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HomeMy WebLinkAboutSWP273058 (2) ' NPDES Phase II Regulatory Review City of Renton ' Stormwater Utility tDecember2o02 1 CITY OF RENTON ' NPDES REGULATORY REVIEW Table of Contents Table of Contents tList of Tables Section 1. Introduction, Purpose, and Scope Section 2. Overview of NPDES h P ase II ' Federal Stormwater Management Policy ..........................................................2-1 NPDES Phase II Objectives ..............................................................................2-1 NPDESPhase II Rules ......................................................................................2-2 NPDES Phase II Permitting Authority for the State of Washington.................2-2 ' Federal Stormwater Management Requirements under NPDES Phase II.........2-3 BMPs for Six Minimum Control Measures.......................................................2-4 ' Measurable Goals for Control Measures...........................................................2-6 Implementation Schedule of Activities or Frequency of Activities..................2-6 Entity Responsible for Implementation.............................................................2-6 Phase II Permitting Process...............................................................................2-7 ' NDPES Phase II Ongoing Requirements..........................................................2-7 NDPES Phase II and TMDLs...........................................................................2-8 1 Summary of NPDES Phase II Requirements ....................................................2-9 City Departments/Public Affected by NPDES Phase II Requirements.............2-9 Section 3. Evaluation of Stormwater Design Manuals Stormwater Management Manual for Western Washington (Ecology, 2001)..3-1 1998 King County Surface Water Design Manual (KCS)vVDM)(King ' - County, 1998) 3-3 .................................... 1990 KCSWDM (amended 1994)......................................................................3-4 ' Section 4. Consideration for Selecting a New Design Manual Option of Creating New City of Renton Manual with Equivalent Standards...4-1 Option of Adopting 1998 King County Surface Water Design Manual ...........4-2 Aquifer Protection Ordinance.........:..................................................................4-3 Obtaining Project Permits...........................-....... ---------................... ..............4-3 Summary of Advantageous and Disadvantageous for Manual Alternatives.....4-4 Appendices A. PowerPoint Presentations ' B. Questions and Answers from Ecology and King County 1 ' X001159_3335 12/31/02 Table of Contents ' List of Tables , 2-1. Minimum Reporting Requirements.....................................................................2-8 2-2. Summary Table of NPDES Phase Il Requirements ............................................2-9 , 2-3. Summary Table of City Departments/Public Affected by NPDES Phase 11 Requirements ...................................................................................2-10 3-1. Stormwater Manual Comparison.........................................................................3-5 ' 4-1. Stormwater Manuals and Advantageous and Disadvantageous..........................4-4 1 t _ - 1 This report has been prepared for the use of the client for the specific purposes identified in the ' report. The conclusions, observations and recommendations contained herein attributed to R.W. Beck, Inc. (R.W. Beck) constitute the opinions of R.W. Beck. To the extent that statements, information and opinions provided by the client or others have been used in the ' preparation of this report, R.W. Beck has relied upon the same to be accurate,and for which no assurances are intended and no representations or warranties are made. R.W. Beck makes no certification and gives no assurances except as explicitly set forth in this report. Copyright 2002, R.W. Beck, Inc. ' All rights reserved. t 11 X001157_3335 12!31102 ' r Section 1 INTRODUCTION, PURPOSE, AND SCOPE i The purpose of this study is to provide the City of Renton an understanding of the pending Federal National Pollutant Discharge Elimination System (NPDES) Phase II regulations and its impact on the City's stormwater program. On December 8, 1999 the Federal government as part of the Clean Water Act issued final regulations to implement the National Pollutant Discharge Elimination System (NPDES) Stormwater program for smaller communities. Phase I of the NPDES Stormwater program was implemented in 1-990, which addressed priority sources of pollutant runoff, including stormwater pollution from cities with more than 100,000 population. These new. regulations issued in 1999 are for Phase II of this program and.are therefore often referred to as the NPDES Phase II Rule. Demographics and location of the City of ' Renton are such that the City is required to obtain a new NPDES Stormwater Permit under the Phase II Rule. This permit will be administered by the Washington State Department of Ecology (Ecology) since Ecology has NPDES permitting authority in ' this state. Ecology has indicated they will write a "General" permit listing requirements for all Phase II permitees as opposed to writing individual permits for all permitees. rOne of the key NPDES compliance issues of interest for the City is adoption of a stormwater design manual. One of the anticipated requirements of the NPDES Phase II general permit to be issued by Ecology is that municipalities like Renton must adopt Ecology's 2001 Stormwater Management Manual for Western Washington (SWMM) or an equivalent manual. Ecology developed the SWMM as one of its initial steps to ' comply with the NPDES Phase II Rule. At the present time, the City adopts by reference the 1990 King County Design Manual. It is problematic to continue using the 1990 manual because it is no longer in print given that King County adopted an updated version in 1998. There are also significant differences between the SWMM and the 1990 King County Design Manual such that the 1990 King County manual is not equivalent to the SWMM and therefore not likely to comply with Ecology's rNPDES Phase II general permit. In an effort to assist the City in understanding the-differences between stormwater manuals, a summary of the differences between Ecology's 2001 Stormwater Management Manual, the 1998 King County Surface Water Design Manual (KCSWDM), and the 1990 KDSWDM was prepared. r Another objective of this study was to define, at least on a preliminary level, who will be affected. Compliance with the NDPES Phase II Rule will have far reaching consequences involving many of the City's departments and citizens. For example, ' the new Federal regulations will reduce the threshold requiring NPDES Stormwater" permits for construction activities from 5 acres down to 1 acre. Thus, City road, park, or public works projects as well as private projects disturbing more than 1 acre will r need to obtain an NPDES permit for construction activities. The new drainage standards and new permits will affect the City's development review process. New r rX001159_3 335 12,27/02 Section 1 t requirements for operation and maintenance will affect both City and private facility r owners. New requirements for public outreach and education may require new approaches with multiple city departments. I f._..._,_ F r this +,„-.� :=Tas developed in collaboration with City staff and r i ne scope o� work, �..� �..�� sou..,, r_- included the following; ■ Prepare an overview of the NPDES Phase II program. The overview is not r intended to be an audit of the City's program (i.e., evaluating what the City is doing and how to respond). Rather, it is intended to be an overview of the Federal rule. ' ■ Prepare a matrix evaluation comparing the minimum requirements of Ecology's Stormwater Management Manual for Western Washington (August 2001), the r 1998 KCSWDM, and the 1990 KCSWDM. The comparison focuses on the SWMM's ten minimum requirements as well as exemptions and variances. ■ Contact representatives of the Washington State Department of Ecology ' (Ecology) as well as the King County Department of Natural Resources to gather information on the status of their respective drainage manuals. ■ Lay out key decisions or options that need to be considered to help determine an r approach to updating the City's stormwater standards. ■ Prepare a power point presentation summarizing information developed as a part ' of the study. Section 2 of the report includes the overview of the NPDES Phase II program ' requirements. Section 3 of the report includes the evaluation of the three drainage manuals and provides an introduction of the status of each of the manuals. Section 4 includes a discussion of considerations about the options for adopting new stormwater , standards. The power point presentation is included on a disk in Appendix A. The power point presentation is divided into two sections, one summarizing the NDPES Phase II requirements and one that summarizes the evaluation of drainage manuals. r Appendix A also contains hard copies of the presentations. Appendix B contains a summary of the questions and answers posed to Ecology and King County regarding the status of the manuals. r r r r r 1-2 R. W. Beck X001159_3335 12/27/02 r Section 2 OVERVIEW OF NPDES PHASE II Federal Stormwater Management Policy On December 8, 1999 the Federal government as part of the Clean Water Act issued final regulations to implement the National Pollutant Discharge Elimination System (NPDES) Stormwater program for smaller communities. Phase I of the NPDES Stormwater program was implemented in 1990, which addressed priority sources of pollutant runoff, including stormwater pollution from medium and large (>100,000 population) municipal separate storm sewer systems (MS4s), industrial sources, and construction sites disturbing at least five acres. These new regulations issued in 1999 are for Phase II of this program are therefore called the NPDES Phase II Rule. Demographics and location of the City of Renton are such that the City is required to obtain a new NPDES Stormwater Permit under the Phase II Rule. This rule is ' designed to comply with the requirements of the Clean Water Act (CWA) to further protect our nation's streams, rivers and beaches from polluted stormwater runoff. NPDES Phase II Objectives The United States Environmental Protection Agency's (EPA's) objectives in developing the Phase II regulations include: ■ Provide a comprehensive stormwater program that designates and controls ' additional sources of stormwater discharges to protect water quality, pursuant to CWA Section 402 (p)(6) ■ Address discharges of stormwater activities not addressed by Phase I, including: ■ All construction site activities involving clearing, grading and excavating land equal to or greater than one acre (including projects that are comprised of several sites of less than one acre each) ■ "Light" industrial activities not exposed to stormwater ■ Municipal Separate Stormwater Sewer Systems (MS4s) located in urbanized areas not covered under Phase I ■ Municipally owned industrial facilities that were addressed under Phase I but granted an extension under ISTEA (Intermodal Surface Transportation Efficiency Act). In 1991, provisions within ISTEA temporarily exempted ' storm water discharges associated with industrial activities at facilities operated by municipalities (such as non-point runoff from wastewater sewage treatment plants, vehicle maintenance area, and solid waste handling ' facilities) with populations of less than 100,000 (with the exception of power plants, airports, and uncontrolled sanitary landfills) from the need to obtain ' X001159 3335 12/27/02 Section 2 ' an NPDES industrial storm water permit. Under the provisions of the NPDES Stone Water Program Phase II Final Rule, these industrial facilities will ' require permit coverage beginning March 10, 2003. ■ Facilitate and promote watershed planning as a framework for implementing ' water quality programs wherever possible EPA aims to achieve these objectives by balancing nationwide automatic designation and locally based designation. EPA will designate on a nationwide basis: ■ Storwater discharges from small MS4s located in urbanized areas ■ Construction activities that result in land disturbance equal to or greater than one acre EPA believes that this designation criteria addresses the main sources of stormwater ' pollution causing significant degradation of surface waters. States that have NPDES permitting authority (see subsequent definition of permitting authority) may designate additional small MS4s, categories or individual sources of stormwater discharges that ' are problematic in specific communities. NPDES Phase II Rules The NPDES Phase II Rules covers the following: ' ■ Small MS4s (serving a population of less than 100,000 and located in an urbanized area or designated by the pennitting authority) ' ■ Construction activities disturbing between one and five acres ■ Industrial sources designated by the permitting authority ■ ISTEA sources (including municipally-owned/operated industrial facilities) NPDES Phase II Permitting Authority for the State of Washington The State of Washington is authorized to administer the Federal NPDES program in this state and the Washington State Department of Ecology is the permitting agency . who will have responsibility for the following: ■ Provide waivers ■ Issue permits (Ecology has the option of issuing individual permits or a General ' Permit and has decided to issue a General Permit to cover all Phase II permitees in the state.) ' ■ Issue menu of appropriate BMPs ■ Support local programs: ■ Oversee programs ' 2-2 R. W. Beck X001159_3335 12/27/02 OVERVIEW OF NPDES PHASE II ' ■ Provide Technical Assistance ' ■ Monitoring ■ Enforcement , The proposed Federal schedule for Phase II compliance is as follows: ■ NPDES permitting authority (Washington State Department of Ecology) is ' required by the Federal rule to issue a final general permit by December 8, 2002. Although this is a requirement included in the Federal register, Ecology has informally indicated that they do not have sufficient resources to issue the general ' permit by this deadline. Ecology anticipates beginning work on the general permit in the fall or summer of 2003 and would likely not be complete until late 2004. This has created a dilemma among many municipal jurisdictions. The ' Clean Water Act requires NPDES Phase II jurisdictions to make application for a NPDES permit by March 8, 2003. There is some concern that if municipalities do ' not have a permit to apply for and obtain in accordance with the promulgated schedule, they can be subject to third party lawsuits. As a result of discussions between many cities and Ecology, with input from the American Public Works ' Association Stormwater Managers' Committee, Ecology has developed a permit application to allow NPDES Phase II jurisdictions to apply for a permit based upon the EPA model NPDES Phase II Minimum Control Measures until such ' time as Ecology develops its own permit for Washington State. The permit application would be submitted to Ecology and used to protect the local governments from liability, due to the fact that Ecology will not have the permit , and requirements available by the deadline (March 8, 2003). ■ Regulated small MS4s and stormwater discharges associated with other activities need to submit their permit applications by March 8, 2003 (or three years and 90 ' days after final regulations were issued). ■ Regulated MS4 programs must be developed and implemented five years after ' permit issuance. The exact schedule for adopting and implementing new standards and programs will likely be defined in Ecology's General Permit, when developed. . Federal Stormwater Management Requirements under NPDES Phase II 1. For MS4s ' The EPA requires, under the Phase II regulation, that all owners/operators of small MS4s reduce the discharge of pollutants from a regulated system to the "maximum extent practicable" to protect water quality (Federal Register Vol. 63, p. 1574). At a ' minimum,jurisdictions regulated under Phase II must: ■ Specify BMPs for six minimum control measures and implement them to the ' "maximum extent practicable." Maximum extent practicable is the statutory standard that establishes the level of pollutant reductions that operators of X001159_3335 12/27/02 R. W. Beck 2-3 , Section 2 ' regulated MS4s must achieve. The CWA requires that NPDES permits for discharges from MS4s "shall require controls to reduce the discharge of pollutants to the maximum extent practicable, including management practices, control techniques and system, design and engineering methods." (Federal Register/Vol. 64,No. 235/ 1999/Rules and Regulations) ' ■ Identify measurable goals for control measures. ■ Show an implementation schedule of activities or frequency of activities. ' ■ Define the entity responsible for implementation. 2. For Construction and Other Activities Construction activities that disturb one to five acres must also be regulated under an NPDES Phase II permit. Construction activities larger than 5 acres are already regulated under the Phase I program. The permit requires application of stabilization and structural best management practices to reduce the potential for erosion and the discharge of sediments from construction sites. The stabilization and structural practices cited in the permit are similar to the minimum requirements for ' sedimentation and erosion control in Volume I of the Storm Water Management Manual for Western Washington. The permit also requires construction in western Washington to select from BMPs described in Volume II of the most recent'edition of ' Ecology's Stormwater Management Manual (SWMM). The applicants are required to prepare a stormwater pollution prevention plan (SWPPP) that contains the following; ■ Erosion and Sediment Control Plan, including stabilization practices, structural practices, requirements for maintenance, recordkeeping ■ Control of Pollutants other than sediment on construction sites ■ Coordination with local requirements The NPDES permitting authority may also require that other facilities and industrial and construction activities, as well as small MS4s outside urbanized areas, be designated on a case-by-case or categorical basis. Each of these requirements is discussed in more detail in the subsections that follow. BMPs for Six Minimum Control Measures Municipal stormwater management programs must specify best management practices (BMPs) for the following six minimum control measures: 1. Public Education and Outreach on Stormwater Impacts ■ A public education program must be implemented to distribute educational ' materials to the community. ■ The community should be made aware about the impacts of stonnwater ' discharges to waterbodies and the steps needed to decrease stormwater pollution ■ Municipalities are encouraged to work with their state and Phase I ' communities to develop an education/outreach program more efficiently ' 2-4 R. W. Beck X001159_3335 12/27/02 OVERVIEW OF NPDES PHASE II 2. Public Involvement/Participation ' ■ The public must be involved in developing the municipality's stormwater program by following state, tribal and local public notice requirements. ' ■ All economic and ethnic groups should be included. ■ Examples of public involvement/participation that should be considered ' include public hearings, citizen advisory boards, and working with citizen volunteers. 3. Illicit Discharge Detection and Elimination , ■ The owner or operator of a regulated small MS4 must demonstrate awareness of their system, using maps or other existing documents. , ■ They also must develop a storm sewer system map that shows major pipes, outfalls, and topography. ' ■ A Phase II community must effectively prohibit illicit discharges into the separate storm sewer system. ■ Appropriate enforcement procedures must be implemented. ' ■ A Phase II community must develop and implement a plan to detect and address illicit discharges (including illegal dumping) to the system. , ■ Public.employees, businesses, and the general public must be informed of the hazards associated with illegal discharges and improper disposal of waste. ' 4. Construction Site Stormwater Runoff Control ■ The owner or operator of a regulated small MS4 must develop, implement, and enforce a program to reduce nonpoint source pollution from construction ' sites of more than one acre. ■ A regulatory mechanism must be used to control erosion and sediment to the ' maximum extent practicable and allowable under state, tribal or local law. ■ Existing erosion and sediment control ordinances may suffice, if approved by the NPDES permitting authority. ' 5. Post-Construction Stormwater Management in New Development and Redevelopment ' ■ Owners or operators of regulated small MS4s must develop, implement, and enforce a program that addresses stormwater runoff from new development and redevelopment projects that result in land disturbances of at least an acre ' and that discharge to their MS4. ■ Appropriate structural (capital improvement) and non-structural (regulatory, ' public education) BMPs must be used. ■ Controls must ensure that water quality impacts are minimized. ■ Adequate long-term operation and maintenance of BMPs connected to a ' regulated MS4 must be addressed. X001159_3335 12n7/02 R. W. Beck 2-5 ' Section 2 ■ The goal, at a minimum, should be to maintain pre-development runoff conditions to existing site conditions. ' ■ EPA encourages the use of preventive measures, including non-structural BMPs, which are usually thought to be more cost-effective. Ecology is using this minimum control measure as a basis for requiring ' municipalities to adopt the 2001 SWMM or equivalent manual. (See Section 3) 6. Pollution Prevention/Good Housekeeping for Municipal Operations ' ■ Owners or operators of small MS4s must develop and implement cost- effective operation and maintenance, as well as training programs, with the goal of preventing or reducing pollutant runoff from municipal operations. Measurable Goals for Control Measures The requirement allowing each permittee to identify its own measurable goals for each control measure is unique to Phase II. Examples of measurable goals include: ' ■ Inspecting or repairing a certain number of catch basins each year. ■ Conducting street-sweeping operations a certain number of times each year. ■ Inspecting municipal right-of-ways to identify illicit discharges. ■ Conducting a certain number of training classes for municipal operations each year. ■ Reporting the help of a certain number of volunteers each year to perform water quality monitoring or education/outreach activities. Implementation Schedule of Activities or Frequency of Activities Regulated communities must show an implementation schedule of activities or frequency of activities that will be done to comply with their NPDES Phase II permit. An example might include the following entries: Sweep City streets X times per year Vacuum storm drain catch basins Y times per year ' Conduct classroom stormwater education Z times per year Implement Household Hazardous Waste Program by a certain date Entity Responsible for Implementation ' Regulated communities must also indicate who is responsible for implementing, monitoring, and enforcing their NPDES Phase II permit requirements. There must be one entity responsible for the entire program. ' 2-6 R. W. Beck X001159 3335 12/27/02 OVERVIEW OF NPDES PHASE II The Phase II regulations are amenable to creative implementation strategies, as they ' encourage communities to take a watershed or cooperative approach. Communities may also be covered under a neighboring Phase I community, or allow another entity, ' such as a county, to implement certain minimum control measures or portions of minimum control measures. The regulated entity, however, is still responsible for complying with the requirements of the permit. ' Phase II Permitting Process At some point, a general permit will be issued by Department of Ecology to provide , permit coverage for all MS4s in the state. Permittees such as the City of Renton will most likely submit a Notice of Intent (NOI) to the permitting authority(Ecology) to be ' covered under a general permit. Under the federal permit process, the City would be required to identify and submit the information below, however, it is noted that Ecology may make modifications when they prepare the general permit: , ■ The BMPs that will be implemented for each of the six minimum control measures. , ■ The measurable goals for the minimum control measures. ■ The month and year in which each BMP will be started and completed or the ' frequency of action if it is ongoing. ■ The person(s) responsible for implementing or coordinating the stormwater management program. , This information could be submitted in an NOI under the general permit. The NOI form is reviewed by the permitting authority, which then prepares a draft permit. Once the draft is ready, it is sent to the applicant and published in order to notify the general public of the proposed permitting activity. The permitting authority then accepts comments on the draft permit from all interested persons. Revisions are then ' made based on comments received, and the permit is issued final. EPA is not specifying NOI requirements for operators of construction sites of less than five acres applying for coverage under a general permit. While EPA recognizes the ' benefit of NOIs—which allow for better outreach and dissemination of information— Federal regulators are sensitive to the burden being placed on the regulated community and on the NPDES regulators. Therefore, it is up to the NPDES ' permitting authority to determine whether it will require NOI submission for construction sites disturbing less than five acres. NDPES Phase II Ongoing Requirements Under the Phase II rule, regulated communities must conduct periodic evaluations and ' assessments of their stormwater management practices, maintain records, and prepare required reports according to Table 2-1. , X001159_3335 12/27/02 R. W. Beck 2-7 ' Section 2 ' Table 2-1 Minimum Reporting Requirements ' Evaluation and Assessment Requirements Record Keeping Requirements Reporting Requirements ■ Evaluate program compliance ■ Keep records required by the ■ Submit annual reports to the NPDES permitting authority for at permitting authority for the first least three years 5 year permit term ' ■ Evaluate the appropriateness of ■ Submit the records when requested ■ In subsequent 5 year terms, identified BMPs by the permitting authority submit reports in years two and four or more frequently as required ■ Evaluate progress toward ■ Make records and stormwater ■ Reports should include: achieving measurable goals management plan accessible to the ■ Status of permit condition public during regular working hours compliance ' ■ The NPDES permitting authority . A reasonable copying fee may be , Appropriateness of identified may determine monitoring charged BMPs requirements appropriate to ■ Advance notice of up to two days ' your watershed. EPA Progress toward achieving for copying may be requested goals for each encourages participation in a measurable g group monitoring project. measure ' . Results of data collected and analyzed during the reporting period . A summary of the activities that will take place during the next reporting period . Any changes in measurable goals ' NDPES Phase II and TMDLs As part of the NPDES Phase II requirements, the City will also be facing requirements ' associated with Total Maximum Daily Loading (TMDL) pollutant requirements. A TMDL is a calculation of the maximum amount of a pollutant that a waterbody can receive and still meet water quality standards, and an allocation of that amount to the ' pollutant's sources. Under