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Water: Nonpoint Source Success Stories

Massachusetts: Section 319 Success Stories, Vol. III

Begin Page Links Story 1  |  Story 2  |  State Water Quality Site Exit EPA Disclaimer  End Page Links Story Separation Bar Broad Marsh River Storm Water Remediation Project:
Infiltration Structures Reduce Pollutants, Save Shellfish Beds



Contact:
Website or
Massachusetts Department of Environmental Protection
627 Main Street
Worcester, MA 01608
508-767-2792
Primary Sources of Pollution:

storm water runoff
Primary NPS Pollutants:

suspended solids

fecal coliform bacteria
Project Activities:

infiltration structures
Results:

99.99 percent removal of fecal coliform bacteria

90 percent removal of fecal streptococcus bacteria

elimination of petroleum hydrocarbons and zinc

shellfish beds reopened

Over the past decade, the Town of Wareham, Massachusetts, has begun one of the Commonwealth's most complete programs to address the pollution problems caused by storm water discharges along the town's shoreline. Contamination from storm water runoff, particularly suspended solids and fecal coliform contamination, has forced many shellfish beds and public bathing beaches along Massachusetts' coast to close. The closures can range from periodic closure for a few days after heavy rainstorms to complete year-round closure due to nonpoint source contamination. Like many coastal communities, Wareham relies on fishing and tourism for its economic vitality. Faced with the prospect of losing its unique and valuable coastal resources, the town began to search for ways to address the contamination problem.

Selecting the right alternative

In 1993 the Town of Wareham and the Buzzards Bay Project received 319 funding to remediate storm water discharges along the lower reaches of the Broad Marsh River. The goal was to reopen 64 acres of adjacent softshell clam and quahog beds. The project also intended to demonstrate that leaching catch basins could be an effective storm water remediation tool to reduce coliform contamination in the town's coastal waters.

During consultations with the U.S. Department of Agriculture's Natural Resources Conservation Service, several alternatives for treating storm water discharges were considered. The site conditions were difficult—a high ratio of impervious surface and areas of high ground water. Narrow roads, existing gas, sewer, and water lines, and groundwater close to the surface made designing the system challenging.

Because of land constraints, the final project design involved installation of "under-the road" infiltration structures along road rights-of-way. Two different types of infiltration structures were installed with the purpose of storing and treating the first ½ inch of rainfall. In areas with adequate separation from groundwater, 4-foot by 4-foot concrete leaching galleys were installed; in areas with shallower groundwater, shallower plastic infiltration chambers were installed. The infiltration structures were installed at 15 storm water discharge points along the banks of the lower Broad Marsh River. Instead of being discharged directly into the river through storm drainpipes, the storm water would be directed into infiltration structures, allowing for filtration of the pollutants.

Reopening the shellfish beds

Initial postconstruction monitoring data indicated that the infiltration systems were very effective in removing fecal coliform bacteria (99.99 percent removal) and fecal streptococcus bacteria (90 percent removal) from the storm water runoff. The infiltration systems were also quite effective in removing petroleum hydrocarbons and zinc. These pollutants were present at low levels in the storm water prior to the infiltration treatment; however, they were not detected during postconstruction monitoring.

Two and a half years after installation of the leaching catchment basins, Massachusetts Division of Marine Fisheries (DMF) announced that the shellfish beds in the Broad Marsh River would be reopened on a conditional basis. The beds continue to be temporarily closed after heavy rainfalls, but the large softshell clam and quahog resource is now open to shellfishermen most of the time.

Success inspires additional projects

Other successful 319 projects have since followed. A storm water treatment system was installed in the upper reaches of the Broad Marsh River, with the hope that over time water quality will improve to the point that the Broad Marsh River shellfish beds can be reclassified and opened without restrictions of any kind.

In addition to the continued storm water remediation work on the Broad Marsh River, town officials have set their sites on reopening the larger shellfish beds in Onset Harbor. Onset Harbor is larger and more open than the Broad Marsh River, and its watershed area is heavily developed and quite urban. The town now has two additional ongoing 319 grants that are being used to target the storm water discharges from these urbanized areas. In recent correspondence, Michael Parola, Harbormaster/Shellfish Constable for Wareham, confirmed that storm water remediation efforts have exceeded expectations. The town's current goal is to remediate "any and all active storm drains" because of their overall effect on water quality and on the town's shellfish beds. Parola believes that storm water remediation has been largely responsible for allowing the Massachusetts Division of Marine Fisheries to upgrade miles of publicly accessible shoreline. The current remediation projects in Onset Bay and its tributary, the East River, have the potential to allow the DMF to upgrade fully half of Onset Bay's shellfish beds from their current classification, seasonally closed, to open and approved for shellfish harvesting.

