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Home My WebLink About03232 - Technical Information Report - Drainage 3 THE RESERVE AT STONEHAVEN Storm Drainage Report Prepared for Westcott Homes April 25, 2005 !, � THE BLUE LINE � 25 CENTRAL W4Y . SUITE 400 • KIRKLANO . WA 9B033 G R O U P T: 425.27 6.4051 • F: 4Z6.21 6.4052 WWW.THESLiJELINEBROLIr.COM 3 232 THE RESERVE AT STDNEHAVEN City of Renton, Washington Storm Drainage Report Prepared for Westcott Homes 10519 20�h Street SE, Suite 1 Everett, WA 98205 Prepared January 21 , 2005 Revised March 9, 2005 Revised April 25, 2005 Blueline Job No. 04-082 q� S. D og w�.s�0 _� a�, �y = x Prepared by Ben T. Rutkowski �� v �GI STE4Q Reviewed by oN�►�-ti��' Brian J. Darrow, PE IXPIRES 5/05/G�i -� IBLUE LINE The Reserve at Stonehaven Storm Drainage Report Table of Contents SECTION 1 PROJECT OVERVIEW.......................................................................................1-1 SECTION 2 OFFSITE ANALYSIS...........................................................................................2-1 SECTION 3 DETENTION AND WATER QUALITY DESIGN .................................................3-1 DESIGNSTANDARDS....................................................................................................................3-1 EXISTINGSITE.............................................................................................................................3-2 DEVELOPEDSITE.........................................................................................................................3-3 LEVELPOOL ROUTING.................................................................................................................3-4 EMERGENCYOVERFLOW.............................................................................................................3-7 WATER QUALITY ANALYSIS AND DESIGN....................................................................................3-1 O SECTION 4 CONVEYANCE SYSTEM ANALYSIS AND DESIGN.........................................4-1 ONSITEPIPE SYSTEM..................................................................................................................4-1 OFFSITE DRAINAGE.............................. .................4-4 ...................................................................... SECTION 5 TESC ANALYSIS AND DESIGN.........................................................................5-1 Appendix • Existing Conditions Exhibit • Developed Conditions Exhibit • Catch Basin Tributary Areas Exhibit • StormShed Modeling • KCBW Output � Preliminary Storm Drainage Report prepared by Core Design, Inc. • Excerpt from Talbot Ridge Storm Drainage Report prepared Triad Associates Ie�uE L I N E � ' The Reserve at Stonehaven Storm Drainage Report SECTION 1 Prolect Overview The proposed project is two parcels totaling 5.95 acres. The parcels are located at 4801 Main Avenue South (parcel #3223059022) and 4815 Main Avenue South (parcel #3223059096) in Renton, Washington. More generally, the site is located in Section 32, Township 23 North, Range 5 East, W.M. in King County. Please see the Vicinity Map be I ow. v,�._�t� j �' i I �'r!EDICAL SE CARR PD I �I CEN TER 11 , ' i , � i � S 4��,�' i i S 47�N �T ' � SE 184 TH PL ' �� %85TH PL �---�I � S� ,pE r F, S/TE ' � � j � o sc �c�7Ta P� o i� 2 � ' � � � � Ti � � �I � 4� � O � _ y I � � a � � I � � - ?92�b'G rL � � I �� '��'� �= i Vicinitv Map Not to ScaJe The applicant is proposing to create 36 lots for the construction of single family residences. Please reference the Developed Conditions Exhibit included in the appendix. The onsite runoff will be detained in a combined detention/wetpond. The detention/wetpond has been sized according to the 1990 King County Surface Water Design Manual (KCSWDM). The interior features of the pond are designed according to the 1998 KCSWDM. #04-082 I B L U E 1-1 LINE King County Department of Development and.Environmenta!Services TECHNICAL INFORMATlON REPORT (TIR} WORKSHEET Part 1 PROJECT 01NNER AND ' _ Part2 PROJECT LOCATION AND , PROJECT ENGWEER . DESCRIPTIQN ' 'I _ , - . , , ..: , _ , . _ , ; Project Owner Project Name ' Westcott Homes The Reserve at Stonehaven Address Location 10519 20th St SE.Suite 1,Everett.WA 98205 Township 23 N Phone (425)397-8070 Range 5 E • Project Engineer ��••••�••��•Sectian 32 Brian Darrow,PE COI71P3�y The Blueline Group Address/Phone I425)216-4051 Part`3 TYPE OF PERMlT. ; ; � , APFLICATfON � `: _ Part 4 OTHER REVIEWS.AND PERMITS Subdivison DFW HPA Shoreline Management Short Subdivision COE 404 x Rockery Grading DOE Dam Safety Structural Vaults Commercial FEMA Floodplain Other x Other Construction Permit � COE We�lancls � Part 5' SITE COti1MUNITY AND,DRAINAGE BASIN - Community Soos Creek . Qrainage Basin Green River!Black Riversub-basin , , Part 6 SfTE CHAR'ACTERISTICS - River Floodplain Wetlands Yes ' Stream ' Seeps/Springs Critical Stream Reach High Groundwater Table Depressions/Swales Groundwater Recharge Lake Other Steep Slopes ', ,Rart 7 .SOILS.: , � _ Soil Type Slopes Erosion Potential Erosive Velcoties Alderwood 6-15% Moderate Additional Sheets Attached .Pad 8 DEVELOPMENT LIMfTATiONS REFERENCE LIMITATION/S1TE CONSTRAINT Ch. 4— Downstream Analvsis None Additionaf Sheets Attached Part 9 ESC REQUJREMENTS : - MfN1MUM ESC REQUIREMENTS MfNiMUM ESC REQUfREMENTS DURING CONSTRUCTfON AFTER CONSTRUCTION X Sedimentation Facilities x Stabifize Exposed Surface ', x Stabilized Construction Ertrance x Remove and Restore Terrtporary ESC Facilities x Perimeter Runof;Control X Clean and Remove All Sift and Debris X Clearing and Graing Restrictions X Ensure Operation of Permanent Facilities x Cover Practices x Flag Limits of SAO and open space I x Construction Sequence preservation areas . Other Other i ' I . . i _ :, •Part 10 ; SURFACE WATER SYSTEM: . � Grass Lined Tank Infiltration Method of Analysis x Channel ssuH Vault Depression x Pipe System Compensation/Mitigati Energy Dissapator Flow Dispersal on of Eliminated Site ,c Open Channe! Storage Wetfand Waiver x Dry Pond Stream Region�l � x Wet Pond Detention Srief Description of System Operation P�Pe and catch basin system to onsite detention f water quality pond Facility Related Site Limitations � Reference Facility Limitation ', II Part 1t STRUCT:t1RAL'ANALYSIS Part 72 EASEMENTS/TRACTS � Cast in Place Vault Drainage Easement Retaining Wall Access Easement X Rockery> 4' High x Native Gravrth Protection Easement : ' Structural on Steep Slope X Tract '� Other Other II . _ _ . _ _ : , i, � Part 13 SIGNATURE OF PROFESSIONAL ENGINEER ! I or a civil engineer under my supervision my supervision have visifed the site. Actual site conditions as observed were incorporated into this worksheet and the attachments. To the best of my knowledge the information provided here is accurate. Sioned/Date The Reserve at Stonehaven Storm Drainage Report SECTION 2 Offsite Analysis An offsite analysis was conducted by Core Design, Inc. as part of a Preliminary Storm Drainage Report dated January 2004 and is included in the Appendix. #04-082 I B�u E 2-1 LINE The Reserve at Stonehaven Storm Drainage Report SECTION 3 Detention and Water Qualitv Desiqn DESIGN STANDARDS The detention calculations were performed using Engenious System's Inc. computer program StormShed. The detention volume was designed according to City of Renton standards, which reference the 1990 King County Surface Water Design Manual (KCSWDM). The 1990 KCSWDM requires the peak runoff rates for the developed site to be equal to or less than the peak runoff rates for the predeveloped site for the 2, 10 and 100-year, 24-hour storm events. An S.C.S. Type IA, 24-hour rainfall distribution resolved to 10-minute intervals was used for the hydrologic modeling. The rainfall amounts in inches per 24-hours are 2.0, 2.9 and 3.9 for the 2, 10 and 100-year storm events respectively. The site currently drains to two localized drainage basins. In the existing condition, 0.66 acres drain to the southwest toward a wetland that is partially located onsite. The remainder of the site drains to the north. Please see Section III — Offsite Analysis of the Preliminary Storm Drainage Report prepared by Core Design. Inc. included in t�_ Appendix. � In the developed condition, the back yards and footing drains of lots 5-9 will drain towG the undisturbed wetland to provide wetland recharge. Captured runoff from the rest the site will be conveyed to the onsite detention pond. A small portion of the site unable to drain to the detention qond due to elevation and will be accounted for bypass in the pond modeling The detention facility was sized per Section 4.4.4 — Ponds of the 1990 KCSWDM. The interior features of the pond are designed according to Section 6.4.4 — Combined '',, Detention and Wetpoo! Facilifies of the 1998 KCSWDM. The site will incorporate a combination detention/wetpond to provide water quality. The wetpond is sized per Section 4.6.2 & 4.6.3 of the 1990 KCSWDM. The onsite conveyance system will be - tributary to the pond. � � #04-082 I B L U E 3-1 � LINE The Reserve at Stonehaven Storm Drainage Report The control structure for the detention pond is designed so that the peak flows from the pond added to the peak flows from the undetained bypass area are less than or equal to ' the peak flows from existing site for the 2, 10 and 100-year, 24-hour storm events. EXISTING SITE A detailed description of the existing site condition is included in the Level 1 Downstream Analysis found in the appendix. The following table shows the breakdown of the areas associated with the existing condition. The offsite upstream area is not included because it will be collected and routed around the detention facility. The existing condition does however include the area designated for frontage improvements. Please see the Existing Conditions Exhibit in the appendix. The complete StormShed modeling output is also included in the appendix. Sub-Basin A 0.541 acres Forested (CN = 81) 0.000 acres Impervious (CN = 98) 0.541 acres Total Sub-Basin B 4.642 acres Forested CN = 81) 0.341 acres Impervious (CN = 98) 4.983 acres Total The hydrographs for each sub-basin were computed individually, and then added together using the hydrograph addition option within StormShed to determine the maximum allowable flow from the site in its developed condition. The peak flows for the combined sub-basins for the predeveloped condition are shown in the Level Pool Routin section. The combination of these existing condition hydrographs will be compared against the combination of the pond outflow and undetained bypass area to ensure the developed condition flows do not exceed the existing condition flows. #04-082 I B L U E 3-2 LINE The Reserve at Stonehaven Storm Drainage Report DEVELOPED SITE Runoff from the developed site has been calculated based on the developed site plan. The lots were assumed to be 75 percent impervious, the maximum allowable amount by zoning code. A portion of the onsite area is not able to drain to the pond and will be accounted for as bypass. (Please see the Bypass Analysis later in this section) All areas have been delineated using AutoCAD. The following shows the breakdown of the land cover for Sub-Basin A (bypass) and Sub-Basin B. Please see the Developed Conditions Exhibit in the append x Sub-Basin A (Bypass� 0.137 acres I r,": . ;_._ - � . , � _ � = ' 0.092 acres Lawn — Lots @ 25% (CN = 8� 0.275 acres Impervious — Lots 75% (C' 0.504 acres Tot� *This area of impervious right-of-way is within Sub-Basin A. This area is not includec the bypass calculation because a comparable amount of offsite impervious area (S. 4 Street — 0.16 acres) is being collected and conveyed to the detention pond. This area is included in the Sub-Basin B area calculation. This is shown on the Developed Conditions Exhibit and is labeled as "Area Swap." Sub-Basin A will bypass the onsite detention facility and enter the Talbot Ridge detention facility. The Talbot Ridge detention vault was sized taking into account runoff from the undeveloped Stonehaven site. The developed runoff from Sub-Basin A (0.33 cfs, 100-year storm event) is less than the undeveloped runoff (0.42 cfs, 100-year storm event) that was accounted for in the detention vault sizing. Sub-Basin B 1.049 acres Lawn — Lots @ 25% (CN = 86) 3.147 acres Impervious— Lots @ 75% (CN = 98) 0.976 acres Impervious — ROW @ 100% (CN = 98) 0.164 acres Impervious—Area Swap (a) 100% (CN = 98) 5.336 acres Total #04-082 B LU E 3-3 LINE The Reserve at Stonehaven Storm Drainage Report A portion of the impervious frontage improvements (1,387 sf + 1,312 sf = 2,699 sfl will not be able to drain to the detention facility. Therefore, a comparable amount of additional impervious area along 102nd Avenue SE (2,381 sfl will be collected and directed to the detention facility to compensate for this. These areas are shown on the Developed Conditions Exhibit located in the appendix. i The following table summarizes all the areas included in the area swap. The "Give" - amount is the impervious area created by the project that is not being conveyed to the detention/water quality facility. The "Take" amount is the existing impervious area that the project will detain and treat for water quality in exchange for the "Give" amount. Give Take Location s s Sub-Basin A ROW 5,973 S. 47th Street 7,142 i S. 47th Street 1,387 102nd Ave SE 2,381 102nd Ave SE 1,312 Total 8,672 9,523 The hydrographs for each sub-basin are computed individually using StormShed. The hydrograph from Sub-Basin B will be used as the inflow to the