The De-watering of Our Valley and Foothills?

Four Damaging Water Transfer Plans

By Jim Brobeck

A Little History

Northern California was surprised to experience what was considered a drought during the late 80’s. Though mild in comparison to the medieval era Western droughts that lasted over 100 years, these periods inspired a round of surface water sales from Sacramento Valley Rice farms to buyers south of the Delta. To make up for the transferred river water diversions, Western Canal and Richvale Irrigation districts tapped groundwater. In 1994, water sales brokered by DWR under the so-called Drought Water Bank coincided with drastic water level drops and pump strandings in numerous Durham area wells.

Affected citizens proposed a ballot initiative that would create ordinances to regulate ground water management. Measure F would have provided regulations with enforcement teeth to protect Butte County ground water from over-use in the county. Measure G provided similar regulations but with no enforcement power. After a hard fought, well financed campaign, Measure G, the weaker of the two competing ground water management plans, beat Measure F. The Butte County Department of Water and Resource Conservation was formed and a retired DWR employee was installed to head the department.

Now there are several schemes unfolding to inject our groundwater into the state water supply. While four schemes have surfaced there are undoubtedly others unfolding behind the closed doors of water resource exploiters. But first, a quick primer on the nature of Butte County’s ground water...

Hydrogeology and the Threat of Water Sales

Most people do not realize that the Sacramento Valley is primarily a saline water aquifer system, and that fresh ground water is only found in the upper formations. Marine formations, such as the Great Valley Sequence and the Lower Princeton Submarine Valley Fill deposits are the primary saline water aquifer systems in the northern Sacramento Valley. The groundwater from these aquifer systems is highly saline and unsuitable for either domestic or agricultural use.

Four major freshwater, or nonmarine, formations exist in the northern Sacramento Valley. They are the Alluvial deposits, the Tuscan Formation—units A and B, the Tuscan Formation—unit C, and the Tehama Formation. These deposits overlie the marine, or saline, formations and are the major source of fresh groundwater to wells.

Freshwater Aquifer Systems

The Alluvial aquifer system is the uppermost ground water bearing unit, reaching from ground surface to maximum depth of about 200 feet. Many domestic wells draw water from this aquifer system.

The Upper Tuscan aquifer system is exposed on the east side of the valley along the foothills and is found at a depth of about 800 feet in the central portion of the valley. This aquifer system extends west past the Sacramento River under the surface, and underlies the Alluvial aquifer system.

The Lower Tuscan aquifer system is also exposed on the east side of the valley. In the central portion of the valley, it is found at a depth of about 1,000 feet below ground surface. It lies beneath the Upper Tuscan aquifer system beginning at the eastern foothills and extends westward past the Sacramento River approaching Interstate 5. Most of the attention from water purveyors is focused on the Lower Tuscan Aquifer.

Butte Water District Conjunctive Use/Replenishment

On Nov 1, 2005 the Butte Water District proposed to the Butte County Water Commission a plan to evacuate ground water during the first weeks of rice irrigation and to artificially recharge the evacuated aquifer. This appears to be a scenario that has environmental and legal implications as the Tuscan is converted from a naturally recharged public asset to an artificially recharged water bank. By creating a replenishment district to operate the recharge facilities the Butte Water District could legally maneuver ownership of the water in the aquifer as has been done extensively in most metropolitan areas of Southern California. 

he Butte Water District conjunctive use plans to install two production wells with the combined estimated pumping capacity of 8,000 gallons per minute (gpm).

Rice farms have historically used publicly funded surface water entitlements to irrigate their fields. This unconventional use of ground water indicates a plan by surface water districts to extend their entitlement reach into the ground water.

The Sacramento Valley Integrated Regional Water Management Plan

The Northern California Water Association represents the interests of Water Districts in the Sacramento Valley. Water Districts represent about 2% of the population and members hold entitlements to publicly funded surface water projects that divert water primarily from the Feather River and the Sacramento River.

Northern California Water Association (NCWA, norcalwater.org) is applying for a taxpayer financed planning grant to fund the planning and implementation of this effort to link surface and groundwater use.

The agencies participating in the regional planning process include about 75 water purveyors but no environmental groups, watershed groups or municipalities located on the up-gradient eastern margin of the aquifer system

While the plan explains that Cities such as Willows, Williams, Orland, and other small communities are growing, there is no mention of Chico and Oroville, both located on the upgradient portion of the Tuscan aquifer.

