Buffers and Special Water Quality Protections
Carrie J. Evenson, Ph.D.Environmental Programs Specialist IV
Industrial Wastewater Enforcement Section
Water Quality DivisionDepartment of Environmental Quality
Jason R. Vogel, Ph.D., P.E.Assistant Professor
Extension Stormwater SpecialistBiosystems and Agricultural Engr.
Oklahoma State University
Special Water Quality Protections Outstanding Resource Waters (ORWs) Aquatic Resources of Concern (ARCs) Endangered/Threatened Species Impaired Waters
Buffer Requirements
Outline
Special Water Quality Protections
Outstanding Resource Waters (ORWs) Waters of the State designated in Oklahoma’s
Water Quality Standards, OAC 785:45, Appendix A
Include Illinois River & Lee Creek watersheds and Mountain Fork River watershed
Addendum F of OKR10 indicates locations
Outstanding Resource Water/Aquatic Resource of
Concern
Aquatic Resources of Concern (ARCs) Includes sections of the following:
Outstanding Resource Water/Aquatic Resource of
Concern
Grand (Neosho) River
Cimarron River South Canadian
River Muddy Boggy River Kiamichi River Little River
Glover River Mountain Fork River Spring River Illinois River Lee and Little Lee
Creeks Certain watersheds
Aquatic Resources of Concern (ARCs) Counties with no stormwater discharge-sensitive
endangered/threatened species:
Outstanding Resource Water/Aquatic Resource of
Concern
Alfalfa Beckham Carter Cimarron Comanche Garfield
Garvin Grant Greer Johnston Kiowa Lincoln
Murray Nowata Okfuskee Oklahoma Okmulgee Rogers
Stevens Texas Washita Washington
For sites discharging to ORW/ARC Indicate on NOI and address in SWP3
Inspection requirements Minimum of once every 7 days and within 24 hours of
a storm event of ≥0.5 inches or within 24 hours of snowmelt-related discharge
Outstanding Resource Water/Aquatic Resource of
Concern
For sites discharging to ORW/ARC Stabilization requirements
Initiated immediately following day earth-disturbing activities have temporarily or permanently ceased
Completed within 7 days
Corrective actions required
Outstanding Resource Water/Aquatic Resource of
Concern
For sites discharging to ORW/ARC 100 ft buffer zone required
Alternately, use Addendum I “Buffer Guidance” for equivalent controls
Temporary or permanent sediment basin required for areas that serve an area with ≥5 acres disturbed
Outstanding Resource Water/Aquatic Resource of
Concern
For sites discharging to ARC Discharge must be protective of listed
endangered/threatened species or designated critical habitat
Applicant must comply with requirements, conditions, terms identified as necessary to meet eligibility requirements
Outstanding Resource Water/Aquatic Resource of
Concern
Important Note:
Permit does not authorize discharges that cause a prohibited “take” or that are likely to jeopardize continued existence of species or habitat
Endangered/Threatened Species
Procedure for assessing potential effects of discharge on listed species (see Part 11): Complete prior to submitting NOI Step 1: Determine if project discharges to ARC
If project doesn’t discharge to ARC, no additional steps are necessary.
If project does discharge to ARC, proceed to Step 2.
Endangered/Threatened Species
Procedure for assessing potential effects of discharge on listed species (see Part 11): Step 2: Implement stormwater control
measures to protect listed species Retain sediment on site to the greatest extent
practicable Establish/retain 100 ft buffer zone or equivalent Follow stabilization requirements
Endangered/Threatened Species
Applicant must certify that it meets at least ONE of following criteria: Site is not located within any of the Aquatic
Resource of Concern (ARC) corridors; OR Site is located within ARC corridor and SWP3
describes area and measures used to protect species or habitat; OR
Endangered/Threatened Species
Applicant must certify that it meets at least ONE of following criteria (cont’d): Site is federally approved/authorized and
addresses Endangered Species act Section 7 consultation Must include documentation demonstrating
Section 7 consultation; OR Applicant’s discharge(s) is/are addressed in
another operator’s certification of eligibility
Endangered/Threatened Species
Applicant must certify that it meets at least ONE of following criteria (cont’d): If one of above can’t be met, may use Buffer
Guidance to select equivalent sediment controls or contact DEQ for guidance No longer necessary to contact USFWS for
guidance on alternatives
Endangered/Threatened Species
Identified by State or EPA pursuant to Section 303(d) of the Clean Water Act as not meeting applicable State water quality standards Includes
Waters with approved or established TMDLs, and Waters for which a TMDL has not yet been
established or approved
Impaired Waters
303(d) list and approved TMDLs/watershed plans can be found on DEQ website: For 303(d) list:
http://www.deq.state.ok.us/wqdnew/305b_303d/index.html
For approved TMDLs/watershed plans:http://www.deq.state.ok.us/wqdnew/tmdl/index.html
Impaired Waters
For sites discharging pollutants of concern to receiving water on 303(d) list: Document how BMPs will control discharge of
pollutants of concern If TMDL or watershed plan has been
approved Describe how SWP3 is consistent with
TMDL/watershed plan
Impaired Waters
For sites within one mile of streams impaired for sediment: Indicate on Notice of Intent Inspection requirements
Minimum of once every 7 days and within 24 hours of a storm event of ≥0.5 inches or within 24 hours of snowmelt-related discharge
Impaired Waters
For sites within one mile of streams impaired for sediment: Corrective actions
Document within 24 hours and implement within 7 days of discovery
Stabilization requirements Initiated immediately following day earth-
disturbing activities have temporarily or permanently ceased
Completed within 7 days
Impaired Waters
Buffer Requirements
Two (2) buffer requirements (see Addendum I) Alternative 1:
For sites discharging into receiving water located on or immediately adjacent to your site that are not an ARC or ORW Provide 50 feet of natural buffer as measured
from the top of the bank to disturbed portions of the site
Buffer Requirements
Two (2) buffer requirements (see Addendum I) Alternative 2:
For sites discharging to the watershed of ARC and/or ORW Provide 100 feet of vegetated buffer between
area disturbed and all perennial or intermittent streams; or 50 feet of vegetated buffer between area disturbed and all ephemeral streams or drainages.