section 303(d) of the 1972 Clean Water Act, Ecology is required to develop lists of impaired waters that do not meet state water quality standards. The law requires that Ecology establish priority rankings for waters on the lists and develop TMDLs. The City will be required to comply with more stringent requirements beyond the six Minimum Control Measures as identified in a TMDL. The water bodies in the City of Renton or immediately downstream of the City, which are currently on the 303(d) list include Springbrook Creek, the Green/Duwamish River, May Creek, the Cedar River and Lake Washington. These water bodies are on the 303(d) list due to water quality ' standards violations for Fecal Coliform, Temperature, Dissolved Oxygen and Metals. No TMDL's have been established yet for these water bodies, but Ecology will be ' 2-8 R. W. Beck X001159_3335 12/27/02 OVERVIEW OF NPDES PHASE II ' developing them in the near future. Ecology is currently conducting a scoping process , for developing TMDL's in WRIA 8 and 9. Summary of NPDES Phase II Requirements A summary of the requirements for jurisdictions regulated under Phase II are listed in ' Table 2-2. Table 2-2 , Summary Table of NPDES Phase II Requirements ■ Specify BMPs for six minimum control measures and implement them to the "maximum extent practical" ' ■ Identify measurable goals for control measures ■ Show an implementation schedule of activities or frequency of activities ' ■ Define the entity responsible for implementation City p De artments/Public Affected by NPDES Phase II Requirements ' Several City Departments as well as the development community will be affected by the NPDES Phase II requirements. Table 2-3 provides a preliminary listing of likely ' groups affected by the various minimum elements as well as the permit administration and implementation for the city. _ X001159_3335 12/27/02 R. W. Beck 2-9 ' Section 2 ' Table 2-3 Summary Table of City Departments/Public Affected by NPDES Phase II Requirements 1 NPDES Phase 2 Requirements City Department/Group Likely Affected Permit Administration—Development/ PBPW ' Monitoring • Development Services • Utility Systems Surface Water • Maintenance Services Minimum Control Measure#1 -Public Education PBPW ' and Outreach on Stormwater Impacts Utility Systems- Surface Water (primary) • Utility Systems—Water,Solid Waste • Maintenance Services ' Development Services Transportation Systems Finance— Utility Billing ' Community Service Department—Parks and Recreation Minimum Control Measure#2—Public PBPW Involvement/Participation Utility Systems- Surface Water (primary) ' Utility Systems—Water, Solid Waste City Council—Utilities Committee Minimum Control Measure#3—Illicit Discharge PBPW Detection and Elimination Utility Systems- Surface Water (primary) ' Utility Systems—Water,Wastewater and Solid Waste • Maintenance Services(primary) • Development Services Minimum Control Measure#4—Construction Site PBPW Stormwater Runoff Control Utility Systems- Surface Water ' (primary) Utility Systems—Water and (Note: Ecology it is expected to require the adoption Wastewater ' of standards equivalent to the standards in their 2001 Development Services (primary) Ecology Manual,as a condition of the NPDES Phase 2 Transportation permit,which have thresholds that are lower than the Maintenance Services ' federal NPDES Phase II requirements. The Ecology Community Services—Parks and ' 2-10 R. W. Beck X001159_3335 12/27/02 OVERVIEW OF NPDES PHASE II threshold for construction site stormwater runoff Facilities ' control applies to projects that create or add 2,000 square feet of impervious surfaces,or have 7,000 All Public or Private projects that involve land ' square feet of land disturbing activities. Refer to page disturbing activities(clearing and grading)>_ "1 1 of Table 3-1 for more detailed information about Ac. Ecology thresholds) All projects that involve land disturbing ' activities of> 1 acre will need to also obtain a Construction NPDES Permit. Minimum Control Measure#5—Post-Construction PBPW Stormwater Management in New Development and Utility Systems- Surface Water Redevelopment (primary) ' (Note: Ecology it is expected to require the adoption of Utility Systems—Water(Aquifer ' standards equivalent to the standards in their 2001 Protection)and Wastewater Ecology Manual, as a condition of the NPDES Phase 2 permit,which have thresholds that are lower than the Development Services(primary) ' federal NPDES Phase II requirements. The Ecology threshold for post construction stormwater management applies to projects that create or add Maintenance Services 2,000 square feet of impervious surfaces,or have ' 7,000 square feet of land disturbing activities. In Transportation Systems general,for projects adding between 2,006 and 5,000 square feet of new or replaced impervious surfaces, ' MR#1-5 apply;for projects adding>5,000 sf of new Community Services—Parks and Facilities and/or replaced impervious surfaces, MR# 1 through 10 apply. Refer to page 1 of Table 3-1 for more detailed information about Ecology thresholds) All Public and Private projects proposing new or replacement of impervious surfaces,or land disturbing activities>_ 1 Ac. Private Projects(to meet new standards and for maintenance) Minimum Control Measure#6—Pollution PBPW Prevention/Good Housekeeping for Municipal Utility Systems- Surface Water Operations (primary) , • Utility Systems—Water,Wastewater and Solid Waste • Maintenance Services(primary) ' • Transportation Systems(roads and airport) • Development Services ' Community Services(Parks, Recreation and Facilities) Fire Department , r X001159_3335 12127i02 R. W. Beck 2-11 , Section 3 EVALUATION OF STORMWATER DESIGN MANUALS This section contains a general description of the three following stormwater design ' manuals; ■ Ecology's 2001 Stormwater Management Manual for Western Washington (SWMM) ■ 1998 King County Surface Water Design Manual (KCSWDM) ■ 1990 KCSWDM (amended 1994) ' The general description is followed by a matrix evaluation (Table 3-1) comparing the minimum requirements of each manual. The power point presentation in Appendix A provides a more condensed version of the manual comparison with emphasis on Ecology's 2001 SWMM and the 1998 KCSWDM. Stormwater Management Manual for Western Washington (Ecology, 2001) The Washington Department of Ecology recently published a new guidance document entitled Stormwater Management Manual for Western Washington (SWMM). The manual replaces Ecology's 1992 Stormwater Management Manual for the Puget Sound Basin and provides guidance for municipalities in Western Washington. It provides guidance for new development and redevelopment of industrial, commercial, ' residential sites and road projects. It includes minimum requirements and Best Management Practices (BMP's) and actual requirements for projects permitted by local, state, and Federal governments. For the Puget Sound region including the City ' of Renton, local governments are required by the Puget Sound Water Quality Management Plan to adopt standards that are equivalent to the SWMM by March 2003. For municipalities subject to NPDES Phase. II stormwater requirements in Western Washington, Ecology will require the SWMM or equivalent level development regulations (although this is subject to ongoing rulemaking). The manual is arranged in five volumes contained in one notebook. ' ■ Volume I—Minimum Technical Requirements ■ Volume II— Construction Stormwater Pollution Prevention ■ Volume III—Hydrologic Analysis and Flow Control Design ■ Volume IV— Source Control Best Management Practices (BMPs) ■ Volume V—Runoff Treatment BMPs 1 X001159_3335 12/27/02 Section 3 ' The manual has seven key changes when compared to the 1992 Stormwater ' Management Manual for the Puget Sound Basin: 1. The manual applies to all of western Washington. ' 2. Thresholds for the application of BMP's are written to allow for the most appropriate sizing and placement of flow control and treatment BMP's based on ' "onsite" conditions. 3. Redevelopment projects generally have the same requirements for any new impervious surfaces as new development projects. Surfaces outside project limits ' are not subject to stormwater requirements unless they drain through the redevelopment treatment control facility. 4. New BMPs have been added for controlling erosion from construction sites and ' for preventing stormwater pollution at its source. 5. Higher levels of treatment are required in many cases to reduce the incidence of discharges that are harmful to fish and other aquatic life. 6. Flow control requirements now address matching the duration of peak flows. In ' addition, the sizing of flow control facilities is to be based on the assumption that pre-developed condition is forested, the condition prior to Euro-American settlement. The 1992 Ecology Manual referred to "existing site conditions" for ' determining pre-developed runoff. These changes result in larger retention and detention facilities. 7. A hydrologic computer model that predicts runoff for all areas of western , Washington has been developed using the Hydrologic Program — Fortran (HSPF) computer program and Ecology will be shifting to this model (WWHM) instead of the event based hydrologic analysis contained in the 1992 manual. Ecology was contacted regarding the status of the manual and whether Ecology will require the manual as a part of the pending NPDES Phase II. The follow paragraphs summarize input received from Ecology. A complete copy of the question and answers provided by Ecology is included in Appendix B. Ecology is now in the process of determining what the specific NPDES Phase II ' requirements will be. As a part of this process, Ecology is getting public input and holding public hearings. At this same time, Ecology is working with NPDES Phase I , communities (e.g., King County, Pierce County, Snohomish County, Seattle and Tacoma) to reissue their Phase I permit. As a part of the Phase I permit renewals, Ecology intends to require the Phase I municipalities to update their surface water design manuals to be equivalent to Ecology's 2001 manual. Again, that will be subject ' to public input and hearings through the permit process. 3-2 R. W. Beck X001159_3335 12/27/02 ' EVALUATION OF STORMWATER DESIGN MANUALS 1998 King County Surface Water Design Manual (KCSWDM)(King County, 1998) ' The 1998 KCSWDM was an update of the 1990 KCSWDM performed in part to comply with the NPDES Phase I permit. The organization of the 1998 manual includes six main chapters included in one notebook: ■ Chapter 1 —Drainage Review and Requirements ■ Chapter 2—Drainage Plan Submittal ■ Chapter 3 —Hydrologic Analysis and Design ' ■ Chapter 4—Conveyance System Analysis and Design ■ Chapter 5 —Flow Control Design ■ Chapter 6—Water Quality Design In addition, there are four appendices that are also contained in the notebook. ■ Appendix A — Maintenance Requirements for Privately Maintained Drainage Facilities ■ Appendix B — Master Drainage Plan Objectives, Criteria and Components and Review Process ■ Appendix C — Small Site Drainage Requirements (separately detachable ' publication for easy removal) ■ Appendix D — Erosion & Sediment Control Standards (separately detachable publication for easy removal) Major changes in the 1998 manual from the 1990 manual include: . ■ Restructured some of the chapters and appendices including; moving the previous chapter 5 (TESC standards) to the separately stand alone Appendix D, dividing the previous Chapter 4 (Hydraulic Analysis and Design) into 3 separate chapters (4, 5, and 6), and adding the new Appendix C for Small Site Drainage ' Requirements ■ Added a new drainage review threshold for applying drainage requirements to a smaller project that drains to landslide hazard areas (including a tightline requirement) ■ Added more guidance on Core Requirement No. 2 on how to identify and mitigate impacts to downstream drainage problems ■ New runoff computation methodology, KCRTS, which is a continuous simulation ' computer model based upon the Hydrologic Simulation Program Fortran (HSPF) ■ Revised flow control standards, including the requirement to match the duration of peak flows in drainage areas sensitive to erosion and increased durations ■ New water quality standards and designs ■ New area-specific standards for both flow control and water quality X001159 3335 12/27/02 R. W. Beck 3-3 Section 3 ■ New requirements for redevelopment ■ Addition of water quality source controls (through reference of separate document) ' King County is now in the process of updating the 1998 manual. The County is currently drafting revisions to the 1998 KCSWDM to make it equivalent with the 2001 Ecology SWMM. The update is occurring, in part, because according to the language of the County's existing NPDES Phase I permit, the County is required to adopt the equivalent of any updates to the 1992 Ecology Manual. The County's current plan is ' to complete a draft manual available in early 2003, when the Executive plans to submit legislation to the King County Council for the manual update. If and when the updated KCSWDM is actually adopted is difficult to estimate. The manual update is ' being done in conjunction with the County's update of their Critical Area Ordinances as required by the Growth Management Act. The County is required to update their Critical Area Ordinances by December 2004 at the latest. Appendix B contains a summary of the proposed changes to the manual to make it equivalent to the 2001 Ecology Manual. 1990 KCSWDM (amended 1994) The 1990 KCSWDM was adopted by many jurisdictions in the Puget Sound area as part of local regulations establishing drainage design standards. The latest revisions to the manual were made in 1994. King County completely replaced its 1990 Manual with the 1998 KCSWDM, as described above, and the 1990 KCSWDM is no longer in ' publication by King County. The 1990 KCSWDM sets forth seven Core requirements and 12 Special Requirements to describe the requirements and standards for designing storm drainage improvements as part of new development and ' redevelopment projects. The City of Renton currently adopts and amends the 1990 KCSWDM as parts of its drainage ordinance. Major amendments the City applies to the 1990 KCSWDM relate to (1) the City's development/permit review process, and (2) changes in the drainage requirements to provide further protection in the City's Aquifer Protection Area. 3-4 R. W. Beck X001159_3335 12/27/02 , 1 Table 3-1 City of Renton - Stormwater Manual Comparison Stormwater Management Manual for Western Washington(August 2001) 1998 King County Surface Water Design Manual 1990 King County Surface Water Design Manual Applicability and Exemptions Different combinations of minimum requirements apply depending on the type and size of the project. In The manual uses thresholds to define the type of drainage review for different sizes and types of projects. The Drainage review is required for any proposed project requiring a County permit or approval that t general,small sites are required to control erosion and apply simpler approaches to provide treatment and type of drainage review generally defines which minimum requirements apply. The manual differs from would: flow control. The Manual provides figures(Figure 2.2(new development)and Figure 2.3(redevelopment)) Ecology's in that it applies Core and Special.Requirements. Core requirements(CRs)are required for all ■ Add more than 5,000 sf of new impervious area,or that are used to determine applicability and summarize as follows: projects meeting certain thresholds. Special requirements(SRs)only apply depending on the project location or . Collect and concentrate surface and stormwater runoff from a drainage area of more than ' site specific characteristics. 5,000 sf,or New Development New Development ■ Contain,or abut,a floodplain,stream,lake,wetland or closed depression,or a sensitive area. All new development is required to comply with Minimum Requirement(MR)#2(Construction Stormwater New single-family development that adds between 2,000 to 10,000 sf of new impervious surface and clears<2 This manual differs from Ecology's in that it applies two types of County drainage requirements: ' Pollution Prevention). In addition,new development exceeding certain thresholds are required to comply acres or 35%of the site requires a Small Site Drainage Review(see Ecology's MR#5 for requirements). Core and Special Requirements. The seven Core Requirements(CRs)apply to every project,which with additional MRs as follows: Projects adding>5,000 sf (or 2,000 sf in a landslide hazard area)of impervious surface not qualifying for Small requires drainage review. The twelve Special Requirements(SRs)may apply to a project depending ■ Comply with MRs#1 through#5 if project creates or adds 2,000 sf,or greater,of new,replaced,or new Site Drainage Review requires a Full Drainage Review for which all Core and applicable Special Requirements on the nature of the project and its location. plus replaced impervious surface area,or has land disturbing activity of 7,000 sf or greater. apply. In addition to the exceptions provided for specific requirements,variances may be granted in rare • Comply with MRs#1 through#10 if project creates or adds 5,000 sf,or more,of new impervious surface Certain Small Site projects or other projects not subject to Full Drainage Review may also be subject to a cases. ' area,or converts 3/4 acres,or more,of native vegetation to lawn or landscaped areas,or converts 2.5 Targeted Drainage Review,an abbreviated evaluation,in which selected Core and Special Requirements apply Thresholds for Redevelopment are not included. Redevelopment is not defined or discussed in the acres,or more,of native vegetation to pasture. depending on site conditions. Three different categories are given. Refer to Table 1.1.2.A. Targeted Drainage 1990 manual. Reviews also apply to projects that don't add new impervious surface but rather modify the drainage system (e.g.,>12-inch size)as will as clearing/grading projects. There is also a Large Site Drainage review for projects>50 acres which requires more complex review. Redevelopment Redevelopment All redevelopment shall be required to comply with MR#2. In addition,redevelopment that exceeds certain Redevelopment projects costing>$500,000 that create>5,000 sf of continuous pollution generating surfaces thresholds shall be required to comply with additional MRs as follows. (pgs)from new and/or replace surfaces requires a Full Drainage Review. Redevelopment projects>$100,000 ■ Comply with MRs#1 through#5 for the new and replaced impervious surfaces if the new,replaced,or in a high-use site'requires a Targeted Review. total of new plus replaced impervious surfaces is 2,000 sf or more,or 7,000 sf or more of land disturbing Exemptions: activities. Many of the Core and Special requirements have their own thresholds(defined below for the various - Comply with MRs#1 through#10 for the new and replaced impervious surfaces if the project adds 5,000 requirements),which may preclude or limit their application to a project. The simplified drainage requirements sf or more of new impervious surfaces or,converts 1/4 acres,or more,of native vegetation to lawn or applied under the Small Site Drainage Review are considered sufficient to meet the overall intent of the core and landscaped areas,or converts 2.5 acres,or more,of native vegetation to pasture, special requirements(except where a Targeted Review is required)and is considered exempt from the Core and If runoff from new impervious surfaces and converted pervious surfaces is not separated from runoff from Special Requirements other surfaces on the project site,stormwater treatment facilities must be sized for the entire flow that is directed to them. The local government may allow the MRs to be met for an equivalent(flow and pollution characteristics)area within the same site. For public roads projects,the equivalent area does not have to be within the project limits,but must drain to the same receiving water. The following activities are exempt: ■ Most forest practices regulated under Title 222 WAC. ' Commercial agriculture practices(except conversion from timberland to agriculture). ■ Road maintenance practices including: pothole and square cut patching,overlaying existing asphalt or concrete pavement with asphalt or concrete without expanding the area of coverage,shoulder grading, reshaping(regrading drainage systems,crack sealing,resurfacing with in-kind material without expanding the road prism,and vegetation maintenance. • Underground utility projects that replace the ground surface with in-kind material of materials with similar runoff characteristics are only subject to MR#2,Construction Stormwater Pollution Prevention. ' Due to the unique nature of road projects,additional clarification is provided on the applicability of MRs. Refer to the manual for the entire list of specific clarifications,some of the clarifications include: ■ Removing and replacing a paved surface to base course or lower,or repairing the roadway base and if impervious surfaces are not expanded,apply MRs#1 -15. ■ Extending the pavement edge without increasing the road prism, or paving graveled shoulders are considered new impervious surfaces and subject to the MRs triggered for redevelopment thresholds. ■ Resurfacing by upgrading from dirt to gravel/asphalt, or from gravel to asphalt, etc. are considered new ' impervious surfaces and are subject to the MRs triggered for redevelopment thresholds identified for projects are met. Definition Similar to Ecology Manual X001159 3335 Table 3-1 (continued) ' City of Renton — Stormwater Manual Comparison Stormwater Management Manual for Western Washington(August 2001) 1998 King County Surface Water Design Manual 1990 King County Surface Water Design Manual MR No. 1: Preparation of Stormwater Site Plan ' The Stormwater Site Plan(SWSP)is a comprehensive report containing all of the technical information and Drainage Review Types and Plan Submittal Requirements Drainage Review Types and Plan Submittal Requirements analysis necessary for regulatory agencies to evaluate a proposed new or redevelopment project for Althoughnot specifically identified as a minimum requirement,the manual contains requirements for drainage Although not specifically identified as a minimum requirement,the manual contains requirements for ' compliance with stormwater requirements. Contents of the Stormwater Site Plan will vary depending on theP y q g g P y eq applicability of MRs. The goal of this chapter is to provide a framework for uniformity in plan preparation, Plan submittals. The submittal requirements vary depending on the type of permit or project and the type of drainage plan submittals. An engineering plan is required if: ensure property drafted engineering of tans and supporting documents,and facilitate long-term preparation, operation and drainage review. Most projects subject to Full Drainage Review will require engineering plans that include a ■ A hydrologic,geotechnical,or soils analysis is required,or P y g g P pp g g Technical Information Report(TIR),Site Improvement Plans,and an erosion and sediment control(ESC)plan. maintenance of the proposed system. The SWSP shall contain: New drainage facilities must be constructed,or existing drainage facilities modified,or ' In addition,a landscape management plan may also be required through CR#8 Water Quality. The TIR is to be 0 Site 1. Project Overview a comprehensive supplemental report containing all technical information and analysis necessary to develop the required. rictions (such as building setback lines, floodplain limits and drainage easements) are 2. Existing Conditions Summary site improvement plan and shall include the following 10 sections which are similar to Ecology's SWSP: The drainage portion of engineering plans shall consist of a Technical Information Report(TIR)and a 3. Off-site Analysis Report 1. Project Overview set of Site Improvement Plans.Less stringent requirements apply to certain individual Residential ' 4. Permanent Stormwater Control Plan(quantity and quality control design and conveyance system 2. Conditions and requirements Summary Building Permits and to Short Plats. analyses) 3. Off site Analysis 5. Special Reports and Studies(special reports and studies conducted to prepare the SWSP(e.g.soil The TIR shall be a comprehensive supplemental report containing all technical information and 4. Flow Control and Water Quality Facility Analysis and Design testing,wetlands delineation). analysis necessary to develop the Site Improvement Plans and shall contain the following eleven ' 5. Conveyance System Analysis and Design 6. Other Permits 6 Special Reports and Studies sections: . 7. Operation and Maintenance Manual 1. Project Overview 8. Bond Quantities Worksheet(if local government adopts a requirement for a performance bond for 7. Other Permits8. ESC Analysis and Design 2. Preliminary Conditions Summary construction) 9. Bond Quantities,Facility Summaries and Declaration of Covenant 3. Off-Site Analysis 9. Construction Stormwater Pollution Prevention Plan 10. Operations and Maintenance Manual. 4. ConveRetention/Detention cSyseAnalysis and Design 5. Conveyance Systems Analysis and Design The 2,000 sf threshold for impervious surfaces and 7,000 sf threshold for land disturbance are chosen to The required contents and format of the Site Improvement Plans and ESC Plan are also provided. 6. Special Reports and Studies. capture most single family home construction and their equivalent. Note that the scope of the stormwater site Small projects subject to the Targeted Drainage Review require the same submittals,except that the Site 7. Basin and Community Planning Areas ' plan only covers compliance with MRs#2 through#5 if the thresholds of 5,000 sf of impervious surface or Improvement Plans,TIR,and ESC plans may be of a more limited scope. Projects that quality for Small Site 8. Other Permits conversion of 1/4 acre of native vegetation to lawn or landscape,or conversion of 2.5 acres of native Drainage Review,may be required to submit small site drainage plans which are simplified drainage and erosion 9• Erosion/Sedimentation Control Design vegetation to pasture are not exceeded. control plans that.can be prepared by a non-engineer from a set of pre-engineered design details. Appendix C 10. Bond Quantities Worksheet,Retention/Detention Facility Summary Sheet and Sketch,and of the manual contains the specifications for small site drainage plans. Declaration of Covenant 11. Maintenance and Operations Manual The required contents and format of the Site Improvement Plans are also provided. The contents of the TIR and Site Improvement Plans include the erosion and sedimentation control plan. ' 1 X001159 3335 2 ' • O : CITY OF RENTON Office of the City Attorney g Jesse Tanner,Mayor Lawrence J.Warren RECEI VE BAN C i 2083 MEMORANDUM e1TY OF RENTON t=UBLIC WORKS AGMIN To: Gregg Zimmerman, PBPW Administrator From: Lawrence J. Warren, City Attorney Date: January 16, 2003 Please find enclosed a short article on the EPA's Phase II Storm Water Rules. This article generally discusses the NPDES Phase II permits. I am quite sure that you are familiar with the topic but thought you might appreciate a different perspective. Lawrence Warren LJW:tmj cc: Jay Covington T10.37:54 Post Office Box 626-Renton,Washington 98057-(425)255-8678/FAX(425)255-5474 R E N T O N ®This paper contains 50%recycled material,30%post consumer AHEAD OF THE CURVE INTERNATIONAL MUNICIPAL LAWYERS ASSOCIATION Work Session: Health and Environment Section Workshop Title: EPA's Phase II Storm Water Rules: A New Permit for Your City by Presenter: Angela K. Moorman Presenter's Title: Attorney Presenter's Firm: Lloyd, Gosselink, Blevins, Rochelle, Baldwin .