detention pond. The hydrograph from Sub-Basin A will be combined with the controlled release rate hydrograph from the detention pond. The combination of these hydrographs represents the developed flow from the site which will be compared to the existing condition flow to ensure it is not exceeded. The developed condition combined hydrographs are shown in the Level Pool Routinq section. " LEVEL POOL ROUTING The control structure has been designed so that peak release rate from the pond added to the peak runoff rate from the developed Basin A (bypass) is less than or equal to the combination of Sub-Basin A and Sub-Basin B in the existing condition. The following shows the peak flow rates for Sub-Basin A and Sub-Basin B when the two hydrographs are combined together and also the peak flow rates for the pond control structure and undetained bypass area when the two hydrographs are added together. �``4 ",`,` '�i.uE � ��:F The Reserve at Stonehaven Storm Drainage Report 2-year Storm Event Predeveloped (Sub-Basin A + Sub-Basin B) ' Hydrograph ID: 2yr-combined-pre � A er a;5.5240 ac Hyd Int 10.00 min Base Flow � Peak flow j0.45� Peak Time j8.67 hrs Hyd Vol 0.3102 acft Developed (Pond Control Structure + Bypass) Hydrograph ID: 2yr-total-dev j Area 'S.7230 ac ' Hyd Int '�10.00 min Base Flow j ��, Peak flow;0.4550 c sf Peak Time 8.00 hrs � Hyd Vol 0.7117 acft 0.4550 (developed) < 0.4581 (existing) 10-year Storm Event Predeveloped (Sub-Basin A + Sub-Basin B) Hydrograph ID: 10yr-combined-pre i Area 5.524 ca0 ; Hyd ntl 10.00 min jBase Flow� 'Peak flow;1.0997 cfs '�Peak Time.8.50 hrs j Hyd Vol 0.615 acft� Developed (Pond Control Structure + Bypass) Hydrograph ID: 10yr-total-dev � Area j5.7230 ac ! Hyd Int i10.0�n !Base Flow j ; 'Peak flow 1.0606 cfs ;Peak Time '9.00 hrs � Hyd Vol ,1.13�j � 1.0606 (developed) < 1.0997 (existing) j 100-year Storm Event Predeveloped (Sub-Basin A + Sub-Basin B) Hydrograph ID: 100yr-combined-pre Area 5.5240 ac � Hyd Int 10.00 min ;Base Flow j i jPeak flow 1.9348 cfs Peak Time ,8.50 rsh � Hyd Vol 0.9959 acft� Developed (Pond Control Structure + Bypass) Hydrograph ID: 100yr-total-dev j Area j5.7230 ac � Hyd nl t �10.00 min ,Base Flow( �� Peak flow 1.8621 cfs Peak Time�8.50 rsh Hyd Vol 1.6078 acft'� 1.8621 (developed) < 1.9348 (existing) #04-082 e�u E 3-5 LINE The Reserve at Stonehaven Storm Drainage Report For each storm event the peak flow for the developed condition is less than that of the existing condition, thus satisfying Core Requirement #3: Runoff Control. The resulting detention facility as modeled is shown below. LPOOLCOMPUTE [pond] SUMMARY using Puls �Event , Match Q peak Q (cfs) Peak Stg (ft) Vol (cf) Vol (acftj Time to Empty , (cfs) �� I 2 year 0.3806 0.3826 2.0842 ; 94 15 29 ! 0.2170 , 41.00 i 10 year 0.9765 0.9943 2.7644 ; 13098.19 j 0.3007 '� 43.33 j 100 e ry 1.7143 1.7363 ; 3. 625 0 ;17529.55" 0.4024 ' 43.83 *The required volume to detain the 100-year storm event is 17,529 cubic feet. When the 30% factor of safety is applied, the minimum detention volume is 22,788 cubic feet (17,529 cf x 1.3). The provided detention volume is 23,593. The "Peak Q" shown above is the release rate from the detention facility. The actual release rate from the site is the combination of this release rate plus the runoff from the bypass area. The "Match Q" in the above table is not the actual target release rate since the target release rate was determined by adding the hydrographs of the two existing sub-basins. The following is the output from StormShed showing the modeled control structure. Record Id: MOrifice �Descnp Prototype Structure jlncrement ;0.10 ft Start EI. ,100.0000 ft Max EI. ;104.0000 ft Orif Coeff '0.62 Lowest Orif EL �0.00 Lowest Diam ;3.1250 in Dist to next 2.1600 ft ' ; D2 5.1250 in ;Dist to next 0.6800 ft ' iD3 4.2500 in �Dist to next 0.0000 ft Pond Control Structure Bottom Orifice Elevation 379.00 Diameter 3.125° Second Orifice Elevation 383.16 Diameter 5.125" Third Orifice Elevation 383.84 Diameter 4.25" #04-082 I B L U E 3-6 LINE The Reserve at Stonehaven Storm Drainage Report BYPASS ANALYSIS In the existing condition, runoff from a portion of the Stonehaven site sheet flows north to S. 47th Street, and is then conveyed to the Talbot Ridge detention vault. The area tributary to the Talbot Ridge detention vault in the existing condition is shown below: 0.00 acres Impervious (CN = 98) 2.16 acres Pervious (CN = 76) 2.16 acres Total In the developed condition, Sub-Basin A is not able to drain to the detention pond and will be accounted for as bypass. Storm runoff from this basin will be collected and tightlined to an existing catch basin located on the south side of S. 47th Street. The runoff is then conveyed to the Talbot Ridge detention vault. The area tributary to the Talbot Ridge detention vault in the developed conditions is shown below: 0.137 acres Impervious— ROW (CN = 98)'` 0.092 acres Lawn — Lots @ 25% (CN = 86) 0.275 acres Impervious — Lots (c� 75% (CN = 98) 0.504 acres Total 0.367 acres Total (excluding impervious ROW area) *This area is not included in the calculation of bypass flows because a comparable amount of offsite impervious area (S. 47�' Street — 0.16 acres) is being collected ar- conveyed to the detention pond. This area is included in the Sub-Basin B arE calculat . � � � . , _ - � �.... ��..�.�wiii� �u.,i�..� .��.:vvv .,:�. N-..ar�, i:vvvo aii�..i �cauiu:�y ,iyu.vy��a�..;�. vviu:i:c: '�.1; cal.ti storm event under the existing and developed conditions: #04-082 I B L U E 3-7 � ', L1NE The Reserve at Stonehaven Storm Drainage Report Peak Flow Rates 2-year 10-year 100-year Cfs Cfs Cfs �n±� r�` - � ,',.,; ,-.;��_ Existing Condition I _ 2.16 acres total 0.062 0.195 0.422 Developed Condition 0.367 acres total 0.161 0.251 0.354 Hydrograph Volume �. I ,D� - 6 �,-, 2-year 10-year 100-year c c c � Existing Condition 2.16 acres total 3,245 7,436 13,033 Developed Condition 0.367 acres total 2,113 3,284 4,617 Although the peak flow rates for the 2 and 10-year storm events are relatively higher for the developed condition, the total volume of water which reaches the vault is significantly lower in the developed condition. This means less stormwater runoff will reach the Talbot Ridge detention vault in the developed condition than in the existing condition. The Talbot Ridge detention vault has been modeled using the developed Talbot Ridge site plus the developed bypass area (Sub-Basin A) to make sure the previously modeled flow rates are not exceeded. The vault has been modeled assuming the dimensions used in the Talbot Ridge Storm Drainage Report (included in the Appendix) of 15' wide by 136' long by 10.6' deep. The following table shows the modeled rates from the detention vault with the upstream area (Stonehaven) in it's existing condition and also in the developed condition: Outflows from Talbot Ridge Detention Vault 2-year 10-year 100-year cfs cfs cfs Existin Condition 0.144 0.380 0.825 Develo ed Condition 0.138 0.313 0.625 Percent Decrease 14% 18% 24% The outflow from the Talbot Ridge detention vault will be less in the developed condition than in the existing condition. Therefore, the developed Stonehaven flows will not have an adverse impact on the Talbot Ridge detention vault. The StormShed output has been included in the Appendix. #04-082 I B L U E 3-$ LINE The Reserve at Stonehaven Storm Drainage Report EMERGENCY OVERFLOW In the event the inlet pipe becomes plugged, the primary overflow pathway is through the jailhouse section in the Type 2 control structure catch basin. The crest of the - jailhouse was set at the design water surface (384.60). The length of the jailhouse _ section was designed to pass the developed 100-year peak flow (4.58 cfs, see SformShed Output — Dev 8 Event Summary in the appendix). The following calculation was used to ensure adequate capacity of the 60-inch Type 2 catch basin with a jailhouse section. Q =�3.27+0.40 H�P}(L—0.2H�H'"` where: Q = flow, cfs H = head above crest, feet -� 0.50 feet P = distance from outlet IE to crest, feet � 3.6 feet L = length of opening, feet � 4 feet Q=�3.27+0.40�0.50�/3.6X4.0—0.2�O.S��X0.50��-= 4.59 cfs > 4.58 cfs The jailhouse section has adequate capacity with 0.50 feet of head. The pond overflow elevation is set at 385.10. The emergency overflow route is the rock lined overflow spillway. This was sized to convey the 100-year storm event if the primary overflo�v structure is plugged. The following equation was used to ensure adequate capacity. L — �� _�.-lH 3.21f� - Where: Q,00 = peak flow for the 100-year runoff event ,�f� -� 4 5R H = height of water ah^��p �.^.��r f�Pt � n �`� L = 4'S8 —2.4 x 0.40= 4.68 feet 3.21 x 0.403"` The required overflow spillway length is 4.7 feet. The minimum allowable length for the spillway is 6.0 feet. Therefore the desiqned spillway lenqth is 6 0 feet The emeraer overflow elevation is set at 385 ` ��4-�S� 3-9 IBLUE LINE The Reserve at Stonehaven Storm Drainage Report WATER QUALITY ANALYSIS AND DESIGN The water quality portion of the pond was designed to comply with the 1990 KCSWDM, Special Requirement #5: Special Water Quality Controls. There are two requirements for a wetpond that must be met and are detailed below. The first requirement is the wetpond surface area must be equal to or greater than 1% of the total impervious surface area in the drainage sub-basin contributing to the facility. The developed Sub-Basin B has 4.123 acres (179,598 s� of impervious surface coverage. Therefore the required wetpond surface area is 1,796 sf (179,598 x 0.01). The provided wetpond surface area is 5,344 sf. The second requirement is the design volume of the wetpond shall be at minimum the total volume of runoff from the tributary sub-basin of the developed site using the water quality design storm event. This is found by using a total precipitation of 1/3 of the 2- year, 24-hour total precipitation value (wq = 1/3 x 2.0 inches = 0.67 inches). This volume has been determined using StormShed and is shown below. IE nev t Peak Q (cfs) ,Peak T(hrs) Hyd Vol (acft) Area (ac) ;Method iRaintype ' ; wq 0.� 4131 j 8.01 ; 0.1337 5.3360 SCS �TYPE1A The total required volume is 0.1337 acre-feet or 5,824 cubic feet. The designed wetpond provides 10,749 cubic feet. #04-082 I B�u E 3-10 LINE The Reserve at Stonehaven Storm Drainage Report SECTION 4 Conveyance Svstem Analysis and Desiqn ONSITE PIPE SYSTEM The conveyance system was designed in accordance with the 1990 King County Surface water design manual (KCSWDM). The system has been designed to convey the 25-year, 24-hour storm event with a minimum of 0.5 feet of freeboard at each structure. Flows to each catch basin have been determined using the Rational Method for the 25- year storm event. These flows have then been entered into the King County Back Water (KCBW) computer modeling program. The table on the following page shows the flows tributary to each catch basin. -- _ - -- - - --- - - #04-082 �B�u E 4-1 L I N E The Reserve at Stonehaven Storm Drainage Report Tributary Flow Table Roads Lots 100% Im . 75°/o Im . Rational Flow Impervious Impervious Lawn C I A Q CB# acres acres acres acres cfs 1 0.00 0.00 0.00 0.00 2.73 0.00 0.00 -- -- __ __ _-------- --- - ---- ---_ __ ---- - - --- _ __ _ _---- - _ 2 0.00 0.47 0.15 0.74 2.73 0.62 ' 1.26 _ _ _ . _ 3 0.00 0.18 0.06 0.74 2.73 0.24 0.48 -- 4 0.00 0.38 0_12_ _0.74 2_73 _ 0.50 1.02 __------------------ --___ _----- ---- -- 5 0.00 ' 0.18 0.06 0.74 2.73 0.24 0.48 . _ __ 6 0.00 0.08 0.02 0.77 2.73 0.10 0.21 7 __0.00 ____ 0.00 0.00 0.00 2.73 0.00 0.00 _- - --- ---- - __ _--__ -- ---------__ ____------ 8 0.07 0.20 0.07 0.77 2.73 0.34 0.71 ___ __ 9 0.07 0.23 0.08 0.76 2.73 0.38 0.79 --. 10 0.00 0.00 0.00 0.00 2.73 0.00 0.00 __ ,._-- -- - ------- ----- -------- ----_---- - ---__. _- - ------ 11 0.09 , 0.00 0.00 0.90 2.73 0.09 0.22 _ 12 0.10 0.23 0.07 0.79 2.73 0.40 0.86 __ __-_ _ _ ___ 13 0.00 0.00 0.00 0.00 2.73 0.00 0.00 -- ------- --- -- --------__----- -- ----_ 14 0.05 0.00 0.00 0.90 2.73 0.05 0.12 _._ _ _ _. _ _ _ _ _____ 15 0.09 0.31 0.10 0.77 2.73 0.50 1.05 _ ____-- - _ _ --- --._ _ 16 0.00 0.23 0.07 0.75 2.73 0.30 0.61 _ -___----------- --- - --- - -- ------- ------__ _ ------------- 17 0.07 0.10 0.03 0.80 2.73 0.20 0.44 __ . _ _ _ _ _ _ 18 0.02 0.00 0.00 0.90 2.73 0.02 0.05 19 0.11 . 0.27 0.09 0.78 2.73 0.47 1.00 20 � 0.00 0.00 0.00 0.00� 2.73 0.00 0.00 _ _ __. _ _ . __- 21 0.03 0.00 0.00 0.90 2.73 0.03 0.07 __ ___---- __ _- _ _ 22 0.05 0.00 0.00 0.90 2.73 0.05 0.12 ----- _ .. ------------------__-------- 23 0.06 0.09 0.03 0.79 2.73 0.18 0.39 24 0.04 ' 0.10 - 0.03 0.79 2.73 0.17 0.36 _-_ _ _ _. _._ _ _ . __ 25 0.04 0.17 0.06 0.76 2.73 0.27 0.56 26 _0�00 0_00 _0.00 I_ 0.00 2.73 0.00__I__0.00 � _^ 0.10 ' 0.00 0.00 0.90 2.73 0.10 0.25 27 _ _ ---------- ___�_-_.,___--_--_--_---__�_--__ ___._____. -- ..�__I-------- 28 0.07 0.00 0.00 0.90 2.73 0.07 0.18 #04-082 I B L LJ E 4-2 LINE The Reserve at Stonehaven Storm Drainage Report Using the KCBW computer modeling program, the hydraulic grade line was calculated for each catch basin. The freeboard at each catch basin was also calculated and is shown on the foliowing table. Freeboard Table HGL CB Rim Elev. Elev. Freeboard # ft ft ft 1 386.75 ' 384.71 2.04 ----- --- -- 2 394.00 ` 384.96 I__ 9.04 __ 3 � 394.22 390.01 I 4.21 -_ 4 392.00 385.04 6.96 _._.._�_.__�_�______ u- _ 6 -�-- 392.25 ----�u 388.04 I 4.21 6 ' 390.00 i 385.31 4.69 - -I----�-_._ 7 � 390.00 385.45 I� 4.55_ _ � 8 386.63 385.76 0.87 9 ' 386.63 � 385.78 � 0.85 V � ; 10 390.95 ' 388.33 � 2.62 __-- _..�.___.--. --.