Socio‐ecohydrology and the urban water challenge

Ecohydrology (Wiley) | March 11th, 2011

Urban water systems are highly engineered. However, hydrology and ecology are still closely linked in semi‐arid urban ecosystems in which surface characteristics, veget

Urban water systems are highly engineered. However, hydrology and ecology are still closely linked in semi‐arid urban ecosystems in which surface characteristics, vegetation, and water flows are all highly transformed. Although these systems are human‐dominated, there are many uncertainties in the water budgets of semi‐arid cities, because evapotranspiration, runoff, groundwater recharge, and leakage are poorly constrained. Decision‐making, governance, and socioeconomic factors play important roles in determining urban hydrologic budgets. We offer a framework to integrate these factors in studies that combine biophysical and social dimensions of the urban water system using the example of western US cities, which are facing critical issues in water supply and demand, and which can benefit from a more comprehensive understanding of the factors that determine water consumption, distribution and availability. Because of the severity of the water crisis in the western US, and the biophysical, institutional, and cultural barriers to developing and implementing new water management practices, this region provides useful lessons for addressing water challenges in other regions.

Solar and wind energy enhances drought resilience and groundwater sustainability

Nature Portfolio (Springer Nature) | November 6th, 2019

Water scarcity brings tremendous challenges to achieving sustainable development of water resources, food, and energy security, as these sectors are often in co

Water scarcity brings tremendous challenges to achieving sustainable development of water resources, food, and energy security, as these sectors are often in competition, especially during drought. Overcoming these challenges requires balancing trade-offs between sectors and improving resilience to drought impacts. An under-appreciated factor in managing the water-food-energy (WFE) nexus is the increased value of solar and wind energy (SWE). Here we develop a trade-off frontier framework to quantify the water sustainability value of SWE through a case study in California. We identify development pathways that optimize the economic value of water in competition for energy and food production while ensuring sustainable use of groundwater. Our results indicate that in the long term, SWE penetration creates beneficial feedback for the WFE nexus: SWE enhances drought resilience and benefits groundwater sustainability, and in turn, maintaining groundwater at a sustainable level increases the added value of SWE to energy and food production.

Southern California winter precipitation variability reflected in 100-year ocean salinity record

Nature Portfolio (Springer Nature) | April 27th, 2023

Rainfall in southern California is highly variable, with some fluctuations explainable by climate patterns. Resulting runoff and heightened streamflow from rain events in

Rainfall in southern California is highly variable, with some fluctuations explainable by climate patterns. Resulting runoff and heightened streamflow from rain events introduces freshwater plumes into the coastal ocean. Here we use a 105-year daily sea surface salinity record collected at Scripps Pier in La Jolla, California to show that El Niño Southern Oscillation and Pacific Decadal Oscillation both have signatures in coastal sea surface salinity. Averaging the freshest quantile of sea surface salinity over each year’s winter season provides a useful metric for connecting the coastal ocean to interannual winter rainfall variability, through the influence of freshwater plumes originating, at closest, 7.5 km north of Scripps Pier. This salinity metric has a clear relationship with dominant climate phases: negative Pacific Decadal Oscillation and La Niña conditions correspond consistently with lack of salinity anomaly/ dry winters. Fresh salinity anomalies (i.e., wet winters) occur during positive phase Pacific Decadal Oscillation and El Niño winters, although not consistently. This analysis emphasizes the strong influence that precipitation and consequent streamflow has on the coastal ocean, even in a region of overall low freshwater input, and provides an ocean-based metric for assessing decadal rainfall variability.

Southern Nevada Water Authority 2026 Water Resource Plan

Southern Nevada Water Authority (SNWA) | July 22nd, 2026

Southwestern United States drought of the 21st century presages drier conditions into the future

Nature Portfolio (Springer Nature) | September 19th, 2022

Intense drought has occurred in the United States Southwest this century, causing unprecedented stress to water resources. Here we use paleoclimate and instrumental reco

Intense drought has occurred in the United States Southwest this century, causing unprecedented stress to water resources. Here we use paleoclimate and instrumental records to establish that the recent temperature rise is incompatible with random draws from past fluctuations, including the current period of warming. Consistent with and extending previous reconstructions, we find that the ongoing drought is the most intense at the 21-year scale back to 600 CE. Evaluation using standardized regression coefficients shows that recent warming damps the effect of moisture delivery on the Standardized Precipitation-Evaporation Index by approximately one-third. The probability of full recovery of the current moisture deficit is unlikely even by mid-century and about five percent in 10-15 years. Evaluation of future climate simulations indicates increasing regional temperature stress and soil moisture depletion, and coupled with long recovery periods for moisture delivery, very low chance for regional mega-reservoirs to regain full-capacity levels assuming current demand.

Spatial based drought assessment: Where are we heading? A review on the current status and future

Science of the Total Environment (Elsevier) | July 13th, 2022

Droughts are the most spatially complex natural hazards that exert global impacts and are further aggravated by climate change. The investigation of drought events is cha

Droughts are the most spatially complex natural hazards that exert global impacts and are further aggravated by climate change. The investigation of drought events is challenging as it involves numerous factors ranging from detection and assessment to modelling, management and mitigation. The analysis of these factors and their quantitative assessments have significantly evolved in recent times. In this paper, we review recent methods used to examine and model droughts from a spatial viewpoint. Our analysis was conducted at three spatial scales (point-wise, regional and global) and we evaluated how recent spatial methods have advanced our understanding of drought through case study examples. Further, we also examine and provide a broad overview of relevant case studies related to future drought occurrences under climate change. This study is a comprehensive synthesis of the various quantitative techniques used to assess the spatial characteristics of droughts at different spatial scales, and not an exhaustive review of all drought aspects. However, this serves as a basis for understanding the key milestones and advances accomplished through new spatial concepts relative to the traditional approaches to study drought. This work also aims to address the gaps in knowledge that are in need of further attention and provides recommendations to improve our understanding of droughts.

