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IT’S TIME TO GET YOUR MIND IN THE GUTTER! Overview of Proposed Coastal Stormwater Rules February 14, 2008.

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Presentation on theme: "IT’S TIME TO GET YOUR MIND IN THE GUTTER! Overview of Proposed Coastal Stormwater Rules February 14, 2008."— Presentation transcript:

1 IT’S TIME TO GET YOUR MIND IN THE GUTTER! Overview of Proposed Coastal Stormwater Rules February 14, 2008

2 Rules Affect ALL Land in Twenty Coastal Counties With Disturbance Greater Than 10,000 Sq. Ft. Beaufort, Bertie, Camden, Carteret, Chowan, Craven, Currituck, Dare, Gates, Hertford, Hyde, Pamlico, Pasquotank, Pender, Perquimans, Tyrrell, Washington AND Phase II Counties - Brunswick, New Hanover and Onslow.

3 Understanding the Rules: Definition of Terms Land Disturbing Activity Land Disturbing Activity Built-Upon Area Built-Upon Area Lot Coverage Lot Coverage Vegetative Buffer Vegetative Buffer SA Waters SA Waters

4 Land Disturbing Activity DWQ Definition: Any use of the land that results in a change in the natural cover or topography that may cause or contribute to sedimentation.

5 Built-Upon Area (BUA) That portion of a project that is covered by impervious or partially impervious surface including, but not limited to, buildings; pavement and gravel areas such as roads, parking lots, and paths; and recreation facilities such as tennis courts. Does not include a wooden slatted deck, the water area of a swimming pool, or pervious or partially pervious paving material to the extent that the paving material absorbs water or allows water to infiltrate through the paving material. Septic systems/drain fields are not impervious surfaces.

6 BUA – How is it measured? Built-upon area is a measure of the hard surfaces or impervious cover for a site. For each piece of land, divide the amount (area) of impervious surface (i.e.: structures, roads, parking lots) located on-site by the total land area under consideration. Multiply the resulting fraction by 100 to get the percent built-upon area. Built-upon area is a measure of the hard surfaces or impervious cover for a site. For each piece of land, divide the amount (area) of impervious surface (i.e.: structures, roads, parking lots) located on-site by the total land area under consideration. Multiply the resulting fraction by 100 to get the percent built-upon area. If disturbing more than one acre of land for residential development, or 10,000 sq. ft. for non-residential development, wetlands cannot be included in total land area under consideration. If disturbing more than one acre of land for residential development, or 10,000 sq. ft. for non-residential development, wetlands cannot be included in total land area under consideration.

7 Lot Coverage Defined by each municipality and County. Defined by each municipality and County. Do not confuse with Built-Upon Area. Do not confuse with Built-Upon Area. Prior built-upon area low density thresholds (25%/30%) may have been more flexible than local lot coverage allowance. Prior built-upon area low density thresholds (25%/30%) may have been more flexible than local lot coverage allowance.

8 Vegetated Buffer "Vegetative Buffer" means an area of natural or established vegetation directly adjacent to surface waters through which stormwater runoff flows in a diffuse manner to protect surface waters from degradation due to development activities. "Vegetative Buffer" means an area of natural or established vegetation directly adjacent to surface waters through which stormwater runoff flows in a diffuse manner to protect surface waters from degradation due to development activities. The width of the buffer is measured horizontally from the normal pool elevation of impounded structures, from the bank of each side of streams or rivers, and from the mean high water line of tidal waters, perpendicular to the shoreline." The width of the buffer is measured horizontally from the normal pool elevation of impounded structures, from the bank of each side of streams or rivers, and from the mean high water line of tidal waters, perpendicular to the shoreline."

9 Will I Need A Stormwater Permit? Section A Residential Residential Permitting threshold is one acre of land disturbance. If you are clearing, grading, etc. one acre or more – you will need to apply for a state stormwater permit. Non-Residential Non-Residential Permitting threshold is 10,000 sq. ft. of land disturbance Includes projects that disturb less than 10,000 sq. ft. but are part of a larger plan for development or sale.

