Glenn County Water/Groundwater Update - August 21, 2007

There is a workshop scheduled for 1:30 pm on September 18, 2007 at the regular meeting of the Glenn County Board of Supervisors. Items to be discussed relate to the findings and recommendations of the work recently completed by the firm of Wood Rodgers, Inc. hired to assist the County in the facilitation of groundwater and coordinated water management. A final report addressing the tasks assigned in this agreement is available to be viewed at the Water Advisory Committee website, AB 303 Grant Update. Other water related items of importance to the county may also be discussed at the workshop.


The Technical Advisory Committee (TAC) to the Water Advisory Committee (WAC) has recommended interim summertime Basin Management Objectives (BMO’s) for groundwater levels in various groundwater management Sub-areas throughout the County. The WAC has accepted the recommendations of the TAC to change the location and frequency for groundwater level monitoring in accordance with Chapters 20.03.060 and 20.03.070 of Ordinance 1115, The Glenn County Groundwater Management Plan. The interim BMO’s were approved by the Board of Supervisors at their July 10, 2007 meeting. Groundwater levels were measured by the Department of Water Resources, Northern District (DWR) or staff from the Glenn County Department of Agriculture in distinct aquifer zones from the network of dedicated (observation) monitoring wells during the peak irrigation use in early August. See BMO Monitoring at

Results of the summertime measurements range from .4 feet to 7.5 feet below the stage one interim levels in the Artois area, and average 3.8 feet below the stage one interim levels in the north and eastern portion of the valley floor in the county. Because these are interim BMO’s, there will be no enforcement action associated with measurements below the established stage one alert, but it may serve as a precursor to adaptive management if necessary.

At this time, the method developed for interim summertime BMO’s is not intended to replace any previously developed method established for BMO evaluation in any Sub-area of the county. As additional data is collected, the same dedicated wells may be utilized for BMO compliance in the spring, which is the time of year most of the BMO’s are evaluated and possibly replace the current network of domestic, municipal, and agricultural wells.

The BMO method for safe yield of groundwater was initially adopted by the Board of Supervisors in June 2001. At that time most Sub-areas of the County utilized spring or fall measurements for BMO compliance from a series of domestic, municipal, and agricultural wells with the minimum of a 20 year history. With the installation of dedicated monitoring wells throughout the County, the ability now exists to establish BMO’s from observation wells under no direct pumping pressure. By utilizing dedicated monitoring wells, summertime BMO’s for groundwater level can be established to gather reliable scientific data during the peak irrigation season when possible depressions caused by pumping can be observed and evaluated. In the future, other dedicated wells with a minimum of three years of data will be evaluated for additional summertime BMO’s.

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 wa