Buffer Requirements
Retain and protect as much natural buffer from construction activities as possible Preexisting structures and impervious surfaces
are allowed in buffer provided vegetation outside preexisting disturbance is maintained
Buffer Requirements
Do not conduct earth-disturbing activities within buffer during permit coverage
Ensure all discharges are first treated by erosion and sediment controls before entering buffer
Buffer Requirements
Natural buffers and equivalent sediment controls don’t apply when: Water crossings, limited water access, and
stream restoration authorized under a Clean Water Act (CWA) Section 404 permit exist
No natural buffer exists due to preexisting development disturbances (e.g., structures, impervious surfaces)
Buffer Requirements
Three compliance alternatives Alternative 1: Provide and maintain a 50/100-
foot undisturbed natural buffer Alternative 2: Provide and maintain <50/100-
foot buffer and install additional erosion and sediment controls
Alternative 3: Implement equivalent erosion and sediment controls to achieve the same sediment load reduction as provided by a 50/100 foot natural buffer if natural buffer of any size is infeasible
Buffer Requirements
Buffer Requirements
Using Addendum I Step 1: Determine if buffer is required Step 2: Determine which compliance
alternative to use Step 3: If Alternative 1, measure existing
buffer width and retain and protect required natural buffer width Measured perpendicularly from the ordinary high
water mark or the edge of the stream or river bank, bluff or cliff For meandering waterbodies, you may measure in
regular intervals instead of measuring each change
Buffer Requirements
Step 4: If Alternative 2 or 3 selected: Document width and location of buffer in SWP3
(Alt. 2) Document why it is infeasible to provide and
maintain an undisturbed natural buffer of any size in the SWP3
Determine what additional controls must be implemented along with any retained natural buffer Addendum I lists process for determining which
BMP or combination of BMPs can provide equivalent sediment reduction as natural buffer
Determining equivalent sediment reduction Step 1: Estimate removal efficiency at site if
50/100 ft buffer could be provided Equivalent erosion and sediment controls must
provide sediment load reduction equivalent to this
Dependent on site-specific factors Includes precipitation, soil type, land cover, slope
length, width, steepness, and types of sediment controls used to reduce the discharge of sediment prior to the buffer
Buffer Requirements
Estimating removal efficiency of buffer Use buffer performance standards included in
Appendix I, Tables I-1 through I-4OR Conduct a site-specific calculation for sediment
removal efficiency Provide the specific removal efficiency and the
information used for the site-specific calculation in your SWP3
Buffer Requirements
Things to note when using Tables I-1 through I-4: Developed by Dr. Jason Vogel and Katie Beitz,
Biosystems and Agricultural Engineering, Oklahoma State University
Choose vegetation type that most closely matches vegetation that would exist naturally, regardless of condition No supplemental planting required Take credit as a fully vegetated “natural buffer” in
subsequent calculations
Buffer Requirements
Example: I am developing a commercial site in
Oklahoma City. How do I know if I need to have a buffer?
1. Take a look at how close the site is to the nearest surface water
Buffer Requirements
I’ve looked at my site, and it looks like I will need to clear ground within 50 feet of the stream in order to build my parking lot. Now what? Earth-disturbing activities will occur within 50
feet of surface water: Buffer is required Is surface water an ORW or ARC?
