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Residential Drainage ApplicationDEPARTMENT OF COMMUNITY AND ECONOMIC DEVELOPMENT Page 1 of 3 | Published: 2/1/2018 Planning Division | 1055 South Grady Way, 6th Floor | Renton, WA 98057 | 425-430-7200 Website: rentonwa.gov RESIDENTIAL DRAINAGE APPLICATION Published: 2/1/2018 34TRESIDENTIAL ROADWAY/DRAINAGE IMPROVEMENT DETERMINATION REQUEST ON-LINE FORM34T IS REQUIRED TO BE SUBMITTED AND A DETERMINATION RESULT OBTAINED PRIOR TO SUBMITTING A RESIDENTIAL – SIMPLIFIED DRAINAGE OR BUILDING PERMIT APPLICATIONS. ALL PLANS AND ATTACHMENTS ARE SUBJECT TO 34TELECTRONIC FILE STANDARDS34T. PURPOSE: To ensure compliance with the City’s drainage requirements associated with residential single family development or redevelopment projects in accordance with City of Renton’s adopted standards (RMC 4-6-030), consistent with the City’s goal to protect public health, safety, welfare and aesthetics, and providing adequate public services/infrastructure. REQUIREMENTS: All residential developments that add impervious surface or have land disturbing activity are required to complete a Residential Drainage Application. Those developments that trigger drainage review shall comply with the requirements contained in the following Sections of the 2017 City of Renton Surface Water Design Manual (RSWDM): Appendix C.1 for Simplified Drainage Review, Appendix C.1.2 for Targeted Drainage Review, or Section 1.1.2.3 for Directed Drainage Review. EROSION AND SEDIMENT CONTROL IS REQUIRED FOR ALL PROJECTS RESULTING IN LAND DISTURBING ACTIVITY. Applicants are required to submit and obtain a determination of roadway improvements and storm drainage requirements prior to submitting for all residential building permits, with the exception of Interior Remodels, Pool/Spa, Fence Installation, and Photo-Voltaic Installation. A determination is obtained by submitting a 34TResidential Roadway/Drainage Improvement Determination Request On-line Form34T A Determination will be sent back to the recipient within three (3) business days following receipt of submittal. COMPLETE APPLICATION REQUIRED: In order to accept your Building Permit application, each of the items included in the Residential Drainage Application must be submitted concurrently with the Combination or Building Permit Application. APPLICATION INTAKE MEETING FOR APPLICATION SUBMITTAL: The Applicant is required to schedule an intake meeting with a Permit Technician to submit a Permit Application to the City for review. Intake meetings will be scheduled and held at the City’s Permit Center located on the 6th floor counter of Renton City Hall, 1055 South Grady Way, between 8:00 A.M. and 4:00 P.M. Monday through Friday. Please call 425-430-7200 to schedule an Intake Meeting with a Permit Technician. ADDITIONAL PERMITS AND REVIEW: Additional permits and/or drainage review may be required as part of this proposal. It is the Applicant’s responsibility to obtain these other approvals. Information regarding these other requirements may be found at the City’s webpage (rentonwa.gov) under the Surface Water Standards page. RESIDENTIAL DRAINAGE APPLICATION (CONT’D) Page 2 of 3 | Published: 2/1/2018 THRESHOLD: All Residential development in the City of Renton require either Drainage Evaluation or Drainage Review. Drainage Review is triggered for any residential development in the City of Renton that results in: 2,000 square feet or more of new plus replaced impervious surface; OR 7,000 square feet of land disturbing activity; OR Construction or modification of a pipe/ditch that is 12 inches or more in size/depth, or received storm water runoff or surface water from a drainage pipe/ditch that is 12 inches or more in size/depth; OR The project contains or is adjacent to a flood, erosion, or steep slope hazard area as defined in RMC 4-3-050, or is located within a Landslide hazard area in RMC 4-3-050. The type of drainage review is determined based upon the project and site characteristics. Those developments that do not trigger Drainage Review will require a Drainage Evaluation to ensure storm water is managed properly onsite to confirm that there is no erosion or flooding potential. DEFINITIONS: Impervious surface means a non-vegetated surface area that either prevents or retards the entry of water into the soil mantle as under natural conditions before development; or that causes water to run off the surface in greater quantities or at an increased rate of flow compared to the flow present under natural conditions prior to development (e.g., roofs, driveways, etc.). Common impervious surfaces include, but are not limited