--�------------__________._ 11 393.51 i 390.97 �_ 2.54 � 12 393.51� 390.97 � 2.54 � 13 �'-- 396.06 393.17 � 2.89� 14 398.36 : 395.51 2.85 --~- 15��'�---398.36 395.64 v 2.72 _.--- � ---------_ _ 16 � _ 396.00 i 386.37 � 9.63 17 i 397.45�' 393.41 � 4.04.� � 18 396.66 : 393.78 2.88 ��v 19 396.66 � 393.92 2.74 -- _ I_�_.______'__. --- --- 23 : 382.69 ; 379.34 I 3.35 ___ ___ �..-----------�-- --- -- __._-___._�___ 24 382.70 � 379.34 �� 3.36 25 ' 383.00 ` 379.06 �_ 3.94 _ � 26 '' 387.19 � 385.34 1.85 ____._.--- A_ _.._____.___�___-�-_-----._ _ 27 ` 386.96 � 385.34 1.62 #04-082 I B LU E 4-3 L�N E The Reserve at Stonehaven Storm Drainage Report OFFSITE DRAINAGE In the existing condition, offsite drainage enters the site near the eastern boundary and comes from two sources. The first source is a detention pond at the northeast corner of 102"d Avenue SE and SE 185�h Place. This detention pond drains west beneath 102nd Avenue SE through a 24-inch culvert. The second source is from a 36-inch underground detention pipe in 102"d Avenue SE. The control structure releases runoff to the site via a 12-inch culvert. Both culverts discharge at the same approximate location. From the discharge point, the runoff follows the natural topography north to an existing 48" x 36" arch culvert that runs beneath S 47th Street and outfalls to the north. ' In the developed condition, the runoff from the two discharge sources will be combined into a single catch basin and piped beneath the proposed Road A to a discharge point in Tract D. From there, the proposed grading will direct the runoff to a defined drainage ditch. The drainage ditch will convey the runoff around the proposed detention pond to the existing arch culvert. The existing arch culvert was sized to convey a flow of 32.62 cfs (please see the excerpt from the Talbot Ridge Storm Drainage Report prepared by Triad Associates, April 6 1998). Therefore, the proposed drainage ditch will also be sized to convey at minimum 32.62 cfs. Using Manning's equation and the following parame`ers. tne capa�i?y o` the propose� grass lined drainage ditch can be calculated. Bottom width 2 ft Side slopes 2:1 Depth of Water 1.5 ft Minimum slope 2.4°%�� n-value (grass lined) 0.030 ��.,. The Reserve at Stonehaven Storm Drainage Report SECTION 5 TESC Analvsis and Desiqn The temporary erosion and sedimentation control plan was designed to reduce the discharge of sediment-laden runoff from the site. The plan is comprised of temporary measures (rock entrance, filter fence, straw mulch, etc.) as well as permanent measures (hydroseeding and landscaping). The sediment ponds have been designed to help settle out sediments from the onsite runoff. The required sediment pond surface area is 2,�80 square feet per cfs of inflow for the undetained developed 2-year, 24-hour storm event. The site will be served by two sediment ponds. One pond will be located in the northwest corner of the site. The other pond will be located near the northeast corner of the site. The sediment pond surface areas were sized based on the total undetained site flow (Basin A + Basin B) for the 2-year, 24-hour storm event (2.25 cfs). The overflow riser was sized bas on the 100-year, 24-hour storm event (4.89 cfs). These flows have been proportioned to a flow per acre for the site. Peak Flows for Basin A- Developed � Event Peak Q (cfs) ;'Pea� k T(hrs) Hyd Vol (acft) ;Area (ac) � Method jRaintype, 2 year � 0.1488 � 8.�0 0.0397 0.3870 CS S!TY 1EP A i � 10 year 0.2341 8.00 j 0.0638 0.3870 i SCS �TYPE1A ', ,100 eary 0.3280 8 00 0.0950 ! 0.3870 ;S TYPE1A Peak Flows for Basin B- Developed ; E ev nt ,Pea Q fs) iPear k T(h�s) �Hyd Vol (acft) ;Area (ac) Method Raintype 2 year ; 2.1188 ; 8.00 0.6717 5.3360 SCS TYPE1A ;, j 10 year 3.2919 8.00 �� 1.0697 5.3360 I SCS TYPE1A � 100 year 4.5802 8.00 1.5115 � 5.3360 � SCS �TYPE A1 2-year (2.12 cfs + 0.15 cfs) /5.7 acres = 0.40 cfsJacre 10-year (4.58 cfs + 0.33 cfs) / 5.7 acres = 0.86 cfs/acre The sizing calculations for the two ponds are on the following pages. #04-082 I B L U E 5-1 LINE The Reserve at Stonehaven Storm Drainage Report Pond A Surface Area Tributary Area 2.7 acres Tributary Flow 1.08 cfs (2.7 acres x 0.40 cfs/acre) Required Surface Area 2,184 sf (1.08 cfs x 2,080 sf/cfs) The designed surface area of Pond A is 2.268 sf (28' x 81'). The top of pond dimensions will be 40' x 93'. Dewatering Orifice A = As��h�� ° 0.6 x 3600Tg � where: Ao = orifice area (sfl A5= pond surface area (s� � 2,268 sf provided h= head of water above orifice (height of riser in feet) -� 3.5 T= dewatering time (24 hours) g= acceleration due to gravity (32.2 ft/sec) A _ 2,268�2 x 3.5�°5 - 0.0204 sf ° 0.6x3600x24x;?.?�' D = 24��A � where: D = orifice diameter (inches) Ao = orifice area (sfl 0. 200 4 D = 24�� = 1.93 in � Use 2-inch diameter dewatering orifice ,z #04-082 I B L LJ E 5-2 LINE The Reserve at Stonehaven Storm Drainage Report Overflow Riser Qo = 3.782D'-H?, where: Qo = discharge flow (cfs) D = riser diameter (ft) H = head above riser (ft) Qo = 3.782 x 1.0' x 1.0''''= 3.78 cfs Because the riser is required to pass 2.40 cfs (2.7 acres x 0.86 cfs/acre), a 12-inch riser which can pass 3.78 cfs will be adequate. Pond B Surface Area Tribut� Tributary Flow 1.20 cfs _ _ ._ __ _ _ Required Surface Area 2,496 sf(1.20 cfs x 2,080 sf/cfs, The designed surface area of the west pond is 2,523 sf (29' x 87 �. The top of pond dimensions will be 41' x 99'. Since the permanent detention pond has a surface area �= 5,344 sf at the liveldead interface, the permanent detention pond without the berr,� installed may be used as a sediment pond during construction in lieu of temporary sediment Pond B. If it is used, all sediment accumulated during the construction process should be removed when construction is complete. Dewatering Orifice A _ AS(�Ir) _ ° 0.6 x 3600Tg � where: Ao = orifice area (sf) AS= pond surface area (sf) � 2,523 sf provided h= head of water above orifice (height of riser in feet) -� 3 5 T= dewatering time (24 hours> g= acceleration due to gravity (32 2 ft/sec) -- _ — - __ ---—---- - -- -- -___ - ---- _ _-- #04-082 I e�u E 5-3 LINE The Reserve at Stonehaven Storm Drainage Report A _ 2,523�2 x 3.5�°5 - 0.0227 sf ° 0.6 x 3600 x 24 x;2.2os D = 24,IA° V � where: D = orifice diameter (inches) Ao = orifice area (s� 0.0227 D = 24 = 2.04 in -� Use 2-inch diameter dewatering orifice � Overflow Riser Qo =3.782D�H�'� where: Qo = discharge flow (cfs) D = riser diameter (ft) H = head above riser (ft) Qo = 3.782 x 1.0' x 1.0''z= 3.78 cfs Because the riser is required to pass 2.58 cfs (3.0 acres x 0.86 cfs/acre), a 12-inch riser which can pass 3.78 cfs will be adequate. #04-082 I B L U E 5� LINE The Reserve at Stonehaven Storm Drainage Report �►ppendix (BLUE A L1NE SEC TWP RGE TME � BLUE ` LI N E WETLAND ' EXISTING CONDITIONS — BASIN A EXISTING CONDITIONS — BASIN B — OROUP WETLAND + BUFFER 0.240 AC IMPERUIOUS 0. 000 AC IMPERI/IOUS 0. 341 AC ��W�•.��°° �.�� v:uu�e,ne� F:saa2ienom TRIBUTARY AREA 0. 424 AC FORESTED 0.541 AC FORESTED 4. 642 AC ' '""""�`°�'�°"°"P�" TOTAL AREA 0. 664 AC TOTAL AREA 0. 541 AC TOTAL AREA 4. 983 AC � ' � -: �. �' � 2 m �. � _ _ _ _ : � - - — ,. z, � :�, ,.. . ,� � � �-:�.�- s—�.w.�_-- — -— — 3 `- A =�—==—— = ——-----— --- - � k a __ : __ _ _ —T —— — — — —— -- --- ---- . _� _ - -�- ----------- - - -------- --- -- -Y= -- - - . __ _ .> : _ _ � � � ---�- - T ---- ...� --_ - - _ _. _ _ , . . . - : ` _ , . .: _ , _ . ;:_ _: _ -- _ _ _ __ � _ _� - -�- -_ , _ f ` W Z W _ _ _ _ _ _, -�r Tv: _ . � � " � :,� :� _ ,'. . �. � S. 4 7TH .STREET _ _ _ � _ . , , ,� O , � : . , .� , — _ . r__ � � ,-{ _ _ _ —, _ . . , n\ � � �,_ _._____. _;�_. - _ �_ ,. . 9 _ � i' � t_ - - -- � -- , $ �,I � = Q , /,,+�) ,, - ` � I �� . . .. .. . ._ ` � .. �1.� . . 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AREA SWAP _ �— � N E :� `,. , � ; �, ��t�' "� AREA SWAP _ G/�E 8, 672 SF �R�"P 75 CEMRAL WAV.$UfTE�Op � AREA SwAP 7, 142 SF (TAKE) _ _-�� _ _ __ :_ TAK� 9, 523 SF ,�„��,F,��, 5,973 SF _(G/VE�_-- --- _ - _ _ -- --- - — -- _ ,: _ — - - ��T � —— —--4 T-==, _ __ _ -- ---- --------------- - , -- -�-- - ., -. . _ - ----- ----------------- � _� . - - --- - . _ - z �._� �___�-�__--�------- --- - - - `- , o — � ---, _ . __ � ..��_ -- --- -:_ . ----- _ _ _ __ _ _ _ _ _ _ _ __�� . , __ � __ _ , � t� --- � - �.. 2 — — — — _ � m , _ — , _ � =`� , h , n _ � _ , �-- —� =—T-- — —— � . , E .. ,_�.. — — — — — — >�,� — � — ------_— _��--! _-�— _------ i __ . . � ' REA SWAP = � ��.�_ - - - - _ _ -- -- - ,� , -- --- - , , „ ,387 SF (Gl l/E) W a 3 _ . ,, � � -�az •-'--=' � ; , � . � � 384-.---� � t I � . ... .. �I - I ' . . I /�� _ � ; � , � �, - -L;� i W � , , '; ( ; , � � I , � ; '� BASIN A` � ; : _ �' _ �� . 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II ,t `\ ��III1��o� � I !I f U i`� . ," .' , . ' .' ;.I --- - 111L-_�1rf ---__- -.. �1 - 11 ..� I ...,. �.. � �`I 11 :I� ni�, i � ' I-ORIZ:1"�6d VER�,-.N/A ��-: AREA SWAP , ,, � , �� ; � S/N J� '---------------= - .I �'� `,�',�;,i , � ; �:.2,381 SF (TAKE) �,.N,��_�-_ i I . �\ � I i '....._ _._' � 1 . � . . . � ii �..I � . � �� 1 . P40JECT MANAGER�.>.. I - -392 I � 1 I h. I I'� I o,�o� � I; i m�r ivnrawa _ �� i � �.L _.J' J . 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W � � � � � J r � _ Z -- -- - -- --- ------- \{`'�, W s. i �. � � �, .. , �, '°,�, � f f r � �� i ------ aoo - -- --- ------- � � � � i � �------ ------ -'------ ----aoz--- - - ' � .� y _ _ �. � _ - �J� - -- ' , i ;� _�� INFTLAND DEI/ELOPED COND/T/ONS — BAS/N A DEVELOPED COND/TIONS — BAS/N B � �` � � ��—� WETLAND + BUFFER 0.240 AC IMPERVIOUS — ROW 0. 137 AC IMPERI/IOUS — ROW 0. 976 AC � RECHARGE 0.236 AC IMPERI/IOUS (75q"—LOTS) 0.275 AC . IMPERI/IOUS (75�—LOTS) 3. 147 AC I `�� N �, , TOTAL AREA 0. 476 AC LAWN (25�—LOTS) 0. 092 AC IMPERI//OUS (SWAP) 0. 164 AC ; /.�� 1 ; SCALE: 1�� = 60, JOHNLJMBER: ` TO TAL AREA 0.504 A C LA WN (25q"— ) ; I i o ,5 3a bo a4-oaz LOTS 1. 049 AC � _ ,t�},� F3_._k T O T A L A R E A 5. 3 3 6 A C ; I ;� , �,. ,.� - . ._� ��t,<< � �__.� r. -_ � �� , .. . . , . .. ... �� I ,,, arrr �, aF �, ! - .-. � Q40D�7NE BWELNE tltWP Ii , SEC TWP RGE �THE �__ BLUE L1NE C3ROUP 73 CBlTRAL WAY,9UfE�00 IQaQNO.WA 9lD93 . . �.,.. __ ... . _ . . .. .. .. _...._ ... P.�75276.106� F:1?b216.10R . .... ..._, __ _ ._ _." ..�- WYVW.TlEBUJELIlEO�UP.CON ,.., .. _ - .. _ � - • ' •'� -' _ - . x � " . � :.i�, .. . � ,. .:"'` _.__..._. ._.. ...s- __._ .. � _,. _ .. .� _____ -. � .... _ . �.�,___._. . �--- . :�-...- - -- -- _. . . : • .. � 28 ' ` j' �. w�� — — — 1� i � _. . . z .. . _ — — v � . i C� �. ':' .. —_—��— . � . ; v .�a .��. .H :;: .:' �� /�p „ __.... .. .. ._ .� . ... -' �u � _ . i . ,„ � -, l..D 27 .. . -, . . ....__ ��' � n_ �. . .:, .. ..._ _: � � ` � . .... - � .. TT1 . .' ' - \ ..,, ..� . .. �, YJ . . . :i ; . .� . ...— —.� \-� _ �.:.-. — _ � — � — ..._ — '_ — _ I : . .. . � . ' 382--'� —� \�. . 1:... - ... .. ,,., .. .I. ,�� . �� " :�I k � Q 384— — � .. . . � , � �� ,; 0 3 � _ ._� I - ' ,� � F W � 4 ' 25 '1� f f ; cs z4 i �� ' � ; ��'� - -�`� c 2� W � � �- ` , , •, � , ' `\ , i � 1., ' , � 1 __ ,. > _ ' � �81 ` \ — — — — — �. I ! � , __ � �ry� Q �1 — — — — — � � I W ? I CB 4 Q � � � i I� = '� i � _. < i _ ,_ y � 6 — — — � I I � ,} I . ..... .— — —.-�J� -- — — " — —---�� 92394— — � � ._. . - IL 3 �� , � I 3 8 y \ � — � — — — — �` _ Page 1 of 4 �t�r�11-j 1N�ia�4:�t..1 n�C� Appended on: 13:46:13 Monday, Apri125,2005 LPOOLCOMPUTE [Level Pool] SUMMARY using Puls Event '.Vlatch Q (cfs) Peak Q (cfs) Peak Stg(ft) Vol (c� Vol (acft) Time to Empty 2 year 0.3806 0.3826 2.0842 9451.29 0.2170 41.00 10 year 0.9765 0.9943 2.7644 13098.19 0.3007 43.33 100 year 1.7143 1.7363 3.5260 17529.55 0.4024 43.83 100 year Hydro�raph Plot ----�---�---�--�--�- i--�--�--�------ -�- -�--i--i--�--�- 4 -- --- - ;�-�-pevB---- - , -=--:--;---�--'---=- =--=--=--=--- - ------------------------ - -ye�rtx5t- - ;� �"f 88; u 3 � � ' � � � � � � , , � � � � � � � � , , � � � � � � '�"'�_'_�_"r"�"r_ 'i__i"_�"_�_"�'_'�"�'_r"r"r'_i"�"',"'�"_�"'r",-"r_'r � 2 --"- ----" -- - -- - -'--"- - --'-- ' - '- -- � -- -- -- ------ - - - - - - -- - - 1 ; 0 � '. ,., , ('7 O �`': h. p (+'7 1� O ('7 1�- O C�l h� O f''1 1� O (�'7 I� O ('7 I'+ O M t+� O (�'� 1� N lfi (`7 O O7 CD U] C'i O 00 (D � f�i � O 00 CO N� C'1 O N (D Ul ('') ' � N (�'7 V � U7 CO 1� �7 � O O N t�i d ll7 lfl fD 1� W m O O N M � � � � � � r � � N N N N CY N � Time in Hours Running E:11Projects\\0408211EngineeringllStormShedl\Level Pool Report.pgm on Monday, April 25, 2005 Summary Report of all Detention Pond Data Event Precip (in) I wq 0.6700 2 year 2.0000 10 year 2.9000 I 100 year 3.9000 � BASLIST2 [Predev B] Using [TYPElA] As [2 year] , [Dev B] Using [TYPEIA] As [2 year] ' [Predev B] Using [TYPE 1 A] As [10 year) [Dev B] Using [TYPElA] As [10 year] [Predev B] Using [TYPElA] As [100 year] [Dev B] Using [TYPElA] As [100 year] LSTEND BasinID Peak Q (cfs) Peak T (hrs) Peak Vol (ac-c fl Area (ac) Method/Loss Raintype Predev B 0.4229 8.62 02828 4.98 SCS/SCS TYPEIA Dev B 2.1188 8.00 0.6717 5.34 SCS/SCS TYPEIA Predev B 1.0172 8.56 0.5592 4.98 SCS/SCS TYPElA file:i-'E:1Projects',04082'�,E�ngineering`,StormShed'�,04082 - CL?RREI�'T (3-1-OS).html 4,`2�i200� Page 2 of 4 Dev B 3.2919 8.00 1.0697 5.34 SCS/SCS TYPEIA ', Predev B 1.7858 8.49 0.9034 4.98 SCS/SCS TYPElA , Dev B 4.5802 8.00 1.5115 5.34 SCS/SCS TYPEIA , BASLIST [TYPElA] AS [2 year] DETAILED [Predev B] [Dev B] LSTEND Recard Id: Predev B ' Design Method SCS Rainfall h-pe TYPElA I Hyd Inri� 10.00 min Peaking Factor 484.00 Abstraction Coeff 0.20 Pervious Area 4.98 ac DCIA 0.00 ac Pervious CN 82.16 DC CN 0.00 Pervious TC � 57.64 min DC TC 0.00 min � Per��ious CN Calc Description SubArea Sub cn ' 2nd Grow�th Forest 4.64 ac 81.00 � Impervious surfaces (pavements, roofs, etc) 0.34 ac 98.00 Pervious Composited CN (AMC 2) 82.16 Pervious TC Calc II Type Description Length Slope Coeff Misc TT 300.00 2 00 5�.62 Sheet Woods or forest with light underbrush.: 0.40 �3.00% 0.4000 in min I ❑ Shallow �ri re�slo)heavy ground litter& meadows ft35.00 12.00% 0.1000 2.02 min �� Pervious TC 57.64 min Record Id: Dev B Desi n Method SCS Rainfall type TYPElA Hyd Inh� 10.00 min Peaking Factor 484.00 Abstraction Caeff 0.20 Pervious Area 0.00 ac DCIA 5.34 ac Pervious CN 0.00 DC CN 95.64 Pen�ious TC 0.00 min DC TC 3.30 min � Directly Connected CN Calc �� file://E:1Projects104082�EngineeringlStormShed104082 - CURRENT (3-1-OS).html 4:`25!2005 Pa�e � of 4 IDescription I SubArea Sub cn Impervious surfaces (pavements, roofs, etc) 4.29 ac 98.00 Open spaces, lawns,parks (>75% grass) 1.05 ac 86.00 DC Composited CN (AMC 2) 95.64 i: Directiv Connected TC Calc Type Description Length Slope Coeff Misc TT Channel (interm) Concrete pipe (n=0.012) 940.00 ft 1.25% 0.4120 3.30 min I, I�irectiv Connected TC, �.