Groundwater study commissioned by NAWCWD says Indian Wells Valley basin condition even more critical
Naval Air Warfare Center Weapons Division recently commissioned a study by the Desert Research Institute to evaluate and update groundwater models for the IWV groundwater basin. The study is called “Groundwater Resource Sustainability: Modeling Evaluation of the Naval Air Weapons Station, China Lake, California,” and can be found on the County of Kern’s website.
According to the report, the purpose of the study was to provide an updated and improved groundwater model of IWV to help agencies as they continue making water management decisions. The study primarily focused on the usual suspects in water management, including excessive drawing from the wells, decreasing water quality, and falling ground levels above wells.
The 227 page document pulls data from the past 100 years of study on the IWV basin, then evaluates which data can most reliably be used by water management agencies moving forward. The document also provides updates on the current state of the basin and its wells.
As a tenant of NAWS China Lake, NAWCWD commissioned the study, so it mainly focuses on China Lake’s future water sustainability. However, it does also shed light on the surrounding areas as well.
For example, the study offers a more precise rate of how quickly the IWV basin recharges its water supply. Researchers measure groundwater basin recharge in a rate of acre-feet per year, where the volume of water is an acre in area and one foot in depth.
The study reports that the IWV basin recharges at a slower rate than previously believed. A 2010 report by Epstein et al estimated a recharge rate of 9,265 a.f.y., but this Desert Research Institute’s recent study shows the best estimated recharge rate to be at 7,700 a.f.y., 27 percent lower than previously believed. The study also states that current groundwater use is 3 to 4 times higher than the estimated recharge rate.
To find its data, the study pulled from 100 years of research on the IWV basin. It also collected data on pre-development conditions of the basin. It states that the basin’s water levels remained stable because its recharge rate matched the rate at which water evaporated or flowed into neighboring basins.
This information comes in at a critical time for the IWV basin, as the IWV Water District has registered to form a Groundwater Sustainability Agency. The GSA is tasked with forming a Groundwater Sustainability Plan for the IWV basin by 2020.
Forming a sustainable water plan is already a challenging task for a desert region, but the challenge becomes even more complicated as Ridgecrest aims to continue development. According to the study, both the local alfalfa and pistachio orchards expanded recently. The pistachio crop is expected to increase agricultural water demand by about 70 percent by 2025 as its orchard reaches maturity.
Still, we’re not dried up just yet. The study states that China Lake’s wells will continue providing water for a couple hundred years, even at the current rate of overdraft. The water quality will slowly degrade, but even those effects won’t be perceptible for more than 100 years.
Most of the municipal wells used by the city are in fairly good shape as well, according to the study. However, a few municipal wells are starting to see surface water approach the top of the screen.
The well’s screen is the part of the tube with holes in it which the water is drawn in through. When the water level drops below the top of the screen, the well may begin to have problems functioning. When the water level drops below the bottom of the screen, you’ve run dry.
The study says that domestic wells, or wells used by private owners, are in the worst shape. It states that the water level is already below the top of the screen for nearly a third of domestic wells in IWV. It states that most domestic wells will start to see serious functional problems, if not running dry, within the next several decades unless those wells are deepened or replaced by deeper wells.
Ridgecrest Mayor Peggy Breeden said she was familiar with the study and that it indicates the problem will require a cooperative effort to solve. “7,700 acre feet of recharge is significantly less than what has been quoted in other studies,” she said. “It sets us on a path where we have to find ways to achieve sustainability.”
Breeden, who is the city’s representative on the IWVGA, added that the path to sustainability may well be a difficult one. “It’s going to take a lot of cooperation and work on all our our parts to find solutions,” she said.
The Daily Independent will be running a series of stories on this study in the coming weeks as it continues to explore the findings this study has on the GSA, China Lake, local agriculture, and the community as a whole. Daily Independent City Editor Jessica Weston contributed to this article.