Model Stormwater Ordinances

Transcription

1 Model Stormwater Ordinances Breakout Group 11 am to 12 pm Sadie Drescher Watershed Researcher & Planner Center for Watershed Protection April Turner Coastal Communities Specialist SC Sea Grant Consortium January 16, Charleston, SC Coastal South Carolina Low Impact Development Manual Funded by the National Estuarine Reserve System Science Collaborative

2 Center for Watershed Protection Non-profit 501(c)3, non-advocacy organization founded in 1992 Work with watershed groups, local, state and federal governments Provide community tools to protect lakes, rivers, streams, and estuaries 23 staff in Ellicott City, MD

3 Overview Discuss model ordinances Discuss local ordinance opportunities and challenges Review a few good SC ordinances Identify SC coastal community ordinance needs and resources

4 Outline Background Code and Ordinances Opportunities to improve Highlight SC Discussion

5 Land Development Impacts Urbanization not only has a direct impact on a site s natural resources, it also changes site hydrology and alters stormwater runoff characteristics These changes in stormwater runoff can have a number of negative impacts on on-site and downstream aquatic resources

6 Land Development Process Source: Planning with Power, Purdue University Source: Harford County, MD DPW

7 Coastal Stormwater Management Golf course in M. Beach to Spill way over rip rap to Intercoastal Waterway

8 Better Site Planning Stormwater Management Approach Structural Stormwater Management Practices Better Site Design Low Impact Development Practices Receiving Waters

9 Which is Better for Water Quality on a Watershed Basis? OR Low Density Higher Density

10 EPA Research on Smart Growth & Water Scenario A: 1 unit/acre Scenario B: 4 units/acre Scenario C: 8 units/acre Impervious cover = 20% Runoff/acre = 18,700 ft 3 /yr Runoff/unit = 18,700 ft 3 /yr Impervious cover = 38% Runoff/acre = 24,800 ft 3 /yr Runoff/unit = 6,200 ft 3 /yr Impervious cover = 65% Runoff/acre = 39,600 ft 3 /yr Runoff/unit = 4,950 ft 3 /yr

11 What is Better Site Design? Approach to new residential & commercial site design that seeks to: Reduce the amount of impervious cover Reduce the volume & rate of stormwater runoff Use pervious areas for more effective stormwater treatment Increase the natural lands set aside for conservation Achieve a marketable, cost-effective product

12 Codes and Ordinances

13 Common Obstacles Change is bad Misperceptions Costs Safety concerns Mosquitoes Marketability Maintenance Property Rights Liability Mindsets

14 Code and Ordinance Example from Shenandoah County, VA Limits LID B. All portions of stormwater management systems located along new streets shall be located underground and shall meet the requirements of Curb drop inlets shall be installed at street intersections and at such intermediate locations as required to collect surface water. Prohibits roadside stormwater management

15 Code and Ordinance Example from Frederick County, VA Limits LID The County Stormwater Management code ( and ) requires all drainage and grading be conveyed away from a building. The collection or concentration of water not in drainage easements is not allowed. No mention of LID in the County codes Prohibits LID no ponding on site Recommend language to allow LID onsite

16 Code and Ordinance Example from Shenandoah County, VA Same Old, Same Old. VDOT road width standards used for local roads Virginia Department of Transportation s Subdivision Street Design Guidance requires a minimum road width of 28 feet for curb and gutter road with less than 400 average daily trips. Prohibits retrofits and increases impervious cover

17 Code and Ordinance Example from Shenandoah County, VA Natural Conservation Not So Much No landscaping or tree protection ordinances that encourage planting or protect trees during development Does not encourage natural resource protection (e.g., tree preservation, land use conservation) No clearing & grading limits; not required on site plans Does not encourage planning ahead and site management

18 Code and Ordinance Example from Richland County, VA Code Conflict Richland County s Storm Drainage Design Standards Manual (2001), provides design criteria for grass swales, dry swales, and wet swales / wetland channels (Sec. 4.1). The County s BMP Manual contains design criteria for grass swales and bioretention swales (Sec. 5.6 and 5.7). Thus, open channel systems are available to local developers as an option for stormwater management in new development. Chapter 26 of the Richland County Code of Ordinances ( (b)(1)a) states that curb and gutters shall be installed on all paved roads unless the county engineer determines that another system is acceptable.

19 What existing resources do you use? Why? Why not?

20 Scale & Time Issues Local development rules State and Federal regulations Model development principles Permit cycles Post construction Long term maintenance, tracking and verification Incentives Let s review those codes..

