does not violate ground water or surface water quality standards. The complete CSWPPP can be found in Appendix D of this report. The site plans can be found in the engineering plan set. - ; 02015 D.R.STRONG Consulting Engineers Ina The Enclave at Bridle Ridge Page 52 Technical Information Report City of Renton SECTION IX BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT 1. Bond Quantity Worksheet— attached in Appendix B 2. The Stormwater Facility Summary Sheet is included in this section I 3. Declaration of Covenant— attached in Appendix E , 02015 D.R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 53 Technical Information Report City of Renton STORMWATER FACILITY SUMMARY SHEET Development The Enclave at Bridle Ridge Date May 29, 2014 Location 14038 'l56t" Avenue SE, Renton, lNa�hinqtor� ENGINEER DEVELOPER Name Maher A. Joudi, P.E. Name Firm D. R. STRONG Consulting Firm PNW Holdings LLC Engineers, Inc. Address 620 7t Avenue Address 9675 SE 36 Street, #105 Kirkland, WA 98033 Mercer Island, WA 98040 Phone (425) 827-3063 Phone (206) 588-1147 Developed Site: 8.973 acres Number of lots 31 ' Number of detention facilities on Site: Number of infiltration facilities on Site: vaults vaults 1 pond vaults tanks tanks Flow control provided in regional facility (give - location) ' No flow control required Exemption number , Downstream Drainage Basins Immediate Major Basin Basin Lower Cedar River Cedar River Number & type of water quality facilities on Site: biofiltration swale (regular/wet/ or continuous inflow?) sand filter (basic or large?) sand filter, linear (basic or large?) CONTECH Stormfilter combined detention/WQ vault sand filter �ault (basic or large?) X combined detentionlwetpond stormwater wetland compost filter wetvault (basic or large?) filter strip Wetvault flow dispersion pre-settling pond farm management plan flow-splitter catchbasin landscape management plan oil/water separator (baffle or coalescing plate?) G2015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 54 Technical Information Report City of Renton i catch basin inserts: Manufacturer pre-settling structure: Manufacturer DESIGN INFORMATION INDIVIDUAL BASIN Water Quality design flow Water Quality treated volume Draina e basin(s) Onsite area includes fronta e 8.973 Offsite area Type of Storage Facility Pond Live Stora e Volume (required 98,806 Predev Runoff Rate 2-year 0.249 ' 10- ear 0.435 100- ear 0.724 Develo ed Runoff Rate 2-year 0.150 includes bypass) 10- ear 0.426 100- ear 0.724 Ty e of Restrictor Frop-Tee Size of orifice/restriction No. 1 1.52 No. 2 2.28 No. 3 2.35 02015 D.R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 55 Technical Information Report City of Renton SECTION X OPERATIONS AND MAINTENANCE MANUAL See Appendix C for excerpts from the 2009 King County Surface Water Design Manual with regard to Operations and Maintenance. _ � . . � ; ; I 02015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 56 Technical Information Report City of Renton APPENDICES _ 02015 D.R.STRONG Consulting Engineers Inc. The Enciave at Bridle Ridge Page 57 � Technical Information Report City of Renton APPENDIX "A" LEGAL DESCRIPTION � PARCEL A: PARCEL B CITY OF RENTON LOT LINE ADJUSTMENT LUA14-000250, RECORDED UNDER RECORDING NUMBER 20140606900004, RECORDS OF KING COUNTY, WA. PARCEL B: LOT B OF KING COUNTY TESTAMENTARY DIVISION NO.: L08M0034, RECORDED AUGUST 12, 2008 UNDER RECORDING NO. 20080812900004, KING COUNTY, ' WASHINGTON. BEING NORTHWEST QUARTER OF THE SOUTHWEST QUARTER OF THE SOUTHEAST QUARTER OF SECTION 14, TOWNSHIP 23 NORTH, RANGE 5 EAST, W.M., KING COUNTY WASHINGTON: ' LESS NORTH 100 FEET OF THE WEST 440 FEET. 02015 D.R.STRONG Consulting Engineers Inc. The Enciave at Bridle Ridge Page 58 Technical Information_Report City of Renton APPENDIX "B" BOND QUANTITY WORKSHEET C�2015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 59 Technical Informati�n Report City of Renton Site Improvement Bond Quantity Worksheet Webdate: 12/02/2008 � King Caunty Department of Development & Environmental Services 900 Oakesdale Avenue Southwest Renton, Washington 98057-5212 For alternate formats, call 206-296-6600. 206-296-6600 l7Y 206-296-7217 Pro�ect Name: The Enclave at Bridle Ridge �ate: 5-Jun-14 Location: Renton Project No.: 13117 Activity No.: Note: All prices include labor, equipment, materials, overhead and Clearing greater than or equal to 5,000 board feet of timber? profit. Prices are from RS Means data adjusted for the Seattle area or from local sources if not included in the RS Means database. yes X no If yes, Forest Practice Permit Number: (RCW 76.09) Page 1 of 9 Unit prices updated: 02/12/02 Version: 11/26/2008 Site Improvement Bond Quantity Worksheet Webdate: 12/02/2008 Unit #of Reference# Price Unit Quantity Applications Cost EROSION/SEDIMENT CONTROL Number Backfill&compaction-embankment ESC-1 $ 5.62 CY Check dams,4" minus rock ESC-2 SWDM 5.4.6.3 $ 67.51 Each 20 1 1350 Crushed surfacin 1 1/4" minus ESC-3 WSDOT 9-03.9 3 $ 85.45 CY Ditchin ESC-4 $ 8.08 CY 468 1 3781 Excavation-bulk ESC-5 $ 1.50 CY Fence, silt ESC-6 SWDM 5.4.3.1 $ 1.38 LF 1335 1 1842 Fence,Temporary(NGPE) ESC-7 $ 1.38 LF 1206 1 1664 H droseeding ESC-8 SWDM 5.4.2.4 $ 0.59 SY 33741 1 19907 Jute Mesh ESC-9 SWDM 5.4.22 $ 1.45 SY Mulch, b hand, straw, 3"deep ESC-10 SWDM 5.4.2.1 $ 2.01 SY Mulch, by machine, straw,2"deep ESC-11 SWDM 5.4.2.1 $ 0.53 SY 33741 1 17883 Pipin ,temporary, CPP,6" ESC-12 $ 10.70 LF Pipin ,tempora , CPP, 8" ESC-13 $ 16.10 LF Pipin ,temporary, CPP, 12" ESC-14 $ 20.70 LF 737 1 15256 Plastic covering, 6mm thick, sandbagged ESC-15 SWDM 5.4.2.3 $ 2.30 SY 953 1 2192 Rip Rap, machine laced; slopes ESC-16 WSDOT 9-13.1(2) $ 39.08 CY Rock Construction Entrance, 50'x15'x1' ESC-17 SWDM 5.4.4.1 $ 1,464.34 Each Rock Construction Entrance, 100'x15'x1' ESC-18 SWDM 5.4.4.1 $ 2,928.68 Each 1 1 2929 Sediment ond riser assembly ESC-19 SWDM 5.4.5.2 $ 1,949.38 Each Sediment trap, 5' hi h berm ESC-20 SWDM 5.4.5.1 $ 17.91 LF 80 1 1433 Sed.trap,5'high, riprapped spillway berm section ESC-21 SWDM 5.4.5.1 $ 68.54 LF Seedin , b hand ESC-22 SWDM 5.4.2.4 $ 0.51 SY Soddin , 1"deep, level round ESC-23 SWDM 5.4.2.5 $ 6.03 SY Sodding, 1"deep, slo ed ground ESC-24 SWDM 5.4.2.5 $ 7.45 SY TESC Supervisor ESC-25 $ 74.75 HR Water truck, dust control ESC-26 SWDM 5.4.7 $ 97.75 HR WRITE-IN-ITEMS **** (see paqe 9) Inlet Protection Grate $ 25.00 Each 48 1 1200 ESC SUBTOTAL: $ 69,437.42 30%CONTINGENCY&MOBILIZATION: $ 20,83123 ESC TOTAL: $ 90,268.65 COLUMN: A Page 2 of 9 Unit prices updated: 02/12/02 Version: 11/26/2008 Site Improvement Bond Quantity Worksheet Webdate: 12/02/2008 _ _ Existing Future Public Private Quantity Completed Right-of-Way Right of Way Improvements (Bond Reduction)* &Draina e Facilities Quant. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Com lete Cost GENERALITEMS No. Backfill&Compaction-embankment GI-1 $ 5.62 CY Backfill&Com action-trench GI-2 $ 8.53 CY Clear/Remove Brush,by hand GI-3 $ 0.36 5Y Clearin /Grubbin /Tree Removal GI-4 $ 8,876.16 Acre 1.76 15,622.04 7.04 62,488.17 Excavation-bulk GI-5 $ 1.50 CY 17 25.50 28 42.00 5026 7,539.00 Excavation-Trench GI-6 $ 4.06 CY 502 2,038.12 1240 5,034.40 240 974.40 Fencing,cedar,6'high GI-7 $ 18.55 LF Fencin ,chain link,vin I coated, 6'hi h GI-8 $ 13.44 LF 763 10,254.72 Fencin ,chain link, ate,vinyl coated, 2 GI-9 $ 1,271.81 Each 2 2,543.62 Fencin ,split rail,3'high GI-10 $ 12.12 LF Fill&com act-common barrow GI-11 $ 22.57 CY 307 6,928.99 6503 146,772.71 23942 540,370.94 Fill&compact-gravel base GI-12 $ 25.48 CY Fill&compact-screened topsoil GI-13 $ 37.85 CY Gabion, 12"deep,stone filled mesh GI-14 $ 54.31 SY Gabion, 18"deep,stone filled mesh GI-15 $ 74.85 SY Gabion,36"dee ,stone filled mesh GI-16 $ 132.48 SY Gradin ,fine,by hand GI-17 $ 2.02 SY Gradin ,fine,with rader GI-18 $ 0.95 SY Monuments,3'long GI-19 $ 135.13 Each 2 270.26 5 675.65 Sensitive Areas Sign GI-20 $ 2.88 Each Sodding, 1"deep,sloped ground GI-21 $ 7.46 SY Surve in ,line& rade GI-22 $ 788.26 Da 10 7,882.60 Surveying,lot location/lines GI-23 $ 1,556.64 Acre 8.8 13,698.43 Traffic control crew(2 fla gers) GI-24 $ 85.18 HR 120 10,221.60 Trail,4"chi ed wood GI-25 $ 7.59 SY Trail,4"crushed cinder GI-26 $ 8.33 SY Trail,4"top course GI-27 $ 8.19 SY Wall,retainin ,concrete GI-28 $ 44.16 SF 1550 68,448.00 Wall,rockery GI-29 $ 9.49 SF 2323 22,045.27 Page 3 of 9 SUBTOTAL 19,484.47 271,438.41 632,953.54 Unit prices updated: 02/12/02 "KCC 27A authorizes onlv one bond reduction. Vefslon: 11/26/08 Site Improvement Bond Quantity Worksheet Webdate 12/02/2008 Existing Future Public Private Bond Reduction• Right-of-way Right of Way Improvements 8 Drainage Facilities Quant. Unit Price Unit Quant. Cost Quant. Cosl Quant. Cost Complete Cost ROADIMPROVEMENT No. 'I AC Grinding,4'wide machine<1000sy RI-1 $ 28.00 SY AC Grindin ,4'wide machine 1000-200 RI-2 $ 15.00 SY AC Grindin ,4'wide machine>2000s RI-3 $ 7.00 SY 4835 33,845.00 AC Removal/Disposal/Repair RI-4 $ 67.50 SY 122 8,235.00 Barricade,t e I RI-5 $ 30.03 LF Barricade,t e III(Permanent) RI-6 $ 45.05 LF Curb&Gutter,roiled RI-7 $ 17.00 LF Curb&Gutter,vertical RI-8 $ 12.50 LF 476 5,950.00 2678 33,475.00 Curb and Gutter,demolition and disposa RI-9 $ 18.00 LF Curb,extruded asphalt RI-10 $ 5.50 LF Curb,extruded concrete RI-11 $ 7.00 LF Sawcut,asphalt,3"depth RI-12 $ 1.85 LF 686 1,269.10 Sawcut,concrete,per 1"depth RI-13 $ 1.69 LF Sealant,asphalt RI-14 $ 1.25 LF 1161 1,451.25 Shoulder,AC, (see AC road unit price) RI-15 $ - SY Shoulder, ravel,4"thick RI-16 $ 15.00 SY Sidewalk,4"thick RI-17 $ 35.00 SY 50 1,750.00 1606 56,210.00 Sidewalk,4"thick,demolition and dispos RI-18 $ 29.50 SY Sidewalk,5"thick RI-19 $ 38.50 SY 430 16,555.00 755 29,067.50 Sidewalk,5"thick,demolition and dispos RI-20 $ 37.50 SY Si n,handica RI-21 $ 85.28 Each Striping,per stall RI-22 $ 5.82 Each Stripin ,thermoplastic,(for crosswalk) RI-23 $ 2.38 SF 67 159.46 217 516.46 Striping,4"reflectorized line RI-24 $ 0.25 LF 580 145.00 Page 4 of 9 SUBTOTAL 69,359.81 119,268.96 Unit prices updated: 02/12/02 "KCC 27A authorizes only one bond reduction. Vel'SIOI1: 11/26/08 Site Improvement Bond Quantity Worksheet Webdate: 12/02/2008 Existing Future Public Private Bond Reduction* Right-of-way Right of Way Improvements &Drainage Facilities Quant. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Complete Cost ROAD SURFACING (4"Rock=2.5 base&1.5"top course) For'93 KCRS(6.5"Rock=5"base&1.5"top course) For KCRS'93,(additional 2.5"base)add RS-1 $ 3.60 SY AC Overla , 1.5"AC RS-2 $ 11.25 SY AC Overla ,2"AC RS-3 $ 15.00 SY 4835 72,525.00 AC Road,2",4"rock,First 2500 SY RS-4 $ 21.00 SY AC Road,2",4"rock,Qt .over 2500SY RS-5 $ 19.00 SY AC Road,3",4"rock,First 2500 SY RS-6 $ 23.30 SY 425 9,902.50 2500 58,250.00 AC Road,3",4"rock,Qt .over 2500 SY RS-7 $ 21.00 SY 1894 39,774.00 AC Road,5",First 2500 SY RS-8 $ 27.60 SY AC Road,5",Qty.Over 2500 SY RS-9 $ 25.00 SY AC Road,6",First 2500 SY RS-1 $ 33.10 SY AC Road,6",Qt .Over 2500 SY RS-11 $ 30.00 SY Asphalt Treated Base,4"thick RS-1 $ 20.00 SY 425 8,500.00 4394 87,880.00 Gravel Road,4"rock,First 2500 SY RS-1 $ 15.00 SY Gravel Road,4"rock,Qt .over 2500 SY RS-1 $ 8.50 SY PCC Road,5",no base,over 2500 SY RS-1 $ 27.00 SY PCC Road, 6",no base,over 2500 SY RS-1 $ 25.50 SY Thickened Edge RS-1- $ 8.60 LF 243 2,089.80 Page 5 of 9 SUBTOTAL 90,927.50 187,993.80 Unit prices updated: 02/12/02 "KCC 27A authorizes only one bond reduction. \/Prcinn• 11/�R/f1R Site Improvement Bond Quantity Worksheet Webdate: 12l02/2008 Existing Future Public Private Bond Reduction" Right-of-way Right of Way Improvements &Drainage Facilities Quant. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Complete Cost DRAINAGE (CPP=Corrugated Plastic Pipe, N12 or Equivalent) For Culvert prices, Average of 4'cover was assumed.Assume perforated PVC is same price as solid pipe. Access Road,R/D D-1 $ 21.00 SY 225 4,725.00 Bollards-fixed D-2 $ 240.74 Each Bollards-removable D-3 $ 452.34 Each '(CBs include frame and lid) CB T pe I D-4 $ 1,257.64 Each 4 5,030.56 11 13,834.04 10 12,576.40 CB T e IL D-5 $ 1,433.59 Each 5 7,167.95 CB Type II,48"diameter D-6 $ 2,033.57 Each 4 8,134.28 5 10,167.85 for additional depth over 4' D-7 $ 436.52 FT 7 3,055.64 15 6,547.80 CB Type II,54"diameter D-8 $ 2,192.54 Each for additional depth over 4' D-9 $ 486.53 FT CB T pe II,60"diameter D-10 $ 2,351.52 Each 1 2,351.52 for additional de th over 4' D-11 $ 536.54 FT CB Type II,72"diameter D-12 $ 3,212.64 Each for additional de th over 4' D-13 $ 692.21 FT Through-curb Inlet Framework(Add) D-14 $ 366.09 Each 4 1,464.36 Cleanout, PVC,4" D-15 $ 130.55 Each Cleanout,PVC,6" D-16 $ 174.90 Each 23 4,022.70 Cleanout,PVC,8" D-17 $ 224.19 Each Culvert,PVC,4" D-18 $ 8.64 LF Culvert,PVC,6" D-19 $ 12.60 LF 2035 25,641.00 Culvert,PVC, 8" D-20 $ 13.33 LF Culvert,PVC, 12" D-21 $ 21.77 LF Culvert,CMP,8" D-22 $ 17.25 LF Culvert,CMP, 12" D-23 $ 26.45 LF Culvert,CMP, 15" D-24 $ 32.73 LF Culvert,CMP, 18" D-25 $ 37.74 LF Culvert,CMP,24" D-26 $ 53.33 LF Culvert,CMP,30" D-27 $ 71.45 LF Culvert,CMP,36" D-28 $ 112.11 LF Culvert,CMP,48" D-29 $ 140.83 LF Culvert,CMP,60" D-30 $ 235.45 LF Culvert,CMP,72" D-31 $ 302.58 LF Page 6 of 9 SUBTOTAL 16,220.48 46,258.52 42,240.10 Unit prices updated: 02/12/02 �KCC 27A authorizes onlv one bond reduction. \/arsinn• 11/�F/f1R Site Improvement Bond Quantity Worksheet Webdate: 12/02/2008 Existing Future Public Private Bond Reduction" Right-of-way Right of Way improvements DRAINAGE CONTINUED &Drainage Facilities Quant. No. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Complete Cost Culvert,Concrete,8" D-32 $ 21.02 LF Culvert,Concrete, 12" D-33 $ 30.05 LF Culvert,Concrete, 15" D-34 $ 37.34 LF Cuivert,Concrete, 18" D-35 $ 44.51 LF Cuivert,Concrete,24" D-36 $ 61.07 LF Culvert,Concrete,30" D-37 $ 104.18 LF Culvert,Concrete,36" D-38 $ 137.63 LF Culvert,Concrete,42" D-39 $ 158.42 LF Culvert,Concrete,48" D-40 $ 175.94 LF Culvert,CPP,6" D-41 $ 10.70 LF Culvert,CPP,8" D-42 $ 16.10 LF Culvert,CPP, 12" D-43 $ 20.70 LF 544 11260.8 1331 27551.7 Culvert,CPP, 15" D-44 $ 23.00 LF Culvert,CPP, 18" D-45 $ 27.60 LF 302 8335.2 Culvert,CPP,24" D-46 $ 36.80 LF 167 6145.6 Culvert,CPP,30" D-47 $ 48.30 LF Culvert,CPP,36" D-48 $ 55.20 LF Ditchin D-49 $ 8.08 CY Flow Dispersal Trench (1,436 base+) D-50 $ 25.99 LF French Drain 3'de th D-51 $ 22.60 LF Geotextile,laid in trench, ol ro lene D-52 $ 2.40 SY Infiltration pond testing D-53 $ 74.75 HR Mid-tank Access Riser,48"dia, 6'dee D-54 $ 1,605.40 Each I Pond Overflow S illwa D-55 $ 14.01 SY Restrictor/Oil Se arator, 12" D-56 $ 1,045.19 Each Restrictor/Oil Separator, 15" D-57 $ 1,095.56 Each Restrictor/Oil Separator, 18" D-58 $ 1,146.16 Each 1 1146.16 Riprap,placed D-59 $ 39.08 CY 7 273.56 li Tank End Reducer(36"diameter) D-60 $ 1,000.50 Each Trash Rack, 12" D-61 $ 211.97 Each 1 211.97 Trash Rack,15" D-62 $ 237.27 Each Trash Rack, 18" D-63 $ 268.89 Each 1 268.89 Trash Rack,21" D-64 $ 306.84 Each 1 306.84 Page 7 of 9 SUBTOTAL 11260.8 44239.92 Unit prices updated: 02/12/02 "KCC 27A authorizes only one bond reduction. Version� 11/�F/�R Site Improvement Bond Quantity Worksheet Webdate: 12/02/2008 Existing Future Public Private Bond Reduction" Right-of-way Right of Way Improvements &Drainage Facilities Quant. Unit Price Unil Quant. Price Quant. Cost Quant. Cost Complete Cost PARKING LOT SURFACING N o. 2"AC,2"to course rock&4"borrow PL-1 $ 21.00 SY 2"AC, 1.5" top course&2.5"base cour PL-2 $ 28.00 SY 4"select borrow PL-3 $ 4.55 SY 1.5"top course rock&2.5"base course PL-4 $ 11.41 SY UTILITY POLES & STREET LIGHTING Utilit pole relocation costs must be accompanied by Franchise Utility's Cost Statement Utility Poie(s)Relocation UP-1 $ 10,000.00 Street Light Poles w/Luminaires UP-2 Each WRITE-IN-ITEMS Such as detention/water quality vaults.) No. Utilit Pole Relocation WI-1 $10,000.00 Each 2 20000 Yard Drains WI-2 Each 7 30"DI Sleeve WI-3 LF 12 18"DI Sleeve WI-4 LF 12 WI-5 WI-6 WI-7 WI-8 WI-9 wi-�o SUBTOTAL 20,000.00 SUBTOTAL(SUM ALL PAGES): 227,253.06 669,199.61 675,193.64 30%CONTINGENCY&MOBILIZATION: 68,175.92 200,759.88 202,558.09 GRANDTOTAL: 295,428.98 869,959.50 877,751.73 COLUMN: B C D E Page 8 of 9 Unit prices updated: 02/12/02 *KCC 27A authorizes onlv one bond reduction. �/arcinn� ��i�Finst Site Improvement Bond Quantity Worksheet Webdate: 12/02/2008 Original bond computations prepared by: Name: Maher A. Joudi Date: 5-Jun-14 PE Registration Number: 45232 Tel.#: (425) 827-3063 Firm Name: DR STRONG Consulting Engineers, Inc. aaaress: 620 7th Avenue, Kirkland, WA 98033 Project No: 13117 ROAD IMPROVEMENTS&DRAINAGE FACILITIES FINANCIAL GUARANTEE REQUIREMENTS PERFORMANCE BOND* PUBLIC ROAD&DRAINAGE AMOUNT BOND"AMOUNT MAINTENANCE/DEFECT BOND" REQUIRED AT RECORDING OR Stabilization/Erosion Sediment Control (ESC) (A) $ 90,268.6 TEMPORARY OCCUPANCY••• Existing Right-of-Way Improvements (B) $ 295,429.0 Future Public Right of Way& Drainage Facilities (C) $ 869,959.5 Private Improvements (D) $ 877,751.7 Calculated Quantity Completed (E) $ - Total Right-of Way and/or Site Restoration Bond"/" (A+g) $ 385,697.6 (First$7,500 of bond'shall be cash.) Performance Bond`Amount (A+B+C+D) = TOTAL (T) $ 2,133,408.8 T x 0.30 $ 640,022.7 OR Mmimum on amount is 2000. Reduced PerFormance Bond"`Total*'* (T-E) $ 2,133,408.8 Use larger o x30 0 or(T-E) (g+C)x Maintenance/Defect Bond*Total 0.25= $ 291,347.1 NAME OF PERSON PREPARING BOND'REDUCTION: Date: *NOTE: The word"bond"as used in this document means a financial guarantee acceptable to King County. **NOTE: KCC 27A authorizes right of way and site restoration bonds to be combined when both are required. The restoration requirement shall include the total cost for all TESC as a minimum, not a maximum. In addition,corrective work,both on-and off-site needs to be included. Quantities shall reflect worse case scenarios not just minimum requirements. For example, if a salmonid stream may be damaged,some estimated costs for restoration needs to be reflected in this amount. The 30%contingency and mobilization costs are computed in this quantity. ""*NOTE: Per KCC 27A,total bond amounts remaining after reduction shall not he less than 30%of the original amount(T)or as revised by major design changes. REQUIRED BOND*AMOUNTS ARE SUBJECT TO REVIEW AND MODIFICATION BY DDES Page 9 of 9 Unit prices updated: 02/12/02 Check out the DDES Web site at www.kinpcountv._pov/permits Version: 11/26/08 APPENDIX "C" OPERATIONS AND MAINTENANCE MANUAL 02015 D. R.STRONG Consulting Engineers Ina The Enclave at Bridle Ridge Page 60 Technical Information Report City of Renton APPENDIX A h4AINTENANCE REQUIRE�4ENTS FLOR�CONTROL,CONVEYANCE,AND WQ FACILITIES NO. 1 - DETENTION PONDS Maintenance Defect or Problem Conditions When Maintenance Is Needed Results Expected When Component Maintenance Is Performed Site Trash and debris Any trash and debris which exceed 1 cubic foot Trash and debris cleared from site. per 1,000 square feet(this is about equal to the amount of trash it would take to fill up one standard size o�ce garbage can). In general, there should be no visual evidence of dumping. Noxious weeds Any noxious or nuisance vegetation which may Noxious and nuisance vegetation constitute a hazard to County personnel or the removed according to applicable public. regulations. No danger of noxious vegetation where County personnel or the public might normally be. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil,gasoline,concrete slurries or paint. according to applicable regulations. Source control BMPs implemented'rf appropriate. No contaminants present other than a surface oil film. Grasslgroundcover Grass or groundcover exceeds 18 inches in Grass or groundcover mowed to a height. height no greater than 6 inches. Top or Side Slopes Rodent holes Any evidence of rodent holes if facility is acting Rodents removed or destroyed and of Dam,Berm or as a dam or berm,or any evidence of water dam or berm repaired. Embankment piping through dam or berm via rodent holes. Tree growth Tree growth threatens integrity of slopes,does Trees do not hinder facility not allow maintenance access,or interferes with performance or maintenance maintenance activity. If trees are not a threat or activities. not interFering with access or maintenance,they do not need to be removed. Erosion Eroded damage over 2 inches deep where cause Slopes stabilized using appropriate of damage is still present or where there is erosion control measures. If erosion potential for continued erosion. Any erosion is occurring on compacted slope,a observed on a compacted slope. licensed civil engineer should be consulted to resolve source of erosion. Settlement Any part of a dam,berm or embankment that has Top or side slope restored to design settled 4 inches lower than the design elevation. dimensions. If settlement is significant,a licensed civil engineer should be consulted to determine the cause of the settlement. Storage Area Sediment Accumulated sediment that exceeds 10%of the Sediment cleaned out to designed accumulation designed pond depth. pond shape and depth; pond reseeded if necessary to control erosion. Liner damaged Liner is visible or pond does not hold water as Liner repaired or replaced. (IfApplicable) designed. InIeUOutlet Pipe. Sediment Sediment filling 20%or more of the pipe. InleUoutlet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inleUoutlet No trash or debris in pipes. pipes(inGudes floatables and non-floatables). Damaged Cracks wider than YZ-inch at the joint of the No cracks more than'/.-inch wide at inleUoutlet pipes or any evidence of soil entering thejoint of the inleUoutlet pipe. at the joints of the inlet/outlet pipes. Emergency Tree growth Tree growth impedes flow or threatens stability of Trees removed. OverFlow/Spiliway spillway. Rock missing Only one layer of rock exists above native soil in Spiliway restored to design area five square feet or larger or any exposure of standards. native soil on the spillway. 1l9,�2009 2009 Surface 1�l'ater Design�lanual—Appendix A A-2 APPEI�TDIX A �-iANTENAI�CE REQUIRE1b1E\TS FOR FLOW CONTROL,CONVEYANCE,AND«'Q FACILITIES NO. 4-CONTROL STRUCTURE/FLOW RESTRICTOR Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed Structure Trash and debris Trash or debris of more than'/cubic foot which No Trash or debris blocking or is located immediately in front of the structure potentially blocking entrance to opening or is blocking capacity of the structure by structure. more than 10%. Trash or debris in the structure that exceeds'/, No trash or debris in the structure. the depth from the bottom of basin to invert the lowest pipe into or out of the basin. Deposits of garbage exceeding 1 cubic foot in No condition present which would volume. attract or support the breeding of insects or rodents. Sediment Sediment exceeds 60%of the depth from the Sump of structure contains no battom of the structure to the invert of the lowest sediment. pipe into or out of the structure or the bottom of the FROP-T section or is within 6 inches of the invert of the lowest pipe into or out of the structure or the bottom of the FROP-T section. Damage to frame Corner of frame extends more than 3/inch past Frame is even with curb. and/or top slab curb face into the street(If applicable). Top slab has holes larger than 2 square inches or Top slab is free of holes and cracks. cracks wider than%a inch. Frame not sitting flush on top slab,i.e., Frame is sitting flush on top slab. separation of more than'/<inch of the frame from the top slab. Cracks in walls or Cracks wider than'/z inch and longer than 3 feet, Structure is sealed and structurally bottom any evidence of soil particles entering structure sound. through cracks,or maintenance person judges that structure is unsound. Cracks wider than'/�inch and longer than 1 foot No cracks more than'/,inch wide at at the joint of any inletloutlet pipe or any evidence the joint of inleUoutlet pipe. of soil particles entering structure through cracks. Settlement/ Structure has settled more than 1 inch or has Basin replaced or repaired to design misalignment rotated more than 2 inches out of alignment. standards. Damaged pipe joints Cracks wider than'/z-inch at the joint of the No cracks more than'/4-inch wide at inlet/outlet pipes or any evidence of soil entering the joint of inleUoutlet pipes. the structure at the joint of the inletloutlet pipes. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil,gasoline,concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil fiirn. Ladder rungs missing Ladder is unsafe due to missing rungs, Ladder meets design standards and or unsafe misalignment,rust,cracks,or sharp edges. allows maintenance person safe access. FROP-T Section Damage T section is not securely attached to structure T section securely attached to wall wall and outlet pipe structure should support at and outlet pipe. least 1,000 Ibs of up or down pressure. Structure is not in upright position(allow up to Structure in correct position. 10%fram plumb). Connections to outlet pipe are not watertight or Connections to outlet pipe are water show signs of deteriorated grout. tight;structure repaired or replaced and works as designed. Any holes—other than designed holes—in the Structure has no holes other than structure. designed holes. Cleanout Gate Damaged or missing Cleanout gate is missing. Replace cleanout gate. 2009 Surface Water Design Manual—Appendix A 1 i9.�2009 A-7 APPENDIX A 1�1AINTENA\'CE REQUIRE�-1E�ITS FLO\T��'COv"I'ROL, CONVEYANC�,A\D 1�'Q FACILITIES NO. 4-CONTROL STRUCTURE/FLOW RESTRICTOR Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed Cleanout gate is not watertight. Gate is watertight and works as designed. i Gate cannot be moved up and down by one Gate moves up and down easily and maintenance person. is watertight. Chain/rod leading to gate is missing or damaged. Chain is in place and works as designed. Orifice Plate Damaged or missing Control device is not working properly due to Plate is in place and works as missing,out of place,or bent orifice plate. designed. Obstructions Any trash,debris,sediment,or vegetation Plate is free of all obstructions and blocking the plate. works as designed. Overflow Pipe Obstructions Any trash or debris blocking (or having the Pipe is free of all obstructions and potential of blocking)the o�erflow pipe. works as designed. Deformed or damaged Lip of o�erflow pipe is bent or deformed. OverFlow pipe does not allow lip overflow at an elevation lower than design InIeUOutlet Pipe Sediment Sediment filling 20%or more of the pipe. Inlet/outlet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inleboutlet No trash or debris in pipes. pipes(includes floatables and non-floatables). Damaged Cracks wider than'/2-inch at the joint of the No cracks more than'/<-inch wide at inleUoutlet pipes or any evidence of soil entering the joint of the inleUoutlet pipe. at the joints of the inlet/outlet pipes. Metal Grates Unsafe grate opening Grate with opening wider than'/e inch. Grate opening meets design (If Applicable) standards. Trash and debris Trash and debris that is blocking more than 20% Grate free of trash and debris. of grate surface. footnote to guidelines for disposal Damaged or missing Grate missing or broken member(s)of the grate. Grate is in place and meets design standards. Manhole Cover/Lid Cover/lid not in place Coverllid is missing or only partially in piace. Cover/lid protects opening to Any open structure requires urgent structure. maintenance. Locking mechanism Mechanism cannot be opened by one Mechanism opens with proper tools. Not Working maintenance person with proper tools.Boits cannot be seated. Self-locking co�er/lid does not work. Cover/lid difficuit to One maintenance person cannot remove Cover/lid can be removed and Remo�e coverllid after applying SO Ibs.of lift. reinstalled by one maintenance person. ll9i2009 2009 Surface VVater Design D4anua1—Appendis A a-s APPENDIX A vIAI�1TENANCE REQUIREMEl�'TS FOR FLOW CONTROL,CONVEYAl�'CE,AND Vi�'Q FACILITIES NO. 5-CATCH BASINS AND MANHOLES Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed Structure Sediment Sediment exceeds 60%of the depth from the Sump of catch basin contains no bottom of the catch basin to the invert of the sediment. lowest pipe into or out of the catch basin or is within 6 inches of the invert of the lowest pipe into or out of the catch basin. Trash and debris Trash or debris of more than%z cubic foot which No Trash or debris blocking or is located immediately in front of the catch basin potentially blocking entrance to opening or is blocking capacity of the catch basin catch basin. by more than 10%. Trash or debris in the catch basin that exceeds No trash or debris in the catch basin. '/3 the depth from the bottom of basin to invert the lowest pipe into or out of the basin. Dead animals or vegetation that could generate No dead animals or vegetation odors that could cause complaints or dangerous present within catch basin. gases(e.g.,methane). Deposits of garbage exceeding 1 cubic foot in No condition present which would volume. attract or support the breeding of insects or rodents. Damage to frame Corner of frame extends more than'/.inch past Frame is even with curb. and/or top slab curb face into the street(If applicable). Top slab has holes larger than 2 square inches or Top slab is free of holes and cracks. cracks wider than%4 inch. Frame not sitting flush on top slab,i.e., Frame is sitting flush on top slab. separation of more than'/.inch of the frame from the top slab. Cracks in walls or Cracks wider than YZ inch and longer than 3 feet, Catch basin is sealed and bottom any evidence of soil particles entering catch structurally sound. basin through cracks,or maintenance person judges that catch basin is unsound. Cracks wider than'/2 inch and longer than 1 foot No cracks more than'/4 inch wide at at the joint of any inleUoutlet pipe or any evidence the joint of inlet/outlet pipe. of soil particles entering catch basin through cracks. SettlemenU Catch basin has settled more than 1 inch or has Basin replaced or repaired to design i misalignment rotated more than 2 inches out of alignment. standards. ' Damaged pipe joints Cracks wider than'/rinch at the joint of the No cracks more than%<-inch wide at � inleUoutlet pipes or any evidence of soil entering the joint of inlet/outiet pipes. , the catch basin at the joint of the inleUoutlet pipes. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil,gasoline,concrete slurries or paint. according to applicabie regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. InIeUOutlet Pipe Sediment Sediment filling 20%or more of the pipe. Inlet/outlet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inleUoutlet No trash or debris in pipes. pipes(inGudes floatables and non-floatables). Damaged Cradcs wider than'/z-inch at the joint of the No cracks more than'/.-inch wide at inleUoutlet pipes or any evidence of soil entering the joint of the inleUoutlet pipe. at the joints of the inleUoutlet pipes. 2009 Surface Water Design Manual—Appendix A 1/9/2009 A-9 APPEI�DIX A I��L4INTENANCE KEQUIREI��fENTS FLO��%CONTROL,CONVEYANCE,AND\�'Q FACILITIES NO. 5-CATCH BASINS AND MANHOLES Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is PerFormed Metal Grates Unsafe grate opening Grate with opening wider than'/e inch. Grate opening meets design (Catch Basins) standards. Trash and debris Trash and debris that is blocking more than 20°/a Grate free of trash and debris. of grate surface. footnote to guidelines for disposal Damaged or missing Grate missing or broken member(s)of the grate. Grate is in place and meets design Any open structure requires urgent standards. maintenance. Manhole Cover/Lid Cover/lid not in place Cover/lid is missing or only partiaily in place. Cover/lid protects opening to Any open structure requires urgent structure. maintenance. Locking mechanism Mechanism cannot be opened by one Mechanism opens with proper tools. Not Working maintenance person with proper tools.Bolts cannot be seated. Self-locking cover/lid does not work. Coverllid difficult to One maintenance person cannot remove Cover/lid can be removed and Remove coverllid after applying 80 Ibs.of lift. reinstalled by one maintenance person. 1/9/2009 2009 Surface�'l'ater Design Alanual—:�ppendix A A-10 APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL,CONVEYANCE,AND WQ FACILITIES NO. 6-CONVEYANCE PIPES AND DITCHES Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is PerFormed Pipes Sediment&debris Accumulated sediment or debris that exceeds Water flows freely through pipes. accumulation 20%of the diameter of the pipe. Vegetation/roots Vegetation/roots that reduce free movement of Water flows freely through pipes. waterthrough pipes. Contaminants and Any evidence of contaminants or pollution such Materiais removed and disposed of pollution as oil,gasoline,concrete slurries or paint. according to applicable regulations. Source control BMPs implemented'rf appropriate. No contaminants , present other than a surtace oil film. Damage to protective Protective coating is damaged;rust or corrosion Pipe repaired or replaced. coating or corrosion is weakening the structural integrity of any part of pipe. Damaged Any dent that decreases the cross section area of Pipe repaired or replaced. pipe by more than 20%or is determined to have weakened structural integrity of the pipe. Ditches Trash and debris Trash and debris exceeds 1 cubic foot per 1,000 Trash and debris cleared from square feet of ditch and slopes. ditches. Sediment Accumulated sediment that exceeds 20%of the Ditch cleaned/flushed of all sediment accumulation design depth. and debris so that it matches design. Noxious weeds Any noxious or nuisance vegetation which may Noxious and nuisance vegetation constitute a hazard to County personnel or the removed according to applicable public. regulations. No danger of noxious vegetation where County personnel or the public might normally be. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of poilution as oil,gasoline,concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Vegetation Vegetation that reduces free movement of water Water flows freely through ditches. through ditches. Erosion damage to Any erosion observed on a ditch slope. Slopes are not eroding. slopes Rock lining out of One layer or less of rock exists above native soil Replace rocks to design standards. place or missing(If area 5 square feet or more,any exposed native Applicable) soil. �(iCi�i ��_;i��.i��r 11�itcr U�>�:�i� �l,:i��,i_il ::�-�n.li�.\ I 'i '�;i��) �-I l APPENDIX A NIAINTENANCE REQUIREViENTS FLO�V CONTROL,C0�IVEYANCE,AI�D\�'Q FACILITI�S NO. 9- FENCING Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed Site Erosion or holes Erosion or holes more than 4 inches high and 12- No access under the fence. under fence 18 inches wide permitting access through an opening under a fence. Wood Posts,Boards Missing or damaged Missing or broken boards,post out of plumb by No gaps on fence due to missing or and Cross Members parts more than 6 inches or cross members broken broken boards,post plumb to within 1'/Z inches,cross members sound. Weakened by rotting Any part showing structural deterioration due to AII parts of fence are structurally or insects rotting or insect damage sound. Damaged or failed Concrete or metai attachments deteriorated or Post foundation capable of post foundation unable to support posts. supporting posts even in strong wind. Metal Posts,Rails Damaged parts Post out of plumb more than 6 inches. Post plumb to within 1'/�inches. and Fabric Top rails bent more than 6 inches. Top rail free of bends greater than 1 inch. Any part of fence(including post,top rails,and Fence is aligned and meets design fabric)more than 1 foot out of design alignment. standards. Missing or loose tension wire. Tension wire in place and holding fabric. Deteriorated paint or Part or parts that have a rusting or scaling Structurally adequate posts or parts protective coating condition that has affected structural adequacy. with a uniform protective coating. Openings in fabric Openings in fabric are such that an 8-inch Fabric mesh openings within 50%of diameter ball could fit through. grid size. 1/9/2009 2009 Surface Water Design Manual—Appendix A A-14 APPEI�'DIX A MAIi�1TEI�TANCE REQUIREMENTS FOR FLOW CONTROL,CONVEYANCE;AND WQ FACILITIES NO. 10-GATESIBOLLARDSlACCESS BARRIERS Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed Chain Link Fencing Damaged or missing Missing gate. Gates in place. Gate members Broken or missing hinges such that gate cannot Hinges intact and lubed.Gate is be easily opened and closed by a maintenance working freely. person. Gate is out of plumb more than 6 inches and Gate is aligned and vertical. more than 1 foot out of design alignment. Missing stretcher bar,stretcher bands,and ties. Stretcher bar,bands,and ties in place. Locking mechanism Locking device missing,no-functioning or does Locking mechanism prevents does not lock gate not link to all parts. opening of gate. Openings in fabric Openings in fabric are such that an 8-inch Fabric mesh openings within 50%of diameter ball could fit through. grid size. Bar Gate Damaged or missing Cross bar does not swing open or closed,is Cross bar swings fully open and cross bar missing or is bent to where it does not prevent closed and prevents vehicle access. � vehicle access. Locking mechanism Locking device missing,no-functioning or does Locking mechanism prevents does not lodc gate not link to all parts. opening of gate. Support post Support post does not hold cross bar up. Cross bar held up preventing vehicle damaged access into facility. Bollards Damaged or missing Bollard broken,missing,does not fit into support No access for motorized vehicles to hole or hinge broken or missing. get into facility. Does not lock Locking assembly or lock missing or cannot be No access for motorized vehicles to attached to lock bollard in place. get into facility. Boulders Dislodged Boulders not located to prevent motorized vehicle No access for motorized vehicles to access. get into facility. Circumvented Motorized vehicles going around or between No access for motorized vehicles to boulders. get into facility. 2009 Surface Water Design Manual—Appendix A 1�9%2009 A-1� APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL,CONVEYANCE,AND WQ FACILITIES NO. 11 -GROUNDS (LANDSCAPING) Maintenance Defect or Problem Conditions When Maintenance is Needed Resuks Expected When I Component Maintenance is Performed Site Trash or litter Any trash and debris which exceed 1 cubic foot Trash and debris cleared from site. per 1,000 square feet(this is about equal to the amount of trash it would take to fill up one standard size office garbage can). In general, there should be no visual evidence of dumping. Noxious weeds Any noxious or nuisance vegetation which may Noxious and nuisance vegetation constitute a hazard to County personnel or the removed according to applicabie public. regulations. No danger of noxious vegetation where County personnel or the public might normally be. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil,gasoline,concrete slurries or paint. according to applicable regulations. Source controi BMPs implemented if appropriate. No contaminants , present other than a surface oil film. ' Grass/groundcover Grass or groundcover exceeds 18 inches in Grass or groundcover mowed to a height. height no greater than 6 inches. Trees and Shrubs Hazard Any tree or limb of a tree identified as having a No hazard trees in facility. potential to fall and cause property damage or threaten human life. A hazard tree identified by a qualified arborist must be removed as soon as possible. Damaged Limbs or parts of trees or shrubs that are split or Trees and shrubs with less than 5°/a '_ broken which affect more than 25%of the total of total foliage with split or broken foliage of the tree or shrub. limbs. Trees or shrubs that have been blown down or No blown down vegetation or knocked over. knocked over vegetation. Trees or shrubs free of injury. Trees or shrubs which are not adequately Tree or shrub in place and supported or are leaning over,causing exposure adequately supported;dead or of the roots. diseased trees removed. 1/9/2009 2009 Surface�Vater Design NSanual—Appendix A A-16 APPENDIX A MAIN"I'ENAI�CE REQUIREMENTS FOR FLOW CONTROL,CONVEYANCE,AND WQ FACILITIES NO. 12-ACCESS ROADS Maintenance Defect or Problem Condition When Maintenance is Needed Results Eupected When Component Maintenance is Performed Site Trash and debris Trash and debris exceeds 1 cubic foot per 1,000 Roadway drivable by maintenance square feet(i.e.,trash and debris would fill up vehicles. one standards size garbage can). Debris which could damage vehicle tires or Roadway drivable by maintenance prohibit use of road. vehicles. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil,gasoline,concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Blocked roadway Any obstruction which reduces clearance above Roadway overhead clear to 14 feet road surface to less than 14 feet. high. Any obstruction restricting the access to a 10-to At least 12-foot of width on access 12 foot width for a distance of more than 12 feet road. or any point restricting access to less than a 10 foot width. Road Surface Erosion,settlement, Any surFace defect which hinders or prevents Road drivable by maintenance potholes,soft spots, maintenance access. vehicles. ruts Vegetation on road Trees or other vegetation prevent access to Maintenance vehicles can access surface facility by maintenance vehicles. facility. Shoulders and Erosion Erosion within 1 foot of the roadway more than 8 Shoulder free of erosion and Ditches inches wide and 6 inches deep. matching the surrounding road. Weeds and brush Weeds and brush exceed 18 inches in height or Weeds and brush cut to 2 inches in hinder maintenance access. height or cleared in such a way as to allow maintenance access. Modular Grid Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of Pavement pollution as oil,gasoline,concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Damaged or missing Access surface compacted because of broken on Access road surface restored so missing modular block. road infiltrates. 2009 Surface�'��ater Design I��anual—Appendix A 1/9/2009 A-17 APPENDIX A MAINTENANCE REQUIREMENTS FOR FLO�'J CONTROL,CONVEYANCE,AND WQ FACILITIES NO. 16-WETPOND I Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When II Component Maintenance Is Performed Site Trash and debris Any trash and debris accumulated on the Wetpond site free of any trash or wetpond site. debris. Noxious weeds Any noxious or nuisance vegetation which may Noxious and nuisance vegetation constitute a hazard to County personnel or the removed according to applicable public. regulations. No danger of noxious vegetation where County personnel or the public might normally be. