Preparing for a Sanitary Survey
MAPS AND SPATIAL INFORMATION
Maps are excellent tools for determining the general outline and characteristics of the drainage area(s), as well as for estimating the potential number of pollution sources. Maps and aerial photographs may suggest prop- erties with the greatest likelihood of affecting water quality, and therefore they can be used to prioritize areas for survey work. These are generally areas in close proximity to the shoreline, banks of rivers/streams, storm drains, land with steep sloping topography, impervious surfaces, etc. A list of potential sources may be coded and documented on a good map of the area with a useful scale.
Aerial photographs, US Geological Survey topographic maps, tax maps, and zoning maps can be gathered from the municipality and/or regional planning commission. Maps may be available in digital format using online mapping software such as Google Maps or Google Earth, Bing Maps, or Geographical Information Systems (GIS); see Appendix I for details on GIS and access to mapping data.
Communities without GIS or other mapping capabilities at the local level have several options. The water- shed can be determined fairly easily using topographic maps and aerial photographs,20 though some field work is needed to verify drainage divides that have either changed or were not accurately mapped. Town tax maps are valuable tools for identifying potential pollution sources. Finally, other entities within the state and region may have current or existing watershed-level data. The DEP or the Maine Geological Survey may have watershed maps of particular areas along the coast. Depending on the watershed, it may be delineated in an existing digital data set. Regional planning commissions, land trusts, libraries, and research institu- tions (e.g., Wells National Estuarine Research Reserve) may have watershed data available for certain areas in Maine.
factor. While all sources of fecal contamination may not be identified, targeting human sources first should result in a measurable improvement in water quality.
What information about the watershed already exists?
Depending on the location of the area of concern, infor- mation and maps needed to design a survey likely already exist. State and federal agencies, universities and research institutions, and nonprofit environmental organizations all conduct watershed investigations and assessments. Before heading to the field, find out what information is available for the area, and identify related activities. Researching any prior survey work also can identify po- tential partners who may contribute resources or exper- tise. This information will help inform the survey design,
prioritize survey areas, and improve organization, all key elements to a successful and efficient survey.
The following entities should be consulted before beginning a survey. The most current survey and water quality data should be requested directly from the appro- priate contact.
Maine Healthy Beaches (MHB) Program:
Beach water quality data (e.g., bacteria, temperature, salinity, tidal stage, rainfall, observations) for areas par- ticipating in the MHB Program can be accessed via www. mainehealthybeaches.org. Additional monitoring data for rivers, streams, and storm drains impacting beach areas with chronic bacteria issues may be available from the lo- cal “beach manager” and/or MHB Program coordinator.