Global water resources and the role of groundwater in a resilient water future

Nature Portfolio (Springer Nature) | January 31st, 2023

Water is a critical resource, but ensuring its availability faces challenges from climate extremes and human intervention. In this Review, we evaluate the current and his

Water is a critical resource, but ensuring its availability faces challenges from climate extremes and human intervention. In this Review, we evaluate the current and historical evolution of water resources, considering surface water and groundwater as a single, interconnected resource. Total water storage trends have varied across regions over the past century. Satellite data from the Gravity Recovery and Climate Experiment (GRACE) show declining, stable and rising trends in total water storage over the past two decades in various regions globally. Groundwater monitoring provides longer-term context over the past century, showing rising water storage in northwest India, central Pakistan and the northwest United States, and declining water storage in the US High Plains and Central Valley. Climate variability causes some changes in water storage, but human intervention, particularly irrigation, is a major driver. Water-resource resilience can be increased by diversifying management strategies. These approaches include green solutions, such as forest and wetland preservation, and grey solutions, such as increasing supplies (desalination, wastewater reuse), enhancing storage in surface reservoirs and depleted aquifers, and transporting water. A diverse portfolio of these solutions, in tandem with managing groundwater and surface water as a single resource, can address human and ecosystem needs while building a resilient water system.

Glossary of Selected Terms Useful in Studies of the Mechanics of Aquifer Systems and Land Subsidence due to Fluid Withdrawal

U.S. Geological Survey (USGS) | January 1st, 1972

The geologic and engineering literature contains a variety of terms that have been used to describe the processes and environmental conditions involved in the mechanics o

The geologic and engineering literature contains a variety of terms that have been used to describe the processes and environmental conditions involved in the mechanics of stressed aquifer systems and of land subsidence due to withdrawal of subsurface fluids. The usage of certain of these terms in reports by the U.S. Geological Survey research staff investigating mechanics of aquifer systems and land subsidence is defined and explained in this glossary. Several terms that have developed as a result of the Survey's investigations are also defined.

Goal-based water trading expands and diversifies supplies for enhanced resilience

Nature Portfolio (Springer Nature) | February 11th, 2019

In response to rising water scarcity concerns around the world, water utilities are expanding and diversifying their water supply portfolios, including attempting to valu

In response to rising water scarcity concerns around the world, water utilities are expanding and diversifying their water supply portfolios, including attempting to value and reuse every drop throughout the water cycle. This transition is creating new hybrid infrastructure systems that combine centralized and decentralized sources at various scales. To help strategize and manage these emerging hybrid systems, we introduce a flexible goal-based water-trading framework using a combination of regulatory and market incentives. We apply this framework in a simulation of the San Francisco Bay Area, and test the effects of policy parameters, local preferences and collaboration between utilities. Results show that the option of engaging in an open trading scheme can lead to a more strategic and holistic path to higher regional resiliency through increased diversity in water portfolios, at lower costs than if utilities were tasked with pursuing goals independently. Highest benefits are observed when utilities cooperate in the exchange of information, which highlights the importance of transparency and trust operating in conjunction with regulatory and market forces.

Goal-based water trading expands and diversifies supplies for enhanced resilience

Nature Portfolio (Springer Nature) | February 11th, 2019

In response to rising water scarcity concerns around the world, water utilities are expanding and diversifying their water supply portfolios, including attempting to valu

In response to rising water scarcity concerns around the world, water utilities are expanding and diversifying their water supply portfolios, including attempting to value and reuse every drop throughout the water cycle. This transition is creating new hybrid infrastructure systems that combine centralized and decentralized sources at various scales. To help strategize and manage these emerging hybrid systems, we introduce a flexible goal-based water-trading framework using a combination of regulatory and market incentives. We apply this framework in a simulation of the San Francisco Bay Area, and test the effects of policy parameters, local preferences and collaboration between utilities. Results show that the option of engaging in an open trading scheme can lead to a more strategic and holistic path to higher regional resiliency through increased diversity in water portfolios, at lower costs than if utilities were tasked with pursuing goals independently. Highest benefits are observed when utilities cooperate in the exchange of information, which highlights the importance of transparency and trust operating in conjunction with regulatory and market forces.