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil,gasoline,concrete sfurries or paint. according to applicable regutations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Grass/groundcover Grass or groundcover exceeds 18 inches in Grass or groundcover mowed to a height. height no greater than 6 inches. Side Slopes of Dam, Rodent holes Any evidence of rodent holes if facility is acting Rodents removed or destroyed and Berm,internal berm as a dam or berm,or any evidence of water dam or berm repaired. or Embankment piping through dam or berm via rodent holes. Tree growth Tree growth threatens integrity of dams,berms or Trees do not hinder facility slopes,does not allow maintenance access,or perFormance or maintenance interferes with maintenance activity. If trees are activities. not a threat to dam,berm or embankment integrity,are not interfering with access or maintenance or leaves do not cause a plugging problem they do not need to be removed. Erosion Eroded damage over 2 inches deep where cause Slopes stabilized using appropriate of damage is still present or where there is erosion control measures. If erosion potential for continued erosion. Any erosion is occurring on compacted slope, a observed on a compacted slope. licensed cNil engineer should be consulted to resolve source of erosion. Top or Side Slopes Settlement Any part of a dam,berm or embankment that has Top or side siope restored to design of Dam,Berm, settled 4 inches lower than the design elevation. dimensions. If settlement is intemal berm or significant,a licensed civil engineer Embankment should be consulted to determine the cause of the settlement. Irregular surface on Top of berm not uniform and level. Top of berm graded to design internal berm elevation. Pond Areas Sediment Accumulated sediment that exceeds 10%of the Sediment cleaned out to designed accumulation(except designed pond depth. pond shape and depth. first wetpool cell) Sediment Sediment accumulations in pond bottom that Sediment storage contains no accumulation(first exceeds the depth of sediment storage(1 foot) sediment. wetpool cell) plus 6 inches. Liner damaged(If Liner is visible or pond does not hold water as Liner repaired or replaced. Applicable) designed. Water level(first First cell empty,doesn't hold water. Water retained in first cell for most of wetpool cell) the year. Algae mats(first Algae mats develop over more than 10%of the Algae mats removed(usually in the wetpool cell) water surface should be removed. late summer before Fall rains, especially in Sensitive Lake Protection Areas.) Gravity Drain Inoperable valve Valve will not open and close. Valve opens and closes normally. I Valve won't seal Valve does not seal completely. Valve completely seals closed. Emergency Overflow Tree growth Tree growth impedes flow or threatens stability of Trees removed. Spillway spillway. 2009 Surface VVater Desi�n�-tanual—Appendix A 1/9/2009 A-21 APPENDIX A MAINTENA�ICE REQUIREMENTS FLOW CONTROL,CONVEYANCE,AND WQ FACILITIES NO. 16-WETPOND Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance Is Performed Rock missing Only one layer of rock exists above native soil in Spiliway restored to design area five square feet or larger,or any exposure of standards. native soil at the top of out flow path of spillway. Rip-rap on inside slopes need not be replaced. InIeUOutlet Pipe Sediment Sediment filling 20%or more of the pipe. InleUoutlet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inleUoutlet No trash or debris in pipes. pipes(includes floatables and non-floatables). Damaged Cracks wider than'/2-inch at the joint of the No cracks more than%4-inch wide at inleUoutlet pipes or any evidence of soil entering the joint of the inleUoutlet pipe. at the joints of the inleUoutlet pipes. � r 1i9,�2009 2009 Surface«'ater Design I�lanual—Appendix A A-22 APPENDIX "D" CSWPPP �2015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 61 Technical Information Report City of Renton STORMWATER POLLUTION PREVENTION PLAN For THE ENCLAVE AT BRIDLE RIDGE Prepared For Northwest Regional Office 3190 160t" Avenue SE Bellevue, WA 98008-5452 425-649-7000 Owner Developer Operator/Contractor , PNW Holdings LLC PNW Holdings LLC Maher A. Joudi, P.E. 9675 SE 36th Street, Suite 105 9675 SE 36th Street Suite 105 620 7th Avenue Mercer Island, Washington Mercer Island, Washington Kirkland, Washington 98033 98040 98040 Project Site Location 14038 156th Avenue SE, Renton, Washington Certified Erosion and Sediment Control Lead Justin Lagers 253.405.5587 SWPPP Prepared By D.R. Strong Consulting Engineers, Inc. 620 7th Avenue Kirkland, Washington 98033 MaherA. Joudi, P.E., Senior Project Engineer SWPPP Preparation Date June 23, 2014 Approximate Project Construction Dates Start Date: 9/1/15 End Date: 2/27/16 O 2014 D. R. STRONG Consulting Engineers Inc. STORMWATER POLLUTION PREVENTION PLAN TABLE OF CONTENTS 1.0 INTRODUCTION .......................................................................................................1 2.0 SITE DESCRIPTION .................................................................................................3 2.1 Existing Conditions............................................................................................3 2.2 Proposed Construction Activities.......................................................................3 ' ''. 3.0 CONSTRUCTION STORMWATER BMPS................................................................6 3.1 The 12 BMP Elements.......................................................................................6 3.1.1 Element #1 — Mark Clearing Limits.............................................................6 3.1.2 Element #2 — Establish Construction Access .............................................6 ` 3.1.3 Element #3 — Control Flow Rates...............................................................7 3.1.4 Element#4 — Install Sediment Controls .....................................................7 3.1.5 Element#5 — Stabilize Soils.......................................................................8 _ 3.1.6 Element#6 — Protect Slopes......................................................................9 3.1.7 Element#7 — Protect Drain Inlets.............................................................10 3.1.8 Element#8 — Stabilize Channels and Outlets ..........................................10 3.1.9 Element#9 — Control Pollutants...............................................................11 3.1.10 Element#10 — Control Dewatering...........................................................12 3.1.11 Element#11 — Maintain BMPs .................................................................12 3.1.12 Element#12 — Manage the Project ..........................................................12 3.2 Site Specific BMPs..........................................................................................14 3.3 Additional Advanced BMPs .............................................................................14 4.0 CONSTRUCTION PHASING AND BMP IMPLEMENTATION................................15 5.0 POLLUTION PREVENTION TEAM.........................................................................16 5.1 Roles and Responsibilities ..............................................................................16 5.2 Team Members ...............................................................................................16 6.0 SITE INSPECTIONS AND MONITORING...............................................................17 6.1 Site Inspection.................................................................................................17 6.1.1 Site Inspection Frequency........................................................................17 6.1.2 Site Inspection Documentation.................................................................17 6.2 Stormwater Quality Monitoring ........................................................................18 6.2.1 Turbidity Sampling .........................................................................................18 6.2.2 pH Sampling ..................................................................................................18 6.2.3 Temperature Monitoring ...........................................................................19 7.0 REPORTING AND RECORDKEEPING ..................................................................20 7.1 Recordkeeping ................................................................................................20 7.1.1 Site Log Book...........................................................................................20 7.1.2 Records Retention....................................................................................20 O 20154 D. R.STRONG Consulting Engineers Inc. Page i of ii Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 7.1.3 Access to Plans and Records...................................................................20 7.1.4 Updating the SWPPP...............................................................................20 7.2 Reporting.........................................................................................................21 7.2.1 Discharge Monitoring Reports..................................................................21 7.2.2 Notification of Noncompliance..................................................................21 7.2.3 Permit Application and Changes ..............................................................21 Appendices AppendixA — Site Plans ................................................................................................22 Appendix B — Construction BMPs..................................................................................23 Appendix C —Alternative BMPs.....................................................................................24 Appendix D — General Permit........................................................................................25 Appendix E — Site Inspection Forms (And Site Log) ......................................................26 Appendix F — Engineering Calculations.................................................. .....33 .................. Appendix A Site Plans • Vicinity map (with all discharge points) • Site plan with TESC measures Appendix B Construction BMPs • Possibly reference in BMPs, but likely it will be a consolidated list so that the applicant can photocopy from the list from the SWMM. Appendix C Alternative Construction BMP list • List of BMPs not selected, but can be referenced if needed in each of the 12 elements Appendix D General Permit Appendix E Site Log and Inspection Forms Appendix F Engineering Calculations • Flows, ponds, etc... �20154 D.R. STRONG Consulting Engineers Inc. Page ii of ii , Stormwater Pollution Prevention Plan The Encla�e at Bridle Ridge June 23,2014 i Stormwater Pollution Prevention Plan 1 .0 INTRODUCTION This Stormwater Pollution Prevention Plan (SWPPP) has been prepared as part of the NPDES stormwater permit requirements for the The Enclave at Bridle Ridge (The Enclave) residential project located in Renton, Washington. The site is located at 14038 156th Avenue SE, Renton, Washington. The proposed development consists of the construction of 31 single-family dwelling units, roadway improvements, stormwater detention facility, and landscaping on 8.795 acres. Construction activities will include, grading, roadway construction, utility installation and home construction. The purpose of this SWPPP is to describe the proposed construction activities and all temporary and permanent erosion and sediment control (TESC) measures, pollution prevention measures, inspection/monitoring activities, and recordkeeping that will be implemented during the proposed construction project. The objectives of the SWPPP are to: 1. Implement Best Management Practices (BMPs) to prevent erosion and sedimentation, and to identify, reduce, eliminate or prevent stormwater contamination and water pollution from construction activity. 2. Prevent violations of surface water quality, ground water quality, or sediment management standards. 3. Prevent, during the construction phase, adverse water quality impacts including impacts on beneficial uses of the receiving water by controlling peak flow rates and volumes of stormwater runoff at the Permittee's outfalls and downstream of the outfalls. This SWPPP was prepared using the Ecology SWPPP Template downloaded from the Ecology website on July 2, 2005. This SWPPP was prepared based on the requirements set forth in the Construction Stormwater General Permit, Stormwater Management Manual for Western Washington (SWMMIIWI! 2005) and in the Stormwater Management Manual for Eastern Washington (SWMMEW 2004). The report is divided into seven main sections with several appendices that include stormwater related reference materials. The topics presented in the each of the main sections are: • Section 1 — INTRODUCTION. This section provides a summary description of the project, and the organization of the SWPPP document. • Section 2 — SITE DESCRIPTION. This section pro�ides a detailed description of the existing site conditions, proposed construction activities, and calculated stormwater flow rates for existing conditions and post— construction conditions. • Section 3 — CONSTRUCTION BMPs. This section provides a detailed description of the BMPs to be implemented based on the 12 required elements of the SWPPP (SWMMEW 2004). �2015 D. R.STRONG Consulting Engineers Inc. Page 1 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 Stormwater Poliution Prevention Plan • Section 4 — CONSTRUCTION PHASING AND BMP IMPLEMENTATION. This section provides a description of the timing of the BMP implementation in relation to the project schedule. • Section 5 — POLLUTION PREVENTION TEAM. This section identifies the appropriate contact names (emergency and non-emergency), monitoring personnel, and the onsite temporary erosion and sedimentation control inspector • Section 6 — INSPECTION AND MONITORING. This section provides a description of the inspection and monitoring requirements such as the parameters of concern to be monitored, sample locations, sample frequencies, and sampling methods for all stormwater discharge locations from the site. • Section 7 — RECORDKEEPING. This section describes the requirements for documentation of the BMP implementation, site inspections, monitoring results, and changes to the implementation of certain BMPs due to site factors experienced during construction. Supporting documentation and standard forms are provided in the following Appendices: Appendix A — Site plans Appendix B — Construction BMPs Appendix C —Alternative Construction BMP list Appendix D — General Permit Appendix E — Site Log and Inspection Forms Appendix F — Engineering Calculations O 2015 D. R.STRONG Consulting Engineers Inc. Page 2 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 Stormwater Pollution Prevention Plan 2.0 SITE DESCRIPTION 2.1 Existing Conditions Total existing Site area is approximately 383,127 s.f. (8.795 ac). Total proposed Project area is 390,865 s.f. (8.973 ac) which includes 7,738 s.f. (0.178 ac) for the right-of-way frontage improvements on 156th. The Parcels are currently de�eloped with one single- family residence, out buildings and a gravel driveway. The remainder of the Site is pasture, scotch broom, and scattered trees. The 8.795 acres are situated on a slope that discharges runoff into one Threshold Discharge Area (TDA). However, the Site appears to have two Natural Discharge Areas (NDA). The Site's second natural discharge point is east of NDA 1. Runoff exits the Site as sheet flow and converges with NDA 1 at the southwest corner of the Site. Runoff outlets into Stewart Creek and eventually discharges into Lake Washington. For the purpose of hydrologic calculations, the entire Site is modeled as till forest. 2.2 Proposed Construction Activities The applicant has gained approval to subdivide 8.795 acres into 31 single-family residential lots (Project), with lot sizes ranging from approximately 8,050 to 12,566 s.f. All existing improvements will be demolished or removed during plat construction. The proposed impervious surface area will include a new subdivision road right-of-way with 26 feet of pavement, vertical curb, gutter, 8-foot planter and a 5-foot sidewalk (53-foot right of way) as well as offsite half-street improvements along 156th Avenue SE. The proposed right-of-way improvements total approximately 84,267 s.f. The 31 single- family residences and their driveways combined will create approximately 61,230 s.f. of impervious area (reduced from maximum allowable, see next paragraph for details). Post-developed impervious areas including rights-of-way, sidewalks, roofs, driveways and site frontage improvements total approximately 110,642 s.f. (includes Bypass area). The remainder of the Project will be modeled as till grass with the total being approximately 89,733 s.f. , Per the 2009 King County SurFace Water Design Manual (Manual), Appendix C, each lot within a new subdivision is required to mitigate for impervious surface area equal to 10% of the lot area. Per Figure C.1.3.A, Flow Control BMP Flowchart, the Project will utilize Basic Dispersion with the use of splash blocks. Two splash blocks mitigating a total of 1,400 s.f. of impervious area, will be installed with each residence. This shall mitigate for 11.14% to 17.39% of impervious area for each lot, thus accommodating flow control BMP requirements. See table below for lot area and percent impervious mitigated per lot. O 2015 D. R.STRONG Consulting Engineers Inc. Page 3 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 Stormwater Pollution Prevention Plan ROOF AREA ROUTED TO PERCENT I MPERVIOUS LOT NO. LOT AREA(S.F.) SPLASH BLOCK(S.F.) MITIGATED 1 8190 1400 17.09 2 8190 1400 17.09 3 8986 1400 15.58 4 12566 1400 11.14 5 8346 1400 16.77 6 8050 1400 17.39 7 8052 1400 17.39 8 8052 1400 17.39 9 8052 1400 1739 10 8052 1400 17.39 11 8051 1400 17.39 12 10479 1400 13.36 13 11170 1400 12.53 14 9266 1400 15.11 15 8398 1400 16.67 16 8625 1400 16.23 17 8050 1400 17.39 18 8050 1400 17.39 19 9237 1400 15.16 20 9252 1400 15.13 21 8050 1400 17.39 22 8050 1400 17.39 23 8050 1400 17.39 24 8683 1400 16.12 25 9533 1400 14.69 26 9168 1400 15.27 27 8683 1400 16.12 28 8050 1400 17.39 29 8050 1400 17.39 30 8050 1400 17.39 31 9525 1400 14.70 The Project is required to provide Basic Water Quality treatment and Level 3 Flow Control, per the 2009 KCSWDM (Manual). All surface water runoff from impervious surfaces will be collected and conveyed to a storm detention/water quality pond located in Tract "A". The facility will be sized using 4,000 s.f. of impervious area per lot per section 3.2.2. No flow control credit was taken for the use of splash blocks with regard to facility sizing. No restricted footprint credit is proposed. The following summarizes details regarding site areas: • Total site developable area: 8.795 acres • Percent impervious area before construction: 0.5 % O 2015 D. R.STRONG Consulting Engineers Inc. Page 4 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 Stormwater Pollution Prevention Plan • Percent impervious area after construction: 52.2 % • Disturbed area during construction: 8.973 acres • Disturbed area that is characterized as impervious (i.e., access roads, staging, parking): 1.817 acres TDA • 2-year stormwater runoff peak flow prior to construction (existing): 0.249 cfs • 10-year stormwater runoff peak flow prior to construction (existing): 0.435 cfs • 2-year stormwater runoff peak flow during construction: 1.520 cfs • 10-year stormwater runoff peak flow during construction: 1.840 cfs • 2-year stormwater runoff peak flow after construction: 0.125 cfs • 10-year stormwater runoff peak flow after construction: 0.432 cfs i_ All stormwater flow calculations are provided in Appendix F. r , O 2015 D. R.STRONG Consulting Engineers Inc. Page 5 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 � Stormwater Pollution Prevention Plan 3.0 CONSTRUCTION STORMWATER BMPS 3.1 The 12 BMP Elements 3.1.1 Element#1 — Mark Clearing Limits To protect adjacent properties and to reduce the area of soil exposed to construction, the limits of construction will be clearly marked before land-disturbing activities begin. Trees that are to be preserved, as well as all sensitive areas and their buffers, shall be clearly delineated, both in the field and on the plans. In general, natural vegetation and native topsoil shall be retained in an undisturbed state to the maximum extent possible. The BMPs relevant to marking the clearing limits that will be applied for this project include: • High Visibility Plastic or Metal Fence (BMP C103) The plastic fence will be placed around the perimeter of the developable area of the Site. BMP will be implemented at the start of construction. Alternate BMPs for marking clearing limits are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. 3.1.2 Element#2 — Establish Construction Access Construction access or activities occurring on unpaved areas shall be minimized, yet where necessary, access points shall be stabilized to minimize the tracking of sediment onto public roads, and wheel washing, street sweeping, and street cleaning shall be employed to prevent sediment from entering state waters. All wash wastewater shall be controlled on site. The specific BMPs related to establishing construction access that will be used on this project include: • Stabilized Construction Entrance (BMP C105) • Construction Road/Parking Area Stabilization (BMP C107) A Stabilized Construction Entrance will be placed at the intersection of the proposed "Road B" and 156th Avenue SE on the existing driveway. This BMP will be implemented at the start of construction. Construction Road and Parking Area Stabilization will occur along the road into the site and in staging areas where parking of equipment will occur. This will occur as the project goes along. Alternate construction access BMPs are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective �2015 D. R.STRONG Consulting Engineers Inc. Page 6 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 Stormwater Pollution Prevention Plan or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. 3.1.3 Element#3 — Control Flow Rates In order to protect the properties and waterways downstream of the project site, stormwater discharges from the site will be controlled. The specific BMPs for flow control that shall be used on this project include: • Detention Pond A detention pond will be installed in Tract A. The pond will be constructed and used as a sedimentation device during construction. Alternate flow control BMPs are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. The project site is located west of the Cascade Mountain Crest. As such, the project must comply with Minimum Requirement 7 (Ecology 2005). In general, discharge rates of stormwater from the site will be controlled where increases in impervious area or soil compaction during construction could lead to downstream erosion, or where necessary to meet local agency stormwater discharge requirements (e.g. discharge to combined sewer systems). 3.1.4 Element#4— Install Sediment Controls All stormwater runoff from disturbed areas shall pass through an appropriate sediment removal BMP before leaving the construction site or prior to being discharged to an infiltration facility. The specific BMPs to be used for controlling sediment on this project include: • Silt Fence (BMP C233) • Storm Drain Inlet Protection (BMP C220) • Interceptor Swale (BMP C200) I • Detention Pond Silt fence will be installed around the perimeter of the Site in areas where runoff could sheet-flow offsite. This BMP will be installed at the start of construction. Storm Drain Inlet Protection will be installed on all newly constructed catch basins throughout the site as well as the existing catch basins in 156th Avenue SE. The O 2015 D.R.STRONG Consulting Engineers Inc. Page 7 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 Stormwater Pollution Prevention Plan existing catch basin protection will be installed at the start of construction, and protection for the newly constructed catch basins will occur as they are installed. The interceptor swales will be installed during site grading. The detention pond will be installed and used for sedimentation at the commencement of construction. Alternate sediment control BMPs are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues '�, that may cause a violation(s) of the NPDES Construction Stormwater permit (as ' provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly ' initiate the implementation of one or more of the alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. In addition, sediment will be removed from paved areas in and adjacent to construction work areas manually or using mechanical sweepers, as needed, to minimize tracking of sediments on vehicle tires away from the site and to minimize washoff of sediments from adjacent streets in runoff. Whenever possible, sediment laden water shall be discharged into onsite, relatively level, vegetated areas (BMP C240 paragraph 5, page 4-102). In some cases, sediment discharge in concentrated runoff can be controlled using permanent stormwater BMPs (e.g., infiltration swales, ponds, trenches). Sediment loads can limit the effectiveness of some permanent stormwater BMPs, such as those used for infiltration or biofiltration; however, those BMPs designed to remove solids by settling (wet ponds or detention ponds) can be used during the construction phase. When permanent stormwater BMPs will be used to control sediment discharge during construction, the structure will be protected from excessive sedimentation with adequate erosion and sediment control BMPs. Any accumulated sediment shall be removed after construction is complete and the permanent stormwater BMP will be restabilized with vegetation per applicable design requirements once the remainder of the site has been stabilized. The following BMPs will be implemented as end-of-pipe sediment controls as required to meet permitted turbidity limits in the site discharge(s). Prior to the implementation of these technologies, sediment sources and erosion control and soil stabilization BMP efforts will be maximized to reduce the need for end-of-pipe sedimentation controls. • Construction Stormwater Filtration (BMP C251) • Construction Stormwater Chemical Treatment (BMP C 250) (implemented only with prior written approval from Ecology). 3.1.5 Element#5 — Stabilize Soils Exposed and unworked soils shall be stabilized with the application of effective BMPs to prevent erosion throughout the life of the project. The specific BMPs for soil stabilization that shall be used on this project include: O 2015 D.R.STRONG Consulting Engineers Inc. Page 8 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 Stormwater Pollution Prevention Plan • Temporary and Permanent Seeding (BMP C120) ' • Plastic Covering (BMP C123) • Dust Control (BMP C140) Permanent Seeding will occur as grading is completed. All stabilized sections will be seeded and vegetated. Plastic Covering will occur throughout the site as deemed necessary by the contractor and CESCL. Dust Control will occur throughout the site as deemed necessary by the contractor and CESCL. Alternate soil stabilization BMPs are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the Generat NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. The project site is located west of the Cascade Mountain Crest. As such, no soils shall remain exposed and unworked for more than 7 days during the dry season (May 1 to September 30) and 2 days during the wet season (October 1 to April 30). Regardless of the time of year, all soils shall be stabilized at the end of the shift before a holiday or weekend if needed based on weather forecasts. In general, cut and fill slopes will be stabilized as soon as possible and soil stockpiles will be temporarily covered with plastic sheeting. All stockpiled soils shall be stabilized from erosion, protected with sediment trapping measures, and where possible, be located away from storm drain inlets, waterways, and drainage channels. 3.1.6 Element#6 — Protect Slopes All cut and fill slopes will be designed, constructed, and protected in a manner than minimizes erosion. The following specific BMPs will be used to protect slopes for this project: • Temporary and Permanent Seeding (BMP C120) • Check Dams (BMP C207) Permanent Seeding will occur throughout the site as slopes are stabilized. Checks Dams will be installed every 50' as shown on the plan. Alternate slope protection BMPs are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly O 2015 D. R.STRONG Consulting Engineers Inc. Page 9 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 Stormwater Poliution Prevention Plan initiate the implementation of one or more of the alternative BMPs listed in Appendix C I after the first sign that existing BMPs are ineffective or failing. , 3.1.7 Element#7 — Protect Drain Inlets All storm drain inlets and culverts made operable during construction shall be protected to prevent unfiltered or untreated water from entering the drainage conveyance system. However, the first priority is to keep all access roads clean of sediment and keep street wash water separate from entering storm drains until treatment can be provided. Storm Drain Inlet Protection (BMP C220) will be implemented for all drainage inlets and culverts that could potentially be impacted by sediment-laden runoff on and near the project site. The following inlet protection measures will be applied on this project: Drop Inlet Protection • Catch Basin Filters Storm Drain Inlet Protection will be installed on all newly constructed catch basins throughout the site as well as the existing catch basins in 156th Avenue SE. The existing catch basin protection will be installed at the start of construction, and protection for the newly constructed catch basins will occur as they are installed. The outlet catch basin in Tract A will also require a catch basin filter to be installed while the outFall system is being constructed for the detention pond. If the BMP options listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D), or if no BMPs are listed above but deemed necessary during construction, the Certified Erosion and Sediment Control Lead shall implement one or more of the alternative BMP inlet protection options listed in Appendix C. 3.1.8 Element#8 — Stabilize Channels and Outlets Where site runoff is to be conveyed in channels, or discharged to a stream or some other natural drainage point, efforts will be taken to prevent downstream erosion. The specific BMPs for channel and outlet stabilization that shall be used on this project include: • No BMPs implemented The project will not discharge to any outlets or channels; therefore no BMP's are required. Alternate channel and outlet stabilization BMPs are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ' ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. The project site is located west of the Cascade Mountain Crest. As such, all temporary on-site conveyance channels shall be designed, constructed, and stabilized to prevent O 2015 D.R.STRONG Consulting Engineers Inc. Page 10 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 Stormwater Pollution Prevention Plan erosion from the expected peak 10 minute velocity of flow from a Type 1A, 10-year, 24- hour recurrence interval storm for the developed condition. Alternatively, the 10-year, 1- hour peak flow rate indicated by an approved continuous runoff simulation model, increased by a factor of 1.6, shall be used. Stabilization, including armoring material, adequate to prevent erosion of outlets, adjacent streambanks, slopes, and downstream , reaches shall be provided at the outlets of all conveyance systems. � 3.1.9 Element#9 — Control Pollutants All pollutants, including waste materials and demolition debris, that occur onsite shall be handled and disposed of in a manner that does not cause contamination of stormwater. , Good housekeeping and preventative measures will be taken to ensure that the site will , be kept clean, well-organized, and free of debris. If required, BMPs to be implemented to control specific sources of pollutants are discussed below. � Vehicles, construction equipment, and/or petroleum product storage/dispensing: • All vehicles, equipment, and petroleum product storage/dispensing areas will be inspected regularly to detect any leaks or spills, and to identify maintenance needs to prevent leaks or spills. • On-site fueling tanks and petroleum product storage containers shall include secondary containment. • Spill prevention measures, such as drip pans, will be used when conducting maintenance and repair of vehicles or equipment. • In order to perform emergency repairs on site, temporary plastic will be placed beneath and, if raining, over the vehicle. • Contaminated surfaces shall be cleaned immediately following any discharge or spill incident. Demolition: • Dust released from demolished sidewalks, buildings, or structures will be controlled using Dust Control measures (BMP C140). • Storm drain inlets vulnerable to stormwater discharge carrying dust, soil, or debris will be protected using Storm Drain Inlet Protection (BMP C220 as described above for Element 7). • Process water and slurry resulting from sawcutting and surfacing operations will be prevented from entering the waters of the State by implementing Sawcutting and Surfacing Pollution Prevention measures (BMP C152). Concrete and grout: • Process water and slurry resulting from concrete work will be prevented from entering the waters of the State by implementing Concrete Handling measures (BMP C151). Sanitary wastewater: O 2015 D. R.STRONG Consulting Engineers Inc_ Page 11 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 Stormwater Pollution Prevention Plan • Portable sanitation facilities will be firmly secured, regularly maintained, and emptied when necessary. Solid Waste: • Solid waste will be stored in secure, clearly marked containers. Other: • Other BMPs will be administered as necessary to address any additional pollutant sources on site. The facility does not require a Spill Prevention, Control, and Countermeasure (SPCC) Plan under the Federal regu�ations of the Clean Water Act (CWA). 3.1.10 Element#10 — Control Dewatering There will be no dewatering as part of this construction project. 3.1.11 Element#11 — Maintain BMPs All temporary and permanent erosion and sediment control BMPs shall be maintained and repaired as needed to assure continued performance of their intended function. Maintenance and repair shall be conducted in accordance with each particular BMPs specifications (attached). Visual monitoring of the BMPs will be conducted at least once every calendar week and within 24 hours of any stormwater or non-stormwater discharge from the site. If the site becomes inactive, and is temporarily stabilized, the inspection frequency will be reduced to once every month. All temporary erosion and sediment control BMPs shall be removed within 30 days after the final site stabilization is achieved or after the temporary BMPs are no longer needed. Trapped sediment shall be removed or stabilized on site. Disturbed soil resulting from removal of BMPs or vegetation shall be permanently stabilized. 3.1.12 Element#12 — Manage the Project Erosion and sediment control BMPs for this project have been designed based on the following principles: • Design the project to fit the existing topography, soils, and drainage patterns. • Emphasize erosion control rather than sediment control. • Minimize the extent and duration of the area exposed. • Keep runoff velocities low. • Retain sediment on site. • Thoroughly monitor site and maintain all ESC measures. • Schedule major earthwork during the dry season. In addition, project management will incorporate the key components listed below: (West Response) As this project site is located west of the Cascade Mountain Crest, the project will be managed according to the following key project components: O 2015 D. R.STRONG Consulting Engineers Inc. Page 12 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 Stormwater Poilution Prevention Plan Phasing of Construction • The construction project is being phased to the extent practicable in order to prevent soil erosion, and, to the maximum extent possible, the transport of sediment from the site during construction. • Revegetation of exposed areas and maintenance of that vegetation shall be an integral part of the clearing activities during each phase of construction, per the Scheduling BMP (C 162). Seasonal Work Limitations • From October 1 through April 30, clearing, grading, and other soil disturbing activities shall only be permitted if shown to the satisfaction of the local permitting authority that silt-laden runoff will be prevented from leaving the site through a combination of the following: o Site conditions including existing vegetative coverage, slope, soil type, and proximity to receiving waters; and o Limitations on activities and the extent of disturbed areas; and o Proposed erosion and sediment control measures. • Based on the information provided and/or local weather conditions, the local permitting authority may expand or restrict the seasonal limitation on site disturbance. • The following activities are exempt from the seasonal clearing and grading limitations: o Routine maintenance and necessary repair of erosion and sediment control BMPs; o Routine maintenance of public facilities or existing utility structures that do not expose the soil or result in the removal of the vegetative cover to soil; and o Activities where there is 100 percent infiltration of surFace water runoff within the site in approved and installed erosion and sediment control facilities. Coordination with Utilities and Other Jurisdictions • Care has been taken to coordinate with utilities, other construction projects, and the local jurisdiction in preparing this SWPPP and scheduling the construction work. Inspection and Monitoring • All BMPs shall be inspected, maintained, and repaired as needed to assure continued performance of their intended function. Site inspections shall be conducted by a person who is knowledgeable in the principles and practices of erosion and sediment control. This person has the necessary skills to: O 2015 D. R.STRONG Consulting Engineers Inc. Page 13 of 44 Storm�vater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 Stormwater Pollution Prevention Plan o Assess the site conditions and construction activities that could impact the quality of stormwater, and o Assess the effectiveness of erosion and sediment control measures used to control the quality of stormwater discharges. • A Certified Erosion and Sediment Control Lead shall be on-site or on-call at all times. • Whenever inspection and/or monitoring reveals that the BMPs identified in this SWPPP are inadequate, due to the actual discharge of or potential to discharge a significant amount of any pollutant, appropriate BMPs or design changes shall be implemented as soon as possible. Maintaining an Updated Construction SWPPP • This SWPPP shall be retained on-site or within reasonable access to the site. • The SWPPP shall be modified whenever there is a change in the design, construction, operation, or maintenance at the construction site that has, or could have, a significant effect on the discharge of pollutants to waters of the state. • The SWPPP shall be modified if, during inspections or investigations conducted by the owner/operator, or the applicable local or state regulatory authority, it is determined that the SWPPP is ineffective in eliminating or significantly minimizing pollutants in stormwater discharges from the site. The SWPPP shall be modified as necessary to include additional or modified BMPs designed to correct problems identified. Revisions to the SWPPP shall be completed within seven (7) days following the inspection. If the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. 3.2 Site Specific BMPs Site specific BMPs are shown on the TESC Plan Sheets and Details in Appendix A. These site specific plan sheets will be updated annually. 3.3 Additional Advanced BMPs O 2015 D. R.STRONG Consuking Engineers Inc. Page 14 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 Stormwater Pollution Prevention Plan 4.0 CONSTRUCTION PHASING AND BMP IMPLEMENTATION The BMP implementation schedule will be driven by the construction schedule. The following provides a sequential list of the proposed construction schedule milestones and the corresponding BMP implementation schedule. The list contains key milestones such as wet season construction. The BMP implementation schedule listed below is keyed to proposed phases of the construction project, and reflects differences in BMP installations and inspections that relate to wet season construction. The project site is located west of the Cascade Mountain Crest. As such, the dry season is considered to be from May 1 to September 30 and the wet season is considered to be from October 1 to April 30. • Estimate of Construction start date: 9/1/2015 • Estimate of Construction finish date: 2/27/2016 • Mobilize equipment on site: 8/25/2015 • Mobilize and store all ESC and soil stabilization products: 8/27/2015 • Install ESC measures: 9/3/2015 • Install stabilized construction entrance: 9/2/2015 • Begin clearing and grubbing: 9/5/2015 • Demolish existing buildings: 8/27/2015 • Begin Site Grading: 9/29/2015 • Begin implementing soil stabilization and sediment control BMPs throughout the site: 9/4/2015 • End Site Grading: 10/30/2015 • Begin Utility Construction: 11/3/2015 • End Utility Construction: 1/12/2016 • Begin Paving and Sidewalk Installation: 1/19/2016 • Permanent erosion control measures (hydroseeding): 10/31/2015 • End Paving and Sidewalk Installation: 2/9/2016 • Final landscaping and planting begins: 2/23/2016 O 2015 D. R.STRONG Consulting Engineers Inc. Page 15 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 Stormwater Pollution Prevention Plan 5.0 POLLUTION PREVENTION TEAM 5.1 Roles and Responsibilities The pollution prevention team consists of personnel responsible for implementation of the SWPPP, including the following: • Certified Erosion and Sediment Control Lead (CESCL) — primary contractor contact, responsible for site inspections (BMPs, visual monitoring, sampling, etc.); to be called upon in case of failure of any ESC measures. • Resident Engineer — For projects with engineered structures only ' (sediment ponds/traps, sand filters, etc.): site representative for the owner that is the project's supervising engineer responsible for inspections and issuing instructions and drawings to the contractor's site supervisor or representative • Emergency Ecology Contact — individual to be contacted at Ecology in case of emergency • Emergency Owner Contact — individual that is the site owner or representative of the site owner to be contacted in the case of an emergency. • Non-Emergency Ecology Contact — individual that is the site owner or representative of the site owner than can be contacted if required. • Monitoring Personnel — personnel responsible for conducting water quality monitoring; for most sites this person is also the Certified Erosion and Sediment Control Lead. 5.2 Team Members Names and contact information for those identified as members of the pollution prevention team are provided in the following table. Title Name(s} Phone Number Certified Erosion and Sediment Control Justin Lagers 253.405.5587 Lead(CESCL) Resident Engineer MaherA.Joudi 425.827.3063 Emergency Ecology Contact NW Regional Office 425.649.7000 Emergency Owner Contact Justin Lagers 253.405.5587 Non-Emergency Ecology Contact Ken Waldo 425.649.7279 Monitoring Personnel TBD �2015 D. R. STRONG Consulting Engineers Inc. Page 16 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 Stormwater Pollution Prevention Plan 6.0 SITE INSPECTIONS AND MONITORING Monitoring includes visual inspection, monitoring for water quality parameters of concern, and documentation of the inspection and monitoring findings in a site log book. A site log book will be maintained for all on-site construction activities and will include: • A record of the implementation of the SWPPP and other permit requirements; • Site inspections; and, • Stormwater quality monitoring. For convenience, the inspection form and water quality monitoring forms included in this SWPPP include the required information for the site log book. This SWPPP may function as the site log book if desired, or the forms may be separated and included in a separate site log book. However, if separated, the site log book but must be maintained on-site or within reasonable access to the site and be made available upon request to Ecology or the local jurisdiction. 