21 Step 1 Identify And Conserve Natural Resources Meeting Natural Area Conservation Buffer Preservation Floodplain Protection Soil Conservation Preservation of Existing Topography Reduce Stormwater Runoff Step 2 Apply Better Site Design Techniques Open Space Design Reduced Clearing and Grading Limits Reduced Roadway Lengths and Widths Reduced Building Footprints Reduced Parking Lot Footprints Alternative or Fewer Cul-de-sac Reduce Stormwater Runoff Step 3 Apply Low Impact Development Practices Natural Areas and Buffers Natural Drainageways Simple Downspout Disconnection Rain Gardens Rainwater Harvesting Green Roofs Pervious Pavement A step by step approach to comply at a development site Meet RR Requirement? Step 4 Apply Structural Stormwater Practices Provide Additional Runoff Reduction Manage Resource Protection Volume Provide Flood Protection Meet Remaining Criteria? Step 5 Mitigate Unmanaged Impacts

22 Code and Ordinance Example from Mount Pleasant, SC Allow LID WATER QUANTITY CONTROLS. (9) Stormwater management facilities may include both structural and nonstructural elements. Natural swales and other natural runoff conduits shall be retained where practicable. (10) Where additional stormwater management facilities are required to satisfy the minimum control requirements, the following measures are examples of what may be used: (a) (b) (c) (d) Stormwater detention structures (dry basins); Stormwater retention structures (wet ponds); Facilities designed to encourage overland flow, slow velocities of flow, and flow through buffer zones; Infiltration practices. Nonstructural BMPs allowed; infiltration allowed; mentions volume control

23 Code and Ordinance Example from Georgetown, SC Allow LID (Ord. No , Div. 3, ) Sec Stormwater Management Facilities. (a)stormwater management facilities may include natural and man-made elements. Natural swales and other natural runoff conduits shall be retained to the maximum extent practicable. (b)where additional stormwater management facilities are required to satisfy the minimum control requirements, the following measures are examples of what may be used along with other measures subject to the approval of the Department: 1.Facilities designed to encourage overland flow, slow velocities of flow, and allow for sheet flow through buffer zones. 2.Infiltration practices. 3.Bioretention facilities. 4.Swales and filter strips. 5.Constructed wetlands. 6.Pervious paving technologies, including pervious concrete, asphalt and pavers. 7.Natural and vegetated buffers. 8.Stormwater detention structures (dry basins used for reducing peak discharge only). 9.Stormwater retention structures (wet ponds used for reducing peak discharge and reducing pollutant discharge). 10.Retention of natural landscape and trees in parking lots. 11.Other BMPs aimed at reducing the discharge of polluted stormwater.

24 Code and Ordinance Example from Georgetown, SC (cont d) Allow LID (Ord. No , Div. 3, ) Sec Stormwater Management Facilities. (c)where detention and retention structures are used, designs which consolidate these facilities into a limited number of large structures will be preferred over designs which utilize a large number of small structures. (d)when wet ponds are employed, retention/planting of littoral vegetation, particularly native wetland plants selected for nutrient and contaminant uptake capacity shall be included. (e)drainage plans can be rejected by the Department if they incorporate structures and facilities that will demand considerable maintenance and will be difficult to maintain, or utilize numerous small structures if other alternatives are physically possible. Outlines the LIDs allowed, pretreatment is required, and mentions MEP and minimum controls

25 Code and Ordinance Example Jasper County, SC Do BSD & Allow LID Stormwater Design Manual, 2011

26 Jasper County, SC (cont d) Stormwater Design Manual, 2011

27 Jasper County, SC (cont d) Innovation and Flexibility Stormwater Design Manual, 2011

28 Code and Ordinance Example from Charleston County, SC Must Meet Local Protection Standards Sec Design and engineering standards The public works director is authorized to develop and adopt policies, criteria, specifications, and standards for the proper implementation of the requirements of this article, federal and state laws and the SWMP; and to provide a sound technical basis for the achievement of stormwater management, including water quality and quantity objectives. These standards may be provided in the manual. Sec Charleston County Stormwater Program Permitting Standards and Procedures Manual (manual). (c)hydrologic, hydraulic, and water quality design criteria (i.e., design standards) for the purposes of controlling the runoff rate, volume, and pollutant load. Suggested reference material shall be included for guidance in computations needed to meet the design standards; (d)information and requirements for new and redevelopment projects in special protection areas necessary to address TMDLs, known problem areas and other areas necessary to protect, maintain, and enhance water quality and the environment of Charleston County and the public health, safety, and general welfare of the citizens of Charleston County.

