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Home My WebLink About03385 - Technical Information Report � � � � Site Development Associates, LLC �1 rn m a i ' " II c � • I • - • � . � . Project Location: 12G2G 142�'� �,verue SE Renton, WH ��059 Prepared For: I Offe Engineers I 13932 SE 159tr' Place I Renton, WA 98058- � '�32 �� Prepared By: Si?e Develapment Associates. LLC ^u 117 Main Street BOt"�il �l'�l?, 93�11 Date: A�,gust 1 G, 2Q0� Project Number: : ('-° r� r�•^� 1�r-�.; �o-vu � � 3 38� ..ae� ��1�. Site Development Associates, LLC , � . . : . • e - e -s - Project Location: 12226 142`"' Avenue SE Renton, WA 9805� Prepared For: Offe Engineers 13932 SE 159 Piace Renton, WA 98058- 7832 Prepared By: Site De�elopment Associates, LLC 10117 Main Street Botheil, 1r1�A 9�011 �S. A. �G�� Si� Date: :�'� y: August 10, 2007 . • . � . : • Project Number: : 3 '�v 107-016-008 .c/ RF;�'\��c' S SS�oNa��-`'G ; ��, p� � IXPIRES 6/9/2009 . � : - � Y .._ __ . . ._.____. Site Development Associates, LLC TABLE OF CONTENTS SECTION 1 - PROJECT OVERVIEW SECTION 2 - CONDITIONS 8� REQUIREMENTS SUMMARY i Task 1 —Summary of Core Requirements Task 2—Summary of Special Requirements Task 3—Summary of Additional Requirements SECTION 3 - OFFSiTE ANALYSIS Task 1 —Study Area Definition & Maps Task 2—Resource Review Task 3—Field Inspection Task 4—Drainage Description & Problem Description Task 5—Mitigation of Existing or Potential Problems Appendix 3-A — Resource Review Documents SECTION 4 - FLOW CONTROL 8�WATER QUALITY FACILITY ANALYSIS 8� DESIGN Part A—F�cisting Site Hydrology Part B—Developed Site Hydrology Part C—Performance Standards Part D—Flow Control System Part E—Water Quality System Appendix 4-A—Suppo�ting Documents for Hydrologic Model SECTION 5 - CONVEYANCE SYSTEM ANALYSIS 8� DESIGN SECTION 6 - SPECIAL REPORTS & STUDIES SECTION 7 - OTHER PERMITS SECTION 8 - CSWPPP ANALYSIS 8� DESIGN SECTION 9 - BOND QUANTITIES, FACILITY SUMMARIES, AND COVENANTS SECTION 10 -OPERATIONS 8� MAINTENANCE MANUAL - � �` ��_ E� � � _____ _ . Site Development Associates, LLC SECTION 1 PROJECT OVERVIEW LANGLEY MEADOWS SECTION 1 107-016-006 PROJECT OVERVIEW � � ` �" Site Development Associates, LLC PROJECT OVERVIEW Langley Meadows proposes the subdivision of five existing tax parcels into 70 single-family residential lots, along with the associated roads, sidewalks, and utilities. The project will also include provisions for the adjacent short plat (Blessing). A project summary (TIR) worksheet has been included in Figure 1 of this report. The project is located near the center of Section 10, Township 23 North, Range 5 East, Willamette Meridian. More specifically, the project is located at 12226 142"d Avenue SE, in the City of Renton. A map of the vicinity has been included in Figure 2 of this report. The project site currently contains a handful of small homes, detached garages, etc. These existing buildings will be removed as part of the proposed development activity. The remainder of the site consists of small driveways, landscape, and lawn area. The general topography of the site can generally be described as gently sloping to the east, to a large off-site wetland area. No wetlands or other critical areas existing within the site boundary. The proposed development will include the installation of roads, sidewalks, and utilities, including a stormwater detention and treatment facility. The facility will be designed in accordance with the 2005 edition of the King County Surface Water Design Manual (KCSWDM). The proposed facility is an underground vault, which provides live storage for detention, as well as permanent wetpool storage for stormwater treatment. Detained and treated flow will be released to the off-site wetland area. Figure 3 shows the site characteristics and proposed drainage patterns. The site is underlain by Alderwood soils, according to the USDA soil survey of King County. A portion of the Soil Survey map is shown in Figure 4 of this report. LANGLEY MEADOWS SECTION 1 107-016-006 PROJECT OVERVIEW K1NG COUNTY, ��ASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 : PRO.lECT OWNER AND. '. Pa�t 2 FRO;fECT�iDCATION AND ��. � ` PROJECT`ENGINEER . � � •.� ` DESCRIPTION' , .. ., _ , �, ., Project Owner Project Name LA,��y��lvor..�s Phone DDES Permit# Address Location Township �3 � Range $�� Project Engineer /�r'�v /7GINTy�7�¢ Section �� Company �;i ��v��cw.srE•vr �ss�..srss SiteAddress /tZZ6 /y2=�� X= Phone Zs R�S3 �� £ �� Part 3 r�P � �- �APPLtCl�7 X� ';��. �� : �S� r _n --��.�. ;��`� �• t# �� ?'��.� �":' �� .� � Landuse Services ❑ DFW HPA ❑ Shoreline Sub iviso / Short Subd. / UPD ❑ COE 404 Management ❑ Building Services ❑ DOE Dam Safety � Structural �F/Commerical / SFR RockeryNaulU Clearing and Grading ❑ FEMA Floodplain ❑ ESA Section 7 ❑ Right-of-Way Use ❑ COE Wetlands ❑ Other ❑ Other ' i � _ � Part 5 -�PLAN;_ ` ; : _ _ - . _ ,. ,_ _ .: _ � _. ._. _ .:.� 1. .:� �.. _. _ �� . Technical Information Report Site Improvement Plan Engr. Plans) Type of Drainage Review�I Targeted / Type(circle one): ��-I-u I�f Modified I (circle): Large Site Small Site Date (include revision �r CouE�Z Date (include revision �` �rA,t/S dates): dates): Date of Final: Date of Final: ��`�' '�`-��_ `_=;� � , - ,�� 7'.�APSPa�� ; f _ ..�.. - - - _�. - Type (circle one): Standard / Complex / Preapplication / Experimental/ Blanket Description: �nclude conditions in TIR Section 2) /y Date of A roval: FIGURE 1 2005 Surface Water Design Manual 1/1J0� 1 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MA1�`UAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET -Part 7 -:P�IONITORING RE.QUIREMENTS ` - = - .. . . _< � . �:�, ._. :, Monitoring Required: Yes r��"} Describe; y� Start Date: �� Completion Date: �� Part 8 ..S1TE.GOMMUNITY AND DRAINAGE BASIN � - -- - Community Plan : Crr c�i= %�'�c.r�,�J Special District Overlays: Drainage Basin: (_o�E.� ��,d-�vt� Stormwater Requirements: /��i� Part 9 :ONSITE AND ADJACENT SENSITlVE AREAS - ❑ River/Stream ❑ Steep Slope ❑ Lake ❑ Erosion Hazard �Wetlands �`��.lLr=NJ� ❑ Landslide Hazard ❑ Closed Depression ❑ Coal Mine Hazard ❑ Floodplain ❑ Seismic Hazard ❑ Other ❑ Habitat Protection ❑ Part.1� .SOILS ``�' - Y � #.' -- = - - Y. 3 Soil Type Slopes Erosion Potential , ��/3 O- r�� -,�rc�,a,�.-z .�� G a--/S� � -.��,�,✓r ❑ High Groundwater Table(within 5 feet) ❑ Sole Source Aquifer ❑ Other ❑ Seeps/Springs ❑ Additional Sheets Attached FIGURE 1 {CONTINUED} 2005 Surface�'Jater Design Manual 1/1/OS 2 KING COli;�T�', WASHINGTON, SURFACE ��'ATER DESIGN MANliAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET � ; �,: �, ��r�'[1 A�`t�fi D.ESIGia1�M1TA71+Q�S�� _ - 1 ' � ,�. v � .¢�-��,.� - REFERENCE LIMITATION /SITE CONSTRAINT �Core 2—Offsite Analvsis ❑ Sensitive/Critical Areas ❑ SEPA ❑ Other ❑ ❑ Additional Sheets Attached Parf 12 TIR SUIUIMARY SHEET rovide one TIR Summar Sheet er Threshold Dischar e Area Threshold Discharge Area: name or descri tion Core Requirements (all 8 apply) Dischar e at Natural Location Number of atural Dischar e Locations: / Offsite Analysis Level: I 2 / 3 dated: �c=< ��2 Flow Control Level: 1 / 3 or Exemption Number incl. facili summa sheet Small Site B s Conveyance System Spill containment located at: U/Sr/�� ca�= �x�f.�i��w Erosion and Sediment Control ESC Site Supervisor. ro � �F:�•es'��.�ff7 Contact Phone: ,F� P�=�'�'^�%�'�'%�`' �`'��"'"`'Y� After Hours Phone: Maintenance and Operation Responsibility: Private / ublic If Private, Maintenance Lo Re uired: Yes /No Financial Guarantees and Provided: Yes / No Liabilit Water Quality Type: ' / Sens. Lake / Enhanced Basicm 1 Bog I (include facility summary sheet) or Exemption No. Landsca e Mana ement Plan: Yes / No S ecial Re uirements as a licable Area Specific Drainage Type: CDA 1 SDO! P /BP /LMP/Shared Fac. !None Re uirements Name: FloodplainlFloodway Delineation Type: Major / Minor / Exemption / on 100-year Base Flood Elevation (or range): Datum: i Flood Protectivn Facilities Describe: �/� Source Control Describe landuse: � � (comm./industrial landuse) Describe any structural controls: ' 2005 Surface Water Design Manual FI GURE 1 3 {CONTINUED} KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TiR) WORKSHEET Oil Control High-use Site: Yes / o Treatment BMP: itl�i� Maintenance Agreement: Yes � '�'' with whom? Other Draina e Structures Describe: Part 13 -EROSIQN AND SEDIMENT CONTROL REQUIREMENTS MINIMUM ESC REQUIREMENTS MINIti1UM ESC REQUIREMENTS DURING CONSTRUCTION AFTER CONSTRUCTION Clearing Limits �Stabilize Exposed Surfaces Cover Measures Remove and Restore Temporary ESC Facilities Perimeter Protection Clean and Remove All Silt and Debris Ensure Traffic Area Stabilization k Operation of Permanent Facilities Sediment Retention �-J Flag Limits of SAO and open space preservation areas ,�,(Surface Water Control ❑ Other IL�F Dust Control �:- n�c<<�Ss��Y� Construction Se uence P.art 14;:STQRMWATER�.F�AGILITY QESCR1PT10NS'Note::lnclude Facili �`Summa ".at��_ � Flow Control T e/Descri tion Water Qualit T e/Descri tion � Detention �Av�� ❑ Biofiltration ❑ Infiltration �Wetpool �� '�%�� ❑ Regional Facility ❑ Media Filtration � Shared Facility ❑ Oil Control ❑ Small Site BMPs �Spill Control �G,�,�_ ! ❑ Other ❑ Small Site BMPs ❑ Other , FIGURE 1 {C�NTINUED) 2005 Surface Water Design Manual 1;'1!OS 4 KING COUNTY, WASHINGTON, SURFACE V4'ATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 15 EA5EMENTS/TRACTS Part 16 STRUCTURAL°ANALYSIS Drainage Easement Cast in Place Vault Access Easement ❑ Retaining Wall ❑ Native Growth Protection Covenant ❑ Rockery> 4' High ❑ Tract ❑ Structural on Steep Slope I ❑ Other ❑ Other Part 17 SIGNATURE OF PROFESSIONAL ENGINEER I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attached Technical Information Report. To the best of my knowledge the in�mation provi d ere is accurate. �� 3� �� Si ned/Date FIGURE 1 (CONTINUED} 2005 Surface Water Design Manual l:'1/05 5 W Q �� C] Z M � � 3 � W 9 � � � 1- Q � = L Z Q'� 9<<F w � Z D ¢ 1'�l �'� B�v n o > c�, , j ¢ N S� K";r, PP� J �� _ a �� > � NE 12TH ST n� 9� z =w G�'S' w �-N o�W �r .-�> ¢ E IOTH S Pro � ect SE 116 T ST Location W NE '1 N ST Z /,, z W w O N � A H � � J a -1 W S 2 W - � Z > O a Z G r� x � m y M � NE 4TH ST SE 128TH ST w � w w ��; z w > a� v� a � w o ¢ � _ cn ¢ t- �D T °° N� � � a �� 0 � � � N � � � �esi9n LANGLEY MEADOWS `�' �pZ � � � N T S �' 5/12/08 Site Development Associates,LLC Scale � D 8t6 ��Bothell Way NE;Bo1heX,WaSMngton 98011 _.._.. ..___.. _._... .___... � ��7-�16�06 Office:425.IB6.6533 Fmc:425.186.6593 wwH.sdaengineers.com VICINITY MAP 2 � Project No. Figure No. 0 z wm m �. � � Z zu� �� `--�_ - .� � .�- � �-�J - ,, � �, _;� � Z ,�' ' ' �l-_�-_, �� O � � �� J � Q � � c JERICO AVENUE NE Q a' 1 1 1 ---�_ a W � � 1 �' � O O �i O � t3' � � � I €2J � 1� � � � '� � 1 � ��. 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Klaber-Cinebar silt foams, 0 to 8 percent In the areas used as pasture or cropland, the main slopes, is an exampie. limitations are the slope and the muddiness caused by This survey includes misce!laneous areas. Such areas seasonal wetness. Proper stocking rates, pasture rotation, have little or no soil material and support little or no and restricted grazing during short wet periods help to keep vegetation. Rock outcrop is an example. the pasture in good condition and help to control runoff and Table 4 gives the acreage and proportionate extent of erosion. Grazing when the soil is wet results in compaction each map unit. Other tables (see "Summary of Tables") of the surFace layer and poor tilth. give properties of the soils and the limitations, capabilities, Douglas fir is the main woodland species. Among the and potentials for many uses. The "Glossary" defines many trees of limited extent are red alder, western redcedar, of the terms used in describing the soils or miscellaneous western hemlock, and Pacific madrone.The common forest areas. understory plants are salal, Oregongrape, western brackenfern, western swordfern, and evergreen huckleberry. Map Unit Descriptions On the basis of a 100-year site cur�e, the mean site index for pouglas fir is 146. On the basis of a 50-year site 1-Alderwood gravelly loam, 6 to 15 percent slopes. This curve, it is 111. The highest a�erage growth rate in moderately well drained soil is in glacially modified areas unmanaged, even-aged stands of Douglas fir is 153 cubic on foothills and in valleys. It is moderately deep to ortstein. feet per acre per year, occurring at age 60. It formed in dense glacial till. The native vegetation is The main limitation affecting timber harvesting is the mainly confers and shrubs. Elevation is 50 to 800 feet. The muddiness caused by seasonal wetness. The use of average annual precipitation is about 45 inches, and the wheeled and tracked equipment when the soil is wet causes average annual air temperature is about 50 degrees F. The excessive rutting. Using low-pressure ground equipment can average frost-free period is about 200 days. minimize damage to the soil. Unsurfaced roads are soft Typically, the surface is covered with a mat of needles, When wet and are subject to deep rutting during rainy twigs, and moss 1.5 inches thick. When mixed to a depth of periods. Rock for road construction is not readily available. 6 inches, the surface layer is dark brown gravelly loam. The Equipment and logs on the surface result in a moderate upper 14 inches of the subsoil is dark yellowish brown �ery degree of soil compaction when the soil is moist and a gravelly loam. The lower 13 inches is dark yellowish brown moderate degree of puddling when the soil is wet. Carefully very gravelly_sandy loam. Grayish brown ortstein that laying out roads and skid trails, properly timing their use, crushes to very gravelly sandy loam is at a depth of about and using low-pressure ground equipment can reduce the 33 inches. Below the ortstein is grayish brown, dense degree of compaction and puddling. A moderate reduction glacial till that crushes to very cobbly fine sandy loam. The in producti�ity can be expected from unmanaged fires in depth to dense glacial till ranges from 20 to 40 inches. In undisturbed areas. some areas the surface layer is gravelly sandy loam. In Seedling establishment, seedling mortality, and the other areas the soil has 15 to 35 percent rock fragments in hazard of windthrow are the main concerns affecting timber the subsoil or is 40 to 60 inches deep to cemented glacial production. A low content of moisture in the surface layer till. during the growing season hinders the survival of planted Included in this unit are small areas of Beausite, and naturally established seedlings. Because most of the Everett, Lynnwood, Norma, and Ovall soils and Alderwood roots are concentrated in the organic mat, loss of this layer soils that have slopes of more than 15 percent or less than after logging greatly reduces natural fertility and the available 6 percent. Included areas make up about 15 percent of the water capacity. Reforestation can be accomplished by total acreage. planting Douglas fir or red alder seedlings. If seed trees are Permeability is moderately rapid in the upper part of the available, natural reforestation of cutover areas by red alder Alderwood soil and very slow in the ortstein.Available water occurs periodically. Seedlings that are planted or naturally capacity is low. The effective rooting depth is 20 to 40 established in the less fertile subsoil grow poorly and lack inches. Water is perched above the ortstein from December vigor. When openings are made in the canopy, the through May. In most areas, runoff is slow and the hazard uncontrolled invasion and growth of competing plants can of water erosion is slight. In areas used as pasture or delay the establishment of seedlings. Competing vegetation cropland, however, runoff is medium and the hazard of can be controlled by mechanical or chemical means. erosion is moderate. Because the rooting This unit is used mainly as woodland. It also is used as pasture or cropland. FIGURE 4 {CONTINUED) depth is restricted by the ortstein,trees are occasionally wheeled and tracked equipment when the soil is wet subject to windthrow when the soil is wet and winds are causes excessive rutting. Using low-pressure ground strong. equipment can minimize damage to the soil. Unsurfaced This unit is in capability subclass IVe. roads are soft when wet and are subject to deep rutting during rainy periods. Rock for road construction is not 2-Alderwood gravelly loam, 15 to 30 percent slopes. readily available. This moderately well drained soil is on glacially modified Equipment and logs on the surface result in a moderate foothills. It is moderately deep to ortstein. It formed in degree of soil compaction when the soil is moist and a dense glacial till. The native vegetation is mainly conifers moderate degree of puddling when the soil is wet. Carefully and shrubs. Elevation is 50 to 800 feet. The average annual laying out roads and skid trails, properly timing their use, precipitation is about 40 inches, and the average annual air and using low-pressure ground equipment can reduce the temperature is about 50 degrees F. The average frost-free degree of compaction and puddling.A moderate reduction period is about 200 days. in productivity can be expected from unmanaged fires in Typically, the surface is covered with a mat of needles, undisturbed areas. Steep skid trails and firebreaks are twigs, and moss 1.5 inches thick. When mixed to a depth of subject to rilling and gullying unless adequate water bars 6 inches, the surface layer is dark brown gravelly loam. The are provided or a protective plant cover is established. upper 14 inches of the subsoil is dark yellowish brown very Seedling establishment, seedling mortality, and the gravelly loam. The lower 13 inches is dark yellowish brown hazard of windthrow are the main concerns affecting timber very gravelly sandy loam. Grayish brown ortstein that production. A low content of moisture in the surface layer crushes to very gravelly sandy loam is at a depth of about during the growing season hinders the survival of planted 33 inches. Below the ortstein is grayish brown, dense and naturally established seedlings. Reforestation can be glacial till that crushes to very cobbly fine sandy loam. The accomplished by planting Douglas fir or red alder seedlings. depth to dense glacial till ranges from 20 to 40 inches. In If seed trees are available, natural reforestation of cutover some areas the surface layer is gra�elly sandy loam. In areas by red alder occurs periodically. Seedlings that are other areas the soil has 15 to 35 percent rock fragments in planted or naturally established in the less fertile subsoil the subsoil, has weathered bedrock at a depth of 40 to 60 grow poorly and lack vigor. When openings are made in inches, or is 40 to 60 inches deep to cemented glacial till. the canopy, the uncontrolled invasion and growth of Included in this unit are small areas of Everett, competing plants can delay the establishment of seedlings. Kanaskat, Lynnwood, and Ovall soils and Alderwood soils Competing vegetation can be controlled by mechanical or that have slopes of more than 30 percent or less than 15 chemical means. Because the rooting depth is restricted by percent. Included areas make up about 15 percent of the the ortstein, trees are occasionally subject to windthrow total acreage. when the soil is wet and winds are strong. Permeability is moderately rapid in the upper part of the This unit is in capability subclass IVe. Alderwood soil and very slow in the ortstein. Available water capacity is low. The effective rooting depth is 20 to 3-Alkiridge sandy loam,8 to 30 percent slopes.This 40 inches. Water is perched above the ortstein from moderately well drained soil is in cirque basins and on the December through May. Runoff is slow, and the hazard of adjacent valley floors. It is moderately deep to dense water erosion is slight. glacial till. It formed in volcanic ash, pumice, and cinders This unit is used as woodland. Douglas fir is the main over dense glacial till. The native vegetation is mainty , woodland species. Among the trees of limited extent are red conifers and shrubs. Elevation is 2,700 to 3,700 feet. The alder, western redcedar, western hemlock, and Pacific average annual precipitation is about 80 inches, and the madrone. The common forest understory plants are salal, average annual air temperature is about 42 degrees F. The Oregongrape, western brackenfern, western swordfern, and average frost-free period is about 120 days. evergreen huckleberry. Typically,the surface is covered with a mat of needles, On the basis of a 100-year site curve, the mean site litter, and moss 1 inch thick. When mixed to a depth of 7 index for pouglas fir is 146. On the basis of a 50-year site inches, the surface layer is dark brown sandy loam. The curve, it is 111. The highest average growth rate in upper 11 inches of the subsoil is dark brown gravelly sandy unmanaged, even-aged stands of Douglas fir is 153 cubic loam. The lower 19 inches is dark yellowish brown and olive feet per acre per year, occurring at age 60. brown very gravelly loam. Brown, dense glacial till that The main limitation affecting timber harvesting is the crushes to very gravelly muddiness caused by seasonal wetness. The use of FIGURE 4 (C�NTINUED) Site Development Associates, LLC SECTION 2 CONDITIONS AND REQUIREMENTS SUMMARY LANGLEY MEADOWS SECTION 2 107-016-006 CONDITIONS & REQUIREMENTS SUMMARY I 4 F.:_ s e `��$� 'i.