& Townsend, P.C. Austin, Texas © 2002 International Municipal Lawyers Association. This is an informational and educational report distributed by the International Municipal Lawyers Association during its 67 th Annual Conference, October 20-23, 2002 in Denver, Colorado. IMLA assumes no responsibility for the policies or positions presented in the report or for the presentation of its contents. EPA'S PHASE II STORM WATER RULES: A NEW PERMIT FOR YOUR CITY Angela K. Moorman For the past several years, the U.S. Environmental Protection Agency's ("EPA") storm water permitting requirements have been applicable only to cities with populations of greater than 100,000 people, certain industries identified in the regulations, and construction sites of five or more acres. In 1999, EPA adopted the much anticipated Phase II storm water regulations. As adopted, the 1999 regulations almost guarantee that some provision of the storm water permitting requirements will affect your city in some manner. The following addresses the applicability of a specific part of the Phase II regulations — the requirement that regulated small municipal separate storm sewer systems ("MS4") obtain storm water permit coverage by early 2003.1 What is required of regulated small MS4s by the Phase II regulations will be discussed, as well as when the regulatory requirements become effective, important timelines, and permitting requirements. The Phase II regulations are the latest extension of a regulatory system established when the 1987 amendments to the Federal Water Pollution Control Act, better known as the Clean Water Act ("CWA"), established a two-phased, comprehensive approach to storm water permitting through the CWA's National Pollutant Discharge Elimination System ("NPDES") program.2 EPA's Phase I regulations, adopted in 1990, identified permitting requirements for: (1) large and medium MS4s;3 (2) specific categories of industrial activities; and (3) construction activities disturbing five or more acres of land. The Phase II regulations extend the NPDES permitting program to include storm water discharges from the following: Small MS4s located within urbanized areas (i.e., "regulated small MS4"), unless a waiver is granted by the permitting authority;4 Other small MS4s meeting designation criteria to be established by the permitting authority; and Any remaining MS4 that contributes substantially to the storm water pollutant loadings of a physically interconnected MS4 already subject to regulation pursuant to the NPDES program. The term "small MS4" does not include simply MS4s owned or operated by municipalities. Instead, .small MS4s include urban storm water systems owned or operated by states, political subdivisions of states (including municipalities, towns, counties, and general law districts), departments of transportation,public universities, and federal military bases. Angela Moorman is an associate with Lloyd, Gosselink, Blevins, Rochelle, Baldwin & Townsend, P.C., in Austin, Texas. A member of Lloyd, Gosselink's Water and Air& Waste Practice Groups, Ms. Moorman assists clients with various permitting and enforcement issues related to water quality, storm water, endangered species, wetlands, and municipal solid waste. She has been admitted to the bar in Texas and Oklahoma. Ms. Moorman received her law degree from the Indiana University School of Law in Bloomington, and also holds a Master of Science in Environmental Science from the Indiana University School of Public and Environmental Affairs. This paper has been prepared for informational purposes only and is not legal advice. It should not be construed as legal advice or opinion and is not a substitute for the advice of counsel. 2 Only small MS4s within "urbanized areas," as that term is defined by the U.S. Census Bureau, are automatically designated as"regulated small MS4s"by the Phase II regulations.s Unlike the Phase I regulations, the MS4 itself is regulated as opposed to the municipality. For example, a city may be located in an urbanized area, but the city is not regulated pursuant to the Phase II regulations if it does not own or operate the MS4. Another example that is common throughout Texas involves general law districts. If an MS4 located in an urbanized area is owned or operated by a general law district, that district will be required to submit the application or notice of intent ("NOI") and develop the required Storm Water Management Program ("SWMP"). The Phase II regulations also require the permitting authority to establish and utilize "designation criteria" to determine whether other MS4s, not automatically designated pursuant to the "urbanized area" definition, should be regulated. These designation criteria are to be used by the permitting authority to evaluate whether storm water discharges result in or have the potential to result in exceedances of applicable water quality standards, including impairment of designated uses or adverse habitat and biological impacts 6 While EPA did not establish specific designation criteria to be utilized by the permitting authority, it did publish a list of recommended criteria: ■ discharge to sensitive waters; ■ high growth or growth potential; ■ high population density; ■ contiguity to an urbanized area; significant contribution of pollutants to waters of the United States; and ■ ineffective control of water quality concerns by other programs.7 The regulations identify that the permitting authority is to apply designation criteria to those small MS4s located in an area with a population of at least 10,000 people and a population density of at least 1,000 people per square mile.8 The third group of regulated MS4s includes any remaining MS4 that contributes substantially to the storm water pollutant loadings of a physically interconnected MS4 already subject to regulation pursuant to the NPDES program.9 These MS4s can be designated for regulation by the permitting authority. For the small MS4 to be "physically interconnected" to a previously regulated MS4, the MS4 of one entity must be physically connected directly to the MS4 of the other entity. This includes roads with drainage systems and municipal streets. The Phase II regulations identify two waivers from the permitting requirements that may be granted by the permitting authority. The permitting authority may provide waivers from: (1) the permitting requirements of any regulated small MS4: (a) serving a jurisdiction with a population of less than 1,000; (b) not contributing substantially to the pollutant loadings of a physically interconnected MS4; and (c) if discharging to an impaired water body (as identified pursuant to section 303(d) of the CWA), not requiring storm water controls based on a total maximum daily load ("TMDL") that addresses the pollutants of concern; or (2) the permitting requirements for any regulated small MS4: (a) serving a jurisdiction with a population of between 1,000 and 10,000; (2) where the permitting authority has evaluated all waters that receive a discharge from the MS4; (3) where storm water controls are not needed based on a TMDL or an equivalent analysis that determines 3 sources and allocations for the pollutant(s) of concern for those waters; and (4) where future discharges from the MS4 are evaluated.10 Storm Water Management Program Requirements The Phase II regulations require each regulated small MS4 to develop and implement a SWMP that reduces the discharge of pollutants from the MS4 to the "maximum extent practicable" ("MEP"). The SWMP is to address six minimum control measures: (1) public education and outreach on storm water impacts; (2) public involvement/participation; (3) illicit discharge detection and elimination; (4) construction site storm water runoff control; (5) post-construction storm water management in new development and redevelopment; and (6) pollution prevention/good housekeeping for municipal operations.' EPA's regulations contemplate that the permitting authority will issue a general permit to provide permit coverage to regulated small MS4s. If a general pen-nit is adopted, a regulated small MS4 will be required to submit a NOI to obtain coverage pursuant to the general permit. The small MS4 is to submit a description of the best management practices ("BMPs") to be implemented and the measurable goals for each of the six minimum control measures. Public Education and Outreach on Storm Water Impacts The Phase II regulations require the operator of a regulated small MS4 to implement a public education program to "distribute educational materials to the community or conduct equivalent outreach activities" regarding the impacts of storm water on water quality.12 The purpose of the public education program is to inform the public about steps that can be taken to reduce storm water pollution. Such steps can include the use and proper disposal of fertilizers and pesticides and properly disposing of motor oil. EPA has encouraged small MS4s to tailor the public education program to the local audience and has also encouraged that educational materials be aimed at targeted commercial and industrial entities. Example measurable goals for this minimum control measure include: the number of brochures provided to citizens; the number of volunteer educators trained; and the number- of presentations made to classes at local schools. Public Involvement/Participation The SWMP must comply with applicable state and local public notice requirements. The Phase II regulations recommend a public participation process that includes efforts to engage all economic and ethnic groups.13 EPA has also encouraged MS4s to seek public participation before the NOI is submitted. This early participation is designed to encourage public participation in the development of BMPs and measurable goals. EPA believes that public participation and an involved community will result in: (1) broader public support; (2) shorter implementation schedules; (3) a broader base of expertise and certain economic benefits resulting from that base of expertise; and (4) a conduit to other water-related programs. Example measurable goals associated with this minimum control measure 4 include: storm drain stenciling; "Adopt a Storm Drain" programs; and the methods through which notice of significant events will be provided to the community. Illicit Discharge Detection and Elimination The Phase II regulations require regulated small MS4s to develop, implement, and enforce an illicit discharge detection and elimination program. The term illicit discharge is defined as "any discharge to a . . . [MS4] that is not composed entirely of storm water except discharges pursuant to a NPDES permit (other than the NPDES Permit for discharges from the . . . [MS41) and discharges resulting from fire fighting activities."14 Illicit discharges include discharges such as sanitary wastewater, improper disposal of oil, and spills from roadway accidents. The regulations state that the Phase II small MS4 permit will require the operator to: (1) develop a storm sewer system map showing the location of all outfalls, and names and location of all waters of the United States that receive discharges from those outfalls; (2) effectively prohibit through ordinance, or other regulatory mechanism, illicit discharges into the MS4 and implement appropriate enforcement procedures and actions as needed; (3) develop and implement a plan to detect and address illicit discharges to the system; and (4) inform public employees, businesses, and the general public of hazards associated with illegal discharges and improper disposal of waste.15 Example measurable goals include deadlines for the completion of the storm sewer system map, for the review of current city regulatory mechanisms, and for the adoption of any needed new provisions. A MS4 could also establish measurable goals related to the process of identifying illicit discharges into the MS4, e.g., number of inspections, establishing a process to track discharges. Construction Site Storm Water Runoff Control Operators of regulated small MS4s are required to develop, implement, and enforce a pollutant control program to reduce pollutants in storm water runoff from construction activities that result in the disturbance of one or more acres. Construction on less than one acre must be regulated if it is part of a larger common plan of development or sale that would, as a whole, disturb one or more acres of land. The regulations require that the SWMP include the development and implementation of: (A) An ordinance or other regulatory mechanism to require erosion and sediment controls, as well as sanctions to ensure compliance, to the extent allowable under State, Tribal, or local law; (B) Requirements for construction site operators to implement appropriate erosion and sediment control best management practices; (C) Requirements for construction site operators to control waste such as discarded materials, concrete truck washout, chemicals, litter, and sanitary waste at the construction site that may cause adverse impacts to water quality; (D) Procedures for site plan review which incorporate consideration of potential water quality impacts; (E) Procedures for receipt and consideration of information submitted by the public; and (F) Procedures for site inspection and enforcement of control measures.16 5 EPA recommends that the operator of a regulated small MS4 adopt an ordinance or other regulatory mechanism that provides the authority to require appropriate BMPs on construction sites,to review site plans, to conduct inspections, and to take necessary enforcement actions. Post-construction Storm Water Management in New Development and Redevelopment For this minimum control measure, the Phase Il regulations require the regulated small MS4 to develop SWMP elements that address storm water runoff into the MS4 from new development and redevelopment17 projects that disturb one or more acres of land, including projects of less than one acre that are part of a larger common plan of development or sale. The MS4 is to: (1) develop and implement strategies which include a combination of structural18 and/or non-structural19 BMPs appropriate for the community; (2) use an ordinance, or other regulatory mechanism, to address post-construction runoff from new development and redevelopment projects to the extent allowable under State or local law; (3) ensure adequate long-term operation and maintenance of BMPs; and (4) ensure that controls are in place that would minimize water quality impacts.20 Pollution Prevention/Good Housekeeping for Municipal Operations This minimum control measure requires operators of regulated small MS4s to develop and implement an operation and maintenance program that includes a training component. The purpose of such a program is to prevent or reduce storm water runoff from municipal operations.21 The training must address methods to prevent and reduce storm water discharges resulting from park and open space maintenance, fleet and building maintenance, new construction and land disturbance, and storm water system maintenance. Example measurable goals include the number of employees who receive training, the completion of new or the review of existing required Storm Water Pollution Prevention Plans ("SWPPPs") for regulated industrial activities owned or operated by the MS4, and the implementation of a recycling program. The Phase II regulations have put in place a new and complicated regulatory program. The implementation of this program over the next several months at EPA, appropriate state agencies, and regulated small MS4s will be a strenuous process for all involved. But one thing is clear, because of the breadth of the Phase II regulatory program, it is almost guaranteed to be coming, in some form,to a city near you. It should be noted that the Phase H regulations also create new permitting requirements for other entities. Small construction sites(equal to or greater than one acre)will have to obtain permit coverage for the first time. In addition, the Phase II regulations extend the compliance deadline adopted as part of the Intermodal Surface Transportation Efficiency Act of 1991 ("ISTEA") for certain Phase I industrial activities operated by municipalities with populations of less than 100,000 people. Municipalities will have to submit a Notice of Intent to obtain permit coverage pursuant to the Multi-Sector General Permit (or the equivalent state-issued industrial general permit) for municipally operated industrial activities by March 10, 2003. See 33 U.S.C.A. § 1342(p)(West 2001). 6 3 Large MS4s are those serving a population of 250,000 or greater,and medium MS4s are those serving a population of 100,000 to 250,000,as determined by the 1990 Decennial Census. See 40 C.F.R. § 122.26(b)(4)(i),(b)(7)(i)(2001). 4 The Phase II regulations repeatedly refer to the term"permitting authority." In states where EPA has not delegated the NPDES permitting program, EPA is the permitting authority. In states where NPDES authority for storm water permitting has been delegated, the permitting authority is the appropriate state agency. For example, the permitting authority in Texas is the Texas Commission on Environmental Quality due to the 1998 delegation of the NPDES program to the State of Texas. 5 The term "urbanized area" is defined by the Census Bureau after each decennial census. The Phase H regulations utilize the following definition,which was based on the 1990 Decennial Census: "an urbanized area(UA)comprises a place and the adjacent densely settled surrounding territory that together have a minimum population of 50,000 people." 64 Fed. Reg. 68,722, 68,751 (Dec. 8, 1999). For information on the Census Bureau's definition of the term "urbanized area"based on the 2000 Decennial Census,see 67 Fed.Reg. 11,663, 11,667(Mar. 15,2002). 6 See 40 C.F.R § 123.35(b);see also 64 Fed.Reg.at 68,744. 7 See 64 Fed.Reg.at 68,744. 8 See 40 C.F.R. § 123.35(b)(2). The 10,000 population/1,000 population density requirement is not a hard and fast rule, but instead is a threshold established by EPA. The permitting authority can designate any small MS4. 9 See id. § 123.35(b)(4). 10 See id. §§ 122.32(d)&(e), 123.35(d)(1)&(2). " See id. § 12234(b). In the preamble to the adopted Phase 11 regulations,EPA stated: "Compliance with the conditions of the general permit and the series of steps associated with identification and implementation of the minimum control measures will satisfy the MEP standard." 64 Fed.Reg.at 68,754. 'Z See 40 C.F.R. § 122.34(b)(1)(i). 13 See id. § 122.34(b)(2)(ii). 14 Id. § 122.26(b)(2). 15 See id. § 122.34(b)(3)(ii). 16 Id. § 122.34(b)(4)(ii)(A)-(F). 17 EPA has explained that it intends the term"redevelopment"to refer to: alterations of a property that change the"footprint"of a site or building in such a way that results in the disturbance of equal to or greater than 1 acre of land. The term is not intended to include such activities as exterior remodeling, which would not be expected to cause adverse storm water quality impacts and offer no new opportunity for storm water controls. 64 Fed.Reg.at 68,760. '$ Structural BMPs include structural practices,infiltration practices, and vegetative practices. See Office of Water,U.S. Envtl. Prot. Agency, "Storm Water Phase II Final Rule: Post-Construction Runoff Control Minimum Control Measure,"Fact Sheet 2.7(Jan.2000). 19 Non-structural BMPs include planning and procedures e. requirements for Master Plans zoning ordinances or site- based P ( g•. g ) based local controls(e.g., preservation of open space in the form of riparian zones or buffer areas). See id. 20 See 40 C.F.R. § 122.34(b)(5)(ii). 21 See id. § 122.34(b)(6)(i). 7 ' Table 3-1 (continued) City of Renton — Stormwater Manual Comparison Stormwater Management Manual for Western Washington(August 2001) 1998 King County Surface Water Design Manual 1990 King County Surface Water Design Manual 1 MR No.2: Construction Stormwater Pollution Prevention(SWPP) ' Threshold: All new development and redevelopment shall comply with Construction SWPP Elements#1 The comparable requirement in the manual is Core Requirement#5 Temporary Erosion and Sediment The comparable requirement in the manual is Core Requirement No.5 Temporary Erosion and through#12(intended to minimize the potential for construction stormwater pollution). Projects in which the Control. Sediment Control. new,replaced,or new plus replaced impervious surfaces total 2,000 sf or more,or disturb 7,000 sf or more of Threshold: Erosion and sediment control is required for all drainage reviews including Small Site Drainage Threshold: Al projects that require engineered drainage plans(see thresholds under MR#1 above) land must prepare a construction SWPP Plan(SWPPP)as part of the Stormwater Site Plan. Projects not Review(includes single-family residences). must provide Temporary Erosion and Sediment Control(TESC)measures that minimize the transport meeting this threshold are not required to prepare a Construction SWPPP,but must consider all of the twelve' of sediment to drainage facilities,water resources,and adjacent properties. Single family residences elements that pertain to the project site. A brief summary of the 12 Elements are as follows: Under the Small Site Drainage Review,the erosion control requirements are simplified and include rock not meeting the thresholds are not required to provide TESC measures. construction entrance,mulching,minimized clearing,silt fencing,and winter stabilization. Mulching is required Element 1: Mark Clearing Limits as a temporary cover to the same standards of larger projects(given below). The requirements are specified in Eleven minimum TESC requirements are defined and to control erosion and sedimentation during ' Element 2: Establish Construction Access Appendix C of the Manual. construction and to permanently stabilize soil exposed during construction. Erosion and Element 3: Control Flow Rates For larger projects,minimum ESC measures are defined as well as implementation requirements. In addition sedimentation control is to be achieved by a combination of structural control measures,cover Element 4: Install Sediment Controls ESC performances standards are defined. These are described as follows: measures,and construction practices. Element 5: Stabilize Soils(From October 1 through April 30,no soils shall remain exposed and unworked for ESC Measures A brief summary of the minimum requirements include: ' more than 2 days. From May 1 to September 30,no soils shall remain exposed and unworked Clearing Limits: Flag clearing limits prior to any site clearing. Clearing Limits: Flag clearing limits prior to any site clearing for more than 7 days). Example practices include seeding,sodding,mulching,plastic covering, and polyacrylamide(PAM). Cover Measures: Temporary cover shall be installed with the same timing restrictions as Ecology. The manual Cover Measures: Temporary cover shall be installed similar to Ecology,except the wet season is defined as one month shorter(from October 1 to March 31). This manual has the same 12 hour Element 6: P.rotect Slopes(e.g.,design and construct cut and fill slopes to minimize erosion,and divert has additional requirements that go beyond Ecology's,including;any area to remain unworked for more than 30 ' upslope run-on drainage with interceptors at top of slope). days shall be seeded or sodded;and,during the wet season,slopes and stockpiles 3H:1 V or steeper with more restriction for steep slopes as the County manual of vertical relief shall be covered if they are to during the wet season,slopes an stockpiles 3H:1 V or steeper and with more than 10 feet of v Element 7: Protect Drain Inlets than 10 feet of vertical relief shall be covered if they are to remain unworked for more than 12 hours. with remain unworked for more than 12 hours. Element 8: Stabilize Channels and Outlets Perimeter Protection: When necessary,perimeter protection to filter sediment from sheet flow shall be Element 9: Control Pollutants(e.g.,proper handling of pollutants,including waste materials and demolition provided downstream of all disturbed areas. Perimeter protection includes vegetated strips and silt fences. Perimeter Protection: similar to the 1998 manual ' debris;cover and containment of chemicals,liquid products,petroleum products,and spill Traffic Area Stabilization: prevention during maintenance and repair of heavy equipment such as drip pans). Traffic Area Stabilization: Unsurfaced entrances,roads,and parking areas used by construction traffic shall P 9 P vYp P )• be stabilized to minimize erosion and tracking of sediment offsite Sediment Retention: Element 10: Control De-Watering(e.g.,de-watering water shall be controlled and treated unless it is clean ' and non-turbid). Sediment Retention: Surface water from disturbed areas shall be routed through a sediment pond or trap. Surface Water Controls: Element 11: Maintain BMPs Surface Water Controls: Surface water controls include both intercepting surface water from disturbed areas Dust Control: Element 12: Manage the Project. This element includes several important requirements as follows: and conveying it to a sediment pond or trap as well as intercepting upstream surface water that drain onto Wet Season Construction: Similar to the 1998 manual except that the wet season is defined as disturbed areas and routing around disturbed areas. October 1 to March 31. ' Phasing Construction—phase construction to minimize the transport of sediment;permit clearing and Dust Control: Preventative measures to minimize wind transport of soil shall be implemented when a traffic grading activities for developments only if conducted pursuant to an approved site development Ian that Construction with Sensitive Areas and Buffers: Similar to the 1998 manual. 9 9 P Y P PP P P hazard may be created or when sediment transported by wind is likely to be deposited in water resources. establishes clearing/grading limits? when establishing permitted areas of clearing activities,consideration Implementation Requirements: Maintenance: Similar to the 1998 manual. ' should be given to minimizing removal of existing trees and minimizing disturbance/compaction of native Final Stabilization: Similar to the 1998 manual. soils ESC Plan: This is the requirement for the submittal of the ESC plan. The ESC plan shall include a detailed • Seasonal Work Limitations-From October 1 through April 30,clearing activities shall only be permitted if it construction sequence and shall identify required ESC measures. can be shown that silt-laden runoff will be prevented from leaving the site Wet Season Construction: Special TESC provisions are required for wet season construction(defined as ' • Inspection and Monitoring-A Certified Professional in Erosion and Sediment Control shall be identified October 1 to April 30). The requirements reference the more restrictive cover controls,requiring as much of the and shall be on-site or on-call at all times. disturbed area as possible to be covered with mulch and seed during the first week in October,and other ■ All BMPs shall be inspected,maintained and repaired as needed. requirements. Construction with Sensitive Areas and Buffers: This include special provisions for working on or within a stream or associated buffer,within a Class 1 or 2 wetland or associated buffer, or within 50 feet of a lake. An example is to phase the project whenever possible so that construction in these areas is limited to the dry season. ' Maintenance: Maintenance of TESC measures is required. In addition, it requires the applicant to designate an ESC supervisor who shall be responsible for maintenance and review of TESC measures. Final Stabilization: Prior to obtaining final construction approval, the site shall be stabilized, structural ESC ' measures(such as silt fences and sediment traps)shall be removed,and drainage facilities shall be cleaned. ESC Performance The manual also establishes performance standards that can be inspected during construction. If a sieve test ' indicated that sand-sized sediment(larger than#200 sieve)is leaving the site,then additional measures are required. Also,if is determined that a construction site poses a hazard to adjacent property or may adversely impact drainage facilities or water resources,then additional measures are required. 