The Four Vulnerable Areas
The Four Vulnerable Areas are the areas that the Clean Water Act mandates the Source Protection Committee to collect scientific data about. This data will then be published in the Assessment Report. The committee will then use that data to make policies around how to reduce the threat level of the significant threats identified in those areas (as well as make policies to ensure no future significant threats appear)
Wellhead Protection Area (WHPA) - map 1:
The surface and subsurface area surrounding a water well or well field that supplies a municipal residential system or other designated system through which contaminants are reasonably likely to move so as to eventually reach the water well or wells.
Wells draw water from underground areas called aquifers where water fills cracks in bedrock or spaces between grains of sand, gravel or soil. Aquifers are replenished when water from rain and melting snow soaks into the ground. sometimes, the water also carries pollutants. It can take years, or even decades, for water to reach a well. The speed depends on the characteristics of the soil and bedrock in the area.
Intake Protection Zone (IPZ) - map 2:
The contiguous area of land and water immediately surrounding a surface water intake, it is based on both distance from the intake as well as on the minimum response time for the water treatment plant operator to respond to adverse conditions or an emergency and the remaining watershed area upstream of the minimum travel time area.
River and lake intakes can be contaminated when dangerous materials are spilled into the water or on nearby land. Intake Protection Zones (IPZ) are areas where dangerous materials may get to an intake so quickly, the operators of the municipal water treatment plant may not have enough time to shut down the intake before the pollutant reaches it.
Significant Groundwater Recharge Area (SGRA):
Areas on the general landscape which recharge aquifers to a more significant degree than other areas.
Highly Vulnerable Area (HVA):
Areas on the general landscape with underlying aquifers on which external sources have or are likely to have a significant adverse effect, and includes the land above the aquifer.