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Planning ProceduresPLANNING PROCEDURES TO ADDRESS WATER QUALITY IMPACTS FROM DEVELOPMENT AND REDEVELOPMENT Dorothy Crawford, P.E., U.S. EPA Region 6 Municipal Permits Section Abstract The purpose of this paper was to guide Region 6's MS4 permittees in their efforts to develop appropriate Planning Procedure Elements for their Storm Water Management Program. Federal regulations required municipalities with populations over 100,000 who operating a separate storm sewer system to apply for a Municipal Separate Storm Sewer System (MS4) NPDES permit. Region 6 has received over 20 applications for MS4 permits. These applications were submitted in two parts. Part 1 presented background and general information about the MS4 and began to identify some sources of urban pollution. Part 2 built upon the foundation established in Part 1 and included the applicant's Storm Water Management Program. This Program was prepared by the applicants to achieve the Clean Water Act's goal for MS4 permits of reducing pollutants from MS4 discharges to the maximum extent practicable. Region 6 is in the process of developing these MS4 permits. The goal of the MS4 NPDES program is the reduction and elimination of pollutants in storm water discharges from urban areas. The application regulations (federal regulations 40 CFR 122.26(d)) were designed to meet this goal by requiring the development of site specific programs for the individual MS4s. Site specific permitting is crucial given the variables of urban runoff pollution causes and effects. The applicants were required to address in their SWMP the different categories of urban pollution sources (40 CFR 122.26(d)(iv)). These elements are considered the minimum requirements for the SWMP. Each element is unique and considered important to achieving the goals of the NPDES program. The discussion will be limited to the Development Planning Procedures SWMP element. This particular element has caused the applicants a lot of grief and confusion. The permittees are concerned about how Region 6 will interpret this regulatory requirement. During the review of the applications the Region has ''t ^' frequently noted that the Planning element was deficient as ;. submitted. We anticipate that many of the draft MS4 permits will contain compliance schedules for the permittee to enhance or 7`">I develop an appropriate Planning element. All It is important to note a common misunderstanding about the interrelationship between the Construction Program element and the Development Planning Procedure element. One potential aspect of the Planning element may involve the use of permanent runoff control devices such as ponds and basins, which can also function as sediment ponds the permittees may require under the Construction element. The permittees can also select to implement the two elements in the same way (e.g., by plan review), but the elements' have different missions. The Planning and Construction elements are unique from each other in that the Planning element addresses potential pollutants loading AFTER construction is complete, where the Construction element addresses pollutants DURING construction activities. The Flood Management element is also closely related to the planning element. Both address post construction water quality impacts of projects during the planning and designing stage. However the Flood Management element is limited to flood management projects while the Planning element addresses a much broader array of projects. It is not uncommon for local authorities to develop ordinances end design documents that address all three of these elements (Construction, Planning, and Flood Management) in one document. The MS4 permittees need to remain aware of the unique nature of each of the required elements. The following is the application regulation for the Planning element (40 CFR 122.26(d)(2)(iv)(A)(2)): "The applicant must include a description of planning procedures including a comprehensive master plan to develop, implement. and enforce controls to reduce the discharge of pollutants from municipal separate storm sewers which receive discharges from areas of new development and significant redevelopment. Such plan shall address controls to reduce pollutants in discharges from municipal separate storm sewers after construction is complete." EPA's guidance documents to help the applicants; interpret the regulatory requirements stated that a satisfactory Planning element would identify planning procedures and structural and nonstructural control measures for development and redevelopment projects to address water quality impacts after construction. The permittees planning element should document how proposed or existing ordinances and /or site design guidelines IMPACT the planning of sites to be developed or redeveloped to more satisfactorily address the proven storm water runoff pollution that results from urbanization. To put it in :simpler terms, as the land planner is putting pencil to paper to begin the concept of the development's layout how does the Planning element affect the land plan? As the design engineer develops the detailed plans for the development does the permittees' guidelines or { ordinances require special accommodations for post- construction storm water quality impacts from the project? Historically municipalities have instructed development professionals on all aspects of site planning, from lot dimensions to street right of way and sidewalk widths, to allowable land uses. It is generally recognized that zoning and planning requirements result in an overall benefit to a community. Many of these planning restrictions and guidelines have been developed to provide sufficient safety, and aesthetics for the public, and