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Water availability and use in the Colorado River basin Over the past century, consumptive water uses in the basin increased steadily, to the point that annual consumption exceeded total river flows in 75% of years from 2000–2015. This over consumption has dried the river at its delta in Mexico and progressively depleted major storage reservoirs in the basin, including Lake Mead, posing severe risk of water shortage. All variables are portrayed as three-year running averages. Data source: US Bureau of Reclamation.
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Human consumption of freshwater is now approaching or surpassing the rate at which water sources are being naturally replenished in many regions, creating water shortage risks for people and ecosystems. Here we assess the impact of human water uses and their connection to water scarcity and ecological damage across the United States, identify prima...
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As part of the circular economy, there is increasing interest internationally in water reuse, reclaimed water or recycled wastewater. This interest responds to water scarcity concerns at present and to demands projected for the resource by all sectors in the future, which will surpass freshwater available. It also responds to the incentive to close...
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... Our modeling effort builds upon the national WaSSI modeling effort described in Richter et al. (2020), which simulated river flow depletion for the 2000-2015 period. Because input data for Mexico had not been used in this previous WaSSI modeling effort, additional data on climate, topography, soils, and water use in Mexico needed to be acquired from other sources. ...
The Rio Grande-Rio Bravo's flow regime has been highly altered for more than 130 years, yet the river ecosystem still supports important biodiversity including numerous endangered species. More than 80% of water consumed in the basin goes to irrigating farms, but in recent decades, farmers have repeatedly experienced severe water shortages. Given this water-scarce condition, any plans for enhancing environmental flows must be carefully designed to minimize impacts or provide benefits to agriculture. This study describes the development of the Rio Grande-Rio Bravo's first whole-basin hydrologic model-representing both the United States and Mexico portions of the basin-to enable exploration of environmental flow restoration needs and options for meeting these needs. We then demonstrate an analytical process in which environmental flow needs are compared to existing flow conditions to quantify gaps, and then evaluate how those gaps can be filled by reducing farm irrigation needs by shifting to less water-intensive crops and fallowing a portion of existing farmland while maintaining or improving net revenues. In our pilot assessment we find that an improvement of 2.2 m3/s would fill the environmental flow gap for late-summer low-flow conditions at Albuquerque, New Mexico. This flow enhancement is attainable by fallowing 18%-26% of cropland and shifting to more profitable and less water-intensive crops to sustain overall farm revenues.
... We built on the work of Richter et al. 3 by extending the hydrological simulation period from 1981 to 2019 and integrating new detailed monthly estimates of irrigation use for 30 individual crops (accounting for 94% of the total irrigated area and 95% of irrigation water consumption in the United States, Supplementary Table 1). We estimated monthly hydrological balances using the water supply stress index (WaSSI) ecosystem services model, which can simulate the hydrological impact of extractions from surface water and groundwater sources separately as well as hydrological interactions between river flow and groundwater 31,32 . ...
... We estimated monthly hydrological balances using the water supply stress index (WaSSI) ecosystem services model, which can simulate the hydrological impact of extractions from surface water and groundwater sources separately as well as hydrological interactions between river flow and groundwater 31,32 . Richter et al. 3 used static irrigation requirements based on annual average crop water requirements from 1996 to 2005. We have improved upon this approach by estimating crop water requirements at a monthly time step for each month from 1981 to 2019, which allowed us to capture the seasonal and interannual variability of crop water use, facilitating our assessment of trends and changing crop mixes over time. ...
... There are 2,099 HUC8 sub-basins in the conterminous United States, each with a mean area of 3,750 km 2 . All WaSSI input data and assumptions used in this study are exactly as described by Richter et al. 3 , but we included updated climate and land use data for an extended period of 1981-2019, as described below, and used substantially improved estimates of crop water consumption, also described below. An important feature of our hydrological model is the tracking of surface water flows from upstream to downstream sub-basins within each drainage network. ...
Irrigated agriculture dominates freshwater consumption globally, but crop production and farm revenues suffer when water supplies are insufficient to meet irrigation needs. In the United States, the mismatch between irrigation demand and freshwater availability has been exacerbated in recent decades due to recurrent droughts, climate change and overextraction that dries rivers and depletes aquifers. Yet, there has been no spatially detailed assessment of the potential for shifting to new crop mixes to reduce crop water demands and alleviate water shortage risks. In this study, we combined modelled crop water requirements and detailed agricultural statistics within a national hydrological model to quantify sub-basin-level river depletion, finding high-to-severe levels of irrigation scarcity in 30% of sub-basins in the western United States, with cattle-feed crops—alfalfa and other hay—being the largest water consumers in 57% of the region’s sub-basins. We also assessed recent trends in irrigation water consumption, crop production and revenue generation in six high-profile farming areas and found that in recent decades, water consumption has decreased in four of our study areas—a result of a reduction in the irrigated area and shifts in the production of the most water-consumptive crops—even while farm revenues increased. To examine the opportunities for crop shifting and fallowing to realize further reductions in water consumption, we performed optimizations on realistic scenarios for modifying crop mixes while sustaining or improving net farm profits, finding that additional water savings of 28–57% are possible across our study areas. These findings demonstrate strong opportunities for economic, food security and environmental co-benefits in irrigated agriculture and provide both hope and direction to regions struggling with water scarcity around the world.