Spatiotemporal patterns of U.S. drought awareness

Palgrave Communications | September 17th, 2019

Drought is a creeping climatological phenomenon with persistent precipitation deficits. Unlike rapid onset natural hazards such as floods and wildfires, the intan

Drought is a creeping climatological phenomenon with persistent precipitation deficits. Unlike rapid onset natural hazards such as floods and wildfires, the intangible and gradual characteristics of drought cause a lack of social response during the onset. The level of awareness of a local drought increases rapidly through mass media reports and online information searching activities when the drought reaches its peak severity. This high level of local drought awareness drives concerns for water shortage and support for water policy. However, spatiotemporal patterns of national-scale drought awareness have never been studied due to constraints imposed by time-consuming and costly survey data collection and surveys’ limited sample sizes. Here, we present the national-scale study to reveal the spatiotemporal patterns of drought awareness over the contiguous United States (CONUS) using Google Trends data and Principal Component Analysis (PCA). Results show that the first two PC modes can explain 48% (38% for PC1 and 10% for PC2) of the total variance of state-level drought awareness. We find that the PC1 mode relates to a national pattern of drought awareness across the CONUS. The spatiotemporal patterns further imply that residents in the Northeastern US region are the most aware of the emergence of drought, regardless of the geographic location of the occurrence. The results illustrate how big data, such as search query and social media data, can help develop an effective and efficient plan for drought mitigation in the future.

State of Arizona Motion to Intervene, State of Nevada v. Burgum

Arizona Department of Water Resources (ADWR) | October 16th, 2026

Recently, the Department of the Interior and the Bureau of Reclamation issued three agency actions that will govern the agencies’ release of water from federal dams and

Recently, the Department of the Interior and the Bureau of Reclamation issued three agency actions that will govern the agencies’ release of water from federal dams and reservoirs for the next decade.  If upheld, these actions would significantly reduce the supply of water available to the three States of the Lower Basin—Arizona, California, and Nevada—in violation of the 1922 Compact and related laws. Nevada brought this Administrative Procedure Act suit to challenge those agency actions and to protect its rights under the federal laws governing the Colorado River. Those same challenged actions affect Arizona at least as much as Nevada. Acting through the Director of the Arizona Department of Water Resources, see Ariz. Rev. Stat. § 45-105(A)(9), Arizona therefore moves to intervene and participate in the resolution of these critical issues.

State of Nevada v. Burgum

U.S. District Court for the District of Nevada | August 24th, 2026

Nevada and the other Lower Basin States submitted an alternative to the proposed action for inclusion in the NEPA analysis that Plaintiffs maintain fully complies with th

Nevada and the other Lower Basin States submitted an alternative to the proposed action for inclusion in the NEPA analysis that Plaintiffs maintain fully complies with the Law of the River and better satisfies the purpose and need of the proposed action than the preferred alternative in the Final EIS. Federal Defendants failed to consider and carry forward the Lower Basin States’ alternative. Instead, the Final EIS and ROD authorize the Secretary of the Interior to impose on Nevada an annual reduction of 213,556 acre-feet at a 3.6 maf shortage, which constitutes approximately 71% of Nevada’s Colorado River entitlement. Furthermore, the federal defendants failed to analyze critical components of the Law of the River that would lessen the shortage burden of the entire Lower Basin. The magnitude of such shortages will cause acute environmental, socioeconomic, and health and human safety impacts to southern Nevada. Federal Defendants failed to consider such impacts in any meaningful way in the Final EIS.

State Water Project and Central Valley Project Drought Contingency Plan May 1, 2021 – September 30, 2021

California Department of Water Resources (DWR) | May 28th, 2021

This Drought Contingency Plan (Drought Plan) is prepared by the California Department of Water Resources (DWR) and the U.S. Bureau of Reclamation (Reclamation) in an effo

This Drought Contingency Plan (Drought Plan) is prepared by the California Department of Water Resources (DWR) and the U.S. Bureau of Reclamation (Reclamation) in an effort to provide updated information about areas of potential concern given the current dry hydrology of 2021. DWR and Reclamation operate the State Water Project (SWP) and the Central Valley Project (CVP), respectively, to the 2020 Record of Decision (ROD) as analyzed in the 2019 U.S. Fish and Wildlife Service (USFWS) Biological Opinion and 2019 National Marine Fisheries Service (NMFS) Biological Opinion on the Coordinated Long-Term Operation of the Central Valley Project and the State Water Project (Collectively the 2019 Biological Opinions), and DWR also operates the SWP to the 2020 California Department of Fish and Wildlife (CDFW) Incidental Take Permit (ITP). This updated Drought Plan will be submitted by DWR to CDFW in response to Condition 8.21 of CDFW’s ITP. Concurrently, this plan will be shared with the Water Operations Management Team (WOMT) which includes representatives from DWR, Reclamation, USFWS, NMFS, CDFW, and the State Water Resources Control Board (SWRCB) (collectively referred to as Agencies). This report was first drafted in February and subsequently updated in March, April, and May 2021.