to allow publiccservicescsuch as water and sewer to be provided more efficiently. The SWMP's Planning element will assure that post- construction water quality is addressed during the planning stage along with other public services and aesthetic issues. The parties interested in this issue can exert powerful influences on the cities. Some of the Planning element's controls and practices are land intensive or costly. To a developer land is money. The more concentrated the placement of homes, buildings, and parking lots the more benefits the developers will realize from their efforts. Most cities expend financial resources to ATTRACT development and are concerned that any additional development controls will both detract from this effort and possibly make the playing field uneven between them and their to date unregulated neighbor communities. Then there is the issue of who pays to maintain these controls. Most municipalities do not eagerly await additional drains on their operating funds. The choice for the MS4 cities is NOT between developing or not developing, it IS between taking steps to ensure that suitable practices are implemented to mitigate development's adverse impacts on runoff, or the failure to take such steps. MS4 permittees need to go through a thought process before developing planning requirements. What are you requiring? Wh y are you requiring it. How and Who will be administrating the requirements? What are the expectations for the requirements? How should the cities select the planning procedures that are appropriate for them? As a starting point Region 6 would recommend answers; to the following questions be investigated: What are the pollutants in MS4's discharges? What are their water quality impacts? What are the pollutant sources? What are the array of known controls and their performance standards? What are the area's natural factors that limit options? The post- construction controls that abate pollution from areas that have been recently developed or redeveloped can be categorized into three general groupings (source, runoff, and treatment). Source controls can prevent the pollution generation or accumulation. In line with our national Pollution Prevention guiding principle Region 6 would encourage these controls be adopted wherever possible. It is frequently cheaper to prevent Pollution then to treat it. Runoff control abates urban pollution because devices designed to control flows often provide some level of pollutant removal such as sedimentation, and some urbanization water quality impacts can be traced back to increased quantity of runoff. Then there are the controls whose purpose is to treat the runoff and remove the pollutants prior to discharge. When developing the Planning element of the SWMP the permittees should investigate the existing technical information on urban runoff pollution controls. The science of controlling pollution in urban runoff is undergoing constant growth. New concepts to address this issue are constantly being developed. The act of assigning these controls to a category has an arbitrary aspect to it. Many of these controls have multiple facets to them. The gist of most of the source controls is to allow the development to lay lightly on the land, to minimize earth moving, to let the topography suggest the land use, and also to minimize the sources and causes of the pollution such as impervious surfaces, and standard drainage design principles that emphasize the rapid conveyance of runoff. Some of the source controls that we would recommend the MS4 permittees consider including in their Planning element are as follows. The possibility of requiring that natural drainageways be maintained wherever possible during the planning stage. Requiring the maintenance of post - development pollutant loadings from a site to pre - development levels. Placing a numeric limit on the percentage of allowable impervious surfaces in a developed area. Require modular or porous pavements for certain low use paved. surfaces such as a shopping malls remote parking areas, residential street parking and driveways, private roads, fire:lanes, and industrial storage yard and loading zones. Permittees should consider stressing surface drainage patterns over subsurface drainage patterns. Pervious surface drainage patterns help to both control the increased volume and rate of runoff from urbanized areas, and increases the potential of pollutant removal from surface vegetation. Promote the use of filter strips and the elimination of curbing where appropriate. Ordinance can require the maintenance of existing vegetation for land of a set slope, and the establishment of new vegetation. Land planning could be encouraged that does not emphasis vehicle Use. There are examples of developments across the country that have been planned with the intent to promote pedestrian and non - motorized travel for day to day activities (community based development, public transportation) . The runoff' control category is the one most people think of when considering planning procedures for development tha water quality. t address The use of the various types of detention devices (dry and wet basins, and man -made wetlands) is dependant on the areas climate and soils, among other things. It is commonly believed that 90% of an urbanized areas pollution results from the more frequent small rainfall events and from the first flush of runoff. Detention devices designed for the larger less frequent catastrophic storm events may provide very limited effective pollutant removal unless special considerations are given to the issue during design. A basin designed exclusively to detain the 25 year storm event to prevent flooding would typically not provide effective Pollutant removal. However if the basin's