�.E*�� - Site Development Associates, LLC TASK 1 - SUMMARY OF CORE REQU/REMENTS Core Requirement#1—Discharge af Natural Location The existing topography of the site can generally be described as gently sloping toward the east. Stormwater appears to follow the ground topography, and leave the site across the east property boundary. The proposed development calls for stormwater to be routed through a detention facility, which will discharge to the ` eastern property boundary, maintaining the natural discharge location. Hoquiam Avenue NE is located within a different drainage basin. Stormwater appears to follow the existing ditch and topography to the south. Within this basin we are proposing less than 5,000 square feet of new impervious surface, therefore not required to provide for detention or water quality for this segment. Core Requirement#2— Offsite Analysis A Le�el 1 downstream analysis was performed for the project, and is included in Section 3 of this report. A discussion of the upstream drainage area is also included. Core Requirement#3—Flow Control For the onsite basin, this project proposes the creation of a significant amount of impervious surFace area, and therefore, is subject to the flow control requirements of the King County Surface Water Design Manual (KCSWDM). Specifically, this project will be required to meet the Level 2 flow control criteria, as outlined in the KCSWDM. The design of the proposed flow control facility is covered in Section 4 of this report. Within the onsite basin, there is a small area that will bypass the onsite detention system (improvements along Jerico Avenue NE). This area will be compensated for in the detention vault calculations with a point of compliance calculation. There will be not net impact to flow duration downstream due to the project bypass area. We will be providing flow control for the adjacent short plat (Blessing). For the improvements proposed along Hoquiam Avenue, located within a different threshold discharge area, no flow control measures are proposed. The proposed improvements within this basin results in a net new impervious surface of less than 5,000 square feet. This area will be exempt from flow control standards per KCSWDM. LANGLEY MEADOWS SECTI�N 2 107-016-006 CONDITIONS & REQUIREMENTS SUMMARY w� �$; �, Site Development Associates, LLC Core Requirement#4— Conveyance Sysfem The proposed development will be required to meet the conveyance system criteria outlined in the KCSWDM. Specifically, the system must be sized to convey flows from the 25-yr design-storm event, and enough of the 100-yr design storm that significant flooding problems are not created. The design of the proposed conveyance system is covered in Section 5 of this report. Core Requirement#5— Erosion and Sediment Confro! In order to protect the downstream waters from erosion or sediment inundation, a number of Best Management Practices (BMP's)will be implemented throughout the construction process. These BMP's will include stabilization of exposed soils during and after grading activity occurs, installation of silt control measures (i.e. filter-fabric perimeter fencing, rock-lined construction entrance), and construction of a temporary sedimentation facility. Section 8 of this report will serve as the projecYs construction stormwater pollution prevention plan (SWPPP). Core Requirement#6—Mainfenance and Operations Maintenance and operations guidelines for this project are outlined in Section 10 of this report. Core Requirement#7—Financial Guarantees and Liability The project will be bonded per the City of Renton's guidelines prior to the commencement of construction activity. Core Requirement#8— Water Quality For the onsite basin, this project proposes stormwater treatment which meets the "Basic" water quality treatment criteria outlined in the KCSWDM. Specifically, the project calls for the construction of a permanent wetpool within the proposed stormwater detentionJtreatment vault. A further discussion of this facility, along with design calculations, are included in Section 4 of this report. Within the onsite basin, there is a small area that is bypassing the detention system (improvements along Jerico Avenue NE). The bypass area will be treated for water quality via a biofiltration swale before discharging to the wetlands. See Section 4 of this report for calculations. ' We will be providing water quality treatment for the adjacent short plat (Blessing). LANGLEY MEADOWS SECTION 2 107-016-006 CONDITIONS & REQUIREMENTS SUMMARY _�: � '�- � Site Development Associates, LLC TASK 2-SUMMARY OF SPECIAL REQUIREMENTS Special Requirement#1 — Ofher Adopted Area-Specific Requiremenfs This project does not lie within an identified critical drainage area, or other area for which specific drainage requirements apply. Special Requirement#1 is not applicable to this project. Special Requirement#2—F/ood Hazard Area Delineation This project does not lie within or adjacent to an identified flood hazard area. Special Requirement#2 is not applicable to this project. Special Requirement#3— Flood Protection Facilities This project does not propose construction of a flood protection facility, or rely on an existing flood protection facility. Special Requirement#3 is not applicable to this project. Special Requirement#4— Source Controls , This project does not require a commercial building permit or commercial site development permit. Special Requirement#4 is not applicable to this project. Special Requirement#5— Oil Control This project will not have "High Use" characteristics, and does not propose the ' redevelopment of an existing "High Use" site. Special Requirement#5 is not , applicable to this project. TASK 3- SUMMARY OFADDITIONAL REQU/REMENTS The project is not subject to any additional requirements in addition to the core and specific requirements listed above. LANGLEY MEADOWS SECTION 2 107-016-006 CONDITIONS & REQUIREMENTS SUMMARY I Site Development Associates, LLC __ __ _ I SECTION 3 '� OFF-SITE ANALYSIS LANGLEY MEADOWS SECTION 3 107-016-006 OFF-SITE ANALYSIS . _ �''-�- _ _ .. _____ . Site Development Associates, LLC TASK 1 — STUDYAREA DEFIN/TION AND MAPS II The project is located within the City of Renton, and consists of the following five tax parcels, totaling 11.09 acres: Property Tax Parcel Area Address Number (acre s) 698 Hoquiam 1023059113 2.39 Avenue NE No address 1023059151 0.35 listed 12208142" 1023059371 0.47 Avenue SE 12226142 1023059049 4.56 Avenue SE 12220 142" 1023059179 3.32 Avenue SE Total Area = 11.09 acres The off-site study area includes these parcels, as well as three upstream parcels, which lie adjacent to the southeast of the site. The study area also includes a large downstream wetland area to the east of the project site, and the remainder of the downstream flowpath to the southeast of the project site. Figure 5 of this report shows the general vicinity of the project site, and downstream analysis map. LANGLEY MEADOWS SECTION 3 107-016-006 OFF-SITE ANALYSIS # � __ Site Development Associates, LLC TASK 2- RESOURCE REVIEW Adopfed Basin P/ans (including Critica/Drainage Areas) The project site does not appear to be within an adopted basin plan area or critical drainage area. w Finalized Drainage Studies . No Finalized drainage studies were located in the vicinity of this project Basin Reconnaissance Summary Reports King County's Basin Reconnaissance Summary Reports were not consulted for this project. FEMA Floodplain/Floodway Maps The project site is shown on FEMA Flood Insurance Rate Map Number 53033C0982, and does not appear to be within a flood hazard area. A portion of this map has been included in Appendix 3-A. Other Offsite Analysis Reports This project is tributary to a large wetland area which exists immediately east of the project site. The recently constructed Shamrock Subdivision, which lies further to the east, is also tributary to this wetland area, and shares the same downstream system. The Level 1 downstream analysis for the Shamrock Subdivision has been included in Appendix 3-A. Sensitive Areas Folio Maps King County's Sensitive Areas Folio Maps have not been consulted for this project. The project site is not expected to contain any of the sensitive areas listed in the folio maps. Drainage Complaints and Studies No King County drainage complaints were researched for this report, since downstream complaints have already been addressed by the Shamrock Subdivision listed above, as well as other downstream projects referenced by the Shamrock report. Additionally, Langley Meadows is discharging to a large wetland area, which, �ANGLEY MEADOWS SECTION 3 107-016-006 OFF-SITE ANALYSIS �� Site Development Associotes, LLC in conjunction with the proposed detention facility, is expected to attenuate flow enough to avoid aggravation of any downstream problems. Road Drainage Problems No roadway drainage problems were identified in the vicinity. The existing roadway drainage along the site frontage appears to be operational and clear of debris. Migrating River Studies The project site is not within a Migrating River Study area. LANGLEY MEAD�WS SECTION 3 107-016-006 OFF-SITE ANALYSIS y �' Site Development Associates, LLC TASK 3- FIELD INSPECT/0N The Langley Meadows site and surrounding vicinity were visited on May 10, 2006. The conditions at the time of the visit were w�rm and clear, and no recent precipitation had occurred. No surface water was observed on the project site during the visit. The project site generally slopes downward to the east. Stormwater runoff appears to follow the existing ground topography, exiting the project site across the east property boundary. The east edge of the project is shown in Photo #1 below: ��,, ' � 'y c � A s a `I'�',,�; '� +'� � ; � r ,.� `�� "� �:� V�--�.-�: �r .. �^^ . a '�'<�:a� ,3 �� y ��"' ��d}� .��.�''i''�` � ' i � -'� '� 1Y `2'}"3 K -fS�`- 4� � 'y'�-<.± YJ�f��- � C .��`�» � _��'� ' ,- { » >>.�. .� . _ •�.,,�+ 'sa k - - ?' � '4 .. � t�� c_ s �r+.� . c�,s; ,i��y�__R�:.�.+ ' ��k�' '�': -_�6 �_ E R � ''` ,h�. ?A?� �� a -£�� *r� �.�e``-� . �-adF�,._ �- x- ' - r��'�,4r � ; �� ;� :�`. � +t� ' �� y T, , � 1 � � '-,�` ��'c , �C�- , e �,� . ''��'�"��'i. � `� � �i �4-� t��s.�- �. ') �g;4 � �'�� ..� � z�� t6' '4 � p„.y' �,�� r�" .��*� --�F�' ��- i� �� ' - �r -_��y♦ �;� �`�i�'�y��i,��"�.^. � 1 � .• .' N � --�-�e' s^Raimg„'ri� _ __ _ ��`�SZS �;�'3p� ,�'} _ i ' v � ' aryf..� -� -_ � j �a y . �. _.__ - l �%=Y -r� j �� ' . t ., .i .. _� µ� .. .� _ ' . , ". '__. ' _" -�� `}i�'�,t _ a : �, -_ _ - .."� �, "�� "�- ; � ...- - _. ,� � � - ;�. .. . � � .�-.,� �„. r ..� y . _ �''.:S�t6'�� , _ _ k. � �� _ 1�µf �� - � . �� . " � ... �:,_ :�- .. 6' . _ '-� �_ -. � . . ,.`�- . . � ` �' • _ _ - ' y , _�i `w$ .. . '.��C .aq: � . ' . . .. ��s`�.'._ 4. . Photo #1 (looking north along east boundary line) After leaving the project site, surface runoff enters a large, off-site wetland area which lies immediately east of the site. Photo#'s 2 & 3 show the vicinity of the wetland and project site. LANGLEY MEADOWS SECTION 3 107-016-006 OFF-SITE ANALYSIS M Cn Z c� O } H Q w Q �. ' � � ,�, '�� ,,�' �'a�,»;' ' Y, P...rec� �4 , ��n��'1^S� z t 9°'yy �.; ; t � "H 7"'°"� � � ,, :�c� �_��+�+ r ' k� r'�C.." � x r ' . a� 'TME"+� � . � . ��,��r 5�� ---�,.., •��'�x '�" '.S"� ��'C�.�,�€'e �^��'t i W ��i � �ya� �� C� y ��y� f r((yq A �� hs��k f��a�h�,.,,,^'i'ry��,�; � -�n�'�ay�� '�,d ry,,a:�:q^�'� L L k • �!IT+� t �'�� ` ' ' ,1t,�,�J`Y ��a �� tl ;'SAtU� j�tt L.aY.L". � � y�::��t'�, . �� r t°4Fk F �i��' ti�'�`,� ,� '.�, �ir$ : � �� y'r ,s, jr ��i u p�. �`" ,�''� �E. � � �, Y'4 � �+'�il �/ 'r' �„�r � • ? � �t � �� g w+�i ,m�r J�it �"° �" `"�a � 'n " � u , �� ti''�w c i^^�i�„� ��',,y%1��Ettr'�`�, +a. �i � *� * � �k r��'��"` �, . r �,o 'M1 �,�, � M1��kY'y'�`�"� � u ;; ��° � � � �: 'k' � b� � �' �i awr " r %11,'�� r '�,y ,-�: V�.. � r ��h�� { �'��' � ��,i"�, h^'��.�` ?�w+� � �# 'u: �. �3� � A C '��,+'�� '' �iq��'�we%k��'� k+�� 1 >f � . •"'�W4 k�k ��° � �� s"�� — � &� `Gv k'".�S z v:Wr�r� � , �r�r�7Y a '"v�. ai �1::� Y y, _ �� ,� "i� f � '�� 'aw. .� ' � �K�r,�,�: ��k�.�; . ��kn,t rt dF��'�"` kL � . �}� t�.. � � �. � �T{ ��` . � �� Y�D� .�0. h �,J�`T� � y �� ..6�.�, i'T � y � .��M� o � �r�rl�'� �a'yk r.cr��,a�l'�+'A4��`4 �$w;�� .,.1 '� � p:�� ` � � ,�' .� � . �a.. � ��,,� 4r��,�,A: � � .`� �.��. 1 s �t�� .� t� , I'� � � "O �!� r 6.� �x�� ,� tK�Y v - Y I� 4 k` ^r � �::'� �� A�� v'�t �`� ��,� dti�"� ��` n ttr r �UL � j,��y q«.. � C ^.x w.t e� � N o �r �� '��i r��'��`�s��t �'�� ,s�a � r'j�i fli "� M 3 � n _`.:� � '+ ��,� . �k � ''t. �;�'y'I4}y` �t f �x �4 �. y ,,.. `� a aa� ; O O tn w • �. � � f. i „g,�. \�, O (D � �j A4 F�` � `: . 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J "� ��'�S � } �- � `.: ._�- Tr f'Y O �'.� �. d x h`s'��' A';s � '�'" �� i a �' 1, �M, � 4F' w .�' w? �� x,:� ��"'i`2� � .�� ..,.� � 'l. �j p 'ta'��, 1w� 1�� u. d�,n � r �,�. �� • n+ � 1,,� .;� � �' � r�� ;1 . .s.+ y�'`�' �h,,1 '�'t ° . . �4.�' . � Q t4.�y��p��y��l�r., � ��'' �r�� "� �•�p�td4.��'�� ,w�r�s 7 � � +' � �^ 'j� �.,� 4 �'i„'iYha P��7'y,�� Q u h ,� a `t. #�'F J aw° �A? x „ ? 1r �k�. � �{�� W tn u'� . W �� : r ,�+,�,�* .. ' �i�`�� p � �, ��, • � `� �� t}��ti '��"'r"i.� f �� Y�w�ts+� jx 7 �r M1 �":dr��X �,�� " �' �" ha Q �� q b�":�n'. � 1 � t }�� . �'�F ` (�� 1 •R�/{,�, aA� 2 t w�'r y ��. 1 �... . � n��,:�k�'x� 77 � C� y_. ' •�� i't, ..� ry�. . � �s- yI�F�^ lM ;j *L .Y� W . �i I�' 4 e0�'y, h ,�� O � '� .,,... h �T �'�` �'��G � ', "'�` �, . �P� - `yY d � �„ W Q � , +a. /�� '�', ' p't�,,rr' F ;��/.%'i,�� j+; P �rY'i�' �r" J CD � � � � 'q:l Z �M��`l A F� y '�vr" �'1 '� •_ O '�� , 3t 7'.� ) d. ?,�..L h -4;� V � ��.� .i 'Hf��,�4�;�� w 'R1..+�N�„tT,'y Z , a. .. :,,w,¢° ," / .�� I�{r' �:''�w u�G�� U�r+ ' � . , .�_ ��..'1i�`� !. . :� > ;i Q O : . � J NI 1� � ,� N � } i�i '. � _ Site Development Associates, LLC The wetland system continues to the south, and runoff follows the same downstream flowpath that was outlined in the approved downstream analysis for the Shamrock development. The Shamrock downstream analysis has been included in Appendix 3-A of this report. The exhibits in the Shamrock report have been modified slightly to show the location of the Langley Meadows site. Three single-family residences lie immediately adjacent to the southwest corner of the project site. A portion of these lots, specifically the back yards, appear to be tributary to the project site. All three lots face 142"d Ave. SE, and it is likely that the roof and footing drains from these lots drain toward the fronting road. � ' ' TASK 4- DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCR/PTIONS No specific problems were noted on the Langley Meadows project site itself, since the primary method of conveyance is overland sheet flow. Immediately off-site, stormwater runoff enters a large wetland area, which appears to have been recently enhanced during the development of the Shamrock subdivision to the East. Any problems that may have existed downstream of the wetland area are assumed to have been resolved as part of the Shamrock development. TASK 5—MITIGAT/ON OF EXlSTING OR POTENTIAL PROBLEMS No specific problems were identified during the site investigation. The detention facility should outfall to a rock-lined splash pad, to keep erosion in the wetland area to a minimum. LANGLEY MEADOWS SECTION 3 107-016-006 OFF-SITE ANALYSIS ,� �"' � II . � �� Site Development Associates, LLC __ . APPENDIX 3-A RESOURCE REVIEW DOCUMENTS , I LANGLEY MEADOWS SECTION 3 107-016-006 OFF-SITE ANALYSIS ' A B C APPROXIMATE SCALE IN fEET I 500 0 500 122°09'22" JDINS PANEL OG69 47°10'00., __ __ ._ —__'_._. --__ .._..__"._'_____. . .. .__— —_ ._._ i CITY OF RENTON soun+t:nsi nsTH S7qF.ET KING COUNTY F' 1 NATIONAL f100D INSURANCE PR06AAM I` w � a � �° FIRM SOUTMEAST �1BIH S7�EC7 - � FLOOD INSURANCE RATE MAP I CITY OF REN7'UN KING COUNTY, 530088 WASHINGTON AND INCORPORATED AREAS SOUTHEA'�� 12nfM `.�HF.ET PANEL 982 OF 1725 ISEE M/��INIJE%fOR VANlLS N�ll PRiNTFfI) I �UUTHfA"T 1215T STREET _ CONTNNS. COMMUNIfV NUMBEfl PANEI SUFFI% _—. __ __"_ _. _ ._ _ I K�NN courm I� u n,convon�.[o<neas c�mn oce7 r r.H��n.tmor �a�e wux r ZONE X � o } P n�'Fc: ! 2 o z z 10 S'�� il w � � �I� I rt u v KIN CITY OF RENTON UNINCOR MAP NUMBER 53033C0981 F 530088 MAP REVISED: � � �.r_ MAY 16,1995 SUVIHtP,SI t]RT11 STREET � f ,S .�` w � Federal Emergency Management Agcncy � I g Tni.�..�oinoir oow a.wn�oo w m..eo..�w.�w nom m.P■ v��xlncl�d u�np P-MR OmLlne. 1H�m�p��wl r�ll�cl c��npw 1701 I I ;TliffT ar�m�nam�nn <n m. n�.a iv�n mw�• pu�nl le In�ax�on�M $OUTMFAST tltl�tl¢4.For 1��I��r�prodc<IMorm�llm�Eo�1 N�11mY FIooC Ir�ur�rc� �rop�m Ilootl m�p�cMck tM fEMA�Ioatl Mep 61ore e�v.ww m�c Nm�.pov Shamrock �� LEVEL 1 DOWNSTREAM ANALYSIS � � � King County, Washington Prepared For: Prepared For: CamWest Real Estate Development, Inc. Issued July 29, 2002 Revised September 12, 2003 Re�rised January 19, 2004 Revised l�-1ati� 26, 2004 <vCC° W ��,.�,5''s' � �tl � '� ''° y ff , r z � � r r' '�' 7359 �` /STER�� -I .S�QNAL ti`�V _ ��'l � IXPIRES i1/15 .� Prepared By: Schwin Chaosilapakul Ben Rutko«ski Reviewed By: Rebecca Cushman, PE Shamrock—Levei 1 Downstream Analysis Table of Contents I � 1 INTRODUCTION.................................................................................................1 I 2 SITE....................................................................................................................2 3 UPSTREAM DRAINAGE ANALYSIS.................................................................2 ' 3.1 Upstream Basin ................................................................... ............... 2 ................................ 4 DOWNSTREAM DRAINAGE ANALYSIS...........................................................3 4.1 Onsite Runoff...................................................................................................................... 3 4.2 Offsite Runoff...................................................................................................................... 4 4.3 Downstream Capacity........................................................................................................ 4 4.4 Downstream Drainage Problems...................................................................................... 7 5 RESOURCES USED FOR ANALYSIS...............................................................8 5.1 Sensitive Areas Folio......................................................................................................... 8 5.2 King County8asin Reconnaissance Program................................................................ 8 5.3 Soils Survey for the King County Area ............................................................................ 