If NO – 50 ft buffer required If YES – 100 ft buffer required
Buffer Requirements
So I know I need to provide a 50 ft buffer. What’s next?1. Determine if you can provide the entire 50 feet
of undisturbed buffer on your site. If YES – protect buffer from earth-disturbing
activities for the duration of the project If NO – determine how much of a buffer can be
provided and what equivalent sediment control measures you will install instead Use Tables I-1 through I-4 for this
Buffer Requirements
I can’t maintain any buffer at my site. Now what do I do? Use Appendix I, Tables I-1 through I-4 to
determine sediment reduction provided by 50 feet of undisturbed natural buffer Site location: Oklahoma City Natural buffer vegetation: Weeds Site condition: Blade fill Soil type: Sand
Buffer Requirements
Example using Appendix I, Tables I-1 through I-4: Site location: Oklahoma City Natural buffer vegetation: Weeds Site condition: Blade fill Soil type: Sand Sediment removal efficiency based on Table I-
1: 41%
Buffer Requirements
I found the removal efficiency of a natural buffer at my site. How do I determine what sediment controls can provide an equivalent sediment load reduction? Select stormwater control(s) you want to use and
Use Table I-1 through I-4 to determine sediment load reduction OR
Use a model or other type of calculator showing how BMPs meet or exceed the sediment removal efficiency from Step 1
Buffer Requirements
If using Appendix I, Tables I-1 through I-4: Site location: Oklahoma City Natural buffer vegetation: Weeds Site condition: Blade fill Soil type: Sand Sediment removal efficiency of buffer based on
Table I-1: 41% Proposed sediment control measure: 12”
waddle
Buffer Requirements
Using Appendix I, Tables I-1 through I-4: Site location: Oklahoma City Natural buffer vegetation: Weeds Site condition: Blade fill Soil type: Sand Sediment removal efficiency of buffer based on
Table I-1: 41% Proposed sediment control measure: 12” waddle Equivalent sediment reduction of control measure:
90%
Buffer Requirements
Buffer Requirements
My selected sediment control provides adequate sediment load efficiency. Am I done yet? Document information from previous steps in SWP3
including: Buffer vegetation and soil type if Tables I-1 through I-4
are usedOR
Specific removal efficiency and other information for site-specific calculation
Stormwater control(s), model or calculator used (other than Tables), and results of calculations
So what if I don’t want to use Tables I-1 through I-4? Use other available calculation methods or
models
Buffer Requirements
Alternative Calculation Methods
Alternative Calculation Methods
Model options for calculating effectiveness of alternative controls RUSLE-series programs (USDA) WEPP (USDA) SEDIMOT series (downloadable, developed by
Barfield et al.) SedPro (Woolpert, Inc.) SEDCAD (Civil Software Design, LLC)
RUSLE – Revised Universal Soil Loss Equation
A = (R)(K)(LS)(C)(P)
A=Erosion per unit areaK=Soil Erodibility
LS=Land slope and lengthC=degree of soil coverSupporting practices
Erosivity - R
Las Vegas, NV 8Phoenix, AZ 22Denver, CO 40Syracuse, NY 80Minneapolis, MN 110Chicago, IL 140
Measure of erosivity of climate at a location
Richmond, VA 200St. Louis, MO 210Tulsa, OK 260Dallas, TX 275Birmingham, AL 350Charleston, SC 400New Orleans, LA 700
SOIL ERODIBILITY - K
Effect of texture clay (0.1 - 0.2) resistant to detachment sand (0.05 - 0.15) easily detached, low
runoff, large, dense particles not easily transported
silt loam (0.25 - 0.35) moderately detachable, moderate to high runoff
silt (0.4 -0.6) easily detached, high runoff, small, easily transported sediment
LS Factor – Length Slope
Describes Topography Overland flow slope length Slope lengths for eroding portions of
hillslopes Steepness Hillslope shape
Slope Length for Eroding Portion of Slope
Only works for simple slopes Traditional definition
Distance from origin of overland flow to concentrated flow or to where deposition begins
Definition is flawed for strips and concave:convex slopes
Best approach: Use overland flow slope length and examine RUSLE2 slope segment soil loss values
Detachment Proportional to Slope Steepness Factor (S)
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0 5 10 15 20 25 30 35
Slope Steepness (%)
Fa
cto
r V
alu
eNot affected by any other variable
C & P Factors – Based on Land Use
C: Cover-management
P: Supporting practices
Cover-Management
Vegetative community Crop Crop rotation Conservation tillage Application of surface and buried materials
(mulch, manure) Increasing random roughness
Supporting Practices
Erosion control (called permeable barriers) Silt fence, waddles, check dams
Contouring Strip systems
Buffer, filter, strip cropping, barriers Terrace/Diversion Impoundments
Example
Changing the Average
Steepness and Length of Slope
Choosing the Location
Example: Tulsa, OK
Choosing the Soil of the Site
Example: Silt Loam
Choosing the Management of
the Surface
Example: the first 50 feet are
blade cut
Choosing the Management of
the Surface
Example: we added a silt fence at 50
feet, and added a barrier strip for the second 50’ of the area
Adding a Wattle
Example: 6” Wattle
In this screen you can also set
the spacing, and number of wattles used
Estimate Sediment Removal
Soil Loss - Sediment DeliverySoil Loss
Example: 39-2.5/39 = 94%
Questions, Comments, Discussion
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