The NCWA plan explains that they want to improve the reliability of water supply in the Sacramento Valley. But the main thrust of the plan is to provide a strategy to export water through the Delta to southern California.

Western Canal Water District/ Palmdale Water District Water Sale

Western Canal WD, which straddles Butte and Glenn County, has given notice that they will be testing the Measure G water sales ordinance by applying for a permit to sell some of their surface water entitlement to the Palmdale Water District in Los Angeles County.

Western Canal expects to replace their marketed surface water with groundwater. The 10 year contract will allow a maximum of 15,000 acre-feet a year to be sold. The sale price is $135 an acre-foot. Western Canal pays about $3/af. Palmdale Water District wants the water to facilitate the growth of Palmdale, a sprawling suburb in the high desert northeast of Los Angeles.

Regional Integration of the Lower Tuscan Formation Using Conjunctive Water Management in the Sacramento Valley

Another project that has surfaced is the Glenn Colusa Irrigation District (GCID) plan to wed the lower Tuscan aquifer to the State Water supply.

This is a proposal for a taxpayer funded grant that will facilitate the DWR objective to incorporate our groundwater into the State Water Supply.

GCID has hired a consultant, the Natural heritage Institute (NHI) to guide them through the grant process. The NHI plan is to evaluate strategies to address the full array of risks and uncertainties that impede the full utilization of the Tuscan Formation today, especially risks to current users of the Lower Tuscan Formation groundwater system.

Surprisingly the proposal is rather frank in touching on the potential impacts to us and to the environment that has sustained humans in this area for thousands of years.

“If the aquifer was depressurized in the deeper zones of the aquifer system due to the extraction of large volumes of groundwater from deep wells, then eventually the water would come out of storage in the recharge area, thereby reducing ground water levels. This would result in an increased cost for lifting ground water in the recharge area or a reduction in ground water levels to the point where existing wells might become stranded.”

Clearly even the proponents recognize that users (including creeks and the vegetation) located on the recharge area of the down-sloping aquifer may be de-watered if the aquifer is evacuated by the irrigation districts.

The proposal lures the rest of the state into considering grabbing our ground water by stating, “The Lower Tuscan Formation, if integrated into California’s water supply system, could provide major water supply reliability benefits.”

While they recognize there are risks, they urge the state to fund their approach. The plan states:

“It will take decades before we know enough about the aquifer dynamics to devise a risk- free regime, and yet it would be foolish to require that the aquifer remain an underperforming asset in the interim.”

The proponents are proposing to begin the evacuation without investigation of the Tuscan’s recharge capacity and are willing to risk damage Four Damaging Water Transfer Plans to the eastern edge of the valley to proceed with sales of their surface water entitlements.

While recognizing the risk of impacting existing wells, the NHI proposal comes up with a ridiculous bargain:

“Fortunately, there is an approach that can permit more aggressive use of the Lower Tuscan Formation while we improve our understanding of how best to manage it. We can do that by providing current Lower Tuscan ground water users a risk-free water supply alternative in the form o f a supplemental surface water supply out of Lake Oroville amounting approximately 70,000 acre feet per year, which is the amount of water needed to replace existing ground water usage in the recharge area. This would, in effect, make existing ground water users independent from the Lower Tuscan Formation aquifer system. Because they now would be on surface water, response of the aquifer system to program recovery stresses would not be problematic and in fact would be transparent to the water users.”

This is a highly unconventional use of the term “transparent.” Response of the aquifer system to drought and overdraft would be hidden, not transparent. The substitute surface water might be made available by DWR through operating Oroville reservoir more aggressively. Given Butte County’s ongoing battle with DWR over the failed promise to turn the Oroville Reservoir into a recreational paradise, this scheme is unlikely to get much support if the public and their elected representatives stay informed about the impacts.

Dewatering streams, dropping well levels, drying out root zones for valley oaks and sycamores, accelerating the movement of toxic ground water plumes, and perpetuating the destruction of the Sacramento River Delta are the logical results of allowing the State of California to integrate our ground Aquifer map water into the state water supply. Proactive education of and advocacy by the citizens of Butte, Tehama and Plumas County are required if we are to maintain and restore our environment and robust economy in the next few years.

From the Summer 2006 issue of the Environmental News.