Groundwater from aquifers important factor in food security

Thirsty cities, fields and livestock drink deeply from aquifers, natural sources of groundwater. But a study of three of the most-tapped aquifers in the United States shows that overdrawing from these resources could lead to difficult choices affecting not only domestic food security but also international markets.

University of Illinois professors of civil and environmental engineering Ximing Cai and Megan Konar, along with graduate student Landon Marston and Lehigh University professor Tara Troy, studied groundwater consumption from three main systems. Reliance on these aquifers intensified so much from 2000 to 2008 that it accounted for 93 percent of groundwater depletion in the U.S. They published their findings in the Proceedings of the National Academy of Sciences.

The U.S. Geological Survey identifies the Central Valley aquifer in California, the High Plains aquifer in the Great Plains states, and the Mississippi Embayment aquifer in the lower Midwest as being managed unsustainably, which means that is being extracted from the aquifer faster than it is replenishing.

"Deep groundwater is like natural gas. If you use it, it takes a while to recharge," Cai said. "Unsustainable usage means the water table is lowered, which makes it more difficult and more expensive to pump water since we have to keep going deeper. It also affects ecosystems associated with the water table, such as streams and wetlands."

The researchers tracked water consumption from the aquifers to see where the water was going, both in terms of geography and usage. For example, when water was used to irrigate a crop, the researchers tracked where those crops were shipped.

"When we think of water, we think of direct water, the water that comes out of our faucets. But we actually use a lot of embodied water in our everyday lives – the water footprint to produce a product," Konar said. "We looked at the water implicitly being transferred between states and countries in the products."

The researchers found that the vast majority – 91 percent – of embodied groundwater from these three aquifers stayed within the U.S. The remaining 9 percent was exported internationally. They identified the states most heavily reliant on each aquifer, and the breakdown of what was produced using water from each aquifer. For example, the largest percentage of water from the High Plains aquifer irrigated grains, while the largest contribution from the Central Valley aquifer in California went to producing meat. See the infographic for the detailed findings.

The researchers hope that having detailed information on how aquifer water is used, and the complex economic and environmental implications of that use, can help policy makers in their decisions about water resource management.

"The issue here is the tradeoffs. That's the difficulty for the decision makers," Cai said. "There is a tradeoff between the environment and economic profit, and there is a trade-off between the current use and future use. The environment is affected, the food markets are affected, the resources for fisheries are affected. That helps the decision makers understand the issue. I think this information is also important for the public to understand the issue."

The researchers feel that the study is also important for international leaders, as any decisions will affect global food production and prices. Although the international exports represented a small percent of the overall water consumption, the exported goods account for a large market share in the countries that import them, the study found.

Next, the researchers plan to study major watersheds in the U.S. to gain a more comprehensive picture of natural water resources in the United States. They are interested in detailing water use under variable conditions, both in terms of economic and environmental impact.

"Managing water resources for the future is especially important because future rainfall patterns are going to be more variable, with more droughts predicted," Konar said. "As we're seeing in California, they were really lucky to have aquifers to rely on during a drought. We don't want to deplete these aquifer supplies, so that when we get into these drought situations, we have some emergency backup." More

More information: "Virtual groundwater transfers from overexploited aquifers in the United States" PNAS 2015 ; published ahead of print June 29, 2015, DOI: 10.1073/pnas.1500457112

 

©

The World’s Most Hostile International Water Basins

At the launch of A New Climate for Peace, a new report on climate-fragility risks produced for the G7 by a consortium of international partners including the Wilson Center, USAID Deputy Assistant Administrator Christian Holmes called water a common denominator for climate risk.

“How you manage your water programs…has a huge amount to do with how you mitigate the prospect for increased fragility,” he said. “Sometimes it’s the obvious that’s so easy to miss, and I think that the obvious on water as it relates to economic development is, essentially, the question of sustainable water supply.”

One of the most striking infographics from A New Climate for Peace touches on that question of supply. Using data from Oregon State University’s Transboundary Freshwater Dispute Database and adapted from a graphic that originally appeared in Popular Sciencelast year, the map shows the world’s most active – and tension-filled – international water basins.