8 , 5.4 King Counfy Community Planning Aiea.......................................................................... 8 , 6 DRAINAGE CONCEPT.......................................................................................9 � Appendix.................................................................................................................. A Existing Conditions Exhibit Developed Conditions Exhibit Dolvnstream Dr-ainage Exhibit Tributary Areas E_xhibit Soils Map and Legend, Hy°drologic Soils Group Table Sensitive Areas Folio King County Basin Reconnaissance Program King County Community Planning Area Complaints Excer�t fi�orn Siertnrr I�riprovement Plat�s (6 Sheets) � Shamrock—Level 1 Downstream Analysis �I 1 INTRODUCTION Shamrock is a 34.5 acre site spanning both King County and the City of Renton jurisdictions. The total proposed project will contain 129 lots. The King County portion of the project proposes to create 118 single-family lots (74 lots ��ill utilize Low Impact Development} on II an approximately 29.8 acre property. This Technical Information Report (TIR) is for the King County and Renton portions of the project. The Vicinity Map belo�� shows the City of Renton boundary. "The part of the site outside the City of Renton boundary is subject to King County DDES revie��. The site is north of 128'h Street SE, west of 148ih Avenue SE. The property is within Section 10, Township 23 North, Range 5 East, W.M., King County, V��ashington. Please see the I%icinity�'�1ap belo��v. I , , � � ,� �� I � r�� , `��i � !��ol � ,�,.� � i MAY VALi£ F{_. � � �OUPf i Y PA,9K -p . � �y A T� � � , I � ��s - � �o� � �o , Q SE i76th S7 I �SE 1771h �u ,� a sr � sOG`i W ��" � � � Q � �, �t SF ;POth r �.i . Q � ST � Q �, � ` L I � I I ` � / � � COALFEILD �74th �� PAftK. c�=vWi � 1 KIN_ 'Clv'_T" s>�� e ` Y Q—a——` ? h PARK TO I—4 5 REN";^J � h h . 1 � p & I NE 4 t.h S T � R�Df -j '�Sf TE � i � 4 � — � y SE r37nd 57 I I �� SE �JJra C7 i � � T� �I � , -� i _i �---, � , , -- i—� �—I-� �--� � ,' i �J I � i i �'ICINITY 1��AP ,'�'ot to Scale Site ��isits were perfonned on July 2, 2001 and July 1�, 2002 and July 14, 2003 to obsen�e t11e upstream and do«�nstream drainage conditions. The following analy°sis is based on these site �-isits and related research of available records. May 26, 2004 Page 1 Job #01-159 �TRIAD � �.,� . Shamrock—Level 1 Downstream Analysis 2 SITE The existing site is a wholesale nursery��ith tvvo residences and several outbuildings that will be demolished (see Existing Conditions Exhibit, in Appendix). The site generally slopes from the east to west. An onsite wetland exists on the northwestern portion of the site. Slopes range from 2-12 °%with pasture ground cover. The site exists within t«�o basins. 3 UPSTREAM DRAINAGE ANALYSIS 3.� Upstream Basin There are several upstream areas that are tributary to the site. Areas 1 and 2 are tributary to the portion of the site that is �;ithin the l��ia_y Creek sub-basin. Please see Section 5 in the Technical Information Report (TIR) for detention/��vater quality issues. Area 3 is tributary to the Lo«�er Cedar River sub-basin portion of the site located in both King County and the City of Renton. Please see Section 5 in the TIR for detention,��vater quality issues. :'�-ea 4 is tributary to the ��etland only and ��ill not affect drainage. Areas S and 6 were previously assumed to be tributary. Ho�;-ever, additional topography revealed that it is not tributary. I, Upstream from the southeast section of the site is a development called Morgan Place which contributes approximately 3 acres. I The site contains slopes ranging from 2-10°/o, predominately in the westerly direction consisting primarily of pasture, some light forest, wetland and two existing houses. Refer to the Tributary Areas Exhibit at the end of this report. May 26, 2004 Page 2 Job #01-159 �TRIAD � . . �_, Shamrock— Level 1 Downstream Analysis 4 DOWNSTREAM DRAINAGE ANALYSIS Refer to the Doivnstream Drainage Exhibit and Upstream Tributarv Map from the Loken/Johnson Report, Sheets 1 and 2 from the approved King County Project L02SR037 and Sheets 10, 11 and 15 from the appro�-ed City of Renton Project of Sienna at the end of this report. 4.1 Onsite Runotf North Approximately 17.0 acres of the northern portion of the site slope from east to «�est. Slopes range from 2-12 %. This northem portion of the site is tributary to t«�o onsite wetlands located in the north�;-estern portion and north-central portion of the site. The northwestern «retland discharges to the north and south, ��-hereas the north-central «-etland discharges to the north onlv. South The remainder of the site drains in a south«est to south direction over gentle slopes. Runoff is collected in an existing detention pond located north of the intersection of SE 128`h Street and 146th Ave. SE. Specifically, at the southeast corner of the southernmost parcel of the site. Runoff from the pond discharges south offsite beneath SE 128�h Street through a 42- inch pipe. May 26. 2004 Page 3 Job #01-159 � ITRI.� � �...�� . Shamrock— Level 1 Downstream Analysis 4.2 Otfsite Runoff North Discharge from the north half (+/-) of the onsite northwestern wetland flows offsite to the north through a 12-inch CMP and a 6-inch concrete culvert and into a pond in the adj acent property. The pond discharges north into a wetland, then to Honey De«� (Honey) Creek which, according to the December 1990 King County Sensitive Areas Map Folio, is an unclassified stream in the May Creek Sub-Basin. The north-central wetland discharges to the north and connects with the off-site „-etland described above. Honey De�� Creek combines �vith May Creek over h��o miles downstream (north) of the site. May Creek is in the Cedar River Drainage basin and ultimately discharges into Lake Washington. South Runoff to the south flows through a 42-inch pipe then into a ditch behind a residence at 14415 SE 128th St. The ditch ranges from 2 to 3 feet deep and then travels under a driveway via an 18-inch culvert. The storm water enters the north property line of a ne�i� development (Sienna). The flow is then picked up by the 36-inch by�pass conveyance pipe within the Sienna development and continues in a southerly direction until passing the quarter-mile downstream point at its intersection �vith SE 132"d Street. From there, the flow continues to travel in the 36-inch pipe approximately 200 feet «�est on SE 132"d Street before changing course to the south on 144`h Avenue SE. The flow then travels south on 144'h Avenue SE for approximately 600 feet «�here it connects to a 24-inch cross culvert. The flo�� then continues to the vvest in a defined stream channel. 4.3 Downstream Capacify The Sienna project included the design of an upstream b��pass conveyance line. The sizing of this pipe system «-as based on assumptions made of the upstream basin. These assumptions ��ere made based on limited topography. As a result of more detailed topography, it is found that the original assumptions are conservative. Please see the Tributary Areas Exhibit located at the end of this report. May 26, 2004 Page 4 Job # 01-159 �TRII�D �, ,. . Shamrock-Level 1 Downstream Analysis The following is an excerpt from the Final Corrected Technical Information Report provided to King County under Permit#L02SR037 dated September 16, 2002. Begin Excerpt Conveyance for Upstream Flows The KCRTS 1 J-mir�iute time step lras used to dctef-rnine the ovef•all flotivs tribrctar�� to the pipe sl�stern conveyance. 67.2 acres upstreum urea has been recently developed. Those areas J�c�rtaining to new development were modeled using the information obtained from previous Technical Information Reports. 77�e rernaining areas were rnodeled using approved Technical Inforn2ation Reports, Aerial maps and actual sun�ey. All of NE 4`h Str-eet righl-of- iray> was assumed impen�ious. An additional 7.81 cfs from the 1 DO-year outflow of the cletention pond from the City of Renton approved project of Sienna was added at CB 4 f�i�iking the total floivs piped at ?5.41 cfs. Please see the upstream tributary nrap. The follotiving is the gr-ound cover breakdoivrt of the 159.43-acre tributan�area upstrearn and the I�'CRTS 1�-minute time step prirttout. Till Forest: 74.94 acre i��'etland.� 4.81 acre Till Pasture: 9.76 acre Impen�ious: 36.06 acre Till Gr-ass: 33.86 acre Flow Frequency .�zialysis Time Series File:jan28. tsf Project Location:Sea-Tac --Annual Peak Flow Rates--- -----Flow Frequency Analysis------ Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Peri od 20.50 6 2/09/O1 12:30 67. 60 1 100.00 0.990 14.40 7 1/05/02 15:00 44.13 2 25. 00 0.960 44.13 2 12/08/02 17:15 25. 62 3 10. 00 0.900 13.82 8 8/23/04 14:30 24.49 4 5. 00 0. 800 25.62 3 11/37/04 5:00 21.65 5 3. 00 0. 667 21.65 5 10/27/OS 10:45 20.50 6 2. 00 0.500 24.49 4 10/25/06 22:45 14.40 7 1.30 0.231 67. 60 l 1/09/08 6:30 13.82 8 1.10 0. 091 Computed Peaks 59. 78 50. 00 0.980 This conveyance system has been designed to convey flou-s up to the 100 year storn� without o��er�topping. May 26, 2004 Page 5 Job #01-159 �TRr�v � �� , Shamrock-Level 1 Downstream Analysis Freeboard Tables from Storm Sewer Output Upstream Tributary Pipe S�•stem Catch 8asin Rim Elev. HGL E/ev. ``Freeboard outfall-1 410.00 409.08 0.92 1-upstream 410.00 409.10 0.90 ' 2 415.80 409.96 5.84 3 420.10 411.96 8.94 4 421.84 419.37 2.46 5 428.50 423.27 5.23 � 6 430.65 424.72 5.92 7 431.32 425.43 5.88 8 432.52 429.49 3.02 9 433.00 430.17 2.82 10 439.25 430.88 0.37 End Excerpt Additional survey and analysis of the onsite «�etland located on the west property line of Shamrock determined that approximately 22 acres of assumed tributary area to the bypass conveyance system flo�vs to the north as apposed to the south. Therefore, the desigr►ed flows to the bypass com-eyance system are more conservative w�ith less tributary area. � May 26, 2004 Page 6 Job #01-159 �TRIAD � Shamrock—Level 1 Downstream Analysis - 4.4 Downstream Drainage Problems North According to King County Water & Land Resources Division, there have been no recent problems do«�nstream of this project. The complaints that have been documented are associated with do«�nstream properties near the East Renton project. These complaints are over 12 years old. King County suggests not following up on any complaints before 1990 due to their age, development that has occurred, etc. Additionally, no complaints have been documented at those addresses for 12 }•ears, so the problem most likely has been conected. The complaints are linked to a private home drainage system and a private road �;-ashout due to no drainage system rather than flooding, or erosion of the large drainage course that our site will discharge to. Since no complaints have been documented at this location in the last 12 years, it is assumed that corrections have been made as a result of subsequent development. South According to complaints compile�l by the King County Water and Land Resources Division, se��eral instances of flooding have been reported in areas near the downstream drainage path of the site. Problems of flooding and drainage in these areas seem to have been alleviated with the recent installation of a 36-inch pipe system shown in the Downstream Drainage Exhibit. Details of complaints are included at the end of this report. Since the installation of the 36-inch conveyance system there has been one downstream complaint. This complaint comes from the resident at the address of 5511 NE 2nd Street. The resident complains of the roadside ditch overtopping. Per conversations with Ron Straka with the City of Renton, this is not considered a major issue and the City currently does not have plans for maintenance. In addition, available topography suggests that potential over- flows from the Sienna project would flo�� east along 3rd Street to Lyons Avenue, then south along the west side of Lyons Avenue rather than further east to the subject property. A copy of this complaint along with photographs can be found in the Appendix. Also see the Do��istream Drainage �1ap �? included at the end of lhis report. May 26, 2004 Page 7 Job #01-159 /T'RL�I� � , � � � _ � a � � E: \PROJEC� '159\DWGFi/es\Engineering Exhibits\LEl/EL 1\01159 L 1—EC.dwg, � I � � , � > > � I � �u � � �,:�� i ± n � � , , t ! �I I�; ._._.__ � �. �.:.. , : , . . . . . . . . . ..,� {,� { � � � �� ' `, ,� • � � �� - 'ti E 1 � ' . � '' t t.� � , r'C�. 1 t-+-- -t- ' '�---` �— i- -:- � � ......__. . 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DATB ean9�on er cK DEVELOPED CONDITIONS � �� '�� EXHIBIT � S`� � �� ;�� a�� CAMWEST � gti� yy� � �� " �p � ��= �� N � e� � � SHAMROCK 8 Q�€ �i � ,� (� � LEVEL 1 DOWNSTREAM ANALYS/S 3 � � m �O > „�� KING COUNTY, WASH/NGTON SECTION 10, TOWNSHIP 23 NORTH, RANGE 5 EAST, W.M. � � � � � � .� � � � � =' � � �, TRIAD ASSOCIATES _- _ _ _� ��-�J:I ,��`F.��- _ __ _ � ONSJT� TR/BUTARY AREA _� -� — � ._.�.>;�:� �Y��==-��P - ��.=�2__ ,.' �- - -� � ' � � . -�� _ j- — —— � A_34.5 ACRES ,,.,.,,�,�,..� — f — — — - N18K ia+e.+4wxom�-�m — — — — - - - - - - f-�-�—— — — — — OFFSII'E TRIBUTARY AREA 425.�,.� , , �.. . _ , __ - . , , , , - . � _ C - . l :�•. - .� ': �.-,' � ,` ...._. . ��.._ .��,_. , . _.__ �..�.��. . , _ __- .: ,u.�,.�,� _ �: � - : - ., - :- , _ . . - � _ .. , --.�. _. _ V A 10 8 ACRES . �� . . � : ,.. _.. � = . - -- ..�--r-�� . : `�.- - �- . � � _ � ; � � �_ - - - _. 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':- �.�'! --_��: -�'�.- -- . . � PAOJBCT SURYEYOR - ... _ . -- _ .: .. \ � .... . . - ----- --- ...__ � � - ' - ' - /�� . . �. . - . .. 3S 3AY Hlt►I P�LNCNI ELkK � / � PRO1HCf IANDSCAPB ARCHITECf .0 ' , � � FlR�SUB�ALD� v�t.: N - . �o, AREA PREVIOUSL Y ASSUMED TO BE �u TR/BUTARY TO S/TE (TYP1 � h - a� ' � _ " , o �;� � :�, _;� - � _ c � _ ,� � � •-- c.� � _ sr.1rF vcr cAuo � UNLESS SIC�'ED AND�ATEU � � SCALE: 1"= 200� '°°"° 01-159 � . � � - �He�Na. 3 4 ��pQ4 TRIA.D ASSOCIATES ov � TRIAD � ASSOCIATES '�. _ i � �� . . � � �C.WA eE011E97! .. 125.821.844B szs.ezis�ei� � I I �o..ae.wss a b. I �� - - - - - - -� - - - - I I I 1-1-T�' I I � � z � --� I �� t�' - o II - - -- - - - -- I _ � � ° i � �� 1J�L � � � � � � �l I = -- ; � ��_ I � T- --I� - - � I � � Q � � � ��—T T � � � � � � 3 � � i i� i� i� ��,—,-- �--�--�---�-�---� i i P � I � � Q �C z i i i i i� � � `_ � � � � — 1-- - - -- -�-- --� � _ � v � 148TH AV - - - - - - _ Q � � �� _ _ �1-I� � I� � -1 f-- --� -I � - - - - - Q � � � � � " ' � � � ��- I � � I � I I � I Q � � � & �- � r-� � i i � Ww Q � Z � vQ3 � � � � . � �-- -� � � � o � �� , � I ► � � = A �f --► � _ .�� , �— � - � � ' ' I I ' ° y � � :.:.:-.. � � i-T -r—i— �� - , , � I I I > > � .� : S/TE � "� 14$�H — � �—L,�_L - - - - - - � i . �. � ,. �-�.r. � � . .� . �� . � � - I �I�T� T - - -T - - - � ��:..---�� = . .� : . � SI TE � -� �--� -�- -� �-- � � i i � - — � :- : : • '+ 120'—42" � � � i �� I I I I � Y � ._.. • . • . : � ' � 34.� . . '_.` . '.;., . . — _ ��——�— � I I I . . . � � . _ : , � � I � I � —� I �:�:��WLC:7'CA�.� .: �� —— — — — �— � ' � 1/4 M/ P /NT � �. ' . I � � i I I � L EX. 24" INfAKE I .•:•:•:•:•:•:�:•:•:�'�'�'�'�' - l� - � 1�� . - � ��;;-��;�<i ! / -�--— — - - — - _ =_- = ��y �/�/ � ,� ��-�,�rs�-,- ��ri— �—� �-� � �-- - -� � � ' i --I , ,�.�,�� _ + ► � —� C I I I � � I I � I EX 24- OU�ALL � ;� I—— � �--I L J I I I_� —I — � � :� — � I �-�— � _ �_ I ' � � �`�c� I � � i � �� r� � � � �� _ � --� � I I exaacr a�cn+eaa � � , . — ��— J II � —7 ��— ——— —� I I I i PRWYCT IAN0.SCAP6 ARLIIRLLT _ I FlRSI SUBYRIAL YA1R: • _ —_ _ � — — — �� __�_ SCAI$ AOR2:1'�Idp' IOR_N/A �— ---r —� , —— ——� —— � --� �----- — — � � � �— _ � ' �� _ — � r� _ �—�— ► � � � � _ —1 I—---f—� z I �� ► _� IC� � TOTAL S/TE AREA � 34.27 AC _ � � (— � I � I � � � �� r_ SCALE:1•= aoo� , � ..,... _. � _. � . .. .. , .._,_ ,, _ �� _ � � I I --+ � � ' ! Fcow cE�vo , — I i � I i I PIPE fLOW � ,,,''� Si�IfET FLOW , I_ � I I SIAYP!70T 1'Al1D L _ � _� � I I i . . � Si�IALLOW fLOW UNIECS SIGNED AND UITBD arcH Fcow '°B"° 01-159 I �� I, _ _ _ sxeer n�a. ' C�2004 TRIAD ASSOCIATES 4oq4 J �' •� -- _ � _ _ ___ Site Development Associates, LLC SECTION 4 FLOW CONTROL & WATER QUALITY ANALYSIS & DESIGN LANGLEY MEADOWS SECTION 4 107-016-006 FLOW CONTROL &WATER QUALITY FACILITY ANALYSIS & DESIGN � Site Development Associates, LLC PART`A'— EXISTING SITE HYDROLOGY The existing site topography can best be described as gently falling to the east. The existing land cover consists of a handful of single-family homes, detached garages, and driveways, surrounded by landscaping and lawn area. In the existing condition, stormwater runoff is expected to follow the existing ground topography, and flow overland to the east. The existing drainage basins and site hydrology are outlined in Figure 3a & 3d of this document. PART`B'— DEVELOPED SITE HYDROLOGY The proposed development calls for the installation of an underground pipe network to collect and convey flow from the surface streets. All roof and lot runoff is intended to be directed to this system. The pipe network will convey surface runoff to an underground stormwater detention and treatment vault near the east edge of the site. The vault will contain live detention storage, as well as a permanent wetpool for storrnwater treatment. Detained and treated flow will be discharged to the existing off-site wetland area. The proposed drainage basins and site hydrology are outlined in Figure 3b � 3c of this document. PART`C'— PERFORMANCE STANDARDS The proposed detention facility has been designed in conformance with Level-Two flow control standards, as outlined in the 2005 edition of the King County Surface Water Design Manual (KCSWDM). The level-two flow control standard essentially stipulates that the peak flowrates and peak flow durations in the post-developed condition shall not exceed the existing peak flowrates and peak flow durations. This condition shall be applied to flowrates ranging from %2 of the 2-yr design storm to the 50-yr design storm. j In order to simplify the facility design process, the peak release rates are allowed to exceed I� the existing flowrates as long as the exceedence is not greater than 10%, does not occur for more than half of the analysis range, and does not exceed the existing flowrate at % of the 2-yr storm event. I ' Design of the stormwater detention and treatment facilities will be performed using King County's KCRTS hydrologic modeling software. LANGLEY MEADOWS SECTION 4 107-016-006 FLOW CONTROL&WATER QUALITY FACILITY ANALYSIS & DESIGN -,��- �� Site Development Associates, LLC PART `D'— FLOW CONTROL SYSTEM Flow control for this project will be provided by an underground detention vault. A detail of the detention vault is included in this report. Design of the detention vault is performed as follows: Step 1 —Determine the pre-developed hydrologic condifions: ____ _ ,: __ _ _ _ _.- - - - �, . ; . z � �� - ��' - �� ; Area ? Till Forest 4.29 acresl Till Pasture' 6.80 acres' Til[ Grass 0.0� acres' Qutwash Forestt O.U� acres Outwash Pasture 0.00 acresi Ouiwash Grass O.OQ acres' ti+Vetland, 0.00 acres Impervious; 1.3U acres __ _ _ _ _Total ____ _ _ 12.39 acres ___ --------- Scale Factor : U.8� Hourly Reduced Time Series: predev » Compute Time Series � Modify User Input � _ _ ----- _ - - _ ___ - -- __-- __._ _ __. File fior computed Time Series [.TSF] Flow Frequency A�al;sis Time Series File:predev.tsf Project Location:Landsburg --Annual Peak Flow Rates--- -----Flow Frequency Analysis---- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 1.11 3 2/09/O1 14:00 1.95 1 100.00 0.990 0.367 S 1/OS/02 16:00 1.12 2 25.00 0.960 0.791 4 2/28/03 16:00 1.11 3 10.00 0.900 0.728 6 8/26/04 1:00 0.791 4 5.00 0.800 0.742 5 1/OS/OS 10:00 0.742 5 3.00 0.667 0.603 7 1/18/06 16:00 0.728 6 2.00 0.500 1.12 2 11/21/06 9:00 0.603 7 1.30 0.231 1.95 1 1/09/08 7:00 0.367 8 1.10 0.091 Computed Peaks 1.68 50.00 0.980 LANGLEY MEADOWS SECTION 4 107-016-006 FLOW CONTROL &WATER QUALITY FACILITY ANALYSIS & DESIGN � _ - .. Site Development Associates, LLC Step 2- Determine the post-developed hydrologic conditions: _ . _ _ ? , � - � Area , ? Till Forest! O.OD acres � ; Till Pas#ure', O.�U acres � Till Grass� A.59 acres; ; Outwash Forest O.flO acresi Outwash Pasture O.QQ acres' Outwash Grass 0.00 acres Wetiand O.OQ a�res Impervious 7.23 acres; -Total ------� 11.