to, roof, walkways, patios, driveways, parking lots, or storage areas, areas that are paved, graveled or made of packed or oiled earthen materials or other surfaces that similarly impede the natural infiltration of surface water or stormwater. For the purposes of applying the impervious surface thresholds, permeable pavement, vegetated roofs, and pervious surfaces with underdrains designed to collect stormwater runoff are considered impervious surface while an open uncovered flow control or water quality facility is not. Land Disturbing Activity means any activity that results in a change in the existing soil cover (both vegetative and non- vegetative) and/or the existing soil topography. Land disturbing activities include, but are not limited to demolition, construction, clearing, grading, filling, excavation, and compaction. Land disturbing activity does not include tilling conducted as part of agricultural practices, landscape maintenance, or gardening. New impervious surface means the addition of a man-made, modified, or compacted surface like roofs, pavement, gravel, or dirt; or the addition of a more compacted surface, such as resurfacing by upgrading from dirt to gravel, asphalt, or concrete; upgrading from gravel to asphalt, or concrete; or upgrading from a bituminous surface treatment (“chip seal”) to asphalt or concrete. Permeable pavement and vegetated roofs are considered new impervious surface for purposes of determining whether the thresholds for application of minimum requirements are exceeded, as are lawns, landscaping, sports fields, golf courses, and other areas that have modified runoff characteristics resulting from the addition of underdrains designed to collect stormwater runoff. Open, uncovered retention/detention facilities shall not be considered impervious surfaces for purposes of determining whether the thresholds for application of minimum requirements are exceeded. Open, uncovered retention/detention facilities shall be considered impervious surfaces for purposes of runoff modeling. New pollution generating impervious surface (PGIS) means new impervious surface that is pollution-generating impervious surface or any alteration of existing pollution-generating impervious surface that changes the type of pollutants or results in increased pollution loads and/or concentrations. On-site BMP means small scale drainage facility or feature that is part of a development site strategy to use processes such as infiltration, dispersion storage evaporation, transpiration, forest retention, and reduced impervious surface footprint to mimic pre-developed hydrology and minimize stormwater runoff. RESIDENTIAL DRAINAGE APPLICATION (CONT’D) Page 3 of 3 | Published: 2/1/2018 Pervious surface means any surface material that allows stormwater to infiltrate into the ground. Examples include lawn, landscape, pasture, and native vegetation areas. Note for purposes of threshold determination and runoff volume modeling for detention and treatment, vegetated roofs and permeable pavements are to be considered impervious surfaces along with lawns, landscaping, sports fields, golf courses and other areas that have modified runoff characteristics resulting from the addition of underdrains. Pollution-generating impervious surface (PGIS) means an impervious surface considered to be a significant source of pollutants in stormwater runoff. Such surfaces include those that are subject to vehicular use, industrial activities, or storage of erodible or leachable materials, wastes, or chemicals and that receive direct rainfall or the run-on or blow- in of rainfall. A covered parking area would be considered PGIS if runoff from uphill could regularly run through it or if rainfall could regularly blow in and wet the pavement surface. Metal roofs are also considered PGIS unless they are coated with an inert, non-leachable material (see Reference Section 11-E); or roofs that are exposed to the venting of significant amounts of dusts, mists, or fumes from manufacturing, commercial, or other indoor activities. PGIS includes vegetated roofs exposed to pesticides, fertilizers, or loss of soil. Other roofing types that may pose risk but are not currently regulated are listed Reference Section 11-E. Lawns, landscaping, sports fields, golf courses, and other areas that have modified runoff characteristics resulting from the addition of underdrains that have the pollution generating characteristics described under the “pollution-generating pervious surface” definition are also considered PGIS. Pollution-generating pervious surface (PGPS) means a non-impervious surface considered to be a significant source