The proposed 0.28 lb/ac/yr standard corresponds with a ~10% level of imperviousness, a 37% reduction in the previously allowable level of discharge.  On the previously mentioned example (70% impervious), this single change would require a phosphorous removal rate of ~83%, increased from ~73%. Though the amount may seem incidental, this represents an exponential increase in treatment requirements on a site since “treatability” approaches zero as the required treatment level approaches 100%.

 

There are two ways to meet the proposed regulation:

 

First is by on-site mitigation…wet ponds, dry ponds, biofilters, cisterns, pervious pavers, and the like. While the new calculation methods (giving credit for “Runoff Reduction” in addition to “Treatment”) appear to give alternatives meeting the phosphorous removal requirements, however the higher removal methods generally require a comparably high amount of maintenance to perform as intended. Without proper maintenance and with these methods being the primary treatment method rather than the secondary (biofilters in series with a traditional wet/dry pond, for example), the end result will be more pollution in the stormwater discharge. This is a problem the industry hasn’t even begun to grapple with and will be a very significant problem in the next decade.

 

Second is by increasing land area devoted to a particular project. For a couple of random example projects analyzed for this comment letter, the land area devoted to a particular project must increase by 40% to over 60% simply to offset the change in allowable phosphorous discharge. This is real land area and real results based on analyzing three prominent Fredericksburg area commercial development projects ranging from 20 acres to 45 acres. In real terms, one of those projects was 25 acres…it would increase to 38 acres, 13 of which are deemed undevelopable, in order to set aside sufficient open space to offset the requirements of the proposed policy. Obviously, this is unreasonable and undesirable in any setting and this type of intentionally inefficient development is, in effect, the very definition of sprawl.

 

As an aside, the inclusion of “Table 1: BMP Pollutant Removal Efficiencies” and citation of the “Virginia Stormwater BMP Clearinghouse” website all but dismisses the Virginia Stormwater Management Handbook (The Blue Book) and creates an entirely new standard in stormwater management calculation, credit, implementation, and maintenance. Perhaps it would be prudent to place a critical eye on the treatment methods provided on this web page. The “Dry Swale” taken as an example, would appear to be a simple, effective alternative to a traditional stormwater management facility. Placed in an office/commercial/high-density setting (as pictured), however, would all but require the use of weed killers and nutrient-rich fertilizers to provide a safe and aesthetically pleasing appearance. The picture on Sheet 3 of 20 in the draft DCR Design Specification #10 (just above the “Section 1” heading) certainly is NOT the product of free/wild growth of tall meadow grasses…this example is absolutely the result of regular turf management (including irrigation and nutrient treatment) to maintain an ordered appearance. This is but one of the many examples of counterintuitive application of alternative stormwater management systems that appear sound, but in application will be far worse for the Chesapeake Bay.

 

In the end, commercial development is a very small slice of the pie. In the Rappahannock River Basin, for example, commercial/urban phosphorous discharge per acre has been approximately 30% lower than agricultural discharge rates.  Combine that with the fact that there is approximately 4 times the land designated as “Agricultural” than “Urban”, and it would quickly seem that commercial/urban development is paying an unreasonably high “tax” to solve the Bay’s issues.

 

Put another way, using round numbers, it would take a 16% reduction in agricultural pollution discharge to offset ALL (100%) of the current phosphorous discharge from ALL (100%) of the commercial/urban development in the Rappahannock River Basin. I’ll say that again: To make it as if there is ZERO urban development in the Rappahannock River Basin, only a net 16% reduction in phosphorous load from agricultural land would need to be achieved. 

 

This immense reduction in agricultural discharge could be achieved by numerous methods stated in the afore mentioned Table 1. Taking the nominal treatment credit of 50% for a seemingly appropriate treatment method, Sheetflow to Filter/Open Space, a mere 1/3 of agricultural land would need to be fitted with this treatment method. This is to offset ALL URBAN DEVELOPMENT, remember. Of course, to offset 10% of all urban development (FAR beyond what even this current proposal could achieve), NOT EVEN 4% of agricultural land would need a 50% efficient management device.

 

Given these facts, which makes more sense? Placing an onerous requirement on commercial developers, diminishing the main tax base for most municipalities in the state (and the state itself, for that matter)? Or allowing the development community continue with the effective current standard of stormwater management and pay into a state fund, as others have suggested, to make real progress by treating more agricultural discharge? The developers are still paying to fix the bay, but let the money be spent where it NEEDS to be spent…where the pollution is.

 

I am a lifetime Coastal Virginia resident and grew up pulling blue crabs from a single pot at the upper reach of the Poquoson River. I still enjoy fishing on the Chesapeake Bay and fully support sensible regulation of discharge into the Bay. I have been a practicing Engineer in the Chesapeake Bay watershed, providing site plan documents for commercial development my entire career and have a direct impact on the stormwater discharges from the projects I work on. There are no shortcuts. Responsible engineering, development, and construction is fundamental to making the current standards work. Commercial development is an easy place to continue to place blame, but as an engineer, scientist, and resident of the Chesapeake Bay Watershed, I am fully and completely convinced that the same or less money spent at the RIGHT locations would have a far more beneficial impact on the Chesapeake Bay than these proposed regulations.