1 X001159 3335 3 Table 3-1 (continued) ' City of Renton — Stormwater Manual Comparison 1 Stormwater Management Manual for Western Washington(August 2001) 1998 King County Surface Water Design Manual 1990 King County Surface Water Design Manual MR#3: Source Control of Pollution Threshold: Applies to all projects. The comparable requirement in the manual is Special Requirement#4 Source Control. There is no comparable requirement in this manual. ' The intention of source control BMPs is to prevent stormwater from coming in contact with pollutants. Threshold: All commercial,industrial,multi-family projects including redevelopment(no size threshold)are Source control BMPs include operational BMPs and structural source control BMPs. Examples of required to provide water quality source controls in accordance with a referenced document,the 1995 operational BMPs include the formation of a pollution prevention team,good housekeeping practices, King County Stormwater Pollution Control Manual,and fling County Code 9.12. preventive maintenance procedures,spill prevention and cleanup,employee training,inspections of pollutant ' The Stormwater Pollution Control Manual is organized into 6 chapters. Chapter 1 describes what is expected of sources,and record keeping. Examples of structural source control BMPs include enclosing and/or covering the pollutant source(e.g.within a building or other enclosure,a roof over storage and working areas, business owners;Chapter 2 provides general information on how non-point source pollution is a problem, temporary tarp,etc.),and physically segregating the pollutant source to prevent run-on of uncontaminated Chapter 3 describes stormwater BMPs that are required for various business and nonresidential activities, stormwater. Chapter 4 provides detailed information on how to implement BMPs;Chapter 5 provides information on ' The purpose of this volume is to provide guidance for selecting BMPs to meet the MR that"all known, regulations from other agencies that could also apply to projects;Chapter 6 provides information on other programs or services that can provide assistance in implementing BMPs. available,and reasonable source control BMPs shall be applied to all projects". Users are referred to a listing(Appendix IV-A)of business types(based on the Standard Industrial The Stormwater Pollution Control Manual includes requirements that affect both design(structural)and operation ' Classifications)to identify pollutant-generating sources. Users are then referred to Chapter IV.2 to identify (non-structural)of the site. For example,car wash pads or dumpster area roofing could be required as a part of source-control BMPs for a given type of pollutant source,such as fueling stations,railroad yards,storage site design. Examples of non-structural source control measure include covering storage piles with plastic and and transfer of materials,etc. Source control BMPs are divided into"applicable"(mandatory)and isolating areas where pollutants are used or stored. "recommended." Applicable BMPs must be included in local government manuals to be considered It is noted that the County may also require mandatory source controls for existing development at any time ' equivalent. Ecology expects local governments to require those BMPs described as applicable at new through formal code enforcement if complaints or studies reveal water quality violations or problems. developments and redevelopment sites. Recommended BMPs are not expected to be mandatory,but are offered as approaches that go beyond or complement the minimum applicable BMPs. Examples of"applicable"(mandatory)operation source control BMPs include: t ■ Formation of a Pollution Prevention Team that includes assignments of responsibilities for pollution control such as inspection,operation and maintenance,and emergency response as well as training in these procedures t • Good Housekeeping practices such as sweeping paved material handling and storage areas regularly rather than washing areas that drain to the storm system,cleaning oils;debris,etc.from BMP systems regularly(such as catch basins and oiVwater separators),and repair of leaking connections,pipes hoses, valves,etc. ' • Preventive Maintenance,such as Cleaning up pollutant liquid leaks and spills in impervious uncovered areas at the end of each day,for storage of solid waste contaminated with liquids or other pollutants,use dumpsters,garbage cans,drums that are durable,corrosion resistant,non-leaking,and equipped with a ' solid cover or,in a covered area,a screen to prevent litter ■ Spill Prevention and Cleanup,such as immediately upon discovery,stop,contain,and clean up spills, and having spill containment kits available on site Examples of"recommended"operation source control BMPs include: ' ■ Recycle materials,such as oils,solvents,and wood waste to maximum extent possible ■ Where feasible,store potential stormwater pollutant materials inside a building or under a cover an/or containment. ■ Minimize use of toxic cleaning solvents,such as chlorinated solvents ' ■ Stencil wanting signs at stormwater inlets,e.g.,"Dump no Waste" Examples of"applicable"(mandatory)structural source control BMPs include: ■ For fueling stations,design fueling island to control spills and to treat collected stormwater ' ■ For loading and unloading areas for liquid or solid material,conduct unloading or loading in a manufacturing building or under a roof consistent with Uniform Fire Code to extent possible,also berm, dike and/or slope loading area to prevent run-on and the loss of spilled material from that area • For storage of liquid,food waste,or dangerous waste containers, keep containers inside a building or t store in a designated area which is covered,bermed or diked and impervious in order to contain leaks Examples of"recommended"structural source control BMPs include: ■ For loading and unloading areas for liquid or solid material,for an area that cannot contain a spill,install a an automatic shutoff system • For deicing operations at airports,install a de/anti-icing chemical recovery system 1 X001159_3335 4 ' Table 3-1 (continued) City of Renton — Stormwater Manual Comparison ' Stormwater Management Manual for Western Washington(August 2001) 1998 King County Surface Water Design Manual 1990 King County Surface Water Design Manual MR#4: Preservation of Natural Drainage Systems and Outfalls ' Natural drainage patterns shall be maintained,and discharges from the project site shall occur at the natural The comparable requirement in the manual is CR#1 Discharge at the Natural Location. The comparable requirement in the manual is Core Requirement No.1 Discharge at the Natural location,to the maximum extent practicable. The manner by which runoff is discharged from the project site Location. t not c must cause a significant adverse impact to downstream receiving waters and downgradient properties. The general requirement is very similar to Ecology's Manual. The requirements where no conveyance require energy dissipation. downstream exists at the adjacent downgradient property are the same. The general requirement is similar to Ecology's manual. The requirements where no conveyance All not ' downstream exists at the adjacent downgradient property are slightly different. These requirements Special requirements are provided where no conveyance system exists at the adjacent downgradient An additional provision,not included in Ecology's Manual,deals with landslide hazard areas. For projects located within a Landslide Hazard Drainage Area (referring to the designated Landslide maps contained within are as follows: property. These requirement include the following: g g g P If the 100- peak discharge is less than or equal to 0.2 cfs under developed conditions,then the the manual)that drain over the erodible soils with slopes steeper than 15%,a tightline system must be 1. The runoff must be conveyed across the downstream properties to an acceptable discharge point a ear y P g p' provided through the landslide hazard area to an acceptable discharge point unless one of the following with drainage easements secured from the downstream owners,or concentrated runoff may be discharged onto a rock pad or to other dispersal system. 2. The runoff must be discharged onto a rock pad shaped in a manner so as to disperse flow if the b If the 100 ear peak discharge is less than or equal to 0.5 cfs under developed conditions,then the exceptions applies; ) y g P Less than 2,000 sf of new impervious surface will be added, peak runoff rate for the 100-year,24-hour design storm event is less than 0.2 cfs for existing site concentrated runoff may be discharged through a dispersal trench or other dispersal system,provided the P conditions,or applicant can demonstrate that there will be no significant adverse impact. ■ All runoff will be infiltrated up to the 100-year event, The runoff must be conveyed to a dispersal trench or other infiltration system if the peak runoff rate for c) If the 100-year peak discharge is greater than 0.5 cfs,then a conveyance system must be provided to • The developed runoff volume is less than 50%of the existing runoff.volume from other areas draining to the 100 year,24 hour design storm event is less than 0.5 cfs for existing conditions,provided the ' convey the concentrated runoff across the downstream properties to an acceptable discharge. the location where runoff enters the landslide hazard area onto slopes steeper than 15%or, applicant can demonstrate that there will be no significant adverse impact to the downhill property. ■ The County determines that a tightline system is not physically feasible or will create a significant adverse impact based on a soils report by a geotechnical engineer. ' Also,for projects adjacent to or containing SAO-defined landslide,steep slope,or erosion hazard areas,the applicant must demonstrate that onsite drainage facilities and/or flow control BMPs will not create a significant adverse impact to downhill properties or drainage systems. 1 ' X001159_3335 5 Table 3-1 (continued) ' City of Renton — Stormwater Manual Comparison Stormwater Management Manual for Western Washington(August 2001) 1998 King County Surface Water Design Manual 1990 King County Surface Water Design Manual ' 2.5.5 MR#5: On-site Stormwater Management Projects meeting the threshold(see Applicability and Exemptions)shall employ On-Site Stormwater The comparable minimum requirement in thelGng County Manual is the requirement for residential dwellings There is no comparable requirement in this manual. However,under Core Requirement No.4,there Management BMPs to infiltrate,disperse,and retain stormwater runoff onsite to the maximum extent feasible and smaller developments to comply with the requirements of the Small Site Drainage Review. Small Site are provisions to require downspout dispersion systems for lots larger than 22,000 sf in new plats and without causing flooding or erosion impacts. The objective is to use inexpensive practices on individual Drainage Review is a simplified alternative to Full Drainage Review for small residential building and subdivision subdivisions. Downspout dispersion is allowed on residential lots less than 22,000 sf where the properties to reduce the amount of disruption of the natural hydrologic characteristics of the site. Two projects adding less than 10,000 square feet of new impervious surface and restricting site clearing to less than overflow can travel over at least 25 feet of vegetated area before leaving the property and does not primary methods are required;Roof Downspout Control BMPs(standards provided in Chapter 3 of Volume 2 acres or less than 35%of the site. The core and special requirements are replaced with simplified small site pose a flooding or erosion problem. ' III)and Dispersion and Soil Quality BMPs(standards provided in Chapter 5.3.1 of Volume V). A brief requirements that can be applied by a non-engineer. These design requirements are detailed in an Appendix C summary of these BMPs is provided below. to the Manual,entitled Small Site Drainage Requirements,includes flow controls and simple erosion and Roof Downspout Controls. Roof downspout controls are simple pre-engineered designs for infiltrating and/or sediment control(ESC)BMPs. Formal water quality treatment is not necessary. dispersing runoff from areas for the purpose of increasing groundwater recharge and reduction of runoff Flow control BMPs listed for the Small Site Drainage Review include;open space retention on larger lots, , volumes. Downspout infiltration systems are trench or drywell designs intended only for use in infiltrating dispersion,infiltration,and perforated pipe systems. The type of system used depends on the lot size,soil type, from roof downspout drains and not to infiltrate runoff from pollutant-generating surfaces. Downspout setback requirements,and topography. The open space requirement is required for small site projects over 2 dispersion systems are splash blocks or gravel-filled trenches,which serve to spread roof runoff over acres. Dispersion or infiltration BMPs are required for smaller sites,unless the site is smaller than 22,000 sf vegetated pervious areas. Dispersion attenuates peak flows,allows for some infiltration,and provides some and soils are not suitable. The requirements for dispersion and infiltration are generally similar to Ecology's. If ' water quality benefit. soils are not suitable,the site may be connected to the project's storm drainage system with a perforated Downspout infiltration should be used in soils that readily infiltrate(coarse sands and cobbles to medium tightline connection. sands). Dispersion BMPs should be used for urban lots located in less permeable soils,where infiltration is There is no requirement comparable to Ecology's that disturbed soils be amended to increase recharge. not feasible. Where dispersion too is not feasible because of very small lot size,or where there is a potential ' for creating drainage problems on adjacent lots,downspouts should be connected to the street storm drain As noted previously,Targeted Drainage Review may be required for small sites that contain sensitive areas system,which directs runoff to a project facility. Specific criteria for both selection and sizing criteria are (streams,lakes,wetlands,steep slopes,landslide hazard,erosion hazard,and channel hazard areas. (See provided. Downspout dispersion is required on all subdivision single family lots that meet one of the Applicability above.) following criteria: 1) Lots greater than 22,000 sf where downspout infiltration is not provided,or 2) Lots smaller than 22,000 sf where soils are not suitable for downspout infiltration and where the design criteria for dispersion can be met.It is also noted that the project receives a credit for roof downspout controls in terms of sizing the project quantity control,such that the project's quantity control facility can be smaller. Dispersion and Soil Quality BMPs. These BMPs include Downspout Dispersion,concentrated flow , dispersion,sheet flow dispersion,and post-construction soil quality and depth. Concentrated flow dispersion involves routing concentrated flows from driveways or other pavement through a vegetated pervious area. Sheet flow dispersion is the simplest method of runoff control and involves grading any impervious or ' pervious surface area so as to avoid concentrating flows and alternating disperse flows through a narrow band of adjacent vegetation for effective attenuation and treatment. Post-construction soil quality and depth is required in those areas disturbed by clearing/grading operations and not planned for impervious surfaces. It involves removal,stockpile,and possibly amending of native soils to increase recharge and reduce runoff , volumes. Although not required,consideration of additional BMPs is encouraged because Roof Downspout Control BMPs and Dispersion and Soil Quality BMPs do not fully mitigate the hydrologic impacts of development. t These encouraged BMPs include other low impact development"techniques such as preserving natural vegetation,full dispersion,vegetated rooftops,soil compaction protection,and porous pavement(chapters 5.3.2 through 5.3.4) X001159 3335 6 , Table 3-1 (continued) City of Renton —Stormwater Manual Comparison Stormwater Management Manual for Western Washington(August 2001) 1998 King County Surface Water Design Manual 1990 King County Surface Water Design Manual 2.5.6 MR#6: Runoff Treatment Thresholds: The following threshold clarifies when runoff treatment is required: The comparable requirement in the manual is Core Requirement#8 Water The comparable requirement in the manual is Core Requirement No.3 Runoff ■ Projects in which the total of effective,pollution-generating impervious surface(PGIS—see definition below)is 5,000 square feet or more in a Quality. Control. threshold discharge area of the project,or This CR is new from the 1990 manual and defines the required water quality Although Special Requirement No.5,Special Water Quality Controls,and Special ■ Projects in which the total of pollution-generating pervious surfaces(PGPS)is three-quarters(3/4)of an acre or more in a threshold discharge area, treatment facilities to meet one of four area-specific treatment goals,depending on Requirement No.6 Coalescing Plate Oil/Water Separators may apply to larger and from which there is a surface discharge in a natural or man-made conveyance system from the site. project type and location. A water quality treatment facility menu is provided and the projects and require more extensive treatment. Volume V of the manual is referenced and provides detailed guidance on selection,design,and maintenance of treatment facilities. The volume designer selects an appropriate design meeting the area-specific treatment goal. The CR#3,Runoff Control: Water quality treatment with a bioswale is required for includes performance goals for Basic,Enhanced,Phosphorus,and Oil Control treatment,and a menu of facility options for each treatment type. The water quality menu is intended to add flexibility to development,and includes such projects creating 5,000 sf of new impervious surface subject to vehicular use or water quality design storm volume and flow rates are intended to capture and effectively treat about 90-95%of the annual runoff volume. Treatment facilities as swales,filter strips,sand filters,wet ponds,combined quantity/quality wet storage of chemicals. facilities applied consistent with this manual are presumed to meet the requirement of state law to provide all known available and reasonable methods ponds levels,constructed wetlands,and wetvaults. The area specific requirements of treatment. and corresponding treatment levels are; Water quality swales shall be designed based on the 2-year,24-hour design storm for Design Standards: Water Quality Design Storm Volume: Facilities designed to treat a volume(wetpool)are sized based on a 6-month 24-hour storm. ■ Basic WQ Menu: 80%TSS removal—applied wherever a basic level of treatment developed conditions with maximum design depth of 0.25 foot and minimum of 200 ft Facilities designed to treat a peak rate of flow are: is sufficient. Note that all redevelopment projects need only apply this standard. for each 5 acres of impervious surface subject to vehicular use or storage of ■ Preceding Detention Facilities or when Detention Facilities are not required: The flow rate at or below which 91%of the runoff volume,as estimated • Sensitive Lake Protection Menu—50%Total Phosphorus(TP)removal—applied chemicals in the tributary basin.Runoff above the peak 2-year,24-hour design storm to areas drainage to lakes that are sensitive to phosphorus event must bypass the water quality swale. by an approved continuous runoff model will be treated. ' ■ Downstream of Detention Facilities: The full 2-year release rate from the detention facility. Resource Stream Protection Menu: 50% Zinc (Zn) removal — applied to areas drainage to"regionally significant"stream reaches SR#5,Special Water Quality Controls: This requirement applies to any proposed That portion of any development project in which the above PGIS or PGPS thresholds are not exceeded in a threshold discharge area shall apply On- . Sphagnum Bog Protection Menu: pH and nitrogen control - applied to areas project that will construct more than 1 acre of impervious surface that will be subject to site Stormwater Management BMPs MR#5. draining to sphagnum bog wetlands,(Refer to MR#8 under King County's manual vehicular use or storage of chemicals,and Volume V.2 includes Figure 2-1 that guides the selection of various treatment facilities through a step-by-step process based on the site's physical for a brief explanation of these types of wetlands). factors and the pollutants of concern. Table 2.1 summarizes the pollutants of concern and those land uses likely to generate pollutants. It also Exemptions: There are five possible exemptions: 1. Proposes direct discharge of runoff to a regional facility,receiving water,lake, ' provides suggested basic and enhanced treatment options for each land use. Follows is a brief overview of the selection process: wetland,or closed depression without on-site peak rate runoff control,or Step 1—Determine receiving waters and pollutants of concern based on off-site analysis. 1. Surface Area Exemption for projects with; <5,000 sf of new PGIS: <5,000 sf of 2. The runoff from the project will discharge into a Type 1 or 2 stream,or Type 1 Step 2—Determine if Oil Control facility required(required for high use sites,e.g.,commercial/industrial site with>100 average daily traffic per 1,000 contiguous PGIS through a combination of new and/or replaced impervious wetland,within one mile from the project site. sf building area). Facilities options include API or CP separator,linear sand filter,catch basin inserts. surface for redevelopment projects,or<1 acre of contiguous PGPS added and/or modified. These projects shall employ a wetpond sized such that the design water surface area Step 3—Determine if Infiltration for pollutant removal is practical(Infiltration is generally required if sites physical/soils criteria are met). Pretreatment 2. Cost Exemption for redevelopment projects having < $500,000 of total site shall be a minimum of one percent of the impervious surface area in the drainage with presettling basin or basic treatment BMP(from step 6)is required. If infiltration is not practical,proceed to Step 4. improvements,and<5,000 square feet of new PGIS will be added,and,<1 acre subbasin contributing to the facility. The design volume shall be a minimum of the Step 4—Determine if phosphorous control is required. This applies to projects within watersheds determined by local governments,Ecology,or US of contiguous PGPS will be added and/or modified. total volume of runoff from the developed conditions during a water quality design EPA to be sensitive to phosphorus and that are managed to control phosphorus inputs considering informational sources such as plans,water bodies 3. Forested Open Space Exemption for Rural Residential Projects that 65%of the storm event having a total precipitation that is equal to one-third of the 2-year,24-hour reported under section 305(b)and 319(a)of the Clean Water Act. Guidance for facility selection is provided and is very similar to the Enhanced unsubmerged portion of the natural discharge area is set aside as forested open total precipitation. A wetvault or water quality swale may be used when a wetpond is Treatment Requirements. space, and runoff from roads,driveways, and lawns is dispersed meeting certain not feasible. Step 5—Determine if Enhance Treatment required(required for industrial,commercial,multi-family,and arterials discharging to fish bearing tributaries, criteria. accept for those areas providing basic treatment,i.e.,that can utilize infiltration). Enhance Treatment options include infiltration with appropriate 4. Standard Infiltration Exemption if runoff from PGIS and PGPS surfaces is SR#6,Coalescing Plate Oil/Water Separators: This requirement applies to proposed pretreatment,large sand filter,amended sand filter,treatment wetland,and two facility treatment trains. infiltrated in soils meeting certain infiltration rate criteria projects constructing more than 5 acres of impervious surface subject to petroleum Step 6—Select a basic treatment facility(biofiltration swale,filter strip,basic wetpond,wetvault,etc.) 5. Soil Treatment Exemption if the runoff PGIS is infiltrated in soils that meet the storage or transfer,high vehicular use,or heavy equipment use,storage,or 'groundwater protection criteria." maintenance. Projects meeting this threshold are required to treat runoff with a Definitions: Design Standard: Water quality volume to be treated: When a design volume is coalescing plate,or equivalent oillwater separator. High vehicular use is defined as ■ Threshold Discharge Area-An onsite area draining to a single natural discharge location or multiple natural discharge locations that combine within used,it is intended that 95%of the annual average runoff volume be treated. The 2,500 trips per day. The design flow rates is the water quality design storm event one-quarter mile downstream(as determined by the shortest flowpath). peak design flows(below)will treat this volume. having a total precipitation that is equal to one-third of the 2-year,24-hour total ■ Pollution-generating impervious surfaces(PGIS-Those impervious surfaces considered to be a significant source of pollutants in stormwater runoff. ° precipitation.Runoff above this flow must bypass the separator. The separator must Such surfaces include those which are subject to:vehicular use;industrial activities;or storage of erodible or leachable materials,wastes,or Water quality design flow;If preceding detention,the design flow shall be 60/°of the chemicals,and which receive direct rainfall or the run-on or blow-in of rainfall. Examples include erodible soils that are stockpiled,uncovered developed 2-year peak. If downstream of detention facilities,the design flow shall be be installed upstream of other quality and quantity controls. process wastes,manure,fertilizers,oily substances,ashes,kiln dust,and garbage dumpster leakage.Metal roofs are also considered to be PGIS the 2-year peak. unless they are coated with an inert,non-leachable material(e.g.,baked-on enamel coating). A surface,whether paved or not,shall be considered Also,under Special Requirement#5 Oil Control,if a project develops a high use site subject to vehicular use if it is regularly used by motor vehicles.The following are not considered regularly-used surfaces:paved bicycle pathways or is a redevelopment project proposing$100,000 or more of improvements to a high separated from and not subject to drainage from roads for motor vehicles,fenced firelanes,and infrequently used maintenance access roads. use site,then the project must treat runoff using an oil control treatment option from ■ Pollution-generating pervious surfaces(PGPS)-Any nonimpervious surface subject to use of pesticides and fertilizers or loss of soil.Typical PGPS the High Use menu. The oil control options in the High Use menu include catch basin include lawns,landscaped areas,golf courses,parks,cemeteries,and sports fields. inserts,coalescing plate or API oil water separators. rX001159_3335 7 Table 3-1 (continued) City of Renton — Stormwater Manual Comparison Stormwater Management Manual for Western Washington(August 2001) 1998 King County Surface Water Design Manual 1990 King County Surface Water Design Manual 2.5.7 MR#7: Flow Control Applicability and Threshold. Flow control facilities can be exempt for discharges to major water bodies The