ms4: pollutant reduction planning for impaired … · 2020-06-22 · you cannot claim in your prp...
TRANSCRIPT
MS4: POLLUTANT REDUCTION PLANNING FOR
IMPAIRED WATERWAYS
May 17, 2017
Pollutant Reduction Plan (PRP)
A plan developed to identify and then reduce a baseline amount of a
specific pollutant by some preset percentage (using various facilities,
BMP’s and programs).
Total Maximum Daily Load (TMDL)
The maximum amount of a specific pollutant that a waterbody can
assimilate and still meet WQ standards. Baseline has been pre-
established.
How is a TMDL Different from a PRP?
Chesapeake Bay Plan is a TMDL Plan (pollution diet)
Adopted in December 29, 2010 - Largest TMDL ever developed by EPA
Plan is to be completed by 2025, currently at the halfway point
(where 60% goals are to be met, Phase III Watershed Implementation Plan
(WIP’s) in progress) – Monday June 5th – Public Kickoff Meeting
6 States (and District of Columbia) participate in the TMDL Plan (by way of
WIP’s)
PRP’s become a tool to help shape and ensure successes for the
obligations of a WIP and the Bay TMDL
Chesapeake Bay TMDL
TMDL Limits are set at 185.9 million pounds of Nitrogen, 12.5 million
pounds phosphorus and 6.45 billion pounds of sediment (per year).
Overall watershed reductions for these limits are set at 25%, 24% and
20% respectively.
PA reduction goals are;
10% (Total Suspended Sediment)
5% (Total Nitrogen)
3% (Total Phosphorus)
Note:
In PA Permittees are encouraged to achieve the 10% sediment
reduction as this is expected to then result in the 5% and 3% reductions
Chesapeake Bay TMDL - Limits
How do I know if I have a local TMDL?
http://files.dep.state.pa.us/Water/BPNPSM/StormwaterManagement/MunicipalStormwater/Municipal_MS4_Requirements_Table.pdf
PRP Pollutant Reduction Plan – Impaired Waters
• If Impairment is sediment (Siltation) only, a 10% reduction is required.
• If Impairment is Nutrients only (or excessive algal growth, organic
enrichment/low DO), then a 5% Phosphorus reduction is required
• If Impairment is due to both sediment and nutrients, then PRP must
reduce sediment (10%) and Phosphorus (5%).
What does listed “impairment” mean for PRP?
Appendices (from Municipal Requirements Table)
Utilizing “Parsing” in PRP
Parsing for PRP – Optional process whereby land area is “removed” from the
loading calculations (if shown to not be of concern)
Note: Parsing for TMDL plans is a slightly different topic.
Why would you do this for PRP?
Reduces the pollutant loading and therefore reduces obligation for
reduction
Why wouldn’t you do this?
BMP’s in parsed areas cannot be included in PRP reduction calculations
Utilizing “Parsing” in PRP
Examples where Parsing may be appropriate;
Area of land is covered under an existing NPDES site (Industrial
Stormwater Discharge for example)
PennDOT (or Turnpike) rights-of-way
CAFO (already covered under NPDES)
Land area where stormwater does not contribute to MS4
Parsing can be “undone”…submit a “modified PRP” (same public hearing
applies)
Can I use existing programs or BMP’s to offset required reduction for
existing pollutant loading?
…but not as a direct “deduct”
Existing practices or BMP’s can ONLY be accounted for in PRP as
reduction in existing baseline.
What about existing BMP’s and Programs?
Example – Estimated loading of sediment is 1,000 pounds (per year) per
your PRP. To meet 10% reduction (or 100 pounds), PRP can propose that
an existing street sweeping program removes 50 pounds per year.
You cannot claim in your PRP that you meet half the annual goal by street
sweeping;
WHY???
1. Offset must come from baseline…PRP can claim 50 pounds per year
less as the starting point…950 pounds. Therefore 10% means now that
you need to only reduce by 95 pounds, not 100.