$2 acres� ------- Scale Factor : �.80 Hourly Reduced Time Series: de� �y Compute Time Series � Modify User Input � _-- _ --- _- --_ - _ _ --- _ _ _ __ -- File far computed Time Series [.TSF� Flow Frequency Analysis Time Series File:dev.tsf Project Location:Landsburg --Annual Peak Flow Rates--- -----Flow Frequency Analysis Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 2.41 6 2/09/O1 2:00 4.36 1 100.00 0.990 1.46 8 12/03/O1 17:00 2.91 2 25.00 0.960 2.47 4 9/10/03 15:00 2.84 3 10.00 0.900 2.84 3 8/26/04 1:00 2.47 4 5.00 0.800 2.34 7 10/28/04 18:00 2.43 5 3.00 0.667 2.43 5 10/22/OS 17:00 2.41 6 2.00 0.500 2.91 2 11/21/06 9:00 2.34 7 1.30 0.231 4.36 1 1/09/08 7:00 1.46 8 1.10 0.091 Computed Peaks 3.88 5o.00 0.980 LANGLEY MEADOWS SECTION 4 107-016-006 FLOW CONTROL &WATER QUALITY FACI�ITY ANALYSIS & DESIGN � _ -- _ . Site Development Associates, LLC ? . � � � � -Area _ ; � Til! Forest 0.00 acres Till Pasture� 0.�0 acres Till Grassl 0.25 acres; Outwash Forest 0.00 acres� �� Outwash Pasture' 0.00 acres" Ouiwash Grass a.00 acres 1�letland �.0� acres; tmpervious 0.32 acres ___. _. __ _-- -Tatal------- U.57 acres _ ___ - ----- Scale Factor : 0.80 Hourly Reduced Time Series: bypass >] Compute Time Series � Modify User Input � _ _____ _ _- --__._ _. __ __ _ _ __ __ __--- _ _ -_ --- Fife for computed Time Series [.TSF] Flow Frequency Analysis Time Series File:bypass.tsf Project Location:Landsburg ---Annual Peak Flow Rates--- -----Flow Frequency Analysis Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.113 4 2/09/O1 2:00 0.206 1 100.00 0.990 0.066 8 12/03/O1 17:00 0.136 2 25.00 0.960 0.111 5 9/10/03 15:00 0.130 3 lO.OQ 0.900 0.130 3 8/26/04 1:00 0.113 4 5.00 0.800 0_107 7 10/28/04 18:00 0.111 5 3.00 0.667 0.111 6 10/22/OS 17:00 0.111 6 2_00 0.500 0.136 2 11/21/06 9:00 0.107 7 1.30 0.231 0.206 1 1/09/OB 7:00 0.066 8 1.10 0.091 Computed Peaks 0.183 50.00 0.980 �`' i LANGLEY MEADOWS SECTION 4 107-016-006 FLOW CONTROL&WATER QUALITY FACILITY ANALYSIS & DESIGN � _ � .�� . -- --_ Site Development Associates, LLC Step 3- Calculafe fhe required defention facility dimensions: Type of Facility: Detention Vault Facility Length: 910.40 ft Facility Width: 20.00 ft Facility Area: 18208. sq. ft Effective Storage Depth: 5.50 ft Stage 0 Elevation: 448.00 ft Storage Volume: 100144. cu. ft Riser Head: 5.50 ft Riser Diameter: 18.00 inches Number of orifices: 2 Full Head Pipe Orifice # Height Diameter Discharge Diameter (ft) (in) (CFS) (in) 1 0.00 2.81 0.526 2 3.50 3.50 0.525 6.0 Top Notch Weir: None Outflow Rating C�rve: None StaqelStoraqe/Discharge Performance Stage Elevation Storage Discharge Percolation (ft) (ft) (cu. ft7 (ac-ft) (cfs) (cfs) Stage Elevation Storage Discharge Percolation (ft) (ft) (cu. ft) (ac-ft) (cfs) (cfs) 0.00 448.00 0. 0.000 0.000 0.00 0.03 448.03 546. 0.013 0.037 0.00 0.06 448.06 1093. 0.025 0.052 0.00 0.09 448.09 1639. 0.038 0.064 0.00 0.12 448.12 2185. 0.050 0.073 0.00 0.15 448.15 2731. 0.063 0.082 0.00 0.18 448.18 3277. 0.075 0.090 0.00 0.21 448.21 3824. 0.088 0.097 0.00 . 0.23 448.23 4188. 0.096 0.104 0.00 0.33 448.33 6009. 0.138 0.124 0.00 0.43 448.43 7829. 0.180 0.141 0.00 ' 0.53 448.53 9650. 0.222 0.157 0.00 0.63 448.63 11471. 0.263 0.171 0.00 0.73 448.73 13242. 0.305 0.184 0.00 0.83 448.83 15113. 0_347 0.196 0.00 0.93 448.93 16933_ 0.389 0.207 0.00 1.03 449.03 18754_ 0.431 0.218 0.00 1.13 449.13 20575. 0.472 0.229 0.00 1.23 449.23 22396. 0.514 0.238 0.00 1.33 449.33 24217. 0.556 0.248 0.00 1.43 449.43 26037. 0.598 0.257 0.00 1.53 449.53 27858. 0.640 0.266 0.00 1.63 449.63 29679. 0.681 0.274 0.00 1.73 449.73 31500. 0.723 0.283 0.00 1.83 449.83 33321. 0.765 0.291 0.00 1.93 449.93 35141. 0.807 0.299 0_00 2.03 450.03 36962. 0.849 0.306 0.00 2.13 450.13 38783. 0.890 0.314 0.00 2.23 450.23 40604. 0.932 0.321 0.00 2.33 450.33 42425. 0.974 0.328 0.00 2.43 450.43 44245. 1.016 0.335 0.00 2.53 45C.53 45066. 1.058 0.342 0.00 LANGLEY MEADOWS SECTION 4 107-016-006 FLOW CONTROL &WATER ' QUALITY FACILITY ANALYSIS & DESIGN � �� . _.__ Site Development Associates, LLC Staqe/Storaqe/Discharqe Performance Stage Elevation Storage Discharge Percolation (ft) (ft) (cu. ft) (ac-ft) (cfs) (cfs) 2.63 450.63 47887. 1.099 0.348 0.00 2.73 450.73 49708. 1.141 0.355 0.00 2.83 450.83 51529. 1.183 0.361 0.00 2.93 450.93 53349. 1.225 0.368 0.00 3.03 451.03 55170. 1.267 0.374 0.00 3.13 451.13 56991. 1.308 0.380 0.00 3.23 451.23 58812. 1.350 0.386 0.00 3.33 451.33 60633. 1.392 0.392 0.00 3.43 451.43 62453. 1.434 0.398 0.00 3.50 451.50 63728. 1.463 0.402 0.00 3.54 451.54 64456. 1.480 0.407 0.00 3.57 451.57 65003. 1.492 0.418 0.00 3.61 451.61 65731. 1.509 0.436 0.00 3.65 451.65 66459. 1.526 0.458 0.00 3.68 451.68 67005. 1.538 0.487 0.00 3.72 451.72 67734. 1.555 0.518 0_00 3.76 451.76 68462. 1.572 0.584 0.00 3.79 451.79 69008. 1.584 0.597 0.00 3.83 451.63 69737. 1.601 0.610 0_00 3.93 451.93 71557. 1.643 0.643 0.00 4.03 452.03 73378. 1.685 0.672 0.00 4.13 452.13 75199. 1.726 0.699 0.00 4.23 452.23 77020. 1.768 0.725 0.00 4.33 452.33 78841. 1.810 0.749 0.00 4.43 452.43 80661. 1.852 0.772 0.00 4.53 452.53 82482. 1.894 0.794 0.00 4.63 452_63 84303. 1.935 0.815 0.00 4.73 452_73 86124. 1.977 0.835 0.00 4.83 452.83 87945. 2.019 0.855 0.00 4.93 452.93 89765. 2.061 0.874 0.00 5.03 453.03 91586. 2.103 0.892 0.00 5.13 453.13 93407. 2.144 0.910 0.00 5.23 453.23 95228. 2.186 0.928 0.00 5.33 453.33 97049. 2.228 0.945 0.00 5.43 453.43 98869. 2_270 0.961 0.00 5.50 453.50 100144. 2_299 0.973 0.00 5.60 453.60 101965. 2.341 1.450 0.00 5.70 453.70 103786. 2.383 2.310 0.00 5.80 453.80 105606. 2.424 3.420 0.00 5.90 453.90 107427. 2.466 4.730 0.00 6.00 454.00 109248. 2.508 6.220 0.00 6.10 454.10 111069. 2.550 7.660 0.00 6.20 454.20 112890. 2.592 8.200 0.00 6.30 454.30 114710. 2.633 8.710 0.00 6.40 454.40 116531. 2.675 9.180 0.00 6.50 454.50 118352. 2.717 9.630 0.00 6.60 454.60 120173. 2.759 10.060 0.00 6.70 454.70 121994. 2.801 10.470 0.00 6.80 454.80 123814. 2.842 10_870 0.00 6.90 454.90 125635. 2.884 11.250 0.00 7.00 455.00 127456. 2.926 11.610 0.00 7.10 455.10 129277. 2.968 11.970 0.00 7.20 455.20 131098. 3.010 12_310 0.00 7.30 455.30 132918. 3.051 12.640 0.00 7.40 455.40 134739. 3.093 12.970 0.00 7_50 455.50 136560. 3.135 13.290 0.00 LANGLEY MEADOWS SECTION 4 107-016-006 FLOW CONTROL &WATER II QUALITY FACILITY ANALYSIS & '� DESIGN ! � �_=_ Site Development Associates, LLC Stage/Discharqe Performance at Significant Storm Events Hyd Inflow Outflow Peak Storage Stage Elev (Cu-Ft) (Ac-Ft) 1 4.36 3.90 5.84 453.84 106280. 2.440 2 2.41 0.96 5.41 453.41 96494. 2.261 3 2.91 0.89 5.02 453.02 91480. 2.100 4 2.34 0.59 3.78 451.78 68770. 1.579 5 2.47 0.54 3.74 451.74 68009. 1.561 6 2.43 0.36 2_83 450.83 51596. 1.184 7 2.84 0.29 1.81 449_81 33010. 0.758 8 1.46 0.24 1.29 449.29 23479. 0.539 Hyd R/D Facility Tributary Reservoir POC Outflow Outflow Znflow Inflow Target Calc 1 3.90 0.21 ***t**** *k**�*• 4.08 2 0.96 0.11 *******t ***x*** 1.01 3 0.89 0.14 *******' 1.10 0.94 4 0.59 0.11 '�******* *****"�* 0.61 5 0.54 0.11 ****t*** ******* 0.57 6 0.36 0.11 ******** **�**** 0.40 7 0.29 0.13 *"*****'� **�**** 0.33 8 0.24 0.07 ******** *<****+� 0.26 KCRTS Routinq Instructions Route Time Series through Facilits Inflow Time Series File:dev.tsf Outflow Time Series File:rdout.tsf POC Time Series File:dsout Znflow/Outflow Analysis Peak Inflow Discharge: 4.37 CFS at ?:00 on Jan 9 in `fear 8 Peak Outflow Discharge: 3.90 CFS a* E:OC er Jaa S in 'iear 8 Peak Reservoir Stage: 5.84 _� Peak Reservoir Elev: 453.84 Ft Peak Reservoir Storage: 106280. Cu-Ft . 2.440 Ac-Ft Add Time Series:bypass.tsf Peak Summed Discharge: 4.08 CFS a� 8:00 on .;az 9 in Year 8 Point of Compliance File:dsout.tsf Flow Duration from Time Series File:rdout.tsf C�toff Count Frequency CDF Exceedence Probabilit: CFS � � � 0.014 37420 61.024 61.024 38.976 0.390E+00 0.041 4321 7.047 68.071 31.929 0.319E+00 0.068 4628 7.547 75.618 24.382 0.244E+00 0.094 4236 6.908 82.526 17.474 0.175E+00 0.121 3078 5.020 87.546 12.454 0.125E+00 0.148 2530 4.126 91.672 8.328 0.833E-01 0.175 1563 2.549 94.220 5.780 0.578E-01 0.202 1171 1.910 96.130 3.870 0.387E-01 0.229 697 1.137 97.267 2.733 0.273E-01 0.256 514 0.838 98.105 1.895 0.189E-01 0.283 334 0.545 98.650 1.350 0.135E-01 0.310 305 0.497 99.147 0.853 0.853E-02 0.337 146 0.238 99.385 0.615 0.615E-02 0.364 128 0.209 99.594 0.406 0.406E-02 0.391 118 0.192 99.786 0.214 0.214E-02 0.418 31 0.051 99.837 0.163 0.163E-02 LANGLEY MEADOWS SECTION 4 107-016-006 FLOW CONTROL &WATER QUALITY FACILITY ANALYSIS 8� DESIGN � - - Site Development Associates, LLC 0.445 9 0.0':S 99.852 O.i48 0.148E-02 0.472 B 0.013 99.665 0.135 0.135E-02 0.499 7 0.011 99.876 0.124 0.124E-02 0.526 4 0_007 99.883 0.117 0.117E-02 0.552 2 0.003 99.886 0.114 0.114E-02 0.579 4 0.007 99.892 0.108 O.lOBE-02 0.606 4 0.007 99.899 0.101 O.101E-02 0.633 5 0.008 99.907 0.093 0.930E-03 0.660 6 0.010 99.917 0.083 0.832E-03 0.687 5 0.008 99.925 0.075 0.750E-03 0.714 3 0.005 99.930 0.070 0.701E-03 0.741 6 0.010 99_940 0.060 0.603E-03 0.768 4 0.007 99.946 0.054 0.538E-03 0.795 5 0.008 99.954 0.046 0.457E-03 0.822 6 0.010 99.964 0.036 0.359E-03 0.849 5 0.008 99.972 0_028 0.277E-03 0.876 3 0.005 99.977 0.023 0.228E-03 0.903 6 0.010 99.987 0.013 0.130E-03 0.930 3 0.005 99.992 0.008 O.B15E-04 0.957 4 0.007 99.998 0.002 G.163c-04 Flow Duration from Time Series File:dsout.tsf C�toff Count Frequency CDF Exceedence_Probability CFS � � � 0.014 37373 60.947 60.947 39.053 0.391E+00 0.042 4371 7.128 68.076 31.924 0.319E+00 0.070 4693 7.653 75.729 24.271 0.243E+00 0.099 4136 6.745 82.474 17.526 0.175E+00 0.127 3082 5.026 87.500 12.500 0.125E+00 0.155 2538 4.139 91.639 8.361 0.836E-01 0.183 1596 2.603 94_242 5.758 0.576E-01 0.211 1105 1.802 96.044 3.956 0.396E-01 0.239 735 1.199 97.242 2.758 0.276E-01 0.267 516 0.841 98.084 1.916 0.192E-01 0.295 340 0.554 98.638 1.362 0.136E-01 0.323 291 0.475 99.113 0.867 0.887E-02 0.352 155 0.253 99.366 0.634 0.634E-02 0.380 133 0.217 99.583 0.417 0.417E-02 0.408 111 0.181 99.764 0.236 0.236E-02 0.436 38 0.062 99.826 0.174 0.174E-02 0.464 10 0.016 99.842 0.158 0.158E-02 0.492 12 0.020 99.861 0.139 0.139E-02 0.520 9 0.015 99.876 0.124 0.124E-02 0.548 4 0.007 99.883 0.117 0.117E-02 0.576 3 0.005 99.687 0.113 0.113E-02 0.605 2 0.003 99.891 0.109 0.109E-02 0.633 6 0.010 99.901 0.099 0.995E-03 0.661 3 0_005 99.905 0.095 0.946E-03 0.689 6 0.010 99.915 0.085 0.848E-03 0.717 5 0.008 99.923 0.077 0.766E-03 0.745 3 0.005 99.928 0.072 0.718E-03 0.773 6 0.010 99.938 0.062 0.620E-03 0.801 4 0.007 99.945 0.055 0.554E-03 0.829 6 0.010 99.954 0.046 0.457E-03 0.857 5 0.008 99.962 0.038 0.375E-03 0.886 6 0.010 99.972 0.028 0.277E-03 0.914 3 0.005 99.977 0.023 0.228E-03 0.942 6 0.010 99.987 0.013 0.130E-03 0.970 3 0.005 99.992 0.008 O.S15E-04 0.998 3 0.005 99.997 0.003 0.325�'-04 LANGLEY MEADOWS SECTION 4 107-016-006 FLOW CONTROL&WATER QUALITY FACILITY ANALYSIS & DESIGN -. ;,,,�Iri �_ � � _ _- -----__ Site Development Associates, LLC Duration Comqarison Analysis Duration Comparison Analysis Sase File: predev.tsf New File: dsout.tsf Cutoff Units: Discharge in CFS -----Fraction of Time----- ---------Check of Tolerance------ Cutoff Base New �Change Probability Base New %Change 0.363 � O.SSE-02 O.S5E-02 0.0 � O.SSE-02 0.363 0.363 0.0 0.422 � 0.38E-02 0.19E-02 -48.3 � 0.38E-02 0.422 0.387 -8.2 0.480 � 0.25E-02 0.15E-02 -41.2 � 0.25E-02 0.480 0.406 -15.5 0.539 � 0.17E-02 0.12E-02 -26.5 ( 0.17E-02 0.539 0.453 -15.9 0.597 � 0.12E-02 0.11E-02 -5.6 I 0.12E-02 0.597 0.553 -7.3 0.656 � 0.86E-03 0.95E-03 9.4 I 0.86E-03 0.656 0.681 3.9 0.714 � 0.68E-03 0.77E-03 11.9 � 0.68E-03 0.714 0.754 5.6 0.773 � 0.49E-03 0.62E-03 26.7 � 0.49E-03 0.773 0.822 6.4 0.831 � 0.36E-03 0.46E-03 27.3 � 0.36E-03 0.831 0.858 3.3 0.890 � 0.23E-03 0.28E-03 21.4 � 0.23E-03 0.890 0.919 3.3 0.948 I 0.16E-03 0.13E-03 -20.0 I 0.16E-03 0.948 0.935 -1.3 1.01 � 0.98E-04 0.33E-04 -66.7 � 0.98E-04 1.01 0.968 -3.8 1.06 � 0.65E-04 O.00E+00 -100.0 � 0.65E-04 1.06 0.981 -7.9 1.12 � 0.16E-04 O.00E+00 -100.0 � 0.16E-04 1.12 1.01 -10.3 Maximum positive excursion = 0.066 cfs ( 8.8�) occurring at 0.749 cfs on the Base Data:p:ede�.�.tsf and at 0.815 cfs on the New Data:dsout.tsf Maximum negative excursion = 0.095 cfs (-18.551 occurring at 0.513 cfs on the Base Data:Frede:-.tsf ar_d at 0.418 cfs en the [Ie•.a Data:dsout.�sf LANGLEY MEADOWS SECTION 4 107-016-006 FLOW CONTROL&WATER QUALITY FACILITY ANALYSIS & DESIGN � _�� Site Development Associates, LLC Duration Comparison Analvsis (continued) I � . v rra�_t aur . r„o�t du' ♦ N v O R ~----__ .r�-. -- .`Y, �.M ..� +..� (n � ..,:,��♦ LL • U � ��-n�R ;i � Y,� IIf y+ d6 f uto �.',� �., N 0 � ��:, li ".� � �0 �� l ��ar:�. 0 �`�-,Y��n .,._-�'IR.. , �`��..�_ N `�::.�.R � O �� .� � __� 4�� li O �1c I O � 10 -5 10-� 10 �3 10-2 10-� 10° Probabiliiy Exceedence LANGLEY MEADOWS SECTION 4 107-016-006 FLOW CONTROL &WATER QUALITY FACILITY ANALYSIS & DESIGN i �� _� .� Site Development Associates, LLC PART`E'— WATER QUALITY SYSTEM Water quality for this project will be attained through the use of permanent wetpool storage inside the detention vault. A detail of the detention/treatment facility is included in Figure 6a of this report. Design of the water quality facility is performed as follows: Basin 1 Step 1: Identify required wetpool volume factor(f). f= 3 Per KCSWDM 6.4.1.1 Step 2: Determine rainfall(R)for the mean annual storm. R= 0.47 Per KCSWDM Fig. 6.4.1.A Step 3: Calculate runoff from the mean annual storm (V�)for the developed site. I V�= (0.9A;+0.25A� +0.10A�+ 0.01Ao)x(R/ 12) where: A; = Impervious Surface Area = 182,081 s.f. A�9 =Till Grass Area = 126,549 s.f. A� =Till Forest Area = 0 s.f. Ao = Outwash Area = 0 s.f. V�= 7,657 c.f. Step 4: Calculate required wetpool volume(Vb). Vb= fxV� Vb= 22,972 c.f. LANGLEY MEADOWS SECTION 4 107-016-006 FLOW CONTROL &WATER QUALITY FACILITY ANALYSIS & DESIGN ` � __ _ __-- Site Development Associates, LLC Basin 2 Step 1: Identify required wetpool volume factor(f). f= 3 Per KCSW DM 6.4.1.1 Step 2: Determine rainfall (R)for the mean annual storm. R= 0.47 Per KCSWDM Fig. 6.4.1.A Step 3: Calculate runoff from the mean annual storm (V,)for the developed site. V�= (0.9A;+0.25A�9 +0.10A�+0.01Ao)x(R/12) where: A; = Impervious Surface Area = 132,858 s.f. A�9=Till Grass Area = 64,490 s.f. A,� =Tiil Forest Area = 0 s.f. Ao =Outwash Area = 0 s.f. V�= 5,315 C.f. Step 4: Calculate required wetpool volume(Vb). Vb= f x V� Vb= 15,944 c.f. ; LANGLEY MEADOWS SECTION 4 107-016-006 FLOW CONTROL &WATER QUALITY FACILITY ANALYSIS & DESIGN — �;� Site Development Associates, LLC Water quality for the Bypass Area will be provided by a Biofiltration Swale. The first 50' of the swale will contain the access road and wheel strips along the swale bottom which will dictate the swale width, the swale will then taper to the minimum design width. The hydraulic residence time for the combined swa�e sections is 9.1 minutes. First 50' of swale: Step 1: Determine bypass area water quality design flows. Qwq= 0.111 cfs (See bypass area 2 yr peak from KCRTS) X 60% = 0.067 cfs Step 2: Calculate swale bottom width &flow depth. b= 4.5 ft Per KCSWDM Fig. 6.3.1.E (6'o.c. -18"of wheel strip) y= 0.08 ft Per KCSWDM Eqn. (6-3) nwq= 0.2 s= 0.015 ft/ft y= 0.17 ft max. Step 3: Determine design flow velocity. V= 0.17 fps Per KCSWDM Eqn. (6-4) Awq= 0.40 sf Step 4: Calculate swale length. _ L= 92 ft Per KCSWDM Eqn. (6-5) Step 5: Calculate residence time for first 50'. T= 50'ft r 0.17 ft1s = 4.9 min. LANGLEY MEADOWS SECTION 4 107-016-0�6 FLOW CONTROL &WATER QUALITY FACILITY ANALYSIS & DESIGN ` Site Development Associates, LLC � Last 50' of Swale: Step 1: Determine bypass area water quality design flows. Qwq= 0.111 cfs (See bypass area 2 yr peak from KCRTS} X 6Q% = 0.067 cfs � Step 2: Calculate swale bottom width &flow depth. b= 1.42 f# Per KCSWDM Eqn. (6-2) y= 0.14 ft Per KCSWDM Eqn. (6-3} nwq= 0.2 s= 0.015 ft/ft y= 0.17 ft max. Step 3: Determine design flow velocity. V= 0.20 fps Per KCSWDM Eqn. (6-4) Awq= 0.34 sf � - Step 4: Calculate swale length. L= 108 ft Per KCSWDM Eqn. (6-5) Step 5: Calculate residence time for second 50'. T= 50'ft(0.20 fils = 4.2 min. Step 6: Check conveyance capacity for 100-year flow. Q100= 0.206cfs V100= 1.15 fps < 3 fps OK n= 0.027 b= 2 ft y100= 0.08 ft A100= .18 sf LANGLEY MEADOWS SECTION 4 107-016-006 FLOW CONTROL &WATER ! QUALITY FACILITY ANALYSIS & DESIGN ' = �. s� __ ___ __ Site Development Associates, LLC APPENDIX 4-A SUPPORTING DOCUMENTS FOR HYDROLOGIC MODEL LANGLEY MEADOWS SECTION 4 107-016-006 FLOW CONTROL&WATER QUALITY FACILITY ANALYSIS & ' DESIGN i Aug 10, 2007 - 10:12AM Last Saved Dy: �rookc Shore � - - wwsor+sum�nNc �._50� �, „09:,'7»� � LANGLEY MEADOW s/sa/2oos ,o,m ,.} CITY OF RENTON, WASHINGTON "°"°°' o — ��-"� CER .� RENTON "" ^ JDZ N �� o�� , ___ ___ ___ _ o� �� DATUM planning/Building/Public Works Dept. WPHI`+� r xm ai.rw am� N0. 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Q . .. �Q rw- 12" OUTIET �� / �. . ... . . . . _, _ � �.��' o IE=448.00 '. �� W � �\ �\ Q \�� VAULT BOTTOM �y\/�/\/\/\/ � / � � � �/ j� y\/\/\ � /\ EL=447.50 // // // i/ // // � � i � a¢ } �/\ �/ �/ �/ �/' � '� \� \� \� •� \� \� \� � � a Q � � ��,� m y/�� \ j�`Q/��j��A _ o � j�////////////\/////// � o � O > � � //��VAULT FOOTING � /� /� /� � � VAULT FOOTING �� \ �\ �\ �\ `\ �\ �\ � � - �\ VAULT FODTING � Z . .N � � :j�\� /�\ DRNNG IlYP) �j/\�j/\�j�\� . � %� DRAING (iYP) �\�j\�j\�j\�j\�j\�j\�%\ - � � . \ DRPJNG (NP) J I � i O .. � �� ' /\\ / \/�\/�\ � � \/\ �\\�/\�\\�\\�\\�\\�\\� � SfORAGESEDIMEM �j `n ; W � �� , � G a %\ �� /% '� �� V��A��\�/��/V�/\ �. � � � � �A� Z �� W ... � ml� '�\�� • � BOTTOM OF DEAD \%� � /��\ BOTTOM OF DEAD , . ..:. .: • . . �.^ �\/ Q � �jJ� ~ � � N m �� / STORAGE EL=442.00 �.�� STORAGE ��/-• . . �. .�•. \ \� � �� .,. � J �J,f _ � Z� EL=a42.00 ,�/ !�;%�/�/�/�'/��/; J � � BOTfOM SLOPE 0.5�-2R �/,\/�\/�\�/, ;��. BOTTOM SLOPE O.SX-2R TOWARDS z � � �o o �s1 VAULT'A' SECTION c VAULT A' SECTION TOWARDS INLEf OF CELL our�r oF ceu Q � �U' � - - J Z � N� � v:ra v:r a u VAULT'A'SECTION ci '� o i� - s z� "' �z � � ��' � wr=3' RECOMMENDED FOR APPROVAL a ci v=i n �UI � osrosrzoo� i �o� By: Date: DATE I ;�� 3 0 3 6 J08N0. 107-016-06 1"=3' � Vertical Scale Feet By: Dote: DWGNO. �9 N I a 30 0 30 60 By: Dote: SH ET , �' Z � -30 Horizontol Scale Feet BY Date: 1 �ap �jo � L A-`,P�.__d��.ir�.x�a��,.n�e._�. ir.,�.., ea�,._�,w��r.«�.�r s�.�;.,�� r ��.�-i�. „r Ror_� �re-,�n:�,._ - s-�P _;. SECTION 3.2 RLIT�OFF C01�1PUTATIO�:'�VD:1NALYSIS T�-tETHODS FIGURE 3.2.2.A RAINFALL REG[ONS AND REGIONAL SCALE FACTORS ST 1.0/ i ST 1 0 �,q 0.8 LA 0.9 LA 1.0 LA 1.2 ST1�I � `t �� SNOHOMISN COUNT♦ '�` �� J`�ui��t.,l i.n��' _ v_ut a KiHa courvr. &- �i�� 1 ��I. -' ' __ y� 64 , �i^-c`" � .i 3 j '�� ( . � t �l� Y,�.i` ` �,4 . .--, ! :f:' k'� i j ~I, : i vi�?��• s -i� ti 'I. y-- �__ J Q • F E , �.. � 4,_,_� " / .' . �_t� iEqllo�D / -.- ( ] `' p � 1 I�PItC �� y � " O 4 ; �}^+RE ON�� ` `�—!i_ p�' # [ f } �i' �, � ,�- � 'r E'._'_I t :, ! .�a . . �-�. �� '� 1 •i ,- . .a•� i tr�i�°�d _ � � � _l � � ` . ^P �� _ �.��Arsd Ea�- , �� ! - F1Eua ��ELLE✓uE' ��°��- I F � � �y ��.. � �� EAUY 4KE - 1 I g, ; r � ":�a".p ��r �-:�'� ��„� � -�! � - ?1 t� ° �� i z�,�, -- ro� �� z � �{a� ' � -� � �'' s� .� ' � � '�i ;<«��.��E _ Le E-. � { _, �� a _ ''�"'.-.'� . • , 1 �S c Ax'�.�' oae`r `,��i._'_ �1 �'r � � 1 � �� l . � , � '_ r �.� ` �� ,� v r_:^_ S I T E °"�' , EN70 � � � _ _ �- �� ,="'-^�. I i l. �"k. �1' V � �ti: �uw h � � iu�J � - - e . o : � �- �A�� ',� �'�� s .� �I_ � a'1 r �{p�wniDT .. w 1� K[nwsrov � TA�- „ _��'., LANDSBURG , �� , � :, _., � ��. � �..�e� �e� � ��E �" �.�.� a �' 4 � �., �ti. = ( ;� ,��- ~' 4 � �� - S� �� - —�—r�--ti, --- _ . � � Fugt. �� };�..�� "_. osa�rr. " . Sci�xd Q � 'w.. "u^� ;� '�''��-'�,'� '- p .., ,�c=.� -. _,-, i �f��~ �� `�.i p 3 * .f �'` t �: r��Niur• [7-.` �i � � . " � cuu rm 4 1-1_ r ST1.1 ""� � �� %� �� - - � ' - ri� - a� `� `` = `°' 6 , ..� �`.1Kr cr�bisrr'�: r� PIEHCE CDUNTY ST 1.0 :, �.«.;� Rainfall Regions and LA 0 8/ �t + � Regional Scale Factors �A o.9 � LA1.0 LA1.2 �_-.�i Incorporated Areap �� River/Lakep Major Road� � 1/24/2005 200� Surface Water Desi�n Manual 3-22 3.22 KCRTS-RLTOFF FILES 1�1ETHOD—GE.%�'ER9 TI.�v'G TIATE SERIES TABLE 3.2.2.B EQUI�'AI:EnCE BETtiVEEN SCS SOIL TYPES AND KCRTS S�l�TY�'�S � SCS Soil Type SCS KCRTS Soil Notes Hydrologic Group Soil Group Alderwood (AgB, AgC,AgD) C Till Arents, Alderwood Material (AmB, AmC) C Till Arents, Everett Material (An) B Outwash 1 Beausite (BeC, BeD, BeF) C Till 2 Bellingham (Bh) D Till 3 Briscot (Br) D Till 3 Buckley (Bu) D Till 4 Earlmont (Ea) D Till 3 Edgewick (Ed) C Till 3 Everett (EvB, EvC, EvD, EwC) AJB Outwash 1 Indianola (InC, InA, InD) A Outwash 1 Kitsap (KpB, KpC, KpD) C Till Klaus (KsC) C Outwash 1 Neilton (NeC) A Outwash 1 Newberg (Ng) B Till 3 Nooksack (Nk) C Till 3 Norma (No) D Till 3 Orcas Or) D Wetland Oridia (Os} D Till 3 Ovall (OvC, OvD, OvF) C Till 2 Pilchuck (Pc) C Till 3 Puget (Pu D Till 3 Puyallup (Py B Till 3 Ragnar (RaC, RaD, RaC, RaE) B Outwash 1 Renton (Re) D Till 3 ; Salal (Sa) C Till 3 ' Sammamish (Sh) D Till 3 '� Seattle (Sk) D Wetland I� Shalcar (Sm) D Till 3 Si (Sn} C Till 3 i Snohomish (So, Sr) D Till 3 Sultan (Su) C Till 3 Tukwila (Tu) D Till 3 Woodinville (Wo) D Till 3 Notes: 1. Where outwash soils are saturated or underlain at shallow depth (<5 feet)by glacial till,they should be treated as till soils. 