comparable requirement in the manual is Core Requirement#3 Runoff Control. The comparable requirement in the manual is Core Requirement No.3 Runoff Control. (Lake Washington applicable to Renton)that meet the following;is drained by a constructed conveyance Applicability and Threshold: Applies to projects adding>5,000 sf of impervious surface,or 2,000 sf if within an Threshold: Peak rate runoff control is required for projects that add more than 5,000 sf of new system(e.g.,pipes,ditches,etc.)and extends to the ordinary high water line of the receiving water,and is identified Landslide Hazard Area. For single-family residences,a Small Site Drainage Review is Required. impervious area,unless an exemption applies. Peak rate runoff control is not required for the stabilized to prevent erosion;and does not divert from or increased flow to an existing wetland,stream,or Quantity control is not required for the following Exemptions: following exemptions: . near-shore habitat sufficient to cause a significant adverse impact. Local governments may petition Ecology to exempt projects in additional areas. Flow control facilities are required for projects in which the Impervious Surface Exemption if<10,000 sf of new impervious surface added,and certain criteria are met(i.e., 1. If the post-developed peak runoff rate for the 100-year,24-hour design storm is less than 0.5 cfs total of effective impervious surfaces(see definition below)is 10,000 sf or more in a threshold discharge area cleared is<35%or less and Small Site Drainage flow control BMPs are applied,etc.) more than the predeveloped peak runoff rate,or area,converts 3/4 acres or more of native vegetation to lawn or landscape,or convert 2.5 acres or more of Peak Flow Exemption if the project improvements generate<0.1 cfs increase for the 100-year peak flow rate,and 2. The project will discharge directly to a regional facility,a receiving water(including lake native vegetation to pasture in a threshold discharge area,or projects that cause a 0.1 cfs increase in the the certain criteria are met. Washington,Cedar River,and.the Green River(below river mile 6)) 100-year flow frequency from a threshold discharge area. That portion of any development project in which Peak rate runoff control can be achieved through detention or retentionfinfiltration facilities. For the above thresholds are not exceeded shall apply Onsite Stormwater Management BMPs(MR#5). Forested Open Space Exemption for Rural Residential Projects if at least 65%of the unsubmerged portion of the detention facilities,the design standard for runoff control is to detain post-developed peak flow rates Application of Onsite BMPs can also be used as a credit to reduce the size of flow control facilities. It is natural discharge area is set aside as forested open space for a proposed rural residential project and runoff from for the 2-year and 10-year events to the pre-developed conditions,plus a 30%safety factor. also noted that the flow control requirements for projects draining to wetlands shall meet MR#8. new impervious surfaces will be dispersed over native vegetation using the small site drainage flow control BMPs. Additional detention,up to the 100-year event can be required if their downstream impacts are Direct Discharge Exemption if a project drains to one of the'major receiving waters'listed(Cedar River and Green anticipated from the project. Stormwater discharges shall match developed discharge durations to to the full 50- durations for the range River above RM 6 S.BoeingAccess Road in Renton provided certain criteria are met. of predeveloped discharge rates from 50%of the 2-year peak flow up to the full 50-year peak flow. The ( ) )p Retention/infiltration facilities. The manual does not specify that infiltration facilities are encouraged pre-developed condition to be matched shall be a forested condition land cover,regardless of the sites Peak Flow Exemption for Urban Residential Infill Projects for family residential project located within an Urban over detention ponds. The manual does specify certain requirement necessary for infiltration to be current land cover condition,unless reasonable,historic information is provided that indicates the site was Growth Area if the project will generate less than a 0.4 cfs increase the 100-year peak flow,and certain criteria are used. If the site is in a closed depression or if there is no runoff from the site for the pre-developed 2- prairie prior to settlement(modeled as"pasture"in the Western Washington Hydrological Model). The met. and 10-year events,the project must provide storage for the 100-year 24-hour event as well as the standard intends to maintain the total amount of time that a receiving stream exceeds an erosion-causing 100-year 7-day event. Discretionary Exemption for Infill Projects whereby DDES may grant an exemption from the flow control threshold based upon historic rainfall and natural land cover conditions. requirements provided certain criteria are met. Pre-developed Condition. Pre-developed site condition is considered to be the current developed The new standard will increase the required size of flow control facilities compared to the 1992 Manual. Note that Ecology has stated that the County's Exemptions are not technically equivalent to the Technical Manual. condition of the site(if it was developed after 1979 according to approved drainage plan-this applies Facilities would be approximately 2.3 times larger for the conversion of pastureland to impervious surfaces to most development)or the site condition as it existed in 1979. and 1.4 times larger for the conversion of forest land to impervious surfaces. The significant increase in Methodology: The use of KCRTS model is required and area-specific flow control standards are established and the size of the flow control facilities is due to the assumed pre-developed,forested land cover condition, identified by a map within the manual. The standards include; use of the flow control duration standard and the use of continuous simulation hydrologic model. The 1992 Level 1: Match 2-and 10-year predeveloped peak flows—this is applied in areas where maintaining peak flows is Ecology Manual allowed the flow control facility sizing to be based upon the existing condition land cover sufficient to protect conveyance systems for the site. Level 2: Meet Level 1 plus match durations for predeveloped peak flows ranging from half the 2-year up to the full Definitions: 50-year flow—this is applied in areas sensitive to erosion and increased durations • Effective Impervious Surface-_impervious surfaces that are connected via sheet flow or discrete Level 3: Meet level 2 plus match 100 year peak predeveloped peak flow—this is applied to areas draining to conveyance to a drainage system.Impervious surfaces on residential development sites are not considered effective if the runoff is dispersed through at least one hundred feet of native vegetation. severe flooding problems. Ponds may need to be sized larger if downstream problem is identified. Retention/Infiltration System Sizing Requirements. The manual does not specify that infiltration facilities are encouraged over detention ponds. For infiltration ponds,a presettling pond is required. Presettling ponds can be a water quality facility from the Basic Water Quality menu or a pond with a volume equal to 0.75 times the runoff from the mean annual storm. Infiltration ponds shall be sized for the 100-year event using KCRTS. Pre-developed Condition. Pre-developed site condition is considered to be the current developed condition of the site(if it was developed after 1979 according to approved drainage plan-this applies to most development)or the site condition as it existed in 1979. i 1 X001159 3335 8 ' Table 3-1 (continued) City of Renton —Stormwater Manual Comparison 1 ' Stormwater Management Manual for Western Washington(August 2001) 1998 King County Surface Water Design Manual 1990 King County Surface Water Design Manual MR#8: Wetlands Protection Applicability and Threshold: Required for projects whose stormwater discharges into a wetland,either There is no separate core or special requirement associated with projects draining to wetlands. Altematively,the There is no special or core requirement that includes the same protects discharges to wetlands in the ' directly or indirectly through a conveyance system. The thresholds identified in MR#6—Runoff manual provides.additional protection for wetlands through other minimum requirements and the County's same way. However Special Requirement No.8—Use of Lakes,Wetlands,or Closed Depressions Treatment,MR#7—Flow Control are applied to discharges to wetlands. Environmentally Sensitive Ordinance. Through the off-site analysis requirement,downstream wetlands can be for Peak Rate Runoff Control,does have some requirements affecting wetlands. The requirements Requirements: Discharges to wetlands shall maintain the hydrologic conditions,hydrophytic vegetation, identified. In some cases,Level 3 flow control(duration-matching and peak-matching performance standard)can also include limits on the increase in flood levels for the wetland. This SR also contains similar and substrate characteristics necessary to support existing and designated uses unless an assessment is be required,which is effective in preventing significant increases in water surface levels of lakes,wetlands,and requirements for lakes and closed depressions. completed consistent with specific criteria referenced in the manual. Stormwater treatment and flow closed depressions. The standard is primarily applied in areas that drain to certain lakes,wetlands,or closed control facilities shall not be built within a natural vegetated buffer,except for necessary conveyance depressions where the County has determined that a higher average level of flow control is needed to prevent ' systems;or as allowed in wetlands approved for hydrologic modification and/or treatment in accordance aggravation of existing documented flooding problems. with specific criteria contained in the manual. The objective of this MR is to ensure that wetlands receive the same level of protection as any other The manual also has specific requirements for protection of sphagnum bog wetlands. These wetlands support waters of the state. Changes in water levels and the frequency and duration of inundations are of unique vegetation communities,and they tend to develop in areas where water movement is minimized. ' particular concern. Sphagnum bog wetlands are generally uncommon in the Puget Sound area. A Special water quality treatment Supplemental guidelines are provided in the manual for discharges to natural wetlands and wetlands menu is applied for Sphagnum Bog Protection. The treatment goals for protection of sphagnum bog wetlands constructed as mitigation. While it is always necessary to pre-treat stormwater prior to discharge to a include the control of nutrients,alkalinity,and pH. ' wetland,there are limited circumstances where wetlands may be used for additional treatment and detention of stormwater. These situations are considered in the supplemental guidelines. 1 1 1 1 1 1 X001159 3335 9 Table 3-1 (continued) ' City of Renton — Stormwater.Manual Comparison 1 Stormwater Management Manual for Western Washington(August 2001) 1998 King County Surface Water Design Manual 1990 King County Surface Water Design Manual MR#9: Basin/Watershed Planning Projects may be subject to equivalent or more stringent MRs for erosion control,source control,treatment,and The comparable requirement in the manual is Special Requirement#1 Other Adopted Area-Specific Several special requirements in the manual include requirements that are similar to that of Ecology's operation and maintenance,and alternative requirements for flow control and wetlands hydrologic control as Special Requirements. MR#9. These special requirements essentially serve the same function as the 1998 KCSWDM SR ' identified in Basin/Watershed Plans. BasinlWatershed plans shall evaluate and include,as necessary, #1. These are described as follows: retrofitting urban stormwater BMPs into existing development and/or redevelopment in order to achieve Under this SR projects maybe subject to other area-specific drainage requirements. These can include watershed wide pollutant reduction and flow control goals that are consistent with requirements the federal Special District requirements,zoning and land use restrictions,and other adopted area-specific regulations SR#1,-Critical Drainage Areas,states that for any proposed project area that lies within a designated Clean Water Act. that include requirements that have a more direct bearing on the drainage design of a proposed project. critical drainage area,the drainage review and engineering plans shall be prepared in accordance with , These regulations include the following: the special critical drainage area requirements that were formally adopted by public rule. Standards developed from basin plans shall not modify any of the above MRs until the basin plan is formally ■ Critical Drainage Areas CDAs: The Countyestablishes CDAs in areas where floodingand/or erosion adopted and implemented by the local governments within the basin,and approved or concurred with by g ( ) SR#2,Compliance with an Existing Master Drainage Plan,states that if a project lies within an n area conditions present an imminent likelihood of harm to the welfare and safety of the surrounding covered by an approved Master Drainage Plan,then the projects drainage review and engineering Ecology. community. The special requirements in CDAs typically include more restrictive flow control and plans shall be prepared in accordance with an special requirements of the Master Drainage Plan. ' �Y• P q ty Y P P P Y P � 9 Obfective. To promote watershed-based planning as a means to develop and implement comprehensive,water clearing standards. Maps showing CDA boundaries are available from DNR or DDES. Master Drainage Plans are comprehensive drainage system plans that are prepared for Master quality protection measures. Primary objectives of basin planning are to reduce pollutant loads and hydrologic ■ Master Drainage Plans(MDPs): MDPs are comprehensive drainage plans prepared for urban planned Planned Developments or other large proposed projects. impacts to surface and ground waters in order to protect beneficial uses. developments or other large, complex projects. Projects covered by a MDP must meet any adopted SR#4,Adopted Basin or community Plans,states that for any proposed project area that lies within requirements specific to that plan. an adopted Basin or Community Plan area,the drainage review and engineering plans shall be ' Supplemental Guidelines. Though MRs#1 through#8 establish general standards for individual sites,they do ■ Basin Plans (BPs): The King County Council adopts basin plans to provide for the comprehensive not evaluate the overall pollution impacts and protection opportunities that could exist at the watershed level. In assessment of resources and to accommodate growth while controlling adverse impacts to the Prepared in accordance with the special critical drainage area requirements of the adopted Basin or order for a basin plan to serve as a means of modifying the MRs the following conditions must be met: environment. A basin plan may recommend specific land uses, regional capital projects, and special Community Plan. ■ The plan must be formally adopted by all jurisdictions with responsibilities under the plan,and all ordinances drainage requirements for future development within the basin area it covers. ' or regulations called for by the plan must be in effect. Lake Management Plans(LMPs): The King County Council adopts lake management plans to provide Basin planning provides a mechanism by which the MRs and implementing BMP's can be evaluated and for comprehensive assessment of resources and to accommodate growth while controlling adverse refined based on an analysis of an entire watershed. Basin plans are especially well suited to develop control impacts from nutrient loading to selected lakes. A lake management plan may recommend nutrient , strategies to address impacts from future development and to correct specific problems whose sources are control through special drainage and source control requirements for proposed projects within the area known or suspected. Basin plans can be effective at addressing both long-term cumulative impacts of pollutant it covers. loads and short-term acute impacts of pollutant concentrations,as well as hydrologic impacts to streams, Shared Facility Drainage Plans(SFDPs): SFDPs are approved by King County to allow two or more wetlands,and ground water resources. The manual mentions USGS developed software called"GenScn" projects to share drainage facilities required by the manual. (Generation and Analysis of Model Simulation Scenarios)that can facilitate basin planning. The program is a Windows based use of HSPF that predicts water quality and quantity changes for multiple scenarios of land use Examples of special drainage requirements include: more or less stringent flow control,more extensive and water management within a basin. Examples of how Basin Planning can alter the MRs of this manual are water quality controls,forest retention requirements,infiltration restrictions,groun dwater recharge given in Appendix I-A. provisions,and discharge to a constructed regional flow control or conveyance facility. ' 1 X001159_3335 10 ' 1 Table 3-1 (continued) City of Renton — Stormwater Manual Comparison ' Stormwater Management Manual for Western Washington(August 2001) 1998 King County Surface Water Design Manual 1990 King County Surface Water Design Manual MR#10: Operation and Maintenance An operation and maintenance manual that is consistent with the provisions in Volume V of the manual shall be The comparable requirement in the manual is Core Requirement No.6 Maintenance and Operations. The comparable requirement in the manual is Core Requirement No.6 Maintenance and provided for all proposed stormwater facilities and BMPs,and the party(or parties)responsible for maintenance Operations. Maintenance and operation of all drainage facilities is the responsibility of the applicant or property owner, and operation shall be identified. At private facilities,a copy of the manual shall be retained onsite or within except those facilities for which the County is granted an easement,tract,or right-of-way and officially This requirement is very similar to the one in the 1998 Manual. reasonable access to the site,and shall be transferred with the property to the new owner. For public facilities,a assumes maintenance and operation. The Manual also establishes maintenance standards. ' copy of the manual shall be retained in the appropriate department. A log of maintenance activity that indicates what actions were taken shall be kept and be available for inspection by the local government. Objective: To ensure that the maintenance responsibility for drainage facilities is clearly assigned and that Objective. To ensure that stormwater control facilities are adequately maintained and operated properly. these facilities will be properly maintained and operated in perpetuity. A section of the required Technical Information Report(TIR)(see MR#2)is to include an operation and ' Supplemental Guidelines. Inadequate maintenance is a common cause of failure for stormwater control facilities. maintenance manual. The manual is to contain a brief description of the facility,what it does,and how it The description of each BMP in Volumes 11,III,and V includes a section on maintenance. Chapter 4 of Volume V works. In addition,the manual is to include a copy of the Maintenance Requirements for Privately includes a schedule of maintenance standards for drainage facilities. Local governments should consider more Maintained Drainage Facilities(in Appendix A of the manual)and provide an outline of the maintenance detailed requirements for maintenance logs,such as a record of where wastes were disposed. tasks and the recommended maintenance frequency. The operation and maintenance manual is to be ' transferred to the new owner. A log of maintenance activity indicating when cleaning occurred and where waste was disposed of shall also be kept by the owner and be available for inspection by the County. The County may inspect all privately maintained drainage facilities for compliance with these requirements. If ' property owner(s)fail to maintain their facilities,the County may issue a written notice specifying the required actions. If these actions are not performed in a timely manner,the County may enter the property to perform the actions needed and bill the property owner(s)for the cost of the actions. If the proposed project is a commercial,industrial,or multifamily development or redevelopment,or a ' single-family residential building permit,a"Declaration of Covenant"must be recoMed to grant access by the County for inspection and to agree to the maintenance requirements. The manual also establishes the requirements for which the County will assume maintenance and operation for residential subdivisions(except where such facilities are approved by King County to be ' maintained by the homeowners association). ' X001159 3335 1 1 Table 3-1 (continued) ' City of Renton — Stormwater Manual Comparison Stormwater Management Manual for Western Washington(August 2001) 1998 King County Surface Water Design Manual 1990 King County Surface Water Design Manual Optional Guidance#1 -Financial Liability ' p _ Optional Guidance'#1—Financial Liability,relates to performance bonding or other appropriate financial The comparable requirement in the manual is Core Requirement No.7 Financial Guarantees and The comparable requirement in the manual is Core Requirement No.7 Bonds and Liabil'fty. guarantees,which is encouraged for all projects to ensure construction of drainage facilities in compliance with Liability. While the Ecology manual identifies this as an optional guidance,the County manual incorporates it ' these standards. In addition,it is recommended that project applicants post a two-year financial guarantee of the While the Ecology identifies this an optional guidance,the County manual incorporates it as a as a requirement.This requirement is very similar to the one in 1998 Manual. satisfactory performance and maintenance of any drainage facilities that are scheduled to be assumed by the local requirement. government for operation and maintenance. This requirement states that all drainage facilities constructed for projects(except downspout infiltration ' Obiective. To ensure that development projects have adequate financial resources to fully implement stormwater and dispersion systems)must comply with the financial guarantee requirements in King County management plan requirements and that liability is not unduly incurred by local governments. Ordinance 12020 and the liability requirements of King County Code 9.04.100. There are two types of Supplemental Guidelines. The type of financial instrument required is less important than ensuring that there are financial guarantees: the drainage facilities restoration and site stabilization guarantee,and the adequate funds available in the event that non-compliance occurs. drainage defect and maintenance guarantee. The two requirements are summarized below. ' Objective: To ensure financial guarantees are posted to sufficiently cover the cost of correcting,if necessary',incomplete or substandard drainage facility construction,and to warrant for two years the satisfactory performance and maintenance of those newly-constructed drainage facilities to be ' assumed by King County for maintenance and operation. It is also intended to ensure that a liability policy is provided which protects the proponent and the County from any damages relating to the construction or maintenance of required drainage facilities by private parties. Drainage Facilities Restoration and Site Stabilization Financial Guarantee: This guarantee must be ' posted prior to beginning construction and be an amount sufficient to cover the cost of corrective work on or off the site performed specifically for the given project. The County may waive the requirement of this guarantee on projects proposing only minor modifications or improvements to the drainage system ' (e.g.,catch basin inserts,spill control devices,pipe replacements,etc.). Before the County releases the guarantee,the applicant must;construct the drainage facilities,receive final construction approval from the County,and pay all required fees. Drainage Defect and Maintenance Financial Guarantee: For constructed drainage facilities to be ' maintained and operated by King County,the applicant must post a drainage defect and maintenance financial guarantee for a period of two years and maintain the drainage facilities during the two-year period. Before the County will release the guarantee and assume maintenance responsibility,the applicant must;provide the required plat or easement documentation including setting survey corners, ' receive a final inspection to ensure the drainage facilities have been properly maintained and are operating as designed;and correct any defects noted in the final inspection. King County generally assumes the maintenance and operation of all storm water facilities in Plats ' including the conveyance systems,water quality treatment facilities and flow control facilities. '"Optional Guidance"is considered guidance offered by Ecology as recommendations to local governments.Ecology considers their use to be in the best interest of the general public and the environment but will not make their implementation a requirement for manual equivalency. X001159_3335 12 ' Table 3-1 (continued) City of Renton — Stormwater Manual Comparison Stormwater Management Manual for Western Washington(August 2001) 1998 King County Surface Water Design Manual 1990 King County Surface Water Design Manual Optional Guidance#2: Off Site Analysis and Mitigation Optional Guidance #2—off-site analysis and mitigation is a recommendation that development projects The comparable requirement in the manual is Core Requirement No.2 Offsite Analysis. The comparable requirement in the manual is Core Requirement No.2 Offsite Analysis. ' discharging stormwater offsite should be required to submit an offsite analysis report. The report should While the Ecology identifies this an optional guidance,the County manual incorporates it as a requirement. While the Ecology identifies this as an optional guidance,the County manual incorporates it as a assess the potential off-site water quality,erosion,slope stability,and drainage impacts associated with the project and propose appropriate mitigation of those impacts. An initial qualitative analysis shall extend All proposed projects must submit an offsite analysis report that assesses potential offsite drainage impacts requirement. The Offsite Analysis is similar to the requirements in the 1998 Manual. Differences downstream for the entire flow path from the project site to the receiving water or up to one mile,whichever is associated with development of the project site and propose appropriate mitigation of those impacts. include; y P project P Y Y Obiective: To identify and evaluate offsite drainage problems that may be created or aggravated by the The project is required to identify the upstream tributary drainage area that drains onto the site,but less. The analysis must also extend upstream of the ro ect to a point where an backwater effects created b P 1 � ty P ry 9 the project cease. Upon review of the qualitative analysis,the local administrator may require that a project,and to determine appropriate measures for preventing aggravation of those problems. the requirement to perform an upstream analysis is not specified. proposed p Ip g gg p There is less definition or classification of the