... The TI data was derived from high-resolution global data [44]. The amount of surface or groundwater inputs that can impact on wetland distributions [45]. In this paper we use Euclidean distance to calculate surface drainage distance. ...
Wetlands serve a critical function in water storage and ecological diversity maintenance. However, human activities have resulted in wetland loss in the middle and lower reaches of the Yangtze River Basin (MLYRB), while the wetland distribution in this area shows great discrepancy in previous estimates. It is, therefore, imperative to estimate the distribution of potential wetlands at present and project their variation under future climate change scenarios. In this study, we simulate the wetland distribution in the MLYRB at 15″ resolution using 5 machine learning methods with 19 predicting factors of topographic index, vegetation index, climate data, hydrological data, and soil type data. A 5-fold cross-validation with observed permanent wetlands shows that the reconstructions from Adaptive Boosting tree (AdaBoost) algorithm have the highest accuracy of 97.5%. The potential wetland area in the MLYRB is approximately ~1.25 × 105 km2, accounting for 15.66% of the study region. Direct human activities have led to the loss of nearly half of the potential wetlands. Furthermore, sensitivity experiments with the well-trained models are performed to quantify the response of the total wetland area to each influencing factor. Results indicate vulnerability of wetland areas to increases in leaf area index (LAI), coldest season temperature, warmest season temperature, and solar radiation. By the 2100s, the potential wetland area is expected to decrease by 40.5% and 50.6% under the intermediate and very high emissions scenarios, respectively. The changes in LAI and the coldest season temperature will contribute to 50% and 40% of this loss of potential wetlands, respectively. Wetland loss may further undermine biodiversity, such as waterfowl, and fail to provide functions such as flood protection, and water supply. This work reveals the spatial pattern of potential wetland areas and their sensitivity to climate changes, stressing the need for effective strategies to mitigate wetland loss at specific regions in the MLYRB.
... threats to human survival and the health of terrestrial and aquatic ecosystems [3][4][5][6]. In addition, urbanization, industrial development, and excessive use of pesticides have severely disrupted the natural equilibrium of the water ecosystem [7-9], thereby accelerating the depletion of available freshwater resources and promoting deterioration of water quality. ...
Access to clean and equitable water is vital to human survival and an essential component of a sustainable society. Using 59 monitoring sections, the water quality of 32 rivers in 12 river systems within two river basins in one resource-depleted city (Jiaozuo) was examined in four seasons to better comprehend the extent of river pollution, and the distribution prediction of main indexes was conducted. In total, 92% of the monitoring sections met the national standards. Overall, 12.5%, 62.5%, and 25% of samples met water quality standards III, IV, and V, respectively. The concentrations of total nitrogen (TN), total phosphorus (TP), and chemical oxygen demand (COD) ranged from 0.527 to 7.078, 0.001 to 1.789, and 0.53 to 799.25 mg/L, respectively. The Yellow River Basin has higher annual mean concentrations of total carbon (TC), TN, and total organic carbon (TOC) than the Haihe River Basin. The highest and lowest concentrations of specific water quality indices varied across seasons and rivers. Dashilao and Rongyou Rivers have the best water quality, while Dasha, Xin, and Mang Rivers have the worst. TN, TP, and NH4+-N concentrations in the Laomang River midstream were greater than those upstream and downstream. Statistically, significant positive associations were found between NH4+-N and TC, TOC, and COD (p < 0.025), where NH4+-N and COD influenced water quality the most. A significant positive relationship between COD and TP (p < 0.01) was observed. Overall, water quality values were highest in the summer and lowest in winter. The distribution prediction revealed TN, TP, NH4+-N, and COD showed significant regional differences. Household sewage, industrial sewage discharge, and agricultural contamination were all the possible significant contributors to declining water quality. These findings could provide a scientific reference for river water resource management in resource-depleted cities.
