Evaluating Collaborative Institutions in Context: The Case of Regional Water Management in Southern California

Sage Journals | January 1st, 2014

Regional collaborative institutions are seen as tools for improving collaboration and for reducing the inefficiency of fragmented management and planning. However, recent

Regional collaborative institutions are seen as tools for improving collaboration and for reducing the inefficiency of fragmented management and planning. However, recent research has shown that the ability of new regional institutions to achieve these aims is contingent upon their relationship to the existing institutional landscape. This paper uses network analyses of six newly created Integrated Regional Water Management (IRWM) subregions in southern California to examine how their introduction intersects existing water management systems and whether the patterns of interaction in water planning have changed as a result. The results further our understanding of collaborative governance and regionalism by showing that the ability of regional institutions to facilitate new interactions can vary widely across a given institutional landscape. Further, while IRWM has helped to strengthen the water management network in southern California, it has not replaced existing watershed planning efforts. Interviews with water managers reveal there is support for IRWM but it is still too early to evaluate its effectiveness. Further research should explore the drivers and consequences of heterogeneity in IRWM and whether the incentives for participation are sufficient.

Evaluating effects of potential urban water use efficiency standards (AB 1668-SB 606) on urban retail water suppliers, wastewater management agencies, and urban landscapes (trees and urban parklands)**

California State Water Resources Control Board (SWRCB) | January 15th, 2022

Click here for the draft report segment on wastewater.

Click here for the draft report segment on wastewater.

Evaluating effects of urban water use efficiency standards (AB 1668- SB 606) on urban retail water suppliers, wastewater management agencies, and urban landscapes (trees and urban parklands)*

California State Water Resources Control Board (SWRCB) | January 15th, 2022

Click here for the companion draft chapter on trees and parkland

Click here for the companion draft chapter on trees and parkland

Evaluating GFS and ECMWF Ensemble Forecasts of Integrated Water Vapor Transport along the U.S. West Coast

American Meteorological Society (AMS) | October 28th, 2022

Atmospheric rivers (ARs) are long and narrow regions in the atmosphere of enhanced integrated water vapor transport (IVT) and can produce extreme precipitation and high s

Atmospheric rivers (ARs) are long and narrow regions in the atmosphere of enhanced integrated water vapor transport (IVT) and can produce extreme precipitation and high societal impacts. Reliable and skillful forecasts of landfalling ARs in the western United States are critical to hazard preparation and aid in decision support activities, such as Forecast-Informed Reservoir Operations (FIRO). The purpose of this study is to compare the cool-season water year skill of the NCEP Global Ensemble Forecast System (GEFS) and ECMWF Ensemble Prediction System (EPS) forecasts of IVT along the U.S. West Coast for 2017–20. The skill is analyzed using probability-over-threshold forecasts of IVT magnitudes ≥ 250 kg m−1 s−1 (P250) using contingency table skill metrics in coastal Northern California and along the west coast of North America. Analysis of P250 with lead time (dProg/dt) found that the EPS provided ∼1 day of additional lead time for situational awareness over the GEFS at lead times of 6–10 days. Forecast skill analysis highlights that the EPS leads over the GEFS with success ratios 0.10–0.15 higher at lead times > 6 days for P250 thresholds of ≥25% and ≥50%, while event-based skill analysis using the probability of detection (POD) found that both models were largely similar with minor latitudinal variations favoring higher POD for each model in different locations along the coast. The relative skill of the EPS over the GEFS is largely attributed to overforecasting by the GEFS at longer lead times and an increase in the false alarm ratio.

Evaluating groundwater quality influences from oil field operations and other anthropogenic activities in an urban setting, Santa Fe Springs, California

Science of the Total Environment (Elsevier) | June 22nd, 2026

Groundwater quality is often affected by anthropogenic activities in urban settings. This study examines groundwater quality in and around the Santa Fe Springs Oil Field

