Interactions between snow cover and evaporation lead to higher sensitivity of streamflow to temperature

Nature Portfolio (Springer Nature) | December 4th, 2020

Estimates of potential evaporation often neglect the effects of snow cover on evaporation process. Here, we present a definition of potential evaporation that explicitly

Estimates of potential evaporation often neglect the effects of snow cover on evaporation process. Here, we present a definition of potential evaporation that explicitly accounts for landscapes that are partially covered by snow. We show that, in the presence of snowpack, our evaporation estimates differ from conventional methods that assume evaporation from a free water surface. Specifically, we find that conventional methods overestimate potential evaporation as well as aridity, taken as the ratio of atmospheric water demand to supply, in landscapes where snowfall is significant. With dwindling snow-cover, actual aridity increases, which could explain the reduction in streamflow with decreasing snowfall. We suggest that streamflow, and hence water availability, is more sensitive to temperature changes in colder than in warmer regions.

Interbasin Ground-Water Flow in Southern Nevada

Nevada Bureau of Mines and Geology | March 1st, 1974

Interbasin water transfers in the United States and Canada

Nature Portfolio (Springer Nature) | January 13th, 2023

Interbasin water transfers (IBTs) can have a significant impact on the environment, water availability, and economies within the basins importing and exporting water, as

Interbasin water transfers (IBTs) can have a significant impact on the environment, water availability, and economies within the basins importing and exporting water, as well as basins downstream of these water transfers. The lack of comprehensive data identifying and describing IBTs inhibits understanding of the role IBTs play in supplying water for society, as well as their collective hydrologic impact. We develop three connected datasets inventorying IBTs in the United States and Canada, including their features, geospatial details, and water transfer volumes. We surveyed the academic and gray literature, as well as local, state, and federal water agencies, to collect, process, and verify IBTs in Canada and the United States. Our comprehensive IBT datasets represent all known transfers of untreated water that cross subregion (US) or subdrainage area (CA) boundaries, characterizing a total of 641 IBT projects. The infrastructure-level data made available by these data products can be used to close water budgets, connect water supplies to water use, and better represent human impacts within hydrologic and ecosystem models.

Investigating Runoff Efficiency in Upper Colorado River Streamflow Over Past Centuries

American Geophysical Union (AGU) | January 5th, 2018

With increasing concerns about the impact of warming temperatures on water resources, more attention is being paid to the relationship between runoff and precipitat

With increasing concerns about the impact of warming temperatures on water resources, more attention is being paid to the relationship between runoff and precipitation, or runoff efficiency. Temperature is a key influence on Colorado River runoff efficiency, and warming temperatures are projected to reduce runoff efficiency. Here, we investigate the nature of runoff efficiency in the upper Colorado River (UCRB) basin over the past 400 years, with a specific focus on major droughts and pluvials, and to contextualize the instrumental period. We first verify the feasibility of reconstructing runoff efficiency from tree‐ring data. The reconstruction is then used to evaluate variability in runoff efficiency over periods of high and low flow, and its correspondence to a reconstruction of late runoff season UCRB temperature variability. Results indicate that runoff efficiency has played a consistent role in modulating the relationship between precipitation and streamflow over past centuries, and that temperature has likely been the key control. While negative runoff efficiency is most common during dry periods, and positive runoff efficiency during wet years, there are some instances of positive runoff efficiency moderating the impact of precipitation deficits on streamflow. Compared to past centuries, the 20th century has experienced twice as many high flow years with negative runoff efficiency, likely due to warm temperatures. These results suggest warming temperatures will continue to reduce runoff efficiency in wet or dry years, and that future flows will be less than anticipated from precipitation due to warming temperatures.

Irrigation Water Use in the Central Valley of California

California Department of Water Resources (DWR) | January 1st, 1985

Just the Facts: Land, Water, and Agriculture in the Colorado River Basin

Babbitt Center for Land and Water Policy (Babbitt Center) | March 1st, 2022

Land Use/Water Supply Analysis Guidebook

Northern California Water Association | November 13th, 2008

The primary objective of the Land Use/ Water Supply Guidebook (Guidebook) is to provide members of the Northern California Water Association (NCWA) with practical inform

The primary objective of the Land Use/ Water Supply Guidebook (Guidebook) is to provide members of the Northern California Water Association (NCWA) with practical information to assist them with review or preparation of water supply and demand analyses as part of local land use planning processes. Through a broader understanding of the statutory requirements and relevant analytical methods, NCWA members can help ensure that Sacramento Valley land use planning efforts effectively consider water resources management issues. The Guidebook builds upon the successful efforts of the participants in the Sacramento Valley Integrated Regional Water Management Plan (IRWMP), which recognize that rapidly changing water use patterns in the Sacramento Valley are impacting business decisions. At the center of this change in Sacramento Valley water use patterns are the changes in land use in a historically agricultural region, driven primarily by urban development that is relying almost exclusively upon groundwater resources to meet new demands. Additionally, changing cropping patterns and managed wetlands may require additional water supplies. The Guidebook will highlight opportunities to maximize Sacramento Valley water resources and to avoid conflict by identifying the primary processes in California for linking water supply planning and land use planning at the local government level. The Guidebook focuses upon the water supply planning components in relevant land use planning documents, the assumptions used to develop the data and the conclusions, and considerations of the typical scope and depth of the required elements. By clearly identifying the range of reasonable assumptions, water managers, land use planners, special district board members, and local government staff and officials may effectively coordinate their efforts as part of the IRWMP and continue practicing integrated regional water management.

Landsat and Water—Case Studies of the Uses and Benefits of Landsat Imagery in Water Resources

U.S. Geological Survey (USGS) | March 20th, 2014

Water availability and allocation are issues gaining a great deal of attention, particularly in arid climates. Increases in population growth and recent droughts bring ur

Water availability and allocation are issues gaining a great deal of attention, particularly in arid climates. Increases in population growth and recent droughts bring urgency to measuring and monitoring water use in areas such as the western United States, where the majority of the water has already been allocated.  In the world of water resource management, Landsat has played a key role in providing objective and continuous data for the United States, particularly in the arid west. Water-related benefits of Landsat imagery are also reaped far beyond the United States’ borders in countries such as Chile, Australia, Morocco, Sudan, and Venezuela, which are using Landsat data to make informed decisions regarding natural resource allocation and use. 

Large global-scale vegetation sensitivity to daily rainfall variability

Nature Portfolio (Springer Nature) | December 11th, 2024

Click here for a plain language summary from NASA.

Click here for a plain language summary from NASA.

Learning from Crises to Build Urban Water Security

Rand Corporation (Rand) | January 15th, 2025

In this report, the authors examine the experiences of five cities — Cape Town, South Africa; Melbourne, Australia; São Paulo, Brazil; and Las Vegas, Nevada, and New O

In this report, the authors examine the experiences of five cities — Cape Town, South Africa; Melbourne, Australia; São Paulo, Brazil; and Las Vegas, Nevada, and New Orleans, Louisiana, in the United States — facing severe or catastrophic water supply risks to identify steps that could be taken ahead of time to mitigate those risks and build urban water security.