Tulare Lake

Time Limits for Western Water Rights

Natural Resources and Environment (SSRN) | November 1st, 2022

Time-varying land subsidence detected by radar altimetry: California, Taiwan and north China

Nature Portfolio (Springer Nature) | June 21st, 2016

Contemporary applications of radar altimetry include sea-level rise, ocean circulation, marine gravity, and icesheet elevation change. Unlike InSAR and GNSS, which are wi

Contemporary applications of radar altimetry include sea-level rise, ocean circulation, marine gravity, and icesheet elevation change. Unlike InSAR and GNSS, which are widely used to map surface deformation, altimetry is neither reliant on highly temporally-correlated ground features nor as limited by the available spatial coverage, and can provide long-term temporal subsidence monitoring capability. Here we use multi-mission radar altimetry with an approximately 23 year data-span to quantify land subsidence in cropland areas. Subsidence rates from TOPEX/POSEIDON, JASON-1, ENVISAT, and JASON-2 during 1992–2015 show time-varying trends with respect to displacement over time in California’s San Joaquin Valley and central Taiwan, possibly related to changes in land use, climatic conditions (drought) and regulatory measures affecting groundwater use. Near Hanford, California, subsidence rates reach 18 cm yr with a cumulative subsidence of 206 cm, which potentially could adversely affect operations of the planned California High-Speed Rail. The maximum subsidence rate in central Taiwan is 8 cm yr. Radar altimetry also reveals time-varying subsidence in the North China Plain consistent with the declines of groundwater storage and existing water infrastructure detected by the Gravity Recovery and Climate Experiment (GRACE) satellites, with rates reaching 20 cm yr and cumulative subsidence as much as 155 cm.

To Stop Desert Encroachment

Scientific American | November 1st, 1938

When Spanish vaqueros first entered the interior valley of California they saw only a vast expanse of desert, broken infrequently by patches of green vegetation a

When Spanish vaqueros first entered the interior valley of California they saw only a vast expanse of desert, broken infrequently by patches of green vegetation along the water courses. Little did they dream that in a span of two generations the region would become one of the world's garden spots, the home of thousands of prosperous families, and the source of millions of tons of food products known around the world. They did not envision the romance and adventure that marked the development of this great inland empire-now a two billion dollar agricultural wonderland built by irrigation and wholly dependent upon a single natural resource-water.

Total Water Management Study for the Central Valley Basin, California, Central Valley Project Intermittent Surface Water Supply, Working Document No. 6

U.S. Bureau of Reclamation (USBR) | April 1st, 1975

Total Water Management Study for the Central Valley Basin, California, Central Valley Project Water Yield Risk Working Document No. 5

U.S. Bureau of Reclamation (USBR) | February 1st, 1975

Total Water Management Study for the Central Valley Basin, California, Interim Water Supply Working Document No. 9

U.S. Bureau of Reclamation (USBR) | March 1st, 1976

Towards sharing water better with near real-time maps on evaporative water use by crops and natural vegetation

Nature Portfolio (Springer Nature) | January 15th, 2024

The combination of advancements in evapotranspiration theory, eddy covariance flux measurements of water vapour and satellite remote sensing are putting technology on the

The combination of advancements in evapotranspiration theory, eddy covariance flux measurements of water vapour and satellite remote sensing are putting technology on the verge of producing information on evapotranspiration with unprecedented coverage and resolution. The OpenET project provides this information to farmers and land and water managers for better water practice.

Toxicological assessment of potable reuse and conventional drinking waters

Nature Portfolio (Springer Nature) | October 27th, 2022

Potable reuse, the process of treating wastewater to drinkable standards, offers a reliable and sustainable solution to cities and regions facing shortages of clean water

Potable reuse, the process of treating wastewater to drinkable standards, offers a reliable and sustainable solution to cities and regions facing shortages of clean water. However, implementation is hindered by perceptions of poor water quality and potential health threats. Herein, we compare water samples from potable reuse systems with conventional drinking waters based on the analysis of Chinese hamster ovary cell cytotoxicity contributed by disinfection by-products (DBPs) and sewage-derived anthropogenic contaminants. In all cases, the cytotoxicity of potable reuse waters is lower than that of drinking waters derived from surface waters. The median contribution to total cytotoxicity was 0.2% for regulated DBPs and 16% for the unregulated DBPs of current research interest. Nonvolatile, uncharacterized DBPs and anthropogenic contaminants accounted for 83% of total cytotoxicity. Potable reuse waters treated by reverse osmosis are not more cytotoxic than groundwaters. Even in the absence of reverse osmosis, reuse waters are less cytotoxic than surface drinking waters. Our results suggest that potable reuse can provide a safe, energy-efficient and cost-effective alternative water supply.