10 SA Waters Commercial shellfishing waters. Commercial shellfishing waters. Domestic Wastewater Discharges are not allowed. Domestic Wastewater Discharges are not allowed. Provisions for stormwater controls. Provisions for stormwater controls. Class SA Waters also carry a supplemental designation of HQW (High Quality Water) or ORW (Outstanding Resource Water). Class SA Waters also carry a supplemental designation of HQW (High Quality Water) or ORW (Outstanding Resource Water).

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12 Dare County SA Waters Map documents/dare.pdf Boundaries on map include land “within ½ mile of SA waters” documents/dare.pdf documents/dare.pdf

13 No SA Waters Part of Kill Devil Hills, Kitty Hawk, Southern Shores, Duck, Currituck Outer Banks Part of Kill Devil Hills, Kitty Hawk, Southern Shores, Duck, Currituck Outer Banks Majority of downtown Manteo Majority of downtown Manteo East Lake East Lake Bertie, Camden, Chowan, Currituck, Gates, Hertford, Perquimans, Tyrell, Washington Bertie, Camden, Chowan, Currituck, Gates, Hertford, Perquimans, Tyrell, Washington

14 Residential Exclusion If your lot is part of a larger subdivision that was issued a stormwater permit, you do not need to do anything for stormwater runoff – you’re already covered under that permit!

15 I Need a Permit – Next Step: Determine Built-Upon Area As noted previously, wetlands cannot be included in the overall project area to calculate impervious surface density (BUA). As noted previously, wetlands cannot be included in the overall project area to calculate impervious surface density (BUA). –This does not mean that wetlands cannot be impacted – the BUA percentage is only used to determine whether your project needs to comply with LOW DENSITY or HIGH DENSITY stormwater requirements.

16 I Need a Permit: New Buffer Requirement A 50-foot vegetated buffer is required whether low or high density; a lawn would qualify as “vegetated” – Buffer is similar to “setback”. Buffer rules are different in the Tar-Pam and Neuse River Basins. (Increased from 30-foot) A 50-foot vegetated buffer is required whether low or high density; a lawn would qualify as “vegetated” – Buffer is similar to “setback”. Buffer rules are different in the Tar-Pam and Neuse River Basins. (Increased from 30-foot)

17 Buffer (con’t) 30-foot buffer for redevelopment 30-foot buffer for redevelopment –provided there is no net increase in impervious surfaces and the redevelopment incorporates equal or better stormwater controls that the previous development. –Provision allows for the rebuilding of homes, businesses and other structures in the event of natural disasters without mandating strict compliance with the new provisions in the rules.

18 I Need a Permit – Am I Within One- Half Mile and Draining to SA Waters SA Waters Map - DWQ SA Waters Map - DWQ Land Quality Map Land Quality Map Streams or Tributaries on Property Streams or Tributaries on Property –If rated as a stream or tributary but not appearing on a map – requirements will still need to be met and the “within ½ mile” rule would include areas adjacent to the stream or tributary. (Make sure a ditch is a ditch!)

19 Yes – I’m Within One-Half Mile … What is the BUA? Low Density – 12% or Less BUA Low Density – 12% or Less BUA –Runoff transported by vegetated conveyances OR High Density – Over 12% BUA High Density – Over 12% BUA –Control systems must be infiltrations systems, wet detention ponds, bioretention systems, constructed wetlands, sand filters or ALTERNATIVE STORMWATER MANAGEMENT SYSTEM.

20 High Density (con’t) Systems will need to control and treat runoff from all impervious surfaces by one and one-half inches or rainfall or the DIFFERENCE in the runoff from pre and post-development conditions for the one-year 24-hour storm – whichever is greater. (In Dare County, the one- year 24-hour storm condition is approx. 3 ½ inches of rain) Systems will need to control and treat runoff from all impervious surfaces by one and one-half inches or rainfall or the DIFFERENCE in the runoff from pre and post-development conditions for the one-year 24-hour storm – whichever is greater. (In Dare County, the one- year 24-hour storm condition is approx. 3 ½ inches of rain) If INFILTRATION meets the requirements under the rules then it will be acceptable as an alternative system. If INFILTRATION meets the requirements under the rules then it will be acceptable as an alternative system.