��min � --__-----__ ___ _-- - --------- --_ _ -_-- ---- ____ -__ _ _ ______ _ __-__ � ______ ____�� HI'DLIST SUi�Z�7AR� [2 year out] [10 year out] [100 year outj LSTEND HvdID Peak Q (cfs) Peak T (hrs)��Peak Vol (ac-ft)j�Cont Area (ac)�! 2 year out 0.38 12.17 0.6719 5.3360 10 year out 0.99 9.17 1.0712 5.3360 100 year out 1.74 8.67 1.5127 5.3360 STORL T` [Trap] LSTEnI Record ld: Tra Descrip: Protot}pe Record��Increment � U.1 U ft Start El. 100.0000 ft Max El. 104.0000 ft Length 95.0000 ft Width 41.5000 ft Length ssl 2.00v:lh Length ss2 2.00OOv:Ih W'idth ss 1 2.00v:1 h Width ss2 2.00OOv:1 h DISCHLIST [MOrifice] LSTEND Record Id: MOrifice Descrip: Prototype Structure Increment 0.10 ft Start El. 100.0000 ft Max El. 104.0000 ft Orif Coeff 0.62 Low�est Orif El. 0.00 ' Lowest Diam 3.1250 in Dist to next 2.1600 ft � file://E:1Projects1040821EngineeringlStormShed104082 - CURRENT (3-1-OS).html 4,�25/2005 Page 4 of 4 D2 (5.1250 in I Dist to next 0.6800 ft D3 �4.2500 in Dist to next 0.0000 ft Licensed to: The Blueline Group tile:��I_:��Project��0�}�)��Engineerin��StormShed�(J-�08�� - C[_-RRf�:A1 (�-I-U�I.hm11 -1�� i��1� Page 1 of 1 Appended on: 14:22:06 Monday, Apri125, 2005 Dev A Event Summary Event Peak Q (cfs) Peak T (hrs) H��d Vol (acft) Area (ac) Method Rainty e . wq 0.0000 0.00 0.0000 0.0000 SCS TYPElA 2 year 0.1488 8.00 0.0397 0.3870 SCS TYPEIA 10 year 0.2341 8.00 0.0638 0.3870 SCS TYPEIA 100 year 0.3280 8.00 0.0950 0.3870 SCS TYPEIA Record Id: Dev A Design Method SCS Rainfall type TYPE 1 A Hyd Intv 10.00 min Peaking Factor 484.00 Abstraction Coeff 0.20 Pervious Area � 0.00 ac DCIA 0.39 ac I Pervious CN 0.00 DC CN 94.99 ' Pernious TC 0.00 min DC TC 0.56 min ; Directly Connected CN Calc Description SubArea Sub cn Impervious surfaces (pavements, roofs, etc) 0.29 ac 98.00 Open spaces, lawns,parks (>7�% grass) 0.10 ac 86.00 DC Composited CN (AMC 2) 94.99 Directly Connected TC Calc Type Description Length Slope Coeff Misc TT Channel (interm) Concrete pipe (n=0.012) 200.00 ft 2.00% OA120 0.56 min I', Directiv Connected TC 0.56min � Licensed to: The Blueline Grc Page 1 of 1 Appended on: 14:22:12 Monday,Apri125, 2005 Dev B Event Summary Event Peak Q (cfs) Peak T (hrs) Hyd Vol (acft) Area (ac) Method Rainty e wq 0.4131 8.01 0.1337 5.3360 SCS TYPEIA 2 year 2.1188 8.00 0.6717 5.3360 SCS TYPElA 10 year 3.2919 8.00 1.0697 5.3360 SCS TYPEIA 100 year 4.5802 8.00 1.5115 5.3360 SCS TYPE1_A �z«<�►-�i i�i: u�� ir - -- -- _ -___ _ , -_ _---- - - - ��ll�sib►i .�lctt�od j� �L5 j�llainfall t��pc � II 1 � 1'L i:1 � Hvd Intv 10.00 min Peaking Factor 484.00 Abstraction Coeff 0.20 Pervious Area 0.00 ac DCIA 5.34 ac Pervious CN 0.00 DC CN 95.64 Pervious TC 0.00 min DC TC 3.30 min Directly Connected CN Calc Description SubArea Sub cn Impervious surfaces (pavements, roofs, etc) 4.29 ac 98.00 Open spaces, la��ns,parks (>75% grass) 1.05 ac 86.00 DC Composited CI� (AMC 2) 95.64 Directly Connected TC Calc Tvpe Description Length Slope Coeff Misc TT Channel (interm) Concrete pipe (n=0.012) 940.00 ft 1.25% 0.0120 3.30 min Directiv Connected TC 3.30min Licensed to: The Blueline Group ji � II file://E:1Projects1040821EngineeringlStormShed104082 - CURRENT (3-1-OS).html 4/25/2005 Page 1 of 1 Appended on: 14:22:19 Monday, Apri125, 2005 Predev A Event Summarv Event Peak Q (cfs) Peak T (hrs) H��d Vol (acft) Area (ac) Method Raintype � wq 0.0000 0.00 0.0000 0.0000 SCS TYPEIA 2 year 0.0510 8.13 0.0274 0.5440 SCS TYPElA 10 year O.li28 8.11 0.0�61 0.5440 SCS TYPElA 100 year 0.2404 8.11 0.0925 0.5440 _SCS_ TYPEIA Record Id: Predev A Design Method � SCS Rainfall tvpe TYPEIA Hvd Intv 10.00 min Peaking Factor 484.00 Abstraction Coeff 0.20 Pervious Area 0.54 ac DCIA 0.00 ac Pervious CN 81.00 DC CN 0.00 Pervious TC 21.34 min DC TC 0.00 min Pervious CN Calc Description SubArea Sub cn 2nd Growrth Forest 0.54 ac 81.00 � Pervious Composited CN (AMC 2) 81.00 Pervious TC Calc Type Description Length Slope Coeff Misc TT Sheet Woods or forest with light underbrush.: 0.40 22�.00 ft 14.00% 0.4000 2.50 in 21.34 min Pervious TC 21.34 min Licensed to: The Blueline Group ,�-!. .�: .�J file://E:1Projects1040821EngineeringlStormShed104082 - CURRENT (3-1-OS).html 4/25/2005 Page 1 of 1 Appended on: 14:22:25 Monday, Apri12�, 2005 Predev B Event Summary Event Peak Q (cfs) Peak T (hrs) Hyd Vol (acft) Area (ac) Method Raintype wq 0.0145 24.09 0.0100 4.9800 SCS TYPEIA 2 year 0.4229 8.62 0.2828 4.9800 SCS TYPEIA 10 year 1.0172 8.56 0.5592 4.9800 SCS TYPEIA 100 year 1.7858 8.49 0.9034 4.9800 SCS TYPEIA Record Id: Predev B Design 1Zethod SCS Rainfall h�pe TYPE 1 A Hyd Intv 10.00 min Peaking Factor 484.00 Abstraction Coeff 0.20 Pervious Area 4.98 ac DCIA 0.00 ac Pervious CN 82.16 DC CN 0.00 Pervious TC 57.64 min DC TC 0.00 min Pervious CN Calc Description SubArea Sub cn 2nd Grow�th Forest 4.64 ac 81.00 Impervious surfaces (pavements, roofs, etc) 0.34 ac 98.00 Pervious Composited CN (.A:VIC 2) 82.16 Pervious TC Calc Type Description Length Slope Coeff Misc TT 300.00 2 00 55.62 Sheet Woods or forest vvith light underbrush.: 0.40 �3.00% 0.4000 in min Shallow �n re�sl�wj heavy ground litter&meadows ft 5.00 12.00% 0.1000 2.02 min ��❑ � Pervious TC 57.64 min Licensed to: The Blueline Group file:i/E:',Proje�cts''�,040821EngineeringlStormShed'�,04082 - CURRENT (3-1-05).html 4;`2�/200� Page 1 of 1 Appended on: 13:59:42 Monday, Apri12�, 200� Stonehaven-ExistingUpstream Event Summary Eveot Peak Q (cfs) Peak T (hrs) Hvd Vol (acft) Area (ac) Method Rainty�pe 2 year 0.0617 12.67 0.0745 2.1600 SBUH Userl 10 year 0.1951 8.33 0.1707 2.1600 SBUH Userl 100 year 0.4220 8.17 02992 2.1600 SBUH Userl Record Id: Stonehaven-ExistingUpstream Design Method SBUH Rainfall type Userl � Hyd Inri� 10.00 min Peaking Factor 484.00 Abstraction Coeff 0.20 � Pervious Area 2.16 ac DCIA 0.00 ac Pervious CN 76.00 DC Cn 0.00 Pervious TC 50.98 min DC TC 0.00 min Pen�ious CN Calc Description SubArea Sub cn Meadow•or Pasture 2.16 ac 76.00 Pervious Composited CN (AMC 2) 76.00 Pervious TC Calc Type Description Length Slope Coeff Misc TT Fixed 50.98 min Pervious TC 50.98 min Licensed to: The Blueline Group i I Page 1 of 1 Appended on: 14:00:02 Monday,Apri125, 2005 Stonehaven-BypassArea Event Summary Event Peak Q (cfs) Peak T (hrs) H}�d Vol (acft) Area (ac) Method Raintype 2 year 0.1612 7.83 0.0485 0.3800 SBUH Userl ; 10 yeaz 02515 7.83 0.0754 0.3800 SBUH Userl 100 year 0.3537 7.83 0.1060 0.3800 SBUH Userl Record Id: Stonehaven-BypassArea Design Method SBUH Rainfall tvpe Userl Hvd Int�� 10.00 min Peaking Factor 484.00 Abstraction Coeff 0.20 Pervious Area 0.10 ac DCIA 0.28 ac Pervious CN 86.00 DC CN 98.00 Pervious TC 5.00 min DC TC 5.00 min Pervious CN Calc Description SubArea Sub cn Open spaces, law-ns,parks(<50% grass) 0.10 ac 86.00 Pen�ious Composited CN (AMC 2) 86.00 Pervious TC Calc Type Description Length Slope Coeff Misc TT Fixed 5.00 min I Pervious TC 5.00 min Directly Connected CN Calc Description SubArea Sub cn ' Impervious surfaces (pavements, roofs, etc) 0.28 ac 98.00 DC Composited CI�' (AMC 2) 98.00 Directly Connected TC Calc Type Description Length Slope Coeff Misc TT Fixed 5.00 min Directly Connected TC S.00min Licensed to: The Blueline Group file::';'E:`�Proje�cts\040821E�ngine�ering`1StormShe.d�',TalbotRidge�%ault-BJD`�,Stoneha��en.html 4;`2�;`?00� Outflow from Vault in Existing Conditions Appended on: 13:52:53 Monday,April 25, 2005 Hydrograph ID: Talbot-VaultOutflo�v-2yr �- ; A er a�5.8800 ac Hyd Int 10.00 min Base Flow �- Peak flow ,0.1436 cfs;Peak Time 24.1�7 hrs Hyd Vol !0.50 30 ca ft� �� Appended on: 13:53:20 Monday,April 25, 2005 �i Hydrograph ID: Talbot-VaultOutflow-l0yr I � Area ,5.880 ac0 ; Hyd Int 10.00 min Base Flow �� jPeak fl wo 0.3795 cfs Peak Time�16.83 hrs Hyd Vol '�0.85 51 ca�ft'; �', Appended on: 13:53:36 Monday,Apri125, 2005 Hydrograph ID: Talbot-VaultOutflow-100yr !, i Area ;'S.8800 ac � Hyd Int �10.0�Base Flow � ,Peak fl��o j0.8249 cfs Peak Time;11.17 hrs ; Hyd Vol �1.2732 acft i Outflow from Vault with Developed Bypass Area Appended on: 13:54:49 Monday,April 25, 2005 Hydrograph ID: Stonehaven-VaultOutflow-2yr j Area !4.1000 ac , Hyd Int 10.00 min Base Flow �-� Peak flow;0.1381 cfs Peak Time;24.00 shr Hyd Vol .0.474 acft' Appended on: 13:55:14 Monday,Apri125, 2005 Hydrograph ID: Stonehaven-VaultOutflow-l0yr , Area ';4.1000 ac Hyd Int ,10A��Base F wol ' '� Peak flow�0.313 cfs Peak Time�16.67 hrs � Hyd Vol ;0.7�6 ca2 ft Appended on: 13:55:2� Monday,Apri125, 2005 Hydrograph ID: Stonehaven-VaultOutflow-100yr � A er a�4.1000 ac Hyd Int ,l 0.0�,�Base Flow : I Peak flo�i� 0.62��Peak Time.12.67 hrs I Hyd Vol i1.07 99 ca�ft BA�KR'ATER CCI✓PUTcR FRCGR�9 rC�: �__'=� Pipe data from file:al.bwF Surcharge condition at in~_�r-._uia-� � -.____�.s Tailwater Elevation:389 . E �eet Discharge Range:7. 63 to 7. 63 Step of 1 . ;�fs: Overflow Elevation:398.36 f�e= Weir:NONE Upstream Velcc_ty: �. feet/s�� OUTFALL -� CB 1 PIPE N0. 1 : 2i �F - 24"�F � 9. 86a O;i7L�T: �-9.u� IN�ET: 3di . �? �NTYP: 5 J'JNC N0. 1: OVERFLOW-E�: 386.75 BEND: �5 D�'G DIA/WIDTH: 2.5 Q-RATIO: 0. 0� Q(CFS) HW(FT) Y_W ELEV. * N-�'AC DC DN TW DO DE HWO HWI *�****�***********x+>***x***x*��**�x�***�*�*****�*+**********x***************+* 7.63 3.64 384 .71 * 0.012 0.99 0. 43 5.60 5. 60 3.56 3. 64 1.27 Cs 1 � CB 2 PIPE N0. 2: 144 LF - 24"CP @ 0. 5C� OL'TLE'�': 381. �? INLET: 381.79 INTYP: 5 JUNC N0. 2: OVERFLOW-EL: 394 .00 BEND: 0 DEG DIA/WIC_H: 4 .0 Q-RATIO: 0.30 Q(CFS) HW{FT) HTn ELEV. * N-FAC DC DN TW DO DE HrtiO HWI *******�*�x**��**********+++***************x********�*�*x�*+��**+*****��*****+* 7. 63 3. 17 384 . 96 x 0.012 0. 99 0. 93 3. 64 3. 64 3. 07 3.17 1 .38 CB 2 -� CB 4 PIPE NO. 3: �18 LF - 24"CP @ 0.50$ OUTLE�: 381.79 INLET: 382. 38 INTYP: 5 JUNC N0. 3: OVER�LOW-EL: 392.00 BEND: 0 DEG DIA/WIDTH: 4 . 0 Q-RATIO: 0.34 Q(CFS) HW{FT) HW ELEV. * N-FAC DC D� TW DO D� HWO HWI ***x*****�*********x****�***�*x***�****��********�**��***��+**********x****** 5.89 2. 66 385.�4 * 0.012 0.86 0.81 3.i7 3.17 2. 65 2.66 1. 14 CB 4 � CB 6 PIPE NO. 4 : 59 LF - 18"CP @ 0. 49$ OUTLET: 382.38 INLET: 382. 67 INTYP: S JliNC NO. 4 : OV'c�RFLOW-EL: 392. 00 BEND: 9C DEG DIA/WIDTfi: 9 .0 Q-RATIO: 0. 17 Q(CFS) HW(FT) H5d ELEV. * N-FAC CC �N TW DO DE Hr�nTO HWI *********�**************�***�***x=*****+*x,:�*****�**�*****x**�<**�********�*+** 4 .39 2. 64 385.32 * 0.012 0.81 0. 80 2. 66 2. 66 2.46 2. 6� 1.21 CB 6 � CB 7 PIPE NO. 5: 13 LF - 18"CP @ 0. 54°� OUTLET: 382 . 6� I?�LET: 382. 75 INTYP: 5 �L'NC N0. 5: OVERFLOW-EL: 392. 00 BEND: 90 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*********x*********************** 3.75 2.71 385.45 * 0.012 0.75 0.71 2. 64 2. 64 2.58 2.71 1.09 CB 7 � CB 8 PIPE PdO. 6: 98 LF - 18"CF �? 0. 5G$ O�TL�T: 382. 74 IN��T: 383.23 =�TYP: � JUNC N0. 6: OVERFLOW-EL: 386. 63 BEND: 90 DEG DIA/WIDTH: 2.5 Q-RATIO: C. 6, Q(CFS) HW(FT) HW ELEV. * �-FAC DC DN TW DO DE HWO H�r�i **�*********�*��********�*x**+****�***x**************x**�*******�**�*+*�**>i*x 3.i5 2. 53 385 .?5 * 0.012 0.?� 0.?2 2 . ?1 2. ?1 2. 33 2. 53 � . 16 CB 8 -� CB 10 PIPE N0. 7. �� F - "_� �F� s 4 . 3�� T=E!. �8�. , _ TPv��T. �� , .45 I.�_YF. � JUNC N0. 7 : OVERFLOW-EL: 390. 95 BEND: 30 C?G DIA/W-DTH: 2. 5 Q-RATIO: O. f.= Q(CFS) HW(FT) 3W E�EV. * N-rAC DC DN TW DO DE HWO H��:= *fx*******�*�***+x*�***x**�x***+****x**x**}�*�*x+*+x*******�***�*�**�*+�****�xx � . G�i O. _.. ___ . �� ' . . �_2 � . . ._ � . 3, L . .,'� _ . u3 U. . _ ,.+k�.+ C �H CB 10 � CB 11 PIPE NO. 8. �_ �� - i� �F , _ . � ,� ,,.._�__ . ��- . .� 1��:�=_ . �� . 0, __,___ . � �UNC NO. 8: GVERFL0�9-EL: 393.5i ^BEtiD: iU Cr�: DIA/W_DTH: 2.5J Q-RATIO: , G. �=' Q(CFS) HW{FT} FW ELEV. * N-FAC DC DN TW DO DE HWO H;�= *******�*+x*�**x***+***x�*�*x**�x**�***�x*�***�**�****x+***x*x*x�***��*��*�*,> „ ,.- , � . _, ,. , , � . _ _ � _- _ �_ _ �, __ � � , - �= __ __ �- _.� ., � � �-- - __ � __ � � � ' � �B 11 -� CB 13 F=2E '�u. °: JUNC N0. 9. �,L_.=�..., -_. �.... �.. �_r�� . 4., ��._ �__ , i�__�=. � . � Y-�_�.I�,.. .. Q{CFS) HW(�T) H"Vd ELEV. � N-FAC DC DN ^_'4rT DO D� HWO H?'� *x****��*�******�**x****x*****x�**x***x**x***x*******�*�***********�********_ l. li O. F- �9' . - _ _ , �__ � ,F ��. � ' . �r �. c� n +,T�� CB 13 � CB 1 PIPE N0. 10: _�� __ - _� �_ _ _ . �_ � �. __�: . �-- JUNC NO. 1C: OV�RF:�OP�-Ei: 398.36 SENJ: 90 CEG = Q(CFS) H6V{FT) ?-I�J EL�'V. * N-FAC '�C DN _ ****+*****�******x*********x*******x*******x*�*x**�. . . . . . . . . . . . . . . . . . . . . . . 1. 17 0. 65 395.51 * 0.012 0.40 0.33 0 . 61 0. 61 0.46 ***** G. _ CB 14 � CB 15 PIPE NO. il: 3i LF - 12"CP @ 1. 