design incorporated internal flow delaying devices and outfall controls specifically designed to retain the more frequent storm events flows the basin might function as an effective Pollutant removal device. Unless combined with some sort of discharge treatment system or an aggressive surface cleaning program, pavement and rooftop detention would not typically function to effectively remove pollutants. This detention does have the Potential of decreasing the downstream runoff rate which may provide some relief from sediments created by erosion. In. addition for smaller events the delayed release of flows may impact the ability of downstream surface vegetated conveyance ;systems to remove pollutants from the discharge. Treatment options may be necessary where existing conditions prohibit a lot of the source and runoff control devices and practices. Treatment may also be necessary to address certain Pollutants that are not abated by the previous two categories of controls. Examples of this are dissolved metals and toxics. Recent research has indicated that treatment may be the best control mechanism. for these parameters. Treatment controls typically have the advantage of being non -land intensive. We would recommend that planning requirements allow planners the option of treating the runoff in lieu of utilizing the source and runoff control devices and practices. Coastal areas may need to address floatables more directly than via education and litter programs. Requiring screening of discharges from developments known to produce excessive floatables may be more effective. Infiltration is also an effective runoff control mechanism. Devices in this category range from porous pavements, to infiltration trenches, to vegetated ditches with berms. The use of flocculants has been used to pretreat runoff flowing into man -made wetlands. Disinfection of runoff is specific to the problem of bacteria. Separators may be appropriate for runoff discharges from areas known to produce high levels of oil and grease such as gas stations, truck terminals, and bus depots. The permittees Planning element should include policies, ordinances, zoning, or other instruments (or schedules to develop them) as necessary to communicate the Planning element requirements to the planning and design community. We would recommend the element contain design criteria wherever possible (e.g., percent impervious surface allowable, maintenance of pre /post pollutant loadings, detention of first inch of runoff). The element must include a discussion of how the permittees intend to enforce and implement the requirements. Flexibility is an important part of the equation. The permittees should allow developers and planning professionals the leeway to select the form of control most appropriate to the site. Region 6 recommends emphasizing the source controls over the treatment controls. Special considerations should be provided to environmentally sensitive areas (e.g., wetlands, coastal areas). Due to the fact that many of the MS4 cities are already built up and new development planning controls may seldom be utilized, redevelopment should be addressed by the Planning element in addition to development projects. References: California Stormwater Quality Task Force (1993) ; California Storm Water Best Management Practice Handbook - Municipal. New York State Department of Environmental Conservation(1992); Reducing the Impacts of Storm Water Runoff from New Development. New York State Department of Environmental Conservation(1992); Model Storm Water and Erosion Control Ordinance. Pitt, Robert; Field, Richard; Lalor, Melinda; Brown, Michael; Urban Storm Water Toxic Pollutants: Assessment, Sources, And Treatability. Pitt, Robert; Barron, Patricia F.; Ayyoubi, ali; Field, Richard (1991) ; The Treatability of Urban Storm Water Toxicants. Schueler, Thomas R.; Mitigating the Adverse Impacts of Urbanization on Streams, A Comprehensive Strategy for Local Government. Schueler, Thomas R.; Kumble, Peter A.; Heraty, Maureen A. (1992) ; A Current Assessment of Urban Best Management Practices, Techniques for Reducing Nonpoint Source Pollution in the Coastal Zone. Novotny, Vladimir; and Olem Prevention, Identification, State of Florida Department Florida Development Manual, Management. Harvey (1994); Water Quality, and Management of Diffuse Pollution. of Environmental Protection; The a Guide to Sound Land and Water Terrene Institute (1994) ; Fundamentals of Urban Runoff Management, Technical and Institutional Issues. Virginia Department of Conservation and Recreation Division of Soil and Water Conservation (1990) ; Best Management Practices Handbook. Yu, S.L.; Kasnic:k, M.A.; and Byrne, M.R. (1993); A level spreader /vegetat.ive Buffer Strip System for Urban Storm Water Management. U.S. Environmental Protection Agency (1980) ; Porous Pavement, Phase I Design and Operational Criteria (EPA- 600/2 -80 -135). U.S. Environmental Protection Agency (1979) ; Demonstration of Nonpoint Pollution Abatement Through Improved Street Cleaning Practices (EPA - 600/2 -79 -161). U.S. Environmental Protection Agency (1992) ; Guidance Manual For the Preparation of Part 2 of the NPDES Permit Application for Discharges From MS4s (EPA- 833 -B -92 -002). U.S. Environmental Protection Agency (1993) ; Handbook, Urban Runoff Pollution Prevention and Control Planning (EPA- 625 -R -93 -004). U.S. Environmental Protection Agency (1990) ; Storm and Combined Sewer Overflow:An Overview of EPA's Research (EPA- 600 -8 -89 -054). U.S. Environmental Protection Agency (1994) ; Storm Water Pollution Abatement Technologies (EPA- 600 -R -94 -129). U.S. Environmental Protection Agency (1993) ; Guidance Specifying Management Measures For Sources of Nonpoint Pollution in Coastal Waters (EPA - 840 -B -92 -002).