Vineyard water is abundant and in need of care
Over the past generation, rapid growth on the Vineyard has heightened concerns about how to ensure that the quantity and quality of the Island's water resources remain sustainable. Though many variables are involved, one conclusion is inevitable: if we do not act to protect Island water resources, what we now take for granted will be forever lost.
Impacts to the drinking water, to our coastal ponds, and to inland freshwater ponds and streams have a tremendous effect on our way of life. Even the slightest degradation to these natural resources has a direct impact on our economy, recreation, and daily appreciation of our surroundings. Take a moment to consider the Island without suitable drinking water or without shellfishable waters. Next Wednesday, the Island Plan Work Group on Water Resources invites the community to engage in a conversation abut these issues and review the draft document composed to address these concerns.
Drinking Water. When it comes to drinking water, Martha's Vineyard has a plentiful supply of fresh groundwater, in one large and many small aquifers. The aquifer is in a state of dynamic equilibrium - swelling and shrinking in response to variations in the amount of precipitation and, to a lesser extent, changes in extraction of water for consumption. Provided we don't pollute the main aquifer, supplies of clean groundwater are more than adequate to meet present and future needs, and withdrawals from the aquifer have little significant ecological impacts. That's the good news.
Wastewater. However, as we've all heard, the wastewater story is not such a happy one. Although wastewater from about 1,200 Vineyard properties receives advanced treatment in one of the Island's five wastewater treatment plants (Edgartown, Oak Bluffs, Tisbury, Airport, and Wampanoag Tribal Housing), the wastewater from more than 90 percent of Vineyard properties is handled on site - in cesspools, in older septic systems, or in newer Title 5 septic systems. Though these systems are generally adequate to deal with bacteria, 80 percent of the nitrogen we flush down our toilets ends up going right into the environment.
Wastewater is the largest locally controlled source of nitrogen pollution to our groundwater and surface waters. Coastal salt ponds are more sensitive to nitrogen than humans are, so we need additional measures to limit nitrogen release beyond Title 5. When the groundwater in a watershed - the land area where water flows into a pond - supplies large amounts of nitrogen to a pond, microscopic plants in the water (phytoplankton) increase dramatically, causing the water to become cloudy and, in extreme cases, green or brown. Also, various types of algae grow excessively. This can lead to the decline of eelgrass, which provides habitat for fish and shellfish. In the last decade, eelgrass beds have nearly disappeared from Edgartown Great Pond and Sengekontacket Pond and have decreased by more than 50 percent in Tashmoo and Lagoon Ponds. Shellfish catches have declined, causing concern for both the recreational and commercial shellfishermen.
Unfortunately, we have little control over one serious source of nitrogen pollution to our coastal ponds - acid rain (from gases produced when fossil fuels are burned by automobiles, power plants, and industries, often hundreds of miles to our west). After wastewater, the second most significant source of nitrogen pollution that we can control is fertilizers used in farming and landscaping. Water quality is also affected by water circulation and pond management. The periodic breaching of the great ponds brings clean ocean water to flush nitrogen and other pollutants from the pond, or at least dilute them.
Storm water drives silt, organic matter, bacteria, nutrients, metals and petroleum products into fresh and marine waters. The bacteria carried to our coastal ponds contribute to shellfish bed closures that impact our way of life.
The first step is for the towns and MVC to map the most problematic existing discharges into wellheads, wetlands, streams, ponds, harbors, and the ocean. A priority is road runoff contributing to shellfish bed closures or other clear impacts to natural resources.
Then, we should outline the most effective storm water pollution remediation projects for each situation. The volume of direct runoff to surface waters from current storm water collection discharges in Tisbury, Oak Bluffs, Edgartown and Menemsha can be reduced by infiltrating up-gradient segments to the ground. Programmed maintenance is necessary to keep storm water facilities effective.
Storm water management on private property can be improved through education, incentives, and regulations aimed at maximizing retention and infiltration of storm water on the property where it is generated. Such management also benefits the groundwater supply by maximizing recharge.
Since the watersheds of most coastal ponds straddle town boundaries, we need to find a way to reduce nitrogen in a watershed-wide or an Island-wide way. The Island Plan Water Resources Work Group emphasizes the importance of looking at "the big picture" when implementing watershed and storm water management programs. The work group recommends implementing regulations beyond current capability and the creation of effective management programs by amending zoning and utilizing the Martha's Vineyard Commission Act.
The work group recommends a drive to raise public awareness and understanding about watersheds, which includes educating people about the consequences that many of their day-to-day behaviors can have on the health of a watershed.
The replacement of native Vineyard vegetation with large, high-maintenance lawns or exotic vegetation reduces habitat, increases the need for fertilizers and pesticides that pollute our water supply, and erodes the Vineyard's character. Some efforts have already been made to inform the public about landscaping the Vineyard way. A broader information campaign would help counter the effects of inappropriate landscaping techniques promoted by television advertising and by people moving here with off-Island perspectives for Vineyard landscapes.
The Island Plan Water Resources Work Group proposes to encourage a comprehensive approach to water resources management to address wastewater, storm water, and water supplies in an integrated way, rather than independently. The above and other draft proposals are outlined in more detail in a discussion paper. The work group invites public comment about these proposals as well as other suggestions.
This article was written by Bret Stearns, chairman of the Island Plan Water Resources Work Group, and Bill Wilcox, MVC water resources planner. The Island Plan Water Resources Forum will be held on Wednesday, July 25, at 7:30 pm at the Old Whaling Church (Baylies Room). The Island Plan Water Resources Discussion Paper is available at www.islandplan.org.