00$ CUTLET: 39� . 86 INLET: 395. 1? INTYP: 5 Q (CFS} HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ********x******x*x*�*�*******+*****�+*�*x**�******x*x*****�x+**x***:******+**** 1.05 0.47 395. 64 * 0.�12 C. 44 C.36 0. 65 0. 65 0. 44 ***** 0.97 B�CK_��'�TER �OC�iF;;T-R PB.OG�.T_� F�� =IP-v i �ipe data from file:a2.bwp Surcharge cond-_tion at ir.te�n:ec�a�e jLnc�icns �'ai-water Elevation: 384 . 96 feet Discharge Range:0.48 to 0. 48 Step o= 1. [cfs_ �ve_rrlow Elevat-on: 399 .22 feet �i�eir:'��CNE ri��s'rea� .�locit'.':_ . te��/sec CB 2 � CB 3 >;PE NC. 1: 93 LF - 12"CP @ 7.45g OUTLET: 382.79 INLET: 389.72 INTYP: 5 �� fCFS) HW{FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI x*f*�*��*****x***********+�************+*�;.�xx*�***�**x**�***�***************** �. 4.. � . �� '� . ` ., • --� .., . �. �� . _� � . _ _ . _ �� .�� x>xx= � .GL Pipe data from file:a3.b.: Surcharge condition at ��_=r_��-:�.�;-�_� ��u__c=__ Tailwater Elevation:385.04 feet Discharge Range:0.48 to 0. �= Overflow Eievation:392.25 f� yTPl'.�'�`'��\_ l..tS �z � l.�� FIPE N0. - - Q(CFS) HW(FT) HW E�EV. * N-FAC DC DN TW DC DE HWO !:. **+**�k ir�F�k+d-#k�kx*+c:k�k+x*i�*�Ff�k�.k**#i.*#�lrx*�ki.-+**+ir�4 i-k+x�k k�k*:Fxx�k�i*ac�c**x***#ir�k**x�+ � BACfCY]ATER CO�PUTER PROGRAM FOR PIPES Pipe data from file:a9 .bwp Surcharge condition at �ntermediate junctions Tailwater Eleva�ion:385.76 feet Discharge Range:0.79 to 0.79 Step of 1. [cfsj Overfiow Elevation:366. 63 feet Weir:NONE Upstream Veloci�y:3. =eet/sec CB 8 � CB 9 PIPE N0. 1: 31 yF - 12"CP @ 1.00$ OUTLET: 383.73 INL�T: 384 . 04 INTYP: 5 Q(C�S) HW(FT) HW EL�V. * N-FAC DC DN mW DO DE �WO HWI ****+��*+*****�**************�****�x�**�****+*+*�*+�*****�**�*+**�*******+****x 0.79 1.74 385.78 * 0.012 0.38 0.31 2.03 2.03 1.74 1.62 0.37 II .., `�;•. ;-:-: I �: ��:��"; �� ,I �I �:�, i� � � Pipe data from file:a5.b:. Surcharge condition at i:,=�r:�:`:i-�� .:_.c�-_ Tailwater Elevation:390. 97 feet Discharge Range:0.86 to 0.��= Overflow Elezration:393. 51 r�- W2ir:_.�,:�' Gpstrear. STelocit. CB 11 � CB �2 ' PIPE N0. 1: �� - - : -- _ . _ _ - -- -- _ - . � _ � - --- • - - • -- --- . �_ . _� .:_ �_ . Q(CFS) HW(FT) Hin' ELEV. * h-FAC DC DN TW DO DE HWO Hti^�I ****x*************��+*x**�x**x*�**x*x***+,�*****x****>**x***x�*,�x**x�x�+�*+**x�� C.86 0 . 65 39u. 9? * ., .��1� C1. 39 ., .3? � . :G 0. 9c' C . oS 0. ��' 0. 4C B�=,CK�^]F��E� CC.?UT'ER F:.�;;:F�=i[•] =C:�: PIFL� Pipe data from fi_e:a6.bwp Surcharge condition at -�nterme�:_�� - ..��_�:.� Tailwater Elevation:385.31 feet Discharge Range: 0.�3 to 0. 43 �te_ �.� "� . _- , Overflow Elevation:386. 96 fe�t Weir:NONE Upstream Veiocity:3. fee�/sec CB 6 � CB 26 PIPE N0. 1: 106 LF - 12"CF @ O.�G� C(i'I�E'_': 383. 17 IN:�ET: 383.?0 INTYP: 5 JUNC NO. 1: OVERFL06ti-�'<,: .i8 i . ly BEA?D: 0 DEG CII,/Tn'I1�TH: 2.5 Q-RATIO: 1.39 Q(CFS) HW(FT) EW ELEV. * N-FAC DC D?� Tw GO D� H�r10 HWI *�*+*****�*+***�x*;.�**�*****,.**��**;.*�**x*******,.******+*x***+**+**�****�*��*�* 0.43 1. 64 385.34 * 0.012 0.28 0.27 2 . 19 2. i4 1. 63 1.64 0.37 CB 26 � CB 27 PIPE N0. 2: 30 �F - 12"CP '� 1. COo O:;TL�"I: 383.70 INLET: 384.00 INTYP: 5 Q;CcS) Hw{FT) HCn� E�EV. * N-FAC �C CN TW DO DE HWO HWI x*************�x�*�**�x*�x�+******�****x**=x***x*x*x**�*x*�*x�***�**�*��+�**�* 0. 18 1.34 33�.3� * C. 012 O. =B 0. 15 ��. 64 1 . 64 1.39 1.20 0. 15 Br�K�nH�ER CC:•iPU�ER PROG�=,f<i FOR: PIFE,� Pipe data from file:bl.bwF Surcharge cor.dition at intermediate junctio=�s Tailwa�er Elevation:389 . 6 feet Discharge Range:2.1 tc 2. 1 �te� cf l . ;cLs] Overflow Elevation:396.66 fee: We�-r:NON= C�pst�ea�. .�locit� . �. feet,�sec OUTFALL � CB 16 PIPE N0. 1: 35 �F - 12"CF @ �' . b5=� �:;TLET: �?�. CC1 ITdLE=: ?�5. �� IN:YF: 5 �UNC N0. 1: OVERFLOW-EL: 396.08 BEND: 0 DEG DIA/WIDTH: 2.5 Q-RATIO: 0 . 41 Q(CFS) HW(FT) HW ELEV. * N-FP.0 DC DI� TW DO DE HWO Hin'= *x*+*******�x*�**x*****x*�**�**+*****�**�*****��***+***+**�********+****��*+*,.x � . 10 ,, . �� cE �� * ��.C_2 O . o'2 �� . 31 . . EO 5. 0�� 0. 52 �*'x+ ., . 8? CB 16 � CB 17 PIPE N0. 2. 1-1 �_ - -� �F '� .. . . �� ---T. __`_ . ., . __.��_. .__ . �- =ld:'Y_ . � JUNC N0. 2: OV_R.FLO�^i-EL: 3:i . 45 B�ND: y0 C?G DIA/U�IDTH: 2.5 Q-R�TIO: C' . Q(CFS) FW(FT) HW ELEV. * N-FAC DC CN TU; DO DE HWO H; *********�*x*�*****x+*��x�***�*+��*��*��*********��x***�**�****�*+**�**�**+*_ 1.49 0.74 393.41 * 0.012 0.52 0.27 0.8? 0. 87 0. 52 ***** 0. �4 CB 17 � CB 18 PIPE N0. 3: 49 LF - 12"CP @ 1.00° OU"LET: 392. 67 IN�ET: 393. 16 INTYP: 5 JUNC NO. 3: OVERFLOVJ-EL: 39E. 66 BE?�D: 9C DEG CIA/WIDTH: 2. 5 Q-:2ATI0: 0. 05 Q(CFS) HW(=T) Hw E�EV. * N-�AC DC DN TW DO DE HWO HWI i:jr-k*i-*Kk�,k,�*-k 1�k1.(-k,F�.��*�-.�r�r:x,...-41#�.��1T , ,.��x��-+1-k#�i.-��t�t+t i��+T�F�,i��T+�,��A 1- B.4'_,K"JrI'L3 .,0"_ [�1�R. �?0'.��i-'"' _ .," _I -.. Pipe data from file:cl.bwz Surcharge condition ac in�e-r�,ed,�ate jLnctio~� Tailwater Elevation:375.3 feet Discharge Ra�ge:0. 95 to 0. 9� L_-. __ _ . ==s; Overflow ElevGt_on:382.69 feet Yd e i r:t�I�N� rl��=_eG_rr� . �l��it�-. � . _`e�=.'s�� EX. CB -� CB 25 PIPE A0. 1 . 8_ L� - _�"�_ � � . _�: �;;---- . � . . �C -_:LET. _-B . �G IPd.'i_ . � JUNC N0. 1: OVER_LOi�7-E�,: 383.00 3END: 9� GEG DIA/✓�'IDTH: 2. 5 Q-RATIO: 0.0� Q(CFS; H�ni(FT} HW ELEV. * N-FAC DC DN TW DO DE HWO HL�,_ **+***�+�**********��x*****<*��***�****�**x�*********�****�***********x***x�x_ 0. 95 C . �6 � _ . �� x _ . �__ _ . -, n. _� _ . CC : . �� . . .1 .��*_ n . �6 CB 25 � CB 24 PIPE N0. 2. �� =,F - __ �r _ 1 . .,�� „J'��_: . . , � . 5� =�:LJ_ . 3-.. . �6 ir,�'Y�. 5 JUNC NO. 2: OVERFLO�r]-EL: 382.70 BEND: 90 DEG DIA/47ID�H: 2.5 Q-RA,IO: 1 . �� Q(CFS) HW(FT) EW ELEV. * N-FAC CC DN TW DO DE HWO I'.r;�I ****�******�*�****x��x***x**x*,:*****x**x*****x**;.*****x��*�*��**��*�****�+._� �• `'� � • � - - • �- � • -- - - - . -- � . -r _ . �_ • - :�_��,. � . �� CB 24 � CB 2� ?IP� N0. 3: = - — - -- _ - • - _ - • _ • — _ . -_ _. _,. - : • _ Q(CFS) HW(FT} :iN7 ELEV. * N-FAC DC �N TW DO DE HWO H�•. : **�****x**x�******�****x*��**�*******��*�x*�*******��****��**�*�**�********�_ - . �_II � City of Renton, Washington � � Sto��m D��ainage Report 1 � i � � . � Prepaj"eG� I�J�: � ENGINEER'S STAMP NOT VALID Brett K. Pudists UNLESS SIGNED AND DATED I � A� REFL �P� OF w�sk,�F `�' aJ' Reviewed by: " � o � Mark A. Reeves, P.E. , a�� '�� _ o �,� zoao, o` ��`.., ' � � S`S�ONALR��G\ EXPIRES: ��26/ ' �:•s �� — �� I _� �� TRIAD ASSOCIATES April 6 , 1998 Triad Job I�1o . 97 - 006 j � ARCH CUL VERT 9 In the developed condition, S. 47`� Place will be placed in the path of an existing drainage t course. An arch culvert w�as sized to convey flows associated with the swale underneath � the proposed roadway. � The culvert was sized to convey the peak rate of runoff from the 100-year, 24-hour design storm event. The flow was estimated using Engenious Systems Inc.'s hydrology program � Water VVorks. Hydrographs were developed, based on S.B.U.H. methodology, using a King County Type I-A (ITser 1) 24-hour rainfall distribution. Separate S.C.S. curve � numbers were used for impervious and pervious portions of the basin. Please refer to the Upstream Area Exhibits located in the appendix of this report for basin delineation. A � surnmary of the flow estimate and culvert sizing process is provided below. � Area Tributary to Arch Culvert � � , The upstream soils belong predominately to hydrologic group C therefore runoff curve numbers were chosen accordingly. The impervious area for the upstream area was ,� conservativel estimated assumin it would be developed at the same densit as the Y g Y � "Fredericks Place" project (see Upstream Area Exhibit). The Fredericks Place project was developed at approximately 4.6 DU/GA which cotresponds to 47% impervious (see � Table 3.5.2B in appendix). Refer to the Flow Estimate exhibit for actual computer output. .� Tota] Area = 38.90 Ac � � Impervious Area = 18.28 Ac @ CN- 98 (roofs, pavement) Pervious Area = 20.62 Ac @ CN- 86 (landscaping) ■ - ITime of Concentration = 5.0 minutes (conservative) � �I I00 Year Pcak Flo�ti�=32.62 CFS � STOR1�1 DRAIl�iAGE REPORT FOR TALBOT RIDGE-PAGE - 25 � i � Arch Culvert Sizine Based on the nomograph for Corrugated Metal Pipe-Arch Cuh�erts (see �'omograph exhibit and Arch Culvert exhibit in the appendix) a 50" x 31" arch culvert has a flow area of 8.7 square feet and can convey the 100 year peak flow of 33 cfs with a headwater depth of 3.33 feet [0.9 x (31" x 1'/12")]. Due to product availability, a culvert with a slightly larger flow area will be used. As designed, the arch culvert will be 49"x 33"with 8.9 � square feel of flow area. � RELOCATED S�'�'ALE The existing drainage course will be relocated just west of its e�cisting course. The .� relocated swale was sized, using Manning's equation, to convey runoff from the 100-year, � 24-hour design storm event (calculated above to be 33 cfs). Manning's Equation: 1.49 , � Q = *A *R� *S�: n Where: n = 0.030 (roughness coefficient-grass lined sx�ale) J s = D.01 (minimum swale slope) A — 8.042 square feet Q« = 33 cfs , As designed, a grass lined swale having a three foot wide bottom, 3:I side slopes, and a nunimum botion: slope of 1.0% can convey the required floiti� of 33 cfs witli a floiv depth oJ�approximalely I.2 feet (A=8.042 square feet). , STORM DRAINAGE REPORT FOR TALBOT RIDGE-PAGE-26 - -..i�::y'�:. ` . �. ". V -..� . 5 AREA TRIBUTARY TO GULVERT = 38.90 Ac AREA TRIB. TO DETENTION PIPE = 2.68 Ac� _ � . ... � � CULVERT , � � �. � , �` PL �, -. � i, 7 40 � . � • . 19 � . � � � � T�e°f Conc. �_ � � � 13 12 11 \. �� _� Y . 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' ` �^ � �` UPSTREAM AREA � �� g S.P. 383067 j: — �e 5-� _ EXHIBIT - ' - �e�o� - . � s � �, -� r�� .5; ',ISC V � g I� _ 2 �,�„ � � � -?.,� l 2)� ` i _�8 . � ; l3) � - �� i .tit �`�'-`-/ri sy� 'p' - -- ` \ �. . � P�'1 CD �—��.n 9+ ? o � i _k./ "�,� S� I � P�EI.-I1�ZI��1�i�Y S�'OR.�'�� D1��L�T�GE REPORT FOR STONEHAV-E�T RENTON, �:qSHINGTO\ � � _ �, �,t'� `��Y��Ch� �� V�P�`d°f =� �f'��, � � � ��u- L� 3 tn ," ��7 � i� �% � '.J�'� 39it30� �,� .r�, �'Cd$TE�:.r,�r�o i ! / �'�L'"d�Lr%a� , ! Prepared b��: Stacia K. Schroeder, P.E. � ' J a ExF:R.s 5-2'- G� , Revie�i�ed b�': David E. Ca�rton, P.E. Date: Januarv?004 ��`�� Core No.: 03095 STONEH�VEl� TABLE OF CON'I'ENTS I. Project Overview II. Existing Conditions Summary III. Off-site Analysis A. Upstrearn Tributary Area B. Bypass Area C. Do�unstream Analysis I`'. Developed Conditions Summary A. Hydrolog-ic Anal��sis B. Detention Routin� Calculation C. ��'ater Qual_it�� 'olume Calcuiation �,_� Coi�e Desian. Inc. Page 3 I. PRO,�IE�CT OVER`TEa' The 59�2ac Stoneha�c�en site is located on the southwest comer of 102°d Avenue SE and South 47`h Street in Renton, Washington (see the artached vicinitymapj. The project includes 2 parcels cor_sisting of 3 single-famil��residences and miscellaneous outbuildings. The existing�ound cover is a combination of impervious surfaces, 2,nd erow-th forest, grasses and landscaping. The site does receive a sma11 amount of upstream runofi from unplarted parcels to the south. Also; 12" and 24" storm drain lines currently enter the property along the southeastem boundary and discharge immediately to an existing drainage su�ale. Due to a critical wetland area in the southwestenn portion of the site only 5.712 acres of land will be developed. The proposed project inc?udes constructing 36 single-family residential lots with associated roaduTaS�s and utilities. One of the existinQ residences mentioned earlier will remain on Lot 24. Half=street improvements, including road��ay widenin�, curb, gutter, and sidewalk, ��ill be macie�0 102n�Avenue SE along the property's eastem frontace. A 5' sidewalk will be�e only addition to South�7`� Street along the northem boundary (see the attached Site Plan). The on-site generated runoffwill be directed to a com�ination detention;`wet pond located within a storm drainage easement in the northeast comer of the property. The aforementioned 24" storm drain system will be routed ar�und this detention facility. All drainage discharaing from the pond and the 24" bypass line v��ill pass undemeath South 47�' Street via an e�isting culvert and continue II dow�nstream. � The Stonehaven project was designed using the guidelines and requirements esiablished in the following references: 1990 Kin� County; Washington, Su.rface Water Desi�n �I � '_Vlanual (90 KCS��I}?v1), the city ofRenton De��elopment Re�ulations (1998); and the City of Renton Standard Plans for Road, BridQe, and Municipal Construction (1997). i Core Design, Inc. Page 3 i � W � � � Q � � � 1s7 � o � � �' SE 172nd ST � 515 � � I � Rp SE SE 176th ST Va//ey �PRR I Medicol s �rd sr Center ��9{h ST c� SE � � SE 182r,d S T 1 S� � 0 s 4�th sr ^ � SE 186th ST � � j I � � � SE 187t�cW I' � o � 0 v � Q rn � Q � 3 > � � i I S 55th ST " ^�' SE 192nd ST il I � � I I V/C/N/TYM,4P � ' NOT TO SCALE � �I GURE I : VICINITY MAP f�ATE JANUARY 2404 14711 NE29th Place Surte 101 Bellevue, Washington 98007 ' �KAWN SKS 425.8857877 Fax 425.885J963 APPROVEO �Ec DESIGN PROJECT MANAGER ENGINEERING • PLANNII� G • SURVEYING �Cing Counfij ��partrr�ent �i Develcpment and.�nvironmental Servicas $ .-��.a.��3�Q��'e�. ��a��i i�� 3��9 �� ' Patt.'1 PRO.iE��T ONlNER:AND� Far:2 P.RCJE�� OCATiON AND i �RGJECT=EiVG1NE�P, I DESCR1PTlOf�1_ Projec;Owner , Projec: Nam Stonehaven -na�� a�a� v Address Location I - - �902 Bigelow Ave. N. , Apt 402 � ' Seatt e, WA 98109 Township 2� N- j 1 Phone i?ange 5 �' I I Project Engineer •-----.......Se�;ion 32 I �ave Cavton, P.E. i I �ompany Core Desian, Inc . � � ?.c�dress/Phone 425-885-7877 � i '�art 3 =::TYPF-OF,P.ERP�tf i Part-4 .OTHEt-�. A�1IfPNS AND r'?ERN11T5 � � � .:�R�LICAT]OP�::. �.