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HomeMy WebLinkAboutdo not use - delete file0 GRAPHIC SCALE 453015 1 INCH = 30 FT. MAINTENANCE INSTRUCTIONS FOR BASIC DISPERSION Your property contains an on-site BMP (best management practice) called “basic dispersion,” which was installed to mitigate the stormwater quantity and quality impacts of some or all of the impervious surfaces or non-native pervious surfaces on your property. Basic dispersion is a strategy for utilizing any available capacity of onsite vegetated areas to retain, absorb, and filter the runoff from developed surfaces. This on-site BMP has two primary components that must be maintained: (1) The devices that disperse runoff from the developed surfaces and (2) The vegetated area over which runoff is dispersed. Dispersion Devices The dispersion devices used on your property include the following as indicated on the site plan (CHECK THE BOX(ES) THAT APPLY):  splash blocks,  rock pads,  gravel filled trenches,  sheet flow. MAINTENANCE RESTRICTIONS The size, placement, composition, and downstream flowpaths of these devices as depicted by the site plan and design details must be maintained and may not be changed without written approval from the City of Renton or through a future development permit from the City of Renton. INSPECTION FREQUENCY AND MAINTENANCE GUIDELINES This on-site BMP has two primary components that must be maintained per Appendix A of the City of Renton’s Surface Water Design Manual: (1) The devices that disperse runoff from the developed surfaces and (2) The vegetated flowpath area over which runoff is dispersed. Maintenance of Dispersion Devices • Dispersion devices must be inspected annually and after major storm events to identify and repair any physical defects. • When native soil is exposed or erosion channels are present, the sources of the erosion or concentrated flow need to be identified and mitigated. • Concentrated flow can be mitigated by leveling the edge of the pervious area and/or realigning or replenishing the rocks in the dispersion device, such as in rock pads and gravel filled trenches. Maintenance of Vegetated Flowpaths • The vegetated area over which runoff is dispersed must be maintained in good condition free of bare spots and obstructions that would concentrate flows. PLAN VIEW OF PARCEL TO STORM DRAINSYSTEMRIGHT- OF-WAYGENERAL NOTES:1.INFILTRATION TRENCHES LIMITED TO ROOF RUNOFF FROM SINGLE-FAMILY OR DUPLEX HOMES OR TO CONTROL BASEMENT FLOODING. CONSULT WA DEPARTMENT OF ECOLOGY REGULATIONS FOR UNDERGROUND INJECTION CONTROL PROGRAM (UIC) FOR OTHER TYPES OF RUNOFF MANAGEMENT.2.IMPERVIOUS AREAS LARGER THAN 10,000 SF AND NON-NATIVE PERVIOUS AREAS LARGER THAN 35,000 SF MAY REQUIRE LARGER PIPE AND SHOULD BE DESIGNED BY A CIVIL ENGINEER.3.THE PERFORATED PIPE MAY NOT BE PLACED IN A CRITICAL AREA BUFFER OR ON SLOPES STEEPER THAN 25%.4.SEE CONSTRUCTION PLANS FOR SPECIFIC PROJECT REQUIREMENTS.24" MIN.18" MIN.MIN. 1' ABOVE SEASONAL HIGH GROUNDWATER TABLE 6" MIN.3/4" - 11/2" WASHED DRAIN ROCK OR GRAVEL BACKFILL FOR DRYWELLS PER WSDOT STD.SPECIFICATION SECTION 9-03.12( 5)NON-WOVEN GEOTEXTILE FOR SEPARATION ON TOP AND SIDES OF TRENCH PER WSDOT SPECIFICATIONS SECTION 9-33.2(1) TABLE 3 COMPACTED TOPSOIL OR OTHER CLEAN FILL 6" DIA. MIN.PERFORATED PVC,SDR 35 PER ASTM D3034 10' MIN. LEVEL TRENCH WITH PERFORATED PIPE, SEE NOTE 1 DOWNSPOUT WITH CLEANOUT FILTER, SEE DETAIL ASECTION A NOTES:1.TRENCH LENGTH TO BE 10 FEET IN LENGTH FOR EVERY 5,000 SF OF CONTRIBUTING IMPERVIOUS SURFACE, OR 35,000 SF OF NON-NATIVE PERVIOUS SURFACE, OR PORTION THEREOF. 5' MIN. 5' MIN.TO STORM DRAIN SYSTEM 5' MIN. 5' MIN. A DOWNSPOUT WITH CLEANOUT FILTER, SEE DETAIL 10' MIN. LEVEL TRENCH WITH PERFORATED PIPE, SEE NOTE 1 CONFIGURATION ON FLAT GROUND CONFIGURATION ON SLOPING GROUND UNDISTURBED NATIVE SOIL CLEANOUT PER STD. PLAN 226. 00 CLEANOUT PER STD. PLAN 226. 00 FILTER SCREEN 2'-5' TO GROUND SOLIDS/ LEAVES TYPICAL DOWNSPOUT FILTER DETAIL FOOTING DRAIN BYPASS CLEANOUT PER STD. PLAN 226. 00 PERFORATED STUB- OUT CONNECTION PUBLIC WORKS DEPARTMENT APPROVED:DATEMartin Pastucha Public Works AdministratorUNLESS OTHERWISE NOTED, DRAWINGISNOTTO SCALE ( NTS)STD. PLAN - 263. 40 DocuSign Envelope ID: A9707D3B-A0EF-441F-8140- 2CDB48E878CA 11/2/2020 | 1:04 PM MAINTENANCE INSTRUCTIONS FOR A PERFORATED PIPE CONNECTION Your property contains an on-site BMP (best management practice) called a “perforated pipe connection,” which was installed to reduce the stormwater runoff impacts of some or all of the impervious surface on your property. A perforated pipe connection is a length of drainage conveyance pipe with holes in the bottom, designed to “leak” runoff, conveyed by the pipe, into a gravel filled trench where it can be soaked into the surrounding soil. The connection is intended to provide opportunity for infiltration of any runoff that is being conveyed from an impervious surface (usually a roof) to a local drainage system such as a ditch or roadway pipe system. This on-site BMP shall be maintained per