Source Water Protection Areas Map
The following map shows the 1, 5, and 10 year time-of-travel zones for members of the Hamilton to New Baltimore Ground Water Consortium. Ten year TOTs were not delineated for Southwestern Ohio Water Company. See SWPA map below.
Delineation of Source Water Protection Areas SWPAs is the first step in developing a Source Water Protection Program (SWPP). The purpose of the source water delineation is to define the surface and subsurface areas which will contribute to a well or wellfield over a one, five, or ten year time period. SWPA’s are also referred to as time-of-travel zones (TOTs).
“The time of travel zone represents how long it would take for a particle of water to travel in groundwater towards water production wells over a 1, 5 or 10 year period based on groundwater modeling that was completed in 2009.”The Consortium delineated a one, five, and ten year TOT using a numerical groundwater flow model known as MODFLOW. The program, developed by the U.S. Geological Survey for specialized groundwater investigations, considers a variety of aquifer characteristics when determining the boundaries of the TOTs. This includes the influence of recharge from surface water and precipitation, the ability of groundwater to move through the aquifer media “hydraulic conductivity”, and the influence of groundwater production wells.