Glenn County Groundwater Update - April 10, 2007

The semi-annual spring groundwater level measurements for Glenn County made by the California Department of Water Resources, Northern District (DWR) were completed during the week of March 26-30, 2007. Spring measurements are the basis for Basin Management Objectives (BMO) established to determine groundwater safe yield of many groundwater management sub-areas of the County. The results of these measurements were presented at the April 10th meeting of the Glenn County Water Advisory Committee.

At the time of measurement, 16 wells throughout the County that utilize spring measurements for BMO compliance were below average for this time of year. Subsequent measurements of a few wells in the Orland area indicates groundwater levels are rising, due to additional releases of water to Stony Creek from Black Butte Reservoir and from local irrigation .

Clearly, these low groundwater levels are the result of insufficient rainfall during the winter and spring months, accentuated by the need for early irrigation to permanent crop plantings throughout the County. To date, there have only been between 7 and 8 inches of rainfall recorded for the season, less than half the annual average (July 1, 2006 – June 30, 2007). Precipitation and surface application of irrigation water are the primary sources of recharge in our area to meet the needs of the majority of wells used for irrigation; other potential sources of recharge are currently being studied. As the irrigation season progresses, some groundwater levels may increase and some will decrease further, which may cause some difficulty during the peak irrigation season.

BMO’s for groundwater levels were established and adopted by the Board of Supervisors in June, 2001. Currently, all of the wells utilized for BMO compliance are for domestic or agricultural use. Over the years, there have been many dedicated monitoring wells installed by the County and Water Advisory Committee (WAC) member irrigation districts to monitor groundwater levels and quality. The intent of the monitoring wells is to develop a monitoring network independent from these production wells. The WAC is in the process of incorporating these wells towards the development of Countywide BMO’s. To date, there is only one dedicated monitoring zone observed for this purpose. By the summer as many as 12 more zones will be added on an interim basis.

Glenn County is not alone this year with lower than average groundwater levels. Similar situations exist in Butte, Tehama, and Colusa Counties. Current and historic groundwater levels in our region can be viewed on DWR’s Water Data Library. Their web page is: http://wdl.water.ca.gov/gw/map Point to Glenn County and navigate regionally from there.

If you feel you are experiencing pumping problems that may be due to low groundwater levels, there is a process for documenting this by filing a report of abnormal groundwater level with the Glenn County Department of Agriculture. These report forms are available at 720 N. Colusa Street, Willows or just call (530) 934-6501 and a form will be sent to you. Any information that can be gathered is helpful to ensure an adequate supply of water for domestic, municipal, industrial, agricultural, recreational, and environmental use.