... Across the United States, cities with high SCD values were less likely to experience food shocks of increasing intensity than cities with low SCD values ( Supplementary Fig. 2). While the exposure of cities' food supply chains to water stress did not vary considerably between food sectors, it did reveal a marked spatial pattern, characterized by cities in the west being more exposed to water stress than those in the east through food ows 30,31 (Supplementary Fig. 3). On average, across food sectors, the SCE of western cities was 0.50 versus 0.19 in eastern cities (p < 0.001). ...
Global warming is exacerbating agricultural production losses from extreme climate events, with cascading impacts along supply chains that affect cities. However, little is known about cities’ vulnerability to climate-related food supply shocks. Here, using data-driven and network-based approaches, we determine the vulnerability of cities in the United States to domestic drought-related food shocks. Our vulnerability framework integrates key traits—resilience, exposure, and sensitivity to disruption—of a social-ecological system’s response to hazard. We find that vulnerability varies considerably across cities. It tends to be high for western cities because of both high supply chain exposure to water stress and high urban food insecurity. Using the 2012–2013 U.S. drought as a case study, we show that high-vulnerability cities are associated with more extreme food shocks and greater food supply losses than low-vulnerability cities. Our vulnerability framework can help inform climate adaptation interventions for food system security in urban-rural interactions.
... foods (including commercial fishing) is likely the leading cause of modern species extinctions (Steinfeld et al., 2006;Machovina et al., 2015;Díaz et al., 2019). In Central US (and other hotspots in China and India), the planetary boundary for freshwater use has been exceeded already due to livestock (Leng and Hall, 2021; see also, Richter et al., 2020;Mekonnen and Hoekstra, 2012). But, despite the large environmental costs of animal-based foods, governments have done little if nothing to address this issue. ...
Building on literature from political science and psychology, I argue that political attention on animals and animal-friendly political candidates cause voter backlash. I test this using two different kinds of experiments with large, representative samples. I ask respondents to consider political candidates running for office in a U.S. presidential primary context. I find that, overall, political attention on the need to reduce meat consumption for environmental reasons caused voter backlash compared to both a control condition and attention on the need to reduce reliance on gasoline-powered vehicles (also for environmental reasons). But, the heterogeneous effects of partisan identification were strong: voter backlash was mainly driven by Republicans and Democrats were neutral. Surprisingly, candidates who put attention on farm animal rights during elections faced no voter backlash from Republicans or Democrats. Animal-friendly candidates, particularly Black women and Latinas, with attributes that demonstrate personal concern for farm animals and strong support for animal rights generally fared very well in elections, receiving large boosts in voter support. This work launches a research agenda in political psychology that “brings the animal in” to politics.
... Consideration might also be given to identifying which irrigated crops in which regions provide the highest economic return or are most important to meeting national food needs. Alfalfa and pasture grasses, used as livestock feed, are the primary crop in much of the Basin, and use of large amounts of water for this purpose has been questioned (Richter et al., 2020). ...
During much of the 21st century, natural runoff in the Colorado River basin has declined, while consumption has remained relatively constant, leading to historically low reservoir storage. Between January 2000 and April 2023, the amount of water stored in Lake Mead and Lake Powell, the two largest reservoirs in the United States, declined by 33.5 million acre feet (41.3 billion cubic meters). As of April 2023, total basin‐wide storage was sufficient to support the 21st century average rate of basin‐wide consumption for only 15 months. Runoff in spring 2023 is predicted to be large, providing a short‐term reprieve. However, it will take four to five additional unusually wet years in succession to refill Lake Powell and Lake Mead if basin‐wide water use remains unchanged. Increasing evapotranspiration and dry soils associated with global climate change makes such a scenario unlikely. To stabilize reservoir storage, basin‐wide use needs to equal modern runoff. To recover reservoir storage, basin‐wide use needs to decline even more. Based on 21st century average runoff, a 13%–20% decline in basin‐wide use would allow for stabilization and some reservoir storage recovery. Future policy debate about reservoir operations will inevitably concern whether most, or all, reservoir storage should be in Lake Mead or in Lake Powell. The choice of one or the other will result in significantly different environmental and recreational outcomes for Glen Canyon and the Grand Canyon.
This article is categorized under: Water and Life > Stresses and Pressures on Ecosystems
Human Water > Water Governance
Science of Water > Water and Environmental Change
... Reducing and/or fallowing summer-irrigated cropland currently dedicated the production of livestock feed to reduce irrigation demand is of increasing interest in much of the Western US (Richter et al., 2020). This highlights a niche of growing importance where winter forage production might compensate for reduced feed availability while reducing net water use through a combination of winter precipitation and small amounts of irrigation. ...
