Water Resources Systems Planning and Management: An Introduction to Methods, Models and Applications

United Nations (UN) | January 1st, 2017

Throughout history, much of the world has witnessed ever-greater demands for reliable, high-quality and inexpensive water supplies for domestic consumption, agriculture,

Throughout history, much of the world has witnessed ever-greater demands for reliable, high-quality and inexpensive water supplies for domestic consumption, agriculture, and industry. In recent decades there have also been increasing demands for hydrological regimes that support healthy and diverse ecosystems, provide for water-based recreational activities, reduce if not prevent floods and droughts, and in some cases, provide for the production of hydropower and ensure water levels adequate for ship navigation. Water managers are challenged to meet these multiple and often conflicting demands. At the same time, public stakeholder interest groups have shown an increasing desire to take part in the water resources development and management decision-making process. Added to all these management challenges are the uncertainties of natural water supplies and demands due to changes in our climate, changes in people's standards of living, changes in watershed land uses and changes in technology. How can managers develop, or redevelop and restore, and then manage water resources systems - systems ranging from small watersheds to those encompassing large river basins and coastal zones - in a way that meets society's changing objectives and goals? In other words, how can water resources systems become more integrated and sustainable?

Water shortage risks from perennial crop expansion in California's Central Valley

Environmental Research Letters (IOP) | October 15th, 2019

California's Central Valley is one of the world's most productive agricultural regions. Its high-value fruit, vegetable, and nut crops rely on surface water imports from

California's Central Valley is one of the world's most productive agricultural regions. Its high-value fruit, vegetable, and nut crops rely on surface water imports from a vast network of reservoirs and canals as well as groundwater, which has been substantially overdrafted to support irrigation. The region has undergone a shift to perennial (tree and vine) crops in recent decades, which has increased water demand amid a series of severe droughts and emerging regulations on groundwater pumping. This study quantifies the expansion of perennial crops in the Tulare Lake Basin, the southern region of the Central Valley with limited natural water availability. A gridded crop type dataset is compiled on a 1 mi2 spatial resolution from a historical database of pesticide permits over the period 1974–2016 and validated against aggregated county-level data. This spatial dataset is then analyzed by irrigation district, the primary spatial scale at which surface water supplies are determined, to identify trends in planting decisions and agricultural water demand over time. Perennial crop acreage has nearly tripled over this period, and currently accounts for roughly 60% of planted area and 80% of annual revenue. These trends show little relationship with water availability and have been driven primarily by market demand. From this data, we focus on the increasing minimum irrigation needs each year to sustain perennial crops. Results indicate that under a range of plausible future regulations on groundwater pumping ranging from 10% to 50%, water supplies may fail to consistently meet demands, increasing losses by up to 30% of annual revenues. More broadly, the datasets developed in this work will support the development of dynamic models of the integrated water-agriculture system under uncertain climate and regulatory changes to understand the combined impacts of water supply shortages and intensifying irrigation demand.

Water Special Districts: A Look at Governance and Public Participation

Legislative Analyst's Office (LAO) | March 15th, 2002

Chapter 107, Statutes of 2001 (AB 38, Strom-Martin), requires the Legislative Analyst’s Office to undertake a study of these special districts. In this review we find t

Chapter 107, Statutes of 2001 (AB 38, Strom-Martin), requires the Legislative Analyst’s Office to undertake a study of these special districts. In this review we find that while some individual districts have pursued controversial policies, there is no evidence of a statewide structural governance problem.

Water Stress and a Changing San Joaquin Valley

Public Policy Institute of California (PPIC) | March 1st, 2017

The San Joaquin Valley—California’s largest agricultural region, and an important contributor to the nation’s food supply—is in a time of great change and growing

The San Joaquin Valley—California’s largest agricultural region, and an important contributor to the nation’s food supply—is in a time of great change and growing water stress. Agriculture is a leading economic driver and the predominant water user. The region’s farms and related manufacturing businesses account for 25 percent of the valley’s revenues and 16 percent of local jobs—and 89 percent of annual net water use. The latest drought underscored valley agriculture’s vulnerability to water scarcity and long-term declines in groundwater reserves. The region has a greater abundance of productive farmland than local water supplies for irrigation. In most years since the mid-1980s, groundwater has been used faster than it is being replenished (“groundwater overdraft”). Over the past three decades, overdraft has averaged nearly 2 million acre-feet per year, or 13 percent of net water use. This has contributed to increased pumping costs, dry wells, sinking lands, and declining reliability of this vital drought reserve.

