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Long-Term Drought Impacts
Land subsidence is a gradual settling or sudden sinking of the Earth's surface owing to subsurface movement of earth materials. Excessive groundwater pumping and aquifer depletion can cause land to sink, which can cause permanent loss of groundwater storage in the aquifer system and infrastructure damage. Overpumping in California's San Joaquin Valley aquifer system has caused renewed land-surface elevation drop that could result in serious operational and structural issues for the Delta-Mendota Canal (DMC).
In coastal communities, the reversal of natural groundwater flows to the ocean as a result of groundwater pumping can cause seawater to enter the aquifer system. Seawater intrusion compromises groundwater quality and can be a costly problem to manage. The City of Santa Barbara is working with the California Water Science Center to update information on its groundwater supplies and to identify optimal water-resource management strategies to balance groundwater use with other sources of water.
Water allocations for river, wetland, wildlife, and fish restoration projects can be reduced or stopped altogether during severe drought. The California Water Science Center is part of the team tasked to restore river flows for salmon survival along the San Joaquin River. This year the Bureau of Reclamation will reduce flows a month earlier than planned because of critical water shortages.
Dry, hot and windy weather, combined with dry vegetation and a spark - either through human intent, accident or lightning - can start a wildfire. Drier-than-normal conditions can increase the intensity and severity of wildfires. In the aftermath of wildfires such as the 2013 Rim Fire, ash, woody debris and sediment can flow downstream from burn areas and contaminate water supplies. Flash flooding and mudslides in burn areas can also be damaging and deadly.
USGS science - conducted both in "real-time" and over the long-term - helps inform decision makers in communities across the country who have to deal complex issues and competing interests in times of drought. The California Water Science Center monitors the immediate impacts of drought on water availability and water quality through streamflow, surface water, and groundwater monitoring and data collection. Long-term data collection is needed to asses the effects of climate variability on water sources, to monitor the effects of regional aquifer development, and to obtain data sufficient for analysis of surface water and groundwater-level trends.
http://ca.water.usgs.gov/data/drought/drought-impact.html
"Because of increased pumping, groundwater levels are reaching record lows — up to 100 feet (30 meters) lower than previous records," Mark Cowin, director
of California's Department of Water Resources, said in a statement. "As extensive groundwater pumping continues, the land is sinking more rapidly, and this puts nearby infrastructure at greater risk of costly damage." [It's Raining Spiders! The Weirdest Effects of California's Drought]
What's more, this furious groundwater pumping could have long-term consequences. If the land shrinks too much, and for too long, it can permanently lose its ability to store groundwater, the researchers said.
Certain hotspots are shrinking at an astonishing rate — regions of the Tulare Basin, which includes Fresno, sank 13 inches (33 cm) in just eight months, they found. The Sacramento Valley is sinking about 0.5 inches (1.3 cm) per month. And the California Aqueduct — an intricate network of pipes, canals and tunnels that funnels water from high in the Sierra Nevada mountains in northern and central California to Southern California — has sunk 12.5 inches (32 cm), and most of that was just in the past four months, according to the new study.
The unquenchable thirst for groundwater in certain regions is largely a result
of agriculture: Most of the state's agricultural production resides in the fast-sinking regions around some of the state's most endangered river systems — the San Joaquin and Sacramento rivers. As the heat and lack of rainfall have depleted surface-water supplies, farmers have turned to groundwater to keep their crops afloat.
Subsidence isn't just an aesthetic problem; bridges and highways can sink and crack in dangerous ways, and flood-control structures can be compromised. In the San Joaquin Valley, the sinking Earth has destroyed the outer shell around thousands of privately drilled wells.
"Groundwater acts as a savings account to provide supplies during drought, but the NASA report shows the consequences of excessive withdrawals as we head into the fifth year of historic drought," Corwin said. "We will work together with counties, local water districts, and affected communities to identify ways to slow the rate of subsidence and protect vital infrastructure
such as canals, pumping stations, bridges and wells."
http://www.livescience.com/51943-california-sinking-faster-than-thought.html
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Land subsidence is a gradual settling or sudden sinking of the Earth's surface owing to subsurface movement of earth materials. Excessive groundwater pumping and aquifer depletion can cause land to sink, which can cause permanent loss of groundwater storage in the aquifer system and infrastructure damage. Overpumping in California's San Joaquin Valley aquifer system has caused renewed land-surface elevation drop that could result in serious operational and structural issues for the Delta-Mendota Canal (DMC).
In coastal communities, the reversal of natural groundwater flows to the ocean as a result of groundwater pumping can cause seawater to enter the aquifer system. Seawater intrusion compromises groundwater quality and can be a costly problem to manage. The City of Santa Barbara is working with the California Water Science Center to update information on its groundwater supplies and to identify optimal water-resource management strategies to balance groundwater use with other sources of water.
Water allocations for river, wetland, wildlife, and fish restoration projects can be reduced or stopped altogether during severe drought. The California Water Science Center is part of the team tasked to restore river flows for salmon survival along the San Joaquin River. This year the Bureau of Reclamation will reduce flows a month earlier than planned because of critical water shortages.
Dry, hot and windy weather, combined with dry vegetation and a spark - either through human intent, accident or lightning - can start a wildfire. Drier-than-normal conditions can increase the intensity and severity of wildfires. In the aftermath of wildfires such as the 2013 Rim Fire, ash, woody debris and sediment can flow downstream from burn areas and contaminate water supplies. Flash flooding and mudslides in burn areas can also be damaging and deadly.
USGS science - conducted both in "real-time" and over the long-term - helps inform decision makers in communities across the country who have to deal complex issues and competing interests in times of drought. The California Water Science Center monitors the immediate impacts of drought on water availability and water quality through streamflow, surface water, and groundwater monitoring and data collection. Long-term data collection is needed to asses the effects of climate variability on water sources, to monitor the effects of regional aquifer development, and to obtain data sufficient for analysis of surface water and groundwater-level trends.
http://ca.water.usgs.gov/data/drought/drought-impact.html
"Because of increased pumping, groundwater levels are reaching record lows — up to 100 feet (30 meters) lower than previous records," Mark Cowin, director
What's more, this furious groundwater pumping could have long-term consequences. If the land shrinks too much, and for too long, it can permanently lose its ability to store groundwater, the researchers said.
Certain hotspots are shrinking at an astonishing rate — regions of the Tulare Basin, which includes Fresno, sank 13 inches (33 cm) in just eight months, they found. The Sacramento Valley is sinking about 0.5 inches (1.3 cm) per month. And the California Aqueduct — an intricate network of pipes, canals and tunnels that funnels water from high in the Sierra Nevada mountains in northern and central California to Southern California — has sunk 12.5 inches (32 cm), and most of that was just in the past four months, according to the new study.
The unquenchable thirst for groundwater in certain regions is largely a result
Subsidence isn't just an aesthetic problem; bridges and highways can sink and crack in dangerous ways, and flood-control structures can be compromised. In the San Joaquin Valley, the sinking Earth has destroyed the outer shell around thousands of privately drilled wells.
"Groundwater acts as a savings account to provide supplies during drought, but the NASA report shows the consequences of excessive withdrawals as we head into the fifth year of historic drought," Corwin said. "We will work together with counties, local water districts, and affected communities to identify ways to slow the rate of subsidence and protect vital infrastructure
http://www.livescience.com/51943-california-sinking-faster-than-thought.html
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