of pollutants in surface and storm water runoff. Such surfaces include those that are subject to vehicular use, industrial activities, storage of erodible or leachable materials, wastes, or chemicals, and that receive direct rainfall or the run- on or blow-in of rainfall; or subject to use of pesticides and fertilizers, or loss of soil. Such surfaces include, but are not limited to, the lawn and landscaped areas of residential, commercial, and industrial sites or land uses, golf courses, parks, sports fields (natural and artificial turf), cemeteries, and grassed modular grid pavement. Replaced impervious surface means any existing impervious surface on the project site that is proposed to be removed and re-established as impervious surface, excluding impervious surface removed for the sole purpose of installing utilities or performing maintenance on underground infrastructure. For structures, removed means the removal of buildings down to the foundation. For other impervious surfaces, removed means the removal down to base course or bare soil. For purposes of this definition, base course is the layer of crushed rock that typically underlies an asphalt or concrete pavement. It does not include the removal of pavement material through grinding or other surface modification unless the entire layer of PCC or AC is removed. Replaced impervious surface also includes impervious surface that is moved from one location to another on the project site where the following two conditions are met: (A) runoff characteristics and volumes remain the same or are improved in the area where the existing impervious surface is removed , and (B) impervious surface at the new location is either designated as non-pollution generating or the pollution generating characteristics remain unchanged compared to that of the original location. Replaced pollution generating impervious surface (PGIS) means replaced impervious surface that is pollution-generating impervious surface. Specific Code Section(s) related to this document 34TRMC Ch 4-634T Street and Utility Standards 34TRMC Ch 4-834T Permits – General and Appeals Additional Design Resources and City Standards 34TCity of Renton Surface Water Design Manual (RSWDM)34T 34TCity of Renton Standard Details34T 34TCity of Renton Forms34T 34Surface Water Design Manual Definitions DEPARTMENT OF COMMUNITY AND ECONOMIC DEVELOPMENT Page 1 of 8 | Published: 2/1/2018 Planning Division | 1055 South Grady Way, 6th Floor | Renton, WA 98057 | 425-430-7200 Website: rentonwa.gov RESIDENTIAL DRAINAGE APPLICATION Applicant Information Name: Address: City: State: Zip: Phone: Email: Property Owner Information Name: Address: City: State: Zip: Phone: Email: Project Data Proposed Impervious Surface: Fill in all applicable blanks below to list the square footage of all new (or replaced) and existing impervious surface areas on your parcel. When calculating impervious surface areas for buildings do not list the living/useable space square-footage, instead list the building roof square-footage measured to the outside edge of the eve or gutter. IMPERVIOUS NEW EXISTING (to remain) TOTAL Roof Area (House, Attached Garage, Covered Patio, Covered Deck, Covered Porch)sq. ft. sq. ft. sq. ft. Roof Area (Detached Garage)sq. ft. sq. ft. sq. ft. Roof Area (All Out Buildings)sq. ft. sq. ft. sq. ft. On-site Driveway Area sq. ft. sq. ft. sq. ft. Off-site Driveway Area sq. ft. sq. ft. sq. ft. Walkways/Sidewalks/Stepping Stone Area sq. ft. sq. ft. sq. ft. Uncovered Porch and / or Patios Area sq. ft. sq. ft. sq. ft. Uncovered Decks Area sq. ft. sq. ft. sq. ft. Replaced Impervious Area (Considered New Impervious)sq. ft. sq. ft. sq. ft. All Other Impervious Areas sq. ft. sq. ft. sq. ft. Total New Impervious Surface Area sq. ft. Total Existing Impervious Surface Area sq. ft. Total Impervious Areas sq. ft. Total Clearing Limits, Site Disturbance / Graded Areas (Include Septic Drain fields Primary and Reserve) sq. ft. Total New Pervious Areas [(Total Clearing Limits, Site Disturbance/Graded Areas) – (Total New Impervious Areas)]sq. ft. Project Name: Project Address/Location: Parcel #(s): Description of Project: RESIDENTIAL DRAINAGE APPLICATION (CONT’D) Page 2 of 8 | Published: 2/1/2018 Drainage Review or Drainage Evaluation Required? The flow chart below identifies the drainage review/evaluation thresholds. Check the drainage review/evaluation that is required for the project. RESIDENTIAL DRAINAGE APPLICATION (CONT’D) Page 3 of 8 | Published: 2/1/2018 Submittal Requirements Basic Drainage Evaluation Road/Storm Improvement Determination Request and Results Residential Drainage Application ONLY (i.e. without