6.1 Site Inspection All BMPs will be inspected, maintained, and repaired as needed to assure continued perFormance of their intended function. The inspector will be a Certified Erosion and Sediment Control Lead (CESCL) per BMP C160. The name and contact information for the CESCL is provided in Section 5 of this SWPPP. Site inspection will occur in all areas disturbed by construction activities and at all stormwater discharge points. Stormwater will be examined for the presence of suspended sediment, turbidity, discoloration, and oily sheen. The site inspector will evaluate and document the effectiveness of the installed BMPs and determine if it is necessary to repair or replace any of the BMPs to improve the quality of stormwater discharges. All maintenance and repairs will be documented in the site log book or forms provided in this document. All new BMPs or design changes will be documented in the SWPPP as soon as possible. 6.1.1 Site Inspection Frequency Site inspections will be conducted at least once a week and within 24 hours following any discharge from the site. For sites with temporary stabilization measures, the site inspection frequency can be reduced to once every month. 6.1.2 Site Inspection Documentation The site inspector will record each site inspection using the site log inspection forms provided in Appendix E. The site inspection log forms may be separated from this SWPPP document, but will be maintained on-site or within reasonable access to the site and be made available upon request to Ecology or the local jurisdiction. :.�2015 D. R. STRONG Consulting Englneers Inc. Page 17 of 44 Storm�vater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 L Stormwater Pollution Prevention Plan 6.2 Stormwater Quality Monitoring The Site will discharge into an existing storm drainage system. Before project discharge leaves the Site, it enters a combined detention/wet pond before entering the existing conveyance system located within 156th Avenue SE. This will be sufficient in accommodating water quality requirements. Testing at the outlet will still occur as necessary. 6.2.1 Turbidity Sampling Sampling and monitoring will be conducted during the entire construction phase of the project. Samples will be collected daily at the downstream catch basin for both the pond and vault. If there is no flow in this catch basin, the attempt to sample will be recorded in the site log book and reported to Ecology in the monthly Discharge Monitoring Report (DMR) as "No Discharge". Samples will be analyzed for turbidity using the EPA 180.1 analytical method. The key benchmark turbidity value is 25 nephelometric turbidity units (NTU) for the downstream receiving water body. If the 25 NTU benchmark is exceeded in any sample collected from the tested catch basins, the following steps will be conducted: 1. Ensure all BMPs specified in this SWPPP are installed and functioning as intended. 2. Assess whether additional BMPs should be imp�emented, and document modified BMPs in the SWPPP as necessary. 3. Sample discharge daily until the discharge is 25 NTU or lower. If the turbidity exceeds 250 NTU at any time, the following steps will be conducted: 1. Notify Ecology by phone within 24 hours of analysis (see Section 5.0 of this SWPPP for contact information). 2. Continue sampling daily until the discharge is 25 NTU or lower Initiate additional treatment BMPs such as off-site treatment, infiltration, filtration and chemical treatment within 24 hours, and implement those additional treatment BMPs as soon as possible, but within a minimum of 7 days. 3. Describe inspection results and remedial actions taken in the site log book and in monthly discharge monitoring reports as described in Section 7.0 of this SWPPP. 6.2.2 pH Sampling Sampling and monitoring for pH will occur during the phase of construction when concrete pouring will be conducted until fully cured (3 weeks from last pour) and discharges are documented to be below pH 8.5. Samples will be collected weekly at the sedimentation pond prior to discharge to surface water. Samples will be analyzed for pH using a calibrated pH meter and recorded in the site log book. The key benchmark pH value for stormwater is a maximum of 8.5. If a pH greater than 8.5 is measured in the sedimentation trap/pond(s) that has the potential to discharge to surface water, the following steps will be conducted: O 2015 D. R.STRONG Consulting Engineers Inc. Page 18 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 Stormwater Pollution Prevention Plan 1. Prevent (detain) all discharges from leaving the site and entering surFace waters or storm drains if the pH is greater than 8.5 2. Implement CO2 sparging or dry ice treatment in accordance with Ecology BMP C252. Describe inspection results and remedial actions that are taken in the site log book and in monthly discharge monitoring reports as described in Section 7.0 of this SWPPP. 6.2.3 Temperature Monitoring No temperature monitoring is required for this construction site. O 2015 D.R.STRONG ConsuRing Engineers Inc. Page 19 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 Stormwater Pollution Prevention Plan 7.0 REPORTING AND RECORDKEEPING 7.1 Recordkeeping 7.1.1 Site Log Book A site log book will be maintained for all on-site construction activities and will include: • A record of the implementation of the SWPPP and other permit requirements; • Site inspections; and, • Stormwater quality monitoring. For convenience, the inspection form and water quality monitoring forms included in this SWPPP include the required information for the site log book. 7.1.2 Records Retention Records of all monitoring information (site log book, inspection reports/checklists, etc.), this Stormwater Pollution Prevention Plan, and any other documentation of compliance with permit requirements will be retained during the life of the construction project and for a minimum of three years following the termination of permit coverage in accordance with permit condition S5.C. 7.1.3 Access to Plans and Records The SWPPP, General Permit, Notice of Authorization letter, and Site Log Book will be retained on site or within reasonable access to the site and will be made immediately available upon request to Ecology or the local jurisdiction. A copy of this SWPPP will be provided to Ecology within 14 days of receipt of a written request for the SWPPP from Ecology. Any other information requested by Ecology will be submitted within a reasonable time. A copy of the SWPPP or access to the SWPPP will be provided to the public when requested in writing in accordance with permit condition SS.G. 7.1.4 Updating the SWPPP In accordance with Conditions S3, S4.B, and S9.B.3 of the General Permit, this SWPPP will be modified if the SWPPP is ineffective in eliminating or significantly minimizing pollutants in stormwater discharges from the site or there has been a change in design, construction, operation, or maintenance at the site that has a significant effect on the discharge, or potential for discharge, of pollutants to the waters of the State. The SWPPP will be modified within seven days of determination based on inspection(s) that additional or modified BMPs are necessary to correct problems identified, and an updated timeline for BMP implementation will be prepared. O 2015 D. R.STRONG Consulting Engineers Inc. Page 20 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 1 , Stormwater Pollution Prevention Plan 7.2 Reporting 7.2.1 Discharge Monitoring Reports Water quality sampling results will be submitted to Ecology monthly on Discharge Monitoring Report (DMR) forms in accordance with permit condition S5.B. If there was no discharge during a given monitoring period, the form will be submitted with the words "no discharge" entered in place of the monitoring results. If a benchmark was exceeded, a brief summary of inspection results and remedial actions taken will be included. If sampling could not be perFormed during a monitoring period, a DMR will be submitted with an explanation of why sampling could not be performed. 7.2.2 Notification of Noncompliance If any of the terms and conditions of the permit are not met, and it causes a threat to human health or the environment, the following steps will be taken in accordance with permit section SS.F: 1. Ecology will be immediately notified of the failure to comply. 2. Immediate action will be taken to control the noncompliance issue and to correct the problem. If applicable, sampling and analysis of any noncompliance will be repeated immediately and the results submitted to Ecology within five (5) days of becoming aware of the violation. 3. A detailed written report describing the noncompliance will be submitted to Ecology within five (5) days, unless requested earlier by Ecology. Any time turbidity sampling indicates turbidity is 250 nephelometric turbidity units (NTU) or greater or water transparency is 6 centimeters or less, the Ecology regional office will be notified by phone within 24 hours of analysis as required by permit condition S5.A (see Section 5.0 of this SWPPP for contact information). In accordance with permit condition S4.F.6.b, the Ecology regional office will be notified if chemical treatment other than CO2 sparging is planned for adjustment of high pH water (see Section 5.0 of this SWPPP for contact information). 7.2.3 Permit Application and Changes In accordance with permit condition S2.A, a complete application form will be submitted to Ecology and the appropriate local jurisdiction (if applicable} to be covered by the General Permit. O 2015 D.R.STRONG Consulting Engineers Inc. Page 21 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 Stormwater Pollution Prevention Plan APPENDIX A - SITE PLANS �2015 D. R. STRONG Consulting Engineers Inc. Page 22 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23, 2014 N � THE4El�lC_ 14�VEAHT BR%DLE R%DGE ,� , ,- o � ' ��,�',��G�t�ss sL�� O � � ' � � CONSTRUC IION SEQUENCE.• O � - - �I �� -_ i.vaE-carsraucnaa utFrwG I �'T. 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BY: Date: � 4;.I?CH 2]Od TREE PROTEC770N DETAIL DRw�JNE BY: Date � �oC' N _ �a "�'�� an oo�rg>>��.�4 �w ��s �w s,s �� C I Y OF THE ENCLAVE AT BRIDLE RIDGE �'��o.oa.�4 i 0.2 STRONG t an cwons �w os.�a.is ra � �,�5 NpTEp •'"�"'"'�°'�'.�" �_ ; Cd 2 Warknp Dap Bslas Yw Oip 'i�' . � CONSULTING ENG'INEERS � :�-�I T O N � 8� � ��, � ��s�� °"""nP � �� TESC NOTES AND DETAILS e �pyb��yb�opq�p�4 p� �� D ��.�� Flcnnirg/Buildirg/Public 'Nor4s Dept. � C� F.' � (DAIT.PD.OF�WA) �ti,1L � eevsni�rs+.E/a�na.v�o.�+s�aeau �,�. ��iI50N 6Y CATE A=FR 4••c•�"• y o.aena�Fasm,�w �w U14005368 � � DRS PROJECT N0. 13117 A -N N N A APPENDIX B - CONSTRUCTION BMPS High Visibility Plastic or Metal Fence (BMP C103) Stabilized Construction Entrance (BMP C105) Construction Road/Parking Area Stabilization (BMP C107) Temporary and Permanent Seeding (BMP C120) Plastic Covering (BMP C123) Dust Control (BMP C140) Materials on Hand (BMP C150) Interceptor Swale (BMP C200) Check Dams (BMP C207) Storm Drain Inlet Protection (BMP C220) Silt Fence (BMP C233) Detention Pond � �2015 D. R.STRONG Consulting Engineers Inc. Page 23 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 � � Stormwater Pollution Prevention Plan APPENDIX C - ALTERNATIVE BMPS The following includes a list of possible alternative BMPs for each of the 12 elements not described in the main SWPPP text. This list can be referenced in the event a BMP for a specific element is not functioning as designed and an alternative BMP needs to be implemented. None Proposed ;�2015 D. R.STRONG Consulting Engineers Inc. Page 24 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 1 APPENDIX D - GENERAL PERMIT O 2015 D. R.STRONG Consulting Engineers Inc. Page 25 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 � � � Issuance Date: December 1, 2010 � Effective Date: January l, 2011 Expiration Date: December 31, 20I5 ��l`��J ��1� �� GEI�TE P� I'T National Pollutant Discharge Elimination System (NPDES) and State Waste Discharge General � Permit for Stormwater Discharges Associated with Construction Activity , S#ate of Washington Department of Ecology Olympia, Washington 98504 In compliance with the provisions of . Chapter 90.48 Revised Code of Washinb on -� . (State of Washington Water Pollution Control Act) - and Title 33 United States Code, Section 1251 et seq. � The Federai Water Pollution Control Act(The Clean Water Act} " - Until this pernut expires, is modified or revoked, Permittees that have properly obtained coverage under this general permit are authorized to discharge in accordance with the special and general conditions that follow. �e Susewind, P.E., P.G. ater Quality Program Manager VJashington State Department of Ecology TABLE OF CONTENTS � LISTOF TABLES.......................................................................................................................... 3 SPECIALCONDITIONS............................................................................................................... 5 S1. PERMIT COVERAGE........................................................................................................5 S2. APPLICATION REQUIREMENTS ...................................................................................8 S3. COMPLIANCE WITH STANDARDS.............................................................................11 S4. MONITORING REQUIREMENTS..................................................................................12 S5. REPORTING AND RECORDKEEPING REQUIREMENTS .........................................19 S6. PERMIT FEES...................................................................................................................22 S7. SOLID AND LIQUID WASTE DISPOSAL ....................................................................22 S8. DISCHARGES TO 303(D) OR TMDL WATER BODIES..............................................22 S9. STORMWATER POLLUTION PREVENTION PLAN...................................................26 S10. NOTICE OF TERMINATION..........................................................................................34 GENERALCONDITIONS ..........................................................................................................36 Gl. DISCHARGE VIOLATIONS ...........................................................................................36 G2. SIGNATORY REQUIREMENTS.....................................................................................36 G3. RIGHT OF INSPECTION AND ENTRY.........................................................................37 G4. GENERAL PERMIT MODIFICATION AND REVOCATION......................................37 G5. REVOCATION OF COVERAGE UNDER THE PERMIT .............................................37 G6. REPORTING A CAUSE FOR MODIFICATION............................................................3 8 G7. COMPLIANCE WITH OTHER LAWS AND STATUTES.............................................38 G8. DUTY TO REAPPLY .......................................................................................................3 8 � G9. TRANSFER OF GENERAL PERMIT COVERAGE.......................................................39 G10. REMOVED SUBSTANCES.............................................................................................39 G11. DUTY TO PROVIDE INFORMATION...........................................................................39 G12. OTHER REQUIREMENTS OF 40 CFR...........................................................................39 G13. ADDITIONAL MONITORING........................................................................................39 G14. PENALTIES FOR VIOLATING PERMIT CONDITIONS .............................................40 G15. UPSET ...............................................................................................................................40 Construction Stormwatet� Genef-al Permit—December 1, 2010 Page 2 G16. PROPERTY RIGHTS........................................................................................................40 G17. DUTY TO COMPLY ........................................................................................................40 G18. TOXIC POLLUTANTS.....................................................................................................41 G19. PENALTIES FOR TAMPERING.....................................................................................41 G20. REPORTING PLANNED CHANGES .............................................................................41 G21. REPORTING OTHER INFORMATION..........................................................................42 G22. REPORTING ANTICIPAT�D NON-COMPLIANCE.....................................................42 G23. REQUESTS TO BE EXCLUDED FROM COVERAGE UNDER THE PERMIT..........42 G24. APPEALS ..........................................................................................................................42 G25. SEVERABILITY...............................................................................................................43 G26. BYPASS PROHIBITED....................................................................................................43 APPENDIXA—DEFINITIONS..................................................................................................46 APPENDIXB —ACRONYMS .................................................................................................... 54 LIST OF TABLES Table 1. Summary of Permit Report Submittals.......................................................................4 Table 2. Summary of Required On-site Documentation...........................................................4 Table 3. Summary of Primary Monitoring Requirements ...................................................... 12 Table 4. Monitoring and Reporting Requirements ................................................................. 16 Table 5. Turbidity, Fine Sediment& Phosphorus Sampling and Limits for 303(d)-Listed... 24 Table 6. pH Sampling and Limits for 303(d)-Listed Waters..................................................24 Construction Stormlvatef-Genef�al Perfnit—Decerrlbef• 1, 2010 Page 3 SUMMARY OF PERMIT REPORT SUBMITTALS Refer to the Special and General Conditions within this permit for additional submittal requirements. Appendix A provides a list of definitions. Appendix B provides a list of acronyms. Table 1. Summary of Permit Report Submittals Permit Submittal Frequency First Submittal Date Section SS.A and High Turbidity/Transparency Phone As Necessary Within 24 hours S8 Reporting SS.B Discharge Monitoring Report Monthly* Within 15 days of applicable monitoring eriod SS.F and Noncompliance Notification As necessary Immediately S8 SS.F Noncompliance Notification — As necessary Within 5 Days of non- Written Report compliance G2. Notice of Change in Authorization As necessary G6. Permit Application for Substantive As necessary Changes to the Discharge G8. Application for Permit Renewal 1/permit cycle No later than 180 days before expiration G9. Notice of Permit Transfer As necessary G20. Notice of Planned Changes As necessary G22. Reporting Anticipated Non- As necessary compliance SPECIAL NOTE: *Permittees must submit Discharge Monitoring Reports(DMRs)to the Washington State Department of Ecology monthly,regardless of site discharge, far the full duration of permit coverage. Refer to Section SS.B of this General Permit for mare specific information regarding DMRs. Table 2. Summary of Required On-site Documentation Document Title Permit Conditions Permit Coverage Letter See Conditions S2, S5 Construction Stormwater General Permit See Conditions S2, S5 Site Log Book See Conditions S4, S5 Stormwater Pollution Prevention Plan (SWPPP) See Conditions S9, S5 Construction Stormwater Genef�al Per•mit—December� 1, 2010 Page 4 SPECIAL CONDITIONS S1. PERMIT COVERAGE A. Permit Area This Construction Stormwater General Permit(CSWGP) covers all areas of Washington State, except for federal and Tribal lands as specified in Special Condition S1.E.3. B. Operators Required to Seek Coverage Under this General Permit: 1. Operators of the following construction activities are required to seek coverage under this CSWGP: a. Clearing, grading and/or excavation that results in the disturbance of one or more acres and discharges stormwater to surface waters of the State; and clearing, grading and/or excavation on sites smaller than one acre that are part of a larger common plan of development or sale, if the common plan of development or sale will ultimately disturb one acre or more and discharge stormwater to surface waters of the State. i. This includes forest practices (including, but not limited to, class IV conversions) that are part of a construction activity that will result in the disturbance of one or more acres, and discharge to surface waters of the State(that is, forest practices that prepare a site for construction activities); and b. Any size construction activity discharging stormwater to waters of the State that the Department of Ecology ("Ecology"): i. Determines to be a significant contributor of pollutants to waters of the State of Washington. ii. Reasonably expects to cause a violation of any water quality standard. 2. Operators of the following activities are not required to seek coverage under this CSWGP (unless specifically required under Special Condition S1.B.l.b. above): a. Construction activities that discharge all stormwater and non-stormwater to ground water, sanitary sewer, or combined sewer, and have no point source discharge to either surface water or a storm sewer system that drains to surface waters of the State. b. Construction activities covered under an Erosivity Waiver(Special Condition S2.C). c. Routine maintenance that is performed to maintain the original line and grade, hydraulic capacity, or original purpose of a facility. Construction Stormwater General Permit—December 1, 2010 Page 5 C. Authorized Dischara,es: 1. Stormwater Associated with Construction Activitv. Subject to compliance with the terms and conditions of this permit, Permittees are authorized to discharge stormwater associated with construction activity to surface waters of the State or to a storm sewer system that drains to surface waters of the State. (Note that"surface waters of the State" may exist on a construction site as well as off site; for example, a creek running through a site.) 2. Stormwater Associated with Construction Support Activitv. This permit also authorizes stormwater discharge from support activities related to the permitted construction site (for example, an on-site portable rock crusher, off-site equipment staging yards, material storage areas, borrow areas, etc.) provided: a. The support activity relates directly to the permitted construction site that is required to have a NPDES permit; and b. The support activity is not a commercial operation serving multiple unrelated construction projects, and does not operate beyond the completion of the construction activity; and c. Appropriate controls and measures are identified in the Stormwater Pollution Prevention Plan(SWPPP) for the discharges from the support activity areas. 3. Non-Stormwater Discharges. The categories and sources of non-stormwater discharges identified belo�v are authorized conditionally,provided the discharge is consistent with the terms and conditions of this permit: a. Discharges from fire-fighting activities. b. Fire hydrant system flushing. c. Potable water, including uncontaminated water line flushing. d. Pipeline hydrostatic test water. e. Uncontaminated air conditioning or compressor condensate. f. Uncontaminated ground water ar spring��vater. g. Uncontaminated excavation dewatering water(in accordance with S9.D.10). I h. Uncontaminated discharges from foundation or footing drains. i. Water used to control dust. Permittees must minimize the amount of dust control water used. j. Routine external building «�ash down that does not use detergents. k. Landscape irrigation water. The SWPPP must adequately address all authorized non-storm��vater discharges, except far discharges from fire-fighting activities, and must compl��-�ith Special ' Consty-uction Stof•mwater Gener�al Permit—Decen�zbef• 1, 2010 Page 6 Condition S3. At a minimum, discharges from potable water (including water line flushing), fire hydrant system flushing, and pipeline hydrostatic test water must undergo the following: dechlorination to a concentration of 0.1 parts per million , (ppm)or less, and pH adjustment to �vithin 6.5 — 8.5 standard units (su), if ' necessary. D. Prohibited Discharges: The following discharges to waters of the State, including ground �vater, are prohibited. 1. Concrete wastewater. 2. Wastewater from washout and clean-up of stucco, paint, fomi release oils, curing compounds and other construction materials. 3. Process wastewater as defined by 40 Code of Fedei•al Regulations (CFR) 122.1 (see Appendix A of this permit). 4. Slurry materials and waste from shaft drilling. 5. Fuels, oils, or other pollutants used in vehicle and equipment operation and maintenance. 6. Soaps or solvents used in vehicle and equipment ��ashing. 7. Wheel wash��astewater, unless discharged accarding to Special Condition S9.D.9.d. 8. Discharges from dewatering activities, including discharges from dewatering of trenches and excavations, unless managed according to Special Condition S9.D.10. E. Limits on Coveraee Ecology may require any discharger to apply for and obtain coverage under an individual permit or another more specific general permit. Such alternative coverage will be required when Ecology determines that this CSWGP does not provide adequate assurance that water quality will be protected, or there is a reasonable potential for the project to cause or contribute to a violation of water quality standards. The following stormwater discharges are not covered by this permit: 1. Post-construction storm��ater discharges that originate from the site after completion of construction activities and the site has undergone final stabilization. 2. Non-point source silvicultural activities such as nursery operations, site preparation, reforestation and subsequent cultural treatment,thinning,prescribed burning,pest and fire control, harvesting operations, surface drainage, or road construction and maintenance, from�vhich there is natural runoff as excluded in 40 CFR Subpart 122. 3. Stormwater from any feder•al project or project on federal land or land within an Indian Reservation e�cept for the Puyallup Reservation. `'Vithin the Puyallup Construction Stormwater Genercal Perrs�iit—Decenaber� 1, 2010 Page 7 Reservation, any project that discharges to surface water on land held in trust by the federal government may be covered by this permit. 4. Stormwater from any site covered under an existing NPDES individual permit in which stormwater management and/or treatment requirements are included for all stormwater discharges associated with construction activity. 5. Stormwater from a site where an applicable Total Maximum Daily Load (TMDL) requirement specifically precludes or prohibits discharges from construction activity. S2. APPLICATION REQUIREMENTS A. Permit Application Forms 1. Notice of Intent Form/Timeline a. Operators of new or previously unpermitted construction activities must submit a complete and accurate permit application (Notice of Intent, or NOI) to Ecology. b. The operator must submit the NOI at least 60 days before discharging stormwater from construction activities and must submit it on or before the date of the first public notice (see Special Condition S2.B below for details). The 30-day public comment period required by WAC 173-226-130(5) begins on the publication date of the second public notice. Unless Ecology responds to the complete application in writing, based on public comments, or any other relevant factors, coverage under the general permit will automatically commence on the thirty-first day following receipt by Ecology of a completed NOI, or the issuance date of this permit, whichever is later, unless Ecology specifies a later date in writing. c. Applicants who propose to discharge to a storm or sewer system operated by Seattle, King County, Snohomish County, Tacoma, Pierce County, or Clark County must also submit a copy of the NOI to the appropriate jurisdiction. d. If an applicant intends to use a Best Management Practice(BMP) selected on the basis of Special Condition S9.C.4 ("demonstrably equivalent" BMPs), the applicant must notify Ecology of its selection as part of the NOI. In the event the applicant selects BMPs after submission of the NOI, it must provide notice of the selection of an equivalent BMP to Ecology at least 60 days before intended use of the equivalent BMP. e. Pernuttees must notify Ecology regarding any changes to the information provided on the NOI by submitting an updated NOI. Examples of such changes include, but are not limited to, i. changes to the Permittee's mailing address, ii. changes to the on-site contact person information, and Construction Stormia�ater General Per•rrlit—December• 1, 2010 Page 8 iii. changes to the area/acreage affected by construction activity. 2. Transfer of Covera eg Form The Permittee can transfer current coverage under this permit to one or more new operators, including operators of sites within a Common Plan of Development, provided the Permittee submits a Transfer of Coverage Form in accordance with General Condition G9. Transfers do not require public notice. B. Public l�Totice For new or previously unpermitted construction activities, the applicant must publish a public notice at least one time each week for two consecutive weeks, at least 7 days apart, in a newspaper with general circulation in the county where the construction is to take place. The notice must contain: 1. A statement that"The applicant is seeking coverage under the Washington State Department of Ecology's Construction Stormwater NPDES and State Waste Discharge General Permit." 2. The name, address and location of the construction site. 3. The name and address of the applicant. 4. The type of construction activity that will result in a discharge (for example, residential construction, commercial construction, etc.), and the number of acres to be disturbed. 5. The name of the receiving water(s) (that is,the surface water(s) to which the site will discharge), or, if the discharge is through a storm sewer system,the namc of the operator of the system. 6. The statement: "Any persons desiring to present their views to the Washington State Department of Ecology regarding this application, or interested in Ecology's action on this application,may notify Ecology in wi-iting no later than 30 days of the last date of publication of this notice. Ecology reviews public comments and considers whether discharges from this project would cause a measurable change in receiving water quality, and, if so, whether the project is necessary and in the overriding public interest according to Tier II antidegradation requirements under WAC 173-201A-320. Comments can be submitted to: Department of Ecology, P.O. Box 47696,Olympia, ��VA 98504-7696 Attn: Water Quality Program, Construction Storm��ater." Construction Stornativater General Permit—December 1, 2010 Page 9 ,�3-,� . C. Erosivity Waiver Construction site operators may qualify for an erosivity waiver from the CSWGP if the following conditions are met: 1. The site will result in the disturbance of fewer than 5 acres and the site is not a portion of a common plan of development or sale that�vill disturb 5 acres or greater. i, 2. Calculation of Erosivity "R" Factor and Regional Timeframe: a. The project's rainfall erosivity factor{"R" Factor) must be less than 5 during the period of construction activity, as calculated using either the Texas A&M University online rainfall erosivity calculator at: http://ei.tamu.edu/ar EPA's calculator at http://cfnub.epa.gov/nndes/stormwater/lew/lewcalculator.cfin. The period of construction activity starts when the land is first disturbed and ends with final stabilization. In addition: b. The entire period of construction activity must fall «�ithin the following timeframes: i. For sites west of the Cascades Crest: June 15 — September 1�. ii. For sites east of the Cascades Crest, excluding the Central Basin: June 1� — October 15. iii. For sites east of the Cascades Crest, within the Central Basin: no additional timeframe restrictions apply. The Central Basin is defined as the portions of Eastern Washington with mean annual precipitation of less than 12 inches. For a map of the Central Basin(Region 2), refer to http://www.ecv.wa.�ov/pubs/ecv070202.pdf. 3. Construction site operators must submit a complete Erosivity Waiver certification form at least one week before disturbing the land. Certification must include statements that the operator will: a. Comply with applicable local storm��-ater requirements; and b. Implement appropriate erosion and sediment control BMPs to pre�-ent violations of water quality standards. 4. This waiver is not available for facilities declared significant contributors of pollutants as defined in Special Condition S 1.B.l.b. 5. This waiver does not apply to construction activities which include non- stormwater discharges listed in Special Condition S1.C3. 6. If construction activity estends beyond the certified«-aiver pei•iod for any reason, the operator must either: a. Recalculate the rainfall erosivity "R" factor using the original start date and a ne�v projected ending date and, if the "R" factor is still under � and the entire Construction Stormtivater General Pernzit—Decenrbef� 1, 2010 Page 10 project falls within the applicable regional timeframe in Special Condition S2.C.2.b, complete and submit an amended waiver certification form before the original waiver expires; or b. Submit a complete permit application to Ecology in accordance with Special Condition S2.A and B before the end of the certified waiver period. S3. COMPLIANCE WITH STANDARDS A. Discharges must not cause or contribute to a violation of surface water quality standards (Chapter 173-201A WAC), ground water quality standards (Chapter 173-200 WAC), sediment management standards (Chapter 173-204 WAC), and human health- based criteria in the National Toxics Rule (40 CFR Part 131.36). Discharges not in compliance with these standards are not authorized. B. Prior to the discharge of stormwater and non-stormwater to waters of the State, the Permittee must apply all known, available, and reasonable methods of prevention, control, and treatment(AKART). This includes the preparation and implementation of an adequate Stormwater Pollution Prevention Plan (SWPPP), with all appropriate BMPs installed and maintained in accordance with the SWPPP and the terms and conditions of this permit. C. Ecology presumes that a Permittee complies with water quality standards unless discharge monitoring data or other site-specific information demonstrates that a discharge causes or contributes to a violation of water quality standards, when the Permittee complies with the following conditions. The Permittee must fully: 1. Comply with all permit conditions, including planning, sampling, monitoring, reporting, and recordkeeping conditions. 2. Implement stormwater BMPs contained in stormwater management manuals published or approved by Ecology, or BMPs that are demonstrably equivalent to BMPs contained in stormwater technical manuals published or approved by Ecology, including the proper selection, implementation, and maintenance of all applicable and appropriate BMPs for on-site pollution control. (For purposes of this section, the stormwater manuals listed in Appendix 10 of the Phase I Municipal Stormwater Permit are approved by Ecology.) D. Where construction sites also discharge to ground water, the ground water discharges must also meet the terms and conditions of this CSWGP. Permittees w�ho discharge to ground water through an injection well must also comply with any applicable requirements of the Underground Injection Control (UIC) regulations, Chapter 173-218 WAC. Construction Stormwater General Permit—December 1, 2010 Page 11 S4. MONITORING REQUIREMENTS, BENCHMARKS AND REPORTING TRIGGERS Table 3. Summary of Primary Monitoring Requirements Size of Soil Weekly Site Weekly Weekly Weekly pH Requires Disturbance' Inspections Sampling w/ Sampling w! Sampling2 CESCL Turbidity Transparency Certification? Meter Tube Sites that disturb Required Not Required Not Required Not Required No less than 1 acre, but are part of a larger Common Plan of Development Sites that disturb 1 Required Sampling Rec�uired— Required Yes ; acre or more, but either method � fewer than 5 acres ' Sites that disturb 5 Required Required Not Required Required Yes � acres or more ; A. Site Log Book The Permittee must maintain a site log book that contains a record of the implementation of the SWPPP and other permit requirements, including the installation and maintenance of BMPs; site inspections, and stormwater monitoring. B. Site Inspections The Permittee's (operator's) site inspections must include all areas disturbed by construction activities, all BMPs, and all stormwater discharge points. (See Special Conditions S4.B.3 and B.4 below for detailed requirements of the Permittee's Certified Erosion and Sediment Control Lead [CESCL]). ` Soil disturbance is calculated by adding together all areas affected by construction activity. Construction activity means clearing,grading,excavation,and any other activity that disturbs the surface of the land, including ingress/egress from the site. 2 If construction activity results in the disturbance of 1 acre or more,and involves significant concrete work(1,000 cubic yards of poured or recycled concrete over the life of a project)or the use of engineered soils(soil amendments including but not limited to Portland cement-treated base[CTB), cement kiln dust[CKD],or fly ash),and stormwater from the affected area drains to surface waters of the State or to a storm sewer stormwater collection system that drains to other surface waters ofthe State,the Pernuttee must conduct pH monitoring sampling in accordance with Special Condition S4.D. 3 Sites with one or more acres,but fewer than 5 acres of soil disturbance,must conduct turbidity or transparency sampling in accordance with Special Condition S4.C. 4 Sites equal to or greater than 5 acres of soil disturbance must conduct turbidity sampling using a turbidity meter in accordance with Special Condition S4.C. Construction Storrntivater General Perniit—Decernber• 1, 2010 Page 12 I Construction sites one acre or lar er that dischar e stormwater to surface �vaters of the � g State must have site inspections conducted by a certified CESCL. Sites less than one acre may have a person without CESCL certification conduct inspections; sampling is not required on sites that disturb less than an acre. 1. The Permittee must examine stormwater visually for the presence of suspended - sediment,turbidity, discoloration, and oil sheen. The Permittee must evaluate the effectiveness of BMPs and determine if it is necessary to install, maintain, or repair BMPs to improve the quality of stormwater discharges. Based on the results of the inspection, the Permittee must correct the problems identified by: a. Reviewing the SWPPP for compliance with Special Condition S9 and making appropriate revisions within 7 days of the inspection. b. Immediately beginning the process of fully implementing and maintaining appropriate source control and/or treatment BMPs as soon as possible, addressing the problems no later than within 10 days of the inspection. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when an extension is requested by a Permittee within the initial 10-day response period. c. Documenting BMP implementation and maintenance in the site log book. 2. The Permittee must inspect all areas disturbed by construction activities, all BMPs, and all stormwater discharge points at least once every calendar week and within 24 hours of any discharge from the site. (For purposes of this condition, individual discharge events that last more than one day do not require daily inspections. For example, if a stormwater pond discharges continuously over the course of a week, only one inspection is required that week.