Appendix A of the City of Renton’s Surface Water Design Manual. MAINTENANCE RESTRICTIONS • The size and composition of the perforated pipe connection as depicted by the site plan and design details must be maintained and may not be changed without written approval from the City of Renton or through a future development permit from the City of Renton. • The soil overtop of the perforated portion of the system must not be compacted or covered with impervious materials. RECORDING REQUIREMENT These perforated pipe connection on-site BMP maintenance and operation instructions must be recorded as an attachment to the required declaration of covenant and grant of easement per Requirement 3 of Section C.1.3.4 of the City of Renton Surface Water Design Manual. The intent of these instructions is to explain to future property owners, the purpose of the BMP and how it must be maintained and operated. These instructions are intended to be a minimum; the City of Renton may require additional instructions based on site-specific conditions. See the City of Renton’s Surface Water Design Manual website for additional information and updates. TYPICAL PERFORATED PIPE CONNECTION FOR A SINGLE FAMILY RESIDENCE NOTES: SECTION VIEW ISOMETRIC VIEW DRAINAGE GRATE TRIM GRATE FRAME FILTERED WATER SEDIMENT AND DEBRIS OVERFLOW BYPASS BELOW INLET GRATE DEVICE DRAINAGE GRATE RECTANGULAR GRATE SHOWN)RETRIEVAL SYSTEM (TYP.) OVERFLOW BYPASS (TYP.) BELOW INLET GRATE DEVICE 1.PROTECTION SHALL BE PROVIDED FOR ALL STORM DRAIN INLETS DOWNSLOPE AND WITHIN 500 FEET OF A DISTURBED OR CONSTRUCTION AREA, UNLESS THE RUNOFF THAT ENTERS THE CATCH BASIN WILL BE CONVEYED TO A SEDIMENT POND OR TRAP. 2.INLET PROTECTION SHALL BE USED TO PROTECT THE DRAINAGE SYSTEM. 3.THE CONTRIBUTING DRAINAGE AREA MUST NOT BE LARGER THAN ONE ACRE. 4.SIZE THE BELOW INLET GRATE DEVICE (BIGD) FOR THE STORMWATER STRUCTURE IT WILL SERVICE. 5.THE BIGD SHALL HAVE A BUILT-IN HIGH-FLOW RELIEF SYSTEM (OVERFLOW BYPASS). 6.THE RETRIEVAL SYSTEM MUST ALLOW REMOVAL OF THE BIGD WITHOUT SPILLING THE COLLECTED MATERIAL. 7.PERFORM MAINTENANCE IN ACCORDANCE WITH STANDARD SPECIFICATION 8-01.3(15). 8.ANY SEDIMENT IN THE CATCH BASIN INSERT SHALL BE REMOVED WHEN THE SEDIMENT HAS FILLED ONE-THIRD OF THE AVAILABLE STORAGE. THE FILTER MEDIA FOR THE INSERT SHALL BE CLEANED OR REPLACED AT LEAST MONTHLY. 5" MAX. CATCH BASIN INSERT STD. PLAN - 216.30 PUBLIC WORKS DEPARTMENT APPROVED: DATEGreggZimmerman Public Works Administrator UNLESS OTHERWISE NOTED, DRAWING IS NOT TO SCALE (NTS) DocuSign Envelope ID: 6EECF5B6-602A-4E4A-B436-A317AA638878 9/28/2018 | 9:45 AM PDT MAINTENANCE INSTRUCTIONS FOR SOIL AMENDMENT Your property contains an on-site BMP (best management practice) called “soil amendment,” which was installed to mitigate the stormwater quantity and quality impacts of some or all of the pervious surfaces on your property. Soil amendment is a method of regaining greater stormwater functions in the post development landscape by increasing treatment of pollutants and sediments, and minimizing the need for some landscaping chemicals. To be successful, the soil condition must be able to soak water into the ground for a reasonable number of years. This on-site BMP shall be maintained per Appendix A of the City of Renton’s Surface Water Design Manual. MAINTENANCE RESTRICTIONS The size, placement, and composition of these devices as depicted by the site plan and design details must be maintained and may not be changed without written approval from the City of Renton or through a future development permit from the City of Renton. INSPECTION FREQUENCY AND MAINTENANCE GUIDELINES To be successful, the soil must be able to soak water into the ground for a reasonable number of years. • Return leaf fall and shredded woody materials from the landscape to the site when possible in order to replenish soil nutrients and structure. • On turf areas, “grasscycle” (mulch-mow or leave the clippings) to build turf health. • Maintain 2 to 3 inches of mulch over bare areas in landscape beds. • Re-seed bare turf areas until the vegetation fully covers the ground surface. • Avoid using pesticides (bug and weed killers) which damage the soil. • Where fertilization is needed (mainly turf and annual flower beds), a moderate fertilization program should be used which relies on compost, natural fertilizers, or slow-release synthetic balanced fertilizers. RECORDING REQUIREMENT These on-site BMP maintenance and operation instructions must be recorded as an attachment to the required declaration of covenant and grant of easement per Requirement 3 of Section C.1.3.4 of the City of Renton Surface Water Design Manual. The intent of these instructions is to explain to future property owners, the purpose of the BMP and how it must be maintained and operated. These instructions are intended to be a minimum; the City of Renton may require additional instructions based on site-specific conditions. See the City of Renton’s Surface Water Design Manual website for additional information and updates.