intake checklist items) Simplified Drainage Review Road/Storm Improvement Determination Request and Results Residential Drainage Application including Simplified Drainage Review Intake Checklist items Targeted Drainage Review All items associated with Simplified Drainage Review Additional submittal requirements identified by RSWDM Appendix C Section 1.2 based on the identified site characteristic. Directed Drainage Review Road/Storm Improvement Determination Request and Results Residential Drainage Application including Directed Drainage Review Intake Checklist items Applicant Certification This application does not constitute a permit to work. Work shall not commence until a permit is issued. I certify that the information on this application is accurate to the best of my knowledge. Print Name Signature Date RESIDENTIAL DRAINAGE APPLICATION (CONT’D) Page 4 of 8 | Published: 2/1/2018 Simplified Drainage Review - Intake Checklist Use the following checklist as a guide to prepare the permit submittal package as well as the submittal checklist provided as part of the Residential Roadway/Drainage Improvement Determination. Marking an item as “Not Applicable” or “N/A”, without acceptable justification, may result in the submittal being rejected at Intake. See Example Simplified Drainage Review. Site Plan per Appendix C, Section C.4 of the 2017 (RSWDM). Must be plotted to scale, with all significant dimensions given. Site plans, should be drawn on 8½" x 11", with 1” clear border, minimum 9 pt font, and no hatching. Included N/A All Checklists/Studies/Reports Required Unless Waived by City Staff Identification _____Name, address, and phone number of Applicant _____ Parcel number _____Dimension of all property lines, easements, and building setback lines _____Street names and existing or proposed property address _____Section, township and range of proposal _____North arrow _____Legend if needed _____Scale—use a scale that clearly Building and Site Development Features _____Footprint of all structures (existing and proposed) _____Parking, roads, and driveways (existing and proposed) _____Sport courts and any other paved or impervious surfaces (existing and proposed) _____Pervious surfaces land cover (existing and proposed) _____Location of any retaining walls and rockeries (existing and proposed) _____Existing or proposed septic system, including all system components and both primary and reserve drainfields. _____Utility structures (poles, fire hydrants, etc.) _____Existing wells or wells to be abandoned Topography _____Corner elevations of the site/lot _____Benchmark (a permanent mark indicating elevation and serving as a reference in the topographic survey) _____Datum [assumed datum is acceptable in many cases (i.e., fire hydrant base = 100’); datum for projects in or near FEMA floodplain should be per the relevant Flood Insurance rate Mat (FIRM) (typically NGVD 1929, or NAVD 1988 on many recent updated maps; datum for project in or near unmapped floodplain shall use NAVD 1988) _____Show 5-foot contours for all slopes steeper than 15% and delineate the top and bottom of these slopes _____For sites/lots that are 22,000 square feet and larger, show 2-foot or 5-foot contours as needed to design and demonstrate compliance with the minimum design requirements and specifications for proposed on-site BMPS and ESC and SWPPS measures Drainage Features and Critical Areas For a map detailing the critical areas on your site, visit the Self Help Area in City’s Permit Center or the City’s GIS Mapping System. Developments within 200 feet of a critical area may require an engineered drainage plan. _____Location of all existing and proposed ditches, swales, pipes, etc. _____Delineation of all streams, wetlands, lakes, closed depressions, or other water features (including any required buffer widths) _____Delineation of all flood hazard areas, erosion hazard areas, landslide hazard areas, and their buffers and building setback lines. _____Delineation of all drainage easements, tracts and right-of-way _____Delineation of all critical areas as shown on any recorded critical areas notice on title RESIDENTIAL DRAINAGE APPLICATION (CONT’D) Page 5 of 8 | Published: 2/1/2018 Site Plan (Cont’d) Included N/A All Items Required Unless Waived by City Staff Information Specific to On-Site BMPs (Section C.4.2.2 of the RSWDM) _____ Location and dimensions of On-Site BMP devices such as dispersion trenches, infiltration trenches, drywells, ground surface depressions, bioretention, permeable pavements, rain water storage tanks, and perforated pipe connections for managing stormwater from all impervious surfaces. _____ Delineation and dimensions of target impervious surface and new pervious surface _____Delineation and dimensions of vegetated flowpath segments if applicable. _____Delineation of native vegetated surface to be created and preserved BMP Design and Maintenance Details per Section C.4.3 of the 2017 RSWDM. Included N/A All Items Required Unless Waived by City Staff _____ Provide diagrams/figures (should be displayed on 8½" x 11" format with 1-inch margins so they can be directly recorded as attachments to the required declaration of covenant and grant of easement), design specifications, and maintenance instructions for each On-Site BMP proposed. _____ Provide maintenance instructions explaining for future property owners the purpose of each On-Site BMP and how it must be maintained and operated. Small Site or Construction Stormwater Pollution Prevention (CSWPP) Plan [formally Erosion and Sediment Control (ESC) Plan] per Section C.4.2.2 of the 2017 RSWDM. Erosion and sediment control is required for all projects resulting in land disturbing activity. Included N/A All Items Required Unless Waived by City Staff _____ Delineation of proposed clearing limits (i.e., area to be disturbed) _____ Type and location of ESC and SWPPS measures such as: construction entrance, mulching, nets and blankets plastic covering, clearing Limits/Minimize Clearing, silt fence, vegetated strip, triangular silt dike, storm drain inlet protection. _____Notes indicating the location of any significant offsite drainage features within 200 feet of the discharge point(s) for the site/lot, including streams, lakes, roadside ditches, etc. Written Drainage Assessment per Section C.4.4 of the 2017 RSWDM. Included N/A All Items Required Unless Waived by City Staff _____ A narrative description of proposed project _____ Any proposed changes to the project after preliminary approval _____A description of proposed on-site BMPs shown on the site plan and how they were selected _____Supporting documentation (e.g., soil tests, infiltration rates, geotechnical recommendations, etc.) where BMPs were not selected based upon determination of infeasibility. _____A description of proposed ESC and SWPPS Measures shown or noted on the plans and how they were selected. _____A description of any necessary special studies or soils reports _____A description of any other information required by CED RESIDENTIAL DRAINAGE APPLICATION (CONT’D) Page 6 of 8 | Published: 2/1/2018 Soils Report per Section C.1.3 of the 2017 RSWDM (additional requirements noted in RSWDM) Included N/A All Items Required Unless Waived by City Staff _____ Prepared by or under the direction of a licensed onsite sewage system design or geotechnical professional (e.g., licensed engineer with geotechnical and/or hydrogeologic experience, licensed geologist, hydrogeologist, or engineering geologist. _____ Must include at least one soils log for each proposed infiltration location _____Must demonstrate the feasibility of full infiltration, limited infiltration, permeable pavement, and bioretention BMPs where treating pollution generating surfaces. Not required if treating non-pollution generating surfaces only. _____Infiltration testing required to demonstrate the feasibility of bioretention and permeable pavement BMPs for the site/lot (see additional requirements for infiltration testing in Section C.1.3 of the 2017 RSWDM) Declaration of Covenant per Section C.5.2 of the 2017 RSWDM. Declaration of Covenant is for Maintenance and Inspection of On-Site BMPs. See Example Declaration of Covenant. Included N/A All Items Required Unless Waived by City Staff _____ Fill out Declaration of Covenant Form. _____ Attach the Simplified Drainage Site Plan as Exhibit A. Site plans, must be drawn on 8½" x 11", with 1” clear border, minimum 9 pt font, and no hatching. _____Attach Maintenance Instructions for On-Site BMP(s). See City of Renton Surface Water Design Manual Reference 8-M for On-Site BMP Covenant and Maintenance Instructions in recordable format with 1” clear border, and minimum 9 pt font. RESIDENTIAL DRAINAGE APPLICATION (CONT’D) Page 7 of 8 | Published: 2/1/2018 Directed Drainage Review - Intake Checklist Use the following checklist as a guide to prepare the permit submittal package as well as the submittal checklist provided as part of the Residential Roadway/Drainage Improvement Determination. Marking an item as “Not Applicable” or “N/A”, without acceptable justification, may result in the submittal being rejected at Intake. Civil Construction Plans per Section 2.3.1.2 of the 2017 RSWDM Organize the plans such that they are separated into type of improvement and