Citizen group discusses Tisbury water

By Aubrey Gibavic - October 26, 2006

At the Tisbury Waterways (TWI) monthly meeting last Tuesday, attendants were asked to fill out a questionnaire before the meeting, and the same one directly following the meeting, to see what they learned. The test was given not by a teacher, but Wendy Culbert, an ecologist and a member of the Vineyard Conservation Society. She was attempting to find out what people knew about five terms - groundwater, aquifer, watershed, nitrogen loading, and denitrifying.

The five terms were the bases of her presentation, which outlined the threat of pollution that Tisbury's many waterways are facing, and what residents can due to curb future deterioration. "The topic of sustainability has really arrived on Martha's Vineyard," she said, noting that bodies of water on the Cape and Islands are particularly threatened because of the constantly growing population.

Ms. Culbert presented a detailed power point presentation that used colorful illustrations to show how human waste and a general lack of knowledge on the subject contributes to the pollution of Tisbury's waterways. Some of the biggest threats to the waters of Martha's Vineyard are nitrogen, phosphorus, and runoff from the roadways, she said.

A different kind of map

Eliciting the most critical examination and spirited conversation of the meeting Tuesday was a unique map created by the Martha's Vineyard Commission. At first glance it looked like the well-known outline of Martha's Vineyard, but upon further examination it was clear the traditional town lines were greatly skewed. They were, in fact, not borders belonging to the six individual towns, Ms. Culbert explained, but rather borders of the various Island watersheds.

A watershed is a section of land where all the water let into that ground space will drain into a particular body of water. There are 16 major watersheds on the Island, not including Vineyard and Nantucket Sounds and the Atlantic Ocean. Chilmark and West Tisbury share the largest watershed, approximately 11,000 acres in area, which drains into Tisbury Great Pond.

The watershed boundaries cut across town borders. The point of the map, Ms. Culbert said, was to show that someone in West Tisbury is affecting the water in Tisbury. "It's a different way of looking at the Island and really understanding the connection between the land and the water," she said. "Groundwater knows no town boundaries."

Groundwater moves very slowly. Water entering the ground in West Tisbury could take up to 30 years to arrive at Lagoon Pond, according to Ms. Culbert, while water entering the ground near the Lagoon may only take a few months.

The "Island Blue Pages, A guide to Protecting Martha's Vineyard Waters" is packed with information on the waters around and under us. It also offers encourages Islanders to help protect this precious resource. "Changing your behavior is tough," it warns. "Start slowly; begin by incorporating three new actions into your daily life. Don't expect miracles overnight, but do expect miraculous change over time."

Insulating your home's hot water heater, scrubbing boats with a brush instead of soap, disposing of hazardous waste during the special collection days and eliminating the use of toxic fertilizers, are some small changes Islanders can make to be "water-wise."

"Try to cultivate a natural Vineyard lawn," Ms. Culbert said, urging people to stay away from the lure of magnificently green, golf course yards.

The big three

Nitrogen, phosphorus, and road runoff are the three major contributors to water pollution, Ms. Culbert said. Nitrogen, which comes from wastewater, acid rain, certain fertilizers and farms, seeps into the groundwater, runs down its watershed path, and deposits itself into various bodies of water. An abundance of nitrogen in the water will exacerbate the growth of algae, which can suffocate the natural aquatic life.

According to the Blue Pages - which advises to "fertilize your pond with nitrogen only if you like it green" - wastewater is the source of more than half the nitrogen input for most coastal ponds.

Even though septic systems take out about a third of the nitrogen present in urine, the wastewater is still highly concentrated with various nutrients, which make their way into the Island's ponds and surrounding salt water.

Dissimilar to nitrogen, phosphorus is the growing force behind freshwater plants. Phosphorus comes from wastewater, acid rain, street runoff and the erosion of soil, according to Ms. Culbert. Although the nutrient has been removed from laundry detergents, it is still found in most dishwasher detergents, according to the Blue Pages.

After heavy rains, water flows downward and as it runs over impervious surfaces, collects various nutrients, gas and animal waste.

Tips for handling street runoff listed in the Blue Pages include diverting rain onto your lawn for more gradual absorption, refrain from throwing old Christmas trees or other bushes into your backyard, as this will smother the natural vegetation that holds the soil in place, and using pervious surfaces for your driveway and patio.

The driving force

TWI is a non-profit organization started in 1988 by a group of Tisbury residents who were concerned with the quality of the town's water resources. The group took water samples from Vineyard Haven harbor, Lake Tashmoo, and Lagoon Pond throughout that first summer, and installed pump-out stations for visiting boaters. There are currently pump-out boats in those areas, which pump out roughly 10,000 gallons of waste from May to October.

The non-profit group steadily increased their membership and started to collect donations, which allowed them to initiate more projects related to protecting Tisbury's water resources. In 1989 they started a program to warn the public when areas were unsafe for swimming. The Tisbury Board of Health took over the program in 1995.

In 1993, TWI won a grant to install a limestone catchment basin along West Spring Street for road run-off, and partnered with the town to complete the project.

TWI has initiated a myriad of other programs such as the Adopt-A-Beach Program where groups "adopt" a stretch of coastline to keep clean and litter-free. TWI also donated bag dispensers to the town for dog-owners to use to clean up their pet's waste. Currently, there are dispensers in Owen Park, Owen Little Way, Lake Street, Eastville Beach, and Herring Creek Road.

In 2004 they joined the Martha's Vineyard Water Alliance, a coalition of Island organizations dedicated to improving the quality of water on Martha's Vineyard

Melinda Loberg, the president of TWI, said Tuesday that the group is continuing to raise money and fund various projects. "We will continue to use water testing as the basis for everything we do," Ms. Loberg said.

Tisbury Department of Public Works director Fred LaPiana said at the meeting that he has been working with TWI for many years, and the town plans to partner with them on more projects in the future.