COASTAL PONDS

Martha's Vineyard is fortunate to have 27 coastal salt ponds including nearly 9000 acres of surface area. Many of these are Pond Data Summary (GreatPonds 76K) (10 acres or more in size) that are located all around the Island. Of these, there are 8 south shore ponds that are periodically tidal, such as Edgartown Great Pond, Tisbury Great Pond, and Chilmark Ponds. These ponds are broad and shallow, with large watersheds and transitory openings to the Atlantic Ocean. Another 8 coastal great ponds are almost always fresh. There are 14 other coastal great ponds that are continuously tidal. Some, such as Lagoon Pond and Lake Tashmoo, are long, narrow and deep, with fixed inlets and smaller watersheds.

At the heart of the Commission's planning program is research by the Commission's professional staff, funded by various external sources and supported by Town Shellfish departments. Commission staff investigates and monitors various water column parameters in the ponds that are indicators of system quality. Data from the Commission's research endeavors is used as the basis for sound planning and management of the valuable resources of the ponds.

Partnerships are key to the Commission's role in stewardship of the great ponds. The Commission provides assistance to the towns in preparation of policy documents to manage the coastal ponds of each town and those shared between towns. The Commission also partners with various pond advocacy groups and other non-profits.

The Commission's regulatory involvement includes establishment of Districts of Critical Planning Concern (DCPCs), and some project review on a case-by-case basis.

RESEARCH—ASSESSMENT AND MONITORING

Excellent water quality is key to the viability of most pond uses. Water quality in many of the great ponds on Martha's Vineyard has not been seriously compromised. Due to their restricted circulation, water quality in the south-shore great ponds is not as pristine as in the fully tidal ponds. However, there are opportunities still available to reduce future impacts from nutrient sources.

The tidal great ponds are important shellfish resources and support large eelgrass beds. Periodically they are subject to lower water quality that may be influenced by a combination of factors including inadequate circulation, on-going nitrogen loading and even the weather.

Commission staff has engaged in significant research of the coastal resources of the great ponds on Martha's Vineyard since 1995.

• Watershed-based nutrient loading assessment
  Commission staff has gathered and evaluated land use data for the watersheds of most of the major ponds, in order to identify the Water Quality and Nutrient Loading (PondNutrientLoad 244K) .

• Tidal flushing and circulation investigations
  Commission staff has performed bathymetric and tidal measurements in order to determine Pond Flushing and Residence Time (PondFlushResidenceTime 66K) for most of the great ponds.

COASTAL SYSTEM RESTORATION

Eelgrass is a crucial component of the coastal ponds providing protected nursery sites for fish species, bay scallops, Blue Crab Report (BlueCrabs 1.9M) and other important marine species. Eelgrass needs light in order to thrive. Where NutrientLoad [document not yet available online] is substantial, phytoplankton, slime coating algae known as Epiphytes & Wrack Algae (Epiphytes 159K) and large Wrack Algae (WrackAlgae 159K) growth may reduce the light and cause a decline of eelgrass. Sengekontacket Eelgrass,1 (EelgrassBeds 569K) have been found to be shrinking in most of our coastal ponds (see DEP_CostelloMaps [document not yet available online] ).

The Commission has conducted detailed studies of the health of the eelgrass beds in Tashmoo, Sengekontacket and Farm Ponds (see Survey of Eelgrass, Lake Tashmoo (TashmooEelgrassSurvey 2.8M) ). Our study included mapping the extent of the beds, measuring plant density within the bed and evaluating the mass of epiphytes (see Epiphytes & Wrack Algae (Epiphytes 159K) and Wrack Algae (WrackAlgae 159K) ) growing on the plants in the system. We also inspected the plants for wasting disease, the cause of the loss of eelgrass throughout the northeast in the 1930's. (Wasting disease is caused by a slime net organism that causes leaf spots that coalesce and eventually kill off the entire blade (see Link9 [document not yet available online] ). In the ponds studied, we have found the disease to be present but at a low, background level. The disease is encouraged by any stress to the plants such as loss of available light. In an attempt to restore eelgrass to ponds where it has disappeared, the Commission has begun small-scale, trial eelgrass restoration projects in Sengekontacket and Edgartown Great Ponds.

