Lake Sampling Site Location

**For the Mass. Department of Environmental Protection-approved SOP, get the pdf file here

Locating a permanent sampling site on your lake is very important so that you or other monitors can consistently find the site. MassWWP suggests choosing the deepest spot in the lake if only sampling one site.

Equipment List

  • Bathymetric or other map of the lake (DER has some bathymetric maps available at this site
  • Site location sheet and pencil


Using a bathymetric map, go to your chosen site.

With the boat securely anchored at the site, select two permanent landmarks on shore that align one behind the other. This alignment forms an imaginary line through the objects to the site in a manner analogous to siting a gun. (See image below.)

At about a 90 degree angle to this first bearing or line, select two more aligning landmarks.

All four landmarks and your sampling site should be carefully marked on your map of the lake.

Describe each landmark so that others can easily locate it. Remember that the "white house with green shutters" may be a brown house with black shutters next year, so try to find descriptive characteristics that are not likely to change, e.g. two-story brick house with wrap-around porch and two-car garage on north side. Mark your sites on a field map. Include site code (e.g. #1, Deep Spot, etc.).

lake map image

Image from EPA's Volunteer Lake Monitoring: A Methods Manual