Achieving Realistic Runoff in the Western United States with a Land Surface Model Forced by Dynamically Downscaled Meteorology

American Meteorological Society (AMS) | February 14th, 2023

This study provides useful guidance for improving a land surface model to accurately represent runoff across a spatially extensive and hydroclimatically diverse region (t

This study provides useful guidance for improving a land surface model to accurately represent runoff across a spatially extensive and hydroclimatically diverse region (the western United States). The land surface model is updated to represent runoff more accurately at gauged basins, and then additionally updated for basins without observational data using a mathematical approach called the donor-basin method. We make use of a regional climate model’s reanalysis-derived meteorological data and its underlying land surface model to achieve realistic runoff. The calibrated land surface model can thus be tightly coupled in subsequent studies in a manner that should more accurately reflect runoff conditions. Findings from this study will serve as a useful reference for the atmospheric (and hydrologic) modeling communities and their ability to represent large-scale hydrology accurately.

Advances in Sub-seasonal to Seasonal Prediction Relevant to Water Management in the Western United States

American Meteorological Society (AMS) | July 21st, 2022

Water management in the semi-arid western United States (U.S.) is a challenging endeavor that evolves from year to year based on large-scale atmospheric and oceanic condi

Water management in the semi-arid western United States (U.S.) is a challenging endeavor that evolves from year to year based on large-scale atmospheric and oceanic conditions. This region has frequently experienced prolonged periods of drought with substantial socioeconomic impacts; the most recent instance involves California entering its third consecutive drought year. As context for the economic implications of drought, California’s enacted state budget for the Fiscal Year 2021-22 authorizes more than $600 million for the California Department of Water Resources for providing immediate drought support to local water agencies (CA State Budget 2021a); this amount is part of a package of more than $5 billion over four years for water resilience and drought preparedness (CA State Budget 2021b). For drought preparedness, state and local water managers would like to rely on skillful forecasts on timescales that span the spectrum between weather forecasts and climate predictions. Despite recent improvements in developing sub-seasonal (2- to 6-weeks lead) and seasonal (2- to 6-months lead) prediction systems that compete with and/or outperform existing dynamical and statistical models (e.g., Gibson et al. 2021, Switanek et al. 2020, DeFlorio et al. 2019), forecasting limitations have hindered crucial management decisions for western U.S. water managers, especially related to longer-lead planning, budgeting, resource allocation, and better preparedness for wet and dry extremes (DeFlorio et al. 2021). Improved understanding of physical phenomena and processes governing weather and climate extremes and utilization of emerging forecast methodologies are critical to developing skillful S2S forecast products relevant to water management.

Advances in Subseasonal to Seasonal Prediction Relevant to Water Management in the Western United States

American Meteorological Society (AMS) | October 1st, 2022

Water management in the semiarid western United States is a challenging endeavor that evolves from year to year based on large-scale atmospheric and oceanic conditions. T

Water management in the semiarid western United States is a challenging endeavor that evolves from year to year based on large-scale atmospheric and oceanic conditions. This region has frequently experienced prolonged periods of drought with substantial socioeconomic impacts; the most recent instance involves California entering its third consecutive drought year. As context for the economic implications of drought, California’s enacted state budget for the fiscal year 2021/22 authorizes more than $600 million for the California Department of Water Resources for providing immediate drought support to local water agencies (State of California 2021a); this amount is part of a package of more than $5 billion over 4 years for water resilience and drought preparedness (State of California 2021b). For drought preparedness, state and local water managers would like to rely on skillful forecasts on time scales that span the spectrum between weather forecasts and climate predictions. Despite recent improvements in developing subseasonal (2–6-weeks lead) and seasonal (2–6-months lead) prediction systems that compete with and/or outperform existing dynamical and statistical models (e.g., Gibson et al. 2021; Switanek et al. 2020; DeFlorio et al. 2019), forecasting limitations have hindered crucial management decisions for western U.S. water managers, especially related to longer-lead planning, budgeting, resource allocation, and better preparedness for wet and dry extremes (DeFlorio et al. 2021). Improved understanding of physical phenomena and processes governing weather and climate extremes and utilization of emerging forecast methodologies are critical to developing skillful subseasonal to seasonal (S2S) forecast products relevant to water management.

Agricultural managed aquifer recharge (Ag-MAR)—a method for sustainable groundwater management: A review

Critical Reviews in Environmental Science and Technology (Taylor & Francis) | March 28th, 2022

More than two billion people and 40% of global agricultural production depend upon unsustainable groundwater extraction. Managed aquifer recharge (MAR), the practice of s

More than two billion people and 40% of global agricultural production depend upon unsustainable groundwater extraction. Managed aquifer recharge (MAR), the practice of strategically recharging water to replenish subsurface storage, is an important subbasin scale practice for managing groundwater more sustainably. However, it is not yet reaching its full potential to counterbalance growing global groundwater demand. Agricultural managed aquifer recharge (Ag-MAR) is an emerging method for spreading large volume flows on agricultural lands and has capacity for widespread global implementation. Yet, knowledge gaps, synergies, and tradeoffs in Ag-MAR research still exist. We identify six key system considerations when implementing Ag-MAR: water source, soil and unsaturated zone processes, impact on groundwater, crop system suitability, climate change and impact on greenhouse gas emissions, and social and economic feasibility. We describe the present distribution, need for common terminology, and benefits of Ag-MAR including groundwater storage, increased environmental flows, and domestic wells support. We then outline major gaps, namely, water quality impacts, and crop health and yield. We showcase the multidisciplinary approach needed for communication and coordination of Ag-MAR programs with stakeholders and the public and provide a framework for implementation. Finally, we outline a vision for the path to Ag-MAR implementation. Ag-MAR is an important approach for achieving groundwater sustainability. However, it is one of many necessary solutions and does not offset the need for groundwater conservation.

