Guidelines for Ground Water Under Direct Influence of Surface Water

By Federal rule, groundwater under direct influence of surface water (from here on referred to as SW) is defined as being any water that’s beneath the ground’s surface that contains a lot of macro-organisms or that has major changes in characteristics related to climate and SW conditions, such as temperature, pH, and turbidity. At the most basic level, this means that the groundwater is located close enough to SW that it runs into the groundwater. Although groundwater is generally considered free from pathogens, groundwater that is fed by SW will contain contaminants and must be monitored.

The amount of contamination can be determined using a three-step process:

* Testing to evaluate water quality and the particulates it contains.

* Daily monitoring on a long-term basis

* Follow-up water quality and particulate evaluations

If these tests show a problem, water systems that contain the contaminated groundwater must take certain corrective measures outlined by the Department of Health (DOH). These steps may include filtration, disinfecting, and the requirement that the facility be run by licensed personnel. These treatments are designed to remove viruses and other potentially-damaging pathogens from the water, reducing them to an acceptable level.

The DOH offers a number of options to water systems that have been identified as having groundwater under direct influence. The system can:

1. Modify the groundwater so that it no longer receives water from the surface water source.
2. Develop a new, approved groundwater source.
3. Install filtration systems.
4. Try to bring the existing water source into compliance.

Well water is groundwater under the direct influence of SW if the liquid is being drawn from an unconfined aquifer, is part of an enhanced recharge/infiltration project, water levels in SW increase downward flow when the well is pumped, or chemical water quality parameters are more like those of nearby SW than they are like the groundwater.

The DOH has developed very strict standards governing drinking water, because many of the diseases prevalent in the world are transmitted when it is untreated. All water sources that come from groundwater under the direct influence are scrutinized very closely to make sure that the health of the people consuming it isn't being jeopardized.