} The Permittee may reduce the inspection frequency for temporarily stabilized, inactive sites to once every calendar month. 3. The Permittee must have staff kno��ledgeable in the principles and practices of erosion and sediment control. The CESCL (sites one acre or more) or inspector (sites less than one acre) must have the skills to assess the: a. Site conditions and construction activities that could impact the quality of stormwater, and b. Effectiveness of erosion and sediment control measures used to conh�ol the quality of stormwater discharges. 4. The SWPPP must identify the CESCL or inspector, who must be present on site or on-call at all times. The CESCL must obtain this certification through an approved erosion and sediment control training program that meets the minimum training standards established by Ecolog}� (see Bi�1P C 160 in the manual referred to in Special Condition S9.C.1 and 2). Constf�uction Stormwater General Per�rriit--Decenzber• 1, 2010 Page 13 � I __I :� 5. The Permittee must summarize the results of each inspection in an inspection report or checklist and enter the reportJchecklist into, or attach it to, the site log book.At a minimum, each inspection report or checklist must include: a. Inspection date and time. b. Weather information,the general conditions during inspection and the approximate amount of precipitation since the last inspection, and precipitation within the last 24 hours. c. A summary or list of all implemented BMPs, including observations of all erosion/sediment control structures or practices. d. A description of the locations: i. Of BMPs inspected. ii. Of BMPs that need maintenance and��-hy. iii. Of BMPs that failed to operate as designed or intended, and iv. Where additional or different BMPs are needed, and why. e. A description of stormwater discharged from the site. The Permittee must note the presence of suspended sediment, turbidity, discoloration, and oil sheen, as applicable. f. Any water quality monitoring performed during inspection. g. General comments and notes, including a brief description of any BMP repairs, maintenance or installations made following the inspection. h. A summary report and a schedule of implementation of the remedial actions that the Permittee plans to take if the site inspection indicates that the site is out of compliance. The remedial actions taken must meet the requiremcnts of the SWPPP and the pennit. i. The name,title, and signature of the person conducting the site inspection, a phone number or other reliable method to reach this person, and the following statement: "I certify that this report is true, accurate, and complete to the best of my knowledge and belief." C. Turbiditv/Transparencv SamplinQ Requirements 1. Sampling Methods a. If construction activity involves the disturbance of 5 acres or more, the Permittee must conduct turbidity sampling per Special Condition S4.C. b. If construction activity involves 1 acre or more but fewer than 5 acres ol�soil disturbance, the Permittee must conduct either transparency samplina or turbidity sampling per Special Condition S4.C. � Construction Stormwater General Permit—Decembef� 1, 2010 Page 14 2. Sampling Frequency a. The Pernuttee must sample all discharge locations at least once every calendar week when stormwater (or authorized non-stormwater) discharges from the site or enters any on-site surface waters of the state (for example, a creek running through a site). b. Samples must be representative of the flow and characteristics of the discharge. c. Sampling is not required when there is no discharge during a calendar week. d. Sampling is not required outside of normal working hours or during unsafe conditions. e. If the Permittee is unable to sample during a monitoring period, the Permittee must include a brief explanation in the monthly Discharge Monitoring Report (DMR). f. Sampling is not required before construction activity begins. 3. Sampling Locations a. Sampling is required at all points where storm��Tater associated with construction activity (or authorized non-stormwater) is discharged off site, including where it enters any on-site surface ��aters of the state (for example, a creek running through a site). b. The Permittee may discontinue sampling at discharge points that drain areas of the project that are fully stabilized to prevent erosion. c. The Permittee must identify all sampling point(s) on the SWPPP site map and clearly mark these points in the field ��ith a flag; tape, stake or other`�isible marker. d. Sampling is not required for discharge that is sent directly to sanitary or combined sewer systems. 4. Sampling and Analysis Methods a. The Permittee performs turbidit�r analysis ��ith a calibrated turbidity meter (turbidimeter) either on site or at an accredited lab. The Permittee must record the results in the site log book in nephelometric turbidity units (NTU). b. The Pernuttee performs transparency analysis on site with a 13/4-inch- diameter, 60-centimeter(cm)-long transparency tube. The Permittee will record the results in the site log book in centimeters (cm). Transparency tubes are available from: http://«�ateimonitorin�quip.com/pa�es/stream.html. Construction Stormwatef•General Perrnit—December 1, 2010 Page 15 Table 4. Monitoring and Reporting Requirements Parameter Unit Analytical Method Sampling Benchmark Phone Frequency Value Reporting Trigger Value Turbidity NTU SM2130 or EPA Weekly, if 25 NTU 250 NTU 180.1 discharging Transparency cm Manufacturer Weekly, if 33 cm 6 cm instructions, or discharging Ecology guidance 5. Turbidity/Transparency Benchmark Values and Reporting Triggers The benchmark value for turbidity is 25 NTU or less. The benchmark value for transparency is 33 centimeters (cm). Note: Benchmark values do not apply to discharges to segments of water bodies on Washington State's 303(d) list (Category 5) for turbidity, fine sediment, or phosphorus; these discharges are subject to a numeric effluent limit for turbidity. Refer to Special Condition S8 for more information. a. Turbiditv 26—249 NTU, or Transparency 32— 7 cm: If the discharge turbidity is 26 to 249 NTU; or if discharge transparency is less than 33 cm, but equal to or greater than 6 cm, the Permittee must: i. Review the SWPPP for compliance with Special Condition S9 and make appropriate revisions within 7 days of the date the discharge exceeded the benchmark. ii. Immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible, addressing the problems within 10 days of the date the discharge exceeded the benchmark. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time �vhen the Permittee requests an extension within the initial 10-day response period. iii. Document BMP implementation and maintenance in the site log book. b. Turbiditv 250 NTU or greater, or Transparencv 6 cm or less: If a discharge point's turbidity is 250 NTU or greater, or if discharge transparency is less than or equal to 6 cm, the Permittee must complete the reporting and adaptive management process described belo��. i. Telephone the applicable Ecology Region's Environmental Report Tracking System (ERTS) number within 24 hours, in accordance «-ith Special Condition SS.F. • Central Re�ion (Okanogan, Chelan, Douglas, Kittitas, Yakima, Klickitat, Benton): (509) 575-2490 Construction Stormwater General Permit—December 1, 2010 Page 16 • Eastern Region(Adams, Asotin, Columbia, Ferry, Franklin, Garfield, Grant, Lincoln, Pend Oreille, Spokane, Stevens, Walla Walla, Whitman): (509) 329-3400 • Northwest Region(Kitsap, Snohomish, Island, King, San Juan, Skagit, Whatcom): (425) 649-7000 • Southwest Re�ion (Grays Harbor, Lewis, Mason, Thurston, Pierce, Clark, Cowlitz, Skamania, Wahkiakum, Clallam, Jefferson, Pacific): (3G0)407-6300 These numbers are also listed at the following web site: http:Uwww.ecv.wa.�ov/programs/wq/stonnwater/construction/perm it.htm 1 ii. Review the SWPPP for compliance with Special Condition S9 and make � appropriate revisions within 7 days of the date the discharge exceeded the benchmark. iii. Immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible, addressing the problems within 10 days of the date the discharge exceeded the benchmark. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when the Permittee requests an extension within the initial 10-day response period. iv. Document BMP implementation and maintenance in the site log book. v. Continue to sample discharges daily until: a) Turbidity is 25 NTU(or lower); or b) Transparency is 33 cm(or greater); or c) The Permittee has demonstrated compliance with the water quality limit for turbidity: 1) No more than 5 NTU over background turbidity, if background is less than 50 NTU, or 2) No more than 10%over background turbidity, if background is 50 NTU or greater; or d) The discharge stops or is eliminated. D. pH Sampling Requirements -- Si�nificant Concrete Work or Engineered Soils If construction activity results in the disturbance of 1 acre or more, and involves significant concrete work (significant concrete work means greater than 1000 cubic yards poured concrete or recycled concrete used over the life of a project) or the use of engineered soils (soil amendments including but not limited to Portland cement-treated base [CTB], cement kiln dust [CKD], or fly ash), and stormwater from the affected area Construction Stormwater General Permit—December 1, 2010 Page 17 drains to surface waters of the State or to a storm sewer system that drains to surface waters of the state,the Permittee must conduct pH monitoring as set forth below. Note: In addition, discharges to segments of water bodies on Washington State's 303(d) list (Category 5) for high pH are subject to a numeric effluent limit for pH; refer to Special Condition S8. 1. For sites with significant concrete work,the Permittee must begin the pH monitoring period when the concrete is first poured and exposed to precipitation, and continue weekly throughout and after the concrete pour and curing period, until stormwater pH is in the range of 6.5 to 8.5 (su). 2. For sites with engineered soils, the Permittee must begin the pH monitoring period when the soil amendments are first exposed to precipitation and must continue until the area of engineered soils is fully stabilized. , 3. During the applicable pH monitaring period defined above, the Permittee must �� obtain a representative sample of storm��ater and conduct pH analysis at least once per week. 4. The Permittee must monitor pH in the sediment trap/pond(s) or other locations that receive stormwater runoff from the area of significant concrete �y�ork or engineered soils before the stormwater discharges to surface waters. � 5. The benchmark value for pH is 8.5 standard units. Any-time sampling indicates that pH is 8.5 or greater, the Permittee must either: a. Prevent the high pH water(8.5 or above) from entering storm se��er systems or surface waters; or b. If necessary, adjust or neutralize the high pH «�ater until it is in the range of pH 6.5 to 8.5 (su) using an appropriate treatment BMP such as carbon dioxide (COZ) sparging or dry ice. The Permittee must obtain written approval from Ecology before using any form of chemical treatment other than COZ sparging or dry ice. 6. The Permittee must perform pH analysis on site with a calibrated pH meter, pH test kit, or wide range pH indicator paper. The Permittee must record pH monitoring results in the site log book. Construction Stormtivater General Perniit Decefrzbef• 1, 2010 Page 18 S5. REPORTING AND RECORDKEEPING REQUIREMENTS A. Hi�h Turbiditv Phone Reporting Anytime sampling performed in accordance with Special Condition S4.0 indicates turbidity has reached the 250 NTU phone reporting level, the Permittee must call Ecology's Regional office by phone within 24 hours of analysis. The web site is http://www.ecv.wa.gov/pro�rams/w�/stormwater/construction/permit.html. Also see phone numbers in Special Condition S4.C.S.b.i. B. Discharge Monitorin�Reports Permittees required to conduct water qualiry sampling in accordance with Special Conditions S4.0 (Turbidity/Transparency), S4.D (pH), S8 (303[d]/TMDL sampling), and/or G13 (Additional Sampling) must submit the results to Ecology. Permittees must submit monitoring data using Ecology's WebDMR program. To find out more information and to sign up for WebDMR go to: http://www.ecv.wa.gov/programs/wq/permits/paris/webdmr.htrnl. Permittees unable to submit electronically (for example, those who do not have an internet connection)must contact Ecology to request a��aiver and obtain instructions on how to obtain a paper copy DMR at: Mailing Address: Department of Ecology ' Water Quality Program Attn: Stormwater Compliance Specialist PO Box 47696 Olympia, WA 98504-7696 Permittees who obtain a waiver not to use WebDMR must use the forms provided to them by Ecology; submittals must be mailed to the address above. Permittees shall submit DMR forms to be received by Ecology within 15 days following the end of each month. If there was no discharge during a given monitoring period, all Permittees must submit a DMR as required with "no discharge" entered in place of the monitoring results. For more information, contact Ecology staff using information provided at the following web site: httn://www.ecv.wa.�ov/pro�rams/spills/response/assistancesoil%20map.pdf C. Records Retention The Permittee must retain records of all monitoring information (site log book, sampling results, inspection reports/checklists, etc.), Stormwater Pollution Prevention Plan, and any other documentation of compliance with permit requirements for the entire life of the construction project and for a minimum of three years following the termination of permit coverage. Such information must include all calibration and maintenance records, and records of all data used to complete the application for this Construction Stormwater General Permit—December 1, 2010 Page 19 permit. This period of retention must be extended during the course of any unresolved litigation regarding the discharge of pollutants by the Permittee or when requested by Ecology. D. Recordin�Results For each measurement or sample taken, the Permittee must record the following information: 1. Date,place, method, and time of sampling or measurement. 2. The first and last name of the individual who performed the sampling or measurement. 3. The date(s) the analyses were performed. 4. The first and last name of the individual who performed the analyses. �. The analytical techniques or methods used. 6. The results of all analyses. E. Additional Monitorin� bv the Permittee If the Permittee monitors any pollutant more frequently than required by this permit using test procedures specified by Special Condition S4 of this permit, the results of this monitoring must be included in the calculation and reporting of the data submitted in the Permittee's DMR. ; F. Noncompliance Notification In the event the Permittee is unable to comply with any part of the terms and conditions of this permit, and the resulting noncompliance may cause a threat to human health or the environment, the Permittee must: 1. Immediately notify Ecology of the failure to comply by calling the applicable Regional office ERTS phone number (find at http://«n��.ec, .y��_a.�ov/pro_rams/spills/response/assistancesoil%20ma�pdfl or refer to Special Condition S4.C.S.b.i. 2. Immediately take action to prevent the discharge/pollution, or otherwise stop or correct the noncompliance, and, if applicable, repeat sampling and analysis of any noncompliance immediately and submit the results to Ecology within five (5) days of becoming aware of the violation. 3. Submit a detailed written report to Ecology within five (5) days, unless requested earlier by Ecology. The report must contain a description of the noncompliance, including exact dates and times, and if the noncompliance has not been corrected, the anticipated time it is expected to continue; and the steps taken or planned to reduce, eliminate, and prevent reoccurrence of the noncompliance. Construction Stormwater General Permit—December 1, 2010 Page 20 The Permittee must report any unanticipated bypass and/or upset that exceeds any effluent limit in the permit in accordance with the 24-hour reporting requirement contained in 40 C.F.R. 122.41(1)(6)). Compliance with these requirements does not relieve the Permittee from responsibility to maintain continuous compliance with the terms and conditions of this permit or the resulting liability for failure to comply. Refer to Section G14 of this permit for specific information regarding non-compliance. G. Access to Plans and Records 1. The Pernuttee must retain the following permit documentation(plans and records} on site, or within reasonable access to the site, for use by the operator or for on-site review by Ecology or the local jurisdiction: a. General Permit. b. Pernut Coverage Letter. c. Stormwater Pollution Prevention Plan(SWPPP). d. Site Log Book. 2. The Permittee must address written requests for plans and records listed above (Special Condition SS.G.1) as follows: a. The Permittee must provide a copy of plans and records to Ecology within 14 days of receipt of a written request from Ecology. b. The Permittee must provide a copy of plans and records to the public when requested in writing. Upon receiving a written request from the public for the Permittee's plans and records, the Permittee must either: i. Provide a copy of the plans and records to the requester within 14 days of a receipt of the written request; or ii. �lotify the requester within 10 days of receipt of the written request of the ', location and times within normal business hours when the plans and records may be viewed; and provide access to the plans and recards «�ithin 14 days of receipt of the��vritten request; ar Within 14 days of receipt of the written request, the Permittee may submit a copy of the plans and records to Ecology for viewing and/or copying by the requester at an Ecology office, or a mutually agreed location. If plans and records are viewed and/or copied at a location other than at an Ecology office,the Permittee will provide reasonable access to copying services for which a reasonable fee may be charged. The Permittee must notify the requester within 10 days of receipt of the request where the plans and records may be viewed and/or copied. Construction Stornnvatej-General Permit—Decen�rbei• 1, 2010 Page 21 S6. PERMIT FEES The Permittee must pay permit fees assessed by Ecology. Fees for stormwater discharges covered under this permit are established by Chapter 173-224 WAC. Ecology continues to assess permit fees until the permit is terminated in accordance with Special Condition S10 or revoked in accordance��ith General Condition G5. S7. SOLID AND LIQUID WASTE DISPOSAL The Permittee must handle and dispose of solid and liquid wastes generated by construction activity, such as demolition debris, construction materials, contaminated materials, and ��aste materials from maintenance activities, including liquids and solids from cleaning catch basins and other stormwater facilities, in accordance with: A. Special Condition S3, Compliance with Standards. B. WAC 173-216-110. C. Other applicable regulations. S8. DISCHARGES TO 303(D) OR TMDL WATER BODIES A. Samplin� and Numeric Effluent Limits For Certain Discharges to 303(d)-listed Water Bodies 1. Permittees who discharge to segments of water bodies listed as impaired by the State of Washington under Section 303(d) of the Clean Water Act for turbidity, fine sediment, high pH, or phosphorus, must conduct water quality sampling according to the requirements of this section, and Special Conditions S4.C.2.b-f and S4.C.3.b-d, and must comply with the applicable numeric effluent limitations in S8.0 and S8.D. 2. All references and requirements associated with Section 303(d) of the Clean Water Act mean the most cunent listing by Ecology of impaired waters (Category 5)that exists on January 1, 201 l, or the date when the operator's complete permit application is received by Ecology, whichever is later. B. Limits on Covera�e for New Dischar�es to TMDL or 303(d)-listed Waters Operators of construction sites that discharge to a 303(d)-listed ��ater body are not eligible for coverage under this permit unless the operator: 1. Prevents exposing stormwater to pollutants for which the water body is impaired, and retains documentation in the SWPPP that details procedures taken to prevent exposure on site; or 2. Documents that the pollutants for which the water body is impaired are not pi�esent at the site, and retains documentation of this finding within the SWPPP; or Construction Stormwater General Per•nzit-- Decernbet- 1, 2010 Page 22 3. Provides Ecology with data indicating the discharge is not expected to cause or contribute to an exceedance of a water quality standard, and retains such data on site with the SWPPP. The operator must provide data and other technical I information to Ecology that sufficiently demonstrate: a. For discharges to waters without an EPA-approved or -established TMDL, that the discharge of the pollutant for which the water is impaired will meet in-stream water quality criteria at the point of discharge to the water body; or b. For discharges to waters with an EPA-approved or-established TMDL,that there is sufficient remaining wasteload allocation in the TMDL to allow construction stormwater discharge and that existing dischargers to the water body are subject to compliance schedules designed to bring the water body into attainment with water quality standards. Operatars of construction sites are eligible for coverage under this permit if Ecology issues permit coverage based upon an affirmative determination that the dischar�e will not cause or contribute to the existing impairment. C. Samplin� and Numeric Effluent Limits for Dischar�es to Water Bodies on the 303(d) List for Turbiditv, Fine Sediment, or Phosphorus 1. Permittees who discharge to segments of«-ater bodies on the 303(d) list (Category 5) for turbidity, fine sediment, or phosphorus must conduct turbidity sampling in accordance with Special Condition S4.C.2 and comply«ith either of the numeric effluent limits noted in Table 5 beloc�. 2. As an alternative to the 25 NTiJ effluent limit noted in Table � below(applied at the point where stormwater [or authorized non-storinwater] is discharged off-site), permittees may choose to comply with the surface water quality standard for turbidity. The standard is: no more than 5 NTU over background turbidity when the background turbidity is 50 NTU or less, or no more than a 10% increase in turbidity when the background turbidity is more than 50 NTU. In order to use the water quality standard requirement, the sampling must take place at the follo��inb locations: a. Background turbidity in the 303(d)-listed receiving��ater immediately upstream(upgradient) or outside the area of influence of the discharge. b. Turbidity at the point of discharge into the 303(d)-listed receiving ��ater, inside the area of influence of the discharge. 3. Discharges that exceed the numeric effluent limit for turbidity constitute a violation of this permit. 4. Permittees vvhose discharges exceed the ntmieric effluent limit shall samplc discharges daily until the violation is corrected and comply�vith the non- compliance notitication requirements in Special Condition S�.F. Constf-uction Stormwater Genet•al Per�mit- Decernbe�- 1, 2010 Page 23 Tabie 5. Turbidity, Fine Sediment & Phosphorus Sampling and Limits for 303(d)-Listed Waters Parameter identified Parameter Unit Analytical Sampling Numeric Effluent in 303(d) listing Sampled Method Frequency Limit� • Turbidity Turbidity NTU SM2130 or Weekly, if 25 NTU, at the point I • Fine Sediment EPA180.1 discharging where stormwater is ' . Phosphorus discharged from the site;OR In compliance with the surface water quality standard for turbidity (S8.C.1.a) 'Permittees subject to a numeric effluent limit for turbidity may, at their discretion,choose either numeric effluent limitation based on site-specific considerations including, but not limited to,safety, access and convenience. D. Dischar�es to Water Bodies on the 303(d) List for Hi�h pH I l. Permittees who discharge to segments of water bodies on the 303(d) list (Category 5) for high pH must conduct pH sampling in accordance with the table belo��, and comply with the numeric effluent limit of pH 6.5 to 8.5 su (Table 6). Table 6. pH Sampling and Limits for 303(d)-Listed Waters Parameter identified in Parameter Analytical Sampling Numeric Effluent 303(d) listing SampledlUnits Method Frequency Limit High pH pH /Standard pH meter Weekly, if In the range of 6.5— Units discharging 8.5 2. At the Permittee's discretion, compliance��rith the limit shall be assessed at one of the following locations: a. Directly in the 303(d)-listed��-ater body segment, inside the immediate area of influence of the discharge; or b. Alternatively, the permittee may measure pH at the point��here the discharge leaves the construction site, rather than in the receiving«ater. 3. Discharges that exceed the numeric effluent limit for pH (outside the range of 6.5 — 8.5 su) constitute a violation of this permit. 4. Permittees«�hose discharges exceed the numeric effluent limit shall sample discharges daily until the violation is corrected and comply with the non- compliance notification requirements in Special Condition SS.F. Construction Stormlvater General Pef•rnit— Decernber• 1, 2010 Page 24 E. Sampling and Limits for Sites Dischar�ing to Waters Covered bv a TMDL or Another Pollution Control Plan 1. Discharges to a water body that is subject to a Total Maximum Daily Load ' (TMDL) for turbidity, fine sediment, high pH, or phosphorus must be consistent with the TMDL. Refer to http://www.ecy.��a.�ov/programs/wq/tmdl/index.html foi• more information on TMDLs. a. Where an applicable TMDL sets specific ��aste load allocations or requirements for discharges covered by this permit, discharges must be consistent with any specific waste load allocations or requirements established by the applicable TMDL. i. The Pernuttee must sample discharges weekly or as otherwise specified by the TMDL to evaluate compliance with the specific waste load allocations or requirements. ii. Analytical methods used to meet the monitoring requirements must conform to the latest revision of the Guidelines Establishing Test Procedures for the Analysis of Pollutants contained in 40 CFR Part 136. Turbidity and pH methods need not be accredited or registered unless conducted at a laboratory �vhich must other��ise be accredited or registered. b. Where an applicable TMDL has established a general �vaste load allocation for construction stormwater discharges, but has not identified specific requirements, compliance with Special Conditions S4 (Monitoring) and S9 (SWPPPs)will constitute compliance with the approved TNIDL. c. Where an applicable TMDL has not specified a waste load allocation for construction stormwater discharges, but has not excluded these discharges, compliance with Special Conditions S4 (Monitoring) and S9 (SWPPPs) will constitute compliance with the approved TMDL. d. Where an applicable TMDL specifically precludes or prohibits discharges from construction activity, the operator is not eligible for coverage under this permit. 2. Applicable TMDL means a TMDL for turbidity, fine sediment, high pH, or phosphorus that is completed and approved by EPA before January 1, 2011, or before the date the operator's complete permit application is received by Ecology, whichever is later. T1VIDLs completed after the operator's complete permit application is received by Ecology become applicable to the Permittee only if they are imposed through an administrative order by Ecology, or through a modification of permit coverave. Construction Storrmvater General Permit—Deceniber• 1, 2010 Page 25 S9. STORMWATER POLLUTION PREVENTION PLAN The Permittee must prepare and properly implement an adequate Stormwater Pollution Prevention Plan (SWPPP) for construction activity in accordance writh the requirements of this permit beginning with initial soil disturbance and until final stabilization. A. The Permittee's SWPPP must meet the following objectives: 1. To implement best management practices (BMPs) to prevent erosion and sedimentation, and to identify, reduce, eliminate or prevent stormwater contamination and water pollution from construction activity. 2. To prevent violations of surface water quality, ground water quality, or sediment management standards. 3. To control peak volumetric flow rates and velocities of stormwater discharges. B. General Requirements 1. The SWPPP must include a narrative and drawings. All BMPs must be clearly referenced in the narrative and marked on the drawings. The SWPPP narrative must include documentation to explain and justify the pollution prevention decisions made for the project. Documentation must include: a. Information about existing site conditions (topography, drainage, soils, vegetation, etc.). b. Potential erosion problem areas. c. The 12 elements of a SWPPP in Special Condition S9.D.1-12, including BMPs used to address each element. d. Construction phasing/sequence and general BMP implementation schedule. e. The actions to be taken if BMP performance goals are not achieved—for example, a contingency plan for additional treatment and/or storage of stormwater that would violate the water quality standards if discharged. I f. Engineering calculations for ponds and any other designed structures. 2. The Permittee must modify the SWPPP if, during inspections or investigations conducted by the owner/operator, or the applicable local or state regulatory authority, it is determined that the SWPPP is, or would be, ineffective in eliminating or significantly minimizing pollutants in stormwater discharges from the site. The Permittee must then: a. Review the SWPPP for compliance with Special Condition S9 and make appropriate revisions within 7 days of the inspection or investigation. b. Immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible, addressing the problems no later than 10 days from the inspection or investigation. If Construction Stormwater General Permit–December 1, 2010 Page 26 installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when an extension is requested by a Permittee within the initial 10-day response period, c. Document BMP implementation and maintenance in the site log book. The Permittee must modify the SWPPP whenever there is a change in design, construction, operation, or maintenance at the construction site that has, or could have,a significant effect on the discharge of pollutants to waters of the State. C. Stormwater Best Mana�ement Practices (BMPs) BMPs must be consistent with: 1. Stormwater Management Manual for Western Washington(most recent edition), for sites west of the crest of the Cascade Mountains; or 2. Stormwater Management Manual for Eastern Washington (most recent edition), for sites east of the crest of the Cascade Mountains; or 3. Revisions to the manuals listed in Special Condition S9.C.1. & 2., or other stormwater management guidance documents or manuals which provide an equivalent level of pollution prevention,that are approved by Ecology and incorporated into this permit in accordance with the permit modification ' requirements of WAC 173-226-230; or 4. Documentation in the SWPPP that the BMPs selected provide an equivalent level of pollution prevention, compared to the applicable Stormwater Management Manuals, including: a. The technical basis for the selection of all storin��ater BMPs (scientific, technical studies, and/or inodeling) that support the perfonnance claims for the BMPs being selected. b. An assessment of how the selected BMP ��-i11 satisfy AKART requirements and the applicable federal technology-based treatment requirements under 40 CFR part 125.3. D. SWPPP—Narrative Contents and Requirements The Permittee must include each of the 12 elements below-in Special Condition S9.D.1- 12 in the narrative of the SWPPP and implement them unless site conditions render the element unnecessary and the exemption from that element is clearly justified in the SWPPP. 1. Preserve Vegetation/Mark Clearing Limits a. Before beginning land-disturbing activities, including clearing and grading, clearly mark all clearing limits, sensitive areas and their buffers, and trees that are to be preserved��vithin the construction area. Construction Storrnwater General Per�rnit—Deceryiber 1, 2010 Page 27 b. Retain the duff layer,native top soil, and natural vegetation in an undisturbed state to the maximum degree practicable. 2. Establish Construction Access a. Limit construction vehicle access and exit to one route, if possible. b. Stabilize access points with a pad of quarry spalls, crushed rock, or other equivalent BMPs,to minimize tracking sediment onto roads. c. Locate wheel wash or tire baths on site, if the stabilized construction entrance is not effective in preventing tracking sediment onto roads. d. If sediment is tracked off site, clean the affected roadway thoroughly at the end of each day,or more frequently as necessary(for example, during wet weather). Remove sediment from roads by shoveling, sweeping, or pickup and transport of the sediment to a controlled sediment disposal area. e. Conduct street washing only after sediment removal in accordance with Special Condition S9.D.2.d. Control street wash wastewater by pumping back on site or otherwise preventing it from discharging into systems tributary to�vaters of the State. 3. Control Flow Rates a. Protect properties and waterways downstream of development sites from erosion and the associated discharge of turbid waters due to increases in the velocity and peak volumetric flow rate of storm«�ater runoff from the project site, as required by local plan approval authority. b. Where necessary to comply with Special Condition S9.D.3.a, construct stormwater retention or detention facilities as one of the first steps in grading. Assure that detention facilities function properly before constnicting site improvements (for example, impervious surfaces). c. If permanent infiltration ponds are used for flow contt•ol during construction, protect these facilities from siltation during the construction phase. 4. Install Sediment Controls The Permittee must design, install and maintain effective erosion controls and sediment controls to minimize the discharge of pollutants. At a minimum, the Permittee must design, install and maintain such controls to: a. Construct sediment control BMPs (sediment ponds,traps, filters, etc.) as one of the first steps in grading. These BMPs must be functional before other land disturbing activities take place. b. Minimizc sedimcnt discharges from the site. The design, installation and maintenance of erosion and sediment controls must address factors such as the amount, frequency, intensity and duration of precipitation,the nature of Construction Stormwater General Perrnit—Decernber 1, 2010 Page 28 resulting stormwater runoff, and soil characteristics, including the range of soil particle sizes expected to be present on the site. c. Direct stormwater runoff from disturbed areas through a sediment pond or other appropriate sediment removal BMP, before the runoff leaves a construction site or before discharge to an infiltration facility. Runoff from fully stabilized areas may be discharged without a sediment removal BMP, but must meet the flow control performance standard of Special Condition S9.D.3.a. d. Locate BMPs intended to trap sediment on site in a manner to avoid interference with the movement of juvenile salmonids attempting to enter off- channel areas or drainages. e. Provide and maintain natural buffers around surface waters, direct stormwater to vegetated areas to increase sediment removal and maximize stormwater infiltration,unless infeasible. f. Where feasible, design outlet structures that withdraw impounded stormwater from the surface to avoid discharging sediment that is still suspended low�er in the water column. 5. Stabilize Soils a. The Permittee must stabilize exposed and unworked soils by application of effective BMPs that prevent erosion. Applicable BMPs include, but are not limited to:temporary and permanent seeding, sodding, mulching, plastic covering, erosion control fabrics and matting, soil application of polyacrylamide (PAM), the early application of gravel base on areas to be paved, and dust control. b. The Permittee must control stornzwater volume and��elocity within the site to minimize soil erosion. c. The Permittee must control stoi-�n��-�ater discharges, including both peak flo�� rates and total stormwater volume,to minimize erosion at outlets and to minimize downstream channel and stream bank erosion. d. Depending on the geographic location of the project, the Permittee must not allow soils to remain exposed and unworked for more than the time periods set forth below to prevent erosion: West of the Cascade Mountains Crest During the dry season(May 1 - Sept. 30): 7 da5-s During the wet season (October 1 - Apri130): 2 days East of the Cascade Mountains Crest, except for Central Basin" During the dry season (July 1 - September 30): 10 days During the wet season (October 1 - June 30): 5 days The Central Basin�`, East of the Cascade Mountains Crest Constr•uction Stormtivate�• General Per�iiit—Decef�rber� 1, 2010 Page 29 During the dry Season(July 1 - September 30): 30 days During the wet season (October 1 - June 30): 15 days *Note: The Central Basin is defined as the portions of Eastern Washington with mean annual precipitation of less than 12 inches. e. The Permittee must stabilize soils at the end of the shift before a holiday ar weekend if needed based on the weather forecast. f. The Permittee must stabilize soil stockpiles from erosion,protected with sediment trapping measures, and where possible, be located away from storm drain inlets, waterways, and drainage channels. g. The Permittee must minimize the amount of soil exposed during construction activity. h. The Permittee must minimize the disturbance of steep slopes. i. The Permittee must minimize soil compaction and,unless infeasible,preserve topsoil. 6. Protect Slopes a. The Permittee must design and construct cut-and-fill slopes in a manner to minimize erosion. Applicable practices include, but are not limited to, reducing continuous length of slope with terracing and diversions,reducing slope steepness, and roughening slope surfaces(for example,track walking). b. The Permittee must divert off-site stormwater(run-on)or ground water away from slopes and disturbed areas with interceptor dikes,pipes, and/or swales. Off-site stormwater should be managed separately from stormwater generated on the site. c. At the top of slopes, collect drainage in pipe slope drains or protected channels to prevent erosion. i. West of the Cascade Mountains Crest: Temporary pipe slope drains must handle the peak 10-minute velocity of flow from a Type 1 A, 10-year, 24- hour frequency storm for the developed condition. Alternatively, the 10- year, 1-hour flow rate predicted by an approved continuous runoff model, increased by a factor of 1.6, may be used. The hydrologic analysis must use the existing land cover condition for predicting flow rates from tributary areas outside the project limits. For tributary areas on the project site, the analysis must use the temporary or permanent project land cover condition, whichever will produce the highest flow rates. If using the Western Washington Hydrology Model (WWH1Vn to predict flo`�s, bare soil areas should be modeled as "landscaped area." Construction Stormtivater General Pes�mit—December• 1, 2010 Page 30 ii. East of the Cascade Mountains Crest: Temporary pipe slope drains must handle the expected peak flow velocity from a 6-month, 3-hour storm for the developed condition, referred to as the short duration storm. d. Place excavated material on the uphill side of trenches, consistent with safety and space considerations. e. Place check dams at regular intervals within constructed channels that are cut down a slope. 7. Protect Drain Inlets a. Protect all storm drain inlets made operable during construction so that stormwater runoff does not enter the conveyance system without first being filtered or treated to remove sediment. ' b. Clean or remove and replace inlet protection devices when sediment has filled I one-third of the available storage (unless a different standard is specified by the product manufacturer). 8. Stabilize Channels and Outlets a. Design, construct and stabilize all on-site conveyance channels to prevent erosion from the following expected peak flows: i. West of the Cascade Mountains Crest: Channels must handle the peak 10- minute velocity of flow from a Type lA, 10-year,24-hour frequency storm for the developed condition.Alternatively,the 10-year, 1-hour flow rate indicated by an approved continuous runoff model, increased by a factor of 1.6,may be used. The hydrologic analysis must use the existing land cover condition for predicting flow rates from tributary areas outside the project limits.For tributary areas on the project site,the analysis must use the temporary or permanent project land cover condition,whichever will produce the highest flow rates. If using the WWHM to predict flo«rs,bare soil areas should be modeled as "landscaped area." ii. East of the Cascade Mountains Crest: Channels must handle the expected peak flow velocity from a 6-month, 3-hour storm for the developed condition,referred to as the short duration storm. b. Provide stabilization,including armaring material, adequate to prevent erosion of outlets, adjacent stream banks, slopes, and downstream reaches at the outlets of all conveyance systems. 