WATERSHED-BASED MANAGEMENT

The Island's coastal ponds have long been used for shellfishing and for various recreational pursuits. Without proper stormwater management and growth management in the watersheds of the ponds, water quality and habitats could easily be degraded. It is far easier to prevent degradation than to try to reverse decline or live with the consequences. Conflicting uses on the ponds must also be managed properly, especially considering the impacts of boating.

NUTRIENT LOADING LIMITS

Commission staff has used nutrient loading assessment data, with tidal flushing data, to set interim limits for nutrient loading to a number of great ponds on the Island, and has projected land use at buildout in order to compare the projected nutrient load to the limit. (See Link22 [document not yet available online] , Link23 [document not yet available online] , Link24 [document not yet available online] , Link25 [document not yet available online] and Link26 [document not yet available online] ).

PARTNERSHIPS/COLLABORATION

On Martha's Vineyard, stewardship of coastal lands and waters is usually a cooperative effort between government agencies, partnered with local advocacy groups and non-profits. The Commission provides a number of services to foster good cooperation and good stewardship of coastal resources.

POND ADVOCACY GROUPS

The Commission recognizes and lauds the efforts of the various local pond advocacy groups groups that focus attention on pond issues. Some groups have funded research and other initiatives. They are of particular value for ponds that are shared between two towns (as most are), helping to unite all the stakeholders regardless of town boundaries.

ALL-ISLAND CONSERVATION COMMISSIONS

The Commission facilitates quarterly gathering of the six Island Conservation Commissions (except for summer), to share information and ideas about issues common to all.

WATERSHED TEAM

Commission staff participated in the Commonwealth's Watershed Initiative and regrets its demise. It is hoped that the local partners will continue this valuable collaboration on some level.

TOWN SHELLFISH DEPARTMENTS

Commission staff has partnered with the Shellfish Wardens to sample most of the tidal great ponds and many of the south shore great ponds in order to define the water quality of these systems. The Wardens are a crucial aspect of the sampling program logistics.

MASSACHUSETTS ESTUARIES PROJECT

This program will provide the most scientifically advanced analysis of our coastal great ponds to determine their water quality and their ability to tolerate the current and future expected nitrogen load from their watersheds. The Commission and Shellfish Wardens are full partners in the 3-year process to prepare a pond for entry into this program and the two-year evaluation. (See Massachusetts Estuary Project: Embayment Restoration and Guidance for Implementation Strategies, 2003.)

ASSISTANCE TO TOWNS

Commission staff is always ready to assist the towns, upon request, with their own policy plans.

REGULATORY ROLE OF THE COMMISSION

• Several Districts of Critical Planning Concern have been designated to protect the Island's great ponds. The DCPCs serve to protect the most critical resources of each pond. Pond DCPCs include: Coastal District, Lagoon Pond District, Sengekontacket Pond District, Squibnocket Pond District, Edgartown Great Ponds District, Cape Poge District, Menemsha, Nashaquitsa and Stonewall Ponds District (see current DCPCs).

• The full Commission reviews a number of development projects in the watersheds of the great ponds as Developments of Regional Impact.

• Commission staff reviews many projects in conjunction with MEPA and DEP Waterways licensing.

COASTAL POND RESOURCES

STAFF CONTACTS

Jo-Ann Taylor, Coastal Planner, ext. 19, taylor@mvcommission.org

William Wilcox, Water Resources Planner, ext. 17, wilcox@mvcommission.org

MVC PUBLICATIONS

USEFUL LINKS

• Local contacts such as Pond advocacy groups
• Buzzards Bay, Waquoit Bay and Chesapeake Bay programs
• Massachusetts Estuaries Project
• National Estuary Program
• Save the Bay
• NOAA National Ocean Service tides