29 Code and Ordinance Example from Hilton Head, SC Encourage Practices Pond Shorelines. Detention and retention ponds shall be designed so that shorelines are meandering where possible, rather than straight, to increase the length of shoreline, thus offering more space for the growth of littoral vegetation for filtering purposes. Bank Stabilization. Where cleared site conditions exist around detention or retention areas, the banks shall be sloped to the proposed dry weather water surface elevation and planted for stabilization purposes. Where slopes are not practical or desired, other methods of bank stabilization will be used and noted on plans submitted for approval. Use of Wetlands. The use of wetlands for storing and purifying runoff is strongly encouraged. However, care must be taken not to overload their capacity, thereby harming the wetlands and transitional vegetation. Regulated wetlands shall not be disturbed by the construction of detention ponds in them or sufficiently near to deprive them of required runoff or to lower their normal water table elevations. Adjacent detention ponds that benefit from retention of normal wetland water table elevations are acceptable. If a retention or detention pond is going to be located near a regulated wetland, the applicant will provide data showing that impacts will not be detrimental to the wetland Increase vegetation, stabilization, and wetland use

30 Code and Ordinance Example from Horry County, SC Landscape Plan Under Plan Requirements, Stormwater management and sediment control plan. To improve the aesthetic aspects of the drainage system, a landscape plan for all portions of the drainage system shall be part of the stormwater management and sediment control plan. This landscape plan shall address the following. a. Tree saving and planting plan. b. Types of vegetation that will be used for stream bank stabilization, erosion control, sediment control, aesthetics and water quality improvement. c. Any special requirements related to the landscaping of the drainage system and efforts necessary to preserve the natural aspects of the drainage system. d. Landscaping shall not be installed within the easement unless it is a part of the drainage system (for example low impact development). Supports conservation, native plantings, and using plants for ESC, stormwater

31 Code and Ordinance Example from Hilton Head, SC Specify Use and Allow LID ARTICLE VI. - STORMWATER MANAGEMENT STANDARDS- Direct Stormwater Discharges. Channeling runoff directly into natural water-bodies from pipes, curbs, lined channels, hoses, impervious surfaces, rooftops or similar methods shall not be allowed unless methods of filtration are provided. Instead, runoff shall be routed over a longer distance through sheet flow, swales, drywells or infiltration ditches and other methods to increase percolation, allow suspended solids to settle and remove other pollutants. Chapter 6 Natural Resource Protection: Sec Creation of Wetland Systems The creation of wetland systems involves the conversion of uplands into wetlands. The wetland creation plan must be designed by a qualified wetland consultant to ensure a reasonable chance of success. Detail what is allowed and not allowed

32 Code and Ordinance Example from Town of Surfside Beach, SC Specify Use and Allow LID General Permit for Residential Construction Stormwater controls and measures guidelines. (1)Option A Infiltration; purpose. Infiltration systems are used primarily as water quality management practices. Stored runoff gradually infiltrates into the surrounding soil. The surface of the system can be covered with grating and/or consist of stone, gabion, sand or a grassed area with a surface inlet. Utilizing underground pipes within the trench can increase the temporary storage capacity of the system and can sometimes provide storage for flooding control. Allows LID

33 Code and Ordinance Example from Town of Surfside Beach, SC Specify Use and Allow LID General Permit for Residential Construction Stormwater controls and measures guidelines. (2)Option B Biofiltration swale; purpose. The purpose of a biofiltration swale is to convey stormwater runoff at a nonerosive velocity in order to enhance its water quality through infiltration, sedimentation and filtration. Check dams are used within the swale to slow the rate and create small, temporary retention areas. a. A biofiltration swale is a broad and shallow earthen channel vegetated with erosion-resistant and flood-tolerant grasses. Check dams are strategically placed in the swale to encourage retention behind them. The swale must be underlain by an appropriate or engineered soil to provide for infiltration. b. Grassed swales engineered for enhancing water quality control cannot convey large flows. The contributing drainage areas must be kept small. Grassed swales are generally suited to densities of development (sixteen (16) percent to thirtyseven (37) percent impervious). c. Soils should have moderate to high infiltration rates of twenty-seven hundredths (0.27) inches per hour or greater. d. Depth to water table should be at least three (3) feet. Wow!

