Posts Tagged: recharge
Regents question who should pay
This week was the Regent's meeting where UC ANR had a chance to educate the Regents about who we...
Busy meeting and learning
Last week it rained in southern California. And no one warned me. Despite that, it was a productive...
Extreme Precipitation and Water Storage in California
Reposted from the California Institute for Water Resources Blog
California's recent drought was the worst in memory. However, in a relatively quick turnaround, this year the state's water infrastructure is full and water managers are battling the wettest winter on record in quite some time. Now, by many accounts, the drought is over for much of the state.
The uniquely wet winter of 2016-2017 has highlighted a key issue surrounding our surface and ground water storage infrastructure: We could have stored this abundant water, not in new reservoirs, but right under our feet. The cycles of drought and flood will continue in California; in order to survive the droughts we have to move winter precipitation to groundwater storage in greater quantity and more efficiently.
Just as spring is showing bluer skies, and we have a handle on local flooding, there's yet more water to come from the mountains. After five years of thin and, in some cases, non-existent snow cover, the California Department of Water Resources snow survey data shows nearly 47 inches of snow water equivalent. That is, there's nearly four feet of water sitting on top of the Sierras ready to melt and fill our rivers, reservoirs, floodplains, and where possible, percolate into underground aquifers.
At the beginning of the calendar year, as heavy precipitation continued, reservoir managers started holding back and reserving water behind dams, uncertain how much precipitation we might get through the rest of the rainy season. But the heavy rain and snow turned out to be overwhelming, and reservoirs were near capacity by mid-February, losing the ability to further store runoff and mitigate for floods. In other words, there is a limit to how much water we can store behind these dams.
On the other hand, the amount of groundwater storage potential (between 850-1300 million acre feet) in California dwarfs our current surface water storage capacity (42 million acre feet). Unfortunately, with some inspiring exceptions, California does not typically manage or store surface water and groundwater conjunctively. But with patterns like a long drought followed by an extremely wet winter, we have the opportunity to prepare groundwater storage infrastructure that will help us to take excess surface water and store it in aquifers.
With Sierra Nevada sensor networks and remote sensing, we can account for how much water is available in snow, how much water should be stored as groundwater, and how much can be safely stored in reservoirs. With sites like the Southern Sierra Critical Zone Observatory on the Kings River and San Joaquin River watershed, and its expansion to UC Water'sAmerican River Hydrological Observatory, we can measure in near-real-time how much water is in the Sierra Nevada and model the timing of its arrival to streams and reservoirs.
This year we largely missed the groundwater storage opportunity, especially for basins battling with overdraft issues. If we focus on groundwater storage potential now, we could be ready for the next very wet winter when it comes.
Dr. Safeeq is a Research Scientist with Sierra Nevada Research Institute, University of California, Merced and Investigator with the UC Water Security and Sustainability Research Initiative. Follow him on Twitter @safeeqkhan @ucwater, and keep up to date with California's weather patterns through a free service, the California Climate Tracker.
Groundwater banking captures the media's imagination
The article included a map of California with color coded areas indicating areas that were excellent for groundwater banking down to poor. The story was picked up widely by the news media.
California farmers will intentionally flood their fields this winter
Jane Braxton Little, Scientific American
For two months this winter, a team of scientists will flood almond orchards in the Central Valley to a depth of two feet by redirecting rainfall through a network of ditches originally designed to divert floodwater away. To measure success, they will then monitor how much water filters into the water table over the course of two years. If the method pans out, pear, plum and walnut tree orchards might also benefit from intentional flooding, according to a recent study led by UC ANR Cooperative Extension specialist Anthony O'Geen.
Map identifies farmland with greatest potential for groundwater recharge
Diane Nelson, UC Davis News Service
This December, O'Geen and a team of scientists - including Helen Dahlke, professor in integrated hydrologic sciences at UC Davis - will flood almond fields in the Central Valley, building on research that suggests that deliberately flooding farmland in winter can replenish aquifers without harming crops or drinking water. “Adding an extra few feet of water to even just 10 percent of California's cropland this winter could add an additional 3 million acre-feet of groundwater,” Dahlke said. “That could go a long way toward replenishing the 6 million acre-feet growers had to pump this year alone to cope with California's drought.”
UC scientists test inexpensive way to capture El Niño rains
Amy Graff, The San Francisco Chronicle (SFGate.com)
Researchers from UC Davis and UC Cooperative Extension are testing a new method for capturing some of that underutilized water by diverting it from rivers into the network of canals running through Central Valley farmland. "That could go a long way toward replenishing the 6 million acre-feet growers had to pump this year alone to cope with California's drought," said Dahlke, who's testing the technique in the field. UC ANR Cooperative Extension specialist O'Geen points out that this is a win-win for agriculture. "They're typically considered the bad guys. They're feeding the world yet they're considered the water hogs because they have to take all the water to grow the food. On-farm recharge offers the opportunity for them to offer two services — providing food and collecting water. That puts agriculture in a better light."
How California could get smarter about droughts and flooding
Nathaneal Johnson, Grist.org
Land suitable for flooding should be flat, free of contamination and clear of structures. O'Geen estimates that leaves 3.6 million acres. “A preliminary calculation based only on soil properties and crop type shows that landscapes rated Excellent or Good could be used to bank as much as 1.2 million acre feet of water per day.” UC ANR groundwater hydrologist Thomas Harter was also a source in the article. He said there are additional challenges to overcome, including reluctant farmers, variations in soil profile, red tape and a lack of infrastructure, especially on farms that now use micro sprinklers or drip irrigation systems, rather than flood.
California farmers hope to capture El Niño rains
David Dienick, KCRA 3 News
Researchers have been looking for ways to capture more runoff without relying on reservoirs. "We've never actually managed our agriculture landscapes for groundwater recharge to my knowledge," O'Geen said.
Farmers urged to flood their fields with any upcoming rain
KFBK News Radio
A soil map has been developed that will allow farmers to take advantage of every opportunity to recharge the groundwater. "Is it a managed event where we are giving a couple extra irrigations in the winter time and the wet crops can tolerate a few extra irrigations when they don't really use the water," O'Geen said.
Another study suggests flooding farmland to recharge aquifers
Tim Hearden, Capital Press
A study in Merced, Madera and Fresno counties will determine whether diverting excess river flows from winter storms to farmland successfully. In addition, O'Geen and Dahlke plan to use some of the state's 3.6 million acres of farms and ranches with suitable topography and soil conditions to recharge aquifers during winter months. Dahlke is still conducting field experiments to evaluate how much water can be recharged in a couple of weeks.
UC maps farmland that can 'bank' groundwater during El Niño rains
KPCC 89.3
In response to California's withering drought and a dwindling water supply, researchers at UC Davis have identified farmland that could potentially "bank" groundwater during what is predicted to be an unusually wet winter. "A lot of growers are interested in learning how they can help improve the groundwater situation in California," O'Geen said. "The index provides details on the groundwater-recharge potential for any parcel, which you can search for by address or access using your device's GPS."
Ground Water Recharge Meeting Sept 29
This meeting put on by colleagues Richard Smith, Michael Cahn and Eric Brennan has been put together with the intent of helping growers, especially berry growers, retain some of the expected rainfall from this year's predicted El Niño system and gain some benefit by recharging a bit of our groundwater.
They've actually planted some cover crops out so you can see what it looks like. I'll be on hand to address management of these cover crops in strawberry.
Ground Water Recharge, Cover Crops and El Niño Preparation Field Day