drawing order. Each improvement type should include all plans, profiles, notes, sections, details, schedules, diagrams, etc. for that facility. All plans shall be designed in accordance with the City of Renton “Construction Plan Drafting Standards” as required per RMC 4-8-120. The required order of drawings is as follows: Included N/A All Plans Required Unless Waived by City Staff _____ Cover Sheet _____ Existing Conditions/Topography Plan _____ Site Plan _____ Temporary Erosion and Sediment Control Plan _____ Grading Plan (may be combined with Temporary Erosion and Sediment Control Plan or Storm Drainage Plan) _____ Conceptual Structural/Retaining Wall and/or Detention Vault Plans Associated with Civil Improvements _____ Road/Paving/Storm Drainage Plan and Profiles (Large Projects May Require Separate Street Improvement and Storm Drainage Plans) _____ Wastewater and Water Utility Plan and Profiles (Large Projects May Require Separate Wastewater and Water Plans) _____ City Standard Details (Organized by Private vs. Public) _____ Landscaping Plan and Details _____ Tree Retention/Land Clearing (Tree Inventory) Plan _____ Wetland or Stream Mitigation Plan _____ Miscellaneous Plans (Structural, Architectural, etc.) Declaration of Covenant per Section C.5.2 of the 2017 RSWDM. Declaration of Covenant is for Maintenance and Inspection of On-Site BMPs. See Example Declaration of Covenant. Included N/A All Items Required Unless Waived by City Staff _____ Fill out Declaration of Covenant Form. _____ Attach a Site Plan as Exhibit A. Site plans, must be drawn on 8½" x 11", with 1” clear border, minimum 9 pt font, and no hatching. _____Attach Maintenance Instructions for On-Site BMP(s). See City of Renton Surface Water Design Manual Reference 8-M for On-Site BMP Covenant and Maintenance Instructions in recordable format with 1” clear border, and minimum 9 pt font. RESIDENTIAL DRAINAGE APPLICATION (CONT’D) Page 8 of 8 | Published: 2/1/2018 Technical Information Report per Section 2.3.1.1 of the 2017 RSWDM The Technical Information Report (TIR) shall be a complete report in accordance with the 2017 Renton Surface Water Design Manual. Each section of the report shall be clearly identified and all supporting documents clearly indexed within the report. Included TIR shall Include the Following Items as detailed in the Surface Water Design Manual Section 1: Project Overview Figure 1 – TIR Worksheet Figure 2 – Site Location Figure 3 – Drainage Basins, Sub-basins and Site Characteristics o Show acreage and boundaries of sub-basins o Identify all site characteristics o Show existing discharge points to and from the site o Show routes of existing, construction, and future flows at all discharge points and downstream hydraulic structures o Topographic map as a base for the figure comparable to USGS or better. Show (and cite) the length of travel from the farthest upstream end of the proposed storm system in the development to any proposed flow control facility. Figure 4 – Soils (Show the soils within the following areas): o The project site o The area draining to the site o The drainage system downstream of the site for the distance of the downstream analysis Section 2: Conditions and Requirements Summary Section 3: Off-Site Analysis Task 1: Study Area Definition and Maps Task 2: Resource Review Task 3: Field Inspection Task 4: Drainage System Description and Problem Descriptions Task 5: Mitigation of Existing or Potential Problems Section 4: Flow Control, Low Impact Development (LID), and Water Quality Facility Analysis and Design Existing Site Hydrology (Part A) – Topographical map with listed site information Developed Site Hydrology (Part B) – Data/narrative for developed site conditions Performance Standards (Part C) – Summarize flow control and On-Site BMPs Flow Control System (Part D) – Illustrative sketch and documentation Water Quality System (Part E) – Illustrative sketch and documentation Section 5: Conveyance System Analysis and Design Section 6: Special Reports and Studies (Geotechnical Reports, Wetlands Reports, Floodplains Analysis, etc.) Section 7: Other Permits (Special Use, WSDOT, DOE Permit with WAR #, etc.) Section 8: CSWPPP Analysis and Design ESC Plan Analysis and Design (Part A) SWPPS Plan Design (Part B) Section 9: Bond Quantities, Facility Summaries and Declaration of Covenant City of Renton Bond Quantity Worksheet Flow Control and Water Quality Facility Summary Sheet and Sketch Declaration of Covenant for Privately Maintained Flow Control and Water Quality Facilities Declaration of Covenant for Privately Maintained Flow Control BMPs Section 10: Operations and Maintenance Manual