Groundwater Assessment

Environmental Assessment  > Groundwater Assessment in Washington State  > Active Studies  > Wide Hollow TMDL Groundwater Support

Wide Hollow TMDL Groundwater Support

Wide Hollow Creek originates in the uplands west of the City of Yakima and flows for about 17 miles before it enters the Yakima River near the City of Union Gap. The creek has been extensively channelized and realigned over the years to enhance area irrigation. It is currently used to supply water to adjacent fields and as a conveyance channel for water diverted south toward Yakima from the Naches and Tieton Rivers.

The creek's "aquatic-life-use category" is designated as "salmonid spawning, rearing, and migration."  However, the creek does not meet the standards for temperature, dissolved oxygen, or pH that are needed to support viable salmon populations. As such, it is on Washington State's list of impaired waters and is the subject of a water-quality-improvement project. To understand the impairment cause(s), Ecology conducted biological and habitat assessments of the creek and area water-quality conditions between July 2013 and June 2014.

The information assembled during the evaluations is being used to develop and calibrate a numerical water-quality model. The calibrated model will be used to examine water-quality limitations in the creek and to evaluate what temperature, dissolved oxygen, and pH levels are potentially attainable. This study, which is part of Ecology's larger water-cleanup effort for the creek, will evaluate the thermal and water-quality influences that discharging groundwater imparts to gaining reaches of the creek. See the study project plan for additional details.

Environmental Information Management database Study ID: JICA0002

Water Quality Improvement Project Middle Yakima River Area: Temperature describes one aspect of this TMDL water-quality-improvement project.

Quality Assurance Project Plan

Wide Hollow Creek Water Quality Study for Aquatic Life Use Water Quality Study Design (Quality Assurance Project Plan) describes the study in detail.

For more information, contact:

Kirk Sinclair, kirk.sinclair@ecy.wa.gov, (360) 407-6557