update to delaware sediment & stormwater regulations

C T A C M E E T I N G

N O V E M B E R 8 , 2 0 1 7

Update to Delaware Sediment & Stormwater Regulations

Randy Greer, PEDNREC Sediment & Stormwater Program

Sediment & Stormwater Program

Employs a comprehensive approach to sediment control (both during and after construction) and stormwatermanagement that includes monitoring of stormwaterquantity and water quality control. Program responsibilities include:

Sediment control and inspection during construction

Post-construction inspection of permanent stormwaterfacilities

Stormwater quantity and water quality control

Education/training relating to stormwater


Original Sediment and Stormwater Regulations adopted in 1990

In response to Executive Order 62 signed into effect by Gov. Minor, a Task Force on Surface Water Management was established and findings published in 2005

As a result, regulations were developed and issued in 2013 with a final adoption in 2014

Guiding Principals that changed 1990 vs 2013/14: Peak-based to Volume-based management

Site-level to Watershed-level management

Separated regulatory language from technical requirements

Streamlined plan review/approval process


Regulations = WHAT Regulatory Authority

Applicability

Compliance Details

Technical Document = HOW Information that supports regulations

Background information

Procedures

Checklists

Standards & Specifications

Examples

Sediment & Stormwater Regulation Revisions

Where are we now?

October 2015 – Delaware Superior Court invalidated the 2013/2014 version of the Delaware Sediment and Stormwater Regulations on procedural grounds

April 2016 – Delaware Supreme Court upheld the Superior Court’s decision

April 2016 – DNREC adopts interim emergency sediment and stormwater regulations

June 2016 – Gov. Markel signs SB 253 into law authorizing DNREC to provide additional flexibility in meeting standards for sediment and stormwaterregulations


Senate Bill 253 – Changes to the Law:

E&S only for residential land disturbing activity less than one acre.

Ag Structures (including poultry houses) disturbing 10 acres or less qualify for Standard Plans.

Stormwater discharges for the 10-YR and 100-YR storm events not required to manage runoff volume.

Allows alternative method to calculate the RPv volume based on 1” of runoff.

Allows applicants to use the provisions under SB 253 or continue under the 2016 Emergency Regulations.

Allows applicants to use additional BMPs that are functionally equivalent.

Extends the approval period for plans from 3 years to 5 years.

Extends the re-delegation period from 3 years to 5 years.

This compromise allows additional time for the RAC to thoroughly discuss all of the necessary amendments to the Sediment and Stormwater Regulations by eliminating the 180 day expiration of the Emergency Regulations.


Regulatory Advisory Committee – RAC

Name AffiliationAdams, Chuck Delaware Assn of SurveyorsBross, Jeff Water Infrastructure Advisory CouncilCasey, John Delaware Contractors' AssnClark, Jeff Board of Landscape ArchitectureDurstein, Dirk Dept. of JusticeGilliam, LaTonya DelDOTHokuf, Doug New Castle CountyHolland, Connie Office of State Planning CoordinationHorsey, Bobby David G. Horsey & SonsJones, Bruce ACEC ‐ DEKea, Frank Secretary Designee ‐ Land Development ConsultantKeifer, Sarah Kent CountyKillmer, Lew League of Local GovernmentsMcGinnis, Phil Delaware Association of RealtorsMedlarz, Hans Sussex CountyMorrill, Paul Committee of 100Palmer, Bob DNREC Secretary's OfficeRiemann, Michael Homebuilders Assn of DelawareSchell, Preston Secretary Designee ‐ Land DeveloperTravers, Kristen Delaware Nature SocietyWatson, Jessica Delaware Assn of Conservation Districts


What’s Next?

Technical Subcommittee Meetings are scheduled to tackle the details: Standards Plans – 1 Acre Lots and Ag (Poultry) Operation

New RPv Volume – 1” of runoff

Regulations

Technical Standards

Offsets

Redevelopment


What are the Source Water Protection Issues Related to Urban Stormwater Runoff?


EPA NURP (c. 1970s)

First EPA funded research on water quality of stormwater runoff

28 metropolitan locations

Metals and nutrients major threats

Generally focused on surface water impacts

Two project sites located over sole source aquifers did not appear imminently threatened, but more research recommended


National StormwaterBMP Database (2001)

International Stormwater Quality Database (since 2004)

Over 600 BMP studies All 50 states + 4

countries Consistent with NURP

results, except for Pb Also focused on surface

water impacts (influent vs. effluent)


Drinking Water Stds

(MCLs)

Cu: 1.3 mg/L (P)

Pb: 0.015 mg/L (P)

Zn: 5 mg/L (S)

NO2: 1 mg/L (P)

NO3: 10 mg/L (P)

Constituents listed in National Drinking Water Regulations


What are the Source Water Protection Issues?

Potential GW contaminants in stormwater runoff Nutrients

Metals

Chlorides?

National Secondary Drinking Water Regulations: 250 mg/L


What are some best practices for managing chloride deicers?

Covered storage

Calibrated application equipment

Pre-treatment

Alternative deicing compounds Beet juice derivatives

Calcium magnesium acetate (CMA)


What other measures do the DSSR contain to protect Source Water?


What measures do the DSSR contain to protect Source Water?

Pretreatment required for all infiltrating practices Vegetative filtration

Forebays

Pre-engineered practices

Vertical separation from SHGW Minimum 2’

Horizontal setback distances between wells and stormwater BMPs


GW Discharge BMPs Surface Water Discharge BMPs

Land Use Domestic Public Domestic Public

Residential Commercial Institutional 50 75 10 10

Highway 100 150 50 75

Hotspot (gas station, etc.) Contaminated/Brownfield NPDES Permitted Industrial 100* 150* ** **

NOTE: Setback distances measured from 10-YR WSEL

*Generally discouraged but may be permissable with enhanced pre-treatment

** Maximize and evaluate on case-by-case basis


Take-Aways:

Most constituents found in urban stormwater runoff do not pose inordinate risk to source waters

The current and proposed DSSR follow EPA guidelines for protection of source waters

Properly designed infiltrating stormwater BMPs minimize potential impacts to source waters

Chlorides have greatest potential to negatively impact source waters, but data is lacking on the magnitude of the problem In meantime, chlorides best managed through source controls

Questions?

Randy Greer, PE

State of Delaware - DNREC

Division of Watershed Stewardship


89 Kings Highway

Dover, DE 19901

Ph: 302-739-9921

[email protected]

mailto:[email protected]

update to delaware sediment & stormwater regulations

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