Update: Chesapeake Bay TMDL

August 2012 » Features » PROGRESSIVE ENGINEERING
Local and state governments refine Watershed Implementation Plans to reduce stormwater pollution.
Eileen Straughan
An enhanced nutrient removal project at DC Water's Blue Plains Advanced Wastewater Treatment Plant, slated to be finished in 2014, will reduce the amount of nitrogen in effluent to help meet Chesapeake Bay goals. Image: DC Water

On Dec. 29, 2010, the U.S. Environmental Protection Agency (EPA) established the Chesapeake Bay Total Maximum Daily Load (Bay TMDL), often referred to as the bay's "pollution diet," for nitrogen, phosphorus, and sediment. Since then, state and local governments in the bay watershed have been working to understand current pollutant loadings to the bay from all source sectors within their jurisdictions and just what it will take to achieve the reductions. Each state has been given its quota – the pounds of nitrogen and phosphorus, and the tons of sediment it may contribute to the bay on an annual basis.

To achieve these quotas and meet the water quality standards in the bay by 2025, each state must implement aggressive reductions incrementally across several pollution source sectors. It is no small task because, even within a state, no one entity has authority over all source sectors, and each sector is managed by different organizations with varying and often politically driven objectives. National Pollution Discharge Elimination System (NPDES) permits will be effective for limiting discharges from municipal and industrial wastewater treatment plants (WWTP), concentrated animal feeding operations (CAFOs), and Phase I/Phase II Municipal Separate Storm Sewer Systems (MS4s).

The first phase of Watershed Implementation Plans (WIPs) – the broad brush plans identifying how the reductions will be achieved on a state-by-state basis – were delivered to EPA in late 2010. More detailed Phase II WIPs were developed by the states in 2011. The Phase II WIPs are more specific about how the targeted reductions will be achieved and were prepared with significant input from local jurisdictions, particularly those with Phase I MS4 permits, which address pollutants from the urban stormwater sector. Jurisdictions with Phase I MS4 permits, such as Montgomery and Prince George's counties in Maryland and statewide agencies such as the Maryland State Highway Administration (MD SHA), have been leading the way in WIP development by necessity as each face changing MS4 permit conditions that reflect the stormwater sector pollutant load reduction requirements of the Bay TMDL.

Montgomery County's MS4 permit issued in February 2010 includes a requirement that the county:

  • retrofit an additional 20 percent of its existing uncontrolled impervious area with stormwater management (the county's previous permit included a 10-percent retrofit requirement);
  • restore/improve the water quality performance of existing stormwater facilities; and
  • demonstrate progress toward reducing loadings to achieve the TMDLs.

The county has determined that compliance will require design and construction of some type of stormwater retrofit for 4,300 acres of developed land – 3,800 acres at a county-estimated cost of $20,000 to $30,000 per acre (retrofit of existing structures) and 500 acres at a cost of $150,000 to $300,000 (new environmental site design/low-impact development (ESD/LID) facilities). The county has levied a water quality protection charge since 2003 to respond to its MS4 permit requirements. In 2003 the charge was $12.75 per year per equivalent residential dwelling unit. By 2011 the charge had increased to $49 and is projected to increase to $92 by 2013 to provide the funding necessary to comply with the MS4 requirements.

The Virginia Department of Transportation has developed a Watershed Implementation Plan that includes street sweeping to reduce nutrient and sediment pollution in stormwater. Image: istockphoto

Prince George's County also is a Phase I MS4 permit holder and anticipates, based on advice from the state, that it will face similar impervious area restoration/retrofit permit conditions when its MS4 permit is reissued. Prince George's County anticipates the need to retrofit an additional 20 percent of untreated impervious cover by 2017 and has completed its analysis of impervious surfaces. The county is analyzing what it will take to achieve the additional 20 percent retrofit requirement and indicates that to comply with its current permit condition to retrofit 10 percent and the additional 20 percent would require the county to design and construct stormwater retrofit facilities for 7,100 acres of impervious cover at an estimated cost of $45,000 per acre, and for an additional nearly 1,000 acres at approximately $64,000 per acre. Compliance with the MS4 permit is estimated to cost an additional $400 million between 2017 and 2025 to achieve the requirements of the Bay TMDL.

Similarly, the MD SHA is a Phase I MS4 permit holder and is anticipating substantial changes as its MS4 permit is reissued. MD SHA's Phase I MS4 permit area covers a substantial portion of the state, and the Phase II permit area will increase the area requiring retrofit requirements to encompass the state highways in 11 urban counties. Similar to Montgomery County's MS4 permit requirements, MD SHA anticipates it will need to provide 20 percent retrofit of its existing impervious cover, and is well underway with the analysis of its treated and untreated impervious cover and development of its own system wide TMDL compliance implementation plan. SHA estimates the cost to comply with the Bay TMDL at $700 million for engineering and construction, and $300 million for utility, right of way, and contingencies.

The District of Columbia is appealing its MS4 permit and development of an implementation plan has been stayed until the appeal is resolved. Once resolved, the District is planning to conduct a baseline analysis of pollutant loads, model various implementation scenarios, and with that information formulate the final implementation plan. While the cost for an urban stormwater retrofit program is unclear for the District right now, the costs for Bay TMDL compliance for upgrades to the Blue Plains wastewater treatment plant and implementation of the Long Term Control Plan (LTCP) for combined sewer overflows is very clear.