Going Beyond Low Flows: Streamflow Drought Deficit and Duration Illuminate Distinct Spatiotemporal Drought Patterns and Trends in the U.S. During the Last Century

American Geophysical Union (AGU) | August 30th, 2022

Streamflow drought is a recurring challenge, and understanding spatiotemporal patterns of past droughts is needed to manage future water resources. We examined regional p

Streamflow drought is a recurring challenge, and understanding spatiotemporal patterns of past droughts is needed to manage future water resources. We examined regional patterns in streamflow drought metrics and compared these metrics to low flow timing and magnitude using long-term daily records for 555 minimally disturbed watersheds. For each streamgage, we calculated streamflow drought duration (number of days) and deficit (flow volume below a specified threshold) for each climate year (April 1–March 31). We identified drought using five thresholds (2%–30%) and two approaches: variable thresholds with unique values for each day of the year, and a fixed threshold based on all period-of-record flows. We then analyzed drought trends using the Mann-Kendall test with persistence adjustment for 1921–2020, 1951–2020, and 1981–2020, and computed correlations between annual streamflow drought metrics and climate metrics using values from a monthly water balance model. Spatial patterns in drought metrics were consistent between variable and fixed approaches, though fixed threshold durations were typically longer and variable threshold deficits larger. High interannual variability in drought duration emerged in the central, interior west, and southwestern U.S., with high deficit variability in the interior west. Drought metrics were weakly correlated with low flow magnitude and timing, providing unique information. Drought duration and deficit increased in the southern and western U.S. for both 1951–2020 and 1981–2020, particularly using fixed thresholds, and paralleled trends in aridity. Projections of continued aridification for the southern and western U.S. may increase drought durations and deficits and intensify water availability impacts.

Gold Extraction Processes

Scientific American | October 31st, 1896

FROM very early times the ancients were attracted the beautiful color, the brilliant luster and the indestructibility of gold, and spared no pains in the endeavor to acqu

FROM very early times the ancients were attracted the beautiful color, the brilliant luster and the indestructibility of gold, and spared no pains in the endeavor to acquire it. In the code of Menes, who reigned in Egypt some 2,000 years before the time of Moses, the ratio of value between gold and silver is mentioned, one part of gold being declared equal in value to two and a half parts of silver, and it is, therefore, clear that the extraction of both metals from the deposits containing them must have been carried on before that time. It is indeed probable that gold was the first metal observed and collected, since it occurs in fragments of all sizes in loose sand, and the operations of collecting the larger pieces and melting them together are so simple. Among the rock carvings of Upper Egypt there are several illustrative of the art of washing auriferous sands by stirring and working them up by the hand in hollowed-out stone basins, and subsequently melting the gold in simple furnaces with the aid of mouth blowpipes. The earliest of these carvings is supposed to date back to about 2,500 B.C. However, in ancient times, gold appears to have been mainly derived from India, and that country continued to supply most of the gold used in Europe until the discovery of America by Columbus.

Gone with the flow

Bay Institute | August 1st, 2010

The Bay Institute's primer Gone with the Flow describes in plain language how runoff flowing from the mountain watersheds ringing California’s Central Valley provided c

The Bay Institute's primer Gone with the Flow describes in plain language how runoff flowing from the mountain watersheds ringing California’s Central Valley provided coldwater paradises for salmon returning to their native streams; turned lowland rivers and their floodplains into a rich source of food and shelter for young fish; mingled in the Delta’s complex maze of marshes and sloughs; and created a vast expanse of brackish water habitat essential for estuarine creatures in the upper reaches of San Francisco Bay. The primer also explains how the lack of access to most upland streams now forces migratory fish to cope with undesirable, often lethal flow conditions; how runoff in lowland rivers has been shifted from spring to summer, or even almost completely cut off in the San Joaquin basin, with disastrous consequences for the environment; how reverse flows in Delta channels kill hundreds of millions of aquatic organisms each year; and how the Bay is now in a permanent ecological drought because of the diversion of half its freshwater inflow.

Gone. Decades of greed, neglect, corruption, and bad politics led to last year’s Paradise fire, the worst in California history. It should never have happened. It will happen again.

California Sunday Magazine | July 31st, 2019

By the time I made it to Paradise, the deadliest wildfire in California history was four months past, and the burned-out ridge between the two river canyons was pouring

By the time I made it to Paradise, the deadliest wildfire in California history was four months past, and the burned-out ridge between the two river canyons was pouring rain. I was riding the Skyway, the road from Chico to Paradise, flatland to hilltop, trying to understand what forces had conspired last November to create a blaze of such anger that it took the lives of 85 people and destroyed 19,000 structures. I had puzzled out enough disasters to know that tragedy was a force of intricate construction. It wasn’t one detached act that materialized as tragedy but myriad smaller acts — some incidental, some accidental, others malevolent — that lined up in perfect continuity. Had one circumstance in the sequence lost its footing, a cosmic stumble, the next circumstance would have never hitched on, and tragedy would have been averted.

Good Samaritan Remediation of Abandoned Hardrock Mines Act of 2024

U.S. Government Publishing Office (GPO) | December 17th, 2024

To promote remediation of abandoned hardrock mines.

To promote remediation of abandoned hardrock mines.

Goodbye to “Rough Fish”: Paradigm Shift in the Conservation of Native Fishes

American Fisheries Society (AFS) | July 21st, 2021