types of downstream problems (i.e., they are not quantitative analysis be performed. The rima component of the offsite analysis is the downstream analysis,which examines the drainage The existing or potential impacts to be evaluated and mitigated shall include: p pry p y Y 9 classified into conveyance system nuisance,sever erosion and severe flooding),rather the applicant system within one-quarter mile downstream of the project site or farther distances may be required under must describe the downstream problem and then for any problem of concern,the application needs ■ Conveyance system capacity problems; certain conditions. A secondarycomponent of the offsite analysis is an evaluation of the upstream ■ Localized flooding; p y P to demonstrate the project has been designed so that it neither aggravates the problem nor creates g drainage system to verify and document that impacts will not occur as a result of the proposed project. a new problem. ■ Upland erosion impacts,including landslide hazards; The evaluation must extend upstream to a point where any backwater effects created by the project cease. • Stream channel erosion at the ouffall location; ■ Violations of surface water quality standards as identified in a Basin Plan or a TMDL Exemptions are listed for projects where there is sufficient information to conclude that the project will not (Water Clean-up Plan);to violations of ground water standards in a wellhead protection area. have a significant adverse impact;(e.g.does not contain critical area,adds<5,000 sf of new impervious surface and does not construct a drainage pipe/ditch that is 12 inches or more in sizeldepth;or does not The objective of this guidance is to identify and evaluate offsite water quality,erosion,slope stability,and change the rate,volume,duration,or location of discharges to and from the project site). drainage impacts that may be caused or aggravated by a proposed project,and to determine measures for preventing impacts and for not aggravating existing impacts. Aggravated is defined meaning"increasing the The downstream analysis must consider the existing conveyance system(s)for a minimum flowpath frequency of occurrence and/or severity of a problem." distance for the further of(1)of one-quarter mile downstream,or(2)a point where the project site area constitutes less than 15%of the tributary area. This minimum distance may be increased if a problem is Projects should be required to initially submit,with the permit application,a qualitative analysis of each identified as part of the review of information(which must extend a mile downstream),or downstream downstream system leaving a site. The analysis should include four tasks: mitigation is proposed,or at County discretion. Task 1—Define and map the study area There are three levels of analysis. The Level 1 downstream analysis is a qualitative survey and is Task 2—Review all available information on the study area composed of the same four task listed under Ecology's guidance. Upon review of the Level 1 analysis,the Task 3—Field inspect the study area County may require a Level 2 or 3 downstream analysis. Levels 2 and 3 downstream analyze quantify Task 4—Describe the drainage system,and its existing and predicted problems(the descriptions should be downstream problems by providing information on the seventy and frequency of an existing problem or the used to determine whether adequate mitigation can be identified,or whether more detailed quantitative likelihood of creating a new problem. A Level 2 analysis is a rough quantitative analysis(non-survey field analysis is necessary). data,uniform flow analysis). Level 3 is a more precise analysis(survey field data,backwater analysis)of significant problems. If conditions warrant,additional,more detailed analysis may be required beyond Level 3. Downstream problems requiring special attention or mitigation are defined or classified into 3 types (conveyance system nuisance,severe erosion and severe flooding).A proposed project must not significantly aggravate existing downstream problems. The manual does not require development proposals to fix or otherwise reduce the seventy of existing downstream drainage problems,although doing so may be an acceptable mitigation. In addressing downstream problems,the easiest of the provisions to implement will often be that of additional onsite flow control. This involves designing the required onsite flow control facility to meet an additional set of performance criteria targeted to prevent significant aggravation of specific downstream problems. A set of predetermined flow control performance criteria corresponding to each of the three types of downstream problems is provided. 2"Optional Guidance"is considered guidance offered by Ecology as recommendations to local governments.Ecology considers their use to be ' in the best interest of the general public and the environment but will not make their implementation a requirement for manual equivalency. X001159 3335 13 Table 3-1 (continued) City of Renton — Stormwater Manual Comparison t Stormwater Management Manual for Western Washington(August 2001) 1998 King County Surface Water Design Manual 1990 King County Surface Water Design Manual Adjustments' Adjustments to the MRs may be granted prior to permit approval and construction. The local government The County manual includes an Adjustment Process that is comparable to Ecology's Adjustments and The County Manual includes a Variance Process that is comparable to Ecology's Adjustments and drainage manual administrator may grant an adjustment provided that a written finding of fact is prepared, ExceptionsNariances. ExceptionsNariances. The Variance Process in the 1990 manual is simplified from that of the 1998 that addresses the following: The adjustment process is used when a project proponent desires to vary from one of the core or special manual. Different types of"adjustments",as described in the 1998 manual,are not defined. ■ The adjustment provides substantially equivalent environmental protection. requirements,or other requirements/standards contained in the manual. There are several types of Variances can be obtained for both core and special requirements.In general,variances may be ■ The objectives of safety,function,environmental protection and facility maintenance,based upon adjustments as follows: granted based on the following criteria; sound engineering,are met. • The variance would produce a compensating or comparable result which is the public interest,and Standard Adjustments: These are adjustments of the standards and requirements contained in the following . The variance would meet the objectives of safety,function,appearance,e nvironmental protection Exceptions/Variances' chapters and sections of this manual: and maintainability,based on sound engineering judgment Exceptions to the MRs may be granted prior to permit approval and construction. The drainage manual 0 Chapter 2,Drainage Plan Submittal Chapter 4,Conveyance System Analysis and Design administrator of the local government may grant an exception following legal public notice of an application . Chapter 5,Flow Control Design for an exception,legal public notice of the administrator's decision on the application,and a written finding . Appendix C,Small Site Drainage Requirements of fact that documents the following: • Appendix D,Erosion and Sediment Control Standards ■ There are special physical circumstances or conditions affecting the property such that the strict Complex Adjustments: Complex adjustments typically require more in-depth review because they deal with application of these provisions would deprive the applicant of all reasonable use of the parcel of land in more complicated requirements or requirements that affect basic County policies or other agencies. These question,and every effort to find creative ways to meet the intent of the MRs has been made;and adjustments deviate from the requirements contained in the following chapters and sections of this manual: • That the granting of the exception will not be detrimental to the public health and welfare,nor injurious . Chapter 1,Drainage Review and Requirements to other properties in the vicinity and/or downstream,and to the quality of waters of the state;and ■ Chapter 3,Hydrologic Analysis and Design ■ The exception is the least possible exception that could be granted to comply with the intent of the ■ Chapter 6,Water Quality Design , MRs. ■ Appendix A,Maintenance Standards ■ Appendix B,Master Drainage Plan Preapplication Adjustments: This type of adjustment may be requested when the applicant needs an adjustment decision to determine if a project is feasible(viable)before funding a full application. The approval of preapplication adjustments is tied by condition to the project proposal presented at a preapplication meeting. Experimental Design Adjustments: This type of adjustment is used for proposing new designs or methods that are not covered in the manual,that are not uniquely site specific,and that do not have sufficient data to establish functional equivalence. Blanket Adjustments: This type of adjustment may be established by the County based on approval of any of the above-mentioned adjustments. Blanket adjustments are usually based on previously approved adjustments that can be applied routinely to other projects where appropriate. Blanket adjustments are also used to effect minor changes or corrections to manual design requirements or to add new designs and methodologies to the manual. Criteria ' Adjustments may be granted provided that granting the adjustment will achieve the following: 1. Produce a compensating or comparable result that is in the public interest,and 2. Meet the objectives of safety,function,appearance,environmental protection,and maintainability based on sound engineering judgment. Where meeting the criteria for producing a compensating or comparable result will deny reasonable use of a property,the applicant shall produce the best practicable alternative as determined by the County. Experimental design adjustments will be approved if the following criteria are met: ' 1. The new design is likely to meet the identified target pollutant removal goal or flow control performance based on limited data and theoretical considerations,AND 2. Construction of the facility can,in practice,be successfully carried out,AND 3. Maintenance considerations are included in the design,and costs are not excessive or are born and reliably performed by the applicant or property owner,AND 4. A share of the cost of monitoring to determine facility performance is contributed by the applicant or property owner. Conditions for approval may include a requirement for setting aside an extra area and posting a financial guarantee equivalent to the construction of a conventional facility should the experimental facility fail. Once satisfactory operation of the experimental facility is verified,the set aside area could be developed and the financial guarantee released. 3 Ecology's Adjustments and ExceptionsNariances are similar and are combined on this page. t X001159_3335 14 i ' Table 3-1 (continued) City of Renton — Stormwater Manual Comparison ' Stormwater Management Manual for Western Washington(August 2001) 1998 King County Surface Water Design Manual 1990 King County Surface Water Design Manual Floodplains/Flooding Delineation and Flood Protection Facilities ' There are no minimum requirements in the Ecology Manual comparable to these special requirements Special Requirement#2: Floodplain/Floodway Delineation Special Requirement No.9: Delineation of the 100 year Floodplain that are included in the KCSWDM. The County's manual includes floodplains and floodways regulations,in order to minimize flooding impacts to This requirement is similar to the SR#2 in the 1998 County manual. new development and to prevent aggravation of existing flooding problems by new development. Most of the t County's regulations and restrictions concerning development within the floodplain are found in its Sensitive Special Requirement No.10: Flood Protection Facilities for Type 1 and 2 Streams Areas Ordinance. This requirement is similar to the SR#3 in the 1998 County manual. Threshold: Projects containing or adjacent to a stream,lake,wetland,or closed depression. The 100-year floodplain boundaries(and floodway,if available or if improvements are proposed within the 100- ' year floodplain)on the site improvement plans and profiles,and on any final subdivision maps prepared for the proposed project,based on an approved flood hazard study. If an approved flood hazard study exists,it may be used as the basis for delineating the floodplain and floodway ' boundaries. If an approved flood hazard study does not exist,then one shall be prepared based on the requirements contained in the manual. Special Requirement#3: Flood Protection Facilities ' The purpose of this requirement is to implement a higher level of scrutiny on developing sites protected by levees,revetments,or berms,the flood protection facilities require a high level of confidence in their structural integrity and performance. Proper analysis,design,and construction are necessary to protect against the potentially catastrophic consequences if such facilities should fail. ' Threshold. Projects containing or adjacent to a Class 1 or 2 stream that have an existing flood protection facility or propose to construct a new or to modify an existing flood protection facility shall analyze and/or design the flood protection facilities to conform with the-Federal Emergency Management Administration(FEMA) ' regulations(44 CFR). The applicant is required to demonstrate conformance with FEMA regulations using the methods specified in the manual(Section 4.4.2). In addition,certain easement requirements must be met in order to allow County access for maintenance of the facility 1 1 1 1 1 1 X001159 3335 15 Section 4 CONSIDERATION FOR ' SELECTING A NEW DESIGN MANUAL As previously noted, the City is currently required by the Puget Sound Water Quality Management Plan, and will also likely be required by the pending NPDES Phase II ' Storm Water Permit, to adopt either the Ecology 2001 manual or equivalent standards. Future updates to these standards would have to occur when Ecology updated their 2001 manual or when the NPDES permit is re-issued once every 5 years. . The following paragraphs provide some discussion of different considerations that should be considered when the City moves through this process. Option of Creating New City of Renton Manual with Equivalent Standards ' Jurisdictions that choose to develop an alternative technical manual are directed to submit their manual to Ecology and demonstrate how the alternative manual is substantively equivalent to Ecology's. Ecology would then work with the jurisdiction to ensure that the alternative manual meets or exceeds the standards. Jurisdictions choosing to develop an alternative manual are directed to use Ecology's technical manual in the interim. Guidance criteria for equivalency reviews, excerpted from the 2001 Manual include: 1. The Minimum Requirements (Chapter 2) for new development and redevelopment, or their equivalents must be included in ordinance or enforceable rules adopted by the local government. More stringent requirements may be used, and/or the Minimum Requirements may be tailored to local circumstances through the use of basin plans or other similar water quality and quantity planning efforts. ' 2- The thresholds for and definitions of new development, redevelopment, land disturbing activities, impervious surfaces, maintenance, and pollution-generating ' surfaces should provide equivalent protection of receiving waters or equivalent levels of pollution treatment as those provided by Ecology's criteria. 3. An equivalent manual must include BMP selection and site planning processes ' that have outcomes that provide equivalent or greater protection to those in Ecology's manual. 4. The types of BMPs and design criteria for those BMPs specified by local governments must provide equivalent or greater protection than those contained in Volumes II through V of Ecology's manual. 5. Adjustment and Variance criteria similar to those in Volume 1 must be included. X001159_3335 12/27/02 Section 4 ' The resources likely required to develop an equivalent standard manual would be extensive. King County has spent considerable resources and has not yet obtained equivalency. Another disadvantage of this approach is that as there would be a level ' of uncertainty as to whether and when the City and Ecology could reach agreement for negotiating equivalency. Since the pending NPDES Phase II Permit will likely require the City to use the 2001 Ecology Manual in the interim until an equivalent manual is ' approved, there is no incentive for Ecology to ever approve an equivalent manual. Given Ecology's budget and staff resource limitations they would not be capable of reviewing very many equivalent manuals at one time. Option of Adopting 1998 King County Surface Water Design Manual An option many jurisdictions have taken is to adopt the 1998 KCSWDM. Since the current version is now being updated, the City would have to do another update when the County updates that manual to be equivalent to Ecology's. The 1998 KCSWDM is a significant improvement over the 1990 KCSWDM. However, the KCSWDM ' applies its treatment and flow control requirements based on geographic area. Since the County has not mapped recommended treatment and flow control for incorporated areas, the City would need to do this. As previously noted, Appendix B contains a , summary of the proposed changes to the manual to make it equivalent to the 2001 Ecology Manual. Some of the key differences where Ecology has indicated that the County manual is not equivalent include: ' ■ Certain exemptions ■ Limiting water quality treatment to the "Basic" (80% TSS removal) level for all redevelopment ■ Limited application of the Resource Protection Standard (Basic plus 50% zinc removal) for water quality treatment ■ Level 1 flow control does not meet Ecology's minimum standards and would need to be changed to Level 2 flow control (peak rate and duration control) ' ■ Flow control should be based on a predeveloped condition of "historic" forest/prairie rather than existing site conditions ' One option for consideration if the City wanted to adopt the 1998 KCSWDM now,and minimize the changes necessary when the County updated the manual would be to supplement this manual with the following: , ■ -Set the default flow control standard at King Co.'s Level II and assume the natural land cover condition , ■ Require use of King Co.'s "Resource Stream Protection Menu" for the same instances that Ecology applies its "Enhanced Treatment Menu;" Adopt the 2,000/7,000 sq. ft. thresholds for the application of what King Co. has/will have that are equivalent to Ecology's Minimum Requirements 1 - 5 ■ Adopt a redevelopment requirement similar to Ecology's 4-2 R. W. Beck X001159_3335 12/27/02 ' CONSIDERATIONS FOR SELECTING A NEW DESIGN MANUAL ' An advantage of adopting the KCSWDM is there would be less confusion with engineers, builders, and developers. They would become accustomed to using one set ' of standards in both unincorporated areas and incorporated areas (if other cities also use the updated KCSWDM). Another advantage is that it tends to be more "cookbook" and includes a better description of submittal and technical requirements. The submittal information and requirements for small projects (between 2,000 and 10,000 sf) are simplified and easier to apply. The manual also contains more specific requirements and thresholds that address development in landslide hazard areas. A ' disadvantage of adopting the KCSWDM is the County's timing in publishing an equivalent manual. If Ecology and King County have a disagreement over negotiating an equivalency decision, the City of Renton could like-wise be out of ' compliance. Another disadvantage to adopting another agencies manual is that when the other, agency makes changes to their manual, the City would have to either adopt those changes also or be forced to follow a manual that is no longer in publication as Renton is currently doing in using the 1990 KCSWDM. ' Aquifer Protection Ordinance With selecting either Ecology's or King County's manual, the City will need to implement the manual with additional requirements to make sure drainage standards ' are consistent with the City's Aquifer Protection Ordinance. For example, the ordinance limits the use of infiltration and open detention or water quality facilities in certain areas in the City. Obtaining Project Permits A potential issue with adopting King County's manual is that permitting agencies may, require new development projects to comply with the 2001 Ecology Manual. Both ' Ecology and King County were asked about this issue. Ecology indicated that they cannot guarantee what other agencies with a permit jurisdiction will do. However, Ecology will make it.clear that if it makes a determination that a local government ' stormwater management manual is equivalent to Ecology's manual, then it will recommend that the local manual be accepted by other state and Federal agencies. ' Another potential issue associated with the revised NPDES construction permit. With the threshold being reduced from 5 acres to 1 acre, there will be significantly more projects required to obtain an NPDES construction permit from Ecology. The NPDES ' construction pennit will require the project owner to prepare a Storm Water Pollution Prevention Plan (SWPPP) that complies with Ecology's Manual standards. A project owner would then have to consider multiple standards (Ecology's and Renton's) in preparation of this plan. Although the standards are similar, particularly with erosion control BMPs, there are differences such as a certified professional in erosion control is required to be involved on every project. ' X001159_3335 12/27/02 R. W. Beck 4-3 Section 4 ' Summary of Advantageous and Disadvantageous for Manual Alternatives , There are several options for deciding how to proceed with updating the City's storm water design standards for new construction to comply with the pending NPDES Phase 2 storm water permit requirements and to better facilitate the review and approval of projects in the City. Table 4-1 provides some considerations as well as advantageous and disadvantageous for these options. , Table 4-1 City of Renton , Stormwater Manuals and Advantageous and Disadvantageous RENTON STORM WATER DESIGN MANUAL OPTIONS MATRIX 'OPTIONS ADVANTAGES DISADVANTAGES 1. Do Nothing— None Violates Clean Water Act, ' Continue to use the Puget Sound Water Quality 1990 KCSWD Manual Management Plan requirements, and future , NPDES Phase II permit requirements. Potential liability to the City ' for non-compliance with the Clean Water Act and possibly the Endangered ' Species Act. • Water quality, habitat and other beneficial uses ' decreased for water bodies in Renton. • Permitting of new ' development projects and City projects become more problematic. , • Creates conflicts between other agency permit requirements and City , Stormwater requirements. • Standards out of date. • Manual is no longer in ' publication. 2. Adopt Ecology's Complies with Clean Water Act . One size fits all standards , 2001 Storm Water NPDES Phase II permit that may be difficult or not Manual requirements. make sense to apply Citywide. ' 4-4 R. W. Beck X001159_3335 12/27/02 , CONSIDERATIONS FOR SELECTING A NEW DESIGN MANUAL ' RENTON STORM WATER DESIGN MANUAL OPTIONS MATRIX ' OPTIONS ADVANTAGES DISADVANTAGES . Water quality, habitat and beneficial . Stormwater facility size and uses of water bodies in Renton are cost will increase. protected(Best Available Science). ■ Developers, planners, . Complies with the Puget Sound designers and reviewers ' Water Quality Management Plan (City staff)are not as familiar and GMA requirements. with Ecology's Manual as . Adoption could be done most quickly they are with King County's ' and with the least amount of work. manual format. . Eliminates conflicts between other Would have to adopt agency permit requirements and changes when Ecology City Stormwater requirements. makes changes to keep current with publication. 3. Adopt King County's . Same Advantages as Option 2,but Some County standards are 1998 Surface Water slightly more work would have to be not consistent with City Design Manual with done to making changes before it standards and would not be Revisions to be could be adopted. applicable or allowed. ' Equivalent to Ecology's ■ Manual is organized better for users Same cost and facility sizing Manual (developers,planners, designers requirements as Option 2, and reviewers) since it would have to be . Professional community and equivalent to Ecology's development community is familiar Manual. with manual,since it is widely used Would have to adopt throughout King County by Cities changes when King County and the County. makes changes to the . City is currently using the 1990 and Manual. ' the 1998 KCSWDM's is similarly Ecology will require, at a organized,so City staff would be minimum,the Manual to be more familiar with King County s updated when the NPDES Manual format than the Ecology Phase II permit is re-issued Manual every 5 years. Any update would have to be equivalent to Ecology's minimum standards exist in their Manual at that time of the update. 4. Develop and Adopt a . City would control any changes to Would require a significant Renton Storm Water the Manual. financial and staff resource Design Manual that is ■ The Manual could be better effort to develop manual. approved by Ecology as customized to reflect Renton's NPDES compliance would Equivalent design standards,development require Ecology's review and ' regulations and permit review approval as equivalent with processes. no guarantee that it would be approved. ' X001159_3335 12/27/02 R. W. Beck 4-5 Section 4 RENTON STORM WATER DESIGN MANUAL OPTIONS MATRIX ' OPTIONS ADVANTAGES DISADVANTAGES , Some of the same advantages as . Would be required to follow Alternative 2,including,complies Ecology's standards until the with Clean Water Act NPDES Phase manual is approved as II permit requirements, protecting equivalent. Water quality,habitat and beneficial ■ No incentives for Ecology to ' uses of water bodies in Renton are approve nor does Ecology protected, and would complies with have the staff resources. the Puget Sound Water Quality Management Plan and GMA Modification of minimum requirements. standards for specific areas in the City would require complicated hydrologic, hydraulic and water quality technical analysis to demonstrate equivalency, which would take time and significant resources. Ecology will require, at a minimum,the Manual to be ' updated when the NPDES Phase II permit is re-issued every 5 years. Any update would have to be equivalent to Ecology's minimum standards exist in their Manual at that time of the update. City would be responsible for ' updating the Manual in the future to reflect new City standards or other City changes,to incorporate and allow new technology and new science. ' t 4-6 R. W. Beck X001159_3335 12/27/02 ' Appendix A POWERPOINT PRESENTATIONS X001159_3335 12i27102 - Proposed Phase /I Rule What Does It Mean For the City of Renton ? } Federal Storm Water _ Mana ement Polic a► hr :: :u R. ♦ Clean Water Act of 1972 established NPDES ♦ 1987 amendments to , f;. 