CONTEXT: Efforts to achieve groundwater sustainability in California’s San Joaquin Valley will entail substantial pumping reductions, and much irrigated cropland may become newly fallowed. Winter crops grown under water- limited conditions could offer an alternative to fallowing, but their viability may be limited by variable rainfall and high crop failure rates. OBJECTIVE: The first objective of this study was to evaluate how small (100–200 mm), targeted irrigation events impact crop establishment, forage and grain yields, and the resulting economic and agronomic water productivity of winter wheat at 4 sites in the San Joaquin Valley. Additionally, we assessed the probability of producing economically viable forage yields across the region based on historical precipitation totals combined with 0, 100, or 200 mm of supplemental irrigation. METHODS: We used APSIM to run 20-yr simulations of winter wheat establishment and productivity under historical weather conditions at four groundwater dependent sites in California’s San Joaquin Valley. For each site, we simulated wheat productivity (biomass and grain) under three irrigation scenarios (no irrigation, 100 mm, or 200 mm) and three sowing dates (mid-October, mid-November, and mid-December). We applied model outputs to calculations of economic and agronomic water productivity, and used the modeled relationship between soft dough biomass yield and total water input (precipitation plus irrigation) to determine the likelihood of a successful wheat crop in any given year across the region.
... The shortage of freshwater has become one of the most crucial global challenges in society [1,2]. To address this issue, various separation techniques, such as membrane or distillation processes and reverse osmosis technologies, have been implemented to purify water at an industrial scale [3][4][5]. ...
Currently, freshwater scarcity is a global challenge, and developing low-cost methods for purifying, desalinating, and distilling seawater is crucial. Natural wood, owing to its advantages of high hydrophilicity, low density, microporous channels, and low thermal conductivity, is widely considered a vehicle for solar evaporation. However, the majority of the reported wood-based solar evaporation generators have been economically inefficient, with limited evaporation rates under low-power solar irradiation. Herein, we developed an ecofriendly and efficient wood-based solar evaporation generator comprising a material with excellent photothermal conversion efficiency, polyoxovanadate, loaded on the wood surface with a natural channel structure. The solar evaporation generator exhibited high light absorption capacity (∼98%) in the wide wavelength range of 200–1200 nm, rapid water transport through the wood channels, minimal heat dissipation due to the adiabaticity of the wood, and reduced evaporation enthalpy. Therefore, the overall evaporation efficiency was increased, and a high evaporation rate of 2.23 kg m−2 h−1 and solar-vapor efficiency of 90% under 1 Sun was observed. This environment-friendly, low-cost, and high-efficiency evaporation generator has enormous potential for practical applications in solar desalination and water purification.
... The WaSSI model was developed by the United States Forest Service (USFS) to represent the impact of human influences (e.g., land cover change, water withdrawals, climate change) on monthly hydrologic processes and water supplies at the HUC 8 scale across the United States. The validated model has been extensively used for both governmental and research purposes (Caldwell et al., 2012;Eldardiry & Habib, 2018;Marston et al., 2020;Richter et al., 2020;Sun et al., 2008). Here, we run the model for 2011-2015 and we use the average annual streamflow and water withdrawals to estimate the Water Supply Stress Index-that is, the ratio of total water withdrawals within a watershed to total available water supplies-for each HUC 4 watershed. ...
The production of food, electricity, and treated water is often tracked and managed along political or infrastructure boundaries. Yet, water resources, a critical input in the production of these goods, are delineated along natural landscape features (i.e., watersheds). The boundary mismatch between water resources and the associated production of economic goods conceals hydrologic dependencies and vulnerabilities in the provisioning of Food‐Energy‐Water (FEW) resources. In this study, we pair economic, infrastructure, and hydrologic data to evaluate the production of food, electricity, and treated water within watersheds of the conterminous United States. The US FEW sectors produced 950 million tonnes of crops, 3,973 million MWh of electricity, and supplied water to 263 million people in 2017. FEW production consumed 128 km³ of blue water (18%) and 583 km³ of green water (82%). Watersheds in central and southern California, the Midwest, and the Southwest have the largest FEW blue water consumption and the greatest exposure to water stress. Nearly three‐fifths of FEW production occurs in regularly water‐stressed watersheds. FEW production in watersheds in the Great Plains and Midwest relies heavily on groundwater to buffer against intra‐ and inter‐annual streamflow variability, while surface reservoir storage buffers against water shortages in all watersheds. We show where FEW production may be susceptible to curtailments due to ongoing groundwater depletion or known infrastructure deficiencies. This study adds to our understanding of how a nation's water resources and associated infrastructure support economic activity, as well as areas where economic activity is exposed to hydrological and infrastructure risks.
