Contingency Plan

Development of a contingency plan is the last line of defense in protecting a community's water supply. Ideally, a community's wellhead protection management efforts will be more than adequate to protect its groundwater supplies. However, the contingency plan allows a community to rapidly respond to the actual or potential contamination of its water supply.

The objectives of a wellhead protection contingency plan are to:
  • Identify the susceptibility of each groundwater source to surface contamination
  • Identify source deficiencies that could affect the purveyor during an emergency or in the event a source becomes contaminated
  • Identify the emergency response capabilities of the purveyor and the surrounding communities
  • Identify short-term and long-term contingency actions that can be followed during an emergency or in the event a source becomes contaminated
Susceptibility Assessments
Each purveyor is required to complete a Washington State Department of Health Susceptibility Assessments for each active well. Based on these assessments, DOH determines a susceptibility rating of low, moderate, or high, with respect to the potential for contamination of the well. This rating can affect the monitoring frequency and waiver applicability for certain contaminant categories.

Source Deficiencies
The DOH requires that the total source capacity of all active wells be capable of meeting the maximum day demand of the water system. However, in wellhead protection planning, it is necessary to determine whether the maximum day demand can be satisfied by the total source capacity without the largest well (assumed to be contaminated). This analysis helps prepare a water purveyor for the scope of alternative water supplies that may need to be developed to protect against contamination of a water supply.

Emergency Response
Contingency planning for emergency situations is important to ensure that when a crisis occurs, appropriate decision-making personnel are informed of the scope and severity of the situation and that established procedures are in place for foreseeable types of emergencies. It is not possible to plan for every type of emergency that can affect a water system. However, by having appropriate contingency planning in place for foreseeable emergencies, mitigation measures can be implemented more rapidly and the impact to the system can be reduced. Components of an effective emergency response plan include an emergency call-up list for local emergency personnel and emergency response procedures for a number of different emergency situations.

Alternative Supplies Of Water
As a matter of planning priority, it is important to identify appropriate short-term and long-term sources of emergency water supply. These include the steps required for immediate provision of water for a periods of days, weeks, months, or years. The following is a list of short-term and long-term sources of water that each purveyor should consider:
  • Short-Term Water Sources
    • Bottled Water
    • Tanker Trucks
    • Water Conservation
    • Interties
  • Long-Term Water Sources
    • Groundwater Treatment
    • New Source Development
    • Water Conservation
    • Interties