Alaskan Water for California?: The Subsea Pipeline Option

United States Congress | January 1st, 1992

All-day fresh water harvesting by microstructured hydrogel membranes

Nature Portfolio (Springer Nature) | May 14th, 2021

Solar steam water purification and fog collection are two independent processes that could enable abundant fresh water generation. We developed a hydrogel membrane that c

Solar steam water purification and fog collection are two independent processes that could enable abundant fresh water generation. We developed a hydrogel membrane that contains hierarchical three-dimensional microstructures with high surface area that combines both functions and serves as an all-day fresh water harvester. At night, the hydrogel membrane efficiently captures fog droplets and directionally transports them to a storage vessel. During the daytime, it acts as an interfacial solar steam generator and achieves a high evaporation rate of 3.64 kg m−2 h−1 under 1 sun enabled by improved thermal/vapor flow management. With a homemade rooftop water harvesting system, this hydrogel membrane can produce fresh water with a daily yield of ~34 L m−2 in an outdoor test, which demonstrates its potential for global water scarcity relief.

Alleviating water scarcity by optimizing crop mixes

Nature Portfolio (Springer Nature) | November 6th, 2023

Alternative management paradigms for the future of the Colorado and Green Rivers

U.S. Department of Agriculture (USDA) | January 28th, 2021

The Colorado River is among the most extensively managed river systems in the world. The river’s headwaters are within the Rocky Mountains in the United States. From t

The Colorado River is among the most extensively managed river systems in the world. The river’s headwaters are within the Rocky Mountains in the United States. From there, it flows through the arid lands of the Colorado Plateau and the Basin-and-Range to its delta in northwestern Mexico. Here, the river is the only significant water supply in an otherwise starkly arid landscape and has long been called “America’s Nile.” It provides a critical water supply for nearly four million acres of irrigated land, municipal supplies for 30 million people located within and outside the basin, and more than 4,200 MW of hydropower generation capacity. The Colorado River and some of its tributaries also provide an existing or potential water supply for at least 15 Native American tribes. The river flows through seven National Wildlife Refuges, four National Recreation Areas, and five National Parks. Today, the annual consumptive uses and losses of streamflow in the basin typically exceed the amount of water available, and the river rarely flows into the Gulf of California. The impacts of climate change are likely to decrease future runoff and intensify droughts, thereby threatening current and future uses in the basin. Clearly, new ways of thinking about and managing the river need to be sought and implemented.

Alternative Water Transfers in Colorado: A Review of Alternative Transfer Mechanisms for Front Range Municipalities

Environmental Defense Fund (EDF) | November 1st, 2016

Alternative water transfers (ATMs) refer to various methods, activities, and frameworks that have been established to transfer water on a temporary or intermittent basis

Alternative water transfers (ATMs) refer to various methods, activities, and frameworks that have been established to transfer water on a temporary or intermittent basis, primarily from agriculture to other uses. They are labeled as “alternative” because they represent a type of water transfer that does not result in the permanent dry-up of agricultural land, which has been the primary form of water transfers in much of Colorado for decades. ATMs are a body of activities that represent general frameworks or concepts to be molded to the specific conditions of a place and need. The Environmental Defense Fund (EDF) obtained a grant opportunity to fund research, analysis, and outreach toward the development of ATMs with the potential to improve the financial returns and long-term viability of farming, maintain or improve streamflows which support environmental and recreational activities, and provide a cost-effective means for municipalities to maintain water supply reliability into the future. The purpose of this project is to develop a comprehensive financial comparison of the water supply development options currently pursued by municipalities to applicable ATMs and to develop recommendations that can increase the application of specific ATM structures with the potential joint benefits to municipal and agricultural water users.

Amplification of downstream flood stage due to damming of fine-grained rivers

Nature Portfolio (Springer Nature) | June 1st, 2022

River dams provide many benefits, including flood control. However, due to constantly evolving channel morphology, downstream conveyance of floodwaters following dam clo

River dams provide many benefits, including flood control. However, due to constantly evolving channel morphology, downstream conveyance of floodwaters following dam closure is difficult to predict. Here, we test the hypothesis that the incised, enlarged channel downstream of dams provides enhanced water conveyance, using a case study from the lower Yellow River, China. We find that, although flood stage is lowered for small floods, counterintuitively, flood stage downstream of a dam can be amplified for moderate and large floods. This arises because bed incision is accompanied by sediment coarsening, which facilitates development of large dunes that increase flow resistance and reduce velocity relative to pre-dam conditions. Our findings indicate the underlying mechanism for such flood amplification may occur in >80% of fine-grained rivers, and suggest the need to reconsider flood control strategies in such rivers worldwide.