34 Code and Ordinance Example from Hilton Head, SC Use Native Plants Chapter 6 Natural Resource Protection: Sec Revegetation Revegetation shall be accomplished in accordance with the following standards: A. All plants must be native plants. Refer to U.S. Fish and Wildlife Service, 1988, National List of Plant Species that Occur in Wetlands: 1988 National Summary, Biological Reports 88(24): 244pp. B. Re-vegetated areas shall be protected from vehicular encroachment C. Trees and plants required herein shall be inspected periodically after installation to determine whether they are surviving in a healthy condition. If the trees or plants appear unable to promote healthy future growth, they shall be replaced by other native plants. D. The size and species of vegetation shall be appropriate to the location being re-vegetated and the type of habitat being created, and shall be of the same species and diversity as that being removed. E. All re-vegetation shall be done in accordance with best management practices. F. No Certificate of Compliance shall be issued unless the re-vegetation meets the requirements herein provided.

35 Code and Ordinance Example from Beaufort County, SC Volume Based Stormwater Criteria Used P target by limited IC: 10% equivalent IC target Stormwater utility formed Volume based storms controlled (1.95 inches) Updated BMP Manual includes volume controls LID BMP designs provided EIC credits for combined practices Compliance worksheet for calculations Design community helped cost program Thinking ahead Water reuse for irrigation Cisterns for cooling systems County land demos Stormwater Code: Worksheet:

36 Code and Ordinance Example from Beaufort County, SC Buffers, Wetland Protection, Prohibits Beach Outfalls River Buffer: 50 foot minimum setback Detention and retention ponds shall be designed with relatively flat side slopes along the shoreline, and with meandering shorelines where possible to increase the length of shoreline, thus offering more space for the growth of littoral vegetation for pollution control purposes. Freshwater Wetlands: Vegetative strips shall be retained or created along the banks or edges of all freshwater wetlands as part of the required setback distance. The following minimum setbacks shall be established (unless already established by OCRM Charleston, S.C. District, whichever is greater) for construction from the edge of all wetlands: a. Single-family residential: 20 feet. b. Multifamily residential: 50 feet. c. Commercial or industrial: 50 feet. d. Impervious parking areas: 30 feet. Beach Outfalls: No new stormwater discharge shall be permitted onto any beaches/shorelines.

37 Code and Ordinance Examples from Coastal SC Buffers Charleston County has landscaping buffers are described (9.5.4) and land use required buffers are determined by guidelines in B (a-d). Charleston County requires wetland, waterways, and SCDHEC-OCRM critical line buffers that are 15 or 35 ft. as described in B1 (Charleston County Zoning and Land Development Regulations Ordinance, 2008). Town of Hilton Head s Land Management Ordinance provides guidance for general buffers and requires 20 to 30 ft. buffers as stated by the code and based on proposed and adjacent land use (Town of Hilton Head Island, South Carolina s Land Management Ordinance, 2007).

38 Code and Ordinance Examples from Coastal SC Buffers Town of Mount Pleasant requires critical line buffers of 15 ft. between the Cooper River Bridge and the Ben Sawyer Bridge and > 20 ft. buffer from the Cooper River Bridge east to the Wando River as well as from the Ben Sawyer Bridge north along the Intercoastal Waterway (ICWW). For new developments in the critical area, forested vegetative buffers are required for single family residence (25 ft.), for multifamily residential (50 ft.) and for nonresidential (75 ft.) based on land use and (Mount Pleasant Code of Ordinances, 2008). The Town s ordinance requires Land Use Buffers and Riparian Buffers that range from 0 to 80 ft. The buffer width is defined as a percentage of the required setbacks based on land use (Section 4.15) and measured from property line to proposed use. If a natural buffer does not exist, the Developer is required to plant a buffer with vegetation that is approved by the Town (Town of Bluffton Development Standards Ordinance, Article IV Section 4.17 Buffers, 2005).

39 Stormwater Pond on Folly Rd, Charleston, SC Chl a = 122 µg L -1

40 Discussion What are your experiences with updating codes and ordinances to allow LID, BSD, or other conservation elements? What do you need?

41 Lessons Learned Political climate should be right Must have a Local Advocate to help drive the process & implementation Give people many opportunities for Input/Output Understand limitations of the process Neutral party should facilitate process Use local examples

42 Thank you! Questions.. Sadie Drescher Charleston, SC Wadmalaw Island