What is a CGWA and GWMA?

The authority for designating areas for regulating ground water withdrawals from aquifers subject to insufficient supplies was first granted in 1953 through amendments to Idaho’s Ground Water Act. However, it was not until 1962 that the first CGWAs were designated in the Oakley Fan area. Amendments to the Act in 1982 granted authority for designating ground water management areas. The Grandview-Bruneau area, designated in 1982, was the first GWMA.

The Director of Idaho Department of Water Resources (IDWR) is granted the authority to designate "critical ground water areas" and "ground water management areas" under Idaho Code Title 42, Chapter 233a and 233b, respectively. These sections codify the definitions and bases for designating these special management areas.

A CGMA is all or part of a ground water basin that does not have sufficient ground water to provide a reasonably safe supply for irrigation or other uses at the current or projected rates of withdrawal. The Director of IDWR can deny an application for a proposed use if the point of diversion lies within the designated area and may require water users to report diversions or other information.

A GWMA is all or part of a ground water basin that may be approaching the conditions of a CGMA. Applications for new water appropriations may be approved only after it is determined that sufficient supply is available and other prior water rights will not be injured. The director may require reporting of water use by water users within the area.

The Order designating the Southeast Boise GWMA in 1994 was the first time an advisory committee was required as a part of the initial formation of a GWMA. Since that time, orders requiring the formation of advisory committees have been issued subsequent to the initial formation of the management areas. These committees are to assist in the management of ground water resources through development of management plans, establishing processes for dispute resolution and acting as a forum for discussion and communication.