9. Control Pollutants Design, install, implement and maintain effective pollution prevention rneasures to minimize the discharge of pollutants. The Permittee must: Construction Stormtivater General Permit—Dece�siber� 1, 2010 Page 31 a. Handle and dispose of all pollutants, including waste materials and demolition debris that occur on site in a manner that does not cause contamination of stormwater. b. Provide cover,containment, and protection from vandalism for all chemicals, liquid products,petroleum products, and other materials that have the potential to pose a threat to human health or the environment. On-site fueling tanks must i include secondary containment. Secondary containment means placing tanks or containers within an impervious structure capable of containing 110%of the volume contained in the largest tank within the containment structure. Double- walled tanks do not require additional secondary containment. c. Conduct maintenance,fueling, and repair of heavy equipment and vehicles using spill prevention and control measures. Clean contaminated surfaces immediately following any spill incident. d. Discharge�vheel wash or tire bath wastewater to a separate on-site treatment system that prevents discharge to surface water, such as closed-loop recirculation or upland land application, or to the sanitary se��er��ith local sewer district approval. e. Apply fertilizers and pesticides in a manner and at application rates that will not result in loss of chemical to stormwater runoff. Follow manufacturers' label requirements for application rates and procedures. f. Use BMPs to prevent contamination of stormwater runoff by pH-modifying sources. The sources for this contamination include, but are not limited to: bulk cement, cement kiln dust, fly ash,new concrete washing and curing waters, waste streams generated from concrete grinding and sawing, exposed aggregate processes, dewatering concrete vaults,concrete pumping and mixer washout waters. (Also refer to the definition for "concrete wastewater" in Appendix A-- Definitions.) g. Adjust the pH of stormwater if necessary to pt•event violations of��ater quality standards. h. Assure that��-ashout of concrete trucks is perfor-�i1ed offsite or in designated concrete washout areas only. Do not wash out concrete trucks onto the ground, or into storm drains, open ditches, streets,or streams. Do not dump excess concrete on site,except in designated concrete washout areas. Concrete spillage or concrete discharge to surface waters of the State is prohibited. i. Obtain written approval from Ecology befare using chemical treatrnent other than CO2 or dry ice to adjust pH. 10. Control Dewatering a. Permittees must discharge foundation, ��ault, and trench de�vatering water, which have characteristics similar to storm�vater runoff at the site, into a Construction Storrnwater General Perr77it—Decerylber 1, 2010 Page 32 controlled conveyance system before discharge to a sediment trap or sediment pond. b. Permittees may discharge clean, non-turbid dewatering water, such as well- point ground water,to systems tributary to, or directly into surface waters of the State, as specified in Special Condition S9.D.8,provided the dewatering flow does not cause erosion or flooding of receiving waters. Do not route clean dewatering water through stormwater sediment ponds. Note that"surface waters of the State" may exist on a construction site as well as off site; for example, a creek running through a site. c. Other treatment or disposal options may include: i. Infiltration. ii. Transport off site in a vehicle, such as a vacuum flush truck, for legal disposal in a manner that does not pollute state waters. iii. Ecology-approved on-site chemical treatment or other suitable treatment technologies. iv. Sanitary or combined sewer discharge with local sewer district approval, if there is no other option. v. Use of a sedimentation bag with discharge to a ditch or swale for small volumes of localized dewatering. � d. Permittees must handle highly turbid or contaminated dewatering water separately from stormwater. 11. Maintain BMPs a. Permittees must maintain and repair all temporary and permanent erosion and sediment control BMPs as needed to assure continued performance of their intended function in accordance with BMP specifications. b. Pernuttees must remove all temporary erosion and sediment control BMPs within 30 days after achieving final site stabilization or after the temporary BMPs are no longer needed. 12. Manage the Project a. Phase development projects to the ma�cimum degree practicable and take into account seasonal work limitations. b. Inspection and monitoring -- Inspect, maintain and repair a11 BMPs as needed to assure continued performance of their intended function. Conduct site inspections and monitoring in accordance with Special Condition S�}. c. Maintaining an updated construction SWPPP --Maintain,update, and implement the SWPPP in accordance��th Special Conditions S3, S� and S9. Construction Stormwater GeneYal Per�nait— December� 1, 2010 Page 33 !`•':ys� .+; � �4. . . .. _ . -. . if � '� -��A '�5 '- � . .. ' . . .. . . . .. E. SWPPP— Map Contents and Requirements The Permittee's SWPPP must also include a vicinity map or general location map (for example, a USGS quadrangle map, a portion of a county or city map, or other appropriate map)with enough detail to identify the location of the construction site and receiving waters within one mile of the site. The SWPPP must also include a legible site map (or maps) showing the entire construction site. The follo��ing features must be identified, unless not applicable due to site conditions: 1. The direction of north,property lines, and existing structures and roads. 2. Cut and fill slopes indicating the top and bottom of slope catch lines. 3. Approximate slopes, contours, and direction of stormwater flow before and atter major grading activities. 4. Areas of soil disturbance and areas that will not be disturbed. 5. Locations of structural and nonstructural controls (BMPs) identified in the SWPPP. 6. Locations of off-site material, stockpiles, «�aste storage, bono«- areas, and vehicle/equipment storage areas. 7. Locations of all surface water bodies, including wetlands. 8. Locations where stormwater or non-stormwater discharges off-site and/or to a surface water body, including wetlands. 9. Location of water quality sampling station(s), if sampling is required by state or local permitting authority. 10. Areas where final stabilization has been accomplished and no further construction- phase permit requirements apply. 510. NOTICE OF TERMINATION A. The site is eligible for termination of co��erage��hen it has met any of the follo��ing -" conditions: 1. The site has undergone final stabilization, the Pennittee has removed all temporary BMPs (except biodegradable BMPs clearly manufactured with the intention for the material to be left in place and not interfere with maintenance or land use), and all storm«�ater discharges associated�vith consh�uction activity have been eliminated; or 2. All portions of the site that have not undergone final stabilization per Special Condition S 10.A.1 have been sold and/or transferred(per General Condition G9), and the Permittee no longer has operational control of the construction activity; or Construction Stormtivater General Pef•rnit—Decernber 1, 2010 Page 3� 3. For residential construction only, the Permittee has completed temporary stabilization and the homeowners have taken possession of the residences. B. When the site is eligible for termination,the Permittee must submit a complete and accurate Notice of Termination(NOT) form, signed in accordance with General Condition G2,to: Department of Ecology Water Quality Program - Construction Stormwater PO Box 47696 Olympia, Washington 98504-7696 The termination is effective on the date Ecology receives the NOT form, unless Ecology notifies the Permittee within 30 days that termination request is denied because the Permittee has not met the eligibility requirements in Special Condition S10.A. Permittees transferring the property to a new property owner or operator/permittee are required to complete and submit the Notice of Transfer form to Ecology, but are not required to submit a Notice of Ternunation form for this type of transaction. Construction Stormwater General Pef-mit—Decenaber 1, 2010 Page 35 GENERAL CONDITIONS G1. DISCHARGE VIOLATIONS All discharges and activities authorized by this general permit must be consistent with the terms and conditions of this general permit. Any discharge of any pollutant more frequent than or at a level in excess of that identified and authorized by the general permit must constitute a violation of the terms and conditions of this permit. G2. SIGNATORY REQUIREMENTS A. All permit applications must bear a certification of correctness to be signed: 1. In the case of corporations, by a responsible corporate officer of at least the level of vice president of a corporation; 2. In the case of a partnership, by a general partner of a partnership; 3. In the case of sole proprietorship, by the proprietor; or 4. In the case of a municipal, state, or other public facility, by either a principal executive officer or ranking elected official. B. All reports required by this permit and other information requested by Ecology must be signed by a person described above or by a duly authorized representative of that person. A person is a duly authorized representative only if: 1. The authorization is made in writing by a person described above and submitted to the Ecology. 2. The authorization specifies either an individual or a position having responsibility for the overall operation of the regulated facility, such as the position of plant manager, superintendent,position of equivalent responsibility, or an individual or position having overall responsibility for environmental matters. C. Changes to authorization. If an authorization under paragraph G2.B.2 above is no longer accurate because a different individual or position has responsibility for the overall operation of the facility, a new authorization satisfying the requirements of paragraph G2.B.2 above must be submitted to Ecology prior to or together with any reports, information, or applications to be signed by an authorized representative. D. Certification. Any person signing a document under this section must inake the following certification: "I certify under penalty of law, that this document and all attachments ��ere prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gathered and evaluated the information submitted. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering Construction Stornnvater Genef•al Per•mit—Decembes• 1, 2010 Page 36 information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations." G3. RIGHT OF INSPECTION AND ENTRY The Permittee must allow an authorized representative of Ecology, upon the presentation of credentials and such other documents as may be required by law: A. To enter upon the premises where a discharge is located or where any records are kept under the terms and conditions of this permit. B. To have access to and copy—at reasonable times and at reasonable cost -- any records required to be kept under the terms and conditions of this permit. C. To inspect-- at reasonable times—any facilities, equipment(including monitoring and control equipment), practices,methods, or operations regulated or required under this permit. D. To sample or monitor—at reasonable times —any substances or parameters at any location for purposes of assuring permit compliance or as otherwise authorized by the Clean Water Act. G4. GENERAL PERMIT MODIFICATION AND REVOCATION I This permit may be modified, revoked and reissued, or terminated in accordance with the provisions of Chapter 173-226 WAC. Grounds for modification, revocation and reissuance, or termination include, but are not limited to,the following: A. When a change occurs in the technology or practices for control or abatement of pollutants applicable to the category of dischargers covered under this permit. B. When effluent limitation guidelines or standards are promulgated pursuant to the CWA or Chapter 90.48 RCW, for the category of dischargers covered under this permit. C. When a water quality management plan containing requirements applicable to the category of dischargers covered under this permit is approved, or D. When information is obtained that indicates cumulative effects on the environment from dischargers covered under this permit are unacceptable. G5. REVOCATION OF COVERAGE UNDER THE PERMIT Pursuant to Chapter 43.21B RCW and Chapter 173-226 WAC, the Director may terminate coverage for any discharger under this permit for cause. Cases where coverage may be terminated include, but are not limited to, the follo�ving: Constt-uction Stormtivater Genernl Perrrtit—Decernbe�� 1, 2010 Page 3 7 A. Violation of any term or condition of this permit. B. Obtaining coverage under this permit by misrepresentation or failure to disclose fully all relevant facts. C. A change in any condition that requires either a temporary or permanent reduction or elimination of the permitted discharge. D. Failure or refusal of the Permittee to allow entry as required in RCW 90.48.090. E. A determination that the permitted activity endangers human health or the environment, or contributes to ti�ater quality standards violations. F. Nonpayment of permit fees or penalties assessed pursuant to RCW 90.48.465 and Chapter 173-224 WAC. G. Failure of the Permittee to satisfy the public notice requirements of WAC 173-226- 130(5), when applicable. The Director may require any discharger under this permit to apply for and obtain coverage under an individual permit or another more specific general permit. Permittees who have their coverage revoked for cause according to WAC 173-226-240 may request temporary coverage under this permit during the time an individual permit is being developed, provided the request is made within ninety (90) days from the time of revocation and is submitted along with a complete individual permit application form. G6. REPORTING A CAUSE FOR MODIFICATION The Permittee must submit a new application, or a supplement to the previous application, whenever a material change to the construction activity or in the quantity or type of discharge is anticipated which is not specifically authorized by this permit. This application must be submitted at least sixty(60) days prior to any proposed changes. Filing a request for a permit modification, revocation and reissuance, or termination, or a notification of planned changes or anticipated noncompliance does not relie��e the Permittee of the duty to comply�vith the existing permit until it is modified or reissued. G7. COMPLIANC� �'�'ITH OTHER LAWS AND STATUTES Nothing in this permit will be construed as excusing the Permittee from coinpliance �;�ith any applicable federal, state, or local statutes, ordinances, or regulations. GS. DUTY TO REAPPLY The Permittee must apply for permit rene��al at least 180 da}�s prior to the specified expiration date of this permit. Constr•uction Storrnwater General Per�rriit— Decesztber� 1, 2010 Page 3 8 G9. TRANSFER OF GENERAL PERMIT COVERAGE Coverage under this general permit is automatically transfened to a new discharger, including operators of lots/parcels within a common plan of development or sale, if: A. A written agreement(Transfer of Coverage Form) between the current discharger (Permittee) and new discharger, signed by both parties and containing a specific date for transfer of permit responsibility, coverage, and liability is submitted to the Director; and B. The Director does not notify the current discharger and new discharger of the Director's intent to revoke coverage under the general permit. If this notice is not given, the transfer is effective on the date specified in the written agreement. When a current discharger(Permittee)transfers a portion of a permitted site, the current discharger must also submit an updated application form (NOI)to the Director indicating the remaining permitted acreage after the transfer. G10. REMOVED SUBSTANCES The Permittee must not re-suspend or reintroduce collected screenings, grit, solids, sludges, filter backwash, or other pollutants removed in the course of treatment or control of storm��ater to the final effluent streain for discharge to state ��aters. G11. DUTY TO PROVIDE INFORMATION The Permittee must submit to Ecology, within a reasonable time, all information that Ecology may request to determine whether cause exists for modifying, revoking and reissuing, or terminating this permit or to determine compliance with this permit. The Permittee must also submit to Ecology, upon request, copies of records required to be kept by this permit [40 CFR 122.41(h)]. G12. OTHER REQUIREI��ZENTS OF 40 CFR All other requirements of 40 CFR 122.41 and 122.42 are incoiporated in this peimit by reference. G13. ADDITIONAL MONITORING Ecology may establish specific monitoring requirements in addition to those contained in this permit by administrative order or permit modification. Construction Stormwater General Pe��•mit—Decernber 1, 2010 Page 39 G14. PENALTIES FOR VIOLATING PERNIIT CONDITIONS Any person who is found guilty of willfully violating the terms and conditions of this permit shall be deemed guilty of a crime, and upon conviction thereof shall be punished by a fine of up to ten thousand dollars ($10,000) and costs of prosecution, or by imprisonment in the discretion of the court. Each day upon which a willful violation occurs may be deemed a separate and additional violation. Any person who violates the terms and conditions of a waste discharge permit shall incur, in addition to any other penalty as provided by law, a civil penalty in the amount of up to ten thousand dollars ($10,000) for every such violation. Each and every such violation shall be a separate and distinct offense, and in case of a continuing violation, every day's continuance shall be deemed to be a separate and distinct violation. G15. UPSET Definition—"Upset" means an exceptional incident in which there is unintentional and temporary noncompliance with technology-based permit effluent limitations because of factors beyond the reasonable control of the Permittee. An upset does not include noncompliance to the extent caused by operational error, improperly designed treatment facilities, inadequate treatment facilities, lack of preventive maintenance, or careless or improper operation. An upset constitutes an affirmative defense to an action brought for noncompliance with such technology-based permit effluent limitations if the requirements of the following paragraph are met. A Permittee who wishes to establish the affirmative defense of upset must demonstrate, through properly signed, contemporaneous operating logs or other relevant evidence that: 1) an upset occurred and that the Permittee can identify the cause(s) of the upset; 2) the permitted facility was being properly operated at the time of the upset; 3) the Permittee ' submitted notice of the upset as required in Special Condition SS.F, and; 4) the Permittee � complied with any remedial measures required under this permit. In any enforcement proceeding,the Permittee seeking to establish the occurrence of an upset has the burden of proof. G16. PROPERTY RIGHTS This permit does not convey any property rights of any sort, or any exclusive privilege. G17. DUTY TO COMPLY The Permittee must comply with all conditions of this permit. Any pernut noncompliance constitutes a violation of the Clean Water Act and is grounds for enforcement action; for permit termination, revocation and reissuance, or modification; ar denial of a pennit rene��al application. Construction Stormwate�General Perrnit—December 1, 2010 Page 40 G18. TOXIC POLLUTANTS The Permittee must comply with effluent standards or prohibitions established under Section 307(a) of the Clean Water Act for toxic pollutants within the time provided in the regulations that establish those standards or prohibitions, even if this permit has not yet been modified to incorporate the requirement. G19. PENALTIES FOR TAMPERING The Clean Water Act provides that any person who falsifies,tampers with, or knowingly renders inaccurate any monitoring device or method required to be maintained under this permit shall, upon conviction, be punished by a fine of not more than$10,000 per violation, or by imprisonment for not more than two years per violation, or by both. If a conviction of a person is for a violation committed after a first conviction of such person under this condition, punishment shall be a fine of not more than$20,000 per day of violation, or imprisonment of not more than four(4) years, or both. G20. REPORTING PLANNED CHANGES The Permittee must, as soon as possible, give notice to Ecology of planned physical alterations, modifications or additions to the permitted construction activity. The Permittee should be aware that, depending on the nature and size of the changes to the original permit, a new public notice and other permit process requirements may be required. Changes in activities that require reporting to Ecology include those that will result in: A. The permitted facility being determined to be a new source pursuant to 40 CFR 122.29(b). B. A significant change in the nature or an increase in quantity of pollutants discharged, including but not limited to: for sites 5 acres or larger, a 20% or greater increase in acreage disturbed by construction activity. C. A change in or addition of surface water(s)receiving stormwater or non-stormwater from the construction activity. D. A change in the construction plans and/or activity that affects the Permittee's monitoring requirements in Special Condition S4. Following such notice,permit coverage may be modified, or revoked and reissued pursuant to 40 CFR 122.62(a)to specify and limit any pollutants not previously limited. Until such modification is effective,any new or increased discharge in excess of permit limits or not specifically authorized by this permit constitutes a violation. Construction Stormwater General Permit—Decembe�� 1, 2010 Page 41 i G21. REPORTING OTHER INFORMATION Where the Permittee becomes aware that it failed to submit any relevant facts in a permit application, or submitted incorrect information in a permit application or in any report to Ecology, it must promptly submit such facts or information. G22. REPORTING ANTICIPATED NON-COMPLIANCE I The Pernuttee must give advance notice to Ecology by submission of a ne�v application or supplement thereto at least forty-five (45) days prior to commencement of such discharges, of any facility expansions, production increases, or other planned changes, such as process modifications, in the permitted facility or activity which may result in noncompliance with permit limits or conditions. Any maintenance of facilities, which might necessitate unavoidable interruption of operation and degradation of effluent quality, must be scheduled ijlll�lt��_T IZCill-�l'll(CCll ��ClTCl� ��UCl�ll\ �1�1'lil��S ❑ll�j C:lll'1Clj �1L11 1l1 <1 I]1<�1111C1� Cl�?��]-ll��lj IlV" ��C��l��'��. (�23. ll{� � '� , � , � � _ � , �', . °, � � , , _ ; . Any di� _ . . . ; _ the general permit by applying for an individual permit. The discharger must submit to the Director an application as described in WAC 173-220-040 or WAC 173-216-070, whichever is applicable, with reasons supporting the request. These reasons will fully document how an individual permit will apply to the applicant in a way that the general permit cannot. Ecology may make specific requests for information to support the request. The Director will either issue an individual permit or deny the request with a statement explaining the reason for the denial. When an individual permit is issued to a discharger otherwise subject to the construction stormwater general permit, the applicability of the construction stormwater general permit to that Permittee is automatically terminated on the effective date of the individual permit. G24. APPEALS A. The terms and conditions of this general permit, as they apply to the appropriate class of dischargers, are subject to appeal by any person within 30 days of issuance of this general permit, in accordance with Chapter 43.21 B RCW, and Chapter 173-226 WAC. B. The terms and conditions of this general permit, as they apply to an individual discharger, are appealable in accordance with Chapter 43.21 B RCW within 30 da}s of the effective date of coverage of that discharger. Consideration of an appeal of general permit coverage of an individual discharger is limited to the general permit's applicability or nonapplicability to that individual discharger. C. The appeal of general permit coverage of an individual dischat�ger does not aftect an5r other dischargers covered under this general permit. If the terms and conditions of this general permit are found to be inapplicable� to any individual discharger(s), the matter Construction Stormwater General Perrnit—Decernber 1, 2010 Page 42 shall be remanded to Ecology for consideration of issuance of an individual permit or permits. G25. SEVERABILITY The provisions of this permit are severable, and if any provision of this permit, or application of any provision of this permit to any circumstance, is held invalid, the application of such provision to other circumstances, and the remainder of this permit shall not be affected thereby. G26. BYPASS PROHIBITED A. Bvpass Procedures Bypass, which is the intentional diversion of waste streams from any portion of a treatment facility, is prohibited for stormwater events below the design criteria for stormwater management. Ecology may take enforcement action against a Pc�r��'�:�� t�,�� bypass unless one of the following circumstances (1, 2, 3 or 4) is applicabl� 1. Bypass of stormwater is consistent with the design criteria and part of aii appru��d management practice in the applicable stormwater management manual. 2. Bypass for essential maintenance without the potential to cause violation of permit limits or conditions. Bypass is authorized if it is for essential maintenance and does not have the potential to cause violations of limitations or other conditions of this permit, or adversely impact public health. 3. Bypass of stormwater is unavoidable, unanticipated, and results in noncompliance of this permit. This bypass is permitted only i£ a. Bypass is unavoidable to prevent loss of life, personal injury, or severe property damage. "Severe property damage" means substantial physical damage to property, damage to the treatment facilities which would cause them to become inoperable, or substantial and permanent loss of natural resources��hich can reasonably be expected to occur in the absence of a bypass. b. There are no feasible alternatives to the b;-pass, such as the use of auxiliary treatment facilities, retention of untreated wastes, maintenance during normal periods of equipment downtime (but not if adequate backup equipment should have been installed in the exercise of reasonable engineering judgment to prevent a bypass which occurred during normal periods of equipment downtime or preventative maintenance), or transport of untreated ��astes to another treatment facility. Construction Stormtivater General Pernzrt—Decernbef� 1, 2010 Page 43 c. Ecology is properly notified of the bypass as required in Special Condition SS.F of this permit. 4. A planned action that would cause bypass of stormwater and has the potential to result in noncompliance of this permit during a storm event. The Permittee must notify Ecology at least thirty (30) days before the planned date of bypass. The notice must contain: a. a description of the bypass and its cause b. an analysis of all known alternatives which would eliminate, reduce, or mitigate the need for bypassing. c. a cost-effectiveness analysis of alternatives including comparative resource damage assessment. d. the minimum and m�imum duration of bypass under each alternative. e. a recommendation as to the preferred alternative for conducting the bypass. f. the projected date of bypass initiation. g. a statement of compliance with SEPA. h. a request for modification of water quality standards as provided for in WAC 173-201A-110, if an exceedance of any water quality standard is anticipated. i. steps taken or planned to reduce, eliminate, and prevent reoccurrence of the bypass. 5. For probable construction bypasses, the need to bypass is to be identified as early in the planning process as possible. The analysis required above must be considered during preparation of the Stormwater Pollution Prevention Plan (SWPPP)and must be included to the extent practical. In cases�vhere the probable need to bypass is determined early, continued analysis is necessary up to and including the construction period in an effort to minimize or eliminate the bypass. Ecology will consider the following before issuing an administrative order for this type bypass: a. If the bypass is necessary to perform construction or maintenance-related activities essential to meet the requirements of this permit. b. If there are feasible alternatives to bypass, such as the use of auxiliary treatment facilities, retention of untreated wastes, stopping production, maintenance during normal periods of equipment down time, or transport of untreated wastes to another treatment facility. c. If the bypass is planned and scheduled to minimize adverse effects on the public and the environment. Construction Stormwater General Permit—December 1, 2010 Page 44 After consideration of the above and the adverse effects of the proposed bypass and any other relevant factors, Ecology will approve, conditionally approve, or deny the request. The public must be notified and given an opportuniiy to comment on bypass incidents of significant duration, to the extent feasible. Approval of a request to bypass will be by administrative order issued by Ecology under RCW 90.48.120. B. Duty to Miti a�te The Permittee is required to take all reasonable steps to minimize or prevent any discharge or sludge use or disposal in violation of this permit that has a reasonable likelihood of adversely affecting human health ar the environment. Construction Storrnwater General Per�rsiit—Decef�iber 1, 2010 Page 45 APPENDIX A—DEFINITIONS AKART is an acronym for"all known, available, and reasonable methods of prevention, control, and treatment." AKART represents the most current methodology that can be reasonably required for preventing, controlling, or abating the pollutants and controlling pollution associated with a discharge. Anplicable TMDL means a TMDL for turbidity, fine sediment, high pH, or phosphorus, which was completed and approved by EPA before January 1, 2011, or before the date the operator's complete permit application is received by Ecology, whichever is later. Applicant means an o ep rator seeking coverage under this permit. Best Mana�ement Practices (BMPs)means schedules of activities, prohibitions of practices, maintenance procedures, and other physical, structural and/or managerial practices to prevent or reduce the pollution of waters of the State. BMPs include treatment systems, operating procedures, and practices to control: stormwater associated with construction activity, spillage or leaks, sludge or waste disposal, or drainage from raw material storage. j Buffer means an area designated by a local jurisdiction that is contiguous to and intended to protect a sensitive area. Bvt�ass means the intentional diversion of waste streams from any portion of a treatment facility. Calendar Dav A period of 24 consecutive hours starting at 12:00 midnight and ending the following 12:00 midnight. Calendar Week(same as «�eek) means a period of seven consecutive days starting at 12:01 a.m. (0:01 hours) on Sunday. Certified Erosion and Sediment Control Lead (CESCL) means a person who has current certification through an approved erosion and sediment control training program that meets the minimum training standards established by Ecology (see BMP C160 in the SWMM). Clean Water Act (CWA) means the Federal Water Pollution Control Act enacted by Public La�� 92-500, as amended by Public Laws 95-217, 95-576, 96-483, and 97-117; USC 1251 et seq. Combined Sewer means a sewer��hich has been designed to serve as a sanitary se��er and a storm sewer, and into which inflow is allowed by local ordinance. Common Plan of Development or Sale means a site where multiple separate and distinct construction activities may be taking place at different times on different schedules and/or by different contractors, but still under a single plan. Examples include: 1) phased projects and projects with multiple filings or lots, even if the separate phases or filings/lots will be constructed under separate contract or by separate owners (e.g., a development where lots are sold to separate builders); 2) a development plan that maST be phased o��er multiple years, but is still under a Constf•uction Stormtivuter General Pef•nTit—Decenzber� 1, 2010 Page 46 consistent plan for long-term development; 3) projects in a contiguous area that may be unrelated but still under the same contract, such as construction of a building extension and a new parking lot at the same facility; and 4) linear projects such as roads, pipelines, or utilities. If the project is part of a common plan of development or sale,the disturbed area of the entire plan must be used in determining permit requirements. Composite Sample means a mixture of grab samples collected at the same sampling point at different times, formed either by continuous sampling or by mixing discrete samples. May be "time-composite" (collected at constant time intervals) ar "flow-proportional" (collected either as a constant sample volume at time intervals proportional to stream flow, or collected by increasing the volume of each aliquot as the flow increases while maintaining a constant time interval between the aliquots. Concrete wastewater means any water used in the production, pouring and/or clean-up of concrete or concrete products, and any water used to cut, grind, wash, or otherwise modify concrete or concrete products. Examples include water used for or resulting from concrete truck/mixer/pumper/tooUchute rinsing or washing, concrete saw cutting and surfacing (sawing, caring, grinding, roughening, hydro-demolition, bridge and road surfacing). When stormwater comingles with concrete wastewater,the resulting water is considered concrete wastewater and must be managed to prevent discharge to waters of the state, including ground water. Construction Activitv means land disturbing operations including clearing, grading ar excavation which disturbs the surface of the land. Such activities may include road construction, construction of residential houses, office buildings, ar industrial buildings, and demolition j activity. Contaminant means any hazardous substance that does not occur naturally or occurs at greater than natural background levels. See definition of"hazardous substance" and WAC 173-340-200. Demonstrablv Equivalent means that the technical basis for the selection of all stormwater BMPs is documented within a SWPPP, including: 1. The method and reasons for choosing the stormwater BMPs selected. 2. The pollutant removal performance expected from the BMPs selected. 3. The technical basis supporting the performance claims for the BMPs selected, including any available data concerning field performance of the BMPs selected. 4. An assessment of how the selected BMPs will comply with state water quality standards. 5. An assessment of how the selected BMPs will satisfy both applicable federal technology- based treatment requirements and state requirements to use all known, available, and reasonable methods of prevention, control, and treatment (AKART). Department means the Washington State Department of Ecology. Detention means the temporary storage of stormwater to improve quality and/or to reduce the mass flow rate of discharge. Construction Stormivater General Perrnit—Decesfiber 1, 2010 Page 47 Dewaterin�means the act of pumping ground water or stormwater away from an active construction site. Director means the Director of the Washington Department of Ecology or his/her authorized representative. Discharger means an owner or operator of any facility or activity subject to regulation under Chapter 90.48 RCW or the Federal Clean Water Act. Domestic Wastewater means water carrying human wastes, including kitchen, bath, and laundry �vastes from residences, buildings, industrial establishments, or other places, together with such ground water infiltration or surface waters as may be present. Ecolo�v means the Washington State Department of Ecology. En�ineered Soils means the use of soil amendments including, but not limited, to Portland cement treated base (CTB), cement kiln dust(CKD), or fly ash to achieve certain desirable soil characteristics. Eauivalent BMPs means operational, source control, treatment, or innovative BMPs which result in equal or better quality of stormwater discharge to surface«�ater or to ground water than BMPs selected from the SWMM. Erosion means the wearing away of the land surface by running water, wind, ice, or other geological agents, including such processes as gravitational creep. Erosion and Sediment Control BMPs means BMPs intended to prevent erosion and sedimentation, such as preserving natural vegetation, seeding, mulching and matting,plastic covering, filter fences, sediment traps, and ponds. Erosion and sediment control BMPs are synonymous with stabilization and structural BMPs. Final Stabilization (same as fully stabilized or full stabilization) means the establishment of a permanent vegetative cover, or equivalent permanent stabilization measures (such as riprap, gabions or geotextiles)which prevents erosion. Ground Water means water in a saturated zone or stratum beneath the land surface or a surface water body. Hazardous Substance means any dangerous or extremely hazardous waste as defined in RCW 70.105.010 (5) and (6), or any dangerous or extremely dangerous waste as designated by rule I under chapter 70.105 RCW; any hazardous sub-stance as defined in RCW 70.105.010(14) or any hazardous substance as defined by rule under chapter 70.105 RCW; any substance that, on the effective date of this section, is a hazardous substance under section 101(14) of the federal cleanup law, 42 U.S.C., Sec. 9601(14); petroleum or petroleum products; and any substance or category of substances, including solid waste decomposition products, determined by the director I Construction Stormwater General Permit—December 1, 2010 ', Page 48 by rule to present a threat to human health or the environment if released into the environment. The term hazardous substance does not include any of the following when contained in an underground storage tank from which there is not a release: crude oil or any fraction thereof or petroleum, if the tank is in compliance with all applicable federal, state, and local law. Iniection Well means a well that is used for the subsurface emplacement of fluids. (See Well.) Jurisdiction means a political unit such as a city,town or county; incorporated for local self- government. National Pollutant Dischar�e Elimination Svstem (NPDES) means the national program for issuing, modifying, revoking and reissuing, terminating, monitoring, and enforcing permits, and imposing and enforcing pretreatment requirements, under sections 307, 402, 318, and 405 of the Federal Clean Water Act, for the discharge of pollutants to surface waters of the State from point sources. These permits are referred to as NPDES permits and, in Washington State, are administered by the Washington Department of Ecology. Notice of Intent (NOI) means the application for, or a request for coverage under this general permit pursuant to WAC 173-226-200. Notice of Termination(NOT)means a request for termination of coverage under this general permit as specified by Special Condition S 10 of this permit. Operator means any party associated with a construction project that meets either of the following two criteria: • The party has operational control over construction plans and specifications, including the ability to make modifications to those plans and specifications; or • The party has day-to-day operational control of those activities at a project that are necessary to ensure compliance with a SWPPP for the site or other permit conditions (e.g., they are authorized to direct workers at a site to carry out activities required by the S WPPP or comply with other permit conditions). Permittee means individual or entity that receives notice of coverage under this general permit. �H means a liquid's measure of acidity or alkalinity. A pH of 7 is defined as neutral. Large variations above or below this value are considered harmful to most aquatic life. pH monitorin�period means the time period in which the pH of stormwater runoff from a site must be tested a minimum of once every seven days to determine if stormwater pH is between 6.5 and 8.5. '� � Point source means any discernible, confined, and discrete conveyance, including but not limited to, any pipe, ditch, channel, tunnel, conduit, well, discrete fissure, and container from which pollutants are or may be discharged to surface waters of the State. This term does not include return flows from irrigated agriculture. (See Fact Sheet for further explanation.) Construction Stormwater General Permit—December 1, 2010 Page 49 Pollutant means dredged spoil, solid waste, incinerator residue, filter backwash, sewage, garbage, domestic sewage sludge (biosolids), munitions, chemical wastes, biological materials, radioactive materials, heat, wrecked or discarded equipment, rock, sand, cellar dirt, and industrial, municipal, and agricultural waste. This term does not include sewage from vessels within the meaning of section 312 of the CWA, nor does it include dredged or fill material discharged in accordance with a permit issued under section 404 of the CWA. Pollution means contamination or other alteration of the physical, chemical, or biological properties of waters of the State; including change in temperature, taste, color, turbidity, or odor of the waters; or such discharge of any liquid, gaseous, solid, radioactive or other substance into any waters of the State as will or is likely to create a nuisance or render such waters harmful, detrimental or injurious to the public health, safety ar v�Telfare; or to domestic, commercial, industrial, agricultural, recreational, or other legitimate beneficial uses; or to livestock, wild animals, birds, fish or other aquatic life. Process wastewater means any water which, during manufacturing or processing, comes into direct contact with ar results from the production or use of any raw material, intermediate product, finished product, byproduct, or waste product (40 CFR 122.1). Receiving water means the water body at the point of discharge. If the discharge is to a storm sewer system, either surface or subsurface,the receiving water is the water body to which the storm system discharges. Systems designed primarily for other purposes such as for ground water drainage, redirecting stream natural flows, or for conveyance of irrigation water/return '� flows that coincidentally convey stormwater are considered the receiving water. Representative means a stormwater or wastewater sample which represents the flow and characteristics of the discharge. Representative samples may be a grab sample, a time- proportionate composite sample, or a