DNR wells and water level monitoring

Air line measurement at DNR well.

Air line measurement at DNR well. Photo: DNR

The Washington State Department of Natural Resources (DNR) relies on more than 80 wells for water supply to irrigate crops under agriculture leases. On most leases with existing well(s), the well(s) provide the primary source of water for irrigation under the lease. In other cases, the well(s) serves as a backup supply to a surface water source. In either case, the wells and associated water rights are valuable assets to the State. As stewards of these water rights and wells, DNR is responsible for effectively managing them to produce revenue for public schools and other state trust land beneficiaries.

DNR water-level monitoring data provide important information about the aquifers the department use for irrigation water. Identifying and tracking the presence and magnitude of water-level trends, including declines, can help us anticipate well and pump issues. The monitoring information helps us assess the lifespan of an existing well or the need for future well repairs or maintenance. The monitoring data also are critical to DNR’s long-term planning and decision-making for future water supplies on irrigated agriculture leases.

DNR has regularly measured water levels in about half of its wells, with data sets in many cases extending back to the time that the wells were drilled. DNR typically measures water levels in the early spring in order to track trends in water levels prior to irrigation season pumping. Currently, DNR is expanding its monitoring network to track water level trends at wells completed in the different aquifers on which the department relies for irrigation.

Many DNR wells are relatively deep wells into the Columbia River basalts. In most cases, DNR uses air line measurements to track water levels in these wells. This requires the installation and maintenance of air lines at each DNR well, regardless of whether they are part of the current annual water level monitoring network or are only measured periodically. An important part of the monitoring effort is to work closely with lessees to ensure that functional air lines with known depth settings are put in place when pump work is done, and when pumps are pulled.

DNR is working to broaden its monitoring network and track the data spatially in a geographic information system (GIS) so that well information can be easily accessed and used. In addition, DNR looks to other publicly available water level data for wells in the vicinity of state trust lands. In this way, we can continue to plan for the future on our agriculture leases.

By Ingrid Ekstrom, Hydrologist, DNR Product Sales & Leasing Division