Ground-water Management Issues

In its 1992 Willamette Basin Report, the Oregon Water Resources Department (OWRD) identified four major ground-water management issues in the Willamette Basin:
  1. managing ground-water/surface-water connections,
  2. controlling long-term ground-water declines,
  3. managing development of low-yield aquifers, and
  4. identify areas prone to natural ground-water quality problems.

Ground-Water/Surface-Water Connections

The connection between ground water and surface water has been recognized by scientists for centuries. Because there is a general lack of specific information on the nature of this connection, ground water and surface water are often managed separately. Increasing demands on the ground-water resource, and the recognition that streamflows are at or near critical levels in some places, necessitates the coordinated management of ground water and surface water. The need for this type of management is particularly acute in areas where the law requires streamflows be kept above specified minimum levels. Demands on the ground-water resource generally are highest during times of the year when streamflow is at its lowest. The Willamette Basin Report lists several streams that appear to be effected by ground-water pumping, and the overall effect of ground-water development on surface-water resources is of concern basin wide.

The policy stated in the Willamette Basin Report is to "minimize impairment of surface-water uses resulting from hydraulic connection between ground water and surface water." Except where wells are very close to streams or producing water from channel deposits directly connected to streams, there is currently no satisfactory way to evaluate the effects of ground-water pumping on streamflow. This is particularly true for evaluating the cumulative effects of many wells. A sound, quantitative understanding of the ground-water hydrology, the nature of the ground-water/surface-water connection, and streamflow characteristics is necessary for coordinated management of ground- and surface-water resources. This understanding has yet to be developed in the Willamette Basin.

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Last modified: Mon Jan 29 13:26:40 1996