As previously noted in our September posts, PA DEP has convened a BMP Manual Revision Committee. In their notification to attendees, they noted that

… recommended updates may include edits to existing portions, complete omissions, or additions of new material.  All changes much be justified through acceptable principles of engineering or science.  If unable, to do so, subgroups may bring new ideas before the bigger committee for consideration and feedback.

Following is PA DEPs statement on the focus of this  Sub-Group, as presented at the first Committee Meeting:

Pennsylvania’s PCSM program has been set up in a way that focuses on volume control first.  Water quality has been determined to be inherent in volume control (with some consideration given to impacts from solute/nitrates)  There are many projects that, for one reason or another, are unable to achieve the Department’s volume control guidelines.  In those instances, more focus is given to water quality compliance.

1. Does the group believe that the 85, 85, 50 approach for surrogate parameters (TSS, P & N) is still the right way to go?  If not, then what other approaches are recommended?
2. Does the group believe that worksheets 10 through 13 are adequate for water quality compliance?  Are there recommendations for improvements or changes?
3. Do we want to continue with % pollutant removal for BMP performance?  What feasible alternatives are there for BMP Performance? (i.e. Volume, Concentration and Total Load)
4. Are there alternatives to using EMC?  If not, what new numbers do we have for the EMC and pollutant reductions that are listed on DEP Worksheets 12 and 13?
5. PA needs a WQ BMP sizing criteria.  Designers can not take the same % pollutant removal for a BMP receiving 1 acre of drainage compared to another receiving 5 acres.  There is currently no set criteria for this.  Perhaps a “loading ratio” approach would be appropriate here.  (perhaps even more so than for infiltration BMPs)
6. What new guidelines should we have, if any, for nitrates? (i.e. source control, fertilizer reduction, etc.)  Is there a minimum buffer width (or filter strip width) that we can say that nitrates (as well as TSS and P) are addressed?
7. Do we need to define a water quality storm in PA, as has been done in other states?  If so, what should it be and why?
8. Like it or not, manufactured products play a significant role in SWM. What are the gaps and how can they be addressed?  Should PA fully adopt the verification process (NJCATs) that has been developed for manufactured WQ BMPs?    If not, how can PA beef up its verification process for water quality BMPs?  How can PA establish a level playing field for manufactured products?  (In many cases, these products are swapped after permit issuance due to value engineering and regulatory agencies are put on the spot to grant approvals)
9. Should we be putting land based water quality BMPs (such as rain gardens) through a similar process as manufactured products to verify BMP performance?  If so, why and how?

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