Water Supply Conditions in Southern California during 1958-1959, Volume II, Water Level Data, Central Coastal and Los Angeles Regions

California Department of Water Resources (DWR) | May 1st, 1961

Water Surplus and Drought Management Update - Conditions as of 11/29/2022

Metropolitan Water District of Southern California (MWD) | December 13th, 2022

Water transfers (Resource Management Strategy)

California Department of Water Resources (DWR) | July 29th, 2016

The California Water Code (CWC) defines a water transfer as a temporary or long-term change in the point of diversion, place of use, or purpose of use due to a transfer,

The California Water Code (CWC) defines a water transfer as a temporary or long-term change in the point of diversion, place of use, or purpose of use due to a transfer, sale, lease, or exchange of water or water rights. Temporary water transfers have a duration of one year or less (CWC Section 1725). Long-term water transfers have a duration of more than one year (CWC Section 1728). Transfers can be between water districts that are neighboring or across the state, provided there is a means to convey or store the water. A water transfer can be a temporary or permanent sale of water or a water right by the water right holder, a lease of the right to use water from the water right holder, or a sale or lease of a contractual right to water supply. Water transfers can also take the form of long-term contracts for the purpose of improving long-term supply reliability.

Water Year 2023: Weather Whiplash, from Drought to Deluge

California Department of Water Resources (DWR) | October 4th, 2023

Water Year 2023 demonstrated California’s high climate variability, ending the state’s driest consecutive three-year period with one of the snowiest years of record.

Water Year 2023 demonstrated California’s high climate variability, ending the state’s driest consecutive three-year period with one of the snowiest years of record. Even though California has been experiencing a theme of aridity in the 21st century (the statewide droughts of 2007-2009, 2012-2019, and 2020-2022), Water Year 2017 was the state’s second wettest in terms of statewide precipitation. Climate change is expected to amplify naturally occurring variability in the long term, potentially result in a shorter wet season for California but one with more extreme atmospheric river storms and hence potentially greater flood damage risk.

Water, energy and environment nexus: The California experience

International Journal of Water Resources Development (Taylor & Francis) | July 21st, 2010

The paper addresses the local and inter-state connections between water, energy and the environment. Using California and the western USA as a case study, the paper highl

The paper addresses the local and inter-state connections between water, energy and the environment. Using California and the western USA as a case study, the paper highlights the difficulties of balancing the needs of diverse stakeholders and protecting valuable resources while providing reliable and safe supplies of both water and energy to agricultural, industrial and residential customers. The investigation of these complex relationships is necessary to inform local and national policy decisions regarding the management of water, energy and the environment.

Water, environment, and socioeconomic justice in California: A multi-benefit framework

Science of the Total Environment (Elsevier) | November 5th, 2022

Low-income, rural frontline communities of California's Central Valley experience environmental and socioeconomic injustice, water insecurity, extremely poor air quality,

Low-income, rural frontline communities of California's Central Valley experience environmental and socioeconomic injustice, water insecurity, extremely poor air quality, and lack of fundamental infrastructure (sewage, green areas, health services), which makes them less resilient. Many communities depend financially on agriculture, while water scarcity and associated policy may trigger farmland retirement, further hindering socioeconomic opportunities. Here we propose a multi-benefit framework to repurpose cropland in buffers inside and around (400-m and 1600-m buffers) 154 rural disadvantaged communities of the Central Valley to promote socioeconomic opportunities, environmental benefits, and business diversification. We estimate the potential for (1) reductions in water and pesticide use, nitrogen leaching, and nitrogen gas emissions, (2) managed aquifer recharge, and (3) economic and employment impacts associated with clean industries and solar energy. Retiring cropland within 1600-m buffers can result in reductions in annual water use of 2.18 km3/year, nitrate leaching into local aquifers of 105,500 t/year, greenhouse gas emissions of 2,232,000 t CO2-equivalent/year, and 5388 t pesticides/year, with accompanying losses in agricultural revenue of US$4213 million/year and employment of 25,682 positions. Buffer repurposing investments of US$27 million/year per community for ten years show potential to generate US$101 million/year per community (total US$15,578 million/year) for 30 years and 407 new jobs/year (total 62,697 jobs/year) paying 67 % more than prior farmworker jobs. In the San Joaquin Valley (southern Central Valley), where groundwater overdraft averages 2.3 km3/year, potential water use reduction is 1.8 km3/year. We have identified 99 communities with surficial soils adequate for aquifer recharge and canals/rivers within 1600 m. This demonstrates the potential of managed aquifer recharge in buffered zones to substantially reduce overdraft. The buffers framework shows that well-planned land repurposing near disadvantaged communities can create multiple benefits for agriculture and industry stakeholders, while improving quality of life in disadvantaged communities and producing positive externalities for society.