1 . the Clean Water Act required EPA to �r develop phased —� approach to regulating storm water under �"�` r NPDES ` ' 1 t Storm Water Management: Going Throu h the Phases ' ♦ Phase I: — Issued November 1990 4 — Addressed storm water discharges from medium and large municipal separate storm sewer systems ' (MS4s) — Addressed storm water discharges from industrial activities, including discharges from construction activities disturbing five acres or more Y y N Phase I Coverage-Snohomish,King,Pierce,Clark counties cities of and Seattle and Tacoma 1 2 ' 1 Storm Water Management: Going Through the Phases (continued) ♦ Phase IL 1 - R �� — Final rule signed December 1999 — Addresses storm water discharges from activities exempted under Phase I: • Construction activities disturbing between one and five acres • Light industrial activities not exposed to storm water • "Donut holes"--small MS4s located in a larger community regulated under Phase I(e.g.,a small municipality in a larger county) 1 — Addresses storm water discharges from: • Small MS4s in urbanized areas(pop.< 100,000) • Construction activities that disturb an acre or more 0, NPDES Phase 11 Schedule 1 - ♦ December, 1999: Published 12/99 — Requires Washington State Department of Ecology (Ecology) to issue a Permit by 12/02 — Requires coverage under permit by 03/03 A. ♦ Ecology expressing difficulty in meeting deadline 1 1 ' 3 t Key Differences Between Phase / and Phase11 v ♦ Phase II encourages General Permits ' i Application requirements streamlined } ♦ NPDES permitting authorities establish ' monitoring requirements ♦ Municipalities develop BMPs to address ;z minimum control measures �4 .r . Ecology's Role in lm 1 mentina Phase Il ♦ Ecology has NPDES permitting authoritYin Washington State ♦ Ecology responsible for developing permit ` requirements based on the Federal Rule f., ~P 1 4 , _£ Phase 11 Federal Rule Requirements Reduce discharge of pollutants from a regulated system to the f� maximum extent practicable � S � # Who is Covered by Phase Il? Automatically included: • Small MS4s located in urbanized areas (Renton is listed fu as an urbanized area in the federal rule) `- _ • Construction sites disturbing 1-5 acres 3 ♦ Sources regulated under existing NPDES program but exempted by ISTEA (industrial activities at facilities operated by municipalities with populations of less than 100,000 (such as non-point runoff from wastewater sewage treatment plants, vehicle maintenance area, and solid waste handling facilities) 5 ! Phase 11 Exemptions ♦ Tribally-owned systems that serve less than r " 1,000 people ♦ Any other system waived by NPDES permitting authority ♦ Industrial and other sources that provide "no 'k exposure" certification i ! Specify BMPs for 6 y Minimum Control M asures t. Public education and outreach on storm water -. impacts = ' 3 2. Public involvement/participation 3. Illicit discharge detection and elimination a. Construction site storm water runoff control ICY !s. Post-construction storm water management in new development and redevelopment 6. Pollution prevention/good housekeeping for municipal operations 6 For each of the minimum measures the MS4 must: ♦ Identify BMPs for each minimum measure ♦ Describe measurable goals for each BMP EPA has issued guidance on measurable goals .z� ♦ Describe the timing and frequency of actions . r �.� ♦ Identify specific entity responsible for implementation of the BMP Measurable Goals ♦. Not defined in the regulations ♦ A way by which implementation of the BMPs can be assessed. ♦ Measurable goals need to either serve as BMP design Y° objectives or goals that quantify the progress of implementation of the actions or performance of the permitee's BMPs. ♦ Does not necessarily measure whether a BMP is effective in achieving a specific amount of pollutant reduction. 7 :5 Minimum Control Measure #1: Public Education and Outreach MUST: ' Distribute educational materials to the community, or d ry� Conduct equivalent outreach activities about the impacts of storm water discharges on water bodies and the steps that the public can take to reduce pollutants in storm water runoff Minimum Control Measure #1: ' y Public Education and Outreach 4U £: EPA RECOMMENDED: ' May use materials provided by others Inform public on how to get involved in storm water program activities i Tailor program to target specific groups of entities, € particularly those likely to have significant storm water impacts Address the viewpoints and concerns of minority and disadvantaged communities 8 Minimum Control Measure #2: Public Involvement/Participation {y_ MUST: 9 Comply with State, Tribal and local public notice requirements EPA RECOMMENDED: Provide opportunities for public to participate (e.g., local stormwater management panel, volunteer monitoring) ' Minimum Control Measure #3: Illicit Discharge Detection and � * Elimination MUST: 1s, Develop a storm system map of all outfalls and the names of all receiving waters Prohibit non-storm water discharges, through an ordinance or other means, and implement appropriate enforcement procedures - ''•� Implement a plan to detect and address non-storm water discharges ' Inform public of hazards associated with illegal discharges and improper disposal of waste ' 9 `. Minimum Control Measure #3: Illicit Discharge Detection and Elimination ' EPA RECOMMENDED:, r A plan with procedures for: Locating priority problem areas Tracing the source of an illicit discharge Removing the source - Program evaluation &assessment Promotion of public reporting of discharges Distribution of outreach materials Storm drain stenciling , Minimum Control Measure #4: Construction Site Storm Water V� Runoff Control MUST: Develop a program to reduce pollutants from construction activities that disturb > 1 acre ' Use an ordinance, or other regulatory means, with penalties, that requires appropnate erosion and sediment controls and requirements to control construction site runoff Have procedures for: - site plan review site inspection & enforcement - public input 10 Minimum Control Measure #4: Construction Site Storm Water Runoff Control EPA RECOMMENDED: Procedures for site plan review should include review of individual pre-construction site plans Procedures for site inspections and enforcement could include steps to identify priority sites based on the nature of + the site, topography, soil characteristics, and receiving water quality. Provide appropriate educational and training measures for construction site operators 1 Minimum Control Measure #5: Post-construction Storm Water Manage ment in New a Development and Redevelopment MUST: ' Develop a program, using an ordinance or other A regulatory means, to address runoff from new development and redevelopment projects that disturb > 1 acre Implement strategies with a combination of structural and/or non-structural BMPs Ensure adequate long-term operation & maintenance (O&M) of BMPs (inspections) 11 S Minimum Control Measure #5: Post-construction Storm Water Management in New Development and Redevelopment , EPA RECOMMENDED: , t p s The BMPs chosen should: be appropriate for the local community minimize water quality impacts attempt to maintain pre-development runoff conditions Participate in watershed planning efforts Assess existing ordinances,policies, and programs that address storm water runoff quality Provide opportunities for public participation ' Minimum Control Measure #6: ' Pollution Prevention/Good Housekeeping y for Municipal Operations ii7�k� .cs a- '1 sr L " MUST Develop an 0&M program to prevent or reduce Y pollutant runoff from operations ' Include employee training to prevent and reduce ..3 storm water pollution from activities such as the maintenance of park and open space, buildings, t and storm water systems. 12 ' Minimum Control Measure #6: Pollution Prevention/Good Housekeeping for ' Municipal 0 erations 3 EPA RECOMMENDED: 3 , Maintenance activities and schedules, and long-term ' inspection procedures Controls on the discharge of pollutants from streets, salt/sand storage areas, waste transfer stations, etc. ' Procedures for disposing of waste from the MS4 Ensure new flood management projects assess impacts on water quality xE� City of Renton — Who is Affected PBPW 1 R a Utility Systems- Surface Water(primary) �g1 m Utility Systems—Water,Wastewater, Solid Waste, Maintenance Services,Development Services, Transportation System(Roads and Airport) Community Service Department (Parks,Facilities & r s Recreation) City Council—Utilities Committee Finance—Utility Billing Fire Department 13 Additional Elements f Ph II �� �' • Required to develop implementation schedule of A � activities or frequency of activities r � • Required to identify entity responsible for implementation µ ~ • You may work with another entity (e.g., county) to ' implement minimum control measures (e.g., a Phase I county may have developed an outreach program for the whole county) � y Evaluation and Assessment Reauirements • Evaluate program compliance ♦ Evaluate the appropriateness of BMPs ♦ Evaluate progress toward achieving Y measurable goals • Perform monitoring requirements if required by NPDES permitting authority (group ' monitoring projects are encouraged) 14 Record Keeping Re uirements ♦ Keep records required by NPDES permitting authority for at least three years ♦ Submit records when requested by NPDES permitting authority ♦ Make records and storm water management plan accessible to public , Reporting Requirements -. _ a. Submit annual reports to the permitting authority for first 5 year permit term 1 • In subsequent 5 year terms, submit reports in years two �gr ' and four, or more frequently if requested by permitting authority • Reports should include: ' — Status of compliance 1 " ` — Appropriateness of BMPs — Progress toward goals — Results of data collection/analysis — Summary of activities taking place in next term — Changes in measurable goals 15 �x Comply with TMDL Requirements - Ecology intends to link NPDES Phase II Requirements and Total Maximum Daily Loading(TMDL) • What is a TMDL? A TMDL is a calculation of the maximum amount of a `yx z pollutant that a waterbody can receive and still meet water quality standards and an allocation of that amount to the pollutant's sources. ' • Where are TMDLs Identified? — Under section 303(d)of the 1972 Clean Water Act, Ecology is required to develop lists of impaired waters that , do not meet state water quality standards. The law requires that Ecology establish priority rankings for waters on the lists and develop TMDLs , � - Comply with TMDL Requirements j ON! • What Renton water bodies are currently listed on the 303(d) list? t — Springbrook Creek — Green/Duwamish River h - — May Creek — Cedar River t. — Lake Washington. • What are the water quality standards violations? , — Fecal Coliform — Temperature — Dissolved Oxygen — Metals. 1 16 ' 1 Comply with TMDL � . . Requirements ' etc ' ♦ How will TMDLs Affect Renton? — The City will be required to comply with more stringent requirements beyond the six Minimum Control Measures as identified in a TMDL — No TMDL's have been established yet for these ` water bodies, but Ecology will be developing them in the near future. Ecology is currently conducting a scoping process for developing TMDL's in WRIA 8 and 9. 1 -� Washington State - NPDES Phase 11 Permit Process f fr ♦ NPDES permitting authority(Ecology) will implement the GENERAL Permit process ♦ Ecology issues draft general permit, requesting tYt comments within 90 days (Ecology expressing ' difficulty meeting deadline) ,A ♦ Ecology makes revisions and issues final permit °i- ♦ Municipalities or others seeking coverage under the Y General Permit submit a Notice of Intent(NOI) to permitting authority I ♦ Permitee covered under General Permit within 48 hours unless notified by permitting authority 17 Washington State Permit Process- ESA/Puget Sound Plan y ♦ Ecology will consider Puget Sound Plan in establishing permit requirements ' — Basic and Comprehensive Programs w n ♦ Objective that Phase II permit be consistent with ESA objectives r ♦ USEPA,NMFS, and USFS&WS can review and comment on Draft Phase II permit , ♦ Ecology's Phase II General Permit conditions for implementing 6 minimum measures is uncertain ' Stormwater Manual Options via �e7u; ,Y for City of Renton - Drivers NPDES Phase II permit Minimum Control Measure #5 requires post-construction stormwater management for new and redevelopment projects H Existing manual out of date and not equivalent to ' Ecology's SWMM NPDES Phase II - Ecology intends to require the SWMM or equivalent standards for General ' Permit 18 Stormwater Manual Options for City of Renton - Drivers st. Puget Sound Plan - Requires adoption of the SWMM equivalent standards a Project Permits (e.g. to obtain HPA WDFW ' requires development standards to meet SWMM) New construction disturbing > 1 acre requires :r a Construction NDPES Permit with a SWPPP prepared to standards equivalent to Ecology's ' Manual . � { x Stormwater Manual Options . . for City of Renton o tt u= 1990 KCSWDM 2001 Ecology Stormwater Management Manual for Western Washington (SWMM) k 1998 King County Surface Water Design Manual 5 (KCSWDM) revised to be equivalent to Ecology's Manual New City of Renton "Equivalent" manual 19 t Stormwater Manual: 1990 1 KCSWDM Not Recommended: r Standards out of date Not in publication City requiring more extensive requirements , #" through SEPA Other Agency permits could require use of , Ecology's Manual a Not equivalent to SWMM , 2� Surface Water Design Manual: 1998 1 # ` KCSWDM Revised to be Equivalent yyfx,' irg 1 ♦ Ecology has not approved the 1998 KCSWDM �k as Equivalent ♦ King County is updating 1998 Manual ♦ 1998 KCSWDM design standards are familiar to Engineers and Developers in King County ♦ Better suited for development review and , approval ♦ Development review process and some requirements are not consistent with City's 20 := Stormwater Manual: Develop } an Equivalent Manual ♦ Renton Manual Must Contain: s — Minimum Requirements Thresholds and Definitions — BMP Selection and Site Planning Processes f — Types of BMPs and Design Criteria ' - — Exceptions Process ♦ Potentially costly and staff intensive option with an uncertain outcome due to equivalency negotiation with Ecology w Stormwater Manual: x r Typical Contents ^�WCY H ♦ Plan Submittal Requirements ♦ Operations and Maintenance • Construction temporary Erosion requirements 4 and sediment Control ♦ Requirements to maintain Requirements drainage patterns ♦ Conveyance System • Protection of critical areas requirements • Offsite Analysis i • Flow(quantity)control • Coordinate with requirements q Basin/Watershed Planning ' • Runoff Treatment(water quality) • Requirements for Financial requirements Guarantees and Liability • Source Control(BMP) • Exemptions ' requirements 1 21 Stormwater Manual:Unique Features for City of Renton Any adopted manual will need to be modified to reflect unique City needs: • Special standards in Aquifer Protection Area • Direct Discharge to Lake Washington (no detention required) • Direct Discharge to Cedar River (requires , Ecology approval) a Development permitting process and plan ' submittal requirements Maintenance and Operation Requirements , E Y W �.- I Summary — Complying with t NPDES Phase 11 � t s.a ° Conclusions � • The Clean Water Act Requires Renton to implement a �? h program that complies with the NPDES Phase II program for MS4s ♦ The Department of Ecology is the NPDES Phase II �. permitting Authority in Washington • The EPA has established Minimum Control Measures required in the NPDES Phase II permit, but Ecology , can add new or strengthen requirements • NPDES Phase II regulations will effect construction projects that disturb >_ 1 acre of land • NPDES Phase II regulations will affect many City ' projects, programs, activities and operations 22 Summary Complying with � M NPDES Phase 11 Continued ' • The NPDES Phase II regulations allow Ecology to establish ' - standards for post-construction stormwater controls for new u. and redevelopment projects • Ecology will required the adoption of their Stormwater ' f Management Manual for Western Washington or equivalent standards ♦ Renton current stormwater design standards will have to ' change as a result of the NPDES Phase II regulations • Compliance with NPDES Phase II regulation will help to protect groundwater and surface water quality within Renton, benefiting public health and recreational uses along with ' habitat for fish and wildlife. 23 - .i - - ... t. I. _ t j .,. ,,{. ,7 t ( r - y J i ♦' f a t• :I,, y >. .!t . 't t, a R- ` r n^ _ .k J ; ;, s i " l J 7 r - t r t tI t ;,, i ' + v + -- % . .y 1 V'. 4 'n S F • - l f .y r1 t S' t nF s _ r t i i r t ' .l ,1; ( t.. .t ;t. _ t :C. .l' -� t t .1 - 1. tr y ( - Y , 2 1 j t f t 1 .. + ; t,� A 1.. .. - ` _ F _ • yam. + } r + > �k y t 5. \_ I. '. '. - n. - - r. ' 'r l 1. 'r' •. y Comparison of Ecology's 2001 ' = Stormwater Management Manual for Western Washington ' and 1998 King County Surface Water Design Manual F.� For City of Renton 1 Stormwater Manual: Comparison of minimum requirements for SWMM and 1998 KCSWDM Applicability and Exemptions - New Development r" SWMM: � _` ♦ All Projects-Erosion Control KCSWDM: IJ (plan not required,but BMPs must be considered) If between 2,000 and 5,000 sf of If between 2,000 and 10,000 sf ' new,replaced or new+replaced of new impervious surface is impervious surface is added or added and clears<2 acres or 35% 7,000 sf of land disturbance of site,Small Site Drainage — Site Plan Preparation Review Required(Single Family — Construction Site Erosion Only) control plan — Simplified Submittal — Source Control Requirements(does not ' = Preserve natural drainage require licensed engineer) location — Simplified Construction Site On-Site Stormwater Erosion Plan Management(flow control — Flow control(roof downspout with roof downspout controls/ controls/dispersion soil BMPs) ' 1 Stormwater Manual: Comparison of minimum ' requirements for SWMM and 1998 KCSWDM Applicability and Exemptions - New Development SWMM: KCSWDM ♦ if>5,000 sf of new impervious ♦ If adding>5,000 sf of new surface is added or 3/4 acres impervious surface(or 2,000 sf ' "+ native vegetation to lawn or 2.5 in a landslide hazard area)all acres native vegetation to core requirements and applicable ` pasture,additional minimum special requirements apply ' requirements apply — Offsite Analysis Runoff Treatment — Flow Control Flow Control (detention/infiltration) 1 (infiltration detention) — Conveyance System Operations and Maintenance — Erosion and Sediment Control If applicable, — Maintenance and Operations — Wetlands Protection — Water Quality treatment , — Basin/Watershed Planning If applicable, Other Adopted Area-Specific Requirements zx' Stormwater Manual: Comparison of minimum requirements for SWMM and 1998 KCSWDM t = Applicability and Exemptions - New Development SWMM: KCSWDM If applicable(Cont..) •*r Floodplain/floodway Delineation Flood Protection Facilities Source Control. , ,. Oil Control s;+ • If>50 acres,requires complex review ' 2 ' Stormwater Manual: Comparison of minimum requirements for SWMM and 1998 KCSWDM '- Applicability and Exemptions - Redevelopment ' SWMM: KCSWDM: ' • New,replaced or new+replaced ♦ Redevelopment projects with>_ impervious surface regulated $500,000 of site improvements ' same as new development that create>_ 5,000 sf of • Replaced imp.surfaces, contiguous new and/or replaced t treatment/flow control if: PGIS impervious surfaces — proposed total improvements requires full drainage review(all value>50%of existing core and applicable special improvements assessed value requirements) — for roads,new impervious> 5,000 sf and total of new+ replaced impervious area > ' 501/o of existing impervious area Stormwater Manual: Comparison of minimum requirements for SWMM and 1998 KCSWDM Applicability and Exemptions - Redevelopment '> SWMM: KCSWDM: U • If runoff from redevelopment is ♦ Redevelopment projects costing not separated from other areas of >$100,000 in a high-use site site,treatment facilities must be requires Targeted Review ' sized for entire flow — Source Control • Otherwise, standards are only — Oil Control applied to the portion of the site 't that is being redeveloped 3 f Stormwater Manual: Comparison of minimum ~ requirements for SWMM and 1998 KCSWDM ISOMR #1 Preparation of Stormwater Site Plan c r SWMM: KCSWDM ♦ Contents includes: Project . General content is similar to , Overview,existing conditions Ecology }� u• summary,off-site analysis, ♦ Format and required organization permanent Stormwater control is more clearly defined r plan,special reports and studies, ' other permits,operations and ,,. maintenance manual,bond quantities worksheets,and ' construction stormwater pollution prevention plan q Stormwater Manual: Comparison of minimum ' � ;r requirements for SWMM and 1998 KCSWDM MR #2 Construction Stormwater SWPP r{ SWMM: KCSWDM(Core Requirement#5): • SWPP must contain 12 elements ♦ TESC requirements are similar to z including: Mark clearing limits, Ecology _ establish construction access, ♦ TESC requirements for small control flow rates,install projects are simplified sediment controls,stabilize soils, ♦ Manual contains a detachable protect slopes,protect drain appendix with TESC tom° inlets,stabilize channels and standards/requirements that outlets,control pollutants, facilities use in field control de-watering, 30, maintenance,and management of A. From October 1 T AprilESC controls the construction project more restrictive T (may not be as restrictive as Ecology) ' 4 ' Stormwater Manual: Comparison of minimum r requirements for SWMM and 1998 KCSWDM { MR #2 Construction Stormwater SWPP ' SWMM: KCSWDM(Core Requirement#5): ♦ TESC supervisor to be specified, • From October I to April 30, but not necessarily a certified =z clearing only permitted if shown professional that silt laden water will not leave site ♦ Certified professional in TESC ' shall be identified for all projects 'y {fl and be on call Stormwater Manual: Comparison of minimum •� requirements for SWMM and 1998 KCSWDM J.: MR #3 Source Control of Pollutants SWMM: KCSWDM(Special Requirement#4) ♦ Applies to all projects ♦ Manual references a separate. • Intent is to prevent Stormwater document,the 1995 King County from coming in contact with Stormwater Pollution Control pollutants Manual as code • Includes guidance for A. Standards are similar implementing operational and ' structure source control BMPs based on business types(using SIC code) ♦ Source control BMPs are divided into applicable"mandatory"and "recommended" ' 5 IN- Stormwater Manual: Comparison of minimum requirements for SWMM and 1998 KCSWDM MY MR #4 Preservation of Natural Drainage x _ SWMM: KCSWDM(Core Requirement#1) ♦ Natural drainage patterns shall be ♦ Requirement is similar to , maintained to maximum extent Ecology's possible ♦ An additional provision is ♦ Special requirements are defined included to address landslide ' whether no conveyance system hazard areas(shown on maps q exists at the adjacent included in manual)and may downgradient property include tightlining a pipe system through downstream property , Stormwater Manual: Comparison of minimum ;} ,� •. requirements for SWMM and 1998 KCSWDM MR #5 On-site Stormwater Management _ �5 SWMM: KCSWDM: !3 s" ♦ Smaller projects meeting ► Comparable requirements is for a threshold require roof downspout smaller projects to meet 4 $' controls and soil quality BMPs to requirements of"Small Site , {`~ infiltrate,disperse and retain Drainage Review". These runoff to maintain hydrologic requirements are detailed in a y characteristics detachable appendix to the ♦ Type of dispersion/infiltration manual to allow easy reference , depends on lot size and soil on site. c characteristics ► Requirements are similar to ♦ Soil amendments required in Ecology's except there is no ' j' areas disturbed by activities and requirement for soils to be not planned for impervious amended surface ♦ Additional requirements may be ♦ Low impact development necessary if in a designated guidance is recommended(not landslide hazard zone required) 6 Stormwater Manual: Comparison of minimum .:r requirements for SWMM and 1998 KCSWDM MR #6 Runoff Treatment ' SWMM: KCSWDM(Core Requirement#8): a • Runoff Treatment required if>_ • Runoff Treatment required if 9 total effective PGIS is>_5,000 sf, 5,000 sf of new PGIS is added,or or if the total PGPS>—3/4 acre if>:5,000 sf of contiguous PGIS ' ' °" j • Treatment facilities and design (new and/or replaced)is created as part of a redevelopment x standards assumed to meet the requirement of state law to project,or if >_1.0 acre of --^^ provide all known available and contiguous PGPS will be added or modified reasonable methods of treatment • Guidance is provided for • Treatment facilities are required selection of treatment facilities based upon on four area-specific based on site's physical factors treatment goals,depending on ' and pollutants of concern. project type and location. A map is included in the manual that specifies the required treatment facility menu ' Stormwater Manual: Comparison of minimum requirements for SWMM and 1998 KCSWDM MR #6 Runoff Treatment SWMM: KCSWDM(Core Requirement#8): • Infiltration generally required if • Treatment facility menus basic, sites soils/physical criteria are Sensitive Lake Protection, l = met Resource Stream Protection,and • Basic Treatment: Sphagnum Bog Protection Direct discharges to Lake • Basic Treatment is 80%Total i Washington,non-fish streams, Suspended Solids Removal and infiltration(most ♦ Redevelopment projects only residential projects)�,..� P J ) require Basic Treatment Goal 80%Total Suspended ♦ Ecology has determined the Solids County standard is not equivalent ♦ Enhanced Treatment: (exemptions,requiring Basic for ' — Industrial,commercial,multi- redevelopment,and designating family,and roads discharging Resource Protection Standard to to fish bearing streams and a much greater area) lakes ' — Goal is improved dissolved metals removal 7 �- Stormwater Manual: Comparison of minimum requirements for SWMM and 1998 KCSWDM 4> st MR #7 Flow Control SWMM: KCSWDM(Core Requirement#3): Standard:Match predevelopment • Standard:Area specific flow ' flow duration for rates from 50% control standards are established of 2-yr flow up to 50-yr flow. and identified by a map within the Intent is to protect stream channels manual and include: from erosion — Level l:Match 2-and 10- yr - ♦ Method: Continuous runoff model predevelopment peaks (Western Washington Hydrologic (required where only Model) — protecting conveyance fr ♦ Predeveloped condition to be system) matched shall be a forested land Level 2: Level I plus match cover unless reasonable historic durations from 50%of 2-yr to information indicates the site was a 50-yr(same as Ecology) ' prairie(pasture)prior to settlement (required in areas sensitive to erosion,i.e.discharge to streams) Stormwater Manual: Comparison of minimum , requirements for SWMM and 1998 KCSWDM MR #7 Flow Control Nj SWMM: KCSWDM(Core Requirement#3): 31t — Level 3:Level 2 plus match ' r - 100-yr peak flow(required k where draining to severe flooding problems) • Method: Continuous runoff model, ' (King County Runoff Time Series- �r KCRTS) ♦ Predeveloped condition based on existing site condition , f' • Ecology has determined the County standard is not equivalent (make Level 2 default standard, assume"historic conditions"rather ' than existing site conditions,and some exemptions) 8 , Stormwater Manual: Comparison of minimum requirements for SWMM and 1998 KCSWDM ' MR #8 Wetlands Protection 1,4 ' SWMM: KCSWDM ♦ Objective is to ensure that wetland ♦ There is no separate requirement receive the same level of for projects draining to wetlands. ?' protection as other waters of the Alternatively,wetlands protection ' >- state is covered by sensitive area „ ♦ Applies to projects discharging ordinance and other core/special into a wetland,either directly or requirements indirectly through a conveyance ♦ Through Off-site analysis system requirements,downstream ♦ Discharges to wetlands shall wetlands can be identified and maintain the hydrologic conditions, level 3 detention required is hydrophytic vegetation,and considered a problem ' substrate characteristics. • Specific requirements are included ♦ Criteria is included to determine to protect Sphagnum bog wetlands requirements (generally uncommon) Bill E. Stormwater Manual: Comparison of minimum requirements for SWMM and 1998 KCSWDM .z MR #9 Basin/Watershed Planning xa SWMM: KCSWDM(Special Requirement#1 MIR •_ Objective is to promote watershed- Other Adopted Area-Specific 4 �y' based planning as a means to Special requirements) c develop and implement • The objective of this special comprehensive,water quality requirement is similar to .