Ground Water Management Area

The Columbia Basin Ground Water Management Area, or GWMA is a pro-active, local planning effort for the reduction of nitrate concentrations in the ground water, and is intended to lessen the need for mandated control measures through a cooperative effort between local citizens and government through the creation of a GWMA plan to reduce nitrate levels in the Columbia Basin. The partners of the GWMA believe that the planned implementation of best management practices (BMP's) will lead toward improving trends in the groundwater nitrate levels of the Columbia Basin.

The Columbia Basin GWMA is consisted of Grant, Adams, Franklin and Lincoln Counties. Together, the four counties in the Groundwater Management Area make up approximately 8,300 square miles.

CHARTING COLUMBIA BASIN AQUIFERS

3-Dimensional Geologic Block Diagram Near Moses Lake, WA

Deep beneath the wind-swept plains of eastern Washington lies an aquifer system that extends over an area of 6,000 square miles and to a depth of over 1,000 feet. It is the source of groundwater, which is critical because it supplies over 80% of the drinking water used in eastern Washington. It is vital that the Columbia Basin Ground Water Management Area (GWMA) - a group of area stakeholders dedicated to developing sound solutions to protect the groundwater in the Columbia Basin - manages this groundwater supply wisely to ensure adequate future supply and economic growth.

Comprehensive Hydrostratigraphic Model

GSI Water Solutions Inc. is developing a comprehensive hydrostratigraphic model for GWMA that defines the layers of water bearing rock and the pathways through which groundwater flows. The study team is tracking data on geologic and hydrogeologic conditions in the primary aquifers and examined over 10,000 well logs. The Franklin Conservation District is working with GSI to model the 3-dimensional geologic framework of the region's aquifers showing the lateral and vertical extent of the major basalt and sediment water-bearing layers. From this comprehensive research and modeling, they are developing a flexible database and integrating it into GWMA's existing database where GWMA can refine and expand it to suit future needs.

A Foundation for Future Water Supply Planning

The comprehensive hydrostratigraphic model provides the technical foundation needed for the region's future water supply planning. It is a valuable tool that scientists and stakeholders can use to refine the system of wells that GWMA monitors and to define controls on groundwater flow, recharge, and discharge into the aquifer system. The hydrostratigraphic model can predict where potential aquifers are located, determine the link between aquifers and surface water, find areas that recharge to aquifers, and be used to locate wells. It can also improve placement and selection of BMP's to reduce nitrates in groundwater, a subject of deep concern to this farming area.

Valuable Planning Tool

The maps provided by the Hydrostratigraphic Project can provide a 3-D visualization of the geology underlying any location in the GWMA.

For more information about GWMA contact:

Paul Stoker, Executive Director
Columbia Basin Ground Water Management Area
449 E. Cedar Blvd.
Othello, WA 99344
509-488-3409