� � Subdivison I � �F1N HPA Shoreline Manaaerne�t 5hort Subdivision � CCE�04 Rcciczry I Grading COE Dam 5a;ety Str�.�ctur�I Vaults � � Cammercial I . I I F�MA F��captain Other ' Other � C�E 1Netlards { � L I Part 5 ..SITc�i,JI1litvlUNtTY AlVD-DRAIfVAGE BASIN ; Communiiy � �cx�� C'rPPk � Drainage Bas' I C�reen �iver / Black R-ver Sub—basin ; Part:6: S(TE:CNARACTERISTICS ' River Roodpiain � Wetlands Yes I Stre2m Seeps/Springs i Critical Stream Reacf� High Groundwater Table De�ressions;Swafes j Croundwater Rec7arge Lake � Other swa� P Stee� Slopes Part 7- .:SOIL:S _ i Soil Type Slcpes Erosion Potentia� � �rosive Veicoties �.1 r�Prw��c� F-i ;, moderate --- � i . i , Additional Sheeis Attached � Pait 3: DEVE`OPME.'VT L]M1TATlONS � RE:=ERENCE L1MITATIOiV/51TE ;ONSTnAINT I Ch. 4-Downstream Analvsis none � i � 1 I , , � i � � Addiiiora? Sheefs Attact�ed ; ( P�rt.9 .;�'�C RF{�U[REfidE.?�ITS . ' }VlIN1tV1Ul1ri ESC REQUIRElIr9E1VTS iV91NtMUM ESC RE�UIRFJ4IE�lTS � GUP,ING CJNSTRUCT]ON AFi Es-'? CONSTRUCTIGN i XXSedimentation Faciiities �5tabiiize Expose�' Surfac� i �gStabiiized Consiruction Entranc� �Re!riove an� Restore Temperary E5C Fac:lities ! ! ggPerimeter Aunor Control �C1ean and r�e�nove All Siit and Debris �Clearing and Graing Restrictions xxE:�sure Operation of Permanent Facilizies ' XXCover Practices �Flag Limits of SAO arid open space �kConstruction Sequence preservation areas �th� Other ��Part i0 SUFFACc WA,i Et� SYST�A I Grass Lined Tank Jntil,ration �;X Me±hod of Analysis � Ctianne! KCRTS/SBUH Vauii Depression i XX Fipe Sys,em Comper�.sation/Miticati Energy Qissapato� �low Dispersal - or, o# Eiiminated Siie I Ooen Channe! ' Wetland Waiver Storage i �XX Dry Pond Stream Aegional i XX Wet Pond Detention I Briei Description oi System Operation�,� ra ��a�,��.�;�,...�,�.�.e��.��-�� i detention . /-::water qualityl pond I Fac:iity Fielate� Si�e Limitations ' Reierence Facility Limitaiior, Inone � � I � Part�; STRUCTtJAi4L A�°VAL`!SIS � Pa�t 12 EFiS�MENTS/i R�,CT� Ca_si in Place Vau[t D�ainaae =as�ment � Retaining VVaf1 i Ac�ess Fasement i , , . Rockery.>4' Hioh Nafive Growth Prot�ciion Easement . I Siructural cn Ste�p Siope XX�'�� wetland and. storm d.�� j �t�l@� � �if1BC � �arf:13. S1GN/�TURF.OF PROFESSIt3�1AL EiVGINEE:� � I � i or a civii engineer under my supervision my supervision have visited the siie. Actual siie I I conditians as observed were incarporated i�to this workshe�t and the attac�ments_ To the best fl� ' I my knowiedge the information provided here is accurate. I ', i I ( Sivned'Date i�31 . . . �.J 1 V��'1�� ♦�` \T �h��'9� �l' ��V��'1\�� I. Pro3ect Overvie�� II. Existing Conditions Summary- III. Off-site Analysis A. Upstream Tribuiaz-y!�rea B. Bypass _Area C. Downstream Analvsis N. Developed Conditions Summar,- a. Hydrolo�ic Analysis B. Detention Routing Calculation C. «%aTer Q�wali�- �"oiLlne Calc,,�':anon Core Desi�n,Inc. p��e �' TI. E�STI?VG CONDITTONS SL�TVI_ARI' The existin� site is co�-�rec b� G colnbi�a;:on ot�e�-ious and irr.pen�ious suriace:, includin�: second grow�th forest, buildings, paved and graveled driveways, lawn and landscaping, and a small wetland. The site soils are classified as Alder«�ood Series, ��C (see the attached Soils Map and Descriptionj. An undefined rid�e separates the onsi�e runoff into several directions. Mainly however, a small area (0.584ac) is directed to ar existing wetland in the south��est corner of the property and the remainin� area (�.128ac i collects in the onsite drainage swale either urunediately or within 1/4-mile downstream of �' the site (see Downstream Map I�o. 1 in Section IIl�. There is also a sma11 amount oi upstream area(0.447ac) and a 24"bypass line associated with the project (see Sectior_ III—A &B). Using the Seasitive Areas Map Folio for Kina County, December 1990; no ; other hazardous areas (seism�c, erosion, Iandslide, l OQ-��ear floodplain, coa� inine;t `�-e:e identifi�d. Lore ll�.i«n.Ine. �'.. � � �� 'r�o / .I� �5e�'. mi /,� _ \ � / U' I� •�f� �/;ii�'��' I Pr� _`�� _ . --�".,1------ ---- '----� —iz_� 1�A, Iur e J ! ; � , l �— � ', I .�R 54,�0�� :� � o � . :, ,,.� I l W n, ((`` � 1 / �` � 1 � W �;°• \• hi I "y � S� T� Z D �� ,i\�� m z I / Pu + m Sk 1 �� !\, � c � , � r,+ � � I ,� 1, '; � I �0 ( __--�- olE� E � i `' ,E9 ,z�.� �� _.. � � I ask : . � , -/. � / (�..'II� . ; �� T� ��:: � � , � �. A, �. � l� �,;i_J�..I In/� �q� /� I So ! . �� / ':� �______ �=____= L---� --- � ..��1�� . ,,,_. i w4 a� �Mc 1 I - : < < �� .��,: ►- - - _ � - � l - , �� - „ :�� - �--� � scAi�: t- _ ��' \ I . - ... � p �} „ �. �- � i�oo 'ooc •aoo .,9,� _- - � �•; I,� �o c � i � �8� .r a� � � � � U r t. \-B ��C. �� _pgC 9' e ° __ —.r� � I` i� i�~ _ .� 1 � : ��- _ I •�` - `-__ � Br I Re- : � �I - �. r.Wo c� J � .. A � . � py. ; �,., ,. r as :. . � - �� s« so :. i \.' � . -- � 1 � SHEET NO. I1 � --o , i . • � _ � Ma • --- ._�, t� KING COUNTY:�RE?,, WASHINGTON �•1 � a� � �/�,' g '�, �; 1 (RENTON QtiADRANGLE) � o'l�� •� 9 ' ' � '� �� 0 '� -` l�.� '� i . ��. S. DEPARTn�'_VT OF AGRICtiLTURE � : P� � ��°a� �� i CJ SOII, CO�rSERV?,TION SERVICE � i� � ( AkF\ � � t ,; �' o �` :.� �Dnve-i '\ � .Ji,.�� I � �� 'Theacer ` � \. 8.� �vYo ,j I� ii`�.� . . ,��C �� ia-i;Ne< mvie«, rc� 8 i ,i°� A s�;��.,,�.wo,n�s�, ?aco? ;I �'f e � � j ll � . ' � �O� t<5.685.78.7 Fcs 4<'S.SHSJ953 � !"_= OS �10 � � �� am�� AnC ��ESlGN � � � � ' i � , ''•-' . . � 1� + I �' E.4',.,rNc=4�N.� ?.A.Y.N;NC- 5'JRvf �rvC- � �. � l �I ` ', 1 �7• ,. �.:; :y. � i � � f ' 7 � i 7:. i � 8� ' �:�\'i.�;�� :� _ S/ TE SO/ L S M .�. F' .er ; �� \ .- .. � - ;�, f�� ;;��r.,,�: �-, S 7-O N �H /-� �/E/�l � I;7�� `-' ��'+f ;li S T E �./E N B E C K u� I� `^ � � ''_`' �f�` ' �;'� 19129 SE 145TN STREFT 1 ' I ''`` � — '.�',�� ' "`' ` . T� � `; '�� RENTON, WA 98059 D A.TE JAN, 2004 S H E�� I O F DESIGN�C DEC 1 i 1 �rAWti SKS �,'�OJEC- ti',JP.�BER 0300� DESC�IPTIONS OF T�iE 50TL5 Tnis section describes the sci_ se-ies and map- Alderwood soi_s are usea =or t_mber, pas�u�e, ping �:iLs =r. �he King Cour:�;✓ A.rea. Fach so_i berr'_�s, rcw �rops, and urban develepment. They series is desc=ibed a^.d then each ma�ping urit i�? are t1-:e most extensive soils in tae survey area. that series . Uniess it =s specif_cally mer.tiored � othe�-�+-'se, _t _s tC �e 355llP.!e� tt;d+ 'nt:3t 15 S�dted F�_Qe�'OOC �T2Y2�Zv sandy lcam, 6 '_D �� pET�2Pt �bout the soil series nolds tru� �or tne m2pping =_l�pes (?;gCl .--"'his soil is roil�ng. Areas are units ir. tnat series . Thus, �O �Et LII1� inro�ma�ion :rregula_ in sh2pe and range from 10 to zbout 600 about any one mapping ur.��, it is necessary to reac acres i� size. both the descr'_pt�on o� the �apping unit and the Represer.tative prof_le of Alderwood grave:ly descr-ption of the soil seriFs to which it belongs . sandy loam, 6 to 15 percent siooes, in woodland, .Sn import azt p�rt of the description of each 450 feet east and 1,300 feet sout:� oi taa nerth soi'_ serie= is the soil profile, t'�2t is, tne quarter corner of sec. 15, T. 24 N., R. o E. : sequence of layers from the surface eowr.ward to rock or other underly_ng naterial. Each series P.'--0 to 2 incnes, very dark bro��m (�OY'R 2/2; contains two cesc_iptions of �h�s prefiie. The gravelly sar;dy icam, darx gr2Y�sh orown first is br;ef anc in terns tamiliar to the layman. ;1Q`.'R 4/2) dry; weak, fine, �ranular struc- The second, detsiled and in technicai te�rs, is fcr ture; slightly hard, fr_able, nonsticky, sc_entists, engineers, ar:d others who r,eed to inake nonplastic; many root=; strongiy acid; tl:orough ana preci=e studi=s or soils. Unless it abruat, wavy boundary. 1 to 3 inches thick. is otherwise stated, t:�e colo_s g�ven _n �.he B2--2 to ;2 inches, dark-brown (lOYR 4!3) graveli;r descriptions are thcse of a �ois� so_1. sandy loar.:, orown (iOYR 5/3) dry; mocerate, I As mentione� in t'r.e sect_on "How This Survev Was meditun, subangular blocky s�ructure; sligntly Made," not all napping ::nits a=e members o; a soil ha_d, friaole, nonsticky, aonplast_c; mar.y series. Uro2r_ land, for ex2mple, does aot belong roots; s�_ongly acid; ciear, wavy bound�y, to � soii series, bu� r.evertreless, is listee in 9 to 14 inches thick. zlphabet_c orde_ along with tne so�� series. B3--1Z to 27 irche_=, grayish-brokm {2.5v 5/2;� Following ti�e name o� each ma�ping Lnit is a gravelly saz:dy loam, liohz gT2y (2.5Y ?;'Zj sy�bol ir. parentzeses_ Tzis symbol identif_2s the dry; many, mecitrn, eistinct mottles o� _i�r� mapping unit on the det2iled soil map. L�sted at oiive brown (2.5Y 5/6); nard, friable, non- the end of each descri�tior of a mapping unit is the sticxy, nonplast=c; many r�ots; nedium acid; capa5_lity unit and woodland grou� ir: which the abrupt, wavy �oundary. 12 to 23 inches thic::. mapping :u:it �as beez �laced. ;7�:e woodlane desig- _IC--2,' to 60 inches, gray_sh-�roar. (2.5Y �/2) , nation and the page For tl:e description ef each weaicly t� s�rongly consolidated ti11, light cap2bility snit ca,� be found by referring to the g�-ay (2.5Y 7!2) dry; comr,ion, medium, disti�c- "Guide to Mapping Units" at +.he back ef this survey. mettles o� ligh� olive bro„m anc yellow_s=. The acreage �nd �roporticnate exte�t of each brow-n (2_5Y 5/6 and lOYR 5/6, ; mass_ mapping un_t are shok�r _n t2b1= 1. Mzny of the roo�s; nedium ac_d. Many feet tliic: terns used =r. descrzbing so_,s can be founC in the Glossary at the end of this su_��ey, and mcre de- The A horizor. ranges from verv dark br� tailed irformation abo�t the te�inology ard nethods daT!c broun. The B horizon is dar:c brown, o_= __.. o_ soil mapping can be obtained frora the Soil Survey brown, and dark yellowish brown. The consolidat�� Manual (19) . C horizon, at a depth of 24 to 40 inches, is mos�'�; grayish browr_ rottled with yellon�ish brown. Some Alderwood Series 12yers in the C horizon slake in water. In a fF��.� areas, tnere is a thin, gray or grayish-brown AZ The Alden�ood series is made u� of moderately horizon. In most areas, this horizor. has been well drained soiis tha� have a weakiy consolidated des�royed :nrough logging opera�ions. to stror�gly consolidatec substrattun at a depth oi Soils ir:ciuded with ��is soil ;n mapp�ng malce np 24 to 40 incnes. These soils are on upiands. They no more tnan 30 percent of the total acreage. �ome formed under conifers, in glacial deposits. Slopes areas are up to 3 percent the poorly drained Norn:a, are 0 to 70 percent. The arnual precipitation is Bellingh a-n, Seattle, Tu]:wila, and Shalcar soils; 35 to 60 incnes, most of whicl-. is rainfal=, between some a_e up to 5 percent the very gravel�y Evere�� October 2nd May. The mean annual air te�pera�ture is a�d Nei'ton so;ls; and some are up to 15 percent about 50° F. The frost-free season is 15C to 200 Alderwood soils that have siopes more gentle or days. Elevation ranges from 100 to 800 fee�. steeper tnar: 6 to 15 percent. Some areas in New- In a representative profile, the surface iayer c2stle Hills are 25 percent Beausite soils, some and subsoii are very dark brown, dark-brown, and nor�heast of Duvall are as m�:ch as 25 percer.t Ovall o ayish-brow•n g_-avelly sandy loan abou� 27 inches soils, an3 some in the vicinity of Dash Point are thick. ihe subst,atum is gray�=h-brown, wezkly 10 percent Indianola and Kitsap soils. Also consolida�ed te stron;'�.� cor.=elida�ec oiac_a'_ till ir_c;�ded are s�a_. �reas of .Slder„�oo3 soiis that -_ th2t extends to a de�th of 6C ;-�c:les an;: rrore. 3=�;'e � �_a�.-e�l:: �o�n surtace la;-er and s�esci_. � PFrmeability is modera�ely rap_d in tne surf acF .Srents, .Alcerwood Mate-ial layer 2nd subso_1 and very sl�w ir. the subst=atam. Roots �enetrate easily to the consolidatFd substr2- tum where they tend to mat on the sLrface. Some Pser.ts, Alde=woo? material �onsists of .Alder�.�ood roots enter the subst=a�:am :hrough crack=. h'2te= so'_=s �hat have oeen sc dis�ux'bed through urban- moves on tcp of the sub=_tratu,-n =n winter. Available _za�_or. +.h a' th�y no ior_ger can oe classified with water capacity is low. Runof_' is s_ow to med_un, the A'_ce=-wood s�ries, The=e soils, howeve_, nave and tne haza_d of erosion ,�s moderate. many sim=lar fe2tures. The upper �art of the soil, This soil is used for timber, �asture, be=ries, t� � deptn oi' 2G to 40 _nche=_, '_s brown to dark- and row crops, and for ur'�an development. Capabil_ty bro�r. gravelly. sandv lcarr�. Below t�i_= _s a gray;sh- unit IVe-2; woodland group 3d1. � b_oh�, consolidate� 2r_d _mpe�r_ons suostratur,i. Slopes general7.y range =rom 0 to 15 percent. Aiderwood graveTly sand,v loam, 0 to 6 pe_ceat '?�},ese soi;s are usee for nrbar. deveiopment. slopes ,AgBI .--This soil is nearly leve'_ and �-- undulating. It is simi_ar to Aider�aood gTzve_ly sand,v loam, 6 to 15 percent siopes, but in pl2ces �qrents, Alderwood material, O to 5 perc�nt slo�es i�s sLr_ace layer �s 2 io 3 inches tt:icker. �;reas are i=regular in shape ar.d range from :0 acres tc �'`�`�� •--lP r�any areas tnis soil is level, as a result ol shaping daring construction for urban slightly more Lhan 600 acres ir size. , facilities. Areas are rec�angular in shape and Some areas are as mcch as �5 percent inc_uded range =rom 5 acres to about 400 acres in size. No:-m2; Bellingham, Tu}:�,��ila, and Sna_car so_is, all Re resentative roriie oi ?sents Alderwood of which are poorly drained; and some areas i-� the p p ' vicinitv o� En•,�clai+� are as much as ;0 �ercent �a�er_al, 0 =0 6 percen� slopes, in an urban STe3� - 1,30C feet we=t and �50 fee� south of �.he nort�e�t Buciciey soils. cor:ier of sec. 23; T. 25 N., R. � E. : Runo�f is s1oH�, and the erosion hazard is s'_�ght. G to 26 '_nc'�es, �ark-orown {lOYR =!