Aquifer Storage and Recovery

Aquifer Storage and Recovery (ASR) involves injecting water into an aquifer through wells or by surface spreading and infiltration and then pumping it out when needed. The aquifer essentially functions as a water bank. Deposits are made in times of surplus, typically during the rainy season, and withdrawals occur when available water falls short of demand.

Aquifer Storage and Recovery Rule

Background

In the 2000 session, the Washington State Legislature passed Engrossed Second Substitute House Bill 2867, which expanded the definition of "reservoir" in RCW 90.03.370 ("Reservoir permits...") to include, "any naturally occurring underground geological formation where water is collected and stored for subsequent use as part of an underground artificial storage and recovery project".

This legislation allows to Ecology to issue reservoir permits to authorize ASR projects. Previously, reservoir permits were only for surface water impoundment projects.

The rule, Chapter 173-157 WAC - Underground Artificial Storage and Recovery, establishes standards for review of ASR proposals and mitigation of any adverse impacts in the following areas:

Aquifer vulnerability and hydraulic continuity
Potential impairment of existing water rights
Geotechnical impacts and aquifer boundaries and characteristics
Chemical compatibility of surface and ground waters
Recharge and recovery treatment requirements System operation
Water rights and ownership of water stored for recovery Environmental impacts

ASR Benefits

Some recognized benefits of Aquifer Storage and Recovery are:

Substantial amounts of water can be stored deep underground. This may reduce the need to construct large and expensive surface reservoirs.
ASR systems are considered to be more environmentally friendly than surface reservoirs. They also offer more protection from tampering.
ASR may restore and expand the function of an aquifer that has experienced long-term declines in water levels due to heavy pumping necessary to meet growing urban and agricultural water needs.

ASR Application Process

In the 2002 legislative session, Engrossed House Bill 2993 simplified the application process for an ASR project by specifying that Ecology "may accept for processing a single application form covering both a proposed reservoir and a proposed secondary permit or permits for use of water from that reservoir."

Following are the basic steps involved in permitting an ASR project:

Prior to applying, assess potential issues and impacts to the hydrogeologic system and the environment. If the general setting and conditions cannot be described in sufficient detail for the application, then a more detailed feasibility study must be performed. The feasibility study should reduce uncertainty with respect to project issues and impacts, as well as better quantify the available storage within the aquifer.
Schedule a pre-application meeting with Ecology to discuss the project plan and likely requirements for monitoring and mitigation.
Submit an application for an ASR project that contains at a minimum:

Water rights for the source waters for the proposed ASR project.

A general description of the physical design of the hydrogeologic system prepared by an engineer or geologist registered in the state of Washington.

A general description of the operational design of the hydrogeologic system prepared by an engineer or geologist registered in the state of Washington.

A project plan.

A data monitoring plan.

An environmental assessment and analysis of any potential adverse conditions or potential impacts to the surrounding environment, limited to storage and subsequent use of stored water, that might result from the project.

Water Quality Issues

Water to be stored in an aquifer as part of an ASR project must meet water quality standards for ground waters of the state of Washington (Ch. 173-200 WAC). Additionally, injection wells for an ASR project must be registered with Ecology in accordance with the provisions of Chapter 90.48 RCW (Water Pollution Control Act) and Chapter 173-218 WAC (Underground Injection Control Program). For more information on the Underground Injection Control program, please see the UIC Web site.