� protection Ecology's.: p Plans can include n ♦ Projects may be subject to Critical Drainage Areas,Master � F equivalent or more stringent Drainage Plan,Basin Plans,Lake ' requirements. Basin plans shall Management Plans,and Shared ` evaluate and include,as necessary, Facility Agreements. retrofitting urban stormwater BMPs into existing development and/or redevelopment in order to achieve watershed-wide pollutant ' reduction • The basin plan must be formally adopted by the jurisdiction and approved by Ecology ' 9 Stormwater Manual: Comparison of minimum requirements for SWMM and 1998 KCSWDM , MR #10 Operation and Maintenance SWMM: KCSWDM(Core Requirement#6) • Objective is to ensure that ♦ The objective of this special stormwater control facilities are requirement is similar to ' ` adequately maintained and Ecology's. `b operated properly. • An operation and maintenance ♦ Projects must prepare an operation manual and the responsible party and maintenance manual and the identified is to be included in the , responsible party identified. Technical Information Report, Guidance is provided for including a log of activity, k maintenance frequencies. available for inspection by the • A copy of the manual must remain county. A"Declaration of onsite and be transferred to new. covenant"must be recorded to property owners allow for inspection. ♦ In general,property owners are responsible for drainage facilities , maintenance,except for subdivisions where County may assume pond maintenance if certain conditions are met , Stormwater Manual: Comparison of minimum , requirements for SWMM and 1998 KCSWDM Optional Guidance In SWMM Manual . :, Optional Guidance"is considered guidance offered by Ecology as recommendations to local governments. Ecology considers their use to be in the best interest of the general public and the environment but will not make their implementation a requirement for manual equivalency. Two Optional ' a' Guidance are included +' �. " ,.,• • Optional Guidance#1 -Financial Liability - ♦ Optional Guidance#2-Offsite Analysis and Mitigation ' 10 , W,WA Stormwater Manual: Comparison of minimum ` requirements for SWMM and 1998 KCSWDM OG #1 - Financial Liability -{zc SWMM: KCSWDM(Core Requirement#7- �} • Financial liability relates to Financial Guarantees and Liability) erformance bonding/guarantees,p �g • This is a Core Requirement in the a ' • which is encouraged to ensure � manual. The objective of this proper construction of drainage special requirement is similar to r. facilities. Ecology's. p • Additionally,it is recommended • The manual includes twos specific that projects post a 2-year p guarantees,a Drainage Facilities financial guarantee for Restoration and Site Stabilization performance and maintenance of Financial Guarantee and a v; any drainage facilities that are Drainage Defect and Maintenance scheduled to be assumed by the Financial Guarantee(for those local government for operation and facilities that would be transferred maintenance. to county maintenance) • The objective is to ensure that projects have adequate funding to fully implement the stormwater control facilities. Stormwater Manual: Comparison of minimum d{,. requirements for SWMM and 1998 KCSWDM OG #2 - Off-Site Analysis and Mitigation SWMM: KCSWDM(Core Requirement#2- Offsite Analysis) • Recommendation that projects submit an offsite analysis report • This is a Core Requirement and ' that assesses the potential off-site requires a downstream analysis for 1/4 mile or where the project site water quality,erosion,slope p §' stability,and drainage impacts and area is less that 15%of the rs propose mitigation for those tributary area impacts ♦ 3 levels of analysis. The first is g,`` ♦ Recommends an initial qualitative qualitative and the second and analysis for up to a mile third level are more quantitative x downstream of the project and that • 3 classifications of downstream a quantitative analysis be required problems(conveyance system if additional information is needed nuisance, severe erosion and severe flooding). Projects must not significantly aggravate problems. Projects not required to fix or otherwise reduce the severity of problems,although doing so may be an acceptable mitigation. 11 Stormwater Manual: Comparison of minimum requirements for SWMM and 1998 KCSWDM �fr^ Adjustments SWMM: KCSWDM: ' • Adjustments to the MRs may be • The County manual includes an granted prior to permit approval Adjustment Process that is , .. and construction provided that a comparable to Ecology's findings of fact is prepared,that Adjustments and ' addresses the following: ExceptionsNariances. • The adjustment provides • The adjustment process is used substantially equivalent when a project proponent desires to environmental protection. vary from one of the core or • The objectives of safety,function, special requirements,or other environmental protection and requirements/standards contained facility maintenance,based upon in the manual. Several different sound engineering,are met. types of adjustments are used. 1 r � Stormwater Manual: Comparison of minimum ' a requirements for SWMM and 1998 KCSWDM Additional Provisions in KCSWDM x There is one Core Requirement and two Special Requirements included in the �a '! KCSWDM,but not included in the SWMM. • Core Requirement#4:Conveyance System-establishes design standards and requirements associated with the sizing of storm water conveyance systems such as pipes and open channels. The lack of a similar requirement and design t standards is a major disadvantage to adoption of the SWMM manual. a • Special Requirement#2: Floodplain/Floodway Delineation-includes a , requirement for projects containing or adjacent to a stream,lake,wetland,or closed depression to map the 100-year floodplain boundaries(and floodway)on the site improvement plans to minimize flooding impacts to new development and to prevent aggravation of existing flooding problems by new development. ' • Special Requirement#3: Flood Protection Facilities-includes a requirement for projects containing or adjacent to a Class I or 2 stream that have an existing flood protection facility or propose to construct a new or to modify an existing flood protection facility to analyze and/or design the flood protection facilities to conform with the Federal Emergency Management Administration (FEMA)regulations(44 CFR). 12 Stormwater Manual: Comparison of minimum f � requirements for SWMM and 1998 KCSWDM Status of KCSWDM ♦ County in process of updating Manual to be equivalent to SWMM(1 to 2 years away) • King County Manual update is being done as part of King County's Critical Area Ordinance update required by GMA. Public review to start in early 2003 and changes must be adopted by December 2004. • County also intends to have manual be consistent with ESA 404(d) requirements Ant n Stormwater Manual: Comparison of minimum requirements for SWMM and 1998 KCSWDM Advantages and Disadvantages SWMM-Advantages KCSWDM-Advantages >r , . ♦ Positions City to be compliance • more consistently used by City and cry r 1. w with NPDES Phase lI with relative developers and thus would reflect ' ease easier transition ♦ The standards for projects ♦ more of"cookbook"and includes a requiring regulatory permits will better description of the not be in question development review • Provides a higher level of storm submittals/process water management that will protect • clearer submittal and BMP z water quality,reduce flooding and requirements for smaller protect fish and wildlife habitat. developments(between 2,000 and 10,000 sf) • Includes additional core/special requirements(conveyance /floodplain)and optional guidance (financial guarantees) • Contains more guidance/requirements in landslide areas 1� Stormwater Manual: Comparison of minimum . : 4 requirements for SWMM and 1998 KCSWDM Advantages and Disadvantages SWMM-Disadvantages KCSWDM-Disadvantages rr# • Increased flow control and runoff • Is not equivalent to SWMM at treatment standards will result in present and will be updated within f more facilities and larger facilities. 1 to 2 years z • Design manual is not as clear • At that time,it will likely have the "cookbook"as KCSWDM same quantity/treatment standards • The development review as the SWMM and therefore have x4 ` es as the submittals process is not covered the same disadvantages as well as KCSWDM SWMM } • Lower thresholds will require more • manual applies flow/treatment drainage reviews and permit control based on"geographic inspections. maps"and City would have to develop maps or amend by other means ♦ Renton's development review process is different from King County's Stormwater Manual: Comparison of minimum ;444 ; r � requirements for SWMM and 1998 KCSWDM Other Options t { ♦ Wait and see how Phase I communities develop equivalent plans(e.g.,Seattle, King County) ♦ Adopt 1998 KCSWDM with revisions to make it equivalent to Ecology's ' ? SWMM — Set the default flow control standard at King Co.'s Level II and assume the natural land cover condition; — Require use of King Co.'s"Resource Stream Protection Menu"for the same Ecology a f instances that lies its Enhanced Treatment Menu; Ado gY PP " " t the P 2,000/7,000 sq.8.thresholds for the application of what King Co.has/will have that are equivalent to Ecology's Minimum Requirements 1 -5. — Adopt a redevelopment requirement similar to Ecology's 14 ' Appendix B QUESTIONS AND ANSWERS ' FROM ECOLOGY AND KING COUNTY ' %001159 )3l5 12'37/03 Appendix B QUESTIONS AND ANSWERS ' FROM ECOLOGY AND KING COUNTY ' Questions and Answers Received from Ed O'Brien, Department of Ecology on March 18, 2002. ' Question 1: The City of Renton is looking at adopting either Ecology's Stormwater Management Manual for Western Washington or King County's 1998 Surface Water Design Manual (and subsequent changes made by the County to make it equivalent). ' Does Ecology have a recommendation as to which manual the City should adopt and why? ' Answer: If you adopt the '98 King County Manual now, you will have to also do another update when they update that manual to be equivalent to Ecology's. Presently, it is not equivalent to Ecology's 2001 manual. The '98 King Co. manual is an ' improvement over the Ecology '92 manual. So it would represent an incremental improvement for you. However, note that King Co. applies its treatment and flow control requirements based on geographic area. They have not mapped recommended ' treatment and flow control for incorporated areas. So, merely adopting the King Co. manual does not identify treatment and flow control requirements for your constituents. You have to take that extra step. If you want to ' adopt the '98 King Co. manual now and minimize the changes that you will have to make from that to the new Ecology manual, here are some suggestions: Set your default flow control standard at King Co.'s Level II and assume the natural ' land cover condition; Require use of King Co.'s "Resource Stream Protection Menu" for the same instances ' that Ecology applies its "Enhanced Treatment Menu;" Adopt the 2,000/7,000 sq. ft. thresholds for the application of what King Co. has/will have that are equivalent to Ecology's Minimum Requirements 1 - 5. ' Adopt a different redevelopment requirement. King Co.'s is not equivalent. However the Tri-County ESA proposal may be. Of course, you can choose to wait for King Co. to make adjustments and then adopt ' what they have. The advantage of adopting the King Co. manual is there would be less confusion with engineers, builders, and developers. They would become ' accustomed to using one set of standards in unincorporated areas and in incorporated areas (if other cities also use the King Co. manual). The only issue I see there is that you are subject to King Co.'s timing in publishing an equivalent manual. If Ecology ' and King Co. have a disagreement, that may delay any equivalency decision, and you would be legally hanging-out with King County. 1 ' X001159_3335 12/2 i/02 Appendix B ' Question 2: Is Ecology going to require as a condition of the NPDES Phase II permit ' that the 2001 Stormwater Management Manual for Western Washington or equivalent standards ' be adopted? Would adopting the King County Manual satisfy this 1 requirement? Answer: If you attended a manual workshop, you should have heard that the issue of whether the phase II permit will require adoption of the Ecology manual, or an ' equivalent manual, will be the subject of public input in the permit development process through this year. If it is a permit condition, and if King Co. updates its manual to be equivalent to ecology's, then use of King Co.'s manual would satisfy the ' permit condition. Question 3: If Ecology is going to require the use of the Stormwater Management ' Manual for Western Washington or equivalent standards in the NPDES Phase II permit, are the NPDES Phase I permittee's currently required to meet the same standard? If yes, then what is the status of the Phase I permittee's complying with this ' requirement? Answer. The phase I.municipal stormwater permit is up for reissuance. Ecology intends to require the Phase I municipalities to update their manuals to Ecology's 2001 ' manual. Again, that will be subject to public input and hearings through the permit development process, so I cannot say that it will be a permit requirement. The current permit requires them to adopt a manual equivalent to Ecology's '92 manual. All but ' Tacoma and Pierce County have done that. Question 4: A potential issue with adopting King County's manual is that permitting , agencies may specify on permits that the work must comply with the Ecology Manual. In these situations, does Ecology believe that permitting agencies will consider King County's to be equivalent? ' Answer. We cannot guarantee what other agencies with a permit jurisdiction will do. Ecology will make it clear that in regard to stormwater management, if it makes a determination that a local government manual is equivalent, that it recommends that ' the local manual be accepted by other state and Federal agencies. Question 5: Do any jurisdictions already have an Ecology approved equivalent ' manual to the 2001 Stormwater Management Manual for Western Washington? Do you know of any jurisdictions that are in the process of adopting the August 2001 Stormwater Management Manual for Western Washington?. ' Answer: No. No. Question 6: Is it possible that the extent of some of the requirements be reduced as ' Ecology goes through the process of both determining the exact NPDES Phase II requirements as well as negotiating the NPDES Phased permits? Answer: Yes. See responses #2 and #3 above. It is likely that the Ecology manual ' will undergo some changes. Ecology already knows of some edits that need to happen to have it say what was intended. It is important that any changes occur before it gets referenced in a phase I or II permit (assuming that will happen, which is unclear at this ' time - see above). If it is incorporated into permit conditions, Ecology will likely not be able to make any substantive changes in the manual without doing a formal NPDES B-2 R. W. Beck X001159_3335 12/27/02 , ' QUESTION AND ANSWERS FROM ECOLOGY AND KING COUNTY ' permit amendment. That is a cumbersome process. So, if any of the phase I or II municipalities want to make arguments for changing what is in the 2001 manual, they ' should do it as soon as possible, or at least as part of the permit development process.. It is also a possibility that the manual guidance stays unchanged, but that the permit does not read the same as the guidance. This could occur for instance where there is a ' statement in the manual that Ecology does not think is appropriate or enforceable in an NPDES permit, but still makes sense for protecting the natural resources. ' Question 7: We want to confirm that Minimum Requirement # 2 - Element 12 requires a certified TESC professional to be identified and "on-call" for "every" project w/>2000 sf'. Is this required for equivalency? Answer: Yes. Yes. Question 8: What is the rationale for requiring all projects with> 5,000 sf to meet all ' 10 minimum requirements, but then not require detention unless the project creates > 10,000 sP Wouldn't most project creating between 5,000 and 10,000 sf need to provide detention anyway because they would produce> 0.1 cfs increase in flow? ' Answer: The 5,000 sq. ft. threshold exists because that is the smallest size project at which it may be reasonable to apply treatment facilities. It is used as the common trigger for further review of projects in regard to treatment or flow control. The extra set of thresholds that are within the treatment, flow control, and wetlands requirements are necessary because though the initial threshold is exceeded, it still may be not _reasonable or it may be counterproductive (in the State's opinion) to apply treatment or ' flow control facilities depending upon the specific circumstances of the project. The 0.1 cfs increase in flow should correspond to each of the size thresholds in ' Table 2.2 for areas using the Sea-Tac rainfall gauge without significant adjustments. For instance, a 10,000 sq. ft. new impervious area should cause a 0.1 cfs increase in the 100 year flood frequency for conversion from till forest. At the workshops, I have said that if local governments want to change the size thresholds so that they correspond to whatever triggers the 0.1 cfs increase, Ecology would be open to that. X001159_3335 12/27/02 R. W. Beck B-3 Appendix B ' Questions and Answers Received from Curt Crawford and Kelly Whiting of King County Department of Natural Resources on February 27" and 28",2002. Question 1: Is King County required to adopt Ecology's Stormwater Management , Manual for Western Washington or equivalent standards as a condition of the County's current or pending revised NPDES Phase I permit? ' Answer: Yes. According to the language of our current permit, we are required to adopt the equivalent of any updates to the 1992 Ecology Manual. However, Ecology has not given us a compliance schedule for the latest updates, presumably because ' they making the updates a compliance requirement of the next Phase I permit, which they are currently in the process of drafting. The next permit is expected to have a compliance schedule of 12 months to adopt an equivalent manual. When this permit is ' finally issued is not clear but don't expect it until late this year at the earliest. Question 2: Which County minimum requirements were not considered equivalent by ' Ecology and what is,being done to address this? Are there some differences between the minimum requirements where the County has been able to convince Ecology that the County's is equivalent? ' Answer: The current King County Manual was never deemed equivalent with the 1992 Ecology Manual primarily because it did not include a requirement for flow control facilities on redevelopment projects. This will be changed in our next update ' of the King County Manual. Attached on Table B-1 is a summary of key changes planned for the King County Manual to make it equivalent with the August 2001 Ecology Manual. ' Question 3: When will such changes become official for the County manual? Will the County issue a new manual or amendments? ' Answer: The County is currently drafting revisions to the Surface Water Design Manual to make it equivalent with the August 2001 Ecology Manual. Our current plan is to complete a draft of Chapter 1 revisions in March and make it available for ' stakeholder review. After that, we plan to have a full draft available in July, when the Executive plans to submit legislation to our Council for this and other regulatory updates related to the ESA 4(d) Rule. When the updated manual is actually adopted is ' anyone's guess (anywhere from 6 to 18 months.after submittal). Question 4: •A potential issue with adopting King County's manual is that permitting ' agencies may specify on permits that the work must comply with the Ecology Manual. What does the County do to address is potential issue? Answer: I presume you're talking about WDFW's practice of requiring compliance ' with the Ecology Manual through HPAs. We have had this same problem and will continue to have it until our manual is approved by Ecology as equivalent. Until then, ' we will have to deal with both manuals on projects that require an HPA. I think that some of our roads projects have been modified on occasion to avoid doing work that requires an HPA. ' B-4 R. W. Beck X001159_3335 12/27i02 , QUESTION AND ANSWERS FROM ECOLOGY AND KING COUNTY ' Question 5: Does the County envision any other future changes to the manual? Is the County considering adopting standards that exceed any of the standards in Ecology's ' 2001 Manual? Answer: The County is currently not considering any new standards that are more stringent than the standards in the 2001 Ecology Manual. We do, however, have some ' existing standards (e.g., those addressing flooding, conveyance, and landslide hazard issues) that are not included in the Ecology manual because of its focus on water quality protection. Also, as we complete stormwater plans that are expected to be ' required by the next permit, we may find that the new Ecology standards need to be increased in certain subbasins in order to meet Clean Water Act objectives for stormwater discharges. We may also find that these standards can be reduced in ' certain subbasins. Question 6: Based upon the Summary of Key Changes Needed (Table B-1), it sounds ' like the County is planning to continue to use the KCRTS model with some changes to require that predeveloped conditions are forested and Level 2 flow control will be the default standard. Will this be a change in the manual only or will the model be ' modified also? I assume you are not planning to switch to the Ecology Model. Would you accept the use of either the KCRTS or the Ecology WWHM?. Answer: You are correct that we plan to continue using KCRTS. -I have not ' evaluated the latest WWHM model, so am not sure how well their facility sizing routines are coming along. We will probably consult our permit reviewers before deciding on how to deal with projects designed using WWHM. Technically, the ' results from the two models should be very similar. None of the proposed changes to our standards require a change to the KCRTS ' program. We intend to keep KCRTS flexible in terms of analysis assumptions. However, we are considering dropping the reduced 8-year records. With the Level 2 standard there is not much advantage in keeping the reduced records. We may add in some additional features such as an import/export utility to allow KCRTS to talk with WWHM and other models. Not much budget for these types of things though. In addition to answering the above questions, the following summary of key changes ' proposed for the manual update to achieve equivalency were provided. ' X001159_3335 12/27/02 R. W. Beck B-5 Table B-1 KING COUNTY SURFACE WATER ' DESIGN MANUAL — 2002 UPDATE SUMMARY OF KEY CHANGES NEEDED — 2/25/02 Drainage Review Thresholds 1. Reduce the 5,000 square-foot threshold for new impervious surface to 2,000 ' square feet. 2. Add a threshold for capturing projects that create 35,000 square feet of new pervious surface. 3. Add a threshold for capturing transportation redevelopment projects in which new impervious surface is 5,000 square feet or more and totals 50% or more of the ' existing impervious surface within the project limits. 4. Eliminate the threshold for capturing redevelopment projects which spend more than $500,000 and replace it with a threshold that captures non-transportation ' redevelopment projects in which the total of new plus replaced impervious surface is 5,000 square feet or more and for which the valuation of proposed improvements (including interior improvements and excluding required mitigation improvements) exceeds 50% of the assessed value of the existing site improvements. Core Requirement #3: Flow Control 1. Make Level 2 Flow Control the default flow control facility standard everywhere except where discharge is to a "major receiving water" via a manmade conveyance system that is not subject to erosion. This will be done by expanding Level 2 Flow Control Areas on the Flow Control Applications Map. 2. Change the Level 2 Flow Control Standard to assume "historic conditions" rather than "existing site conditions" for determining release rates. 3. Add language that requires a flow control mitigation of both new plus replaced impervious surface on redevelopment projects. 4. Modify the basic Impervious Surface Exemption 1 to address redevelopment projects and to reflect lower thresholds for some form of flow control (i.e., a ' facility or BMPs). Eliminate the current impervious surface and peak flow exemptions (Exemptions . 2 and 3) for projects located in Level 2 Flow Control Areas. Replace them with a threshold or exemption that waives the Level 2 facility ' X001159_333 5 12/27/02 Table B-1 5. requirement if there is less than a 0.1-cfs difference in the sum of 100-year peak flows for those developed surfaces required to be mitigated and the sum of 100- year peak flows for the same surfaces assuming Puget Sound predevelopment , conditions 6. Eliminate the 0.4-cfs exemption for urban redevelopment projects (Exemption 4) that are located in Level 2 Flow Control areas. 7. Modify the forested open space exemption (Exemption 5) to allow the flow control facility requirement to be waived for any development if the runoff from new developed surfaces is "fully dispersed" within an onsite drainage area that is 65% or more forested open space. R. Eliminate Lake Meridian and Lake Sawyer from the "major receiving waters list" ' under the Direct Discharge Exemption 6 if they become Level 2 Flow Control Areas. ' 9. Eliminate the discretionary exemption for infill projects (Exemption 8) that are located in Level 2 Flow Control Areas. 10. Add an exemption or threshold which allows the facility requirement or standard t to be reduced if a plan or study approved by the County identifies or demonstrates that a lesser standard is sufficient to protect water quality and habitat functions essential to salmonids. ' Core Requirement #8: Water Quality 1. Modify the Surface Area Exemption 1 to reflect the new threshold (35,000 square feet) for new pervious surface and remove the "contiguous" allowance. ' 2. Modify the Cost Exemption for Redevelopment Projects (Exemption 2) to reflect the new thresholds for transportation and non-transportation redevelopment projects. ' 3. Modify the forested open space exemption (Exemption 3) to allow the water quality facility requirement to be waived for any development if the runoff from ' new developed surfaces is "fully dispersed" within a drainage area that is 65% or more forested open space. 4. Eliminate the exception for redevelopment projects that limits their compliance ' requirement to only the Basic WQ Menu. 5. Expand Resource Stream Protection WQ Treatment Areas to include both potential and designated Regionally Significant Resource Areas outside of the Urban Growth Area. This would essentially include most of rural King County. 6. Modify the Resource Stream Protection Menu threshold to apply this menu to ' only those projects in which new pollution-generating impervious surfaces will comprise more than 10% of an onsite drainage area that is located within a potential or designated Regionally Significant Resource Area. 2 R. W. Beck X001159_3335 12/27/02