2. Side note: PA DEP does not allow street
sweeping to be the only BMP proposed to
reduce pollutants.
What about existing BMP’s and Programs?
Items needed to claim existing (structural) BMP credit in PRP;
• A detailed description of the BMP;
• Latitude and longitude coordinates for the BMP;
• Location of the BMP on the storm sewershed map;
• The permit number, if any, that authorized installation of the BMP;
• Calculations demonstrating the pollutant reductions achieved by the BMP;
• The date the BMP was installed and a statement that the BMP continues to
serve the function(s) it was designed for; and
• The operation and maintenance (O&M) activities and O&M frequencies
associated with the BMP.
(Source: PA DEP)
What about existing BMP’s and Programs?
Section A – Public Participation
Complete PRP must be available for someone to review
Advertise for public review (no less than 45 days prior to submission to
PA DEP) – provide copy of ad for PRP
Accept written comments (30 days from notice)
Address each noted concern and any changes made
What is required to be in a PRP?
Section B – Map
Develop map to show land uses, and/or impervious coverage
waterways
stormsewer shed to each outfall to impaired waterway or waterways noted in
Appendix D & E
Parsed areas
MS4 boundaries
Outfalls
Municipal Boundaries
What is required to be in a PRP?
Section C – Pollutants of Concern
• Note the pollutants being considered as part of the PRP (either by
Chesapeake Bay TMDL or by impaired waters (Siltation, Nutrients or both)
What is required to be in a PRP?
Section D – Determine Existing Loading for Pollutants of Concern
Calculating Pollutant Loads - Several Methods Available:
• (easiest) Simplified Approach
Obtain county specific loading rates
Determine impervious and non-impervious land coverage
(within UA area)
Apply rates to areas and calculate the loading
What is required to be in a PRP?
Simplified Approach for PRP’s
MapShed
Other Methods to Calculate PRP Loading
• Wiki Watershed
Other Methods to Calculate PRP Loading
Notes:
• User friendly to locate watershed and develop model
• Allows HUC 8/10 & 12 scale watershed analysis
• Web based platform (no proprietary software)
• Allows analysis on manually drawn drainage areas
(EPA) SWMM
Notes:
• Requires more extensive effort to build model
• Requires calibration
• Some loading calculations and efficiencies are flow volume based
Other Methods to Calculate PRP Loading
Section E – Select BMP’s to Achieve Minimum Required Reductions in
Pollutant Loading
Develop a “top down” calculation of how you will reduce pollutants;
- What new BMP’s or programs will community engage in to reduce loading
- Focus on “low hanging fruit” first (street sweeping)
- Other practices should look for most cost effective means (most ROI per
dollar spent)
• Avoid boutique BMP’s…low reduction, higher cost
• Stream restoration best one out there for reductions per cost
• Look for retrofits (larger facilities handling urban DA)
• Must be able to complete projects within 5 years (permit cycle)
• Use Effectiveness values provided by PA DEP.
• Use Expert Panel Papers to assist in calculating allowable reductions
- Continue reductions until full value is reached
What is required to be in a PRP?
Section F – Identify Funding Mechanisms
Feasibility of plan is evaluated by PA DEP (don’t promise the world)
• Look for partners, sponsors
• Look to outside limited term funding programs (grant or loan)
• Does not have to be guaranteed, but need to have backup plan if
funding option fails
What is required to be in a PRP?
Section G – Identify Responsible Parties for Operation and
Maintenance of BMP’s
• The party(ies) responsible for ongoing O&M;
• The activities involved with O&M for each BMP; and
• The frequency at which O&M activities will occur.
Annual Report will be mechanism to ensure activities are performed per
O&M
What is required to be in a PRP?
• Signing on for a 5 year program...spend time to make sure the plan fits
community
• Don’t delay and expect to “throw” one together 46 days prior to
submission
• Engage community, look for opportunities to partner (not just for
funding but for buy-in)
• Don’t be afraid to ask questions…lots of questions (even the
professionals don’t know everything)
Summary / Take Away