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APA Florida 2011 Conference
by Robert W. Higgins, P.E.
FDEP Unified Stormwater RuleVs.
EPA Numeric Nutrient Criteria
West Palm Beach, Florida
September 9, 2011
Question:How does the EPA Numeric Nutrient Criteria fit with the Unified Stormwater Rule proposed by Florida Department of Environmental Protection
?
Answer:• It is unknown at this time
• There is a considerable amount of confusion
• EPA NNC Applies to All Discharges• FDEP Stormwater Rule Applies to New Discharges
BACKGOUND:Issue First Raised in Southwest FloridaState 401 Water Quality Certification
Rejected by EPAHarver Harper Methodology Used to
Demonstrate “Pre vs Post” Water Quality Loading is Met
SFWMD Proposes a Special Basin Rule for SW Florida
FES (and others) Requests Looking at Statewide Applicability
STATEWIDE RULE STATUS2008 – 2009: Technical Advisory Comm.May 2010: Conducted Public WorkshopsSeptember 2010: Revised Draft Rule CriteriaNovember 2010: Conduct Public WorkshopsMarch 2011: Revised Draft Rule Criteria
(additional workshops TBD)May 2011: Authorizing Legislation – Not FiledJuly 2011 or Later: Rule Adoption – Not DoneNext Step – Unknown
Recent Senate Committee Report Recommends a Uniform Statewide Environmental Resource Permit
WHY NOW?
STATEWIDE STORMWATER RULE OBJECTIVES
Increase Nutrient RemovalRequirements for Discharge to Impaired
WatersStatewide ConsistencyAdditional BMPsBMP Treatment Train CreditEncourage Low Impact DesignEncourage Redevelopment & RetrofittingRule not applicable to Agricultural Uses
STATEWIDE STORMWATER RULE
Limits average annual nutrient load for total phosphorus (TP) & total nitrogen (TN)85% treatment efficiency (load reduction) or;Post development load less than load from
natural land cover condition (Post = Pre), whichever is less stringent
Adds several new treatment methods (BMPs) with specific nutrient removal quantification
One statewide methodology that allows for differing regional conditions
BMPsPrimary Quantifiable BMPs:
Wet Detention Ponds (residence time calculation)Dry Retention Ponds (retention)Pervious Pavement Systems (retention)Stormwater Harvesting (recycling/retention)Green Roof/Cistern Systems (retention)Exfiltration trench/underground vaults (retention)Swales (retention/percolation)
BMPs
Additional BMPs Needing More Input/DataUnderdrain Filtration (dry retention with
underdrains)Dry DetentionWetland TreatmentVegetated BuffersManaged Aquatic Plant SystemsLow Impact Design BMPs
REDEVELOPMENT & RETROFITS
Currently, redevelopment that demolishes to bare earth will require full treatmentHowever, redevelopment less than a specific
acreage may provide a feasibility analysis to demonstrate that a lower level is appropriate (provide as much treatment as site can provide)
Minor Retrofit Projects Require Net Improvement
STAY UP TO DATE
Web Site:www.dep.state.fl.us/water/wetlands/erp/rules/stormwater/index.htmSign Up for Email List on Web Site
PROBLEMS“Pre” is Considered to be “Pre Man”Wetlands Are Considered NeutralLimited DataDoes One Size Fit All? (Five WMD’s For a
Reason)Unknown Benefits For Certain BMP’sAgriculture is ExemptLarge Economic Impact (More Land Area
Required)Criteria is Still PresumptiveCompliance With NNC UnknownLengthy Rulemaking – Likely Challenged
APA Florida 2011 Conference
FDEP Unified Stormwater Rulevs.
EPA Numeric Nutrient CriteriaQUESTIONS
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