21 All Permits - Low and High Density Requirements Prohibit new points of stormwater discharge Prohibit new points of stormwater discharge No expansion of existing conveyance systems draining to SA waters No expansion of existing conveyance systems draining to SA waters No increase in net amount or rate of discharge through existing outfalls No increase in net amount or rate of discharge through existing outfalls Infiltration of the one-year 24-hour storm? Intent is “No NEW runoff from the 1-yr 24-hour storm. (Confusing and needs clarification) Infiltration of the one-year 24-hour storm? Intent is “No NEW runoff from the 1-yr 24-hour storm. (Confusing and needs clarification)

22 I Need a Permit but I’m Outside of One-Half Mile SA …., ETC. Low Density – 24% or Less BUA Low Density – 24% or Less BUA –Runoff transported by Vegetated Conveyance OR High Density – Over 24% BUA High Density – Over 24% BUA –Control systems must be infiltrations systems, wet detention ponds, bioretention systems, constructed wetlands, sand filters or ALTERNATIVE STORMWATER MANAGEMENT SYSTEM. –Must be designed to STORE, control and TREAT runoff generated by one and one-half inch or rainfall.

23 Requirements of Structural Controls Same as Phase II Same as Phase II –Remove an 85% average annual amount of Total Suspended Solids –For detention ponds – draw down the treatment volume no faster than 48 hours, but no slower than 120 hours. –Discharge volume at a rate = or less than pre-development for 1-year, 24-hour storm. –Meet General Engineering Design Criteria.

24 Structural Controls and High-Water Table Separation For controls that require separation from seasonal high-water table, a minimum of two feet is mandated. For controls that require separation from seasonal high-water table, a minimum of two feet is mandated. Need 12 inches of naturally occurring soil above the seasonal high water table with a minimum soil hydraulic conductivity of 0.52 inches per hour. Need 12 inches of naturally occurring soil above the seasonal high water table with a minimum soil hydraulic conductivity of 0.52 inches per hour.

25 Summary – Permitting Requirements – Sec. A If disturbing more than one acre residential or 10,000 sq.ft. non-residential If disturbing more than one acre residential or 10,000 sq.ft. non-residential –Stormwater permit required and –50-ft. vegetated buffer for new development; 30 ft. for redevelopment Definition of vegetated buffer different in Neuse and Tar- Pam River Basins (can be disturbed; buffer can be a lawn in Dare County) and Definition of vegetated buffer different in Neuse and Tar- Pam River Basins (can be disturbed; buffer can be a lawn in Dare County) and –No credit for wetlands in computing built-upon area.

26 Summary (con’t) - Permitting Requirements If < ½ mile from and draining to SA waters If < ½ mile from and draining to SA waters –No new points of discharge; no increase in flow to SA waters. –Level spreaders to diffuse any flow through wetland areas –12% or less built-upon area = low density No engineered stormwater controls required on site No engineered stormwater controls required on site Stormwater must be primarily conveyed by vegetated conveyances Stormwater must be primarily conveyed by vegetated conveyances –Greater than 12% built-upon area = high density Structural stormwater controls required or any BMP Structural stormwater controls required or any BMP For structural controls, minimum separation of 12” of natural soil above seasonal high water table For structural controls, minimum separation of 12” of natural soil above seasonal high water table Need to control and treat the difference in runoff from pre- development/post-development one-year 24-hour storm conditions within property boundary. Need to control and treat the difference in runoff from pre- development/post-development one-year 24-hour storm conditions within property boundary.

27 Summary (con’t) - Permitting Requirements If > ½ mile from and draining to SA waters If > ½ mile from and draining to SA waters –24% or less built-upon area = low density Stormwater conveyed primarily by vegetated conveyances Stormwater conveyed primarily by vegetated conveyances –> 24% built-upon area = high density Structural engineered controls required or any BMP Structural engineered controls required or any BMP Will need to store, control and treat runoff from one and one-half inch of rainfall. Will need to store, control and treat runoff from one and one-half inch of rainfall.

28 No Stormwater Permit Needed – But Part of the Rules! Sections B and C New residential development with land disturbance over 10,000 sq. ft. but less than an acre AND BUA is greater than 12% within ½ mile and draining to SA waters New residential development with land disturbance over 10,000 sq. ft. but less than an acre AND BUA is greater than 12% within ½ mile and draining to SA watersOR New residential development with land disturbance over 10,000 sq. ft. AND BUA is greater than 24% outside of ½ mile SA waters. If lot is part of a larger subdivision that was already issued a stormwater permit, then you should not have to comply with these rules. (This is not clearly stated in Sections B and C and needs to be clarified!)