2. These are bedrock soils, but calibration of HSPF by King County DNRP shows bedrock soils to have similar hydrologic response to till soils. 3. These are alluvial soils, some of which are underlain by glacial till or have a seasonally high water table. In the absence of detailed study, these soils should be treated as till soils. 4. Buckley soils are formed on the low-permeability 09ceola mudflow. Hydrologic response is assumed to be similar to that of till soils. 200� Surface��'ater Design Manual 1/2=1;"200� 3-25 � �_� � Site Development Associates, LLC SECTION 5 CONVEYANCE SYSTEM ANALYSIS & DESIGN LANGLEY MEADOWS SECTION 5 107-016-006 CONVEYANCE SYSTEM ANALYSIS & DESIGN : � - - Site Development Associates, LLC CONVEYANCE SYSTEM ANALYSlS & DESIGN A design of the conveyance system is attached. LANGLEY MEADOWS SECTION 5 , 107-016-006 CONVEYANCE SYSTEM ANALYSIS & DESIGN i �.4 CORL- REQUIRLML'vT�4 CO�1VE1'A�CE SYSTLM 1.2.4 CORE REQUIREMENT #4: CONVEYANCE SYSTEI��1 R All engineered com-eyance system elements for proposed projects must be analyzed,designed, and E constructed to provide a minimum level of protection against overtopping, flooding, erosion, and structural u failure as specified in the following groups of requirements: i E • "Conveyance Kequirements for New Systems." Section 1.2.4.1 (belo��) M � • "Conveyance Requirements for Existing Systems," Section 1.2.4.2 (p. 1-461 N T • "Conveyance System lmplementation Requirements," Section 1.2.4.3 (p. I-47 j Intent: To ensure proper design and construction of engineered conveyance system elements. Convevance systems are natural and engineered drainage facilities that collect,contain, and provide for the flow of surface and stoi-m ��ater. This core requirement app!ic� t�:� the en��ineered elements of�on�eyancc systems—priinarily pipes, culverts, and ditcheslchannels. 1.2.4.1 CONVEI'ANCE REQUIREI�IENTS FOR NE�'4� SYSTEMS All ��eti+-conve��ance svstei�� elemenrs,30 both onsite and olfsite_ shall be analyzed, designed, and constructed aecording to [he following requirements. Also see Section 4.1 for route design and easemen[ requirements. _. ...�. --��.__---______�y ..��._ Pipe Systems ��" 1. Ne�� pipe systems shall be designed with sufficient capacity to convey and contain(at minimumj the 25-year peak flo�v; assuming developed conditions for onsite tributary areas and existing conditions for any offsite tributary areas. 2. Pipe system structures may overtop for runoff events that exceed the 25-year design capacity, provided the overflo�� from a 100-year runoff event does not create or ageravate a severeJlooding problem or severe erosion problem as described in Core Requirement#2, Section 1.2.2 (p. 1-29j. Any overflow occurring onsite for runoff events up to and including the 100-year event must i discharge ai the natural location for the project site. In residential subdivisions, this overflow must be , contained within an onsite drainage easement, tract,covenant,or public right-of-way. 3. The upstream end of a pipe system that receives runoff from an open drainage feature (pond,ditch, etc.) shall be analyzed and sized as a culvert as described below. Culverts l. New culverts shall be designed with sufficient capacin� to meet the headwater requirements in Section 4.3.1 and convey(at minimum)the 25-year peak flow, assuming developed conditions for onsite ' tributary areas and existing conditions for any offsite tributary areas. ' 2. New culverts must also convey as much of the 100-year peak flow as is necessary to preclude creating or aggravating a severe flooding problern or severe erosion problem as described in Core Requirement #2, Section 1.2.2 (p. l-29). Any overflow occurring onsite for runoff events up to and including the 100-year event must discharge at the natural location for the project site. In residential subdivisions, this overflow must be contained��ithin an onsite drainage easement, tract,covenant,or public right-of- way. 3. New culverts proposed in streams��ith salmonids shall be designed to provide for fish passage as detailed in Section 4.3.2. 1Vote: The County's critical areas regulations (KCC 21A.24)or the State Department of Fish and Wildlife may require a 6ridge to facilitate ftsh passage. _ 3o New conveyance system elements are those that are proposed to be constructed where there are no existing constructed conveyance elements. 2005 Surface 1�'ater Design Manual I/24,-2005 1-45 � , r�r�L s��s�rcn�s - �•rFTHoosor��,�;ac��s�s i Backwater Analysis Method T is method is used to analyze the capacity of both new and existing pipe systems to convey the required design flow (i.e., either the 10-year or 25-year peak flow, whichever is specified in Core Requirement #4, Section 1.2.4). ln either case, pipe system structures must be demonstrated to contain the headwater surface (hydraulic grade line) for the specified peak flow rate. Structures may overtop for the 100-year peak flo��t as allowed by Core Requirement #4. When this occurs, tl�e additional flow over the ground :urface is analyzed using the medlods for open channels described in Scction 4.4.1.2 (p. 4-61) and added to the flow ca acity of the pipe system. This method is used to compute a simple backFvater profile(hydraulic grade line) througl� a proposed or existing pipe system for the purposes of�-erifying adequate capacity. It incoiporates a re-arranged form of Manning's equation expressed in �enns uf fi-ictio��slope(slope of the energy grade line in ft/ft). The friction slope is used to determine the head loss in each pipe segment due to bairel friction, which can then be combined�vith other head losses to obtain water cwface ele�-ations at all structures along the pipe system. The back��atcr analysis begins at the do��nstream end of the pipe sy�stem and is computed back through each pipe segment and structure upstream. The fi-iction, entrance, and exit head losses computed for each pipe segment are added to tl�at segment's tailwater elevation (the water surface elevation at the pipe's outlet) to obtain its outlet control headwater elevation. This elevation is then compared with the inlet control headwater elevation,computed assuming the pipe's inlet alone is controlling capacity using the methods for inlet controi presented in Section 4.3.1.2 (p. 4-39). The condition that creates the hiehest headwater elevation determines the pipe's capacity. The approach velocity head is then subtracted from the controlling head�vater elevation,and the junction and bend head losses are added to compute the total headwater elevation, which is then used as the tailwater elevation for the upstream pipe segment. The Back�F•ater Calculation Sheet in Figure 42.].H (p.4-24) may be used to compile the head losses � and headwater elevations for each pipe segment The numbered columns on this sheet are described in Figure 4.2.1.I(p. 4-25). An example calculation is performed in Figure 4.2.1.J (p.4-26). :1%ote: This method sJaould itot be used to compule stageidischarge curves for level pool routing purposes. � Instead, a more sophistrcated backtivater analt�sis using the computer sofnvare provided with this manual is recomme�7ded as described beloia. Computer Applications The King County Backwater(KCBVV)computer program includes a subroutine B��PIPE,which may be used to quickly compute a family of backwater profiles for a given range of flows through a proposed or existing pipe system. A schematic description of the nomenclature used in this program is pro��ided in Figure 4.3.1.G (p. 4-50). Program documentation providing instructions on the use of this and the other KCBV4' subroutines is available frotn DNRP. I 2005 Surface 1�'ater Design Manual 1i24r200� 4-21 CONTRIBUTING AREAS TO EACH CATRCH BASIN estimated impervious area per lot= 3125 ft2 North Side LOT AREA ft2 ROADWAY TOTALS ft2 TOTALS acres CB Ak NO.LOTS TOTAL IMPERV PERV ft2 IMPERV PERV /MPERV PERV 12 7 45,103 14,000 31,103 8,508 22,508 31,103 0.517 0.714 11 1 6,658 1,800 4,858 1,124 2,924 4,858 0.067 0.112 10A 0 - - - - - - 0.000 0.000 10 0 - - - 2,484 2,484 - 0.057 0.000 9 4 18,942 8,000 10,942 3,882 11,882 10,942 0.273 0.251 5 0 - - - 1,350 1,350 - 0.031 0.000 6 3 13,698 6,000 7,698 4,308 10,308 7,698 0.237 0.177 7 3 17,250 6,000 11,250 3,246 9,246 11,250 0.212 0.258 8 6 28,426 12,004 16,426 5,563 17,563 16,426 0.403 0.377 13 5 20,386 10.000 10,386 5,764 15,764 10,386 0.362 0.238 Totals 29 South Side LOT AREA ft2 ROADWAY TOTALS ft2 TOTALS acres CB# LOTS TOTAL IMPERV PERV � IMPERV PERV /MPERV PERV 19 6 27,571 12,000 15,571 6,297 18,297 15,571 0.420 0.357 18 5 24,695 10,000 14,695 8,405 18,405 14,695 0.423 0.337 17 9 42,689 18,000 24,689 5,652 23,652 24,689 0.543 0.567 16 0 - - - 1,556 1,556 - 0.036 0.000 15b 0 - - - 3,023 3,023 - 0.069 0.000 15 2 14,085 4,000 10,085 2,550 6,550 10,085 0.150 0.232 14 0 - - - 6,568 6,568 - 0.151 0.000 20 1 6,331 2,000 4,331 1,818 3,818 4,331 0.088 0.099 21 0 - - - - - - 0.000 0.000 22 5 26,423 10,000 16,423 3,272 13,272 16,423 0.305 0.377 23 6 31,354 12,000 19,354 7,091 19,091 19,354 0.438 0.444 ' 24 9 83,835 18,000 65,835 9,949 27,949 65,835 0.642 1.511 Totals 43 Frontage LOT AREA ft2 ROADWAY TOTALS ft2 TOTALS acres CB# NO.LOTS TOTAL IMPERV PERV ft2 IMPERV PERV /MPERV PERV 30 0 - - - 20,000 20,000 - 0.459 0.000 29 0 - - - 3,817 3,817 - 0.088 0.000 28 0 - - - 2,710 2,710 - 0.062 0.000 27 0 - - - 5,144 5,144 - 0.118 0.000 26 0 - - - 6,252 6,252 - 0.144 0.000 Totals 0 Rainfall Table Retum Periods Durations 25 year 100 year 5 min 2.90 3.65 10 min 2.00 2.50 20 min 1.35 1.70 30 min 1.10 1.35 50 min 0.85 1.05 90 min 0.60 0.75 Rainfall Intensities are in(in/hr) Title:Langley Meadows r:\...\calcs�stortn\Im conveyance calcs-south.stm StormCAD v5.6[05.06.012.00] O6/05/07 01:18:34 f�uBentley Systems,Inc. Haestad Methods Solution Center Watertown,CT 06795 USA +1-203-755-1666 Page 1 of 1 Scenario: 100 YR i- -- . -- , -- -- — --- - - -_ _- - - ; ; �� t� o I � � o c j o I o o �' � — . � I o � o , � -=_— - � ROAD 4 �� i� _ � �i cBIi1�—�srr • ce ra�e y�'��` % � - ' I - . �� (; �I � � _ , . . . — __ '-- �' � ��fSPoi1 010 a -_ - � �. IS � _. __ —�!/ �� _ _. � i C8Y i ' ' � '- �) �,�'/�' � '� � � � f / ._.-.. ... �- _. �J � l.� I l.) G I `_ a _ _ Ll � p a l� � , _ f. ' � � � .�. __.�_ I: :�]] i ' � (1 j� i ] � tJ 3 .—_� _._� _ CB a13 ` �I ��. ce Ig; �� "�: ' I � I (1 n � I � � i � `J 'x_— �-.._ �. p= � — ' :O' Q � . i :m� t.J �� i � p i �.. ;\ � /._��t �,,:0 �% U l 'n /-� I � � .J __ F--�_I. D = I L. = �, t I V �, � ___.y I � ` `�� I I H � 31 O O O (�---�i s r�> � - I C' �c i �,;' ` � — I ; ;F I, ;� � � � i i o �i -� � �� ; r +�--- _ — ' ° � � o � ,�: - 1--- I o �, � `-' -- �� °° E �-_ �' �; � � C� i - � �. I € i — �_-- � � � � �J �� ' C� ; ; � � ' ----- �. . :—. -.�-.—_. ROAD'C --� --_ __. ' � � �__—..__ —_ - i - -_. .. .. - ..- i __—..._. . _— -�� `— � \ � ��i 11 ( ' o 0 � i f— ; � � � o 0 Title:Langley Meadows r.\...lcalcs�stortn\Im conveyance calcs-no�th.stm StormCAD v5.6[05.06.012.00] 06/05/07 01:10:25 I�Bentley Systems, Inc. Haestad Methods Solution Center Watertown,CT 06795 USA +1-203-755-1666 Page 1 of 1 Calculation Results Summa ry ----------------------------------------------------------------- ----------------------------------------------------------------- Scenario: 100 YR »» Info: Subsurface Network Rooted by: VAULT INLET »» Info: Subsurface Analysis iterations: 3 »» Info: Convergence was achieved. CALCULATION SUMMARY FOR SURFACE NETNiORKS ; Label � Inlet � Inlet j Total � Total j Capture � Gutter � Gutter � � � Type � � Intercepted � Bypassed � Efficiency � Spread � Depth � � � I � Flow � Flow � (�) � (ft} I (ft) � � � � � (cfs) � (cfs) � � � � � --------- �---------------�----------------------�-------------�---------- � ------------� --------�--------� � cs #s � Generic Inlet � Generic Default loo$ � o.lo � o.00 � loo.o � o � o.00 I CB #6 � Generic Inlet � Generic Default 100$ � 0.95 � 0.00 � 100.0 � 0 � 0.00 � I CS #7 � Generic Inlet � Generic Default 100� j 0.94 � 0.00 � 100.0 � 0 � 0.00 � � CB #8 � Generic Inlet � Generic Default 100� � 1.68 � 0.00 � 100.0 � 0 � 0.00 � � CB #9 � Generic Inlet � Generic Default 100$ � 1.13 � 0.00 � 100.0 � 0 � 0.00 � � CB #10 � Generic Inlet � Generic Default 100$ � 0.19 � 0.00 � 100.0 � 0 � 0.00 � � CB #l0A � Generic Inlet � Generic Default 100$ � 0.00 � 0.00 � 100.0 � 0 � 0.00 ! � CB #11 ! Generic Inlet � Generic Default 100$ � 0.32 � 0.00 � 100.0 � 0 � 0.00 ( I CB #12 � Generic Inlet � Generic Default 100$ � 2.37 � 0.00 � 100.0 ( 0 � 0.00 � ', CB #13 � Generic Inlet � Generic Default 100� � 1.42 � 0.00 � 100.0 I 0 � 0.00 � ------------------------------------------------------------------------------- CALCUL:vTIC2d SUh1M.�RY FOR SUBSURFF.CE NETWORK WITH RGOT: VAULT INLET � Label �i :7umber � Sectioa Sectior � Le^gth Tota'_ ', Average Hy3raulic Hydraulic � � of � Size � Shape � (ft) � System � Velocity j Grade � Grade j � � Sections � � � � Flow � (ft/s) � Upstream � Downstream � � � � � � � � (cfs) � � (ft) � (ft) � �-------� ----------�---------�----------� --------�--------� ----------�-----------�------------� ( P-77 � 1 � 18 inch � Circular � 10 � 8.01 � 4.54 � 453.98 � 453.84 � � P-76 � 1 � 18 inch � Circular � 70 � 3.28 � 1.86 , 454.14 j 453.98 � I P-99 � 1 � 12 inch � Circular � 63 � 4.95 � 6.30 � 456.86 � 453.98 � � P-75 � 1 � 18 inch � Circular � 50 � 2.51 � 1.42 � 454.21 � 454.14 � I P-98 � 1 I 12 inch � Circular I 44 � 3.96 � 5.04 � 458.14 � 456.66 � � P-74 � 1 � 18 inch � Circular � 132 � 1.68 � 3.20 � 454.28 � 454.21 � I P-103 � 1 � 12 inch � Circular � 30 � 2.63 � 8.63 � 458.66 � 458.14 � ; P-115 � 1 � 12 inch � Circular � 137 � 1.42 � 1.80 � 458.27 j 458.14 � � P-102 � 1 � 12 inch � Circular � 43 � 2.66 � 4.11 j 459.38 � 458.66 � � P-101 � 1 � 12 inch � Circular � 52 � 2.37 � 4.03 � 460.08 � 459.38 � ----------------------------------------------------------------------------------------------- Label � Total � Ground � Hydraulic � Hydraulic � � � System � Elevation � Grade � Grade � � � Flow � (ft) � Line In I Line Out � � � (cfs) � � (ft) � (ft) � � ------------- �--------� -----------�-----------�-----------� VAULT INLET � 7.99 � 460.89 I 453.84 I 453.84 I � CB #5 � 8.01 � 460.36 � 453.98 � 453.98 � � CB #6 I 3.28 � 459.41 I 454.14 � 454.14 � � CB #9 � 4.95 � 461.20 I 456.86 � 456.86 � � CB #7 � 2.51 � 458.40 � 454.21 � 454.21 ( ', CB #10 � 3.96 � 461.70 � 458.14 � 458.14 � j CB #8 � 1.68 � 456.92 � 454.28 � 454.28 I j CB #l0A � 2.63 � 461.75 � 458.66 � 458.66 � � CB #13 � 1.42 I 460.24 � 458.27 � 458.27 � � CB #11 I 2.66 � 462.42 � 459.38 � 459.38 � Title: Langley Meadows r:�...lcalcs�stormllm conveyance calcs-north.stm StormCAD v5.6[05.06.012.00] 06/05/07 01:10:37 f�Bentley Systems,Inc. Haestad Methods Solution Center Watertown.CT 06795 USA +1-2p3-755-1666 Page 1 of 2 Calculation Results Summary � CB #12 � 2.37 � 463.18 � 460.08 � 460.08 � I ------------------------------------------------------------ Completed: 06/OS/2007 01:10:29 PM Title: Langley Meadows r:\...lcalcslstormllm conveyance calcs-north.stm StormCAD v5.6[05.06.012.00] 06/05/07 01:10:37 F�vBentley Systems, Inc. Haestad Methods Solution Center Watertown,CT 06795 USA +1-203-755-1666 Page 2 of 2 Scenario: 100 YR SDA INLET ' II Label Rim Area Inlet Inlet Time dditiona Rim Hydraulic Elevation(acres) C CA of Flow Elevatio Grade {ft) (acres oncentratio (cfs) (ft) Line Out (min) (ft) CB#5 460.36 0.03 0.90 0.03 5.00 0.00 460.36 453.98 CB#6 459.41 0.41 0.62 0.26 5.00 0.00 459.41 454.14 ' CB#7 458.40 0.47 0.54 0.26 5.00 0.00 458.40 454.21 I CB#8 456.92 OJ8 0.59 0.46 5.00 0.00 456.92 454.28 �I CB#9 461.20 0.52 0.59 0.31 5.00 0.00 461.20 456.86 ! CB#10 461.70 0.06 0.90 0.05 5.00 0.00 461.70 458.14 CB#10 461.75 0.00 0.00 0.00 0.00 0.00 461.75 458.66 CB#11 462.42 0.18 0.49 0.09 5.00 0.00 462.42 459.38 CB#12 463.18 1.23 0.52 0.64 5.00 0.00 463.18 460.08 CB#13 460.24 0.60 0.64 0.39 5.00 0.00 460.24 458.27 Title: Langley Meadows r:1...lcalcslstorm\Im conveyance calcs-north.stm StormCAD v5.6[05.06.012.00] 06/05/07 01:10:56 f�Bentley Systems,Inc. Haestad Methods Solution Center Watertown,CT 06795 USA +1-203-755-1666 Page 1 of 1 ' - - � Scenario: 100 YR I� SDA PIPE Upstrea Downstream pstrea ownstrea Length onstructe Section Manning Total Fuli Node Node invert invert (ft) Slope Size n System Capacity ' Elevation Elevation (ff/ft) Flow (cfs) (ft) (ft) (cfs) i CB#6 CB#5 451.23 448.20 70 0.043226 18 inch 0.020 3.28 14.19 � CB#7 CB#6 451.71 451.23 50 0.009728 18 inc 0.020 2.51 6.73 � CB#5 VAULT INL 447.70 447.00 10 0.070316 18 inc 0.020 8.01 18.10 CB#8 CB#7 453.04 451.71 132 0.010035 18 inc 0.020 1.68 6.84 CB#9 CB#5 452.77 448.20 63 0.072523 12 inc 0.020 4.95 6.24 CB#11 CB#10A 458.61 457.96 43 0.015009 12 in 0.020 2.66 2.84 �I , CB#12 CB#11 459.38 458.61 52 0.014864 '12 inc 0.020 2.37 2.82 'I CB#10 CB#10 457.96 454.89 30 0.102397 12 inc 0.020 2.63 7.41 CB#10 CB#9 454.89 452.77 44 0.048250 12 inch 0.020 3.96 5.09 I CB#13 CB#10 455.64 452.89 137 0.020051 12 inch 0.010 1.42 6.56 I Title: Langley Meadows r:1...\calcslstormllm conveyance calcs-northstm StormCAD v5.6[05.06.012.00] 06/05/07 01:1�:03 f�vBentley Systems, Inc. Haestad Methods Solution Center Watertown,CT 06795 USA +1-203-755-1666 Page 1 of 1 Profile Scenario: 100 YR � Profile: CB12 to Vauit Scenario: 100 YR � Label: CB #12 Rim: 463.18 ft Invert Out Elevation: 459.38 ft � r Label: CB #� 1 �, � Rim: 462.42 ft Invert Out Elevation: 458.61 ft � Label: CB #10A Rim: 461.75 ft � Invert Out Elevation: 457.96 ft ; Label: CB #�0 Rim: 46�.70 ft �. 43 ft Invert Out Elevation: 454.89 ft S�Ze: 12 � r Label: CB #9 __ -_- S�3' Sp09 �ft '__-- __ ---_i� Rim: 461.20 ft __ 465.00 � Invert Out Elevation: 452.77 ft I � ' ' ' _ - -- - 460.00 <; ' . 44 Label: VAULT INLET ' �� 52 ft �,\ Rim: 460.89 ft SiZe: �482SO � I y2 i S� ��486��ft �'0��O- - T� �\°�� - 455.00 ��v�;7� Elevation (ft) �� , - - ------ _�_ ._S S,� �` _ ,, __ 450.00 ' • ��0.'',6�, � Label: CB #5 '�j �� ,�F` Rim: 460.36 ft ' `�5�3�,h � lnvert Out Elevation: 447.70 ft � -- _ � S. .c, <. _- � � OO�o.j y ' 445.00 O ' �� y �� _ -____--__ � 440.00 0+00 �+00 2+00 3+00 Station (ft) Title: Langley Meadows r:\...1calcslstormUm conveyance calcs-north.stm StormCAD v5.6[05.06.012.00] O6/05/07 01:11:16 f�v8entley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 1 Profile Scenario: 100 YR Profile: CB 8 to Vault Scenario: 100 YR ;- Label: CB #8 Rim: 456.92 ft Invert Out Elevation: 453.04 ft �r Label: CB #7 ; Rim: 458.40 ft ; Invert Out Elevation: 45� .71 ft -- - --- __ --, � ._ ____� Label:_CB #6 _ 465.00 � Rim: 459.41 ft Invert Out Elevation: 451 .23 ft � � �� ----- ---------- _ ---__-, -- --- - , . _--- =--_ _ � 460.00 l __ _ ,\ Label: VAULT INLET , '� Rim: 460.89 ft ; ... - ___ \ , _ `4i2'e; . >g _ , -_ ' 455.00 � �— 432��h ', 6F� Elevation (ft) L: 132 ft � Siz�:-�g �nc� _ _ _ _ _ ,�'`,_ 450.00 S: 0.070035 ftjft �= 50 ft 1'- Label: CB #5 ' S�Ze� 78 �nch Rim: 460.36 ft , S� 0-009728 �ft ' , Invert Out Elevation: 447.70 ft � --- —__ -- _____L�.-Si � _ , _ � _.. _ _ ' 445.00 � O �o. ' y � •�� jcPp 1� ; ' O • ' �'y��,h ' - __-- _ _ ___ _ �'� 440.00 0+00 1+00 2+00 3+00 Station (ft) Title: Langley Meadows r:\...lcalcs�storm\Im conveyance calcs-north.stm StormCAD v5.6[05.06.012.00] 06/05J07 0�:11:24 f�vBentley Systems, Inc. Haestad Methods Solution Center Watertown,CT 06795 USA +�-203-755-1666 Page 1 of 1 Profile Scenario: 100 YR Profile : CB 13 to CB 10 Scena rio: 100 YR ;� Label: CB #13 ;�� Rim: 460.24 ft r, �' Invert Out Elevation: 455.64 ft 465.00 �- Label: CB #10 / ,� Rim: 461 .70 ft Invert Out Elevation: 454.89 ft , - - 460.00 Elevation (ft) — 455.00 S L' �3� �t S: p e' 72 i h .020�5 7 � , ft -- 450.00 0+00 1 +00 2+00 Station (ft) Title: Langley Meadows r:\...