/3) g=avelly '�is Alderwood soil is used �or �imber, oasture, sandv loa-n, pale browr. (lOYF 5j�) dry; berries, and row crops, anC ror urhan develcpment. �;2�si�re• sl� 7�'r Lard, ver� friable, nen- Capability ur.i� IVe-2; woodland group 3d2. ' �g' �-' f . _ st_cky, nozplastic; mary roets; mzdium ac_d; .Alderwood gr2veliv sar_dy loam, 15 to 3G percent ab rspt, smooth boundary. 2s to 29 inches s'_o�es (AgD) .--Depth to the suUSiTdLllIL in this seil thicx. va=ies w�ithi� short distar_ces, but is co:nmonly 25 to 00 inches, grayisn-b:own (2.�Y 5,�2) weaKly �bout 4D ir.ches. Areas are elongatec and rar:ge consolidated to strongly ccnsc�ida�ed glacial �ro�: 7 �o about 250 �cres _n size. t�ll, lig?l� D_OkC11S}l �r2y (2.5Y 6/2) dry; Soils included with th=s scil =n ma�ping ma'se co;nmon, mediurr., pro;niner_t mottles of yellow_sh up no mere �han 30 �ercent of ;h e total acreage. �rown (iOYR 5/6j moist; massive; no roets; Sone �eas are up to 25 percent Everett soils tZat mediun acid. hlary �eet thicx. have slopes of 15 to 30 percer_t, ar:d some areas are up tc 2 percent Bellingham., Vorma, aad Seattle so_ls, The upper, �iery iria�le p.a.t of �.e so�l ex�ends wnich are in depressions. Sor�e areas, especiaily t� a de�th of 20 to 40 izches and ranges from dark on Sq::ak Mcuntain, in lvewc25t1e H�:�s, and nortl: of g�ayish brown to da=k ye_lowisn orown. Tiger �Iountain, are 25 percent Be2usite and Ovall � Some areas are up to 30 percent include3 soi'_s sc_ls. Beausite scils are urderlain by sa*�dstone, t'�at 2xe similar to this soil mate-ial, but ei�he: and Cvall soils by andesite. shaliower or deeper over the compact substratum; Runoff i= medium, and the eros�on hazard is azd some areas are 5 to 10 percent very p avelly severe_ TLe slippage potential is moderate. Everet� soils and sa�dy Indianola soils_ Th:s Alderwood soil is used mostly for tim5er. Tnis P,rents, Alde�ood soil is moderatelv �,reli Some areas on the iower parts of slopes are use3 dr2ined. Pe�eability in the upper, G�15t1Tbed soi� sor pas�sre. Carability unit G'Ie-2; woodlanc group mater_al is moderately rapid to moderateiy slow, �dl. � depencing on i�s compactioa during construc�ion. The substratwn is very slowlv permeaele. Roots" Alde_wood ar.d Kitsap soiis, very steep (AicF) .-- penet_ate to anc tend to nat on tae s�r�ace of tne This mapping unit is abou� SO �ercert Aicen.00d consolidated substra�um. Some roots enter the o avelly sandy loam and 25 percent Kitsap s lt sudstratt:r.i tnroug}: cracks. Water movea on top of loam. Slopes are ,�5 to ?0 percent. D�stri�ution �e substratt:m in winter. Available water capacitv of the soils varies gr eatly within short d�st�nces. is low. Runoff is s_ow, and the erosion hazarc i� .4bout 15 percent of some mapp.ed a;eas is an slignt. included, nnnamed, very deep," m�derately coa_se T'1:is soil is used for ::rban develonment. Ca- texturec soil • and about 10 pe:cent of some areas _ . -_ ' �a�1_�T.'✓ L'=1_r _�VB-=� 'n.COQi3RQ c:0:1�..� JQL. 15 a very aeB�7� coarse-texturec Irdiar.oia 501�. Dra�r.age"and permeability vary. Runoff is ra�ic to very• rapid, and the ero=icn ha�ard is severe tc :=._er.�s . :d��-:�ocd r..a�erial, o _o :5 �erce�t very severe. The slippage potertial is severe. slo�es (,�,-r.C) .--T.�-s soil }:as �on1�e�. slcpes. A;eas These soils are used for timber. Capab�lity are rectang�alar in shape and range fron IO acres tc unit 1��e-1; woodlzad oroup 2d1. abou` ?50 ac=es ir si-e. 1C III. OFF-SITE A��I.Y"SIS ' �. UPSTRE_��7 TRIBLTT_�RY AItEA I Tn�re is 0.44i-ac of forested upstream area tnbutary to the subj ect site in the e�istina condition(see the attached Upstream Tributary Area lV1ap j. lincontrolled sheet flow crosses the site's southeastern boundary and enters the onsite draina�e swale. The ' additional flo«�is taken into account in the KCRTS analvsis included in Section IV. Potential ups:ream ar�a fro�,: lv?�° A�-enue SE a�ic Souti7 -��`� �treet is tietained in a 36" under�round detention pipe located in the roadway near the northeastern property boundary. The outlet to this s}�stem is also directed to the e?�isting drainaae s�Tale, but north of South 47th Street. The enure storm drain analyses for this system can be faund in tl:e "102na Avenue SE (I�ear SE 185`'' Place) Technical Informafion Report" (King Cour.ty) and the "Talbot Ridge Stor:n Draina�e Report" (Ciiy of Renion). Both reports «-ere prepared by Triad Associates a:�d submitted April 6, 1998. B. BYPASS AREA Otfsite fl�w enters the site near the southeast comer and travels north, north��est for a�proximately 310 feet in an open drainage ditch. Here runoff enters a 36"hi�h X 48" «ide CMP arch culvert and passes beneath South 47``' Street. (The sizing calculations for the arch culvert can be found in the "102na Avenue SE ('�Tear SE 185t�'Place) Technical Information Report" mentioned in Section III=A). Curentl��2 se�arate deterltion systems (a�sociated �ith thz adjacent `��indsor Hei�hts project in I�ing County) contnbute flow to the onsite drainaae swale in the southeastem corner of the property. A 12" dischar�e pipe stems from an underground 36" detention pipe located in 102nd Avenue SE (similar to the detention pipe�escribed in Section III- .-�). Additionally, a ?4" outlet pipe originates from a detention pond directl_y east of our �arc�i. Tl�e �io��ra�,:e� Plst,;,�i'1 b�:��ass �r�is o_ts�te fo« a�o�rl�� t:le ne«� defe_ztion Core De�i�n.Inc. Pa�e` � � � III. OFF-SITE Al�AI.I'SIS (CONT.) B. B�'PASS AREA (CONT.) faciiity in a 24" tight-lined, closed conveyance system along the eastern edge of the property(refer to the Site Plan in Section n. C. DOR'NSTREAM AI�'ALYSIS The Stonehaven site sits on top of a bluff��ith a loosely defined ridge. Runoff sheet flo�rs across the parcel at 3% - 20%in various directions: southwest to�;�ards the onsite wetland, west towards the Talbot Ridge residential development; north/northwest to an offsite steep sloped area; and eastinortheast to an existing drainage swale. The majority of site runofr''ho�z�ever is directed to the north and east {see Drainage�Vlap No. 1) and enters the onsite s�;�ale either onsite or within 1/�-mile downstrea�-n. Roughly %-mile dov��nstream, the s��ale (labeled uibutar�� 0010 by the King Count�T Basin Reconnaissance Program)joins with tributary�0060, a Class III Stream. The stream ' continues north/northwest and e�-entually ioins the Black River. ��d � �'.�cr c:�:�.�r_c� '��-e.-. the Green River(see Drainage Map �o. �'; Core Desi;n. Inc PaQe o .��y-yy.� �� i�i/,�i�i�� /.� �. .... // i //� //i�i_�``\-�� _� //iir /` i�i `� I�J . r , i\i �, � � ._` , :i '� \ lfFe • / 1 / . _��:�-1' _'i i� =J'�i�%i __�' `1\_ �\ ' 1 i � { . .// f �' � � � 1. ... .- , , -� �—� '_ �` � ``.I \ �' 1 / d I 5 , � . / � '-- .Y�I � �// �\��, \\I 1 �. � ._.. � 1 � � i i � / ��/�� i�i f i� `� \ ♦�h '� �\� �, r � '1 1 4 �i . j �� j � ��\ •, i � � `� l � ! ( /�� 1 I i�" �--'_' _",,, .`,`4 , , J , ; ' ; ;' , +� �,..._; �. 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' - � • • � «, � + .. , � . �. . �� i f � ��. , :�- � - . _ ►, `, �. ��!AI� � � - �I _�Y�A� ��6�i � �i , .. �. � ,iiw�� -... � '� .. �� '� - � �� , � � ;;..�.-�� '- . ,' i ��.�:�� °;. � - �,. ��:q��l� I��' �� ' � •�� _ � � � l � � � � � , �I�� ,. �:� �� _ � M..�.�� I/.� _ ��' �'�� -�.�.��., ��.,� ,.� c� '�� - � � `=�r�,A,��r , �� '��.,�� - , �.<<� \ 'It \ ��I� 7' •` ��,_/ �"'�''�� ..�. �� lfi� �! � �� -��•"_ � �� .� �'� , , -,, -�.� _ �` �� ,. �, �'� �`�' � � �� , �� , ,, � � ��..� � �� _ � � _ � ��o ' �'- _ ' � �'' � ' ii � ; - � � _ �� ,��; �i''_�►'`�..� _ �� E� -- � ��'�� d ' ��`�� . ti.� ��.;�� .� � „ _� �11 l �, `r"..•�� ,: �� ,'-�.�� "�l�� _ �� r�.. . . .` w � '�'�� y �. 0 ,�� ..�� '�� _- ` _ . __ - �� .R ` �yww� - I �.►�� ,� ' R� �� , � �� - 1 � , �• �� : ,�! �e�� -�� i �m�-� �� . �� r� � �i'�� i��l�� '� , ��, - �: �► �� , r ..�� .�"�' _ - �' � % ��, ,�,� �- 'b�- � ' `�- ,� �: �� _►.�� , �� , �� '�,. ,. � /�, �►, � � ,: �, �r� t• ,�� - - •� .. ./.� '' -- = 'i�/,��/��L�. y � I __ '�. `� ��`� �� '� •��. �� '.� 4' . . ' .. �� ' � .� •• • r i • ,_�� r?ii .. . � ��, - �, 1 ,. ;. �- . � _.� . -- ---- .- t. .. .. �iING COUI`TTY, rVASHII� GTON, SL' RFACE .. ATER DESIGN r� ANUAL (2) CN values can be area weighted v✓hen they apply to pervious areas of similar CN's (within 20. CN poinis). However, high CN areas should not be combined with low• CN areas (unless the low CN areas are less than 15°/o cf the subbasin). In this case, separate hydrographs should be generated and summed to form one hydrograph. � ,'I ]FTGURE 3_S?A H,'DROLOGIC SOIL GROUP OF TIiE 50ILS II�' �ING COIJ�"f'Y ' HYDROLOGIC HYDROLOG}C SOIL GROUP GROUF* SOIL GROUP GROUF' ,� Ald2rwood C Or,;as Peat D Arents, Alderwood Frlaterial C Oridia D Arents, Everett Ffaterial B Ovall C Beausi'.e C Pilchuck C Befiingham D Puget D Briscat . D Fuyallup 6 ! Buckley D Ragnar B I Coastal Beaches Vzriabie Aenton D i Ezrimont Silt Lcam D Riverw�2sh Variabie Edgewick C Sala! C Evere.� A/6 �Sammamish D Indianola A' Seat[le D Kitsap C Shacar D Klaus ` C Si Silt C j Mixad Alluvia�Land Variable Snohomish D I , Neilton A 5ultan C Newberg 8 Tulnvila � I Nooksack C Urban Variable Norr,�al Sandy Loam D W'oodinville D HYDROLOGIC SOIL GROUP CLASSIFICATIONS � A_ (Lcw runoff potential). Soils having high infiltration rates, even when thoroughiy wetted, and ccr.sisting i chiefiy of deep, welf-to-�xcessively drained sands �r gravels. These soils have a high rte of water , transmission. � i B. (Moderately low runoff potentiai). Soiis having moderate infiltration rates vrhen Ihoroughly wettec, and consisiing chiefly of moderately fine to moderatefy coa;se textures. These soils have a majerate rate of wat�r transrnission. C. (Moderately high runoff poteniiai). Soils having slow infiitration rates when thoroughly wetted, and consisting chiefiy of soiis with a layer that impedes downward movemeni of water, or soils with mcderately fine to fine textures. These soils have a sJow rate of water transmission. D_ (High runoff po[ential}. Soils having very slow infiiiration rates when thoroughly wetted and consisting i chiefly of ciay soils with a high sweliing potential, soils with a permanent high water iable, so�s wiih a i hardpan or clay layer at or near the surface, and shallow soils over nearly impervious ma.erial. These soils I have a very slow rate of water transmission. ' ` From SCS, TR-55, Second Ed'Rion, June 1�, Exhi�r F,-;. Revisior.s rnace from S�, Soi: L�terpretaiion Reccrd, r=o;m �S, September i938. � � � �.�__ 11:9� KING COUNTY, W . ,iHINGTON, SURFACE WA � ER DESIGN MAIVUAL TABL£ 3.5?B SCS «'ESTE�2N WASHTNGTO?�' RUNOFF CUR�'E NLT?vfBERS � SCS WESTERN WASHINGTO�! RUNOFF CURVE NUNIBERS (Published by SCS in 1982) � Runorf curve numbers for selected agricultural, suburban and urban land use for Type tA rainfali disuibution, 24-hour siorm duration. ; CURVC NUMBERS BY I HYDROLOGIC SOIL GRQUP LAND USE DcSCRIFTION A B C D ; Cutiivated land(1}: winter condition I 86 91 9� 95 I hlount2in open areas: low growing brush and grass�ands 74 82 8S 92 I Meadow or pasture: I 6; 7g �g5 8g ' Wood or forest land: undisturbec or oider second growth '+2 64 � 87 , Wood or forest land: 55 72 �8�) 66 I young second growth or brush t ..,. Orchard: with cover crop 8� � � `��' I � Open spaces, lawns, parks, golf courses, cemeteries, landscaping. � good condition: grass cover on 75°,6 �, or more ot the ar2a 68 80 '��. 9G � fair cond'Rion: grass cover on 50�% � to 7�°h ot the area 77 85 90 92 ' Grave! roads and parking lots 76 85 89 9� iDirt roads and parking lots 72 82 8T 8B I impervious surfaces, pavement, roars, etc. 98 98 �98) 98 1 Open water bodies: lakes, wetlands, ponds, etc. 100 1Q0 100 100 I Single Famiiy Residential (2) I '� Dwelling Unii/Gross Acre % Impervious (3) � 1.0 DU/GA 15 Separate curve number 1.5 DU/GA 20 shali be selected 2.0 DU/GA 25 for pervious and I 2.5 DU%GA 30 impervious portion 3_0 DU/GA 34 of the site or basin 3.5 DU%GA 38 i 4_0 DU/GA 42 i 4_S DU/GA 40 5.0 DU/GF, a8 � 5_S DU�GA 50 � I 6.0 DU/GA �2 i 6.5 DU/GA 54. � 7.0 DU/GA . 50 ! Planned unit developrnents, °� impervious � condeminiums, apartments, must be computed i commercial business and i industrial areas. (1; For a more detaiied desc,iption or agriculturai land us� curve numbers refer to National Engineering Handbook, Section 4, Hydrology, Chapter 9, Augus; 79'2. (21 Assumes roof and driveway runoff is direcied into street/storm system. (�; The remainirg pervious areas (lawn) are considered to be in good condition for these curve numbers. �%-;, ll;o� T .,.�._-� �� ., _ �_.,�.� �"��iii`J� 27�;.9�.03Q�.. Densities and dimensions - residential zorses. rcESIDEidTlini. Z RURAL URBAN URBAN O N RE- RESIDENTIAL I E � S SERVE .`�r� ' I � STANUARDS RA-2.5 RA-5 RA-10 RA-20 � UR R-1 Rd R-6 R-8 R-12 R-'18 R-24 R-48 (17) �� Base Oensity: 02 � 02 0.'I OAS 02 1 4 6 8 �'12 18 24 48 ' Owe4ing du/ac dulac dulac dulac du/ac du/ac du/ac dulac du/ac �du/ac du/ac I du/ac du/ac � , UnitlAcre (21) (6) (15) Ma�dmum Dersity: Oft 0.4 6 9 '12 �8 I 27 36 72 Dwefling UniUAcra du/ac du/ac du/ac dulac � du/ac dWac dulac du/ac dWac ��) �20) �20) �2� MinimumOansity: 85% 8�� 85% 80! T5h 70% 65% �2) ('12) ('12) (92� {�8) ('18) (78) ('18) (�8) (t8) -('18) �Z3) Minimum Lct Area 1�75 3.75.ac 7.5 ac 15 ac (�3) ac ' � � Minimum Lot �35 it '135 ft '135 ft 135 k 35 ft 35�: 30 ft 30 ft 3D ft 30 ft � 30ft 30 ft 30 ft Width (� {7) I r3) • �- � Minimum SVeat 3U ft � 30 ft 30ft 30 ft I 30 ft 20 ft '10 ft 10 ft �0 ft 70 R 10 it 10ft '10 it Set6ack (9) (8) (9) (9) (7) (7) ($) (a) (e) f$) ($) [8l (6) (3) � Minimum Interiar 5 ii 10R 10 ft '10 ft 5 ft 5 ft 5 ft 5 ft 5 ft � 5 f[ 5 ft ' S ft 5 ft i Setback �9) �9) (9) I �9) ��) �7) ('f0) (70) ('ID) (�p� � (3)('16) Base HeigM 40 fr d0 ft 40 ft ' 40 ft 35 ft 35 ft 35 K 35 ft 35 ft 60 ft 60 ft 60 ft fi0 h '� (4) 45 ft 45 ft BO ft 80 ti 80 it i (14) (14) (�4) ��4) ��41 Maximum 25Y. 20% �5% 12.5°6 30% 30% 55% 70% 75i6 85% 85Y. 8596 90% � Impervious . " (��) (��) �ii� (1�� i� �. Surfacec (�9) ('19) (�9) (79) � � Percertage(5) . . . B. Development conditions. 