flow proportionate sample. Ecology's Construction Stormwater Monitoring Manual provides guidance on representative sampling. Sanitarv sewer means a sewer which is designed to convey domestic wastewater. Sediment means the fragmented material that originates from the weathering and erosion of rocks or unconsolidated deposits, and is transported by, suspended in, or deposited by water. Sedimentation means the depositing or formation of sediment. Sensitive area means a ��-ater body, «-etland, stream, aquifer recharge ai•ea, or channel migration zone. SEPA (State Environmental Policy Act) means the Washington State La��-, RCW 43.21C.020, intended to prevent or eliminate damage to the environment. Si�nificant Amount means an amount of a pollutant in a discharge that is amenable to available and reasonable methods of prevention or treatment; or an amount of a pollutant that has a Construction Stormla�ater General Per•rnit—Decernbef- 1, 2010 Page 50 reasonable potential to cause a violation of surface or ground water quality or sediment management standards. Significant concrete work means greater than 1000 cubic yards poured concrete or recycled concrete over the life of a project. Si�nificant Contributor of Pollutants means a facility determined by Ecology to be a contributor of a significant amount(s) of a pollutant(s)to waters of the State of Washington. Site means the land or water area where any "facility or activity" is physically located or conducted. Source control BMPs means physical, structural or mechanical devices or facilities that are intended to prevent pollutants from entering stormwater. A few examples of source control BMPs are erosion control practices,maintenance of stormwater facilities, constructing roofs over storage and working areas, and directing wash water and similar discharges to the sanitary se�ver or a dead end sump. �"'. Stabilization means the application of appropriate BMPs to prevent the erosion of soils, such as, temporary and permanent seeding, vegetative covers, mulching and matting, plastic covering and sodding. See also the definition of Erosion and Sediment Control BMPs. Storm drain means any drain which drains directly into a storm sewer svstem, usually found , along roadways or in parking lots. Storm sewer s, s�means a means a conveyance, or system of conveyances (including roads ��vith drainage systems, municipal streets, catch basins, curbs, gutters, ditches, manmade channels, or storm drains designed or used for collecting or conveying stormwater. This does �- not include systems which are part of a combined sewer or Publicly O�vned Treatment Works (POTW) as defined at 40 CFR 122.2. Stormv�7ater means that portion of precipitation that does not naturally percolate into the ground or evaporate, but flows via overland flow, interflow, pipes, and other features of a stormwater drainage system into a defined surface water body, or a constructed infiltration facilit}�. Stormwater Management Manual (SWMM) or Manual means the technical Manual published by Ecology for use by local governments that contain descriptions of and design criteria for BMPs to prevent, control, or treat pollutants in stormwater. Stormwater Pollution Prevention Plan�WPPP� means a documented plan to implement measures to identify, prevent, and control the contamination of point source discharges of stormwater. Surface Waters of the State includes lakes, rivers,ponds, streams, inland«�aters, salt ��aters, and all other surface waters and«ater courses ��ithin the jtu�isdiction of the state of��ashington. Construction Stormwater General Per•mit—Decefnber 1, 201 D Page 51 Temporarv Stabilization means the exposed ground surface has been covered with appropriate materials to provide temporary stabilization of the surface from water or wind erosion. Materials include, but are not limited to, mulch, riprap, erosion control mats or blankets and temporary cover crops. Seeding alone is not considered stabilization. Temporary stabilization is not a substitute for the more permanent"final stabilization." Total Maximum Dailv Load(TMDL)means a calculation of the maximum amount of a pollutant that a�vater body can receive and still meet state water quality standards. Percentages of the total maximum daily load are allocated to the various pollutant sources. A TMDL is the sum of the allowable loads of a single pollutant from all contributing point and nonpoint sources. The TMDL calculations must include a "margin of safety" to ensure that the water body can be protected in case there are unforeseen events or unknown sources of the pollutant. The calculation must also account for seasonable variation in water quality. Treatment BMPs means BMPs that are intended to remove pollutants from stormwater. A fe�v examples of treatment BMPs are detention ponds, oil/water separators, biofiltration, and constructed wetlands. Transparencv means a measurement of��ater clarity in centimeters (cm), using a 60 cm transparency tube. The transparency tube is used to estimate the relative clarity or transparency of water by noting the depth at which a black and white Secchi disc becomes visible when water is released from a value in the bottom of the tube. A transparency tube is sometimes referred to as a "turbidity tube." Turbidi means the clarity of water expressed as nephelometric turbidity units (NTU}and , measured with a calibrated turbidimeter. Uncontaminated means free from any contaminant, as defined in MTCA cleanup regulations. See definition of"contaminant" and WAC 173-340-200. Waste Load Allocation(��LA) means the portion of a receiving water's loading capacity that is allocated to one of its existing or future point sources of pollution. WLAs constitute a type of water quality based effluent limitation (40 CFR 130.2[h]). Water qualitv means the chemical,physical, and biological characteristics of water, usually with respect to its suitability for a particular purpose. Waters of the State includes those waters as defined as "��aters of the United States" in 40 CFR Subpart 122.2 within the geographic boundaries of Washington State and "waters of the State" as defined in Chapter 90.48 RCW, which include lakes, rivers,ponds, streams, inland waters, underground waters, salt waters, and all other surface waters and water courses within the jurisdiction of the state of Washington. Well means a bored, drilled or driven shaft, or dug hole whose depth is greater than the largest surface dimension. (See Injection well.) Construction Storrnwatef•General Permit—December 1, 2010 Page 52 Wheel wash wastewater means any water used in, or resulting from the operation of, a tire bath or wheel wash (BMP C106: Wheel Wash), or other structure or practice that uses water to physically remove mud and debris from vehicles leaving a construction site and prevent track- out onto roads. When stormwater comingles with wheel wash wastewater, the resulting water is considered wheel wash waste��ater and must be managed according to Special Condition S9.D.9. Constrasction Stormwater General Permit—December 1, 2010 Page 53 APPENDIX B—ACRONYMS AKART All Known, Available,and Reasonable Methods of Prevention, Control, and Treatment BMP Best Management Practice CESCL Certified Erosion and Sediment Control Lead CFR Code of Federal Regulations CKD Cement Kiln Dust cm Centimeters CTB Cement-Treated Base CWA Clean Water Act DMR Discharge Monitoring Report EPA Environmental Protection Agency ESC Erosion and Sediment Control FR Federal Register NOI Notice of Intent NOT Notice of Termination NPDES National Pollutant Discharge Elimination System NTU Nephelometric Turbidity Unit RCW Revised Code of Washington SEPA State Environmental Policy Act SWMM Stormwater Management Manual SWPPP Stormwater Pollution Prevention Plan TMDL Total Maximum Daily Load UIC Underground Injection Control USC United States Code USEPA United States Environmental Protection Agency WAC Washington Administrative Code WQ Water Quality WWHM Western Washington Hydrology Model Construction Stormwater General Per•rnit— Decembef• 1, 2010 Page 54 APPENDIX E - SITE INSPECTION FORMS (AND SITE LOG) The results of each inspection shall be summarized in an inspection report or checklist that is entered into or attached to the site log book. It is suggested that the inspection report or checklist be included in this appendix to keep monitoring and inspection information in one document, but this is optional. However, it is mandatory that this SWPPP and the site inspection forms be kept onsite at all times during construction, and that inspections be performed and documented as outlined below. At a minimum, each inspection report or checklist shall include: a. Inspection date/times b. Weather information: general conditions during inspection, approximate amount of precipitation since the last inspection, and approximate amount of precipitation within the last 24 hours. c. A summary or list of all BMPs that have been implemented, including observations of all erosion/sediment control structures or practices. d. The following shall be noted: i. locations of BMPs inspected, ii. locations of BMPs that need maintenance, iii. the reason maintenance is needed, iv. locations of BMPs that failed to operate as designed or intended, and v. locations where additional or different BMPs are needed, and the reason(s) why e. A description of stormwater discharged from the site. The presence of suspended sediment, turbid water, discoloration, and/or oil sheen shall be noted, as applicable. f. A description of any water quality monitoring performed during inspection, and the results of that monitoring. g. General comments and notes, including a brief description of any BMP repairs, maintenance or installations made as a result of the inspection. h. A statement that, in the judgment of the person conducting the site inspection, the site is either in compliance or out of compliance with the terms and conditions of the SWPPP and the NPDES permit. If the site inspection indicates that the site is out of compliance, the inspection report shall include a summary of the remedial actions required to bring the site back into compliance, as well as a schedule of implementation. i. Name, title, and signature of person conducting the site inspection; and the following statement: "I certify under penalty of law that this report is true, accurate, and complete, to the best of my knowledge and belief". O 2015 D.R.STRONG Consulting Engineers Inc. Page 26 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 When the site inspection indicates that the site is not in compliance with any terms and conditions of the NPDES permit, the Permittee shall take immediate action(s) to: stop, contain, and clean up the unauthorized discharges, or otherwise stop the noncompliance; correct the problem(s); implement appropriate Best Management Practices (BMPs), and/or conduct maintenance of existing BMPs; and achieve compliance with all applicable standards and permit conditions. In addition, if the noncompliance causes a threat to human health or the environment, the Permittee shall comply with the Noncompliance Notification requirements in Special Condition SS.F of the permit. rJ 2015 D. R.STRONG Consulting Engineers Inc. Page 27 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 SITE INSPECTION FORM General Information Project Name: Inspector Name: Title: CESCL# : Date: Time: Inspection Type: ❑ After a rain event ❑ Weekly ❑ Turbidity/transparency benchmark exceedance ❑ Other Weather Precipitation Since last inspection In last 24 hours Description of General Site Conditions: � Inspection of BMPs Element 1: Mark Clearing Lirr BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action Element 2: Establish Construction Access BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action Element 3: Control Flow Rates BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP O 2015 D. R.STRONG Consulting Engineers Inc. Page 28 of 44 Stormwater Pollution Pre�ention Plan The Enclave at Bridle Ridge June 23,2014 BMP: Inspected Functioning Location Y N Y N N I P Problem/Corrective Action Element 4: lnstall Sediment Controls BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action Element 5: Stabilize Soils BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action O 2015 D.R.STRONG Consulting Engineers Inc. Page 29 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 � BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action E/ement 6: Protect Slopes BMP: inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action Element 7: Protect Drain Inlets BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action O 2015 D.R.STRONG Consufting Engineers Inc. Page 30 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 �- - � � Elemenr 8: Stabilize Channels and Outlefs BMP: Location Inspected Functioning ProblemlCorrective Action Y N Y N NIP BMP: Inspected Functioning Location Y N Y N NIP ProblemlCorrective Action BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BM P: Inspected Functioning Location Y N Y N NIP Probiem/Corrective Action Element 9: Control Pollutants BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action Element 10: Control Dewatering BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP �J 2015 D.R.STRONG Consulting Engineers Inc. Page 31 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 i +� �, �`- .. . _ . . , ... . ''� BMP: Inspected Functioning Location Y N Y N NIP Problem/Corrective Action Stormwater Discharges From the Site Observed? Problem/Corrective Action Y ON Location Turbidity Discoloration Sheen Location Turbidity Discoloration Sheen Water Quality Monitoring Was any water quality monitoring conducted? ❑ Yes ❑ No If water quality monitoring was conducted, record results here: If water quality monitoring indicated turbidity 250 NTU or greater; or transparency 6 cm or less, was Ecology notified by phone within 24 hrs? ❑ Yes ❑ No If Ecology was notified, indicate the date, time, contact name and phone number below: Date: Time: Contact Name: Phone#: General Comments and Notes Include BMP repairs, maintenance, or installations made as a result of the inspection. Were Photos Taken? ❑ Yes ❑ No If photos taken, describe photos below: O 2015 D.R.STRONG Consulting Engineers Inc. Page 32 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 ' ! x-. ,�•,� ..� . . . .r � _ . . � . .i ,y�.` - . � . � � *�. + - t 6-�• . . . . � � � _. . : . . .. ,. .. . � . APPENDIX F - ENGINEERING CALCULATIONS C�2015 D. R.STRONG Consulting Engineers Inc. Page 33 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 1 -,� � EXISTING SITE HYDROLOGY For the purpose of these calculations the predeveloped site conditions were modeled as ' "till forest". � Modeling input , Land cover Entire I S ite ', Till forest (ac) 8.973 � Till Grass (ac) 0.000 Wetland (ac) 0.000 Impervious (ac) 0.000 Scale Factor: 1.00 Time Step: Hourly Data Type: Reduced Project location: Seatac Total Area: 8.973 Table 1 Pre-Developed KCRTS Modeling Input Modeling results Entire Site F�ow Frequency :'.na-_,�sis Time Series File:predev.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----rlow Frequency P_nalysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS} Period 0.566 2 2/09/O1 18:00 0.724 1 100.00 0.990 0.154 7 1/06/02 3:00 0.566 2 25.00 0.9E0 0.419 4 2/28/03 3:00 0.435 3 10.00 0.900 0.015 8 3/24/04 20:00 0.419 4 5.00 0.8C� 0.249 6 1/05/05 8:00 0.366 5 3.00 0.60, 0.935 3 1/18/06 21:00 0.249 6 2.00 0.5Q0 0.366 5 11/24/06 4:00 0.154 7 1.30 0.231 0.724 1 1/09/08 9:00 0.015 8 1.10 0.091 Computed ?ea'.{s 0. 671 �O.CO 0.°80 �2015 D. R.STRONG ConsuRing Engineers Inc. Page 34 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 , � . � � DEVELOPED SITE HYDROLOGY Soil type The soil types are unchanged from pre-developed conditions. Land covers KCRTS was used to model the developed peak runoff from the Site. The portions of the Site within the proposed clearing limits tributary to the proposed detention pond were modeled as "Till Grass" and Impervious as appropriate. Results of the KCRTS analysis are included in this section. Modeling input �Land cover Entire Site Till forest(ac) 0.000 Till Grass(ac) 4.141 Wetland (ac) 0.000 Impervious (ac) 4.765 Scale Factor: 1.00 Time Step: Hourly Data Type: Reduced Project location: Seatac Total Area: 8.906 Table 2 Developed KCRTS Modeling Input Modeling Results Entire Site �'-ow Frequency Analysis Time Series File:rdin.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Ana,_psis -- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prcb (CFS) (CFS) Period 1.52 6 2/09/O1 2:00 3.13 1 100.00 0.990 1.21 8 1/05/02 16:00 1.84 2 25.00 0.96G 1.84 2 2/27/03 7:00 1.84 3 10.00 0.900 1.26 7 8/26/04 2:00 1.62 4 5.00 0.800 1.53 5 10/28/04 16:00 1.53 5 3.00 0.667 1.62 4 1/18/06 16:00 1.52 6 2.00 0.50C 1.84 3 10/26/06 0:00 1.26 7 1.30 0.231 3.13 1 1/09/CS 6:00 1.21 8 1.10 0.091 Comn��,:ted P�aks 2.�0 5�.0� 0.9�0 O 2015 D. R.STRONG Consulting Engineers Inc. Page 35 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 BYPASS AREA HYDROLOGY Modeling Input Land cover Entire Site Till forest(ac) 0.000 Till Grass(ac) 0.025 Wetland (ac) 0.000 Impervious(ac) 0.042 Scale Factor: 1.00 Time Step: Hourly Data Type: Reduced Project location: Seatac Total Area: 0.067 Table 3 Bypass KCRTS Modeling Input Modeling Results Bypass Flow Frequency Analysis Time Series File:bypass.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- I Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.012 6 2/09/O1 2:00 0.025 1 100.00 0.990 0.010 8 1/05/02 16:00 0.016 2 25.00 0.960 0.015 3 2/27/03 7:00 0.015 3 10.00 0.900 0.011 7 8/26/04 2:00 0.013 4 5.00 0.800 0.013 4 10/28/04 16:00 0.013 5 3.00 0.667 0.013 5 1/18/06 16:00 0.012 6 2.00 0.5C0 0.016 2 10/26/06 0:00 0.011 7 1.30 0.231 0.025 1 1/09/08 6:00 0.010 8 1.10 0.091 ' Computed Peaks 0.022 50.00 0.980 0.055 50.00 0.980 The on-site bypass areas satisfy all the requirements set forth in the Manual, Section 1.2. Runoff from the bypass areas and the flow control facilities converge within a quarter-mile. The flow control facility is designed to compensate for uncontrolled bypass. The 100-year discharge from the bypass areas is 0.025 cfs, which is less than the 0.4 cfs threshold. There should be no adverse downstream impacts to the downstream drainage system created by the runoff from the bypass. O 2015 D. R.STRONG Consulting Engineers Inc. Page 36 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 FLOW CONTROL SYSTEM The Project will utilize a detention pond meeting the Level Three Flow Control criteria. This King County KCRTS software was used to size the detention facilities. Flow Control Facility Design Output Retention/Detention Facility Type of Facility: Detention Pond Side Slope: 2.35 H:1V Pond Bottom Length: 160.25 ft Pond Bottom Width: 80.00 ft Pond Bottom Area: 12820. sq. ft Top Area at 1 ft. FB: 21794. sq. ft 0.500 acres Effective Storage Depth: 6.00 ft Stage 0 Elevation: 371.00 ft Storage Volume: 98806. cu. ft 2.268 ac-ft Riser Head: 6.00 ft Riser Diameter: 18.00 inches Number of orifices: 3 Full Head Pipe Orifice # Height Diameter Discharge Diameter (ft) (in) (CFS� (in) 1 0. 00 1.52 0.153 2 3. 80 2.28 0.209 6.0 3 3. 98 2.35 0.213 6.0 Top Notch Weir: None , � Outflow Rating Curve: None '� Stage Elevation Storage Discharge Percolation Surf Area (ft) (ft) (cu. ft) (ac-ft) (cfs) {cfs) (sq. ft) 0.00 371.00 0. 0.000 0.000 0.00 12820. 0.02 371.02 257. 0.006 0.008 0.00 12843. 0.03 371.03 385. 0.009 0.011 0.00 12854. 0.05 371.05 642. 0.015 0.014 0.00 12876. 0.06 371.06 771. 0.018 0.016 0.00 12888. 0.08 371.08 1029. 0.024 0.018 0.00 12910. 0.10 371.10 1288. 0.030 0.019 0.00 12933. 0.11 371.11 1417. 0.033 0.021 0.00 12944. 0.13 371.13 1676. 0.038 0.022 0.00 12967. 0.24 371.24 3109. 0.071 0.031 0.00 13092. 0.36 371.36 4689. 0.108 0.038 0.00 13229. 0.48 371.48 6284. 0.144 0.043 0.00 13366. 0.60 371.60 7897. 0.181 0.048 0.00 13505. 0.71 371.71 9389. 0.216 0.053 0.00 13632. 0.83 371.83 11033. 0.253 0.057 0.00 13771. 0.95 371.95 12694. 0.291 0.061 0.00 13911. 1.07 372.07 14372. 0.330 0.065 0.00 14052. 1.19 372.19 16067. 0.369 0.068 0.00 14193. 1.30 372.30 17635. 0.405 0.072 0.00 14323. 1.42 372_42 19362. 0.444 0.075 0.00 14466. 1.54 372.54 21107. 0.485 0.078 0.00 14609. 1.66 372.66 22869. 0.525 0.081 0.00 14753. 1.77 372.77 24499. 0.562 0.083 0.00 14885. 1.89 372.89 26294. 0.604 0.086 0.00 15030. O 2015 D. R.STRONG Consulting Engineers Inc. Page 37 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 �= `�, 2.01 373.01 28106. 0.645 0.089 0.00 15176. 2.13 373.13 29936. 0.687 0.091 0.00 15322. 2.24 373.24 31629. 0.726 0.094 0.00 15457. 2.36 373.36 33492. 0.769 0.096 0.00 15604. 2.48 373.48 35374. 0.812 0.099 0.00 15752. 2.60 373.60 37273. 0.856 0.101 0.00 15901. 2.71 373.71 39029. 0.896 0.103 0.00 16038. 2.83 373.83 40963. 0.940 0.105 0.00 16188. 2.95 373.95 42915. 0.985 0.108 0.00 16339. 3.07 374.07 44884. 1.030 0.110 0.00 16490. 3.19 374.19 46872. 1.076 0.112 0.00 16642. 3.30 374.30 48710. 1.118 0.114 0.00 16781. 3.42 374.42 50733. 1.165 0.116 0.00 16935. 3.54 374.54 52775. 1.212 0.118 0.00 17088. 3.66 374.66 54835. 1.259 0.120 0.00 17243. 3.77 374.77 56739. 1.303 0.122 0. 00 17385. 3.80 374.80 57261. 1.315 0.122 0.00 17424. 3.82 374.82 57610. 1.323 0.124 0.00 17449. 3.85 374.85 58134. 1.335 0.128 0.00 17488. 3.87 374.87 58484. 1.343 0.135 0.00 17514. 3.90 374.90 59010. 1.355 0.145 0.00 17553. 3.92 374.92 59361. 1.363 0.157 0.00 17579. 3.94 374.94 59713. 1.371 0.171 0.00 17605. 3.97 374.97 602�2. 1.383 0.182 0.00 17644. 3.98 374.98 60419. 1.387 0.185 0.00 17657. 4.00 375.00 60772. 1.395 0.191 0.00 17683. 4.03 375.03 61303. 1.407 0.199 0.00 17723. 4.05 375.05 61658. 1.415 0.210 0.00 17749. 4.08 375.08 62191. 1.428 0.223 0.00 17788. 4.10 375.10 62547. 1.436 0.239 0.00 17814. 4.13 375.13 63082. 1.448 0.257 0.00 17853. , 4.15 375.15 63439. 1.456 0.273 0.00 17880. 4.18 375.18 63976. 1.469 0.281 0.00 17919. 4.29 375.29 65955. 1.514 0.313 0.00 18063. 4.41 375.41 68132. 1.564 0.340 0.00 18222. 4.53 375.53 70328. 1.615 0.365 0.00 18381. 4.65 375.65 72544. 1.665 0.387 0.00 18540. 4.76 375.76 74591. 1.712 0.408 0.00 18687. 4.88 375.88 76843. 1.764 0.427 0.00 18848. 5.00 376.00 79115. 1.816 0.446 0.00 19010. 5.12 376.12 81406. 1.869 0.463 0.00 19172. 5.23 376.23 83523. 1.917 0.480 0.00 19321. 5.35 376.35 85851. 1.971 0.496 0.00 19484. 5.47 376.47 88199. 2.025 0.512 0.00 19648. 5.59 376.59 90566. 2.079 0.527 0.00 19813. 5.71 376.71 92954. 2.134 0.541 0.00 19978. 5.82 376.82 95160. 2.185 0.555 0.00 20130. 5.99 376.94 97585. 2.240 0.569 0.00 20296. 6.00 377.00 98806. 2.268 0.576 0.00 20380. 6.10 377.10 100851. 2.315 1.050 0.00 20519. 6.20 377.20 102909. 2.362 1.900 0.00 20659. 6.30 377.30 104982. 2.410 3.010 0.00 20799. 6.40 377.40 107069. 2.458 4.310 0.00 20940. 6.50 377.50 109170. 2.506 5.790 0.00 21081. 6.60 377.60 111286. 2.555 7.230 0.00 21223. 6_70 377.70 113415. 2.604 7.770 0.00 21365. 6.80 377.80 115559. 2.653 8.270 0.00 21507. 6.90 377.90 117716. 2.702 8.740 0.00 21650. 7.00 378.00 119889. 2.752 9.190 0.00 21794. 7.10 378.10 122075. 2.802 9.610 0.00 21938. O 2015 D. R.STRONG Consulting Engineers Inc. Page 38 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 7.20 378.20 124276. 2.853 10.020 0.00 22082. 7.30 376.30 126492. 2.904 10.410 0.00 22227. 7.40 378.40 128722. 2.955 10.780 0.00 22372. 7.50 378.50 130966. 3.007 11.150 0.00 22517. 7.60 378.60 133225. 3.058 11.500 0.00 22663. 7.70 378.70 135499. 3.111 11.840 0.00 22810. 7.80 378.80 137787. 3.163 12.170 0.00 22957. 7.90 378.90 140090. 3.216 12.490 0.00 23104. 8.00 379.00 142408. 3.269 12.800 0.00 23252. Hyd Inflow Outflow Peak Storage Stage Elev (Cu-Ft) (Ac-Ft) 1 3.00 0.72 6.03 377. 03 99419. 2 .282 2 1.45 0.51 5. 48 376.48 88399. 2 .029 3 1.75 0.42 4 .86 375.86 76441. 1.755 4 1. 67 0.42 4. 82 375.82 75753. 1 .739 5 1.53 0.28 4.19 375. 19 64191. 1 .474 6 1.40 0. 15 3. 91 374. 91 59120. 1.357 7 1. 12 0.11 3.31 374. 31 48933. 1.123 8 1.15 0. 09 2.10 373. 10 29455. 0.676 Hyd R/D Facility Tributary Reservoir POC Outflow Outflow Inflow Inflow Target Calc 1 0.72 0. 02 ******** 0.72 0.72 2 0.51 0.01 ******** ******* 0.52 3 0. 42 0.01 ******** ******* 0.43 4 0.42 0.02 ******** ******* 0.42 5 0.28 0.01 ******** ******* 0.29 6 0. 15 0.01 ******** ******* 0. 15 7 0. 11 0.01 ******** ******* 0. 12 8 0.09 0.01 ******** ******* 0.09 Route Time Series through Facility Inflow Time Series File:rdin.tsf Outflow Time Series File:rdout POC Time Series File:dsout ?nflow/Outflow Analysis Peak Inflow Discharge: 3.00 CFS at 6:00 on Jan 9 in Year 8 Peak Outflow Discharge: 0.718 CFS at 11: 00 on Jan 9 in Year 8 Peak Reservoir Stage: 6. 03 Ft Peak Reservoir Elev: 377. 03 Ft ' Peak Reservoir Storage: 99419. Cu-Ft . 2 .282 Ac-Ft Add Time Series:bypass.tsf Peak Summed Discharge: 0.724 CFS at 11:00 on Jan 9 in Year 8 Point of Compliance File:dsout.tsf Flow Frequency Analysis Time Series File:rdout.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob O 2015 D. R.STRONG Consulting Engineers Inc. Page 39 of 44 Stormwater Poilution Prevention Plan The Enclave at Bridle Ridge June 23,2014 t: } �� . � (CFS) (CFS) (ft) Period 0.513 2 2/09/Ol 20:00 0.718 6.03 1 100.00 0. 990 0. 114 7 1/07/02 5:00 0.513 5.48 2 25.00 0. 960 0.424 3 3/06/03 22:00 0.424 4.86 3 10.00 0 . 900 0.090 8 8/26/04 8:00 0.418 4.82 4 5.00 0.800 0.149 6 1/08/05 3:00 0.284 4. 19 5 3.00 0. 667 0.284 5 1/19/06 1: 00 0. 149 3. 91 6 2.00 0.500 0.418 4 11/24/06 8:00 0.114 3. 31 7 1.30 0.231 0.718 1 1/09/08 11:00 0. 090 2. 10 8 1. 10 0. 091 Computed Peaks 0. 650 6.02 50.00 0. 980 Flow Frequency Analysis Time Series File:dsout.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob {CFS) (CFS) Period 0.517 2 2/09/Ol 20:00 0.724 1 100.00 0. 990 0. 115 7 1/07/02 2:00 0.517 2 25. 00 0 . 960 0. 426 3 3/06/03 22:00 0.426 3 10. 00 0. 900 0.092 8 8/26/04 2:00 0.421 4 5. 00 0.800 0. 150 6 1/08/05 3:00 0.286 5 3.00 0. 667 0.286 5 1/19/06 1:00 0. 150 6 2.00 0.500 0.421 4 11/24/06 8:00 0. 115 7 1.30 0.231 0.724 1 1/09/08 11:00 0.092 8 1. 10 0.091 Computed Peaks 0. 655 50.00 0 . 980 Flow Duration from Time Series File:rdout.tsf Cutoff Count Frequency CDF Exceedence Probability CFS ° ° ° - 0 0 0 0.007 33321 54.340 54.340 45.660 0. 457E+00 0.022 5984 9.759 64.098 35. 902 0.359E+00 0.036 5280 8. 611 72.709 27.291 0.273E+00 0.051 4910 8.007 80.716 19.284 0. 193E+00 0. 065 4127 6.730 87 .446 12 .554 0. 126E+00 0.079 2989 4.874 92 . 321 7. 679 0.768E-01 0.094 1762 2.873 95. 194 4.806 0. 481E-01 0. 108 1335 2.177 97.371 2.629 0.263E-01 0. 123 1183 1.929 99.300 0.700 0.700E-02 0.137 72 0.117 99. 418 0.582 0.582E-02 0. 152 42 0.068 99. 486 0.514 0.514E-02 0. 166 24 0.039 99.525 0.475 0.475E-02 0. 180 25 0.041 99.566 0.434 0. 434E-02 0. 195 36 0.059 99. 625 0.375 0.375E-02 0.209 16 0.026 99. 651 0.349 0.349E-02 0.224 18 0.029 99. 680 0.320 0.320E-02 0.238 9 0.015 99. 695 0.305 0.305E-02 0.253 17 0.028 99.723 0.277 0.277E-02 0.267 10 0.016 99.739 0.261 0.261E-02 0.281 13 0.021 99.760 0.240 0.240E-02 0.296 22 0.036 99.796 0.204 0.204E-02 0.310 12 0.020 99.816 0.184 0. 184E-02 0.325 13 0.021 99.837 0.163 0. 163E-02 0.339 10 0.016 99.853 0. 147 0. 147E-02 O 2015 D.R.STRONG Consulting Engineers Inc. Page 40 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 -. ; -:p>- .•a- Y� 0.354 12 0.020 99.873 0.127 0. 127E-02 0.368 7 0.011 99.884 0.116 0. 116E-02 0.382 9 0.015 99.899 0.101 O. 101E-02 0. 397 7 0.011 99. 910 0.090 0.897E-03 0. 411 9 0.015 99. 925 0.075 0.750E-03 0. 426 15 0.024 99. 949 0.051 0.506E-03 0.440 9 0.015 99. 964 0.036 0.359E-03 0.455 4 0.007 99. 971 0.029 0.294E-03 0.469 3 0.005 99.976 0.024 0.245E-03 0.483 4 0.007 99. 982 0.018 0. 179E-03 0.498 4 0.007 99. 989 0.011 0. 114E-03 0.512 5 0.008 99. 997 0.003 0.326E-04 Flow Duration from Time Series File:dsout.tsf Cutoff Count Frequency CDF Exceedence Probability CFS o % % 0.007 33305 54.313 54. 313 45. 687 0. 457E+00 0.022 6006 9.795 64. 108 35.892 0.359E+00 0. 036 5276 8.604 72.712 27.288 0.273E+00 0. 051 4865 7 .934 80. 646 19.354 0. 194E+00 0. 065 4197 6.844 87.490 12.510 0. 125E+00 0. 080 2937 4 .790 92.280 7.720 0.772E-01 0.094 1797 2 .931 95.210 4 .790 0. 479E-01 0. 109 1328 2 .166 97.376 2 .624 0.262E-01 0.124 1162 1.895 99.271 0.729 0.729E-02 0.138 91 0.148 99. 419 0.581 0.581E-02 0. 153 41 0.067 99.486 0.514 0.514E-02 0.167 24 0.039 99.525 0.475 0.475E-02 0. 182 28 0.046 99.571 0.429 0.429E-02 0. 196 30 0.049 99. 620 0.380 0.380E-02 0.211 19 0.031 99. 651 0.349 0.349E-02 0.225 17 0.028 99.679 0.321 0.321E-02 0.240 11 0.018 99.697 0.303 0.303E-02 0.254 16 0.026 99.723 0.277 0.277E-02 0.269 9 0.015 99.737 0.263 0.263E-02 0.283 13 0 .021 99.759 0.241 0.241E-02 0.298 23 0.038 99.796 0.204 0.204E-02 0.312 11 0.018 99. 814 0.186 0. 186E-02 0.327 13 0.021 99. 835 0.165 0. 165E-02 0.341 11 0.018 99.853 0.147 0. 147E-02 0.356 11 0.018 99.871 0.129 0. 129E-02 0.370 7 0.011 99.883 0.117 0.117E-02 0.385 9 0.015 99.897 0.103 0.103E-02 0.399 7 0.011 99. 909 0.091 0. 913E-03 0.414 11 0.018 99. 927 0.073 0. 734E-03 0.428 15 0.024 99. 951 0.049 0. 489E-03 0.443 6 0.010 99. 961 0.039 0. 391E-03 0.458 6 0.010 99. 971 0.029 0.294E-03 0.472 4 0.007 99. 977 0.023 0.228E-03 0.487 3 0.005 99. 982 0.018 0. 179E-03 0.501 4 0.007 99. 989 0. 011 0. 114E-03 0.516 5 0.008 99. 997 0 . 003 0.326E-04 Duration Comparison Anaylsis Base File: predev.tsf O 2015 D. R.STRONG Consulting Engineers Inc. Page 41 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 New File: dsout.tsf Cutoff Units: Discharge in CFS -----Fraction of Time----- ---------Check of Tolerance------- Cutoff Base New oChange Probability Base New oChange 0.124 � 0.95E-02 0.71E-02 -25. 6 I 0.95E-02 0. 124 0. 121 -2 . 4 0.158 � 0.63E-02 0.50E-02 -21 . 4 � 0. 63E-02 0. 158 0. 129 -18 .3 0.192 � 0.50E-02 0.39E-02 -20.4 � 0.50E-02 0. 192 0.158 -17.5 0.226 � 0.37E-02 0.32E-02 -14.1 � 0.37E-02 0.226 0.199 -11. 9 0.260 � 0.28E-02 0.27E-02 -6.3 I 0.28E-02 0.260 0.247 -4 . 9 0.294 � 0.22E-02 0.21E-02 -5.1 � 0.22E-02 0.294 0.290 -1. 4 0.328 � 0. 15E-02 0. 16E-02 11. 1 � 0.15E-02 0.328 0.342 4 .2 0.362 � O. 10E-02 0.12E-02 21.0 � O.10E-02 0. 362 0.387 7 .0 0.396 � 0. 62E-03 0.91E-03 47.4 � 0.62E-03 0.396 0. 421 6.3 0.430 � 0.34E-03 0.49E-03 42. 9 � 0.34E-03 0. 430 0.447 4 . 0 0.464 � 0.21E-03 0.28E-03 30.8 � 0.21E-03 0. 464 0.483 4 . 1 0. 497 � 0. 16E-03 0. 13E-03 -20.0 � 0.16E-03 0.497 0. 492 -1 . 1 0.531 � 0. 11E-03 O.00E+00 -100.0 � 0. 11E-03 0. 531 0.504 -5 .2 0.565 � 0. 16E-04 O.00E+00 -100.0 � 0. 16E-04 0. 565 0.517 -8 . 6 Maximum positive excursion = 0. 036 cfs ( 9.80) occurring at 0.368 cfs on the Base Data:predev.tsf and at 0.404 cfs on the New Data:dsout.tsr Maximum negative excursion = 0. 032 cfs (-18. 70) occurring at 0 .172 cfs on the Base Data:predev.tsf and at 0. 140 cfs on the New Data:dsout.tsf �2015 D.R.STRONG Consulting Engineers inc. Page 42 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 Peaks Plot Ratum Pzriod 2 5 10 2Q 50 10�� o rdout.pks in Sea-Tzc ♦ dwut.pks � �'2d�V.y'�4 � • rdin.p4s • • • � � • 10° • iy^i R '� � O V d Q rn � `m � t � � p � ♦ � ♦ 10� ♦ c i0Z 1 2 5 10 20 30 40 5D 60 70 8� 90 95 °8 99 Cumulafive Probabitity Duration Curve � 0 rdouLdur o dsout.d�r • tar,c,et.dur � m � R o--` � ��4 � w a U � m �� `m L f`7 Q O N O 000 �.` OD 0 0 � � i i I I io3 ��o' �o-' �o-Z �o-' io° i Proba6i- Ezceedence �I. �2015 D. R.STRONG Consulting Engineers Inc. Page 43 of 44 Storm�vater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 i Water Quality Treatment Basic Water Quality Treatment will be provide per Vol. V, Chapter 3 of the Manual, the treatment goal is 80% removal of total suspend solids for a typical rainfall year, assuming typical pollutant concentrations in urban runoff. A basic wetpond is provided to meet this requirement. The analysis is below. Rainfall(R)of the mean annual storm = 0.47 in. From KCSWDM Fig. 6.4.1.A Area of impen,ious surface(Ai)= 207,566 s.f. Area of till soil covered with till grass(Atg)= 180,371 s.f. Area of till soil co�,ered with till forest(At�= 0 s.f. Area of outwash soil co�,ered with grass or forest(Ao)= 0 s.f. Volume factor(�= 3 N/A From KCSWDM Sec. 6.4.1.1 Calculations Units Notes Volume of runoff from mean annual storm (Vr}= 9082.822 c.f. =(0.9Ai + 0.25Atg+ 0.10Atf+ 0.01Ao)* R/12 Minimum Wetpool wlume required(Vb)= 27,248 c.f. =f"Vr Therefore, the total wetpool volume required is 27,248 c.f. The wetpond provides 35,071 c.f. O 2015 D.R.STRONG Consulting Engineers Inc. Page 44 of 44 Stormwater Pollution Prevention Plan The Enclave at Bridle Ridge June 23,2014 APPENDIX "E" DECLARATION OF COVENANT 02015 D. R.STRONG Consulting Engineers Inc. The Enclave at Bridle Ridge Page 62 Technical Information Report City of Renton Return Address: City Clerk's Office City of Renton 1055 S Grady Way Renton,WA 98057 DECLARATION OF COVENANT FOR INSPECTION AND MAINTENANCE OF STORMWATER FACILITIES AND BMPS Grantor: PNW Holdings,LLC Grantee: City of Renton Legal Description: Attached Assessor's Tax Parcel ID#: 142305-9122&-9023 IN CONSIDERATION of the approved City of Renton subdivision permit for application file No. LUA/SWP LUA 14-000241 relating to the real property("Properly") described above,the Grantor(s),the owner(s) in fee of that Property,hereby covenants(covenant)with the 'i City of Renton, a political subdivision of the state of Washington,that he/she(they)will observe, consent to, and abide by the conditions and obligations set forth and described in Paragraphs 1 through 10 below with regard to the Property, and hereby b ants(grant)an easement as described in Paragraphs 2 and 3. Grantor(s)hereby grants(grant), covenants(covenant), and agrees(agree)as follows: 1. The Grantor(s) or his/her(their) successors in interest and assigns("Owners of the described property") shall at their own cost,operate,maintain, and keep in good repair,the Property's stormwater facilities and/or best management practices("BMPs") constructed as required in the approved construction plans and specifications on file with the City of Renton and submitted to the City of Renton for the review and approval of permit(s) LUA14-000241 . The properiy's storm��ater facilities and/or best management practices("BMPs")are sho��vn and/or listed on E�ibit A. The property's stormwater facilities and/or BMPs shall be maintained in compliance with the operation and maintenance schedule included and attached herein as E�ibit B. Storm��ater facilities include pipes, swales, tanks,vaults, ponds, and other engineered structures designed to manage and/or treat stormwater on the Property. Stormwater BMPs include dispersion and infiltration devices,native vegetated areas,permeable pavements,vegetated roofs,rainwater harvesting systems, reduced impervious surface coverage, and other measures designed to reduce the amount of stormwater runoff on the Property. 2. City of Renton shall have the right to ingress and egress over those portions of the Property necessary to perform inspections of the stormwater facilities and BMPs and conduct maintenance activities specified in this Declaration of Covenant and in accordance�vith RMC 4-6-030. 3. If City of Renton determines that maintenance or repair work is required to be done to any of the stormwater facilities ar BMPs,City of Renton shall give notice of the specific maintenance and/or repair work required pursuant to RMC 4-6-030. The City shall also set a reasonable time in which such Page 1 of 3 Form Approved by City Attorney 10/2013 $t}ff�. . . � � ' ,� a� work is to be completed by the Owners. If the above required maintenance or repair is not completed within the time set by the City,the City may perform the required maintenance or repair,and hereby is given access to the Property, subject to the exclusion in Paragraph 2 above, for such purposes. Written notice will be sent to the O�vners stating the City's intention to perform such wark. This work will not commence until at least seven(7)days after such notice is mailed. If,�vithin the sole discretion of the City,there exists an imminent or present danger,the seven (7)day notice period will be waived and maintenance and/or repair work will begin immediately. 4. If at any time the City of Renton reasonably determines that a stormwater facility or BMP on the Property creates any of the hazardous conditions listed in RMC 4-4-060 G or relevant municipal successor's codes as applicable and herein incorporated by reference, the City may take measures specified therein. 5. The Owners shall assume all responsibility for the cost of any maintenance or repair work completed by the City as described in Paragraph 3 or any measures taken by the City to address hazardous conditions as described in Paragraph 4. Such responsibility shall include reimbursement to the City within thirty(30)days of the receipt of the invoice for any such work performed. Overdue payments«ill require payment of interest at the current legal rate as liquidated damages. If legal action ensues,the prevailing party is entitled to recover reasonable litigation costs and attorney's fees. 6. The Owners are hereby required to obtain written approval from City of Renton prior to filling, piping, cutting, or removing vegetation(except in routine landscape maintenance) in open vegetated stormwater facilities(such as swales,channels, ditches,ponds, etc.),or performing any alterations or modifications to the stormwater facilities and BMI's referenced in this Declaration of Covenant. 7. Any notice or consent required to be given or otherwise provided for by the provisions of this Agreement shall be effective upon personal delivery, or three(3)days after mailing by Certified Mail, return receipt requested. ' 8. With regard to the matters addressed herein,this agreement constitutes the entire agreement between the parties, and supersedes all prior discussions,negotiations, and all agreements whatsoever whether oral or written. 9. This Declaration of Covenant is intended to protect the value and desirability of the real property described above, and shall inure to the benefit of all the citizens of the City of Renton and its successors and assigns. This Declaration of Covenant shall run with the land and be binding upon Grantor(s),and Grantor's(s')successors in interest,and assigns. 10. This Declaration of Covenant may be terminated by execution of a��-ritten agreement by the Owners and the City that is recorded by King County in its real property records. IN WITNESS WHEREOF,this Declaration of Covenant for the Inspection and Maintenance of Storinwater Facilities and BMPs is executed this day of , 20 GRANTOR, owner of the Prope►-ty GRANTOR, owner of the Property Page 2 of 3 Form Approved by City Attorney 10/2013 STATE OF WASHINGTON ) COiJNTY OF KiNG )ss. On this day personally appeared before me: ,to me known to be the individual(s)described in and who executed the within and foregoing instrument and acknowledged that they signed the same as their free and voluntary act and deed, for the uses and purposes therein stated. Given under my hand and official seal this day of , 20 Printed name Notary Public in and for the State of Washington, residing at My appointment expires , ' � Page 3 of 3 Form Approved by City Attorney 10/2013 . , � . ;;;r.;�, >� , LEGAL DESCRIPTION PARCEL A: PARCEL B CITY OF RENTON LOT LINE ADJUSTMENT LUA14-000250, RECORDED UNDER RECORDING NUMBER 20140606900004, RECORDS OF KING COUNTY, WA. PARCEL B: LOT 6 OF KING COUNTY TESTAMENTARY DIVISION NO.: L08M0034, RECORDED AUGUST 12, 2008 UNDER RECORDING NO. 20080812900004, KING COUNTY, WASHINGTON. BEING NORTHWEST QUARTER OF THE SOUTHWEST QUARTER OF THE SOUTHEAST QUARTER OF SECTION 14, TOWNSHIP 23 NORTH, RANGE 5 EAST, W.M., KING COUNTY WASHINGTON: I '�C� !� !(�..n-l.! ','l�. ,- -r- rl,� Ti i�- 1.,,;��.�T ., . .T.�T i � i i i i i i i i i i _- � I � BASIC DISPERSION 1/lA - - � � ' I� SPLASH BLOCKS FOR -� I � ; i' EACH RESIDENCE r0 I � � 'I BE USED FOR FLOW � � CONTROL BMP (TYP.) I 1 � � � � � � � ADA I i - i � � I � i I I i i i I � i i W � �� i Q I ~ I -- - � I �� I t I � � i i i � i i i I � i � RO B � I i �- � + I ' f I I 1 ' l ' � / , _ � �� ----------, �--, � �---- ------1 � I � � I i COMBINED DETENTION/WET POND�`,` \ I .,� i i '`•. �� `,. � NORTH GRAPHIC SCALE 0 60 120 180 `� � EXHIBITA 1 INCH = 120 FT. EXHIBIT B OPERATION AND MAINTENANCE SCHEDULE Combined Detention/Wet Pond Routine maintenance for the combined detention/wet pond consists of periodically removing accumulated sediment and debris; checking the inlet/outlet pipes and removing any sediment or debris blocking the pipes; properly removing/disposing of any visible oil sheen from the water; checking the pond sides and berms for signs of erosion or settlement; removing accumulated sediment from the pond bottom; and inspecting the rock pads at the pond outfall for missing rock. Perform inspections of all components quarterly during the first year of operation, then at least annually thereafter. The detention facility should also be inspected after major storm events. Basic Dispersion via Splash Blocks Dispersion devices must be inspected annually and after major storm events to identify and repair any physical defects. When native soil is exposed or erosion channels are present, the sources of the erosion or concentrated flow need to be identified and mitigated. Concentrated flow can be mitigated by leveling the edge of the pervious area and/or realigning or replenishing the rocks in the dispersion device, such as in rock pads and gravel filled trenches. The vegetated area over which runoff is dispersed must be maintained in good condition free of bare spots and obstructions that would concentrate flows. ,� ; �::� �_ �?� �, :�� ,�, . t� y -.� � �:. � _ �.*, � .t�,: _ �.