Water Testing

Water testing has always been at the forefront of TWI’s mission to safeguard our waters. Test results have pointed the way to all of TWI’s projects in wastewater and stormwater management.

What initially galvanized our founding members was a whiff   of rotting Japanese seaweed from Vineyard Haven harbor. First we learned that dredging the channel through the southwestern inlet would increase  circulation in the harbor and greatly reduce this offensive stench.

While working on dredging permits and required engineering, we looked beyond the harbor’s current problem to investigate a potentially more serious condition: Was the harbor safe for swimming and shellfishing? Thus began our critical program of water testing – which would eventually include the Lagoon and Lake Tashmoo –  and delivering water samples to the Board of Health to help them fulfill its State mandated obligation to safeguard swimming areas. We also involved the Department of Public Works (DPW) and  partnered with them to expedite mitigation measures for storm water run-off, a major cause of water pollution.

Over the last 20 years, TWI has kept records of water sampling at 8 locations around our three bodies of water to determine the need for the installation of first flush basins and vegetative bioswales to filter stormwater runoff. We are constantly evaluating potential trouble spots and adding new stormwater collection sites.

To facilitate TWI’s repeated testing of storm water run-off, we are partnering with The Tisbury Department of Public Works, helping them to establish a water testing laboratory that will test for pollution from Total Coliform, Escherichia coli, and Enterococcus bacteria.  These three bacterial tests are the most appropriate measures of the health risks due to bacterial contamination of the water.  There ate two ways that this laboratory will improve our testing program; we will be able to (1) sample the water on any day of the week and (2) get the results of the water tests the day the tests are completed.  The latter is especially important to identify problems and facilitate remediation actions.

The laboratory will be certified by the State to test for bacterial contamination in both fresh and salt water.  This certification ensures that the most appropriate testing procedures are used and that the test results will be valid in court (in the unlikely event that that is necessary).