Pam Parker, Maine DEP
Municipal Guide To Clean Water: Conducting Sanitary Surveys to Improve Coastal Water Quality
What to look for: 4. Offshore activities
Up to this point, this guide has focused on land-based sources of bacteria pollution, looking inland from the shoreline into the watershed. But activities occurring offshore can also influence water quality. The extent of the impact typically depends on the type of activity, proximity to shoreline, tidal stage, prevailing winds, local circula- tion patterns, and other factors.
Is the area used by recreational and commercial boats?
Note the location of marinas, mooring fields, anchorages, boat ramps, etc. and the presence of pump-out facilities and other waste disposal options.
The DMR conducts evaluations (typically every one to three years) of marinas impacting shellfish growing areas and defines a “marina” as an area with 10 or more boats containing MSDs. Contact DMR for evaluations of mari- nas having an effect on shellfish harvesting. Additionally, the DEP requires adequate pump-out facilities at harbors with 18 or more slips/moorings for boats greater than 24 feet in length.
Poor waste disposal practices among boaters can lead to unacceptably high bacteria concentrations. It is illegal to dump untreated sewage overboard within three miles of the shoreline. It is also illegal to dump any sewage, treated or not, into areas classified as a “No Discharge Zone.” Fecal matter and other solid waste must be disposed of with a properly functioning, Coast Guard- approved marine sanitation device (MSD). Marinas and other high-use areas should have easily accessible pump- out facilities; however, illicit dumping can still occur in areas with adequate facilities.
Determine the distance of the marina or mooring field from the beach. Monitor bacteria levels in and around marinas and other high-use areas to determine if high bacteria levels are linked to the “peak” boating season. For example, if boats are moored or anchored offshore of a beach area, are surf zone bacteria levels higher during the peak season and/or during an incoming or flooding tide stage? Consider local circulation patterns and the potential for boating waste to be transported to the shoreline.