Tehama County

Groundwater Management

Introduction

Currently 1.2 million acre-feet of groundwater are withdrawn during an average year in Tehama, Glenn, Butte, and Colusa Counties and reliance upon groundwater in the northern Sacramento Valley is on the rise. Prior to 1970, just over 9,100 domestic and irrigation wells had been drilled in the northern Sacramento Valley. By 2006, the total number of wells increased to over 37,000 wells. In total, this represents an increase of about 28,000 wells for groundwater extraction in the past 30 years. Specifically, domestic wells increased from 6500 wells before 1970 to over 31,000 wells in 2006. Irrigation wells increased from about 2,600 wells prior to 1970 to over 6000 wells in 2006. The increase is greater in Butte, Shasta, and Tehama Counties where larger communities exist than in Glenn and Colusa Counties where the area is predominantly rural. One of the more pronounced shifts has occurred in Tehama County, where prior in the 1970's approximately one-third of the county's water supply was from groundwater and two-thirds was from surface supplies. By the 1990's two-thirds of the county's water supply was from groundwater and one-third from surface water.

The reasons for this growing dependency upon groundwater in the northern Sacramento Valley is complex and is attributed to a combination of factors rather than any single factor. Such factors include:

  • More local, regional, and statewide demand due to growth and change in land uses;
  • Need for reliable and flexible water supplies;
  • Higher costs and environmental concerns associated with new surface water conveyance and storage facilities

Tehama County Groundwater Conditions by Sub-basins

A county-wide groundwater management plan was adopted in 1996 and is still being implemented today.  Currently an update to the plan is in progress and should be in place in 2013.  This Plan is founded on voluntary cooperation of various local water interests in the County and focuses on monitoring and education to understand the groundwater resources in Tehama County.  As part of the monitoring, the valley floor of Tehama County has been divided into 12 different groundwater sub-basins based upon unique hydrology, geology, land uses, and population. Below is the first in the series.

Websites Related to Groundwater Management in the Northern Sacramento Valley

Groundwater Management

Groundwater is a resource that has been developed by thousands of individuals and community groups living in the northern Sacramento Valley and until recent years there has been little coordination among water users. So, is it realistic to believe that groundwater should be and can be managed? The question of whether groundwater should be managed is a philosophical question. Incentives for groundwater management are apparent. Sufficient groundwater must be preserved to meet future agricultural, residential, environmental, and industrial needs. The Sacramento Valley consists of fresh water aquifer systems underlain by larger saline water aquifer systems. Groundwater management must prevent mixing of the fresh and saline aquifer systems. Implementing groundwater management can also clearly demonstrate the extent that groundwater can be relied upon and the necessity for more surface water development. Whether groundwater management can be accomplished is uncertain. Political and fiscal constraints can prevent groundwater management unless a sound approach is taken.

Groundwater and Water Wells Information Series

The University of California Cooperative Extension has worked cooperatively over the past four years with the California Department of Water Resources, Northern District and the "Four County Drinking Water Quality Program - Butte, Glenn, Tehama, and Colusa Counties" to provide science-based information about the area's groundwater resources. Each article in the series is three pages with color photos and illustrations. The articles are available below:

NORTHERN SACRAMENTO GROUNDWATER NEWSLETTER SERIES
Published by the University of California Cooperative Extension, Tehama County

Funded by the Renewable Resources Extension Act
Published from April 2003 through July 2004
Six articles in this series

 

Funded by the "Four County Drinking Water Quality Program"
Glenn, Butte, Tehama, and Shasta Counties
Published by the University of California Cooperative Extension, Tehama County
Five articles in this series

Funded by the "Tehama Flood Control and Water Conservation District and the Glenn County Water Advisory Committee"
Published by the University of California Cooperative Extension, Tehama County
in October 2011