The Chesapeake Bay TMDL – the largest ever developed by EPA, encompassing a 64,000-square-mile watershed – identifies the necessary pollution reductions from major sources of nitrogen, phosphorus and sediment across the District of Columbia and large sections of Delaware, Maryland, New York, Pennsylvania, Virginia and West Virginia. The TMDL sets pollution limits necessary to meet water quality standards in the Bay and its tidal rivers.

Each of the major Bay jurisdictions has developed large scale strategies—called Watershed Implementation Plans or WIPs- to meet overall basin pollutant load allocations. Phase II of the WIP process required more detailed planning by municipalities to demonstrate how each will do their part in improving the water quality of the Chesapeake Bay and its tributaries. A critical component necessary to refine these broad strategies is assessment of the watershed to identify suitable locations for the proposed water quality practices.

Wicomico County’s Strategy for Restoring the Bay

Wicomico County and the City of Salisbury are located on the Eastern Shore of Maryland within the Chesapeake Bay drainage. The Center for Watershed Protection provided assistance to the County and City last year to develop their WIP strategies for addressing urban stormwater runoff. The urban portion of the WIP was developed based on discussions with key staff, limited GIS analysis, and modeling using the Maryland Assessment and Scenario Tool (MAST). The required nutrient reductions, BMPs selected to achieve the reductions, and estimated cost to the County and City are shown below.

Jurisdiction	Reductions Required by 2025 (lbs)		BMPs	Cost ($millions)
	TN	TP
Wicomico County	48,303	4,948	new BMPs, retrofits of existing ponds, street sweeping, urban nutrient management, and stream restoration	$694.5
City of Salisbury	12,496	1,447	new BMPs, retrofits of existing ponds, street sweeping, urban nutrient management, vegetative open channels, and stream restoration	$227.2

The selected urban BMPs are ones that are currently approved by the Maryland Department of the Environment and the Chesapeake Bay Program. Alternative BMPs and proposed revisions to the nutrient reduction efficiencies are regularly reviewed by the Chesapeake Bay Program. Any changes could substantially affect the WIP strategies that are ultimately implemented as well as their associated cost.

The approach outlined by the City and County represent planning level efforts as opposed to a detailed roadmap for implementation. The next critical step in this process is to identify the location of the proposed BMPs and further refine the strategies (and costs) based on the feasibility of implementation and identification of high-priority restoration projects. The County recommended that additional analyses be provided through watershed planning efforts for the three major watersheds within its jurisdiction: the Nanticoke River, Wicomico River, and Pocomoke River watersheds.

Wicomico River Watershed Planning Initiative

The Center, working with partners from the City of Salisbury and Wicomico Environmental Trust, prepared a Watershed Management Plan for the Wicomico River watershed, in part to support refinement of the WIP. The 230 square mile watershed drains to the Tangier Sound and ultimately the Chesapeake Bay and includes a very small portion of Sussex County, Delaware with the majority contained in Wicomico County and Somerset County, Maryland. Major land uses in the watershed include agriculture (27%), wetland (25%), forest (18%), and developed (15%).

Photo by Winona Hocutt

A core team was established to guide the formation of watershed goals and objectives and to oversee development of the plan. Three public stakeholder meetings were held to educate the public and seek input on various aspects of the plan. An initial task in developing the plan was to develop an understanding of the baseline, or current, conditions in the watershed. Due to the large watershed size, a Comparative Subwatershed Analysis was conducted to broadly characterize subwatersheds according to their restoration potential and priority for protection. Two of the top-ranked subwatersheds were selected to conduct more detailed restoration assessments that would ultimately help to refine the County and City’s WIP strategies.

Identifying Restoration Opportunities to Achieve Water Quality Goals

The Center and its partners conducted extensive stormwater retrofit, upland and stream assessments with the help of volunteers throughout two Wicomico subwatersheds – the South Prong and Tony Tank. The goal of the assessment was to evaluate the feasibility of implementing water quality management or restoration practices. Field crews visited over 352 locations in the watershed to evaluate sites using the Retrofit Reconnaissance Inventory, Hotspot Site Investigation, Neighborhood Source Assessment, and Unified Stream Assessment. Approximately 135 potential stormwater retrofit sites, 44 potential hotspot locations, 47 residential neighborhoods and 13.4 miles of stream were assessed. Common problems observed included a lack of stormwater management at older development sites, inadequate stormwater treatment at some sites, improper outdoor material storage and waste management, inadequate riparian buffer areas, and trash.

As a result of the field evaluation, 11 major watershed restoration strategies were identified for the two subwatersheds, focusing on a range of activities such as municipal practices and programs, natural resources protection, treatment of polluted runoff, and pollution source control. More than 290 opportunities for specific restoration projects were identified and prioritized through a ranking process. The proposed projects include a mix of bioretention, wet ponds and wetlands, impervious surface reduction, urban tree planting, urban nutrient management, forest buffers, stream restoration, dry swales, retrofit of existing ponds, regenerative stormwater conveyance, filtering practices, and infiltration. The stormwater retrofits alone would treat approximately 289 acres of impervious cover and 540 acres of pervious cover.

The cumulative estimate for implementing the recommended stormwater retrofits was $10 million dollars. Using MAST, these projects were estimated to reduce 3,244 pounds of nitrogen and 382 pounds of phosphorus. This equates to achievement of 1.3% of the combined County and City nitrogen reduction targets and 2.6% of the phosphorus reduction targets. Given that the two subwatersheds assessed represent 13% of the total County and City area, there is still opportunity to make up the difference by applying urban BMPs in the remaining subwatersheds. It is likely that the cost to achieve these reductions can be significantly reduced as more cost-effective BMPs are approved by the Chesapeake Bay Program through its Protocol for Development, Review and Approval of Loading and Effectiveness Estimates for Nutrient and Sediment Controls. BMPs identified for review through this process and the status of each review is available on the Chesapeake Stat website. The County intends to revise its WIP strategy (and cost estimates) upon the completion of additional watershed assessments to reflect feasibility and make adjustments needed to reach the 2025 targets.

It’s Not All About Restoration

While the watershed planning effort fulfills a need to identify restoration projects that will help to achieve Chesapeake Bay water quality improvements, another important goal of the field assessments was to identify priority conservation areas within the subwatersheds evaluated. A desktop assessment first identified conservation priorities such as habitat for rare, threatened and endangered species, rare natural community types, and ecologically important lands for conserving Maryland’s biodiversity. Protected lands were also identified with the rationale that important conservation areas adjacent to already protected lands should be prioritized for protection to promote habitat connectivity and provide for larger green infrastructure hubs and corridors. Field assessment identified some additional site with high quality stream and riparian habitats. Ultimately, seven sites were determined to be top priority for conservation.

Project partners are successfully moving forward with implementation and additional planning efforts. Three projects are currently being planned including a bioretention / living shoreline, buffer enhancement and trash removal / tree planting. A grant has been submitted to conduct a field assessment in the North Prong Subwatershed and funding will be sought to conduct conservation area assessments and identify agricultural and roadside BMPs in the four subwatersheds designated for protection efforts.

The Wicomico River Watershed plan will be available in the near future from the Wicomico Environmental Trust website. For more information about the plan, contact Lori Lilly, Watershed Ecologist/Planner at the Center for Watershed Protection, at lal@cwp.org or 410-461-8323.

Funding for this work was provided by the National Fish & Wildlife Foundation and Chesapeake Bay Trust.