\calcs�.stormUm conveyance calcs-north.stm StormCAD v5.6[05.06.012.00] 06/05J07 01:11:30 f�8entley Systems, Inc. Haestad Methods Solution Center Watertown,CT 06795 USA +1-203-755-1666 Page 1 of 1 Scenario: 25 YR I � � _-- — �--�---— -i---T — �__ � �, I o � �, � �, o � � `�' ' I ' - � � � � ; ;. ; � ' i i -___-_ ._. ROA7A' \�` _ i � . _ � ; � \ � -- T ` , ,, � - , ; . .- -- _ ___ ; , _. ;. , � _ � , �� --- -� � C O � • �'— �__ �' � � �. t — = — I c �.' , L7 ; i _ p O = ; � G O l --- -- .�--._— __ ;: —� � '' = C �' �a __ _ II'i — r` I pl� J `. � . O' y" _'_—_ � � � � �7 i� •�1 -. (� ��> .� > f! �� , _ ....---- CB�9 �) \ CBYb � j L� --�� . �-� �j � C ,.,I . 4' s � il � � � �� Cl i �: - �.- ^: � .�' �' L• g� d: . . tie ii (-1 _ � . _ �J i� � °� ---- � �-. i � I `� t� - ��CQ CB s �-� I � � �� ----- I 'n , . �_� � -� �1� ': � � N � � I � _� ! f� 1 _Q � ' ``_I CY } ' .__-i ; ; i � r`? ce�fi il al i ; —T f - -g "I � � � ��'`I Ce �_) v u� ir�i�r z 1�I ce r - +, _ -- - Q z°; LZs __ m c xiv,.L�_ Q� �Vis' C� oao c o '� -----�_ Calculation Results Summary ----------------------------------------------------------------- ----------------------------------------------------------------- Scenario: 25 YR »» Info: Subsurface Network Rooted by: VAULT INLET 2 »» Info: Subsurface Analysis iterations: 4 »» Info: Convergence was achieved. CALCULATION SUMMARY FOR SURFACE NETWORKS � Label � Inlet � Inlet � Total � Total � Capture � Gutter � Gutter � ( � Type � � Intercepted � Bypassed � Efficiency � Spread � Depth � � � � � Flow � Flow � (�) � (ft) � (ft) � � � � � (cfs) � (cfs) � � � � �---------� ---------------�----------------------� -------------�----------�------------�--------�--------� � CB #14 � Generic Inlet � Generic Default 100� � 0.40 � 0.00 � 100.0 � 0 � 0.00 � , � CB #15 � Generic Inlet � Generic Default 100� � 0.56 j 0.00 � 100.0 � 0 � 0.00 � � CB #16 � Generic Inlet � Generic Default 100� � 0.09 � 0.00 � 100.0 � 0 � 0.00 � � cB #15A � Generic Inlet � Generic Default l00$ � o.00 � o.00 � 100.0 � o � o.00 � � CB #15B � Generic Inlet � Generic Default 100� � 0.18 � 0.00 � 100.0 � 0 � 0.00 � � CB #20 j Generic Inlet � Generic Default 100� � 0.30 � 0.00 � 100.0 � 0 � 0.00 � � CB #21 � Generic Inlet � Generic Default 100� � 0.0o � �.00 ( 100.0 � 0 � 0.00 � ' � cE #2z � Generic Inlet � Generic Default loo� � l.os � o.00 f loo.o � o � o.00 � � CB #17 ( Generic Inlet � Generic Default 100� � 1.84 � 0.00 � 100.0 � 0 � 0.00 � � CB #18 � Generic Inlet � Generic Default 100� � 1.36 � 0.00 � 100.0 � 0 � 0.00 � � CB #19 � Generic Inlet � Generic Default 100� � 1.37 � 0.00 � 100.0 � 0 � 0.00 � � CB #23 � Generic Inlet � Generic Default 100� � 1.48 ( 0.00 � 100.0 � 0 � 0.00 � � CB #24 � Generic Inlet � Generic Default 100� � 2.79 � 0_00 � 100.0 � 0 � 0.00 � CALCULATION SUMMARY FOR SUBSURFACE NETWORK WITH ROOT: VAULT INLET 2 � Label � Number � Section � Section � Length � Total j Average � Hydraulic � Hydraulic � � � of � Size � Shape � (ft) � System � Velocity � Grade � Grade � � � Sections � ( � � Flow � (ft/s) � Upstream � Downstream � � � � � � � (cfs) � � (ft) � (ft) � �-------�----------�---------�----------�--------�--------�----------� -----------�------------� � P-118 � 1 � 18 inch � Circular � 16 � 6.46 � 3.65 � 453.55 � 453.41 � � P-117 � 1 � 18 inch � Circular � 93 � 3.15 � 1.78 � 453.75 � 453.55 � � P-126 � 1 � 18 inch � Circular � 149 � 4.98 � 2.82 � 454.35 � 453.55 � � P-116 � 1 � 18 inch � Circular � 38 � 3.11 � 1.76 � 453.83 � 453.75 � ( P-120 � 1 � 12 inch � Circular � 29 � 0.12 � 0.15 � 453.75 � 453.75 � � P-125 � 1 � 18 inch � Circular � 38 � 4.79 � 2.71 � 454.53 � 454.35 � � P-115 � 1 � 18 inch � Circular � 51 � 3.10 � 1.75 � 453.94 � 453.83 � � P-119 � 1 � 12 inch � Circular � 91 � 0.18 � 0.23 � 453.76 � 453.75 � � P-124 � 1 � 18 inch � Circular � 56 � 4.91 � 2.78 � 454.82 � 454.53 � � P-114 � 1 � 18 inch � Circular � 83 � 2.00 � 1.13 � 454.01 � 453.94 � � P-123 � 1 � 18 inch � Circular � 78 � 4.07 � 2.30 � 455.10 � 454.82 I � P-113 � 1 � 18 inch � Circular � 200 � 1.37 � 0.77 � 454.09 � 454.01 � � P-122 � 1 � 18 inch � Circular � 169 � 2.79 � 3.67 I 455.37 � 455.10 � ----------------------------------------------------------------------------------------------- � Label � Total � Ground � Hydraulic � Hydraulic � � ( System � Elevation � Grade � Grade � � � Flow � (ft) � Line In � Line Out � � � (cfs) � � (ft} � (ft) � � ---------------�-------- �-----------�-----------�-----------� I VAULT INLET 2 I 6.44 I 457.13 I 453.41 � 453.41 � � CB #14 � 6.46 � 456.67 � 453.55 � 453.55 � ' � CB #15 � 3.15 � 455.67 � 453.75 � 453.75 � � CB #20 � 4.98 � 458.26 � 454.35 � 454.35 � ' Title: Langley Meadows r:\...lcalcs\storm\Im conveyance calcs-south.stm StormCAD v5.6[05.06.012.0o] 06/05/07 01:12:03 I�Bentley Systems, Inc. Haestad Methods Solution Center Watertown,CT 06795 USA +1-203-755-1666 Page 1 of 2 Caiculation Results Summary � CB #16 f 3.11 � 454.48 � 453.83 � 453.83 � � CB #15A � 0.12 � 455.67 � 453.75 ( 453.75 � � CB #21 � 4.79 � 457.00 � 454.53 � 454.53 � � CB #17 � 3_10 � 454.14 � 453.94 � 453.94 � � CB #15B � 0.18 � 454.70 � 453.76 � 453.76 � � CB #22 � 4.91 � 456.53 � 454.82 � 454.82 � I CB #18 � 2.00 � 454.57 � 454.01 � 454.01 � I CB #23 � 4.07 I 457.09 � 455.10 � 455.10 � � CB #19 � 1.37 � 455.78 � 454.09 � 454.09 � � CB #z4 � 2.79 � 458.60 � 455.37 � 455.37 � -------------------------------------------------------------- ----------------------------------------------------------------- I ----------------------------------------------------------------- Completed: 06/OS/2007 01:11:58 PM ', Title: Langley Meadows r:\...lcalcslstorm\Im conveyance calcs-south.stm StormCAD v5.6(05.06.012.00] 06/05/07 01:12:03 f�Bentley Systems, Inc. Haestad Methods Solution Center Watertown,CT 06795 USA +�-203-755-1666 Page 2 of 2 Scenario: 25 YR SDA INLET Label Rim Area Inlet Inlet Time dditiona Rim Hydraulic Elevatio (acres) C CA of Flow Elevation Grade (ft) (acres oncentratio (cfs) (ft) Line Out (min) (ft) CB#14 456.67 0.15 0.90 0.14 5.00 0.00 456.67 453.55 CB#15 455.67 0.38 0.51 0.19 5.00 �.00 455.67 453.75 CB#16 454.48 0.04 0.90 0.03 5.00 0.00 454.48 453.83 CB#15 455.67 0.00 0.00 0.00 0.00 0.00 455.67 453.75 CB#15 454.70 0.07 0.90 0.06 5.00 0.00 454.70 453.76 CB#20 458.26 0.19 0.56 0.10 5.00 0.00 458.26 454.35 CB#21 457.00 0.00 0.00 0.00 0.00 0.00 457.00 454.53 CB#22 456.53 0.68 0.54 0.37 5.00 0.00 456.53 454.82 CB#17 454.14 1.11 0.57 0.63 5.00 0.00 454.14 453.94 CB#18 454.57 0.76 0.61 0.46 . 5.00 0.00 454.57 454.01 CB#19 455.78 0.78 0.60 0.47 5.00 0.00 455.78 454.09 CB#23 457.09 0.88 0.57 0.51 5.00 0.00 457.09 455.10 CB#24 458.60 2.15 0.44 0.96 5.00 0.00 458.60 455.37 Title:Langley Meadows I r:\...\calcs�storm\Im conveyance calcs-south.stm StormCAD v5.6[05.06.012.00] 06/05/07 01:12:10 f�uBentley Systems,Inc. Haestad Methods Solution Center Watertown,CT 06795 USA +1-203-755-1666 Page 1 of 1 Scenario: 25 YR SDA PIPE Upstrea Downstream pstrea ownstrea Length onstructe Sec6on Manning Total Full Node Node Invert Invert (ft) Slope Size n System Capaary Elevation Elevation (ft/ft) Flow (cfs) (ft) (ft) (cfs) CB#15 CB#14 449.11 447.25 93 0.020000 18 in 0.020 3.15 9.66 CB#16 CB#15 450.35 449.61 38 0.019474 18 inc 0.020 3.11 9.53 CB#14 VAULT INLE 447.75 447.00 16 0.046875 18 in 0.020 6.46 14.78 CB#15 CB#15A 451.70 450.79 91 0.010000 12 inch 0.020 0.18 2.32 CB#15 CB#15 450.29 450.11 29 0.006207 12 in 0.020 0.12 1.82 CB#20 CB#14 450.73 447.75 149 0.020000 18 inch 0.020 4.98 9.66 CB#21 CB#20 451.10 450.73 38 0.009737 18 inch 0.020 4.79 6.74 CB#22 CB#21 451.65 451.10 56 0.009821 18 inch 0.020 4.91 6.77 CB#19 CB#18 452.50 451.30 200 0.006000 18 inch 0.020 1.37 5.29 CB#18 CB#17 451.30 450.86 83 0.005301 18 inch 0.020 2.00 4.97 CB#17 CB#16 450.86 450.35 51 0.010000 18 inch 0.020 3.10 6.83 CB#23 CB#22 452.43 451.65 78 0.010000 18 inch 0.020 4.07 6.83 CB#24 CB#23 454.12 452.43 169 0.010000 18 inch 0.020 2.79 6.83 Title: Langley Meadows r.\...1calcslstormUm conveyance calcs-southstm StormCAD v5.6[05.06.012.00] li 06/05/07 01:12:16 I�Bentley Systems, Inc. Haestad Methods Solution Center WateRown,CT 06795 USA +1-203-755-1666 Page 1 of 1 �� Profile Scenario: 25 YR Profile: CB19 to Vault Scenario: 25 YR �- Label: CB#18 i Rim:454.57 ft I nvert Out Elevation:451.30 ft Label:CB#17 Rim:454.14 ft r Label:CB#19 Invert Out Elevation:450.86 ft, Rim:455.78 ft �Label:CB#16 Invert Out Elevation:452.50 ft Rim:454.48 ft Invert Out Elevation:450.35 ft Label:CB#15 . �Rim:455.67 ft �__ _----- ------- ----_ _ _-- ----T----- -- IrnertOuYElevation:449.91 f460.00 ` L:83 ft ' ' Label:VAULT WLET 2 Size: 18 inch ': Rim:457.13 ft ' S:0.005301 fUft , � . ' - � -- ---- _ -- _ . _ .--- _ _ ! 455.00 Si2e�9g h \ Elevation(ft) ' L:200 ft S' �•02000p�h �` Size: 18 inch . . . �,, 450.00 S:0.0060!DO fUft �'S1 ft ' L Label:CB#14 , Srze: 1g ineh ��38 ft Rim:456.67 ft , S:0.010000 ft/ft S,S�2e� lg�� ; Invert Out Elevation:447J5 ft ' ��19474�ft -s� �• - ' 445.00 . . _ __ : -- —_— _ 0+00 1+00 2+00 3+00 _ _ 4+00 s�p2e��ss�5+00 �468�5�h �� Station(ft) Title: Langley Meadows r:1...\calcs\stormllm conveyance calcs-south.stm StormCAD v5.6[05.06.012.00] 06/05/07 01:14:37 f�v8entley Systems.Inc. Haestad Methods Solution Center Watertown,CT 06795 USA +1-203-755-1666 Page 1 of 1 Profile Scenario: 25 YR j Profile: CB24 to Vault Scenario: 25 YR Label:CB#23 Rim:457.09 ft InveR�ut Elevation:452.43 ft �Label:CB#22 Rim:456.53 ft I I Invert Out Elevation:451.65 ft Label:CB#14 � Label:CB#21 Rim:456.67 ft �Label:CB#24 � �Rim:457.00 ft �Invert Out Elevation:447.75 ft I Rim:458.60 ft � Invert Out Elevation:451.10 ft I , Invert Out Elevation:454.12 ft� - Label:CB#20 1 i Rim:458.26 ft. . - � I Invert Out Elevation:450.73 4 f___ _ __--.. --- I�I � L. 7 _ I _ - _ ; ; R m457 13 ft INLET 2 �i - Size• 8 ft r I __ __.__ � ___ __ __ _---_ - +, 455.00 � L: 169 ft '' S:0�O20ppp�� Elevation(ft) ' Size: 18 inch 1t/f� :—_S__D.0-�-000�ft1ft -__ —---- _ __ — _ __ _ 450.00 � L:56 ft . L:38 ft s� �. ; Size• 18 rnch S¢e: 18 inch S�2e� �6 ' S:0.009821 ft/ft S: � 0.009737�/ft �468)�h _ . __ __ __—._ _— - - __ __ _ — --- _ ___ ___S 445.00 0+00 1+00 2+00 3+00 4+00 5+00 ��' 6+00 Station(ft) Title: Langley Meadows r:\...lcalcslstorm\Im conveyance calcs-south.stm StormCAD v5.6[05.06.012.00] 06/05/07 01:15:23 I�vBentley Systems, Inc. Haestad Methods Solution Center Watertown,CT 06795 USA +1-203-755-1666 Page 1 of 1 Profile Scenario: 25 YR Profile : CB 15B to CB 15 Scenario: 25 YR ,�- Label: CB #15B i Rim: 454.70 ft ;' Invert Out Elevation: 451 .70 ft � � � Label: CB #15A , -- - -- -----_ __ _ ;' Rim: 455.67 ft 4 � Invert Out Elevation: ��f��9 ft , I I I i � I ; � I I � I I - -- 455.00 � � Label: CB #15 Rim: 455.67 ft Elevation (ft) Invert Out Elevation: 449.11 ft _-- L: 9-� ft - L: 29 ft 450.00 Size: �2 in�h Size: 12 inch S� �.010000 {�ft S: 0.006207 ft/ft _ _ 445.00 0+00 1 +00 2+00 Station (ft) II TiUe:Langley Meadows r:\...\calcs�stormllm conveyance calcs-south.stm StormCAD v5.6[05.06.012.00] O6/05/07 01:15:40 f�uBentley Systems, Inc. Haestad Methods Solution Center Watertown,CT 06795 USA +1-203-755-1666 Page 1 of 1 Calculation Results Summary ----------------------------------------------------------------- ----------------------------------------------------------------- Scenario: 100 YR »» Info: Subsurface Network Rooted by: VAULT INLET 2 »» Info: Subsurface Analysis iterations: 3 »» Info: Convergence was achieved. CALCULATION SUMMARY FOR SURFACE NETWORKS � Label ; Inlet � Inlet � Total � Total � Capture � Gutter � Gutter � � � Type � � Intercepted � Bypassed � Efficiency j Spread � Depth � � � � � Flow � Flow � ($} I (ft) � (ft) � � � � � (cfs) � (cfs) � � i � �------- � --------------� ---------------------� ----�----------� ------------�--------�- -� � CB #14 � Generic Inlet � Generic Default 100% � 0.50 ( 0.00 I 100.0 � 0 � 0.00 � � CB #15 � Generic Inlet � Generic Default 100% I 0.71 � 0.00 � 100.0 � 0 � 0.00 � � CB #16 � Generic Inlet � Generic Default 100� ' 0.12 � 0.00 � 100.0 � 0 ( 0.00 � � CB #15A � Generic Inlet � Generic Default 100% i 0.00 � 0.00 � 10�.0 � 0 � 0.00 � � CB #15B � Generic Inlet � Generic Default 100g � 0.23 � 0.00 � 100.0 � 0 � 0.00 � � CB #20 � Generic Inlet � Generic Default 100g � 0.38 � 0.00 � 100.0 � 0 � 0.00 � � CB #21 � Generic Inlet � Generic Default 100% � 0.00 � 0.00 � 100.0 � 0 I 0.00 � � CB #22 � Generic Inlet ( Generic Default 100� � 1.36 � 0.00 � 100.0 � 0 � 0.00 � � CB #17 � Generic Inlet � Generic Default 100� � 2.32 � 0.00 � 100.0 � 0 � 0.00 � � CB #18 � Generic Inlet � Generic Default 100� � 1.71 � 0•00 � 100.0 � 0 � 0.00 � � CB #19 � Generic Inlet � Generic Default 100% � 1.72 ! 0.00 � 100.0 � 0 � 0.00 � � CB #23 � Generic Inlet � Generic Default 100% � 1.86 � o.OD � 100.0 � 0 � 0.00 I � CB #24 � Generic Inlet ( Generic Default 100% � 3.52 � 0.00 � 100.0 ( 0 � 0.00 � CALCULATION SUMMARY FOR SUBSURFACE NETWORK WITH ROOT: VAULT INLET 2 � Label � Number � Section � Section � Length I Total j Average � Hydraulic � Hydraulic � � � of � Size � Shape � (ft) � System � Velocity � Grade ( Grade � � � Sections � � � � Flow � (ft/s) � Upstream � Downstream � � � � � � � (cfs) � � (ft) � !ft) � �-------� ---------- �---------�----------�--------�--------� ----------�-----------�------------� � P-118 � 1 � 18 inch � Circular � 16 ( 8.83 � 5.00 � 454.11 I 453.84 I � P-117 � 1 I 18 inch I Circular � 93 I 4.27 I 2.41 � 454.47 I 454.11 � � P-126 � 1 � 18 inch � Circular � 149 � 6.06 � 3.43 � 455.28 � 454.11 � I P-116 � 1 � 18 inch � Circular � 38 j 4.13 I 2.34 � 454.61 I 454.47 � � P-120 � 1 � 12 inCh � Circular � 29 � 0.16 � 0.20 � 454.47 � 454.47 � � P-125 � 1 � 18 inch � Circular I 38 � 5.81 � 3.29 � 455.56 ( 455.28 � � P-115 � 1 � 18 inch � Circular � 51 � 4.18 � 2.36 � 454.67 � 454.48 � � P-119 � 1 � 12 inch � Circular j 91 � 0.23 � 0.29 � 454.48 � 454.47 � � P-124 � 1 � 18 inch � Circular ; 56 � 5.93 ( 3.36 � 455.98 � 455.56 � I P-114 � 1 I 18 inch I Circular � 83 � 2.69 � 1.52 I 454.27 � 454.14 � � P-123 � 1 � 18 inch � Circular � 78 � 4.89 � 2.77 � 456.38 � 455.98 � � P-113 � 1 � 18 inch I CirCular � 200 � 1.72 � 0.97 � 454.40 ! 454.27 I � P-122 � 1 I 18 inch � Circular � 169 � 3.52 � 1.99 � 456.83 � 456.38 � � Label � Total � Ground � Hydraulic � Hydraulic � � � System � Elevation � Grade � Grade � � � Flow � (ft) � Line In � Line Out � � � (cfs) � � (ft) � (ft) � �---------------�-------- �-----------�-----------i-----------� � ( VAULT INLET 2 � 8.82 � 457.13 � 453.84 � 453.84 � I �i ��-�� CB #14 � 8.83 � 456.67 � 454.11 � 454.11 � � � CB #15 I 4.27 I 455.67 I 454.47 I 454.47 I , � CB #20 I 6.06 I� 458.26 I 455.28 � 455.28 � � Title:Langley Meadows I r.\.._lcalcs\storm\Im conveyance calcs-southstm 5tormCAD v5.6[05.06.012.00] � ,I 06/05/07 01:16:27 f�Bentley Systems, Inc. Haestad Methods Solution Center Watertown,CT 06795 USA +�-203-755-1666 Page 1 of 2 Calculation Results Summary I CB #16 � 4.13 � 454.48 I 454.48 � 454.48 � I CB #15A � 0.16 � 455.67 � 454.47 I 454.47 � � CB #21 � 5.61 � 457.00 � 455.56 � 455.56 � � CB #17 I 4.18 � 454.14 � 454.14 � 454.14 � � CB #15B � 0.23 � 454.70 � 454.48 � 454.48 � � CB #22 � 5.93 I 456.53 I 455.98 � 455.98 � � CB #18 � 2.69 � 454.57 � 454.27 I 454.27 � � CB #23 � 4.89 � 457.09 � 456.38 I 456.38 � � CB #19 � 1.72 � 455.78 � 454.40 � 454.40 � � CB #24 � 3.52 � 458.60 � 456.83 � 456.83 � ------------------------------------------------------- Completed: C6/O5/2007 01:15:21 PM Title: Langley Meadows r:\...\calcslstormllm conveyance calcs-south.stm StormCAD v5.6[05.06.012.00) 06/05/07 01:16:27 f�Bentley Systems, Inc. Haestad Methods Solution Center Watertown,CT 06795 USA +�-203-755-1666 Page 2 of 2 Scenario: 100 YR SDA INLET Label Rim Area Inlet Inlet Time dditiona Rim Hydraulic Elevatio (acres C CA of Flow Elevatio Grade (ft) (acres oncentratio (cfs) (ft) Line Out (min) (ft) CB#14 456.67 0.15 0.90 0.14 5.00 0.00 456.67 454.11 CB#15 455.67 0.38 0.51 0.19 5.00 0.00 455.67 454.47 CB#16 454.48 0.04 0.90 0.03 5.00 0.00 454.48 454.48 CB#15 455.67 0.00 0.00 0.00 0.00 0.00 455.67 454.47 CB#15 454.70 0.07 0.90 0.06 5.00 0.00 454.70 454.48 CB#20 458.26 0.19 0.56 0.10 5.00 0.00 458.26 455.28 CB#21 457.00 0.00 0.00 0.00 0.00 0.00 457.00 455.56 CB#22 456.53 0.68 0.54 0.37 5.00 0.00 456.53 455.98 CB#17 454.14 1.11 0.57 0.63 5.00 0.00 454.14 454.14 CB#18 454.57 0.76 0.61 0.46 5.00 0.00 454.57 454.27 CB#19 455.78 0.78 0.60 0.47 5.00 0.00 455.78 454.40 CB#23 457.09 0.88 0.57 0.51 5.00 0.00 457.09 456.38 CB#24 458.60 2.15 0.44 0.96 5.00 0.00 458.60 456.83 Title: Langley Meadows r:�...\calcslstorm\Im conveyance calcs-south.stm StormCAD v5.6[05.06.012.00] 06/05/07 01:16:34 f�Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 1 Scenario: 100 YR SDA PIPE Upstrea Downstream pstrea ownstrea Length onstructe Section Manning Total Full Node Node Invert Invert (ft) Slope Size n System Capacity Elevation Elevation (fUft) Flow (cfs) (ft) (ft) (cfs) CB#15 CB#14 449.11 447.25 93 0.020000 18 inch 0.020 4.27 9.66 CB#16 CB#15 450.35 449.61 38 0.019474 1 S inch 0.020 4.13 9.53 CB#14 VAULT INLE 447.75 447.00 16 0.046875 18 inch 0.020 8.83 14.78 CB#15 CB#15A 451.70 450.79 91 0.010000 12 inc 0.020 0.23 2.32 CB#15 CB#15 450.29 450.11 29 0.006207 12 in 0.020 0.16 1.82 CB#20 CB#14 450.73 447.75 149 0.020000 18 inch 0.020 6.06 9.66 CB#21 CB#20 451.10 450.73 38 0.009737 18 inch 0.020 5.81 6.74 CB#22 CB#21 451.65 451.10 56 0.009821 18 inch 0.020 5.93 6.77 CB#19 CB#18 452.50 451.30 200 0.006000 18 inc 0.020 1.72 5.29 CB#18 CB#17 451.30 450.86 83 0.005301 18 inc 0.020 2.69 4.97 CB#17 CB#16 450.86 450.35 51 0.010000 18 in 0.020 4.18 6.83 CB#23 CB#22 452.43 451.65 78 0.010000 18 inch 0.020 4.89 6.83 ' CB#24 CB#23 454.12 452.43 169 0.010000 18 inch 0.020 3.52 6.83 i , �1 � . _� . ' � � I ) � Title: Langley Meadows . r:\...\calcslstorm\Im conveyance caics-south.stm StormCAD v5.6[05.06.012.00] 06/05/07 01:16:39 f�JBentley Systems,Inc. Haestad Methods Solution Center Watertown,CT 06795 USA +1-203-755-1666 Page 1 of 1 Profile Scenario: 100 YR Profile: CB19 to Vault Scenario: 100 YR Label:CB#18 Rim:454.57 ft Invert Out Elevation:451.30 ft Label:CB#17 ` Rim:454.14 ft � Invert Out Elevation:450.86 ft Label:CB#19 Label:CB#16 Rim:455J8 ft Rim:454.48 ft Invert Out Elevation:452.50 ft Invert Out Elevation:450.35 ft Label:CB#15 � Rim:455.67 ft - --__ ---_ _ ------- .....___. --- . _-- -- -__. ._---- ---_ ___ rt Out Etevation:449.11 f160.00 L:83 ft � Label:VAULT INLET 2 ' Size 18 inch Rim:457.13 ft , ! S:0.005301 ft/ft � ' __ '- _ - _ __ _ ___ —.._._ _— 455.00 SF2e.�93 ft Elevation(ft) _ S�Q.020 p�� `� L:200 ft __ ``•� 450.00 — .._ _ __ . __ -- Size: 18 inch — S:0.006000 ft/ft L:5 ft `�Label:CB#14 '" SS0.010000�ft S, L��g J�� Rim:456.67 ft S�2e� Invert Out Elevation:447.75 ft ' _ ___ _ _ _ ___ . _ _ _ _ ��7�74 ft/f� _ S�-f.�r __ 445.00 _ ___ p+pp 1+pp 2+00 3+00 4+00 S'p2e�r 6� 5+00 - •a�68��h �� Station(ft) Title:�Langley Meadows r:1...lcalcslstorm\Im conveyance calcs-south.stm StormCAD v5.6[05.06.012.00j 06/05l07 01:�6:49 F�Bentley Systems, Inc. Haestad Methods Solution Center Watertown,CT 06795 USA +1-203-755-1666 Page 1 of 1 Profile Scenario: 100 YR I Profile: CB24 to Vault Scenario: 100 YR Label:CB#23 rRim:457.09 ft I Invert Out Elevation:452.43 ft ' � ,- Label:CB#22 - I I Rim:456.53 ft j Invert Out Elevation:451.65 ft �Label:CB#14 I Label:CB#21 � Rim•456.67 ft ,-Label:CB#24 � r Rim:457.00 ft ;� Invert Out Elevation:447J5 ft . r ;' Rim:458.60 ft � I I Invert Out Elevation:451.10 ft � ; Invert Out Elevation:454.12 ftl ��:CB#20 ' � � I � Rim:458.26 ft ; � % � Invert Out Elevation:450 73 fy� . --- — -__—�- ---..�_____ t_ _-- _ -—i------- 460.00 -- � Label:VAULT INLET 2 _ _ _ � _ ___ I _ _ i' , _ _ _ _ ___ ; ', Rim:457.13 ft � ��U:010000� ; 455.00 _..— - -- — _- --- — __ ___ L� 149 S��e� � Elevation(ft) L: 169 ft S�O.D2p00pc� � Size' 18 inch ____��D.O�Up00 fG'ft __ _----- - __ __ __ __ __ _.. 450.00 L'S6 ft L:38 ft S S?�•'� Size� 18 inch Size: 18 inch '�0 r8� S:0.009821 ft/fi� S:0.009737 ft/ft .