1. This maximum density may be achieved only through the application of residential density incentives in accordance with K.C.C. chapter 21A_34 or transfers of density credits in accordance with K.C.C. chaPter 21A.36 or 21A.55, or any ccmbination of density incentive or density transfer. Maximum density may oniy be ex�eeded in accordance with K.C.C. 21A.34.040F.1.g. 2. Also see K.C.C. 2�A.12.060. 3. These standards may be modified under the provisions for zero-lot-line and townhouse developments. (King County 3-2001) 2�A—'05 SITE STATISTICS Total Area 2�9;2�G (5.952-ac) �o. ot Lots 36 tiNDE�'ELOPED �'�"etland Tract 10,456 - Subtotal 10,456 (0.240-ac) Total De�-eloped 248,794 (�.712-ac) I'11PER'4'TOUS I'�1ain Road��ays: Onsite Major 32,617 Onsite Minor 12,099 �a,�16 Lot� (R-8: ?5% Impervious) 140,799 140,799 Subtotal 185,�1� PERti�OtiS L.ots (1�,,731sf-140;799s�: 46,932 46,93? ��Tetpond Tract 16,�47 16,347 Subtotal 63,279 Total 248,794 i ; . � 'l ' . . 1 Core Design,Inc. Stonehaven Po � �f� � � �, Lot Breakdo«Tn ' Area � � ; :�rea (s� � : ! Area (s� i ; � Area (s� � Lot No. (SF) � Lot '_vo. (SF) � Lot No.j (SF) � �Lot No. (SF) 1 �,259; � 11 j 4,500� � 21 � 4,9?�' 31 4,801 2 ' S,402 ; 12 I 4,�OG 22 4;�02 32 ; 5,363 3 �,402 13 ' 4,516, 23 � 4,502� 33 7,266 4 5,104 14 4,762 24 11,�83, 34 4,502 5 6,390 15 �,161 25 4,639 3� 4,�02 6 4,70U 16 6,396 26 4,�02 36 5,278 7 5,730 17 5,2?0 27 , �,278 � 8 � 5,790 18 4,662 28 5,259; 9 4,501 19 4,664 29 4,502I 10 4,500, 20 4,506� � 30 4,�02� � I � � I ' I I ; �TOT.a_L� 187,731 � _ Ca�e Design,Inc Stonelia��en Pe'-o�� 1/19/04 1:15:42 pm Core Design, Inccrpo_ated page 1 STONEHFti"EN JAI�TUARY 2 0 0 4 CCRE JOB NG. 03095 BAS IN SUMbiARY BP_SIN ID: 2-YR-EX NP.ME: 2-YR EXISTING SBUrI METHODOL0�3Y TO'_'AL AREA. . . . . . . : 5.7� Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : ''_'YPElA P�RV IMP PRECIPITATION. . . . . 2 .00 inches I�RE�_. . : 5.39 Acres 0.32 �cres TIME INTERVFL. . . . : �O.DO mir: CN. . . . : 81.00 98 . 00 � TC. . . . : 45.00 min 4� . 00 m=n P�STR.r'?CTION CO^FF: C .�Q PE.=_rC _�-i�� . 0 ._ . �t� -:_�. _ ._? =�--t T?:�:E: �:�� ..,--- B.�_'rv' i�-`_'�-�:: :�__'�_�: iC-'_'F E:-ST=I7G s�u: r1�,r�c�oLo�� TOTF� P.REP_. . . . . . . : 5 .T Acres BASErLOWS : � . ::G ==s P.A=NFALL TYFE. . . . : TYPElA PEP.V I.�IF P�ECIPITATION. . _ . : 2 .90 inches ��P_. . : 5.3S Acres 0 .32 Acr�s TiME II�'ERVT�L. . . . . 10.00 mir. CIu. . . . . b1.00 S� ��0 TC. . . . : 45 .00 mir_ _= _ _ .• _-- P�STRACT�027 COEFF: 0 .20 ----- �_=_^'E . _ . �_ _-_. -:_�. _ __ �_._--� ^I'_- . _=. -.-.- _ - - y- -_ _ _ _=_.'r� "__ _ _ : -:. ji�i�t I'+1E'TEvDG:�::='_ -- - -- - TOTAL AFcEA. . . . . . . : 5 .71 Acres BAS�FLO[tiS : � . _ � RAINFALL TYPE. . . _ : '_T'YPElA Pr.RV PRECIPITATION. . . . : 3 .9C _nches AREF. . : 5.35 Acres C . TIME INTERVAi,. . . . . 10 . �� m-r CI<. . . . . 51 . C� °S - - ABSTRACTION COEFF: 0 .2C PEAK RATE: 1.63 cfs VO�: _ . . � ___ -� __:.._ . �' �; �...._ Y' � 1/19/04 1:15:42 pm Core Design, Incorporated page 2 S TONE��TE2v JPNUAFcY 2 0 D 4 CGF,E JOB N0. 03095 BAS IN SIII�iP_RY BASIN ID: 2-YR-DEV NAME: 2-YR DEVELOPED SBUH METHODOLOGY TOTAZ F,RE�. . . _ _ . . : 5 . 71 Acres BASEFLOWS : 0.00 cfs RRINFALL TYPE. . . . : TYPElA PERV INP PRECIPITATION. . . . : 2 .00 inches FREA. . : 1.45 Acres 4 .26 Acres TIME INTERVPL. . . . : 10 . 00 min CN. . . . : 66.OG 98 .00 TC. . . . : 10 .00 min 10 _00 min ABSTRACTION COEFF: 0 .20 PEAK RP_TE: 1. 89 c�s VOL: 0. 73 Ac-ft TIME: 480 min BASIN ID: 10-YR-DE NAME: 10-YR DEVELOPED SBLT� METHGDOLCC�' TOTP.L ARER. . . . . . . : 5. 71 Acres BASEFLCWS : 0.00 cfs RAINFfiLL TYPE. . . . : TYPElF PER�r IMP PRECIPITP_TION. . _ . : 2 . 9G inches A1?E�. . : �.�5 Acres 4 .26 Acres TIM� IIvTERVAL. _ . . : 10. 00 min CN. . . . : 86. 00 98 _GO TC. . . . : 10. 00 min 1G . 0a min ABSTFcACTION COE�F: 0 .2 0 P�.�IC FcA'TE: 2 .94 cfs VOL: 1.14 Ac-f� TIME: :80 min BASIN ID: 100-�'R-D NAME: 100-YR DEVELOPED SBUH METHODOLOGY TOTAL AR�A. _ . . . . . : 5 .71 Acres BASBrL047S : 0_CO cfs FcAIN=ALL TYPE. . . . : TYPELA PrRV I:✓�P PRECIPITATION. . . _ : 3 .90 inches P.REA. . : 1.45 Acres 4 _26 .Acres TIME INTERVAI�. . . . : 10. 00 min CN. . . . : 86. 00 98 .00 ';'C. . . . : 10. 00 min 10. 00 min ABSTRACTION COr,FF: 0.20 PEAK RATE: 4 . 13 cfs VOL: 1 . 6G Ac-�t TI'�I�: 49C mir_ l � •r= � 1/1S/04 1:15 :42 pm Core Design, Incorporaced page 3 S TOrdEH.�JEN JAI�]UARY 2 0 0 4 COitE JGB N0. 03055 BAS IN SUMI✓LARY BASIN ID: 2-YR-IIPS N_�ME: 2-YR UPSTREF,M SBUH METHODGLOGY TOTF1, A.REA. . . . . . . : G.45 Acres BrSEFLOWS: O . 00 cfs RT�INFALL TYP�. . . . . 'I'1'P�1� PERV IMP PRECIPITATION_ . . _ : 2.00 inches F�nA. . : 0.4� �cres G. 00 Rcres TIM� INTERVAL. . . . : 10. G0 min CN. . . . : 81_ 00 0. 00 TC_ . . . : 4b . 00 min C . 00 min ABSTtZP_CTION CO�FF: 0.20 P�P�C R�TE: 0.02 cfs VOL: 0.02 P_c-ft TIMB: 5�0 min BASIN ID: 10-YR-IIP ISAME: 10-YR IIPSTREAM SBU_T-i ME'3'HODOLOGY TOTFZ AREA. . . . . . . : 0.45 Fcres B?�SEFLOWS: 0 . 00 c=s RAINFALL TYPE. . . . : TYPElF PERV _TMP FRECIPITATI�N. . . . . 2.50 inches AREF. . : 0.?5 Acres 0. 00 P_cres TIME �NTERVAL. . . . : lO.00 min CN_ . . . : B1. 00 O . GO TC. . . . : 45. 00 min C . 00 min ABSTRACT'ION COEFF: 0.20 PE.�K RATB: 0 .07 cfs VOL: 0. 05 Ac-ft TIME: 490 min BASIN ID: 100-YR-II NAMFs: 100-YR UPSTREAM SBL�3 METHODOLOGY TOTP.L AREA. . . . . . . : 0 .45 Acres BASEFLOYuS: 0 .00 cfs RAINFALL TYPE. . . . : TYPElA PEnV IMP PRECIPITATION. . . . : 3 .90 inches AREA. . : 0.45 Acres 0 . 00 Acres �I � TINIE INTERVPL. . _ . : 10.00 min CN. . . . : 61.00 0 . 00 TC. . . . : 45. 00 rnin 0 . 00 mir. ABS'."RACTiON COEFF: 0.2 0 PEAK RATE: 0 .12 cfs VOL: 0 .08 Ac-ft TIME: 490 min BASIN ID: 2-YR-WQ NP�IE: 2-YR WATER QUALITY SBUH METHODOLOGY TOTFL: AREA. _ . . . . . : 5.71 Acres BASEFLOWS: C . 00 cfs R�INFALL TYPE. . _ . : TYPEIF PERV IMP PRECIPITATION_ . . . : 0.67 inches AREA. . : 1.45 Acres 4 .26 Ac_es TIME INTERVAL_ . . . : 10.00 min CN. . . . : 86. 00 98 _ 00 TC. . . . : 10.00 mir� 10 . 00 min ABSTRACTION COEFF: 0.20 PEFF� i�ATE: 0 .45 c�s VOL: 0 . 18 Ac-ft TIME: ��0 mir_ { 1/19/04 1:15:42 pm Core Design, Ir_corporated p�ge � STONEHFVEN - J'-�NUF FcY 2 0 Q� CORE JOB N0. 03G95 HYDROGRAPH SIINII�SARY PEF�C TINE VOLUMB HYD RiRJGFF OF OF Contrib NL7M R�^E PE_AK. I3YDR0 Area cfs min. cf\AcFt Acres _______=====7________________________________ 1 0..,74 490 13907 cf 5 . 71 2-yr Existir_g 2 0.918 490 27329 cf 5 . 71 10-yr �x�sting 3 1.631 490 44159 ci 5 .71 100-yr Existina ' 4 C .02� 540 981 cf 0 .�5 2-yr Ups�ream 5 0 .065 a90 2007 cf 0 .45 10-y� Jpstream 6 0 .121 4S0 3306 cf 0 .45 100-yr Upstream 7 1_894 a80 31910 cf 5 . 71 2-yr Developed 8 2 .Sa3 480 49577 cf 5 .71 �0-yr Developed 9 4.120 480 69620 cf 5 . 71 100-yr Develeped 10 0_398 450 14888 cf 6. 16 2-yr Fxisting & 2-yr Up 11 0.98� 490 29337 cf 6. 16 10-yr Exist=r.g& iG-yr Jp 12 �.751 490 47465 cf 6.16 100-yr Exist.�ng&100-yr Up 13 1.915 480 32891 cf 6.16 2-yr Developed s 2-yr Up 14 3.003 480 51584 cf E. 16 10-yr Develope3& 10-yr Up 15 4.240 a80 72927 cf 6 . i6 100-yr Developed&100-yr Up 16 0.402 800 32891 cf 6 . io 2-yr Deveicped Outflow 17 0.984 570 5i584 cf 6_16 10-yr Developed Outflow 16 1.754 550 72927 cf 6 .16 1D0-yr Developed Outflow 1/19/04 1:15 :�2 pm Core Design, Incorporated page 5 STONEHAV�N JPNUARY 200� CvRE JOB NO. 03055 STAGE STORAGE TABLE :, TRA_pEZOIDAL BAS�N I� No. P-POND Description: PRELIMINF�I'cY POND Length: 70 .00 ft. 4Tidth: 28 .50 ft. Side Slope 1 : 3 Side Slope 3 : 3 Side Slope 2 : 3 Side Slope 4 : 3 Infiltration Rate: O.CO rnir/inch STAGE <-STOR�GE--> STFGE c-STORAGE--> STEGE <-STOP�GE--> STFG� <-STORuGE-> (ft) ---cf--- (ft) ---cf-- (ft) ---cf--- (ft) ---cf--- 381_ 00 0 .0000 383. 10 5604 385.20 14461 387.30 27297 381. 10 202 .§7 3&3 .20 5947 385.30 i4996 387.40 28017 381.20 410 . 92 383.30 6298 385.�D 15521 387.5G 2B748 381. 30 E�5 .42 383 .40 6056 385.50 16055 387.60 29489 381.40 845. 05 383 .50 7022 385. 60 165:8 387.70 30241 381.50 1073 383 .6G 7�95 385. 7C 17150 387.80 31003 3.81. 6C 1306 3b3 .70 7777 385. 80 1771i 387. 90 31776 38i. 70 1545 383 .80 8166 385.90 i8282 388 . 00 32561 381. 80 1791 383 .90 8563 386. 00 15863 388 .10 33356 381.90 2044 38a .00 6909 386.10 15452 388 .L0 34i6� 382. 00 2303 384 .10 9382 386.20 20052 368 .30 34979 3fi2 . 10 2568 384 .2C 9803 386.30 20661 388 .40 3580? 382.20 2840 384 .30 10233 386.40 2�279 386.50 36647 382 .30 3119 384 .40 10671" 386.50 21908 388 .60 37498 382 .40 3405 384 .50 11117 386. 60 22546 368 .70 38360 382 .50 3698 384 .60 11572 386. 70 23195 388 . 80 3923a 382 . 60 3998 384 .70 12035 386. 80 23853 388.90 a0119 382. 70 �304 384 .80 �2506 3fi6. 90 24521 3�9. G� 410iE 382. 80 461� 384 .90 12987 387. 00 25200 382 _ 90 49�C 385 .00 13476 387 . 10 25889 3b3 . �0 5268 36� . 10 13°7= �8'' .2C 25�89 1/19/04 1 :15 :42 pm Ccre Design, Incorporated page E STONEH�VEN JPN'JARY 2004 CORE JOB N0. 03095 STP_GE DISCHARGE TABLE MULTIPLE GRIFIC� I� No. P-ORIF i Description: PRELIMINF�Y ORIFICE Outlet Elev: 381.00 E�ev: 3'79.00 ft Orifice Diar:eter: 2 . 8500 in. �lev: 385 .50 ft Orifice 2 DiameLer: 4 . 5336 in. �lev: 385 .30 ft Orifice 3 Diameter: � .�53= ir:. S^AGE <DISCIizFcGE> STFGB <-D=SCHARGE-> STAGE <-DISC_�iF'�12GE-> S'I'AGr. <-DISCH.�GE-> (ft) ---cfs-- (f�) ---c_s-- (ft) ---cfs- (ft) ---cfs-- ---------------------------------------------- 381. Oa 0 .0000 382 .30 0.2513 383 .60 G .3554 38�. 90 0 . 8530 381. 10 0.0697 352 .40 0.2506 383 .70 0 .3622 385. OQ 0 . 9079 381.20 0 .0986 382 .50 0.2700 383 . 80 0 .3688 385. 10 0 .5580 38�.30 0.1207 382 .60 0.2788 363 .90 0_3?5� 385 .20 1. 604� 381.?0 0.�39? 382 _70 0.2874 384.00 0 .381B 385 .30 1 . 0479 ' 381. 50 0_1559 382 .80 0.2S57 384.i0 0.3881 385 .40 1 .2�92 � 381. 60 0.1707 382 .90 0.3036 384 _2C 0.3943 385 .50 1 .3686 381. 70 0.18�4 383 . 00 0.3117 364 .30 0.4004 385. 60 1 .4603 381. 80 0 .1971 383 .10 0.3194 3B4.40 0.4�6� 385.?0 _ .5�18 381. 90 0 .2091 383 .20 0.3269 38�.50 0.412� 385. BC 1. 616� 382 . 00 0_2204 383 .30 0.3343 384 .60 0 .6271 385.90 1 . 6863 382 . 10 0.2312 383 .40 0.3a15 384.70 0.7194 386. 00 1.7521 ' ; 382 . 20 0.2415 383 .50 0.3485 384 .80 0.7915 I � �::� �: J. _ . r _� 1/19/04 1 :15_42 pm Core Design, Ir_ccrporated page 7 STONEHP_VE11 JA DTi.TARY 2 0 0 4 CORE JOB N0. G3095 -------------------------------------- � LEVEL POOL TF.BLE StTMMARY I qrt; MF;TCH IIdFLOW -STO- -DIS- <-FE_�K-> OUTFLOin' S'^ORA�= <-----DESCRIPTIOiJ-------> {cfsi cfs) --id- --id- <-STP_GE> id (cfs) VOL (c=i 2-YR EXISTING . . . . . . . . . . 0.40 1.91 P-POND P-ORIF 384 .33 16 0 .4G =0354. 1E c= _G-YR EXISTING . . . . . _ . . . . 0.98 3 .00 P-PODTD P-ORIF .s65_16 17 0 . 5E 14258.45 �- =GC-YR EX_T�TI=dG . . . _ . . . . . . 1. . � � .24 F-PCi�T, P-Ok=� ?86. ..� �_ 1 . ?5 18cE2 . 54 c- �fr` . ' POND VOLUI�TE C:�LCULATIONS CORE # 03095 Stoneha�c�en Z'4'ater Qualit��/Detention Pond COMBINED INCRE'VIENTAL TOTAL. ELEVATION CELL 1 CE.LL ? CELLS �'OLL�2E VOLITl��2 SF SF SF CF CF Se;�ii_�Cnt Stora�e 377.00 360 NiA 3 78.00 62-0-: ' N/A 377.00 0 630 630 1'�-erpool 378.00 620 864 1,494 747 �Dead Storage) 380.00 1,2�2 1,39� 2,647 4,141 ��,-Q V�Tater Stufac 381.00 1,733 l;?82 3,51� 3,081 7,969 ?3c�i� Detention 381.00 3,�1� 382_00 4,383 3,949 3;949 384.00 6,516 10,899 14,848 ' 386.00 8,877 15,393 30,241 TOTAL PO'_�lD VOLL�iE �8,210 �� ; � . � � . ,.. . i - I � �. � � � ;y s F . -_ �:� �� -_- - � _ Eh rSTING : ,. ��g � - 1".,^_.. �;_-�. '�--'.'"""...._.. — ' ' :=-c' ,�S'^-� _ .�....�-.�.�' 'rtF �.. I � _ � � -___ r"_' ...-,., , F' � i , ,_ = CULVERT �N I � _ F:. .. ` _ � .= u f Y f- .c _ � 2- � _ ..-,- _ _ � r_ � _ __ ' t �_ ;:.-� ..t ..� _ � r. ; � :::-_8'.^4.,x_.^...� . .. --� .h.••' ,. �1. _ F"' y''r,_ � '\ .,.....__..`....}��.-. _ _ � � �- ..-... �- . . -'. '.; _ ' _.' '__- ' ' ' - -- - " ..�,, -_. �. -� '-�. :. -„._ - � ._.. _ �..,m.�d.._-_ _' :',,r.�c,„��.� - e � '. 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';j=;y � 'M �� ' . c�� ` I � I '�-�''' --- � _ _ I � IIr � 1,` - \ " '�I . ;� ��; �� / ' � I� � !h 'l; a r _ � a � �" � \\ .,\\ \ ' �1 I '�� C {q I7'.I . ��y � I i '_� '�:;: �----------- n'� � . 5.7.; r � •rs--- i n'I 1 394------�i �_ ' �� ;�i � � --'b 6==�=- w NI j O � 2 � SWALE DIMENSIONS: o � � 2.•1 SQE SL OPES � � 0=1.29' H=2.29' � W=11.16' (USE 11.25) a 3:1 SlDE SLOPES Z ? J H=2.16' W � � m W=14.96� (USE 15) � Q � NO TE.• DITCH TO BE EXCA VA TED � � � ENOUGH TO NA I/E DIMENSIONS AB01/E o AFTER ROCK IS INSTALLED. � � ry � � Q W . �, ��\��% �� %�\��`� � � //� \ ��\/ � ;�/��, . . ��\�� + H �/\\�/\�/ p //\��`�/ Q \�\�'\ _ ` ��/• ��j\\��_\\,.\\, \;��,/.� DESIGN WA TER SURFACE ELEV. ,�///\j/�//� /i FILTER FABRIC LINER 2, l" ROCK TNICKNESS UNDER ROCK a a 3 3 � h NOT : o o m ROCK LINING SNALL 8E REASONABLY > > Z WELL GRADED AS FOLLOWS: � z� Q ¢ � MAXIMUM STONE SIZE: 12 /NCHES �� o MEDIAN STONE SIZE: 8 INCHES MINIMUM STONE SIZE: 2 /NCNES a 3 b DESlGN NOTES: ;N � o_ RlP RAP ARMORING DESIGN BASED ON 7998 �w `z � KCSWDM TABLE 4.4.1.A FOR FLOW OF 32.62 CFS �o � � �. AND �ELOCl71ES OF 5.49 FPS (2:1 SIDE SLOPES) °'� '' � m AND 5.10 FPS (3:1 SIDE SLOPES). o � � � E � z � W ti ' �' v�i a o 0 0 c� w� R/P RAP ARM�R/NG �;o W W �� NOT TO SCALE g� ]Z � ;�� .a �� p � d� ;a �mJ o p°:� o . � <W � �