Brewer’s Pond Shoreline Protection Project

Brewer’s Pond Shoreline Protection Project

Annapolis, Maryland

The Brewer’s Pond Natural Area hosts eight different habitat types: uplands and steep slopes, ravine bottom, shrub swamp, floodplain forest, wooded swamp, tidal cove, tidal tributary, and tidal wetlands.  The habitats mesh together seamlessly and represent a fully functioning ecosystem that provides critical habitat to the native species of the region.  Of particular interest in the Brewer’s Pond Natural Area is the area’s namesake: Brewer’s Pond.  Brewer’s Pond is one of the few remaining undisturbed tidal tributaries to the Severn River.  The shallows depths and constrained opening restrict boat access and have preserved the pond as a refuge for natural species, many of which depend on tidal tributary habitats as part of their life cycles.

As determined by the National Marine Fisheries Service, Brewer’s Pond is essential fish habitat to windowpane flounder (Scopthalmus aquosos), blue fish (Potatomus saltatrix), summer flounder (Paralicthys dentatus), red drum (Sciaenops ocellatus), king mackerel (Scomberomorus cavalla), Spanish mackerel (Scomberomorus maculates), and cobia (Rachycentron canadum).  Field survey conducted by Biohabitats in September 2014 found that tidal marsh borders the sand peninsula that separates Brewer’s Pond from the Severn River and supports additional native species of flora and fauna, including smooth cordgrass (Spartina patens) and high-tide bush (Iva frutescens).  Two species of submerged aquatic vegetation, widgeon grass (Ruppia maritime) and redhead grass (Potomogeton perfoliatus), grow in the nearby waters.

In their natural state, tidal coves such as Brewer’s Pond serve as a refuge and nursery for small aquatic prey such as juvenile fish, crabs, and turtles.  Deeper and wider channels allow increased numbers of large piscivorous fishes, which can adversely affect nursery and recruitment functions.  Furthermore, larger openings allow for increased wave influence, which can degrade habitat through wave-induced shoreline erosion, increased sediment suspension, and declines in water quality.  Increased flow between the pond and the river can also change the character of the pond by increasing salinity or decreasing oxygen concentration.

Unlike Brewer’s Pond, the mouths of many neighboring tidal tributaries have been dredged for navigable access.  As one of the few remaining natural tidal coves, it is paramount to protect the character of Brewer’s Pond from direct or indirect human influence and preserve the area in its natural condition to the greatest extent possible.

The need to protect Brewer’s Pond was first identified in 1994 when significant erosion caused by indirect human influence threatened the shoreline of the peninsula separating the pond from the Severn River.  A plan was developed by Flood Brothers Marine Consultants that intended to protect the shoreline from erosion and promote tidal marsh by armoring the shoreline with 1,800 feet of stone breakwater.  This plan was constructed in 1995 and continues to perform as intended with the exception of a 300-foot length near the southern end of the peninsula that was noted to be suffering from erosion in 2004 with significant erosion noted by 2010.  Despite the breakwater remaining stable in this narrow section of the peninsula, breaching of the breakwater by natural waves and boat wakes had eroded the tidal marsh below mean low water – essentially carving a new opening to Brewer’s Pond.  It was determined that, without intervention, this erosion would continue to the point of threatening the unique circumstances of Brewer’s Pond that support its ecological importance.

In 2012, a low impact sandbag dike was constructed as an interim measure of protection in the area of erosion. This effort, as expected, failed to protect the shoreline over the long term and in 2014 Biohabitats began development of a comprehensive solution.   After research and observation, Biohabitats proposed a hybrid living shoreline approach which included restoring both high marsh and low marsh area, augmenting the existing revetment, and stabilizing the pond edge of the shoreline.  This plan was designed to preserve the maximum amount of existing tidal marsh, provide additional aquatic habitat, and restore ecosystem processes and functions.  This design called for the augmentation of the existing stone breakwaters along with imported sand substrate between the existing marsh and breakwater to support high and low marsh plants.  Coir logs lined the pond edge of the project area to stabilize and retain the imported sand.   The elevation and width of the tidal marsh to south of the eroded section is hypothesized to have allowed this section to resist erosion, and as such the design called for the imported area of sand to match this width and elevation.  Following construction, native plant species are planted to further stabilize the project and jumpstart ecological benefits.

Underwood & Associates was selected to construct the project in late 2016, and completed the project during March of 2017.  Following construction, six native species – Atlantic white cedar (Chamaecyparis thyoides), seaside goldenrod (Solidago sempervirens), cardinal flower (Lobelia cardinalis), sturdy bulrush (Scirpus robustus), smooth cordgrass (Spartina alterniflora), and salt meadow hay (Spartina patens) – will be planted across the project site, each placed according to its preferred habitat.

This project is expected to protect the highly valuable natural resource that is Brewer’s Pond for many years to come.  It would not have been possible without the combined efforts of all parties involved – specifically Anne Arundel County Department of Public Works, Biohabitats, Sherwood Forest, and Underwood & Associates each contributed important components.