� � � � �� RECORDING REQUESTED BY AND WHEN RECORDED MAIL TO: CITY CLERK'S OFFICE CITY OF RENTON 1055 SOUTH GRADY WAY RENTON, WA 98057 _ DECLARATION OF COVENANT FOR MAINTENANCE AND INSPECTION OF FLOW CONTROL BMPS I Grantor: PNW Holdings,LLC Grantee: City of Renton Legal Description: Attached Additional Legal(s)on: Assessor's T�Parcel ID#: 142305-9122&-9023 IN CONSIDERATION of the approved City of Renton(check one of the following) ❑ residential building permit, ❑ commercial building permit, ❑ clearing and grading permit, � subdivision permit, or ❑ short subdivision permit for Application File No. LUA/SWP LUA 14-000241 relating to the real properly("Properly")described above, the Grantor(s),the o�vner(s) in fee of that Property,hereby � ..,. ' � ", covenants(covenant)with City or Renton, a political subdivision of the state of Washington,that he/she(they)will observe, consent to,and abide by the conditions and obligations set forth and described in Paragraphs 1 through 8 below with regard to the Property. Grantor(s)hereby grants(grant), covenants(covenant), and agrees(agree)as follows: 1. Grantor(s)or his/her(their)successors in interest and assib s("Owners")shall retain,uphold, and protect the stormwater management devices, features,pathways, limits,and restrictions,known as flow control best management practices("BMPs"), shown on the approved Flow Control BMP Site Plan for the Property attached hereto and incorparated herein as E�chibit A. 2. The Owners shall at their own cost, operate,maintain,and keep in good repair,the Property's BMPs as described in the approved Design and Maintenance Details for each BMP attached hereto and incorporated herein as E�ibit B. 3. City or Renton shall provide at least 30 days written notice to the Owners that entry on the Property is planned far the inspection of the BMPs. After the 30 days,the Owners shall allow the City of Renton to enter for the sole purpose of inspecting the BMPs. In lieu of inspection by the City,the ,, Owners may elect to engage a licensed civil engineer registered in the state of Washington��vho has expertise in drainage to inspect the BMPs and provide a written report describing their condition. If the engineer option is chosen,the Owners shall provide written notice to the City of Renton within fifteen days of receiving the City's notice of inspection. Within 30 days of giving this notice,the Owners, or the engineer on behalf of the O��ners, shall provide the engineer's report to the City of Renton. If the report is not provided in a timely manner as specified above,the City of Renton may inspect the BMPs without further notice. 4. If the City detennines from its inspection, or from an engineer's report provided in accordance with Paragraph 3,that maintenance, repair,restoration,and/or mitigation��ork is required for the BMPs, The City shall notify the Owners of the specific maintenance, repair,restoration,and/or mitigation�vork (Work)required under RMC 4-6-030. The City shall also set a reasonable deadline for completin�the Work or providing an engineer's report that verifies cotnpletion of the Work. After the deadline has passed,the O��ners shall allow the City access to re-inspect the BMPs unless an engineer's report has been provided verifying completion of the Work. If the��ork is not completed properly within the time frame set by the City,the City may initiate an enforcement action. Failure to properly maintain the BMPs is a violation of RMC 4-6-030 and may subject the Owners to enforcement under the RMC 1-3, including fines and penalties. 5. Apart from performing routine landscape inaintenance,the Owners are hereby required to obtain �vritten approval from the City or Renton before perfonning any alterations or modifications to the BMPs. 6. Any notice or approval required to be given by one party to the other under the provisions of this Declaration of Covenant shall be effective upon personal delivery to the other party, or after three(3) days from the date that the notice or approval is mailed with delivery confirmation to the current address on record�vith each Party. The parties shall notify each other of any change to their addresses. 7. This Declaration of Covenant is intended to promote the efficient and effective management of surface water drainage on the Property,and it shall inure to the benefit of all the citizens of the City of Rento�i atid its successors and assigns. This Declaration of Covenant shall run�vith the land and be bindi�lg upon Grantor(s), and Grantor's(s') successors in interest and assigns. 8. This Declaration of Covenant may be terminated by execution of a written agreement by the Owners and the City of Renton that is recorded by King County in its real property records. � � + I �. � �� ; ; IN WITNESS WHEREOF,this Declaration of Covenant far the Maintenance and Inspection of Flow Control BMPs is executed this day of ,20 GRANTOR,owner of the Property GRANTOR,owner of the Property STATE OF WASHINGTON ) COLJNTY OF KING )ss. On this day personally appeared before me: ,to me known to be the individual(s) described in and who executed the within and foregoing instrument and acknowledged that they signed the same as their free and voluntary act and deed, for the uses and purposes therein stated. Given under my hand and official seal this day of ,20 Printed name Notary Public in and for the State of Washington, residing at My appointment expires LEGAL DESCRIPTION PARCEL A: PARCEL B CITY OF RENTON LOT LINE ADJUSTMENT LUA14-000250, RECORDED UNDER RECORDING NUMBER 20140606900004, RECORDS OF KING COUNTY, WA. PARCEL B: LOT B OF KING COUNTY TESTAMENTARY DIVISION NO.: L08M0034, RECORDED AUGUST 12, 2008 UNDER RECORDING NO. 20080812900004, KING COUNTY, WASHINGTON. BEING NORTHWEST QUARTER OF THE SOUTHWEST QUARTER OF THE SOUTHEAST QUARTER OF SECTION 14, TOWNSHIP 23 NORTH, RANGE 5 EAST, W.M., KING COUNTY WASHINGTON: LESS NORTH 100 FEET OF THE WEST 440 FEET. .�S• , "%ti - ..e��; . . . , .. . .. _ � .' ... ' � �, �S i ' • ' ' � � I , I � � � I I I I I I � ' BASIC DlSPERSION l//A I - - ' I� SPLASH BLOCKS FOR -� I I i ' EACH RESIDENCE TO i � ; I BE USED FOR FLOW � , CONTROL BMP (TYP.) I � � � I I � AD A I i - i � � I I i I I i i i I � i i W � �� i Q I � i � � I I i i � I i i i I I i I � i j ' RO B I I i I � � I I � � l , , ,� � - r------------, ,--, � �---- - -1 � ---- � I � I i COMBINED DETENTION/WET POND�`.. '\ '�, I � \ � � �`�� `�� I f� NORTH GRAPHIC SCALE 0 60 120 180 `� � EXH/BIT A 1 INCH = 120 FT. FLOW CONTROL BMP S/TE PLAN EXHIBIT B ❑ TEXT OF INSTRUCTiaNS FC}R BASIC dISPERSION Yc�ur praperty cantains a stom�wafer managemenf 8ow confrol BMP€besf management pr�ctice)cafled "i�asic dispersion,'which was insfalled to mitigate fhe sEormwater quantity arxi quaGty impacts of some or all of the impervious surfaces or rton-native pervious surfaces on your property_ Basic dispersion is a strategy iar ukilEzing any available capac"dy of onsite�egetated areas fo refain,absorb,and fiRer the runoff iron�devetoped surfaces. This flow control BMP has fwo prim�ry comgonents that musf!te mainEained:(1) the devices that disp�rse runoff from th�dEV@I4P�d surfaces and(2)the veget�ted ar�ea o�er which runoff is dispersed. Dispersion devices The di�persion devices used on your pr�aperty include#he foilowing a�indicated on the Row coRtrol BMP site plan_�1(splae,h bloeks,0 mek pads,O gravel fiEled trenches,0 sheet flow. The size,placement, cQmpositlon,and dawnstream ftowpaths af these deviee�as depicted by the flow etantrot BMP site plan and d�sign d�fails must be mairrfained and may not F�e changed withouf w�ritfen approvaf either from the King Caunty INater and Land Resaurces Csivision or�raugh a future development pertnit from Ifing Caunty. Dl�per�ion devices mu�f be in�pected annualty and after major storm events ko identify and repair any physica{defects� When native s�il is erq�osed�or erosion channels 3r�present,the sourc�s of the ero:aon ar concentrafed 8ow need to be iden�ed and mitigafed. C�ncentrated fbw can be mitigated by leveiing the edge af the peroious ar�a andlor reafig ning ar replenishing the rocks in fhe dispersion device,such 3s in rock pads and gravel fiEled trenches_ Yegetated Flowpaths The vegetated area over which runoff is dispers�d must Ue mamtained in good condi�on free of bare spats and obsfructions that vr�uld�an�ntrate ftows. FIGURE�3.�1� TIYI�C'AL SPL3S�B'LUC7i F{?R B.�SIC DISPER5I01\T house ! roaf � downspoui s�rves up to 700 s.f_ afroof 5Q'min_ vege+ated flouv pa'h , splash hlocic �� downspart extension NTS sptasn �hfo� ��-� S '��`�. . . . J� . APPENDIX "F" LEVEL ONE DOWNSTREAM ANALYSIS ��d�.`3 . ' ' .. . . �4" . . . :'::� G2015 D. R.STRONG Consulting Engineers Inc. The Endave at Bridle Ridge Page 63 Technical Information Report City of Renton LEVEL ONE DOWNSTREAM ANALYSIS for THE ENCLAVE AT BRIDLE RIDGE Preliminary Plat 14038 156`h Avenue SE, Renton,Washington �� A� J�U �� og �tiAS,Yj�� Ijf � �P c�'o � 2 r � � x � =�' a _�: ,� �,��2�z� , �SSI O\r L F�` DRS Project No. 13117 Renton File No. U14005368 Owner/Applicant PNW Holdings LLC 9675 SE 36th Street, Suite 105 Mercer Island, WA 98040 Reporf Prepared by � � D. R. STRONG Consulting Engineers, Inc. 620 7t" Avenue NE Kirkland WA 98033 (425) 827-3063 Report Issue Date February 20, 2014 Report Revision Date February 9, 2015 02014 D. R.STRONG Consulting Engineers Inc. LEVEL ONE DOWNSTREAM ANALYSIS THE ENCLAVE AT BRIDLE RIDGE TABLE OF CONTENTS TASK 1 DEFINE AND MAP THE STUDY AREA .........................................................2 TASK2 RESOURCE REVIEW.....................................................................................6 TASK 3 FIELD INSPECTION .....................................................................................16 UpstreamTributary Area............................................................................................16 General Onsite and Offsite Drainage Description ......................................................16 TASK 4 DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS ...17 Drainage System Description.....................................................................................17 Downstream Path NDA 1 ........................................................................................17 DownstreamPath NDA 2........................................................................................18 TASK 5 MITIGATION OF EXISTING OR POTENTIAL PROBLEMS.........................19 List of Figures Figure1. Vicinity Map ......................................................................................................3 Figure2. Site Map ...........................................................................................................4 Figure 3. King County iMap Topography .........................................................................5 Figure 4. Streams and 100-Year Floodplains and Floodway ...........................................7 Figure 5. King County iMap Wetlands..............................................................................8 Figure 6. King County iMap Erosion Hazard Areasqs .....................................................9 Figure 7. King County iMap Landslide Hazard Areas ....................................................10 Figure 8. King County iMap Seismic Hazard Areas.......................................................11 Figure 9. FEMA— Flood Insurance Rate Map................................................................12 Figure 10. King County iMap Drainage Complaints.......................................................13 Figure 11. USDA King County Soils Survey Map ..........................................................14 Figure 12. Downstream Table........................................................................................22 Figure13. Downstream Map..........................................................................................25 02014 D. R.STRONG Consulting Engineers Inc. Page 1 Level One Downstream Analysis The Enclave at Bridle Ridge City of Renton r ��, . � . . � . . . � DISCLAIMER: THIS REPORT WAS PREPARED AT THE REQUEST OF PNW HOLDINGS, LLC FOR THE 8.807 ACRE PARCELS KNOWN AS A PORTION OF THE SOUTHEAST QUARTER OF SECTION 14, TOWNSHIP 23 NORTH, RANGE 5 EAST, W.M., IN KING COUNTY, TAX PARCEL NUMBERS 1423059122, 1423059023 (SITE). D. R. STRONG CONSULTING ENGINEERS INC. (DRS) HAS PREPARED THIS REPORT FOR THE EXCLUSIVE USE OF DRS, THE OWNER, AND THEIR AGENTS, FOR SPECIFIC APPLICATION TO THE DEVELOPMENT PROJECT AS DESCRIBED HEREIN. USE OR RELIANCE ON THIS REPORT, OR ANY OF ITS CONTENTS FOR ANY REVISIONS OF THIS PROJECT, OR ANY OTHER PROJECT, OR BY OTHERS NOT DESCRIBED ABOVE, IS FORBIDDEN WITHOUT THE EXPRESSED PERMISSION BY DRS. TASK 1 DEFINE AND MAP THE STUDY AREA This Offsite Analysis was prepared in accordance with Core Requirement #2, Section 1.2.2 of the 2009 King County Surface Water Design Manual (Manual). The Site is located at 14038 156th Avenue SE in Renton, Washington. See Figure 1, Figure 2, and Figure 3 for maps of the study area. G2014 D. R. STRONG Consulting Engineers Inc. Page 2 Level One Downstream Analysis The Enclave at Bridle Ridge City of Renton FIGURE 1. VICINITY MAP LD = � � � :S��0. _ SE 17TT1�R d ' �sl'!1 S7 � SE 1iJiM R ---•- ,��i'MR �4< �+ sE�ri1 ST � � ��9� Ss 11q-N, at J�te SS STt R � ._. ' y c . y� t � � N ; { � � � ��tlS�� SE NN ST � d C � � � SE 7�2ND SI � SERTHSi d � � � _ sti tit2"n �+r+ov� __� � � � �'��_ . , tF�[tq0 iT � � SE tattp p� ,} . � � �, � ` SE 11.11M ST � � �z�� e � - , s4��irHcl. � � � `Pa � -- �� i ¢� ,,� ^ �� Q" 9fi 14i1f pi� �`` ` � � � �.'� , � ; � � � : �, m ��„P,. � - --- � ,.� � � � -G�,�-"-"-'__ - � : � �' _:..�.�-_� se,+4,H� s =\ � �_.�j � � SE e�§T l D � `1`��\ R r' �� L_ � � `�J� �Y�` ��/�—� r' ��-._. � �/ - � �Cedar River�_ _] � �' ''T ��"�.� d i �` � . ��--,�' � 3 � f� � 1 � � � ,�D� - , �� -, � �� 'rH a� � r �°° _ -_ � � S �: - =� . _-�� --- --:.�� # I � - -- t-,�. r sE�q �� --.- --`� �- _ - _-I � . y�os __ _ __- The information included on this map has been compiled by King County staff from a variety of sources and is subject to change without notice. King County makes no representations or warranties, express or implied, as to accuracy, completeness,timeliness, or rights to the use of such information.King County shall not be liable for any general,special, indirect, incidental,or consequential damages including, but not limited to, lost revenues or lost profits resulting from the use or misuse of the information contained on this map.Any sale of this map or information on this rnap is prohibited except by written permission of King County. 02014 D. R.STRONG Consulting Engineers Inc. Page 3 Level One Downstream Analysis The Enclave at Bridle Ridge City of Renton y � FIGURE 2. SITE MAP � i 02014 D.R.STRONG Consulting Engineers Inc. Page 4 Level One Downstream Analysis The Enclave at Bridle Ridge City of Renton Yf � �. 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I . - -, . . � R:\2013�J�13717\3\Orawirgs1Plots�/igures1App_=ndix A_Srte mop.dwg 2/11/2015 ]0:10:04 !,M P57 D/tA/NNG• RGURE Z COPIRIGHT �Q 2D74, D.R. STRONG COVSULTING ENGWEERS INC. SHEET.• I FIGURE 3. KING COUNTY IMAP TOPOGRAPHY j ' � `, �, L' �;; I I��'--:-_.`;-- '`.�;;,�,`�---.,� ��sr ��`� �- �-, . �` C-_---; �/�`-•', ` \-� _ `�„�-.� �`- � ��j` � � - � �------T- _ f i `y�~ Y �� ,� r ��----� � ��' 1~. ``�,._ � _j�_ � � � �. � ��'1"- � .. �,� `�� I�-.`< ��`�'`�'��'1 �l�`�-- `J � :� r'- -''� �`-��'L � �`'- � , � �.,�\' � -�� ,!'� `� _ ' ` ` - _ ��'�. �.� ,_l�� _ ,J �?,•�� `' '� � '\ \. �` lr�� r- , ^�' r�1^—�' f � (� Si�e ` . ` �� v� 1 ``�' �: l=� � �7 --:-'� ---- ��-_ -- � -`S �z ,"� - r=, _ _�, �- �� `�-z,.;_ � -=1�.t-- ? 11� �`� �,1-�JRento n � r C'� � , -� , t •'`~��y '^ ' '^� :�,,,.t_ , � ^-� ,`�_- , ( t J ��- JV y�� - _- ` 1�_ ,��-�,�� =J f'` � 7 t�. � t , , -� $£121ST PI. I Ol~"L-,} �_ - � �h fr � `i' � �� , { t/ � s L i1��-.��-� J�,1 -P,--��C,y'_1tC -_�_ �_ -� _ `��►`'"��-�,` _ _ ��1 l,�`ll 1 �L/�,'�� . � -1 N�S�'1 __ _ � 1• _'`-�rl�'1 �J .ti1 ��,y (,��. V �� . ^ -'�r _ �� , � �� - `� 3 �- Y t"'�` �r -`l .` 4,�TrpCt f.-1� ' ��! - �- ,.�� "l t- _�' _�� r'� � I ` 5�, �� _ L, l J^�``� `1`�� , 1�1flP[�� ,� � � ,��f�� ..;_..: , ,� � �' '` `'�''�-- i-j �Y �rf -� _, / ,� C- , �---�-✓-`- , � �� '` �,~� �'L r��"� � �� V I� T� &e t�po sr --.� 1 —` �.- = ''; '� ,(�r� ' � `` .�,.�--`� „_ t�f�. c �• � ,`y��,� r.�1__.��,. I ��-`��-� '` �� }'�i � �� a;� �(`��`1.--�-ti,�--�--�`c,• �� I �-, �, (,_'r �."1 �f�� ( �_ � �} r_� }r '} � r "� ' `�-- � �1- }1 t -� �, � ll"y F �, -1_ M� {� � -_ -- -f— _ -.- — --__— - SE_744iH ST_�-: � � �+ ,.' �`y �}; 4r ~� r� �� t'S.,% _ � �'--� '� � � �, f � ��►�� J�.� C_ jJ � � -�-�. _- `L' (� {� _.-" L � ��` � ,_,.J"t i r ' - � ,``ti •� � �(l 1 � ` � � � ��__ � l`t`�� I �l '��f�� ' �� - .1ti��.�� J ti.-��`; /]� / � �_'\� ! 1^Aj/r �� f ' . � .� ` �.5 ( �-r� ! c� s��;'tt, � `_.� -Z '�� ,r�_-� � �'\ �-'� � (5 'G � i� i. ,Y}I` t - --'`v 74 l'� �-_,.. 1� -- .` "`��5 ��' _ '1l l��1� Z � 't� !'�4I' 1 �=� ry� 1 .� �� _�� —� -1 J�� _,, �`_ �� "� � yr ^� �`'-�,£ , -� ��L �� r f 'j � � ,1 1_ � �� Z r ) .I �' J� ;-� . ..�1 � �,i �7yf; ` %);. �.._.��_!�- �J `- �,___�� e� �`_ C_�! ��j t i '� �� , y[j `y, (��}� 4t ss,.�m��- �- _ ___ �t _ - ,[�-`.�-� .__ . - . -- �. .��.�.; �.4��:•k'_. �il.l�..I IT',. I �. 1�4�' l- - � �--� Legend � Nighlighted Feature Highways � Lakes and Large Rivers �_� Courrty Boundary Streets �,,,1 5treams X Mountafn Peaks Nqhrv�y Contours{5ft dark) Anar� �f too:5oo:to00 LO� nf otnar Parcels t' 02014 D. R. STRONG Consulting Engineers Inc. Page 5 Level One Downstream Analysis The Enclave at Bridle Ridge City of Renton TASK 2 RESOURCE REVIEW • Adopted Basin Plans: Lower Cedar River Basin and IVonpoint Pollutron Action Plan was adopted in July 1998. • Floodplain/Floodway (FEMA) Map: No floodplains exist on site, See Figure 9. • Other Offsite Analysis Reports: None available af this time. • Sensitive Areas Folio Maps: See Figures 4-8 for documentation of the distance downstream from the proposed project to the nearest critical areas. Included, are sections of the King County Sensitive Areas Folio which indicate the following: • Figure 4 Streams and 100-Year Floodplains and Floodway: There is a C/ass 9 and Class 3 Stream within one mile of the Site along the downstream path. A 900-year floodplain is within one mile of the Site. • Figure 5 Wetlands: There are no mapped Wetlands within one mile of the Site along the downstream path. • Figure 6 Erosion Hazard: There are mapped Erosion Hazard Areas within one mile of the Site along the downstream path. • Figure 7 Landslide Hazard: There are mapped Landslide Hazard Areas within one mile of the Site along the downstream path. • Figure 8 Seismic Hazard: There are mapped Seismic Hazard Areas within one mile of fhe Site along the downstream path. , • DNRP Drainage Complaints and Studies: As shown in Figure �0, there are drainage complaints within 1 mile of the Site along the downstream path. • Road Drainage Problems: None noted. • USDA King County Soils Survey: See Figure 1?. • Wetlands Inventory: The wetland invenfory revealed no additional wetlands within the downstream path. • Migrating River Studies: None are applicable to the site. • Washington State Department of Ecology's latest published Clean Water Act Section 303d list of polluted waters: None listed along the downstream path. I • King County Designated Water Quality Problems: None at this time. I • Adopted Stormwater Compliance Plans: City of Renton Storm Water Management Plan; King County 20�3 Stormwater Management Plan • Basin Reconnaissance Summary Reports: Cedar River Current and Future I Conditions Report (April 1993) 02014 D. R.STRONG Consulting Engineers Inc. Page 6 Level One Downstream Analysis The Enclave at Bridle Ridge City of Renton �. ��, y , r� FIGURE 4. STREAMS AND 100-YEAR FLOODPLAINS AND FLOODWAY a ��m �+-tnrP , �.rH�a � s � �t � sEst»sr .. I � !E1]9THP! � �� gIAfNR ��1NR W Z y x � <': � 1�+ �I10INR � _ �gE � ��„a � � f � _-�n� Site � __ ^ d E 9[taiSf 0. � � - S � � � si ' �SE 1�y.�D ST-- �� 5E/W00. � � � � ______ - . :, 5��7':D �'DK y = � ' � � �.eqasr w il SE�cT�Da � 9E1t7RD0. ,'\ � � � � _ � . d � � M \ .`. _ . - - - - --s��uiH_sr- :-_ a � F � �e g. d '� sE wrH rt � M � � ��a �MA` � F \ d d � { i , � . � . p � �,r,Q' sE+anrsr - c � .: Q! �� g 4- Zy � lP °1 11 K d d -� Y � �ue,,,0. � �r � � W � �._'-_ 1� . < �.1'ir_�!+'tJ`;�:� � . � �'q�aa q sE�wrnsT � fJ, � / /� � f � S [f ' 1�� _'/i�. f//� �� 6C1�fNm � � f .. '- ��/ / / /�` `�� ..�,/ � p n t , � ^ / / ��..� �-�` / ;� k � ' � / i �7-� 7�r .1 ''�'/ .?V�I�1 ' 1 �-� \ �% 'Ceda�R;ve,+ a- '� \ M _ 1,�`k%�/j � / /j►i:� �0�, ` I � . Renton_._-''�__ �\��'•'//"_/'� `�� ,�' � - "'- �3�J �'�Lr`� � L„ � '�Oiy�� J� . � ��s�o,� . �: ,, �: �r"�`'r�" �"- `: ,- �' � -\ „�, f = �� . '' � �'� a oq o ,p ;� --- .-,�` �'� -- _ � _ _� � �� '�� '`� `.-%_ " � �� ( � f .'� �1--- � � -` �._I'� r�� t; _ 'r--- �- _ ,y �. , :. � ,, _.� g¢yQ� m _.__ - . __ ��`�sw.' C t � R a � ' 'r'''_?-:�`�'—�� ''�- \ �� $ � i s_ � , '__.___ � . SEAfNra 0 Lepend � Highlighted Feature 5A0 Stream � � Couniy Boundary � �� x Mountain Peaks � cuss2Pmcnn;� Highways � C�s2s,knon�d StreSts ,,f C�] , ' ��ph�,�y . llnctagdiad ' ,�� O Lakes and Large Rivers �� f+j 5treams Parcais � Flondway � 70U Year Floodplain Shaded Reliei 02014 D. R.STRONG Consulting Engineers Inc. Page 7 Level One Downstream Analysis The Enclave at Bridle Ridge City of Renton : h� FIGURE 5. KING COUNTY IMAP WETLANDS Q g�n aiama .ecn��w � '� �urr.p � � � ` SF4IMSf " . . i . �� gIHIMR � �p� SFibMR Y�l1N0. �I � � � w $ �� _ � � � ��x - �, � , � T� 56YQMR n �1fNi'f = i r �� sE 1.1.4i 0. Y � � ^ �T � - $ � � } �- SE�.12H0 Sf.. /i�OlOq � � r 1 �, 5E:a1�p 5'iRr�ST yaAP� S 5�010R 3 ` ] � . J4 4 g1010iT � � \ � awmx ` 1 � , � � d � �. . � d - I— s£+41HSi �: E j A �' . �l�Nq f � �� ., 1E1/[T11R � � � � � r '. _ �. .. . '-. '. t � � `9 _ � .. E � � �Q� 3 4SM 4f � b F 4�' \ ' ' ° � � � e tv i,� '3 d � F � � � � SE 1diN R C _ 1 . i- � " €'- � 4 ' � _ E. j i..� \ . t i . SI �ly��h � SE KRh f7 Z . . ! /1—_'=� ..\ .�i� z r . „�- �_ ��s � p = � �,.TMn E R � ,1u, / ' ' % ,��._s i�, ±�.� � { i � ,� , . Cedar River � � - - � I . - ' .80� e 1 \-.-;�e � ,-• ...�� 3 j 3 � •` �� Aav''"Est r ^ —_--` � R �• � � ��Y s�,a^�s� � 1 . ..0. . . ,^ ` i �� '?�� - : . �� $�, 5 -.�� _--_ 1� `�\i. x � �� r r�•�,TT"-��xc« � ! t 'a �� 3 � ` L , r � 7 � f �` �!, ;J \ � .c�m'�q ♦IN�}:Y _�.--•. , _ --_ � _-___-- - '— � ' _ ,` _ �� rJ r r I. ".\ � __.-3!REN1ON.uARE VA�11 � C�`'..2-....:i �s� -j Legend �*1 Highlighted Feature �uK lJ — � County Boundary �.oa I _ x Mountain Peaks Parcels Highways f—I Lakes and Large Rfvers I—! Streets f+/ Streams Hp� � SA01Nedand {cait) 02014 D. R.STRONG Consulting Engineers Inc. Page 8 Level One Downstream Analysis The Enclave at Bridle Ridge City of Renton FIGURE 6. KING COUNTY IMAP EROSION HAZARD AREAS d ��R �R,n i � � . � ..!C<Tryp� i- �G�m �}�� g zm st SE 19fM IL � t}r 6E I.mN 0. I 1 tr „ x� d $� Een�w ' I � Y � 3 � aimHx 4 - �� i. � � � g�n� � d y� sErr»cr <, i d € gussr�a � � (- . M �j-- � seun+nst- a � I C. YW�OR W � � � . . � SE`.�p SErtHA EwDOM �� . .�1 � � d � "�_- ��rna rt � � y . , g�a rr Y q I'- ; i . �o� scwaa � tl dF � " _ � 5E 1LTH St � � 3 � � �� ' �� d ,�a'� �f��NR � d � ` ��IYf�1R � � � � ..__.__"_' � � � � � � , ,,�� . � � � � P' SEll5fN57 ' .1 � � �` � M +'� Y w er y d dE ' 11 m SEWn�0. � � � s _ � � ' . . . : �' �t � k a. ;:•�' ,�>.��..,�-- . .. � � /�'. . � �� sEum.sr , --�.�j . -� � r - �_ 4� � - � R � � sE N.n�sr . 4 �� '�; ._ -- ,\ �R '� � . f, p � `Cedar River-• � � � � - I '�--' `, d i ��b � � I r � ��,., a +�,�� I 3 r --------- -- _ � ��i � = +: � ,� \� � � �^.`. ,`` � � � � ti " ` ^ �� x� ``� `----- � g ;� � _.. __ :�_ ��. `�'Z�:- r(��'"`_'- � � `, `, � , f �,- �:�_ _ n �r '7 `i lj, ��,ti �' � -. - . --- j ' _ — 'J��S�,.. �� l r J \ � � � ^' - � � _.. ._ . _ �� ,� � .SEt]v'ru�. St H[NI�Il.UA Legend � Highlighted Feature �n�h � � County Baindary �o� x Mountain Peaks Parcels Highways �1 Lakes and Large Rivers L_I Streets ��,'' Streams ppn,,,�, 5A0 Erosion t��1 02014 D.R.STRONG Consulting Engineers Inc. Page 9 Level One Downstream Analysis The Enclave at Bridle Ridge City of Renton FIGURE 7. KING COUNTY IMAP LANDSLIDE HAZARD AREAS �� ¢ g iXIN P� . 8[lfH R _ �� BF 1]Ij�� I � `,ti . g37MST � � . ��. ;; _ k �� ssum.ci �6srHA. �. � . i��`--�. iI � � � i sswrax �' � gwn��t � � � s � gnNsr = .. d � gu�srz � � . $�. 5E±�2HOSf __ �. p � iElTNET �'� � I� __ �f � d � �.. J_____ G . 5£tiZT� UqADPL � � � � ----�y�'�._�, .. . g,.mSf . � � . �I ��f � d _ �IL7RaR �1(/� , ,�, _ _...__ ..-� ` ---SEty7Hs7 �-. - � � ._. . I ` / ' � � j' .� � �i, � � � � __ tE d � sE�vr.�vt }� �l '.,�r r i' �' d yd �� . .7 � _�_/` �' � 4 i�,� ��?�� . �<S' Q- SEuiit�sY � . , %i .��i. � -�, � 'i J:'i . � � ,yec�' . �''/��j�! /�� /.� �, // �// �� $t yl � d4 %j�i�i��//��//�, ./y� ��'�f �� . � � d S�' d � i ://,��/%//,''�%��`.f�. ��' .�,!::1 � � .¢�a � � � I '�� -'1j��;�'��.f//%/ ://�%�%!�f%��,� < . _ r.` •/��i�`��/. '1, �,�, ��.�� .L�"� �` � f',', i ,/�, . i/i•: ti ,�Isr � .. '`�-.. . �.�./� � i . . �//�//j� `/j� ''i��l�.f�� ,� �/!j/ { � B i ., i / �/ � /' V/�� ti. sEiernsr � ' . �..' +,�;/��/ �`/�i��//��/�/�/��/�'� �',. � � �l. / ,�f '/ .11' :,� �:�� eR /.l,-�/%d�� /��! /�./r,�.�,�rs-�_ � � „�r } . �t� `•C!�/" /%1��/�j .=/i/,`�7;`�. / 7 � �'-- �� '�/�j��,�f��j/��j;�%`// '�`�- ��/ ICedar Rive�_, �A'Qv d i��f`l�� ./i i. // �/� `I%/ i.'/ !� � � `�� i � _ fd� � '�:til/��..f_i/�,.�/��_,./`/,/////.//.�//�% �` I A1 � -_ �� 'aaec�veaF _ ' I 3 � �'-'� k `.Y;`' �" ' --- '�� , �.� � ._=� � ��j �y\` �� _ ___ `� % 'r �� ,,.-`Ly__ '�r�� - g� �� -- ., .� � , , ,�r. :i/, ,;�� y� : f�; -, � � �� /f//i%/�/: , ;%•�Ma • _� , � � _ � -�''��- ..._�-._,_ ,�� ,,:/i� ��/��^�//�/�� y..'�S . .'/ . ,// � ..�/�i'i. . . .'/i.� .— . �.. . . . SE R[N(6N.lAA!*. f i ,,.� .,�- /- �/'E•''�7*i�4r -. . i ��/.�i � _ LOgCI}� � Highlighted Feature Anon,I. — ( County Baurtdary �od 1 _ x Mountain Peaks Parcels Highways f—i Lakes atrd Large RiVei's L—� Streets f,i 5treams ��ph� � SAOI.�ndslide (co�t) �2014 D. R. STRONG Consulting Engineers Inc. Page 10 Level One Downstream Analysis The Enclave at Bridle Ridge City of Renton I �_ FIGURE 8. KING COUNTY IMAP SEISMIC HAZARD AREAS a g,�x g�� .�ii'RH0. . Cf(P�I � . � ♦ . � � . g3TM5T . t � 4 � SE I]9Tif 3 d �''.�� . SE 1h1)�{ti � '� '. C9iMR �� . . � . �� . g taQfH 0. i � � �'. r � € ��T�fR � W 4 . SETHST . _. _ ti d w a_. S d � �u�a � ` _ � ' - ' �'-� : .� —�---i..J7N0 57. � Q.� �Rn ST � ' . Y t0i0 R � � a � __'�L �E��1� �3�DPL . �_ .. � d � � �` � � �'�._ � -sE,rnosr a y� E_ uww�� Y ec,nma'� �. ,i\� , p �+ d p i -- . d s[,.m' � � � d ` � . . � � ., . . .._ _. --�-- -se�arnsr �-. ` � . � . � � ��9 r� � , �...0. � � � e . - ._ :.. -�-�. . :� _ a,� � � � �„a g,ss,,,n 4� `'`,.� � u � � � � � � � � f,�\\\��'. � �� tl � ssum�P � � € `�-\\'' �� f �sY � a a _ � I ,�'c��_ ��`� � � %.`�� -. � 5� sFy�� . �seum.sr , ,� ;�1\�� . � �' � � g�,� l:_;. . -\ \ .��..�� . .. � � \�;,-��-�.,, ; . � _ :•�\`�� \��.��\�:=�\��\��`� � �\��.��.� �\L. �i,�,\� �� i'� _\\Cedar Riv r ` ;_:\`�k\\��-..,y�:`� �\ �-\�\� \�\�\�`:., �\?`��\�. � � �-•--��--� • �� t�+\\\\�� \�..��:�:�\��\��\�:`�\�� r� _. ��\�• \ �' �` �I\�Y'\ ` \ � .�.� �` ,•: � ��•\� `mw�`��\\��. �--.� �\�� `;� �'' � -..�..� �� .�•E`� �\ �...� `'��`\\�\ \\ a,� �, :\�\.� ��.`1�� sei �'4._R� � �s��\�\�� \ �� .\' �\� ��\�\. \�•`\\ \\t..,-� ��" � ��\ � \�, ��\.,x �,�OR- • ��`�� \`\\ rT\� \� -, �� \;�\\�� \\\o� ,,\� �� .��;�\�� , '�'�st ;�\�t �' `-`,o ��__��\�\\''.� \\\� �v\�\\\o\��`\�� i3�� - \� . �� D\ 1 ��\,�...` � \ ��,•. '- - � ��`\�ls t �-�� ``� a\�\� �\\\��`'� �\�_��`Y � \\'��1- .�\ �-��` �\��i\�'�`�\ � ;� `-- � � � `I�\\�'\\\,� ` ��'�\`\�\\\�\�-'�\��L� ��. �� \��\\�\��`,:�� .�� ! ��\�,�'��' �, �, .-' �` , � � \�. ,��' ��\\ ��'�"\ \, .�� ' ` �. �. � �� : : �� <\-<<:t=:��\�\\t�\ \' \\ ��, r\�, . , ��_ .�\�\\\�.\\\`-,�"��d uTori�i,w � �\\'\, .�'��\. ��. � ,��_��.`_�.�\�.�Rri'.ar_ .`.\�\��. �\�`. + `��\\'��\`�\,\��ti .�\�:\� _� �0[�C(t� � Highlighted Feature pn«uts — � Courny Boundary � 1 ! � Mountain Peaks Parcels Highways � Cakes and Large Rivers S#reets ��'` Streams - 41�ghway � 5A0 SeiSmic {contj 02014 D. R.STRONG Consulting Engineers Inc. Page 11 Level One Downstream Analysis The Enclave at Bridle Ridge City of Renton FIGURE 9. FEMA - FLOOD INSURANCE RATE MAP � � ACE �j 0 SE idQTH ru,cE 5 SE 14tS� Z MACE Q � � = 5 3 142ND S1R=tT `y1tID cc�ytST 5�.�(H��E FIACE 4� � z soun+� w �+� srnFEr E _' . SO�Twcqsr taiT-1 57RE�T '9 � � � � $ ; � h �� $� d 4R, i s� � � x 2.� SDUTHEA$T ta6iii � S�a�> t� NOTE: MAP AREA SHOWN ON THIS PANEL IS LOCATfD J WITHIN TOWNSHIP 23 NORTH AND RANGE 5 EAST. �Fs ZpNE AE / �°i,_ LEGEND � tiPCC:Ht FLOOI) H4ZAFU An"c..�ti INUf.I):�1CD [lY�141T-YEnR FIOOU ZONE A u...hw•�k.d�cvrn�n�k�wr.+crr.f. ZONE AE w.Y iLrr�.;�-�ar.m d•kminv�. ZONE AH fb.d�kyvh.a t t�� s k•r�u-�.dlv.� . �i prRG�p: �a.r d..l �I��.n.., a i�.�a. 20NE AO 1'a,.•I i4�ls:i i a. t;i•�'u.i.,R��: , !I��.w� �i il...yny t a..�� <l,t.� �N�.m�A+l fi..n�s rf,�.ywW i.m f�>J�,�:. �r4r2ii+d..�df�+.nn.l. ZONE A99 T•� h�pn�.•ierl Ir�m I�i�ec�x 0.w.1 I�. t�.l.v�l hul �W.vG�a� wa�+n ur�.L. ��.wnr�.n:�w,h.rx�Av.t�,m Arqr��i:i.,. ZONE V (!uJ�l fl.x.l �sith .+k.ir kv.rrl ��. ..r�.��:�.�a,��:�..a�a,.,r m e.r�m:.-,,i ZONE VE l•+.*+.+� a�.,�! xwh v�e�ain hv.vd ��. . �'.'. x'ti��i:h�a- 13ad cY.aK�v+s d.trrrn��.1 ;�c,y��; FI.OnpW.iY AREAS IV Z.ONf A[ � OTHER F1.00D ARE�15 ZONE% .+�.�e v sa�.yr.w awd:re.��i wo-,�., i�uA r.i�h mv1R dryAn ��1 Ir.. :�.-i 1 GYn v .viN J�.:�na�,.� .� , .. t wfir.vc Mb: ..xl p�.i.:iL.1.��r k�rn fr.,m Hxl�ear�:�.f. � OTftER ARETS . .(- ZONE% arttih Jekrm.w M M o�.v� ; 4.Klpa�i. ZONE D . , �.hnh �1..d husd. ,., .�n,�drm rnd. ��2014 D.R.STRONG Consulting Engineers Inc. Page 12 Level One Downstream Analysis The Enclave at Bridle Ridge City of Renton FIGURE 10. KING COUNTY IMAP DRAINAGE COMPLAINTS a - �.,,�� ' �. �I]ffN0. .�.f[RI�R Ery,_�,��/�y'3.:�" �. ti11�Mf - � � � r44 �� . �. Y3T1ST �.:3� �'�.. � I . . gt.]�TM0. d }¢ g�YlNol lifTM0. �� R x� � � �� a „� � i � SEfafN0. ' .^�'a": � . �n � �� SEI�OThR M Q . � - g11��5f �I _ . d € s,.4srrt � Si' � - j S f . � � ' '�3 1 �. . seianw5l__ � h��,,l �er��.r � II f[�WO0. � � � g _�tti . . SE5i1 , ��oy , : A � F YUAD0. � G � i .� �. � scia�asr `� q ' � � � g1Ri00. •� M x d yj Q �� - ! � �` l�t1� � M M , � . se�..rn r r`,� �S � r`,,4 Qr�R y ; d - $wn�t� M � � . � �'�T� - --. = - � .1� x �� r� � �y '•\ � � `�� r P �ra ��rn n {p � � ts�� ? 14.� . tls�.^,� �. . • 'P � '�_ .�� :. x il y ��;,I � �[ d � d g � � �� E � � � � �,�er �O ' F * � F�' [�� i F_:�_.v - ((��' i" -.,I/ .�"�� L7 � -• . . �� R '+�41lIIJI � SE✓7fNiT �`, V �J`1 �� 4.�� s, �� i r ` t': .i�: � ��y � < P � ae rirN ar � . � J r �\�� 'S! ' r �•�� 4=��1^i � � � 1 � , �ti.�4;. 4 ,�w � � , t.. ��o� - ' � � i . .. I � � , � �.�. 1CrdarRiv r ` �/:' �' � e� � �. � a ' b �` : ( _ � �... 3 d'�.�`��-_ �� b 'd'��i,�r` �� . � i �� - � �'�ca .-F � .� � % /�`� . � .� ^�i� �_ "°�,a, ? r � �;E _ � �-. 1 � � o a j/- - ; ��. i� � r�--�–�:.-�_—� � d $ � � - \� .�.� ',�! � � a�Lv '~ 1 ��,�R �v �''^'�__. ___ � ,��-�-:�. �---.�;� \ r . x `� : � _ -- -- - - _- p Y r �RlM�pia�.u4 �� S S �CMT��S� ��[,�Fi Ild � Solictod Paraal• � ��c'��'N � � Cuurity eaundary �u+m� � Mountaln Peaks � HlgAwars Parcola �J lnanrporated Area � �akas�nc!Lar��Rlyure Streets f/ StrEams {contE � ; Dra!naqe Comptalnts 02014 D.R.STRONG Consulting Engineers Inc. Page 13 Level One Downstream Analysis The Enclave at Bridle Ridge City of Renton � � • • - , � �¢�,. + �� '� kt T.��. � - "5';: ' �.. i . �j� �� l��'� s �:;�;� � 1 E� � � `� �� - t f f 'w �'`�" �r� �' � r'"'�` � g`,.*� ; .:r�r. � r �µ � ��` . �� K�rt � _� ;� ,�,, - . �� , �� *� 4;�. „ , .� } . . �� r 3 .�,.3 s � ...v' z . � � � E A� #.: $�'� d., ��'�� `j � :vr ' _ 4 '� x�a� a+�h� a, "�+. '� .%K 4 '� � f f,Q _ . . . ��"a'�'ei,. � �.s :�' . .. ... � - � �_.. `'.' �f. �+'x i --�n, � ��., .�t° sF �y�.�I. .+� � ,"�'w�e'`� .. . � . .. . � '�Y '+li .�k."'^ '_. - . -_ . � �s�� a: �. . .. . `1� � _�R �,� s. '6� , .� .. . k �; `�r'h 2`_- f.� _ _ t :"��r '�� . . . � �`� �� , . y� s . . .�. �t-s,� x �,b,� . . . - � � - � t�i _ -_ � . ` a I � ,�_ X � ', . � . . , .. z } ± . . . AgC�A � � 5 ,�_• . n i' � - � .� � � < � �* , ,�.:Y' �� #,��"t! � z�t'S . �'.-_- �' . . �,�ti',� ��#: - .t �# ��LS: �9' 1 ...t�`.a : � vr �� . � f - .' .y .�: r . '�''�" . i.:� � _ �.r�k.,r .�� Y�_± � . `�. .1r1 . i a-� ' ''; �- T �, � _ _, i.[ �w, d f a, ��". .Y � . � '-.� -C .� . t�s �'.'i,s. x�s'. . � � .�,�`�i: ��- r ,r.-� ��`�.``'� �+'; �R � � z `�- �,;�'�^�-. s � . A�{ >�k'� + ��,'-.. �� . a� �� '� � a�;. �: '-� �.'�' �'�;� "" � . ; .c. • 'r:,� : :, s,,�.? F . , u - _'ti:=:K +i`..yr , v '�t . . �. �'�� , • � .� �� :� �-- � -. .. _� +. O 1 � '� • � � - .�- - - • - �• - - - � - ' ��- � - • :•�, - � AgC—Alderwood gravelly sandy loam,6 to 15 percent slopes Map Unit Setting . Elevation: 50 to 800 feet I , • Mean annual precipitation:25 to 60 inches . Mean annual air temperature:48 to 52 degrees F • Frost-free period: 180 to 220 days Map Unit Composition • Alderwood and similar soils:95 percent • Minor components:5 percent Description of Alderwood Setting • Landform: Moraines,till plains • Parent material: Basal till with some volcanic ash • Properties and qualities • Slope:6 to 15 percent • Depth to restrictive feature: 24 to 40 inches to dense material , • Drainage class: Moderately weil drained • Capacity of the most limiting layer to transmit water(Ksat):Very low to moderately low(0.00 to 0.06 in/hr) • Depth to water table:About 18 to 37 inches • Frequency of flooding: None • Frequency of ponding: None • Available water capacity: Very low(about 2.5 inches) Interpretive groups • Land capability(nonirrigated):4s Typical profile • 0 to 12 inches: Gravelly sandy loam • 12 to 27 inches:Very gravelly sandy loam • 27 to 60 inches:Very gravelly sandy loam Minor Components Norma • Percent of map unit: 1 percent • Landform: Depressions Bellingham • Percent of map unit: 1 percent • Landform: Depressions Seattle • Percent of map unit: 1 percent • Landform: Depressions Tukwila • Percent of map unit: 1 percent • Landform: Depressions Shalcar • Percent of map unit: 1 percent • Landform: Depressions 02014 D. R.STRONG Consulting Engineers Inc. Page 15 Level One Downstream Analysis The Enclave at Bridle Ridge City of Renton �R �� i. .. TASK 3 FIELD INSPECTION UPSTREAM TRIBUTARY AREA In evaluating the upstream area, we reviewed King County iMAP aerial topography and imagery and conducted field reconnaissance to evaluate conditions and potential problems. The upstream area for the Site is approximately 3.35 acres, entering the Site in from the northern and eastern property lines. It is prudent to note that these areas are zoned for residential land uses and upon development may generate increased runoff. Each development, however, would be required to collect and convey this increased runoff per the requirements of the Manual. The current land cover of the ; upstream area appears to be forested and generating negligible runoff. GENERAL ONSITE AND OFFSITE DRAINAGE DESCRIPTION The 8.81 acre parcel is encompassed within one Threshold Discharge Area (TDA) with two natural discharge areas (NDA 1, NDA 2). Runoff is conveyed as sheet flow southwest across the property through dense vegetation and pasture and is directed towards the southwest corner of the Site. From there a concrete pipe inlet conveys water west to a catch basin at the southwest corner of the Site on the east side of 156tn Avenue SE. Runoff continues south in the conveyance system then flow is directed west as pipe flow at the intersection of 156th Avenue SE and SE 144t" Street. Runoff continues west across 154th Place SE and outlets to Stewart Creek, a Class 3 stream. This creek outlets to the Cedar River which eventually outlets to Lake Washington approximately 5.5 miles northwest of the Site. The Site's second natural discharge point (NDP) is approximately 237' east of NDP 1. Runoff exits the Site as sheet flow and converges with NDA 1 at Point B. Runoff from the developed Site will be collected and conveyed by a typical catch basin/ pipe network to a detention pond in the southwest corner of the Site. The pond will discharge to the conveyance system in 156th Avenue SE. �2014 D. R. STRONG Consulting Engineers Inc. Page 16 Level One Downstream Analysis The Enclave at Bridle Ridge City of Renton TASK 4 DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS DRAINAGE SYSTEM DESCRIPTION The downstream analysis is further illustrated and detailed in the Downstream Map and Downstream Table located in Appendix A1. The downstream area is located within the Cedar River basin; more specifically the Lower Cedar River sub basin. The downstream area was evaluated by reviewing available resources, and by conducting a field reconnaissance on January 16, 2014 under overcast/foggy conditions. Located within the TDA are two Natural Discharge Areas (NDA), NDA 1 and NDA 2. NDA 1 exits the Site approximately 230' east of the southwestern property corner. Runoff continues as sheet flow for approximately 230' over native vegetation and pasture until it enters a 12-inch concrete pipe inlet where it continues as pipe flow into a catch basin in 156�h Avenue SE. NDA 2 exits the Site approximately 150' west of the southeastern property corner. Runoff sheet flows west along the southern property line over native vegetation and � pasture and converges with NDA 1 at the 12-inch concrete pipe at the southwest corner of the Site. Downstream Path NDA 1 Point "A1" is the natural discharge point of NDA 1. Runoff is conveyed west across the southern property line as sheet flow and directed towards a concrete pipe inlet at the southwest corner of the Site (±0). From Point "A1" to Point "B1", runoff heads west as sheet flow to a 12-inch diameter concrete pipe (±0'-223'). Point "B1", concrete pipe inlet at the southwest corner of the Site (±223'). From Point "B1" to Point "C1", runoff heads west as concentrated flow to a 12-inch diameter concrete pipe (±223'-230'). Point "C1", runoff enters a Type 1 catch basin located on the east side of 156�h Avenue SE (±230'). From Point "C1" to Point "D1", runoff heads south as pipe flow via an 18-inch diameter Corrugated Metal Pipe (CMP). Trickle flow observed (±230'-475'). Point "D1", runoff enters a Type 1 catch basin on the east side of 156th Avenue SE (±475')- From Point "D1" to Point "E1", runoff heads west as pipe flow via an 18-inch CMP. Trickle flow was observed (±475'-507'). Point "E1", runoff enters a Type 1 catch basin located on the west side of 156t" Avenue SE (±507'). From Point "E1" to Point "F1", runoff heads south as pipe flow via an 18-inch diameter CMP. Trickle flow was observed (±507'-691'). C�2014 D. R. STRONG Consulting Engineers Inc. Page 17 Level One Downstream Analysis The Enclave at Bridle Ridge City of Renton �"-" - . - ..� Point "F1", runoff enters a Type 2 catch basin located on the west side of 156th Avenue SE (±691'). Runoff continues south as pipe flow via an 18-inch diameter CMP for approximately 192' where it enters either a buried catch basin or tees into another drainage pipe heading west at the intersection of 156th Avenue SE and SE 144th Street. Field investigation found no catch basin at this intersection, but according to City of Renton's GIS maps, stormwater runoff is directed west at this intersection. Runoff proceeds west as pipe flow via a 24-inch diameter CMP for approximately 665' passing through two catch basins before reaching a Type 2 catch basin on the east side of 154'h Place SE. Runoff continues as pipe flow for approximately 55' across 154th Place SE. Then it heads southwest as pipe flow for approximately 157' where it outlets to Stewart Creek. Runoff continues approximately 2,470' south down this stream until it outlets to Cedar River, which eventually outlets to Lake Washington approximately 5.5 miles northwest of the Site. Downstream Path NDA 2 Point "A2", is the natural discharge point of NDA 2 (±0'}. From Point "A2" to Point "B1", runoff heads west as sheet flow and converges with NDA 1 at Point "B1" (±0'-471'). 02014 D. R.STRONG Consulting Engineers Inc. Page 18 Level One Downstream Analysis The Enclave at Bridle Ridge City of Renton TASK 5 MITIGATION OF EXISTING OR POTENTIAL PROBLEMS A review of the King County Water and Land Resources Division — Drainage Services Section Documented Drainage Complaints within one mile of the downstream flow paths revealed six complaints within the last ten years. Drainage investigation reports attached in Appendix B1 (see table on page 20). Project runoff from the TDA will be coltected and released per the Manual's requirements to accommodate Flow Control Duration Standard Area, matching Forested Conditions for the 100-year peak flow (Level 3 flow control) and Basic Water Quality requirements. During construction, standard sediment and erosion control methods will be utilized. This will include the use of a stabilized construction entrance, perimeter silt fencing, and other necessary measures to minimize soil erosion during construction. ' The project should not create any problems as specified in Section 1.2.2.1 of the Manual and therefore is not required to provide Drainage Problem Impact Mitigation subject to the requirements of Section 1.2.2.2. 02014 D. R.STRONG Consulting Engineers Inc. Page 19 Level One Downstream Analysis The Enclave at Bridle Ridge City of Renton � Complaint Parcel Summary Recurring Type Required number Mitigation � 2006-0069 2323059123 Ditch design No 1 None, property flaw causes is on opposite water to flow side of river upstream and back up, flooding pasture and outbuildings 2008-0507 2323059123 Fallen tree 2' No N/A None, property down of is on opposite Madsen creek side of river bypass drainage culverts catching and ' stopping debris. Will dam up and cause more flooding 2008-0700 2323059123 Over topping of Not since 1 None, property bypass channel 12/2006 is on opposite and flooding analyslS side of river onto property 2009-0071 2323059205 Flooding due to No 1 None an improperly installed culvert. 