The NPDES permit for Blue Plains predates the Bay TMDL but nevertheless reflects its requirements. DC Water has completed design of Enhanced Nitrogen Removal Facilities (ENRF), which must be operational by 2015, and some components are ready for construction.

New framework to help local governments manage stormwater and wastewater In June, the U.S. Environmental Protection Agency (EPA) issued a new framework to help local governments meet their Clean Water Act obligations. The Integrated Municipal Stormwater and Wastewater Planning Approach Framework assists EPA regional offices, states, and local governments to develop voluntary storm and wastewater management plans and implement effective integrated approaches that will protect public health by reducing overflows from wastewater systems and pollution from stormwater. The framework document is available on EPA's website at http://cfpub.epa.gov/npdes/integratedplans.cfm.

The District reports that implementation of ENRF will cost $950 million. Implementation of the LTCP has a 20-year build out with an estimated cost of $2.6 billion and consists of construction of three tunnels to store combined sewer overflows (CSOs) for eventual treatment at the Blue Plains plant. The District is currently under Consent Decree to implement the LTCP but is requesting additional time to implement and demonstrate the effectiveness of LID retrofits as a means of driving down the size of the tunnel storage facilities. Because LID retrofits would have significant nexus with the MS4 permit requirements, it seems like a highly effective strategy for the District.

The Maryland State Highway Administration estimates the cost to comply with the Chesapeake Bay Total Maximum Daily Load at $700 million for engineering and construction, and $300 million for utility, right of way, and contingencies. Image: istockphoto

Arlington County, Va., is responding to load-reduction targets with urban stormwater management retrofits, street sweeping, stream restoration, and reductions in pollutant loading accompanying redevelopment. To develop its implementation plan, the county looked at various best management practices (BMPs) and costs and concluded that compliance with the NPDES permit would require $50 million in funding to implement.

Fairfax County, Va., estimates its cost of compliance with the Bay TMDL at $845 million. Implementation projects will include stream restoration, outfall restoration, existing detention basin retrofits, and ESD/LID.

The Virginia Department of Transportation (VDOT) has no impervious surface retrofit requirement in its current MS4 permit but recognizes that its permit renews in 2013 and is engaged in addressing nutrient and sediment reductions to achieve the Bay TMDL. VDOT has developed a WIP that includes street sweeping (6,500 acres per year), increased implementation of erosion and sediment control on disturbed sites (1,500 acres per year), construction of extended detention dry pond stormwater retrofits (140 acres per year), and filtration devices (20 acres per year).

There are some similarities among the jurisdictions responding to the Bay TMDL. Most have a pretty good understanding of the characteristics of their portion of the watershed in terms of land use and impervious cover and are using models to help them estimate pollutant loads and evaluate alternative compliance scenarios in terms of efficiency and cost. However, urban stormwater is only one of the source sectors. Jurisdictions also are implementing nutrient-reduction strategies through WWTP upgrades and implementing major projects to control CSOs; all recognize the significant need for outreach to help the public understand the need for these projects.

The estimated costs of compliance with ever more stringent NPDES permit conditions fall to the local jurisdictions, utilities, and agencies that hold the permits. Although there is grant money available to fund some of the projects, there is not nearly enough. Recognizing that most Maryland counties had no mechanism in place to cover the costs of stormwater infrastructure, the Maryland General Assembly passed legislation in its 2012 session requiring counties with Phase I MS4 permits to adopt and implement laws or ordinances to establish a watershed protection and restoration program that includes a stormwater remediation fee and a local watershed protection and restoration fund by July 1, 2013. The public is accustomed to paying for potable water and wastewater treatment services, but the idea of paying a fee to clean up stormwater is new. A fundamental change in the public's understanding of watersheds, stormwater, pollution prevention, and stormwater management will be required to achieve the objectives of the Bay TMDL.

The public is accustomed to paying for potable water and wastewater treatment services, but the idea of paying a fee to clean up stormwater is new.

Maryland Department of the Environment developed Maryland's Assessment Scenario Tool (MAST) to help local jurisdictions evaluate different strategies to achieve compliance with the required pollutant load reductions. Other proprietary software tools are being developed commercially to help jurisdictions develop and evaluate the most cost-effective strategies to achieve compliance. But success in achieving healthy waters in the Chesapeake Bay and other surface waters targeted for implementation of a watershed-based approach to compliance with the Clean Water Act, may reside more in an ability to manage adaptively and link actions taken to water quality outcomes measured in the receiving water. Establishing a valid link requires scaleable integration of plans, programs, and data – much of which resides in silos throughout state and local government and non-governmental organizations – and closer collaboration between information technology and watershed science professionals.

Eileen Straughan, president and founder of Columbia, Md.-based Straughan Environmental (www.straughanenvironmental.com), has almost 30 years of experience in environmental science, planning, and design for transportation and land development projects. In addition, she recently was appointed president of the board for the Center for Watershed Protection.


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