Groundwater quality is often affected by anthropogenic activities in urban settings. This study examines groundwater quality in and around the Santa Fe Springs Oil Field in Los Angeles County, California, where oil and gas production commonly intersects with high density industrial, commercial and residential land uses. Utilizing a combination of new and historical data, we evaluated potential pathways that would allow for oil field formation fluids to migrate into groundwater and whether mixing may have occurred based on the distribution of groundwater and oil field formation fluid tracers in samples. Samples were analyzed for a wide array of constituents including volatile organic compounds, light hydrocarbons, major ions, and various isotopic compositions. Despite evidence of oil field infrastructure providing potential pathways of migration via uncemented annular spaces, casing breaches and historical disposal of oil field formation water in surface ponds, the distribution and occurrence of stable isotopes of water, chloride, boron, and total dissolved solids do not indicate mixing of oil field formation water and groundwater. However, methane isotopic signatures and the presence of heavier alkanes suggest gas from oil-bearing formations have migrated from depth via oil field well infrastructure. Volatile organic compound detections were mainly from manufactured compounds unrelated to oil and gas production, with a relatively limited number of petroleum hydrocarbons also detected. Volatile organic compounds were generally found in wells tapping shallow, modern aged groundwater, indicating anthropogenic activities occurring at or near land surface as the source. Study results suggest that while oil field infrastructure provides migration pathways for oil field formation fluids to be introduced into groundwater, urban land uses not related to oil and gas production are the primary drivers of groundwater quality degradation.

Evaluating historical changes in a mussel bed community in northern California

Nature Portfolio (Springer Nature) | January 14th, 2025

Evaluating Micrometeorological Estimates of Groundwater Discharge from Great Basin Desert Playas

National Groundwater Association (NGWA) | March 6th, 2018

Groundwater availability studies in the arid southwestern United States traditionally have assumed that groundwater discharge by evapotranspiration (ETg) from desert play

Groundwater availability studies in the arid southwestern United States traditionally have assumed that groundwater discharge by evapotranspiration (ETg) from desert playas is a significant component of the groundwater budget. However, desert playa ETg rates are poorly constrained by Bowen ratio energy budget (BREB) and eddy‐covariance (EC) micrometeorological measurement approaches. Best attempts by previous studies to constrain ETg from desert playas have resulted in ETg rates that are within the measurement error of micrometeorological approaches. This study uses numerical models to further constrain desert playa ETg rates that are within the measurement error of BREB and EC approaches, and to evaluate the effect of hydraulic properties and salinity‐based groundwater density contrasts on desert playa ETg rates. Numerical models simulated ETg rates from desert playas in Death Valley, California and Dixie Valley, Nevada. Results indicate that actual ETg rates from desert playas are significantly below the uncertainty thresholds of BREB‐ and EC‐based micrometeorological measurements. Discharge from desert playas likely contributes less than 2% of total groundwater discharge from Dixie and Death Valleys, which suggests discharge from desert playas also is negligible in other basins. Simulation results also show that ETg from desert playas primarily is limited by differences in hydraulic properties between alluvial fan and playa sediments and, to a lesser extent, by salinity‐based groundwater density contrasts.

Evaluating the Accuracy of Reclamation’s 24-Month Study Lake Powell Projections

Utah State University | February 18th, 2022

The bias for inflow predictions will likely be reduced now that the reference period includes a more recent, and somewhat drier, span of time, but projections of future i

The bias for inflow predictions will likely be reduced now that the reference period includes a more recent, and somewhat drier, span of time, but projections of future inflows are likely to remain biased, because the hydrology of the 1991-2020 reference period was still wetter than the current Millennium Drought.

Evaluating the Effects of Turf-Replacement Programs in Los Angeles County

University of California, Los Angeles (UCLA) | August 4th, 2017

In 2014, the Metropolitan Water District of Southern California (MWD) undertook an unprecedented investment to incentive turf replacement throughout Southern California i

In 2014, the Metropolitan Water District of Southern California (MWD) undertook an unprecedented investment to incentive turf replacement throughout Southern California in response to the state’s serious drought. MWD devoted $350 million to the program, resulting in more than 46,000 rebate payments to remove 165 million square feet of turf. The funding boost served as a tremendous natural experiment to better understand the effects turf replacement programs. As part of an evaluation of this program, UCLA and the University of Utah examined socio-economic and demographic characteristics of program participation and assessed changes in vegetation and landscapes of front yards resulting from turf replacement. We examined address-level records of 24,921 participants who applied for turf replacement rebates between February 2014 and April 2016 in Los Angeles (LA) County. We analyzed the socioeconomic and spatial determinants of program participation. Further, we used Google Earth Street View to characterize the landscapes and plants resulting from turf replacement based on a set of randomly selected participating properties. We ascertained the types of turf replacements that were installed and developed a classification system for landscape design types.

Evaluating the environmental impact of cleaning the North Pacific Garbage Patch

Nature Portfolio (Springer Nature) | May 27th, 2025