__ ' g68�s��h— 445.00 -_ _- ---._.... ----- ---__ - __ ___---- 0+00 1+00 2+00 3+00 4+00 5+00 �� 6+00 Station(ft) Title: Langley Meadows r:1...lcalcslstorm\Im conveyance calcs-south.stm StormCAD v5.6[05.06.012.00] 06/05/07 01:16:56 F�Sentley Systems, Inc. Haestad Methods Solution Center Watertown,CT 06795 USA +1-203-755-1666 Page 1 of 1 Profi le Scenario: 100 YR � Profile : CB 15B to CB 15 Scenario: 100 YR � � Labei: CB #15B � Rim: 454.70 ft ,' Invert Out Elevation: 451 .70 ft � �� Label: CB #15A ; i ___ '; Rim: 455.67 ft _--- ___ 4��9 ft ' Invert Out Elevation: � � i � � , � I I _ . _ ,. . ._ ,. -- �\ -- 455.00 , � Label: CB #15 Rim: 455.67 ft Elevation (ft) Invert Out Elevation: 449.11 ft ____ �� 9.1 ft _ �: 29 ft 450.00 S�Ze� �2 inch Size: 12 inch s� 0.010000 ft/ft S: 0.006207 ft/ft _- 445.00 0+00 1 +00 2+00 Station (ft) Title:Langley Meadows r:\...lcalcs\storm\Im conveyance calcs-south.stm StormCAD v5.6[05.06.012.00] 06/05l07 01:17:04 F�Bentley Systems. Inc. Haestad Methods Solution Center Watertown,CT 06795 USA +�-203-755-1666 Page 1 of 1 Scenario: 100 YR � INLET ;a7 ,Yy�B s30 I — t I '1 � � � � i v � � � �'' �.� � � C� � ; � _1__ I Q 129 i - � - - � : I �' ._ . ROA�'A' L__ /� % '— �j �� ,— �\ � Ci '� . —-- � _ _ / ; � . — . � � _ , , , , __ _ ._� . a i��'' (�� O _ O � - .za = � i � i �� =� � � �) iJ � � � , -+=— — , a � _. � �. � � � � � � I � �. �. _, : � r D: _ 127 'o= ^ __ i m; � �..i - I . � ' - u a `1 :� � i ' O _ . D � i ,a _ _ . -- .� � � ` i J ,I . � 'll �� ( �� ° � � �: , ` : C� �J � i� �I ; � E O �t � �' � O ,� � �i e rzs ''-----•i � t € q J I� I' _ i; a �: � OUTLET . L� � � ' � �� o ' o � p - 'o Q <� I � � � O �� E — ' ; �_ � Q Q � � J ; f---� - --� �? -- _ ��,_.—_ -- � ROPD'C � : �i---� .. -- \� � I � � V I ' 1 I �' � i �.,� �J � I / -- � —- � \ i ' I Title:Langley Meadows r:\...\stormUm conveyance calcs-frontage.stm StormCAD v5.6[05.06.012.00] 06/05J07 01:17:24 f�.Bentley Systems, Inc. Haestad Methods Solution Center Watertown,CT 06795 USA +1-203-755-1666 Page 1 of 1 _ _ Calculation Results Summary , Scenario: 100 YR »» Info: Subsurface Network Rooted by: OUTLET »» Info: Subsurface Analysis iterations: 3 »» Info: Convergence was achieved. CALCULATION SUMMARY FOR SURFACE NETWORKS � Label � Inlet j Inlet � Total ; Total � Capture � Gutter � Gutter � � � Type � � Intercepted � Bypassed � Efficiency � Spread � Depth � � � � Flow � Flow I (�) � (ft) � (ft) � � � � � (cfs) � (cfs) � � � � � --------�--------------�---------------------� ------------�----------�------------�-------� --------� I CB #z6 � Generic Inlet � Generic Default 100$ � 0.48 � 0.00 � 100.0 � 0 � 0.00 � � CB #27 � Generic Inlet � Generic Default 100$ � 0.39 � 0.00 � 100.0 � 0 � 0.00 � � CB #26 � Generic Inlet � Generic Default 100$ � 0.21 � �.00 � 100.0 � 0 � 0.00 � � CB #29 � Generic Inlet � Generic Default 100$ � 0.30 � 0.00 � 100.0 � 0 � 0.00 � � CB #30 � Generic Inlet � Generic Default 100$ � • 0.00 � 0.00 � 100.0 � 0 � 0.00 � � iNLET � Generic Inlet � Generic Default lOGF � 1.16 � 0.00 � 1CC.0 I 0 � 0.00 � �I -------------------------------------------------------------------------------------- CALCL'LATION SUMMARY FOR SliBSURFACE NETWORK WiTH ROOT: OUTi_,ET � Label � Number � Section � Section � Length � Total � Average � Hydraulic � Hydraulic � � � of � Size � Shape � (ft) � System � Velocity � Grade � Grade � � � Sections � � � � Flow ( (ft/s) � Upstream � Downstream � � � � � � � (cfs) � � (ft) � (ft) � � �----------�---------�----------�-------- �-------�---------- �---------�------------� � P-64 � 1 � 12 inch � Circular I 17 � 1.90 � 2.59 � 461.93 � 461.66 � , � P-63 � 1 � 12 inch � Circular � 210 � 1.72 � 2.60 � 463.22 � 461.93 � , � P-62 � 1 � 12 inch � Circular � 174 � 1.51 � 2.56 � 464.18 � 463.22 � I � P-61 � 1 � 12 inch � Circular � 92 � 1.38 � 2.52 � 464.69 � 464.18 � il � P-60 � 1 � 12 inch � Circular � 118 � 1.16 � 2.43 � 465.32 � 464.69 � �i � P-59 I 1 � 12 inch � Circular � 15 � 1.16 � 7.60 � 467.23 � 465.32 � I ----------------- --------------------------------------------------------------------------- I, Label � Total � Ground � Hydraulic � Hydraulic � I� � System � Elevation � Grade � Grade � � Flow I (ft) I Line In � Line Out � � (cfs) � � (ft) � (ft) � --------� --------� -----------�-----------�-----------� OUTLET � 1.89 � 463.35 � 461.07 � 461.07 � ' CB #26 � 1.90 � 463.35 � 461.93 I 461.93 � CB #27 � 1.72 � 465.03 � 463.22 � 463.22 � ; CB #28 � 1.51 � 466.43 � 464.18 � 464.18 � ; CB #29 � 1.38 � 467.09 � 464.69 � 464.69 � ' CB #30 � 1.16 � 468.12 � 465.32 � 465.32 � j INL�'T , 1.15 � 470.00 � a67.23 � 467.23 I Cc;npleted: 06/05;2007 O1 17:28 PM.________________________________ I! Title: Langley Meadows r:\...lstorm\Im conveyance calcs-frontage.stm StormCAD v5.6[05.06.012.00] 06105l07 01:17:32 f�t/Bentley Systems, Inc. Haestad Methods Solution Center Watertown,CT 06795 USA +1-203-755-1666 Page 1 of 1 > Scenario: 100 YR , SDA INLET Label Rim Area Inlet Inlet Time dditiona Rim Hydraulic Elevation(acres) C CA of Flow Elevation Grade (ft) (acres oncentratio (cfs) (ft) Line Out (min) (ft) CB#2 463.35 0.14 0.90 0.13 0.00 0.00 463.35 461.93 � CB#2 465.03 0.12 0.90 0.11 5.00 0.00 465.03 463.22 CB#2 466.43 0.06 0.90 0.06 5.00 0.00 466.43 464.18 CB#2 467.09 0.09 0.90 0.08 5.00 0.00 467.09 464.69 -- CB#3 468.12 0.00 0.00 0.00 0.00 0.00 468.12 465.32 INLET 470.00 0.35 0.90 0.32 5.00 0.00 470.00 467.23 � � � Title: Langley Meadows r:1...lstormllm conveyance calcs-frontage.stm StormCAD v5.6(05.06.012.00] 06/05/07 01:17:39 f�Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA +�-203-755-1666 Page 1 of 1 Scenario: 100 YR SDA PIPE Upstrea ownstrea psVea ownstrea Length onstructe Section Manning Total Full Node Node Invert Invert (ft) Slope Size n System Capacity Elevation Elevation (ft/ft) Flow (cfs) (ft) (ft) (cfs) CB#27 CB#26 462.43 461.17 210 0.005995 12 inch 0.020 1.72 1.79 CB#26 OUTLET 461.17 461.07 17 0.006061 12 inc 0.020 1.90 1.80 INLET CB#30 466.78 464.74 15 0.136138 12 inc 0.020 1.16 8.54 CB#30 CB#29 464.74 464.03 118 0.006020 12 inc 0.020 1.16 1.80 CB#29 CB#28 464.03 463.48 92 0.006004 12 inc 0.020 1.38 1.79 CB#28 CB#27 463.48 462.43 174 0.005995 12 inc 0.020 1.51 1.79 �� I (� . Title: Lan le Meadows I 9 Y r:\...\stormllm conveyance calcs-frontage.stm StormCAD v5.6[05.06.012.00] O6/05/07 01:17:51 F�Bentley Systems, Inc. Haestad Methods Solution Center Watertown,CT 06795 USA +�-203-755-1666 Page 1 of 1 Profile Scenario: 100 YR �-� •�n # � �- R t AY,�. . . . . . •! iTf :SF .Y. . . � . . .. . . 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Haestad Methods Solution Center Watertown,CT 06795 USA +1-203-755-1666 Page 1 of 1 __ .._. Site Development Associates, LLC _ - ._ SECTION 6 SPECIAL REPORTS & STUDIES LANGLEY MEADOWS SECTION 6 107-016-006 SPECIAL REPORTS & STUDIES � Site Development Associates, LLC SPECIAL REPORTS & STUDIES None of the special reports and studies listed in Section 2.3.1.1 of the KCSWDM have been prepared for this project. ; � _. � � < , �- � i '��, � ; ,, . ;. �, �_ , � ' i ' � LANGLEY MEADOWS SECTION 6 107-016-006 SPECIAL REPORTS & STUDIES _ __ I � � .. Site Development Associates, LLC -� � , . \ , SECTION 7 � OTH ER PERM ITS LANGLEY MEADOWS SECTION 7 107-016-006 OTHER PERMITS Site Development Associates, LLC OTHER PERMITS - This project will require a clearing and grading permit from King County, and building permits will need to be obtained prior to home construction on the individual lots. No additional permits from other agencies are required. LANGLEY MEADOWS SECTION 7 107-016-006 OTHER PERMITS � = �;� ------ -- —_ _ Site Development Associates, LLC SECTION 8 CSWPPP ANALYSIS & DESIGN LANGLEY MEADOWS SECTION 8 107-016-006 CSWPPP ANALYSIS & DESIGN � �` . , ___ -- ._ Site Development Associates, LLC CSWPPP ANALYSlS & DESlGN This section of the report, along with the Temporary Erosion and Sediment Control (TESC) Plan included in the engineering drawings, is intended to serve as the construction Stormwater Pollution Prevention Plan (SWPPP)for the project. The SWPPP is outlined in conformance with the 2001 edition of the Washington State Department of Ecology's Stormwater Manaqement Manual for Western Washinqton (DOE Manual). STEPS 1&2— DATA COLLECTION&ANALYSIS The topography of the site has been described previously in this report as being gently sloping toward the east. No significant slopes currently exist on the project site, and none are expected to be created. The topography of the site is shown in the engineering planset, as well as in Figure 5 of this report. Soils on the project site have been identified previously in this report as being of the Alderwood variety, which is generally considered to be a till soil, with moderate to high runoff potential and little capacity for infiltration. The existing ground cover at the project site consists of a handful of single-family residences and associated driveways, surrounded by landscaping and lawn area. A critical wetland area lies immediately to the east of the project site. This wetland area appears to have been recently enhanced by the construction of the nearby Shamrock subdivision. Proper erosion and sediment control practices shall be implemented to ensure that the construction of Langley Meadows does not affect the adjacent wetland area. STEP 3 —CONSTRUCTION SWPPP DEVELOPMENT AND IMPLEMENTATION -- The development and implementation of this SWPPP shall consist of 12 specific elements, as outlined in the DOE Manual. They are: 9. Mark Clearing Limits Clearing limits will be flagged or fenced by the contractor or project surveyor prior to commencement of construction activity. 2. Establish Construction Access A stabilized rock construction entrance will be installed at the entrance to the plat at the onset of construction. LANGLEY MEADOWS SECTION 8 107-016-006 CSWPPP ANALYSIS & DESIGN I�� _ � � ' __ __ _ ; Site Development Associates, LLC j _____ _ __ � 3. Defain Flows Prior to significant clearing, the permanent detention facility shall be constructed, ' so that it can be used for temporary sediment control. A temporary sediment riser shall be installed in order to ensure proper sediment control. Once the facility is constructed, the site shall be cleared and graded, and all surface water , controls shall direct runoff to this facility. When final grading is complete and the site is stabilized, the temporary sediment riser shall be replaced with a permanent flow control structure. 4. Install Sediment Controls Filter fabric fencing (silt fence) shall be installed around the downstream perimeter of the site in order to keep sediment-laden stormwater from leaving the site. The fencing shall be inspected periodically to ensure its continued effectiveness. 5. Stabilize Soils The temporary erosion and sediment control plan calls for the stabilization of exposed soils through mulching or hydroseeding when the soils are not to be worked for a significant period of time. The plan also calls for the establishment of permanent vegetation through hydroseeding once the site has reached final grade. 6. Protect S/opes The project does not propose the creation of any significant slopes. 7. Protect Drafn Inlets The temporary erosion and sediment control plan calls for a filter fabric sock to be installed at all nearby catch basin inlets. Filter fabric protection shall be placed in all new catch basins as they are installed. 8. Sfabilize Channels and Ouflets All temporary interceptor swales shall contain check dams whenever a drop of 2 vertical feet occurs. Water discharged from the sedimentation facility shall outfall onto a rip-rap splash pad. LANGLEY MEADOWS SECTION 8 107-016-006 CSWPPP ANALYSIS & DESIGN Site Development Associates, LLC 9. Control Po!lutants All waste materials shall be disposed of in an approved location, in accordance with City of Renton standards. In order to reasonably prevent a contamination event (such as a fuel spill), all major vehicle maintenance shall occur off-site to the greatest extent practicable. The contractor shall provide a vehicle staging area near the entrance to the site where all fueling and maintenance activity is likely to take place. This is intended to contain the area in which a contamination event is likely to take place. The contractor shall immediately contain and clean- up an area in which a contamination event occurs. 10. Control Dewatering No significant dewatering is expected to occur during this project. 91. Maintain BMPs All BMPs should be monitored and maintained regularly to ensure adequate operation. A TESC supervisor shall be identified at the beginning of the project to provide monitoring and direct the appropriate maintenance activity. As site conditions change, all BMPs shall be updated as necessary to maintain compliance with County standards. 92. Manage the Project The project will begin with a pre-construction conference in which an on-site TESC supervisor shall be identified. The on-site supervisor shall monitor all TESC facilities regularly and maintain a log of inspections and improvements to demonstrate compliance with City standards. The project is not large enough to be effectively phased, therefore, it will be important that the entire site is in conformance with City of Renton erosion control standards at all times. The TESC supervisor shall notify Site Development Associates of any problems with the proposed erosion control elements, or if any revisions to the plan need to be made. Additional erosion control materials, such as filter fabric fencing, cover plastic, and straw bales, shall be kept on-site at all times in the event that an erosion control feature needs to be replaced or installed. LANGLEY MEADOWS SECTION 8 107-016-006 CSWPPP ANALYSIS & DESIGN Site Development Associates, LLC _� c � ,�� ' � , � � � .� � , SECTION 9 FACILITY SUMMARIES AND COVENANTS i , LANGLEY MEADOWS SECTION 9 107-016-006 BOND QUANTITIES, FACILITY SUMMARIES, AND COVENANTS � _ _ Site Development Associates, LLC Facility Summarv The following page of this document contains a reduction of the storm detention facility plan. This is intended to summarize the stormwater detention and treatment functions of the proposed development. Declaration of Covenant The project does not create any new off-site storm drainage features that will be owned or maintained by the City, so no declaration of covenant is needed. } �� LANGLEY MEADOWS SECTION 9 107-016-006 BOND QUANTITIES, FACILITY SUMMARIES, AND COVENANTS KING COUNTY, WASHINGTOV, SURFACE �VATER DESIGN MANUAL STORMWATER FACILITY SUMMARY SHEET Development Lan le Meadows Date 06/06/07 Location Renton WA ENGINEER DEVELOPER Name Scott Mesic Name Lan le Develo ment Grou Firm Site Develo ment Associates, LLC Firm Address 10117 Main Street Address Bothell, WA 98011 Phone 425-486-6533 Phone Developed Site: Acres 12.04 Number of lots 74 Number of detention facilities on site: 1 Number of infiltration facilities on site: ponds ponds X vaults vaults tanks tanks Flow control provided in regional facility(give location) NA No flow control required NA Exemption number Downstream Draina e Basins Immediate Ma'or Basin Basin A Cedar River Basin B Basin C Basin D Number& type of water quality facilities on site: biofiltration swale (regular/wetl or sand filter(basic or large?) continuous inflow?) sand filter, linear(basic or large?) combined detention/WQ pond sand filter vault(basic or large?) (WQ portion basic or large?) X combined detention/wetvault stormwater wetland compost filter wetpond (basic or large?) filter strip wetvault flow dispersion farm management plan landscape management plan oiUwater separator(baffle or coalescing plate?) catch basin inserts: Manufacturer pre-settling pond 1998 Surface Water Design Manual 9/1/98 1 KING COUNTY, VI'ASHIVGTON, SURFACE WATER DES[GN MANL'AL pre-settling structure: Manufacturer flow-splitter catchbasin DESIGN INFORMATION INDIVIDUAL BASIN A B C D Water Quality desi flow Water Quality treated volume or 16,320 cf 23,040 wetpond Vr I 9/1/98 1998 Surface W'ater Design Manual ?_ � � KING COUNTY, VVASHINGTON, SURFACE WATER DESIGN MANUAL DESIGN TOTAL INDNIDUAL BASIN INFORMATION, cont'd Drainage basin(s) A B C D Onsite area 12.39 ac Offsite area NA Type of Storage Vault i Facilit Live Stora e Volume 100,144 cf Predeveloped Runoff 2-year 0.728 cfs Rate 10-year l.l l cfs 100-year 1.95 cfs Develo ed runoff rate 2-year 0.40 cfs 10-year 0.94 cfs 100-year 4.08 cfs T e of restrictor Riser Size of No. 1 2.81" orifice/restriction No. 2 3.50" No. 3 No. 4 FLOW CONTROL & WATER QUALITY FACILITY SUMMARY SHEET SKETCH I All detention, infiltration and water quality facilities must include a sketch per the following criteria: 1. Heading for the drawings should be located at the top of the sketch (top right-hand corner). The heading should contain: • North arrow (point up or to left) • D9# • Plat name or short plat number • Address (nearest) • Date drawn(or updated) • Thomas Brothers page, grid number 2. Label CBs and MHs with the plan and profile designation. Label the control structure in writing or abbreviate with C.S. Indicate which structures provide spill control. 3. Pipes-- indicate: Pipe size Pipe length Flow direction Use s single heavyweight line 4. Tanks-- use a double, heavyweight line and indicate size (diameter) 5. Access roads • Outline the limits of the road • Fill the outline with dots if the road is gravel. Label in writing if another surface. 6. Other Standard Symbols: 1998 Surface Water Design Manual 9�1/98 Z KING COUNTY, WASHINGTON, SURFACE ��'ATER DESIGN MANUAL • Bollards: • • • • ■ ■ ■ ■ • Rip rap o00000 000000 Fences --x---x---x---x---x---x--- • Ditches -�-�--�-��---�-C D 7. Label trash racks in writing. 8. Label all streets with the actual street sign designation. If you don't know the actual street name, consult the plat map. 9. Include easements and lot lines or tract limits when possible. 10. Arrange all the labeling or writing to read from left to right or from bottom to top «�ith reference to a properly oriented heading. 11. Indicate driveways or features that may impact access, maintenance or replacement. 9/1/98 1998 Surface Water Design Manual d � PORTION OF TFE NW V4, SE U4, SEC. 1p, TWP 23 N, RGE 5 E, WM o i ' � N � - . �S � : ...�....................: :.........................: :............ ........: :.........................: :.............. ..-..:.... ...... ......... .... ..... ............ . .. .. ............ .. �o a ' � ............ ... .. . . ... .... ........................... ........................... ....................... _�� G \ � V . . . . : : : : � gpF !■ : . ;.•• � . � _ ' ... " 0 [ � ! .........: :... .. . - .,� � .. 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Q ■' . i _ _ _ . .� �:e N L- � a � 3 i � ' N_ � m � '� LL 3 : �� i Q° q� � SEE STRUCTURAL PJNS FOR � � m I ° � �� VAULT CONSTRUCTION DETAll.S � °1 �� a � � � � f ' � �; LID ELEVATION �!, � �� 456t '�� m � A �� AIANHOLE FRAME AND � _ X � \ � LOCKING '�a � _ Z ��q COVER !� _ � w Sl � � BOTfOM LJD ELEVATION 45a.50 � OVERFLOW WSE 453.64- ' RISER ELEVATION 453.50 � �.��: � � U J U � Z 2 :, 3 3 �ELBOW RESTRICTOR z i ELEVATION 451.50 a g MANHOLE STEPS � a � � � 8 I 3" x 0.90 GAUGE REMOVABLE � O Q � I SUPPORT BRACKEiS � WATERTIGHT 3�' MANHOLE RISER __�. �� 3'-0" CTRS. MIN. FL4NGENG OR W/ RING AND � , �-3'. Q SHEAR GATE W O � � � ^ � CONTROL ROD FOR HOLLOW CORE VAULT LID � � . Q � w CLEANOUT/ DRAIN SEE STRUCTURAL PLANS Q Z Z ' �P a (BEND R0� AS REQ. FOR 6' Q �� 0 18' CMP CRO55 W � w J FLOW RESTRICTOR VERTICAI ALIGNMENT W/ COVER) � � � I '�n STAND PIPE. i a � . v�i� m � Q . � _ _ 48" MANHOLE LID W � W I � ' i 12" WLE7 12" OUTLET I i � Q � ELEVATION 446.00 � EIEVATION 448.00 �_ � J w � � 6" MA% v ° �!Q � z VAULT ACCESS DETAIL Z � O �; m. - mi� `� ALUM. RESTRICTOR PL4TE N'T'S' Q ' W F-- �� PRIMARY ORIFICE Z J Z � Z�n ELEVATION 446.00 3-1/2" DIA. ORIFICE CUT � F W v I o z IN 12 GA PtATE & � z � �' �_� o f ALUM. RESTRICTOR PUTE WELDED TO ELBOW. z � �� 1D WRH ROUND CLEAN 3D O 30 60 Q Z W �� 1"=30' � J � � � r¢ 2-13/76' DIA ORIFICE - � ✓�r � ELBOW RESTRICTOR DETAIL SCaIE Feet w � � ' z rn CUT IN 12 G0. PLATE & z w n I c�i o WELDED TO ALUTA. CMP x "-' _ n � o c�, CRoss. RECOMMENDED FOR APPROVAL � v �n � ��'j TYPE 2-54' CATCH BASIN g�,: ppte: DATE �/�/�� o I�4 SECTION JOB NO. 107-01&O6 o By: Dote: i � CONTROL STRUCTURE DETAIL � DWG NO. ��B � � N.7.S By: Date: o SHEET �N� o � Z By: Date: ')/��F �O -7' R�.\Pr.. �t=� ,-, ito`��.rlF fi5 ilnr�l.. M.<r..nws...N.. .� t�.. �r.�l f�..�.��t� nl R>.,_n'�,II.'-rIl' rn.. - .�rn.F .,. o PORTION OF TFE NW V4, SE V4, SEC. 1p, TWP 23 rl, RGE 5 E, WM � �' "N a � N b U � F a � O � � � ��^ m � J m OI J Z N = p Z O (n 652.00' v O a J � � � U Q � w i Ss.00' o z w 0 U O � O N 80TTOM OF UD Z � �.