Like so many coastal communities that rely on fishing and tourism for their livelihood, Wareham faced the loss of the coastal resources that make the town unique and vital. Wareham has taken full advantage of the opportunity that the 319 Program presented to address nonpoint source pollution problems and restore coastal resources for all to enjoy. Given the demonstrated success of the Marsh River Project in both reopening shellfish beds and inspiring a community to institute a phased, long-term storm water management program, the Massachusetts 319 Program should encourage other communities to do the same.

Begin Page Links Story 1  |  Story 2  |  State Water Quality Site Exit EPA Disclaimer End Page Links Story Separation Bar
Lake Tashmoo Storm Water Remediation Project:
First Flush Leaching Basins More Effective Than Expected



Contact:
Jane Peirce
Massachusetts Department of Environmental Protection
627 Main Street
Worcester, MA 01608
508-767-2792 | Jane.Peirce@state.ma.us
Primary Sources of Pollution:

storm water runoff
Primary NPS Pollutants:

suspended solids

fecal coliform bacteria
Project Activities:

12 first flush leaching basins
Results:

91 percent decrease in fecal coliforms

98 percent decrease in total coliforms

elimination of oil, grease, barium, chromium, and lead

shellfish beds reopened

Contamination from storm water runoff, particularly suspended solids and fecal coliform contamination, has forced many shellfish beds and public bathing beaches along the Massachusetts coast to close. The closures can range from a few days to the summer to the entire year, depending on the type and level of contamination. The town of Tisbury on the Island of Martha's Vineyard has numerous "hotspots" where access to shellfish beds and public beaches has been restricted because of storm water contamination. The residents of Tisbury rely on fishing and tourism for their livelihood, so it is imperative for the town to find ways to effectively treat storm water contamination.

At 1 mile in length, Lake Tashmoo is one of the larger of the saltwater lakes on the island that feed into the sea. It is an ideal habitat and breeding ground for oysters, scallops, clams, mussels, crabs, lobsters, and a variety of fish species that serve as the food source for larger fish, all of which are commercially harvested as the backbone of the island's fishing industry. In addition, the lake has a major beach area, a town dock, and boat moorings and is used for swimming, sailing, wind surfing, boating, and sportsfishing.

Before 1994 hard shell clam, mussel, and scallop beds near the storm water outlet were showing contamination from fecal coliform bacteria, heavy metals, and oil and grease. The Division of Marine Fisheries routinely closed the beds after large rainfall events because of fecal coliform levels in the water. The contaminant levels were consistently high enough that the shellfish beds were on the verge of seasonal closure, which would have effectively put the resource off-limits to the local townspeople and to the large seasonal population that flocks to Martha's Vineyard during the summer months. Recreational use of the lake is a major tourist attraction, and the town considered maintaining the lake in a viable and usable state imperative.

Adding leaching basins

In 1994 Tisbury Waterways, Inc., and the Town of Tisbury received 319 funding to install a series of 12 "first flush" leaching basins along road drains to capture and treat the road runoff that was contributing to the contamination of highly productive shellfish beds at one end of Lake Tashmoo. The first flush basins, installed along a 1.6-mile stretch of road, were designed to treat the first ¼ inch of rainfall, which contains most of the contaminants.

Each basin consists of a 6-foot by 6-foot perforated cement vessel filled with limestone, surrounded by a gravel bed. The limestone in the basins is covered with hydrophobic, oil-absorbing pads, which help to separate the hydrocarbons from the runoff. The limestone in the pits raises the pH of the runoff, causing heavy metals to precipitate and accumulate in the pit. Finally, the first flush basins provide additional residence time for fecal coliform bacteria to oxidize and decay. The treated runoff then passes through the gravel surrounding the pits into the subsurface soil.

Exceeding expectations

Comparison of contaminant concentrations in Lake Tashmoo before and after installation of the basins showed significant improvement in water quality. Samples from Lake Tashmoo during rainfall events showed fecal coliform and total coliform levels going down by 91 percent and 98 percent. Oil and grease could not be detected in the treated effluent; barium, chromium, and lead, which had all been present before installing the basins, could no longer be detected in the effluent. The project was deemed a success and recommended as a model for other storm water hotspots around Tisbury.

The system is exceeding the town's initial expectations. Although it was designed to capture and treat the first ¼ inch of storm water runoff, the system appears to be capturing and treating the first ½ inch of runoff. The sandy soils that underlie the leaching catch basins allow the treated storm water to percolate into the ground more quickly than the designers anticipated, thus allowing the system to capture additional storm water.

As a result, since the basins were installed there has been no discharge at all to Lake Tashmoo during moderate rains. Even during heavy rainfall, less storm water is discharged into the lake and the water continues to be of significantly better quality than before the basins were added. The Massachusetts Division of Marine Fisheries has continued to monitor water quality at the shellfish beds. The beds have not been closed during the past several years, and there is no longer any thought of seasonal bed closure.

Story 1  |  Story 2  |  State Water Quality Site Exit EPA Disclaimer


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