MODERATOR: Adrienne Kotula
Identifying the most Cost-Effective BMPs for Improving Water Quality and Maximizing Co-Benefits
Best management practices (BMPs) must be implemented to reduce nitrogen, phosphorus, and sediment loads in order to meet the requirements of the Chesapeake Bay Total Maximum Daily Load (TMDL). To support these efforts, we developed estimates of nitrogen, phosphorus and sediment reduction effectiveness and cost per unit reduced for each BMP using CAST. CAST is the Chesapeake Bay Program Phase 6 model. Using a series of BMP “isolation” model scenarios, we determined the pounds of nitrogen, phosphorus, and sediment reduced for each BMP. The design of the scenarios isolates the load reduced from each BMP while including the interaction effects of other BMPs, and is useful for assessing relative differences among BMPs. The annualized cost per pound reduced per year may then be calculated using available estimates of unit cost per BMP. This information can enable the targeting of the most effective BMPs at the lowest cost. Co-benefits of implemented BMPs were explored using qualitative impact scores developed for the Chesapeake Bay Program to support integrated implementation for multiple Chesapeake Bay Program Partnership management strategies. The ability to tie the same action, or BMP, to multiple objectives facilitates program and funding prioritization and may result in a greater likelihood of implementation. Using a small watershed, we illustrate the potential to reduce costs, improve nitrogen and phosphorus reductions, and impact co-benefits.
Leveraging and Upgrading Private BMPs for Mutual Public/Private Benefit
- David Hirschman, Principal, Hirschman & Environment, LLC
Previous studies have demonstrated that retrofit of existing BMPs is one of the most promising and cost-effective approaches to achieving TDML pollutant reduction goals. While many retrofits have taken place on public land, it is much more challenging to implement retrofits of privately owned BMPs. However, in Albemarle County, as well as many other Bay jurisdictions, these private BMPs represent many more facilities and many more acres treated than a public-only approach to retrofitting. Under a NFWF grant, Albemarle County and the Center for Watershed Protection piloted a system to identify and prioritize the retrofit of private BMPs, examined methods to reach out to and engage private BMP owners, developed concept plans for private BMP retrofits to be constructed as part of implementing a County private BMP retrofit program, and fed into the eventual implementation of two retrofits – a bioretention retrofit of a dry detention pond, and a stream restoration that spanned a municipal boundary and offered a shared and split pollutant removal credit scenario. The workshop format will be a mix of presentation, small group and interactive activities, and whole group discussion. We will cover the prioritization method, landowner outreach, implementation methodology, the results (in the presentation), and perhaps most importantly, lessons learned including (but not limited to) managing expectations with a lot of uncertainty, and leveraging partnerships.
Evaluating Opportunities for Public/Private Partnerships with Non-Profit Organization Property Owners to Increase Stormwater Management in a Fully Developed Municipality
The City of Falls Church, Virginia is expected to meet the stormwater pollutant load reductions identified in Virginia’s Chesapeake Bay WIP as defined in VPDES MS4 permits. The City has implemented an annual Stormwater Utility (SWU) fee to fund these efforts. The National Fish and Wildlife Federation provided GKY a technical assistance grant to evaluate the interest in forming public/private partnerships (P3) between non-profit organizations (NPO) and the City. GKY identified 19 NPOs who own 27.8 acres (19.6 acres impervious). NPO owners of 18.5 acres (13.0 acres impervious) expressed interest in participating in the study. Site evaluations determined that retrofit opportunities were limited due to 1) the intense density of existing development; 2) the shallowness of the receiving public stormwater infrastructure; and, 3) the relatively small drainage areas associated with potential retrofits. The opportunities that were identified represent annual pollutant reductions to the Chesapeake Bay of 53.35 lbs. for nitrogen; 7.83 lbs. for phosphorus and 4,442.65 lbs for sediment. The estimated design and construction costs for the identified retrofits totaled $2,959,251, with the costs per pound of pollutant removed averaging $55,479 for nitrogen; $377,938 for phosphorus; and $666 for sediment. NPO savings from the potential annual SWU credits ranged from $47 to $1,332. In implementing a P3 that is effective at attaining pollutant reduction while operating cost-efficiently, the City’s P3 must: 1. Provide substantive incentive packages for participants; 2. Take advantage of the economy of scale; and, 3. Maximize benefits to the City.