�' ACCESSG ttP) �=454.50 I y I� Z �O Z FINISHED GRADE 457-460 'Q�'v=i J �/�\/ _ . _ . _ . . • / .. • \ ' - - � \\�\\� g � `o �Q Q. \�� _ _ MAX WSE 453.84' _ - MAX WSE 453.84 _ � _ �/�� `O' ?i /�\ e6' FREEBOMD � 6' FREEBOARD �—� � � � �\ � w � �/\ _ _ - - - \��\ � ° Jz � ��\ _ o - - o - - - �� , � - w �� j/ � � r 4'z4' OPENING � //�\ � Q� O j�\\ � � w LL�E _ � - TTM jUGH WALL _ \//�\_. J - o � �\ _ 1D - � . �O 12� OUTLET � \%� � � � - � IE=448.00 \�� w /�� • _ � N � 6� SEDIMENT YAUIT BOTfOM EL=447.50 � � /'� �- � � � STORAGE . r . : . . . • . • ' � �'��: w _ � - - � � � � � � � � � � � �� / � � � � � � �� /,: � ie=aai oo - o � ' - VA�VA�VA%VA�VA%�A��A��,�V��\�V�iV��'V��i��V��V��V��V �;%>. - //�//�//�//��/i /�,//;�;//��/��j\�j\�j��/\�/� : /�� - � - - /�\�/\\�/�\�\ � VAULT'A' SECTION \\/`\��\\��\\��\\��\\��\f � \� a /� � - - . /�/�/. �/�/�/�/�� , %� VAULT FOOTING � � ��\� � � . �\��\� - H:f-30' �\��\\�j\\�j\\�/V._1 . �..\//��DRAING �NP) U Q O Qo //�\ - STORAGESEDIMENT _ �\\\�� V:T=3' �\��\��\�� ' . \�/�� m > i 3 .�� . �(��i m o 3 E " �� . . BOTfOM OF DEAO /�\�/�\�/� 's ... . — _' .-:—. . __�__ _.._ �'�t�// :J , m Y U� \ BO ARDSS NLEf\OF CELz \\\\//\\\\\\\/ BOTTOM SLOPE 0.5�4x TOWARDS42.00 \��\\�\\jj\�j\�j/\��'\\�7�\�\\��\\/\\��\j�\��\\//\j\\j/\\�j��//\ . : N_� � o 9 . OUTLEf OF CELL �� /\ / ' � /, . :..\�\i��.� '�. � m' .0 �' � � � c °' Q� y 9I C a a a I`c ;' > ' N- � m s 272.00' -LL � � I �� o� g-- `u �g � � 192.00' � � � ��p � '��.. �.��o��. . f �7� F ` . � 64.00' �'�. N'=��.� ¢ 20.00' , 79.00' 20.00' � / v�� > ` o I m g S'x1O' GRAT O i �y�� 'I �! ACCESS (ttP) � ^ �"r�� i BOTfOM OF LID � BOTTON OF LID BOTTOM OF UD �, w c�� FINISHED GRPDE 457-460 EL=454.50 FINISHED GRADE 457-460 I EL=454.50 EL=454.50 FINISHED GRADE 45�-460 i o � ' �'�%;�/��j��j �j� � /��j��j��j� �� . , ��\ %�j � � � � � � � / `i � � � � � � \jjj�/ ,\/\/\/\ /\/�\/�\ �j �� /� /� /� //�� \ - - �� ,. 'j\//�\//�\/ $_M_AX � 4�8�j\ \�j\�j\�j WV( WSE 453.84%\�j�� j - IA�AX WSE 453.64 � • 6'FREEBOARD M�-� WSE 453.84 �j/.. � o � � \/\/\ /\/ //�//� �/�\//� �\.'. ' _ ` ; U '' cW+ ' s a \\�j\\�j\\� /\\�\ �'x4' OPENING /�\/� %i;;�, 6" FREEBOARD - _ . ,. Z � 3 3 ��\� �. �\ THROUGH WALL � \/��/� \\� •� 4'z4' OPENING � `�..��( �� — '��///� ' //� j\//� : ///\ \/i� ' � _ TMP�ucH wui � _ w�E � � Z � �� 1 � � ��\, • �\ �\, \��' j\ ' o _ o _ � � o p /\ - �� 6• SEDIMENT � \/�\ io _ i� _ O � F- _= a SiORAGE � � 3�' a 18" INLET � 18" INLEf //� - u? - IE=447.0 Q � W a o W . IE=447.00 \�� . \ IE=447.00 i\� - STORAGE ENT ..._ . . _... . . . — — -- � Z � � N \� o �E-44�� j� � e� W �� . . ' .. . . .. .: ..� �- ___ __.W ' ...... � .._ ___ �1� W � - � \� \�� cv �/� VAULT BOTTOM �/�/�/�/�/�/ � U �} / �� o .. � . �- ��\ 4a /� EL=447.50 // �j �j �j �j �j a5 � / : �Q m �� '\ ��\��\��\ � �` �� \� \� \� \� \� \� o �, � a Q ��, /\�3' � � �`cz �\ �\ N '�/,/�-- � /�\/�\/�\/�\/�\/�\/ . `^ } O > .// � '�/ �/ �/ � ��\�\�\�\�\�\�\ � \'� � u � I �j\\ /�\ DRAING (�P)G i\\j\\j\\� � � j� YAULT FOOTING �/j/j/j�/j/j/%/j � iS a �/ VAULT FOOTING J ; O �� DRAING (NP) � � � � � � � � � � / DRNNG (lYP) � . !�\� � �\�j\�j\ �o \�j\ %\��\��\��\��\��\��\�� . '0 6" MIN. SEDIMENT �\� W � ° I�� a ��\ -.// \\//�� , . ' �/�� ///\//\\�/�\�/��/��/�\ � � S70RAGE\ �. \/� Z } W 'o m�. \ /� ' i/ B0170M OF DEAD �/� /�/i BOTTOM OF DEAD . .: � ' �' • • .\/ w � m �m. `� .A; STOR4GE ELa442.00 '.��/.';� STORAGE ��. ' � � V�� V � � -� �J,J a �o- EL�442.00 ,A� �/�� /��/ � Z BOTfOM SLOPE O.SS-2R �/,\�/\��\�%�;,�/� � � p z Z BOTTOM SLOPE O.SX-2x TOWARDS z �, �o o �s� VAULT'A'SEC110N �� VAULT'A'SECTION rowaaos INLEf OF CELL OUnEf OF CELL Q � - �c~i � - �t r�a - K r�a o � , �� v r� v:r=a� e VAULT'A'3ECTION w � J � � �v� Yr�' RECOMMENDED FOR APPROVAL a ci r=n � �o� � V,� By: Date: DATE ��7 in;" 1 _3. 3 0 3 6 �oe No. w�-o�s oe - By: Date: Vertical Scate Feet OWGNO. ��9 30 0 30 60 By Dote: H ET _ ,..=3°� Y 15�F 20 I `�'^ � Honzontal Scale Feet B: Date: - .=,.P�� i,�i��•.��..'. _ � . � �,i��. .�,1�� . �.�. r., -. , -._ . .- , . -� „ . �i-. c.�, - , _P *n r � _, ¢ ' Site Development Associates, LLC SECTION 10 � OPERATIONS & MAINTENANCE MANUAL , LANGLEY MEADOWS SECTION 10 107-016-006 OPERATIONS & MAINTENANCE MANUAL . �_ � `� Site Development Associates, LLC OPERAT101YS 8 MA/NTENANCE MANUAL The following pages have been selected from the current King County Stormwater Management Manual, and shall serve as the operations and maintenance manual for the project. LANGLEY MEADOWS SECTION 10 107-016-006 OPERATIONS & MAINTENANCE MANUAL � ' '�s �} Site Development Associates, LLC � NO. 3 -CLOSED DETENTION SYSTEMS (PIPES/TANKS) Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed Storage Area Plugged Air Vents One-half of the cross section of a vent is blocked at Vents free of debris and any point with debris and sediment sediment Debris and Accumulated sediment depth exceeds 10%of the All sediment and debris Sediment diameter of the storage area for Y�length of storage removed from storage area. vault or any point depth exceeds 15%of diameter. Example:72-inch storage tank would require Geaning when sediment reaches depth of 7 inches for more than Yz length of tank. Joints Between Any crack allowing material to be transported into All joint between tank/pipe Tank/Pipe Section facility sections are sealed Tank Pipe Bent Out Any part of tank/pipe is bent out of shape more than Tank/pipe repaired or replaced of Shape 10°/o of iYs design shape to design. Manhole Cover Not in Place Cover is missing or only partially in place.Any open Manhole is closed. manhole requires maintenance. Locking Mechanism cannot be opened by one maintenance Mechanism opens with proper Mechanism Not person with proper tools.Bolts into frame have less tools. ' Working than Y=inch of thread(may not apply to self-locking lids.) , Cover Difficult to One maintenance person cannot remove lid after Cover can be removed and Remove applying 801bs of lift. Intent is to keep cover from reinstalled by one maintenance sealing off access to maintenance. person. Ladder Rungs King County Safety Office and/or maintenance person Ladder meets design standards Unsafe judges that ladder is unsafe due to missing rungs, allows maintenance person safe misalignment,rust,or cradcs. access. � Catch Basins See"Catch Basins"Standards No.5 See"Catch Basins"Standards No.5 li LANGLEY MEADOWS SECTION 10 I 107-016-006 OPERATIONS & MAINTENANCE MANUAL _ � _ - �-� Site Development Associates, LLC NO. 4- CONTROL STRUCTUREJFLOW RESTRICTOR Maintenance Defect Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed General Trash and Debris Distance between debris build-up and bottom of All trash and debris removed. (InGudes Sediment) orifice plate is less than 1-1/2 feet. Structural Damage Structure is not securely attached to manhole wall Structure secureiy attached to and outlet pipe structure should support at least wall and outlet pipe. 1,000 Ibs of up or down pressure. Structure is not in upright position(allow up to Structure in correct position. 10%from plumb). Connections to outlet pipe are not watertight and Connections to outlet pipe are show signs of rust. water tight;structure repaired or replaced and works as designed. Any holes—other than designed holes—in the SVucture has no holes other sVucture. than designed holes. Cleanout Gate Damaged or Missing Cleanout gate is not watertight or is missing. Gate is watertight and works as designed. Gate cannot be moved up and down by one Gate moves up and down easily maintenance person. and is watertight. Chain leading to gate is missing or damaged. Chain is in place and works as designed. Gate is rusted over 50%of its surface area. Gate is repaired or replaced to meet design standards.. Orifice Plate Damaged or Missing ConVol device is not working properly due to Plate is in place and works as missing,out of place,or bent orifice plate. designed. Obstructions Any trash,debris,sediment,or vegetation Plate is free of all obstructions blocking the plate. and works as designed. Overflow Pipe Obstructions Any trash or debris blocking(or having the Pipe is free of all obstructions potential of blocking)the overflow pipe. and works as designed. Manhole See"Closed Detention Systems"Standards No.3 See"Closed Detention Systems' Standards No.3 Catch Basin See"Catch Basins"Standards No.5 See`Catch Basins"Standards No. 5 LANGLEY MEADOWS SECTION 10 107-016-006 OPERATIONS& MAINTENANCE MANUAL -a,��" _ - Site Development Associates, LLC NO. 5-CATCH BASINS Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is performed General Trash&Debris Trash or debris of more than 1/2 cubic foot which is No Trash or debris located (InGudes Sediment) located immediately in front of the catch basin immediately in front of catch � opening or is blodcing capacity of the basin by basin opening. more than 10% Trash or debris(in the basin)that exceeds 1!3 the No trash or debris in the catch depth from the bottom of basin to invert the lowest basin. pipe into or out of the basin. Trash or debris in any iniet or outlet pipe blocking Inlet and outlet pipes free of more than 1/3 of its height. trash or debris. Dead animals or vegetation that could generate No dead animals or vegetation odors that could cause complaints or dangerous present within the catch basin. gases(e.g.,methane). Deposits of garbage exceeding 1 cubic foot in No condition present which volume would attract or support the breeding of insects or rodents. Structure Damage to Corner of frame extends more than 3/4 inch past Frame is even with curb. Frame and/or Top Slab curb face into the street(If applicabie). Top slab has holes larger than 2 square inches or Top siab is free of holes and cracks wider than 1/4 inch(intent is to make sure cracks. all material is running into basin). Frame not sitting flush on top slab, i.e.,separation Frame is sitting flush on top of more than 3/4 inch of the frame from the top slab. slab. Cracks in Basin Walls/ Cracks wider than 1/2 inch and longer than 3 feet, Basin replaced or repaired to Bottom any evidence of soil partiGes entering catch basin design standards. through cradcs,or maintenance person judges that structure is unsound. Cracks wider than 1/2 inch and longer than 1 foot No cracks more ihan 1/4 inch at the joint of any inleU outlet pipe or any evidence wide at the joint of inleUouUet of soil partiGes entering catch basin through pipe. cracks. SedimenU Basin has settled more than 1 inch or has rotated Basin replaced or repaired to Misalignment more than 2 inches out of alignment. design standards. LANGLEY MEADOWS SECTION 10 107-016-006 OPERATIONS & MAINTENANCE MANUAL � Site Deveiopment Associates, LLC , NO. 5- CATCH BASINS (CONTINUED) Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is pertortned Fire Hazard Presence of chemicals such as natural gas,oil and No flammable chemicals gasoline. present. Vegetation Vegetation growing across and blocking more than No vegetation blocking opening 10%of the basin opening. to basin. Vegetation growing in inleVoutlet pipe joints that is No vegetation orroot growth more than six inches tall and less than six inches present. apart. Pollution Nonflammable chemicals of more than 1/2 cubic foot No pollution present other than per three feet of basin length. surface film. Catch Basin Cover Cover Not in Place Cover is missing or only partially in place.Any open Catch basin cover is closed catch basin requires maintenance. Locking Mechanism Mechanism cannot be opened by on maintenance Mechanism opens with proper Not Working person with proper tools.Bolts into frame have less tools. than 1/2 inch of thread. Cover Difficult to One maintenance person cannot remove lid after Cover qn be removed by one Remove applying 80 Ibs.of lift;intent is keep cover from maintenance person. - sealing off access to maintenance. Ladder Ladder Rungs Ladder is unsafe due to missing rungs,misalignment, Ladder meets design standards Unsafe rust,cracks,or sharp edges. and allows maintenance person safe access. Metal Grates Grate with opening wider than 7/8 inch. Grate opening meets design (If Applicable) standards. Trash and Debris Trash and debris that is blocking more than 20°/o of Grate free of trash and debris. grate surface. Damaged or Grate missing or broken member(s)of the grate. Grate is in place and meets hlissing. design standards. LANGLEY MEADOWS SECTION 10 107-016-006 OPERATIONS & MAINTENANCE MANUAL � - Site Development Associates, LLC NO. 6 DEBRIS BARRIERS (E.G., TRASH RACKS) Maintenance Defect Condition When Maintenance is Needed Results Expected When Components Maintenance is Performed. General Trash and Debris Trash or debris that is plugging more than 20°/a of Barrier clear to receive capacity the openings in the barrier. flow. Metal Damaged/Missing Bars are bent out of shape more than 3 inches. Bars in place with no bends more Bars. than 3/4 inch. Bars are missing or entire barrier missing. Bars in place according to design. Bars are loose and rust is causing 50%deterioration Repair or replace barrier to to any part of barrier. design standards. LANGLEY MEADOWS SECTION 10 107-016-006 OPERATIONS & MAINTENANCE MANUAL � a-�� ____ Site Development Associates, LLC NO. 9 -GATES Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed General Damaged or Missing Missing gate or locking devices. Gates and Locking devices in Members place. Broken or missing hinges such that gate cannot Hinges intact and lubed.Gate is be easily opened and closed by a maintenance working freely. person. Gate is out of plumb more than 6 inches and Gate is aligned and vertical. more than 1 foot out of design alignment. Missing stretcher bar,stretcher bands,and ties. Stretcher bar,bands and ties in place. Openings in Fabric See"Fencing"Standard No.8 See"Fencing'Standard No. 8 LANGLEY MEADOWS SECTION 10 107-016-006 OPERATIONS & MAINTENANCE MANUAL � -_ _ �� Site Development Associates, LLC NO. 10- CONVEYANCE SYSTEMS (PIPES 8� DITCHES) Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed Pipes Sediment&Debris Accumulated sediment that exceeds 20°/a of the Pipe cleaned of all sediment and diameter of the pipe. debris. Vegetation Vegetation that reduces free movement of water All vegetation removed so water through pipes. flows freely through pipes. Damaged Protective coating is damaged;rust is causing Pipe repaired or replaced. more than 50%deterioration to any part of pipe. Any dent that decreases the cross section area of Pipe repaired or replaced. pipe by more than 20°ro. Open Ditches Trash&Debris Trash and debris exceeds 1 cubic foot per 1.000 Trash and debris cleared from square feet of ditch and slopes. ditches. Sediment Accumulated sediment that exceeds 20%of the Ditch cleaned/flushed of all design depth. sediment and debris so that it matches design. Vegetation Vegetation that reduces free movement of water Water flows freely through through ditches. ditches. Erosion Damage to See"Ponds"Standard No. 1 See"Ponds'Standard No. 1 Slopes Rock Lining Out of Place Maintenance person can see native soil beneath Replace rocks to design or Missing(If the rock lining. standards. Applicable). Catch Basins See"Catch Basins:Standard No.5 See`Catch Basins"Standard No.5 Debris Barriers See"Debris Barriers"Standard No.6 See"Debris Barriers"Standard (e.g.,Trash Rack) No.6 LANGLEY MEADOWS SECTION 10 107-016-006 OPERATIONS & MAINTENANCE MANUAL � �- :`�r� Site Development Associates, LLC . NO. 11 -GROUNDS (LANDSCAPING) Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed General Weeds Weeds growing in more than 20%of the landscaped Weeds present in less than 5% (Nonpoisonous) area(trees and shrubs only). of the landscaped area. Safety Hazard Any presence of poison ivy or other poisonous No poisonous vegetation vegetation. present in landscaped area. Trash or Litter Paper,cans,bottles,totaling more than 1 cubic foot Area clear of litter. within a landscaped area(trees and shrubs only)of 1,000 square feet. Trees and Shrubs Damaged Limbs or parts of trees or shrubs that are split or Trees and shrubs with less than broken which affect more than 25%of the total 5%of total foliage with split or foliage of the tree or shrub. broken limbs. Trees or shrubs that have been blown down or Tree or shrub in place free of knodced over. injury. Trees or shrubs which are not adequately supported Tree or shrub in place and or are leaning over,causing exposure of the roots. adequately supported;remove any dead or diseased trees. LANGLEY MEADOWS SECTION 10 107-016-006 OPERATIONS & MAINTENANCE MANUAL �'� � Site Development Associates, LLC NO. 12-ACCESS ROADS!EASEMENTS Maintenance Defect Condition When Maintenance is Needed Results Expected When Component Maintenance is Perfortned General Trash and Debris Trash and debris exceeds 1 cubic foot per 1,000 Roadway free of debris which square feet i.e.,trash and debris would fiIl up could damage tires. one standards size garbage can. Blodced Roadway Debris which could damage vehicle tires(glass Roadway free of debris which or metal). could damage tires. Any obstruction which reduces Gearance above Roadway overhead clear to 14 feet road surface to Iess than 14 feet. high. Any obstruction restricting the access to a 10 to Obstruction removed to allow at 12 foot width for a distance of more than 12 feet least a 12 foot access. or any point restricting access to less than a 10 foot width. Road Surface Settlement,Potholes, When any surface defect exceeds 6 inches in Road surface uniformly smooth Mush Spots,Ruts depth and 6 square feet in area.In general,any with no evidence of settlement. surface defect which hinders or prevents potholes,mush spots.or ruts. maintenance access. Vegetation in Road Weeds growing in the road surface that are more Road surface free of weeds taller Surface than 6 inches tall and less than 6 inches tall and than 2 inches. less than 6 inches apart within a 400-square foot area. Modular Grid Build-up of sediment mildly contaminated with Removal of sediment and disposal Pavement petroleum hydrocarbons. in keeping with Health DeparUnent recommendations for mildly contaminated soils or catch basin sediments. Shoulders and Erosion Damage Erosion within 1 foot of the roadway more than 8 Shoulder free of erosion and Ditches inches wide and 6 inches deep. matching the surrounding road. Weeds and Brush Weeds and brush exceed 18 inches in height or Weeds and brush cut to 2 inches in hinder maintenance access. height or cleared in such a way as to allow maintenance access. LANGLEY MEADOWS SECTION 10 107-016-006 OPERATIONS& MAINTENANCE ' MANUAL ;��.- � _ =�. Site Development Associates, LLC NO. 13 -WATER QUALITY FACILITIES E.) Wetvaults Maintenance Defect or Problem Condition When Maintenance is Needed Recommended Maintenance to Component Correct Problem Wetvault Trash/Debris Trash and debris accumulated in vault,pipe Remove trash and debris from vault. Accumulation or inleU outlet,(includes floatables and non- floatables). �I Sediment Sediment accumulation in vault bottom Remove sediment from vault. � Accumulation in Vauit exceeds the depth of the sediment zone plus 6-inches. Damaged Pipes InIeU ouUet piping damaged or broken and Pipe repaired and/or replaced. in need of repair. Access Cover Cover cannot be opened or removed, Pipe repaired or replaced to proper Damaged/Not especially by one person. working specifications. Working Ventilation Ventilation area blocked or plugged Remove or dear blocking material from ventilation area. A specified%of the vault surface area must provide ventilation to the vault interior(see p.6- 82 for required%). Vault Structure Vault:Cracks wider than 1/2-inch and any Repair cradcs wider than 1/4-inch at the Damaged evidence of soil particles entering the joint of the inleU outlet pipe.Make repairs sVucture through the cracks,or so that vault is structurally sound. maintenancel inspection personnel determines that the vault is not structuraliy sound. Baffles Baffles corroding,cracking,warping and/or Repair or replace baffles to showing signs of failure as determined by specifications. maintenance/inspection staff. Access Ladder Ladder is corroded or deteriorated,not Ladder replaced or repaired to Damage functioning properly,missing rungs,has specifications,and is safe to use as cracks and/or misaligned. Confined space determined by inspection personnel. waming sign missing. Repiace sign warning of confined space entry requirements. I � LANGLEY MEADOWS SECTION 10 107-016-006 OPERATIONS & MAINTENANCE MAN UAL �-a'- .