2009-0653 2323059133 Old water tank No N/A None in river emitting some fumes that is killing the vegetation above 2011-1008 232305HYDR Illegal dumping No N/A None of two television sets at SE Jones Rd and 254th PI ��2014 D. R. STRONG Consulting Engineers Inc. Page 20 Level One Downstream Analysis The Enclave at Bridle Ridge City of Renton APPENDIX A1. OFFSITE ANALYSIS DRAINAGE SYSTEM TABLE & DOWNSTREAM MAP 02014 D. R.STRONG Consulting Engineers Inc. Page 21 Level One Downstream Analysis The Enclave at Bridle Ridge City of Renton FIGURE 12. DOWNSTREAM TABLE TDA 1, NDA 1 Basin: Cedar River Subbasin Name: Lower Cedar River Subbasin Number: N/A Symbol Drainage Drainage Component Slope Distance Existing Potential Observations of field inspector Component Type, Description From site Problems Problems resource reviewer, or resident Name, and Size Dischar e Type: sheet flow, Constrictions, under capacity, ponding, tributary area, likelihood of problem, See map swale, Stream, drainage basin,vegetation,cover, % 1/4 mi=1,320 ft overtopping,flooding, habitat or organism overflow pathways,potential impacts. channel, pipe, depth,type of sensitive area,volume destruction, scouring, bank sloughing, Pond;Size:diameter sedimentation,incision,other erosion Surface area A1 NATURAL 223'EAST OF SOUTHWEST t0' NONE NONE DISCHARGE POINT PROPERTY CORNER OBSERVED ANTICIPATED A1-61 WESTERLY SHEET NATIVE VEGETATION NONE NONE NO FLOW OBSERVED FLOW OBSERVED ANTICIPATED 61 PIPE INLET 12"�CONCRETE ±223' NONE NONE OBSERVED ANTICIPATED B1-C1 WESTERLY PIPE 12"V CONCRETE NONE NONE NO FLOW OBSERVED FLOW OBSERVED ANTICIPATED C1 CATCH BASIN -INLET(E) t230' NONE NONE -OUTLET(S) OBSERVED ANTICIPATED C1-D1 SOUTHERLY PIPE 18"�CMP NONE NONE TRICKLE FLOW OBSERVED FLOW OBSERVED ANTICIPATED D1 CATCH BASIN -INLET(N) ±475' NONE NONE -OUTLET(W) OBSERVED ANTICIPATED D1-E1 WESTERLY PIPE 18"0 CMP NONE NONE TRICKLE FLOW OBSERVED FLOW OBSERVED ANTICIPATED 02014 D. R.STRONG Consulting Engineers Inc. Page 22 Level One Downstream Analysis 156`�'Ave Assemblage City of Renton E1 CATCH BASIN -INLET(E) ±507' NONE NONE -OUTLET(S) OBSERVED ANTICIPATED E1-F1 SOUTHERLY PIPE 18"p CMP NONE NONE TRICKLE FLOW OBSERVED FLOW OBSERVED ANTICIPATED F1 CATCH BASIN -INLET(N) t691' NONE NONE DOWNSTREAM PATH INACCESSIBLE -OUTLET(S) OBSERVED ANTICIPATED BEYOND THIS POINT BECAUSE OF BURIED CATCH BASINS OR SOUTHERNLY PIPE TEES WITH WESTERLY PIPE AND DIRECTS RUNOFF WEST ALONG DIRT ROAD G1 CATCH BASIN -INLET(N) ±g83' BURIED CATCH NONE MAINTENANCE REQUIRED -OUTLET BASIN ANTICIPATED H1 CATCH BASIN -INLET(E) t1,180' FULL OF DEBRIS NONE MAINTENANCE REQUIRED -OUTLET ANTICIPATED 11 CATCH BASIN -INLET(E) ±1,330' FULL OF DEBRIS NONE MAINTENANCE REQUIRED -OUTLET ANTICIPATED J1 CATCH BASIN -INLET(E) ±1,525' FULL OF DEBRIS NONE MAINTENANCE REQUIRED -OUTLET SW ANTICIPATED 02014 D. R.STRONG Consulting Engineers Inc. Page 23 Level One Downstream Analysis 156'hAve Assemblage City of Renton TDA 1, NDA 2 Basin: Cedar River Subbasin Name: Lower Cedar River Subbasin Number: N/A Symbol Drainage Drainage Component Slope Distance Existing Potential Observations of field inspector Component Type, Description From site Problems Problems resource reviewer, or resident Name, and Size Dischar e Type: sheet flow, Constrictions, under capacity, ponding, tributary area, likelihood of problem, See map swale, Stream, drainage basin,vegetation,cover, % 1/4 mi=1,320 ft overtopping,flooding, habitat or organism overflow pathways,potential impacts. channel,pipe, depth,type of sensitive area,volume destruction, scouring, bank sloughing, Pond;Size:diameter sedimentation,incision,other erosion Surface area A2 NATURAL 150'WEST OF SOUTHEAST t0' NONE NONE DISCHARGE POINT PROPERTY CORNER OBSERVED ANTICIPATED A2-61 WESTERLY SHEET NATIVE VEGETATION FLOW B1 PIPE INLET NDA 2 CONVERGES WITH NDA 1 AT t471' NONE NONE POINT 61 OBSERVED ANTICIPATED 02014 D. R.STRONG Consulting Engineers Inc. Page 24 Level One Downstream Analysis 156`"Ave Assemblage City of Renton i , . .� � FIGURE 13. DOWNSTREAM MAP II '� �:, _ : . �`1.4P . - . . . . ' 02015 D.R.STRONG Consulting Engineers Inc. Page 25 Level One Downstream Analysis 156'"Avenue Assemblage Preliminary Plat City of Renton � W W L---------------------------- -- --- 2 � SE 139 TH PLACE ' � � _ _ , , , i I z � � I ; � ;------ ----- -- ----- -- ----- -- W � � � I I ; O ti � 3 � I ' � I I � 1 " � y � � 1 � ' ' � � � 4 � � ' � ji o � � � � � � � Z � � � � I � I � W � � � Q q Q � cn � 2 $ o � � � � I = I, ; W W � , I � , z � � � � � W , , � I � I , Q , , , , , II , � -------- � � � � SE 7TH STREET , , , ^ , , S�� I I , � � I , , I I , , , I I, , , , , I I ' , , , , , � % . � --- --------- --------------� I � A 1 2 � '� SE 142ND STREET ' %� C� � --- ------ ------ --- ,, -- -- ----- ----- ----- --------- � - --�-- - — I B1 SE 8TH STREET W W ---� � , I � . 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N O RT H , � , ��y •� ----- ---- ---J : 'Q; ;e; K1 •, � SE 144TH PLACE ��I I� GRAPHIC SCALE ` �� i ; � 0 100 200 300 \ \ � � � � aa�n er. aov ,\ �'\ ' I I�I I ao I 1 INCH =200 FT. vrraEcr Ba�c� �cv ``�, � `\ � , �� h vn�e azan2o�4 i �\ 1 I I A j i\�; �if�Q: ��7 �I ♦ ' R�\2013\S\131ll\3\Drnrings\Base\3DSMAP13117.dwg 1/30/2015 ll�1648 AM PST �AIMV(w � �� COPYRIGNT QQ 2074, D.R. SiF20NG CONSULTING ENGINEERS INC. SfEF/: � � r _� j. APPENDIX B1. DRAINAGE INVESTIGATION REPORTS ;�^..A:.- .. �.. .. . � .. � . � . ...�'.. �w .�, ', Mi �. 02015 D. R.STRONG Consulting Engineers Inc. Page 26 Level One Downstream Analysis 156`�Avenue Assemblage Preliminary Plat City of Renton 5: �'}:'_ . . ... . �i'• .T, . ' . . � " � _ N Z t -..�.. .. . ., , �(e-� . ' . . � . f.�' � Lp € .;g��. ' _ �� d � g�iT1 S7 � SE ibTfl Pi .;8E T1 Pl Gq 5E 57�N ST i � �'�� SE1]4TNR SI�` � ��.:ti�. d �, j s�srN st � i � � N � � ; � � �4ilTM PL 9E 7Try ST 0 � � � �_ SE 1�2N0 ST � SEaTHSt � � � - -_ . .�51�2�� NbdD PL d ' bl � € � - ; SE 10i0 S7 � � { 4 SE tf]RD Pi '� � A��; � � SE 1Litl 5T y � �.t ,� � 8f ,� d' '.� SE u[TM R. }N � � `�rt � rsr�� a` � � ��,, . d w � � � � � �,a �� ° �,�, �'' � �, �'� 2009-0653 �1� ; � � g�� d - - 2009-0071 � � � � __-__ - � _ � ��,s, � g, _._,_------.__.�_,�,�,(j � � r.��n .�� i' ��'�� I�_`�� x � � ,� --� �`1 t ` �-- i �� Cedar River__ .) I rt.: _._�'4+�i� d � i � --ZDQ6�'��69 � � �b� ' Y 2008-0507 � � y�,a,20�1-100;8 ,� � 2008-0700. _ � � o -- ..- _- - . � � q:� - _ _fr- � �-��,�-.. � } `c'~ _ �� - - - - -- '—_� � `'� - 02015 D. R.STRONG Consulting Engineers Inc. Page 27 Level One Downstream Analysis 156`''Avenue Assemblage Preliminary Plat City of Renton � ��g �� F1LE NO.: �0"�1-100� Department of Natural Resource� ADDRESS:SE Jones Roadand 254�h Place, Renton, 98058 F and Parks Jennifer Vanderhoof Water and Land Resourc�s Didisio� NAME: PHONE: 206.263.6533 DRAINAGE INVESTIC�ATIOfV REPORT DATE OF INVESTIGATION: 11-10-2011 FIELD INVESTIGATION INVESTIGATED BY: Virgil Pacampara � I went to the site on 11/10/2011 at 1:00 PM and investigated an illegal dumping. The complaint was about dumping of two large television sets at the end of the roadway,right in front of a road block sign that says"No Dumping°. I saw the two television sets at the edge of a turn-around area/culdesac of 149`"Ave.SE. I spoke to Mr. Billy Emerson,the properfy owner of house#1506 149�'Ave.SE.about the alleged illegal dumping. He told me that the dumping appeared to have happened ' during late night, and noticed it the following day.That he installed the"No Dumping Sign"to eliminate the illegal dumping on the site, but it appears that people still dumped stuff on the site. It appeared that the spot of the dumping is located within the road right of way of King County. I gave him our business card to call us incase it happens again. He gave his and his wife's phone numbers (his 206.661.3432; Patti-360-990-6617)for the records. I went to the other site as indicated on the complaint reports/e-mail.The second site is the location of a regional facility(DR0535).The site is along the paved walking trail that is parallel and north side of I-169 (between 149�'Ave. SE and 150th Lane SE.). I did not see any illegal dumping on the site particularly along the north end of cross culvert(concrete box culvert)and on the swale. I spoke to Sandra of KC Roads emergency number(206296.8100)on afternoon of 11/18/2011, and reported the result of the investigation.Sandra told me that the KC-Roads will take care of the complaints and will remove the televisions on the site. ----�s�� -- -- ' L' This is the frst site �` : ��.- �'_ �� ` �,',�.� �: � where the two � �' ` � television was `�L : , � - �. �. � allegedly dumped �,-� �� 2'»�� illegally along the road �� ; '�' • -�.�q. �"�` � right of way.A"No �.:�' ;y�l, �s-,� �?` Dumping"sign was N .� r y, � �,�:1 . , ��;; _ . installed by Mr. ��f��f ,�=, _ '�'}„- Emerson to eliminate NTS �'�,' �'' -� - �4'-, illegal dumping it still ` '�+��,, ` - �':, ; .r� ` -�� :� " _ re-occuring- :�' �_ �� ' -,� �- , �a- '.�.•..r,3 * ��' _ �} *-� � � � �� . ` :'��,�< . ` � � µa l . f � .Y' * � �� e.�• �;�, '�+ !� 7 w +�+� t+�4.4, :�', e ,r- - s.�"��s ; �-�� - . �'�y .� _ � � ` :� � �� • .� �c G� y t �. �* .t � � y i I �,,,�+� � ir � ,�� ;j ` r. s'',"- � _ �"r,��j :; C �. '1, J I � _ � x � r:: "_' � +� - :_ � �' 2 _ � �. - �� W_ � �, ` � . . t r .� _F �� -, �, . i�� - ��.�; ,'.7'�.l - �;.. t �i � . '�� -.a -...� '� i. j f�:!� �� +� • ' � t ` � This is the second site.I ► ;,{ �l,`� ��Y � .,_� , : - �•� did not see any illegal �.� � +' /�� '4+F �..y it .. ~•e y�-a .. � '� ',t ,- .. �,_. dumping on the site.The _ .,� �.,��_ i � � � ` ; ' site is a regional facility. ..,,. � r` ..'�t"� „, .x ;t -�a�. � ; �� ,�. ��.� ��, �,:.�.� : � � � �, �K�. _ � , ;, ,. , �`��j' ��± � �; � �e., r � '. � ' •t �.,� r � �� ^i.�p � �, '� d: T r . 1 . ,� . � ;g t�'�• 'j°� ' ' f� � �� r . ,. `" �, '* .. � - �,. �'�a: ; � ,��, � � � " �� . :' ��t' ,� � . • � _ � +�'r �� i . - � , i II' � .w��_ �� '�f ��I ` 'e� ,. . , f� }� �* ' , .• " '�f��'S�' ��j s '' `.i .� =.nl�� , _ `s'1" .k � � `�� } � �..`. i'_e _ ' . . .t . • %i;� �'�_�AtS�~�, ,j�E��_�'.n�� . . ' ' �� _. � � � � r � , , : "� - �,,.. . \.: .. � . ��-..j �_. . � . ,;�_._.. � . . . � - . - � � . �^=� __'--' ..._______�._._.._ _.��..._ - � -...i. �; __. -- __ .. � King County FI�E No.: 2009 0071 � --_ _ _ _ ___ ___ - -------- Depao�men� of Natura� ��our�ces ADDRESS:_____ 10046 21StAve. SW --- ___ -- --- __._--- � anc9 �apks NAME: S$uar4 Soules ��la#er ar��l L�nd Resou�ces �i�isiorn PHONE: 206.624.0740 ' � DATE OF INVESTIGATION: 1/21/2009 DRAINAGE IMVESTIG�►TIO�I R��FtT INVESTIGATED BY: Ted Chrisite FIELD INVESTIGATION � I arrived at the site of 15013 SE Jones Road 7:30 am to investigate a flooding cor�ap a1"int reported by Mr.Stuart Soules of the same address.I spoke with him via telephone.He stated that his property was high enough to only flood th�driveway but his neighbors yard 15005 was flooded up to floor level o0 the house.He stated that he and his neighbor share a culvert which does not allow for down slope drainage as it was installed in a reverse manner with the flow going up siope.He request my speaking with the occupant of 15059 SE Jones Rd.as he said she knew the history of the immediate area going back 50 years.I subsequently met with the occupant of this address,who identified herself as Liu Swenson.Ms.Swenson reitterated the statement of Mr. Soules,stating, when the new Elliot Bridge and Stewart Creek work was done,the constructors failed to put the levee back that the Army Corps had put in years ago along the north shore of the river.During this most recent storm event the river had rose up and flowed around a cotton tree(as identified) around her house and neighboring properties. Ms.Swenson stated that she is a�vaiting a FEMA buy out for her property and that neighboring properties have been bought and demolished.She stated that she is waiting for a better offer. According to IMAP records ihe area is in a Flood Way.The most recent flooding events indicated the water running consistent with this Flood Way indication of IMAP. This information is in this file. � z �� 15005 N � �� Shared Culvert � � ,�. \ �i. Ph to4 �/�/�"�� ' �-- -�� '�./,�// . ,.� !� �� . �� . � .; � � � .�` CEDAR� � '', RIVER � � i , � �' 15059 / �, ��---"Ph o � PhoEo � � � �Phato 5 " Photo 1� ' (� �' ulve COtfO�W00d Stewart Cr=ek .d�-�.,_ i (stated) former ACE Dyke Tree � `.�.._�.I_ �';) _._ � �.,- P`h o� �:- � �1—.:.,-,�T, `�� Elliot Bridge� noto a 154th Place SE Photo 3 �1G COU1e1TY WA�'��1�1Q1D I�AT�TID 12lES�UIt��I�I`4TYSION D�41NAC3E IN1fESTIGA�tON F��OR� . INVESTIGATION FZEQUEST _�:_PRosi�iti;::':; TANK IN RIVER � ;::Tjrpe`.:-::y�;:'::� (; RECEIVED BY: ��p �at�: o�i��tos o�c�d �y: File No 2��9-0653 -:.;::;.:_.._____ _ _ ;�--.-.T�— - - - ---- ----- - - --- ---- „_ .;.. ,;..:_. ,.: ...;,_:.-:.;-=;-._ --= - > - - -- -- - -- - - .° -� � ived=#'rom: ... ' ,_ .,..r.-..-�..�._ - _--: _ - - - _ _- - Re e _,.:,......:�;:-_ _ - -_- - - _ - _ _. c. -��: .. .. ,:._. -. _ _.._ _. _.. ... _.- --.._.., . ... - �e:i �....... ............_........_._.._...._...._............ ........._.._.-..._._...._........_....._.__.._...._..--...._._.___...��.......-_....v_........::.:_::.__::_...:.:._:.._:.:_.....� _:_:.�_:.�.:_..�..::.:'"'�:.:.:.:::^...:::::.:._:.:.�:^.c:::.__::.i:::i_'.!.... NAME: BILL.IE EMERSON PHONE: 206.561.3432 Other: Address: 'l5016 949 AVE SE Cify RENTON State � Zip 98058 -- _ __�._-:---:-�;,-::-. .----: -__,.:_=_-:_. Locat(on.:ofi.prablem,:;if;d ifferent:_ ...; :. ;__�.:_._�� .:...: -- _ . . _ _........ ..____..._....... _. . .. ---- ..._..... ... .............. AcC�s� Pel'rliiSsiot� Grat�tt2� Q� Ga11 Fir�# (Would Like To Be Called and/or Present} � REMARKS: � TANK IN FtIVER 1S EMMIT`fI1VG SOME SOR� OF FU1V]�S AND IS KILLING VEGETATION ,4B4VE. i ANK APPEARS TO �E SOME SORI'OF OLD WA"fER TANK. Rlat name: Lot No: Black No: � � . Other agencies involved: Na fieid investigation required ❑ _:� .:::::-:_:._::.=__::.-_..� �_=_:,.:.:. - .___.=�:..__ ,:::��-:::::::_:::. °:.=`::�� .: .::.';--:::��i=�=::��TO-�E.COMBLETED.BY,:EONC�l:A1N�::PROG.F�P.+M Sl'i4F� .:._.. . - =-:::-=-:_—::�-�:s�� ................. .... .. . ,- ..._.._�. � �/a NW S 23 T 23 R 5 � Parcel # 2323059133 Kroil: 816W TBros: 656J4 MD � 2 3 � Basin LCR Gouncil Dist 9 Charge #: - __, R��P�N$F,_. _ , ` _ � .. . _:< _. . , ._ - , .. ..:.-- -..,- . . ;. . _._..,_._.. . _,. _ _.._. ._: - ...... ... _ . ..._ . .. .:, Citizen notifi�d on: ❑ phone ❑ I�tfer ❑ in person ❑ er�ail :._._:�.:--,.�:-::�:::�:��::::.........�_,.._,.;::_��:,.,:�-.�:_;:_..._:�:-,� ,_ - - - _- - -- -- - - ---_ - - -- - ..._.. . _.__--_z,.� .. . ..... ...... .._.�___ ._.__v:.::-� ;.:..:�..��:_.:::_�_.::_=_ ..:..:�. .....:...�. ,_.__.._--- -..-- - ��.::,,=:: ��._�+..-__-,..c..... '. - __" _._... ._.::L._.�4:.:- __"..___c..-:^. — _ _ _ . -.a�....:._:_-:�:_:c•!-c:r:��::v_'_'_=' �:n..:_ ..._�._..� L_r.i::x�_.._�_-r}._.__._.__..�..__._..._":....... :.:�ra.._:r_�__.._:::::.::__:::�_�...c�z:_:�_-.:::�.ci=_^z?'_-..:c�_r.'::�e_:-c� =-. �c<::_:•' s__._••.�.-.• L..,__..=..�_,-_:::._..,. . '_r.....__-.._::::�r::::iT_;.s.. ...-_..._._....._-_".._.....__.._...._..____...__..._.._._._._.. _,.. .. .. . ..._.._..:.__-a�_.�._�.-._..._..'___-__-_..-_--�.._'___._......_._..._.�_ �._F.S.�.:...::_.:_ ..�.........._»."_'_.._.....„_ " . ....__._._..___..�_.-�.-._�__..-......�_....._.....__..'_`'_' � ' ."_"__.._.."'_.......""_ " . :�ISPOS:T.OIY.__.::�::>_=-:..�_-�.�r:...._.—_..__:.[�,..:,.__..__.----..._.__._.._.�,....�.._---..�.-_:::-•�-:-:_:._,:_-:a:;:::�.:;_�_::-:.:_::=-�:.__-:��.�..,,...._.........._....---.___�---- - , 1.1_ -..�.......... ��._,._ __ _ ..�...------.._..._._._.__.,.,..__...._...�.. .: - - . . ..._.__ .. .._.__.__.._.._..._...._ ... . . __ ..._.. . .__..._..._....__......---...........----�:�=.�--:�—�:-. � OR: No further action ' � Turned ta: on by recammended because: ❑ Lead agency has been natifed: � ❑ Problem has been corrected. ❑ No problem has been ❑ Prior investigation • identified. � addresses problem. S�e Fi�E# ❑ Private problem - NDAP will not consider because: ❑ Water oGiginates onsite and/or on neighboring parce�. � �� ❑ Location is outside WLRD Service Area. � � � Other{Specify}: � _ � . =;:�A��T�_C::L�?O.S,E�;;�: � `��B1��:; � � � � r ,:., , :,: ;; : . . . .. . ;: , :, .. ,:. : . ::: ..:..:.:..;�>: .:,.. ..:.: ;.. . ,.:� : . . �. ,:..� � `�}`� . _{:5�5 F '.. --: .",': "�'. ,.... . . . . . � T:�NK iN RIVER - 15��16 '149TH �,A�,VE S.E.. . r�� .::;:.:. '.F'j 3 �^. . � i a`t` 5.�. r. t. •.:�� .. ,.^ `' :_�. +�� .:r.. ,a .� e . • ,;. �. �� ' ,��,�,;1,*�� f�`��t � ..� ,�T� ��'��y�4 I �; {��5�.� !��a��,,,,�,""�,...��, �'�:-.r+r�.` . 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' , ' �Y � P' s:' � r :�;i �.Q. 131if1 �?' .,Y�6, 1 .,�i {Ct24�8kmqCounty �� •��G.::.._._::�' c `1k�:,- . • . . .r :� �The lnformaUon included.on,this map has bean compiled by King Count}r staff from a varlety of.sources and is subject to change without notice.King Couniy makes no representations or warranties,ezpress or implied,.as to ac�uracy,.complefeness;•timel(ness,o�rlghts to the use of such inforinat(on.Tltis docume�!Is noi(niended fof use as a survey product.King County shall not be liable for any general,specfal,indirect,incldental,or cdnsequonEial damages includEng,but not limited to,lost revenues or lost profits resulting from the use or misuse af the � K�� D�nt information.contained on this map.Any sale of this map oi informatloo on th[s map is prohi6ited except by wriElen permission of King County. � y Date:7I14l2069`:��'�;Source:King..County iMAP�=.Stormwat8r(fiftp:]/www.metrokc:gov/GIS/iMAP)•�•'.` ` . 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"�. .r.:......F� �':i: :_..� � � ... ..:........ .. . .�. ddW�.� 33S, . ��,`'� � ' , o��'r�i�i4 , ;��:. , . : , . , ,,. ..; . . 200��0700 Brent �a�r9ey Site Vi�it �hotograp�� KeithDougherty D�C�mber 5, 200� January 13, 2009 TO: File FRONI:Keith Dougherty RE: 2008-0700 Brent Cawlev BACI�GROUND' � FACn.ITY: DR0535—Nladsen Creek Overflow Channel The facility is located in Renton north of SE Renton Maple Valley Road between 149th Ave SE and 154th Place SE. There was no letter of formal acceptance of the facility,�but it appears it was required from a lawsuit judgment in 1974. The facility file states that Brent Cawley would like a hydraulic evaluation performed to determine if realigning the outlet culverts to be almost parallel to the flow of the Cedar River would increase the capacity of the bypass channel and prevent it from overtopping on to his property. His property is located just east of the overflow channel along the Cedar River(parcel 232�059123) Mr. Ca`vley has complained of trouble in the past with the facility. He stated that during the big storm of 2006,he had a significant amount of water flowing through his yard towards the Elliot Bridge Levy. He had also stated that he had dropped a leaf at the end of the pipes that convey water from the overflow channel to the Cedar River. According the Mr. Cawley,the leaf flowed backwards up the pipe rather than downstream in the river. He also dropped a leaf at the inlet of the pipe and said it did not move. 1�1r. Cawley has some engineering background and suggested to Rick Lowthian that the behavior of the leaf may possibly be due to a Venturi effect created by the river and the angle of the pipes inletting to the Cedar River. He would like an analysis done to determine if changing the angle of the pipes outlet to the river would reduce the head within the channel. His belief is that there is a drop in pressure at the outlet of the pipes and that because of this drop,water is being pushed up the pipe, or it is not allowing water to flow freely out of the pipes into the Cedar River. He thinks that changing the direction of the pipes (angling them more downstream,parallel to the river versus nearly perpendicular)may allow the water to flow freely from the pipes to the river and may even provide a suction action that would draw water out of the pipes. He believes the change would increase the capacity of the overflow channel and potentially prevent�vater from overflowing on to his property from the overflo�v channel. INVESTIGATION: ' 2008��t0� �ren� �awley �ite Visit Phot�g�aphs � KeithDougherty December 5, 200� Initially I was asked to review the Venturi effect to determine how it applies to the overflow channel entering the Cedar River. The Venturi effect is used to determine.the change in pressure as an incompressible liquid flows through a constriction (usually in a pipe). Most often the Venturi effect appears to be applied to pressurized pipes with bend angles constricting the flow within system. The similaxity could be made to the inlet pipes of the overflow channel acting as a constriction to the flow of the Cedar River. While the pipes of the inlet channel may act as a constriction to the flow of the river, it would seem reasonable that the effects of the pipes would be minor considering the size of the river versus the size of the pipes and how far the pipes extend into the river. Currently, I do not have access to any models to simulate the Venturi effect. As such, my investigation utilizes the stormwater models and information available to me. A quick document search on the properties near the channel showed no easements or tracts that define the drainage channel. It was observed on the Quarter Section map - however that nearly the entire channel lies within the 100-yr flood plain. Mr. Ca�vley's � property is also within the Cedar River flood-way. The areas adjacent to the Cedar River at this location are protected from flooding by the Elliot Bridge Levy. Investigation of the DR facility file found that this channel has a lengthy past. It was originally constructed in the mid seventies as a result of a lawsuit in 1974 regarding increased runoff from the Fairfield development. At that time it appears that easements were obtained from at least 2 property owners by King County to maintain the channel. There have been several complaints/lawsuits following the original ruling as it appears this channel has had many instarices of flooding. More issues arose when WSDOT widened highway 169. At that time,they replaced the three 36-inch culverts across Hwy 169 with a single 8-foot by 6-foot box culvert. Based on simple calculations, it would appear that the box culvert has more capacity than the three 36-inch pipes. The additional capacity would indicate the potential for increased flows to a channel that already has a history of problems. I did not find any documents of a redesign of the channel at the time of the culvert replacement. Brian Sleight and I visited the site on December 5, 2008. i�1x. Cawley met us at on site ' , � and showed us the pipes of concern. He stated that he had seen the pipes running within 6-inches of full. He also explained that during the large 2006 storm that a significant amount of water was running through his yard. He stated that King County maintenance/roads came out and added some fill to the berm on the east side of the channel to reduce some of the water flowing through his property. He also believes that the west side of the channel is higher than the east side and would like them to be equal 200�-0700 �rent Ca�vley �ite Vi�i� Photographs KeithDougherty December 5, 200� (if not higher on the east side to prevent flows onto his property). Brian Sleight and I surveyed numerous points on the site. For more information about the survey,please se� __ _ __.__ __... ---- --._._. ----. the attached exhibit and summary table.; _ _ _.. _ __ _. 4 The analysis of the data involves several tasks. The primary task is the hydraulic analysis �n the pipes and the different pipe discharge angles. Additional ta.sks include: • Betermining if the east bank is lower than the west bank. 4 • Comparing the elevations of Mr. Cawley's property to the elevations of the channel and riverbank. � Determining the Cedar River influence versus the Madsen Creek influence on 4 flooding conditions. The hydraulic analysis was performed using the King County Backwater Program (KCB��hich models storm flows through channels and pipes. Background data was taken from several sources including the Madsen Creek Flood Plain Study performed for the Renton Assembly of God development and the WSDOT expansion of Highway 169. Additional numbers had to be determined or assumed before the hydraulic modeling could be performed. These numbers included: the tailwater elevation(96.Oft)which was based on descriptions/observations made by Mr. Cawley. �The slope of the channel , (between 0.23-0.44%), the slope of the pipes (approxirnately 1.0%)based on survey data, the Cedar River flow volume (�4800cfs) from Cedar River report and velocity of the ; flows entering the pipes from upstream (7.89ftlsec)based on the cross-section if the channel, the flows into the channel from upstream(261 cfs) from the Madsen Creek Flood Plain Study. Additionally, a range of flows was used to understand��here flooding may occur at different levels. For the analysis, a range of 50-450cfs was used as a range of the channel running full with no tailwater elevation(�SOcfs) and the two 6ft pipes flowing at near capacity(�450cfs). Lastly, several angles were used to simulate the changes in alignment as Mr. Cawley requested. Four bend angles of 0, 30, 60 and 90 degrees were compared to determine how a change in pipe alignment would affect the water level within the pipes/channel. Note also that all elevations are relative elevations from the survey data,not actual elevations based upon a NAVD datum. RESULTS' 4 The modeling of the conveyance in KCB�� shows that there is not a significant change in water levels by changing the discharge angle of the pipes. Assuming a conservative scenario where 261cfs is coming into the two 6ft pipes,there would be approximately 130+cfs per pipe. The difference in elevation from 0 degrees to 90 degrees is only about 0.2ft{�2.Sinches). A more severe case where a11261cfs was modeled flowing through a � ��'r. ..... . . . � 2005-0700 �rent CavuOey Site 1li�it Photograph� KeithDougherty December 5� 200� single 6ft pipe.shows a change in head of less than 0.69ft(�8inches). As mentioned w before, the range of flows up to 450cfs was modeled which is much higher than expected. That data shows that a single 6ft pipe with 450cfs of flow would be in overflow conditions, but it would still only change the water level approximately 1.Sft. These '� results indicated that there would not be a significant gain to the water level if the pipes were realigned. � � � 4 A comparison of the survey points from the west bank and east bank shows varying results. For roughly the southern 400ft of the channel,the west bank is lower than the east bank. For approximately the northern 400ft of the channel,the west bank is higher � than the east bank. This is the area more closely located near the Cawley residence. Other than a low spot in the channel's bank near Mr. Cawley's driveway, both banks along the northern 400ft generally have less than 1-foot difference in elevation. 4 The elevations of the overflow channel's east bank and the elevation of points near the Cawley home, driveway and well-house then compared. The elevations of the east bank are generally higher than the elevations of the Cawley property indicating that water will flow towards their property if it overflows the east bank. The low point of the east bank (97.62ft) is lower than the house foundation(98.25ft)and the well house base (97.77ft) but it was higher than the driveway spot shot(97.54). The approximate low point on the Elliot Bridge Levy at Mr. Cawley's property was also found to be at 97.49ft. This is slightly lower(�1.Sinches) than the low point along the east bank. Aside from comparing the low points of the east bank and the levy,the other elevation shots taken along the levy are generally lower than the elevations along the east bank of the channel. This would indicate that water is more likely to come from the levy overflowing before the east bank of the overflow channel. This is consistent with conversations with Mr. Cawley in January of 2009. I called Mr. Cawley on January 21, 2009 to find out if he had any flooding issues due to the storms over the week of 1/5-1/9. Mr. Cawley indicated during the phone call that he had significant flooding (within 4-inches of this floor) but most of it was coming from the river's berm at the north side of his properry, not the overflow channel. He also indicated that if there was water coming from the Fairmont development,that the channel would not have been able to handle the flows. However, other than the low spot elevation,the levy elevation is lower than and very near the elevation(within one inch} of the house foundation. It should also be noted that the elevation of the Cawley foundation is between 1-2ft above the tailwater of the river when it is running at the high levels reported by I��I�. Cati�vley. OLastly a comparison was perfonned to determine the influence of the 1�ladsen Creek overflow versus the Cedar River impact on the water level in the channel. Again, data for i � -� _ ._�� 200�-0700 Brer�t Cawley Site �Oisit Photograpf�s Keith Dougherty De��mber �, 200� the culverts as well as the channel were analyzed in the KCBW program. The low elevation taken at the bottom of the channel(while dry}was at 9234ft. During the storms in January,Mr. Cawley indicated that water was overflowing from the Elliot > Bridge Levy at the north of his property,which has a low elevation of 97.49ft. That means the tailwater elevation in the channel at that time would also be at least 97.49ft indicating that the river's influence on the water level may vary as much as S.15ft or more. Using the 97.49ft as a tailwater elevation is a conservative scenario to model the channeUculverts to determine the influence of the 261 cfs coming from the Madsen overflow. That modeling shows that the water level in the overflow channel would only � rise to 98.33ft which is a difference of 0.84ft. The results indicate that the Cedar River's tailwater elevation has a more significant impact on the water level than the flow entering the overflow channel and the capacity of the channel or the culverts. DISCUSSI011`TT' Several factors were considered when analyzing the flooding issues at Mr. Cawley's property. The main task was to perform a hydraulic analysis to determine if changing the pipes angles inletting to the Cedar River would improve their performance and decrease flooding from the overflow channel onto Mr. Cawley's property. Other factors considered were the overflow channel's east and west bank elevations relative fo each other, the elevation of Mr. Cawley's property relative to the channel and the river elevations, and the effect of the rivcr versus the inflow to the channel on flooding conditions. The results of the hydraulic analysis on changing the pipe angles indicates that only a slight improvement(0.2ft or 2.Sinches)may result by altering the pipe alignments as they � inlet to the Cedar River. The elevations of the east and west banks vary based on location. Over the southern half of the channel,the west bank is lower than the east bank. But the northern portion of the channel, closer to Mr. Cawley's home and driveway, does show that the eastern bank is lower thank the western bank. At the low point in the east bank, it is almost 2ft lotiver than the west bank. The relative elevation of Mr. Cawley's property to the overflow channel and the Elliot _ Bridge Levy does indicate that his property will receive water that overflows either the east bank of the channel or the levy. The elevation of the Cedar River when it is running. at a high level indicates that flooding in the areas around the river would not be unusual during times of high flo��s in the river. Additionally,the Cawley property lies within the . • 9 200�-0700 �rent �a�vley Si�e �di�it Phot�graph� ICeithDougherty December 5, �o�� 100-yr flood plain and the Cedar River flood-way, which is an indication that-flooding during large storm events is not uncommon and may be an ongoing issue. Lastly, the impact of the Cedar R.iver's water level seems to be a more significant influence on water overtopping the east bank of the channel rather than the upstream flows from the Madsen Creek overflow. That would lead to the conclusion that the flooding is less likely a capacity issue and more likely a result of a high tailwater condition from the river. In short, it appears that the issues are more likely related to the water level in the Cedar River and the elevations of the overflo�v channel and Elliot Bridge Levy and less dependant on the angle of the pipes inletting to the river. Reviewing the data shows that at an elevation of 98.Sft, flows that exceed the expected maximum 261cfs from the Madsen Creek overflow can be conveyed without flooding through the channel. The approximate amount of material needed to bring the low areas of the east bank up to 98.Sft is about 22 cubic-yards of fill. This would likely cost less than$1,000 based on the NDAP Construction spreadsheet. This would seem to be a more suitable and cost effective solution versus changing the pipe alignment and performing work along the Cedar River. RE COMIVIENDATION' I recommend raising the low areas along the overflow channel's east bank to the relative elevation of 98.Sft according to our survey data. This would be a more effective solution because the results show that flooding is more likely a result of the Cedar River water level and the elevations of the banks rather than an issue caused by the angle of the inlet pipes. It is also a more cost effective solution and could be implemented more quickly and with less impact to the Cedar River. � � 200�-�700 �rent Cawley Site Vo�it Phot�graph� KeithDougherly D�C�mb�r 5' 20�� ..._._. � �� 3��t��„��,:t� �6'�i ___ ,��{�Z) 7 =r Y �/• � ��: �SHE F Of3yl�ENhtFE�i� � � a`- �, f a.t'' �� r, �"'�� .� . ✓,� �:1 . . . . , �' '� � � , - x�',��j`� ,� , �i''"�� ^� .�X �. . {HYDR) .! ' -- i f d f,. i: �� . 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F.3 ;� t4t9p *;' � � a., ;_ �,'+i �- � �j •+t �� '�JI'-��A '�, � y}",f j. � �1 -= <+�T _ I t ` �M�� , � �="'-i.b �` ` X � , � � i � ,�"r�`' (�I�!�,�� ,�_��a1�6�:(9�127� _: � � j '�, =�� .� ��o� �� ,� Box Cu1Vert Inl � F '� � FRENgCH D .� �i07��,� - � �:��,ER L�_�I'OII1N13dSCII �,�� b258� � �� f�9158); Creek Overflo�; � � ' t-..s1?� ..t _ �T.._nE � �c... , . : t �j�f� r f, r � ,` xt' 4 - �� ,152s7(91LBj �i; r-t!/!�� f y� r.�'� , � lrr�; � ,. � /X f�, r � r�Fy��f,��= ��N9 t9fl�$) � /.��l1,�f�r��ro1A�/�/r`., '/�;�z,��;, ' / ��jfR��{`�� f��j .� f� ' I . , ,- �� / '__� � �� ` � `�J r ' I ,r� 1.f F.J�. •� t . � Y � ��1.��{ttr� �-.�!� Ifif��_�_. .,t �1� 'r,_'�_��t✓_� i:_ I Aerial view of the channel and Brent Cawley's properiy. The Cawley properiy is outlined above in red. The channel runs the full length from the highway to the Cedar River is outlined in blue. , � ,— . ��IG COiJI+1'�Y�A'Y'�R�I�TD�AND�ESOL'1'�..CES I�IVISAOl<I � �R�II�TAGE Ila1�EST'��'TIOl�t�P�IaT INVESTIGATION REQUEST r•. 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FALLEN TREE s �-:�=..:;�_� .. .a:. � _�•_:� � ,.. , �.:-, ..., .:. :=.�;__. �,-:� -- --� _,7:�,;= ..:.� . _.� �.,::::��::�:::�:::........a..:.. ,::::.�.:. ..:._ -.,...._.� _.,..:.._.�;:,: .::.,..._.....��::::.::._. � RECENED BY: Wlcp Date: Q9f09/08 OK'd by: Fi1e No. 20��-0507 ...._...__.._._.. ...,.:.,.�:.-w.,:::.�,�.,,�::�,�.—,:.:,�:,,::,:.�:....__......_........_.._..__..:�--::�-�•.�.�•:::,..,:::::�.::::�.;<.:. ...._.._................::::_._ __......._.._....::_-:::�......._....._. :=<._... - - _-- - - ......_.:::-- .s._ ._ ....�._:,;:.,...._......_... ._...___ ..__..._..........__...._::�•:=�::��.__..��.. ........_,::�_.:--::_ :::�...�,,::�_ - - - - ..._ . . ..� . ..._ . .._. _._..__�s ._........._,..._. . . ...._..-:-.r.;.._...._._:r.::�_:..,.:_ .. -._..:c .. .L r.°:a:.r-::::->:�::a_•_-::c•_-c:Cr.e:�tE::::�ii::;::a:a�:�r.n��:_i:?:�iF_59 .... _..v..__..e.i .... .... .a.. , . . ......._a.av...__..-a......4......_......��..::r_.::�r.---.,°..a,_..i...i....r..n::��..._,............za:.:m:c'4�'4r.:� ..... ..... . .x...... ._... .. ' _ " _ ... .. .._ r- '"....................i....._.......i..._..s.-_..=:. � ..._. ....�, r_...._.........._..,-_...:�i........-�ex r.•r::;:_��•�::c:::::i-�;�1ic�x:':-'c ..... .... .... . ...»... ... .......�' . ":•::::i ..............._..�..._..._�_.._.... .. ...�..at_...1.Y..�.... ,.....�._.,............ r ...:`:?�>> � - _ .I ............,...............:�:-�::.::� :.:::.. . :. ... .... ... .:.... ._.s_i._ .. _'-.._....-,._...._....i._r.i.....e_._...___..-._.........,,.,..._......._ ._ "r_..._..,......_..:.:.. .�i.._...3�--._...�..inF.!•:_��mn,r..::�^�a::s.::::ia::aY�iEe2:i:r� ' __ .._....i.............._:-:2_"i:?i:iiii° ... . � . �...a��.�.._....._.....s....�._�__..___ .;.�......___.._�..�:..��.. _.. ,::::- - .�4�_..._...__... �.t. ;_.... _,.__..�.__...�:�:�,:..,:�•: - - -- _- - - __.. .. .�.____.�.._...._.._.._....�.,_.. _......__.._..___....._ ....,........ .� ..........,_,.._... ..�.�„.. .... - - ......_.....__.._.�....._.._.�._...._.__..o...........__i....._.....�......rrn•,-,::e�._..�._.._._..___E.._......�__:___.____.._-��...-•_:.__c_:l .............s . 4=F. 6:x.n�t.'r::�..�..�.:::l:::ae':.,._. ..- �-..,..__.....-_._...-......_t ,,.�......,._.........»....-.+.,_.__�:, ., �.:•."'e'"..._......_;._.:.:.x.: �..t::......... ... .._ ..:.-_•.::::• NA�: BRENT CAWLEY Pxo1vE#: 42�,761.4170 Other#: 425.965.5885 Address: 15247 150TH LANE SE City REN'Tl'ON State Zip 98058 : = :_ - _ . , : : _ � . _ _ _ - _ _- . .........:.::�:. ��..��ta� xQi�Z�� a :d�: ��.ti �� .��A��' ...,.�'�.�._.��..�'�.�-��`��1�T� ��'::��'�-_��:;......- ..............#:......._..._,__.............. ._.._...�...__�'..._..-.-.. __::.:_. ......._:.�..N... _._�.,. .. ._...........___.___�._n,�_,.,�..,......_...�......_...._..------_.___.......__...__.---- _-._ ......__..... ._._.....------....__..._---�-------_---._ .z_._., . _..., ....,.........----___-__�., , � _�..,..: _ ...,�,__-- -.-,--.-..- Access Permission G'ranted � Call FiYst (ti�Tould Like To Be Called and/or Present) � RENfARKS As of Sept 6th 2408�a freshiy fal(en tree has blacked the river just 2 feefi down stream of the Madsen creek bypass drainage culverts. This end af the tree is aiready catching!stopping debris coming down the rlver, and will eventually dam up and cause further back up af the Madsen creek by-pass during the rainy season. The Madsen creek by-pass aiready does not have enough fiow capacity to . handle the vo[ume of water required during the rainy season. The current inadequate design has already repeatedly flooded my property causing damage. Any further impedance wil( only increase flood damage on my property that runs adjacent to Madsen creek by-pass. Please have somebody remQve the tree in question. Plat name: Lot No: Block No: Other agencies involved: ' . No fieId investigation required ❑ -�-�----. ��............ .. .... ..._ _ ........_::: , ..............._... _........•--::....._:.::_,::�..,.::.:.._..:.:....,.:_:::::::_::.::.�::: -,.., , - - .......��:_.. �.x_:��.�:�:,;_:;_�::.:;:.��::=�::::.:::�:;:�:�:::,::::_��:�::._:::::�:.:..�:-.�<::::::::;:;::::::::::_:: :�:�.-:a:_._:a..,._ .i�.yc_+�wn�-.��.r.rr,,.-...-?_.�a�y:a-:...:.::�_t-;E::^:.^:::r._::,.i�c.� i_._......r..,-----....__�;.:..:.:':;-:::................ . �.. - .. .. . ., . . .�- ..=4:-a�:•:::•- - - ........ �..,i�xS�x�.._2_..�z.�'�_._...._....... .. _ _ ..I�....� : _�:: . . . . .. �.: ...,.. : : .: �.. .•• s .: '� : - ' _ '_`rF=a��•3::ii�_�v._=::i:::i�iiE=�:: it:iE�-.»-31a-.—�.?=.-a...._�o.....__..n:r.—_t..�;.;4�......._.......J.. ,..... . .._.:. ... : .. . ..... ...... ...... .....-. .. .� . . . . .: •. � '" .ys�......i...a.-...._.�..—:....,...,_ ...z _�....,�_.... ... �....,:�•,�r_::::�:,.,... ...Q_ �L�R$...... �1�fP..Lr.iI�':� :�t�:[`+..�:��s:'•��:;;:::�;=;;;;;-;��.;':��z:_..,......�......_....... �_-_,.,:.:�, rT.._8��? 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'_ ' � L.—,. ..-....l...._.__._..___, .-. .�.t''...: .'_ ' _ �..v.._....:.:-_ -_..-....__�._u..... .......... .. ...n.. __.,.. .- -^ .........._....:.._ . Citizen notified on ❑ phone ❑ letter ❑ in person ❑ email E. �.� j� �^ �C. Z�� -f%��c� _....___. «:�.:, .....::......_...._..z.:.:..._._,...:_.,.�._:�..:�:_.:�,��.:�=,_.:.:... .__:;:�- -- - - ,�_.,.�:.. .. . .�..__w..:.::::�:::�:.. ....... ,.._��-:�_v ...._ . ._ ....,. �....:::_.�::::;:: _. ,,.;._-=._:.�..; ....._.,.,:�:�. .��,.._...,...�...� .�...�.::�x��,:�:_�:::::u:,� _... . �_.�._�, �__.___ ...::.:............__....:.::.. _.�.�__._..... __..,._...�........._�_...,_., -._�,:::::::_:�:_..::�:�:._:::��.��_.:.::.::..:::=:_:;�:_:::��::_:::;.;::::::_.�.:�:_::�,:::::.::::::;;.,:_:.::-::.:::::._:; __ , --.__.__.--,,:�_�,._,::.__��M��:��z��_<<_:�.�:,.:,�:�_._w:.=__�r_�_:::� __..�,:� ,; . ---.___.__... ,- ,_ ..._._..__� �._�.__.._. :;�,_ - - - - - -- -,:t..� __., �, . . ._.__..._,.._._.,.:_,�:: _.,_ _..___ �—::_�..__ ---�,»�..... _ - - -- - .�--. .� ,�.. ---_-- ��::u-:::,:: •--�___,�:;�:::_�. ,:.:�,..;:,:�:..�.: , , ,...�::.:.�..:.T-:::..� -. . ... ._..._...... _ ..-.:_:::::.: ._.. ..:-.::.._..:::::::...:.::.-::::::..... �+�.��f'•� --�� Ir 5.._.__._... � � �- �- a �. � �� -r + - �..� f OR: No further action Tur.ned to; on by recommended because: ❑Lead agency has been notified: ❑Prablem has been corrected. []No problem has been ❑Prior investigation identified. addresses problem: 5EE F1�C# ❑Private problem-NDAP will not consider because: ❑ Water originates onsite andlor on neighboring parcel. []Location is outside`;TL,RD Service Area. ❑Other(Specify}: _... ... ., ) };,�,ti„ �r f `;DA�fi::;+��(3��y��i �. ��r�% / 1/ =:'�3:".�-�'�'=� � � `-- . ��..___.�.:.,__ .. .. __...._�.:. / �r�::�!ek.�t� ... ..__ J r z , . . .........:...:..�....::;.:..::... ..... ...::::: � I�rG Cotrrot��Arr�L�;��a��i��a�l�; . I�RAIIVA��.�:I1�I�E�fi��TI(��?I��'��"�" � ` �� ,r� � : ��.INV�STIG[�TIONR�QTJ�ST i Yp� � � � - P�osr.��: �f ' � � � /� `� ' '� � � . ' �� RECEIVED BY: ( ��:'•:Date:::;�_�� vOK,d:bti. `��P�.Q,� .�-�a� � Received from: `; �- __ . _,,/ � ` � � „ . �'; . a � �� e � (D x) '�� (L }. �•_.. }) / --? NA��: .�� : P�toivE �G�� '��i� �,,' i f ��3�� , �,., :. : ,...:: � ; � _;�g�r-:.;� � - � �:� �' C�tv' G/' �: �tate 7ip F` r� ADDREss: !��.f'� 7 %� � �!. �,L� . i� .�:�C�� -�:� ..�z.� � . .. ... .... ....:,..:,:...:......,...... .. ... . . .._ . ... ��... :.:�.....�.:......:..:.:�.�>-:.:: ;..: , ; ; ; LOCATION OF PROBLEI�E,IFDIFFERENT::.:`::::�:�`•'�.`.;:;:: ;.:;:.. :::_`;;,::::. ' - '+. Access Permission Gpanted �:.�.:._.`�'CalltFiXst;(��ou1d Like To Be Fresent} � ;; r J�� , r�/./.�' � x' . . . .. . . ��1 �� f '��_if/�.� �(f`�f�l!��/' •v .. �� //��. ��.�� 4. � �,�:��:��= � �:�:: ` � � .; ;� �..� C,�.1�2�J/],/� � •. .,:. r L!.�ll � �'�� / f ff �� .., , ..{ �� / � ��f�// e'��.�� J �W,. :'•:/.••, �,(��f. ��`i � ��, ��i��... �� .'<�. y�; _s�.-' �/.%��.2/�,( �� ` .� �� ..'.;';�.:;.: ::.`. :, C��.��...� �:/'c�.� �'�;��/'%!�1y'�%'': - ; z. � .. . .. ........: , ,/� � l�� .�:,: .,� : �:�� ,f � �� /�' ? C�� v�-� ��, �, -2`�� ..P�..�'1� �,�'�'._./'�'� �:i� ¢. �,� � � � � ....:..:, �'- ��_/�''.��: � .�'' ��'�:��./..��'��,� >. - ��/ . � - �, � 1��:��`�:� - : � ' �:�,�: _ Plat natne: �� . . .:...........: g �f Lof vo: � Block 1_�o .. ...� . ... , .. _�e�(',:--��:��',� ... . � :: �. ;��.��.::.. _ . ' ' Other ageneies invol��ed: No�eld in��ti;atio�a re�uir�� .-�� - - �,_T -�o��'co�It>i�,z i�i��-cotii��.:��r��o�iii�f s r+ r = - , _ - �.�.� ...'�. . � �' . �� ; � �� ,�- ..R � � � � ��Kroll°�� Th`.Bros: �le`�._' �� ^f %4 S � T R .'.� Fazc�l No � � � ��,� � � . ..� : _ ��. .:..;. ;:.:,::;:�:�. - RDP Basin ��' �Counci�D�strict � Ci Charae Na. .: . . .: ....... �. ---�-... . �' RESPONSE: Ci#izen notifiect�ori °�. ;::.: �'.:'.::�:' . ` by�/ pl�one letter 'L�person - ��'��' ,��n ! ��+iry'Z��: � r�3"::`' :r!-..m. ra� To �7�.j �r -,��' ��.�a� ��' J ! � �.. :�:�: - `i . �.:��=.:..:�� - �y �� _ �. ..�� :�::��::�::�z�� _ s . ....:..... ::. . i�l,,:•i•� - - DTSPO5TTION: � Turned to : ��o�z:��'�,`��`�`��::° / �:by OR :Na fiirrtl�er acti�n reccnunende� hecause.: '' Lead agency has bean notif�ed°::.�:..`.�,'°��;�. ' ; . - � Problem has been corrected.:� .�.';'� I�a probleiim has t�eezi rdenti�ed Prior in�estigatic�n addre";e� �r�L lem: . � SEE.FTL�� Private groblem-ND;AP will not corisider because Water originafes�oiisite�aii�/or::on ne�ghbo�ixi�parcel ;.', . ' � � Otiier(S�eci�): ,; DATE CLOSED: � / �u ( ��:. ...: ��;;��..:....::..-�..: .r,�.�t::;s::. - . � .� . .... �. . .... ... .. .. .. . ,. ` .