Tracing enhanced oil recovery signatures in casing gases from the Lost Hills oil field using noble gases

Earth and Planetary Science Letters (Elsevier) | August 15th, 2018

Enhanced oil recovery (EOR) and hydraulic fracturing practices are commonly used methods to improve hydrocarbon extraction efficiency; however, the environmental effects

Enhanced oil recovery (EOR) and hydraulic fracturing practices are commonly used methods to improve hydrocarbon extraction efficiency; however, the environmental effects of such practices remain poorly understood. EOR is particularly prevalent in oil fields throughout California where water resources are in high demand and the disposal of large volumes of produced water may affect groundwater quality. Consequently, it is essential to better understand the fate of injected (EOR) fluids in California, and other subsurface petroleum systems, as well as any potential effect on nearby aquifer systems. Noble gases can be used as tracers to understand hydrocarbon generation, migration, and storage conditions, as well as the relative proportions of oil and water present in the subsurface. In addition, a noble gas signature diagnostic of injected (EOR) fluids can be readily identified. We report noble gas isotope and concentration data in casing gases from oil production wells in the Lost Hills oil field, northwest of Bakersfield, California, and injectate gas data from the Fruitvale oil field, located within the city of Bakersfield. Casing and injectate gas data are used to: 1) establish pristine hydrocarbon noble-gas signatures and the processes controlling noble gas distributions, 2) characterize the noble gas signature of injectate fluids, 3) trace injectate fluids in the subsurface, and 4) construct a model to estimate EOR efficiency. Noble gas results range from pristine to significantly modified by EOR, and can be best explained using a solubility exchange model between oil and connate/formation fluids, followed by gas exsolution upon production. This model is sensitive to oil–water interaction during hydrocarbon expulsion, migration, and storage at reservoir conditions, as well as any subsequent modification by EOR.

Tracking California’s striking water storage gains attributed to intensive atmospheric rivers

Journal of Hydrology (Elsevier) | February 5th, 2025

California is highly vulnerable to extreme precipitation events due to the dense landfall of atmospheric rivers (ARs) during the winter months, often resulting in catastr

California is highly vulnerable to extreme precipitation events due to the dense landfall of atmospheric rivers (ARs) during the winter months, often resulting in catastrophic consequences such as widespread floods, mudslides, and landslides. This study focuses on the recovery of daily variations in AR-driven terrestrial water storage (TWS), which produces geodetically detectable ground subsidence. We invert GNSS vertical positions to obtain daily estimates of equivalent water height (EWH) through a variational Bayesian principal component analysis (vbPCA) based inversion scheme and track significant water gains during record-setting winter months in four water years (WYs) 2011, 2017, 2019, and 2023. These precipitation extremes have resulted in a substantial short-term increase in water storage, as evidenced by the multi-source EWH datasets (GNSS, GRACE, and NLDAS). Notably, WY 2023 experienced the highest snowfall due to the landfalls of high-density, high-category ARs, while WY 2017 recorded the highest precipitation totals, driven by the most frequent occurrence of hazardous ARs. Our findings further highlight that GNSS can accurately detect exceptionally wet hydrological events on short time scales, benefiting from an improved signal-to-noise ratio due to substantial increase in water storage. The results also indicate that while these extreme water years can help alleviate surface subsidence in the Central Valley caused by groundwater overexploitation, it is insufficient to alter California’s heavy reliance on groundwater for its intensive agricultural activities. Our findings demonstrate that GNSS is successful in tracking prodigious water increases from short-term precipitation extremes that are weaker than powerful hurricanes, illuminating the prospect of GNSS in supporting water management and flood preparedness.