29 Within ½ mile…. Collect all rooftop runoff from one-year 24-hour storm in rain barrels or cisterns. All uncovered areas to be paved need to be constructed of permeable pavement or other pervious material OR Collect all rooftop runoff from one-year 24-hour storm in rain barrels or cisterns. All uncovered areas to be paved need to be constructed of permeable pavement or other pervious material OR Direct all rooftop runoff from one-year 24-hour storm to a rain garden. All uncovered areas to be paved need to be constructed of permeable pavement or other pervious material OR Direct all rooftop runoff from one-year 24-hour storm to a rain garden. All uncovered areas to be paved need to be constructed of permeable pavement or other pervious material OR Install any other BMP to control and treat the difference in runoff from pre-development/post development one- year/24-hour storm conditions. Install any other BMP to control and treat the difference in runoff from pre-development/post development one- year/24-hour storm conditions.

30 Outside of ½ mile, ETC. Collect all rooftop runoff from the first 1.5 inches of rainfall in rain barrels or cisterns. All uncovered areas to be paved need to be constructed of permeable pavement or other pervious material OR Collect all rooftop runoff from the first 1.5 inches of rainfall in rain barrels or cisterns. All uncovered areas to be paved need to be constructed of permeable pavement or other pervious material OR Direct all rooftop runoff from the first 1.5 inches of rainfall to a rain garden. All uncovered areas to be paved need to be constructed of permeable pavement or other pervious material OR Direct all rooftop runoff from the first 1.5 inches of rainfall to a rain garden. All uncovered areas to be paved need to be constructed of permeable pavement or other pervious material OR Install any other BMP to control and treat the runoff the first 1.5 inches of rainfall. Install any other BMP to control and treat the runoff the first 1.5 inches of rainfall.

31 CHALLENGES OF RULES Intent/Purpose Intent/Purpose DWQ has no statute authority to mandate that local governments enforce or monitor sections B and C. DWQ has no statute authority to mandate that local governments enforce or monitor sections B and C. Sections B and C will be self-regulating and compliance will be complaint-driven. Sections B and C will be self-regulating and compliance will be complaint-driven. Sections B and C do not specifically exclude lots in subdivisions already under a stormwater permit Sections B and C do not specifically exclude lots in subdivisions already under a stormwater permit As written, under Section A-2-C combined with A-2-B – lots may be unbuildable. As written, under Section A-2-C combined with A-2-B – lots may be unbuildable. Official Maps? Official Maps? Interpretation by local officers? Interpretation by local officers? Incorporating local rules Incorporating local rules Vested Rights? Vested Rights? COST $$$$ COST $$$$

32 What’s Next? Rules go before Rules Review Commission Feb 21 st. Rules go before Rules Review Commission Feb 21 st. If sent for Legislative Review If sent for Legislative Review –Changes and clarifications may be made. –If no action taken by Committee, rules as presented become effective August 1, Local Cooperation/Control Local Cooperation/Control –Lot coverage definition – Can we come up with ONE county-wide definition? –Setback Requirements? –County-wide USMP?

33 Universal Stormwater Management Plan (USMP) Local control of stormwater rules Local control of stormwater rules Supersedes Coastal Stormwater Rules Supersedes Coastal Stormwater Rules Permitting threshold would be 10,000 Sq. Ft. of land disturbance Permitting threshold would be 10,000 Sq. Ft. of land disturbance Plan would have to meet minimum requirements approved by DWQ Plan would have to meet minimum requirements approved by DWQ Permit issued locally – municipality or County Permit issued locally – municipality or County Rule language: USMP-FinalEffectiveRule_.pdf Rule language: USMP-FinalEffectiveRule_.pdf More info: More info:

34 Additional info: Division of Water Quality – Tom Reeder Environmental Supervisor x 528 FAX: Website on Stormwater Rules:

35 Questions? Willo Kelly – Government Affairs Director Outer Banks Home Builders Association Outer Banks Realtors Association


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