The term "Source Water" is used to define drinking water in its original environment, either as surface water (rivers, streams, reservoirs, lakes) or as groundwater (aquifers), before being withdrawn, treated, and distributed by a water system. Source Water Protection (SWP) is the act of preventing contaminants from entering public drinking water sources.
The quality of the source water can be influenced by both natural and human activities. The concept of Source Water Protection (SWP) is to manage the areas through which water travels and the activities that occur on the land, in order to protect the quality of the resource. These protection efforts save the community money through improved water quality requiring less treatment, longer life cycle for a well, and less likelihood of having to seek an alternate source or replace the well due to contamination.
Surface water is more susceptible to contamination incidents from natural or man-made causes, such as a flood or a chemical spill, but it also recovers much more quickly than does groundwater. Groundwater is much less susceptible to contamination, but when that happens, natural recovery is very slow to occur. Source Water Protection includes both groundwater (wellhead) protection and surface water protection.
The Iowa DNR's SWP Program is a voluntary program, although there are numerous benefits for a water system to protect its water supply. There are three components to the Source Water Protection Program.
- Phase 1 Assessment: The DNR provides the initial source water assessments, called Phase 1 assessments, to all public water supplies in Iowa. This assessment details the water system's active wells, delineates the source water protection areas, lists the susceptibility to contamination classification, and provides the known potential contamination sources.
- Source Water Protection Plan: In the second step, the system then develops its SWP Plan through a local team effort. These plans are sometimes called Phase 2 plans. The components are listed in a templated plan that is used to guide the team through the process to determine how the system will protect its drinking water resource.
- Implementation: In the third step, the SWP Plan is implemented, addressing the specific items that the community and system will use to protect its drinking water resource.
The development of a good SWP Plan doesn't require any assistance or involvement of an engineer or consultant. A system may wish to contact an outside entity for assistance. The Conservation Districts of Iowa and the Iowa Rural Water Association provide experienced source water consultation and assistance for developing the SWP Plan, at no charge to the public water supply.