Water is a common denominator for climate risk

The Transboundary Freshwater Dispute Database measures not only the frequency of hostile events in a basin, but cooperative ones as well, each on a sliding scale. Hostile events range from declarations of war (zero recorded from 1990 to 2008, the period of time encompassed by the graphic) to leaders using “language of discord.” Cooperative events range from “mild verbal support” to “voluntary unification into a single country.”

The total number of events is indicated by shades of blue – the darker the blue, the more transboundary events, both positive and negative. This is essentially the “hot list” of international water basins – which regions have the most official and unofficial chatter over water.

Circles superimposed on the basins represent the total number of hostile events. As the description text points out, however, “circle size does not automatically translate into conflict danger.” In some places, transboundary institutions and diplomatic frameworks allow different actors to work through their differences. Cooperative hostility, if you will. In the Danube River Basin, for example, the high number of “hostile” events is mitigated by strong cooperative incentives associated with European integration. Likewise in North America, where Canada, the United States, and Mexico share several basins with a high number of hostile events, there is little chance of violent conflict.

Water basins in South Asia, the Middle East, and East Africa are major hotspots with a high number of hostile events and weaker institutional frameworks to mitigate them. The Indus, Ganges-Brahmaputra-Meghna, Salween, Tigris-Euphrates, and Jordan basins witness a very high number of interactions, suggesting at least that continued dialogue could be a way forward to mitigate the risk of violent conflict or fragility. The Nile Basin has less activity reflecting the stalled negotiations between the basin’s 10 member states to replace colonial-era water agreements. The Mekong Basin, where the largest member, China, does not participate as a full member of the Mekong River Commission, shows less activity as well.

The map does a great job illustrating why it can be difficult to answer the question, where is the highest risk of water-related violence? Tensions between states and other freshwater basin actors isn’t necessarily a sign of impending violence if there’s a framework to resolve them. Likewise, lack of communication over a major natural resource can be a bad sign for cooperation when the resource in question is the Nile. More

More infographics from ‘A New Climate for Peace: Taking Action on Climate and Fragility Risks’ are available on NewClimateforPeace.org.

 

©

Century of Water Shortage Ahead? Lake Mead Drops Below Rationing Line For First Time in Its History.

Lake Mead Drops Below Rationing Line For First Time in Its History.

1075 feet. That’s the water level Lake Mead must stay above before mandatory multi-state water rationing goes into effect. A level just 25 feet above the highest intake pipe used to supply cities across the Desert Southwest. Last night water levels at the key national water storage facility fell below that hard line to 1074.99 feet — a record low never before seen in all of its history.

If water levels remain below the 1075 foot mark through January of 2016, then a multi-state rationing will go into effect (with most acute impacts for Arizona and Nevada). A rationing that will have serious consequences for desert cities across the Southwest, cities like Las Vegas which rely on Lake Mead for so much of their water.

Despite Lake Mead hitting the 1075 hard line, it appears that rationing may be forestalled through 2016. It’s a silver lining of all the severe summer storms that have rolled through the Colorado River Basin this spring and summer — pumping up water flows to Lake Mead and Lake Powell. A flush of much needed moisture that will, hopefully, prevent water rationing from going into effect during 2016. But prospects for the future, despite this temporary respite, are starting to look a bit grim.

Risk of Future Megadrought

The trend set in place by a human-forced warming of the Desert Southwest has resulted in an increasing number of dry years. The added heat forces water to evaporate more rapidly. So even when it does rain an average amount, moisture levels still fall. The result is not only an increase in single year droughts, but an increased risk of decadal droughts (called megadroughts).

As the years progress and more of the impacts of human-forced global warming become apparent, the drought impacts and severe drought risks are only expected to rise. For according to a recent Cornell University report (2014) the chance of a 10 year drought for the US Southwest under a moderate warming scenario (RCP 4.5) is 50% this century (greater for states like Texas, Oklahoma, New Mexico, Arizona, and Nevada — see graphic below). The chances of a 30 year drought range from 20-50 percent depending on the severity of the human greenhouse gas emission. More

 

©

Parched Caribbean faces widespread drought, water shortages

The worst drought in five years is creeping across the Caribbean, prompting officials around the region to brace for a bone dry summer.

From Puerto Rico to Cuba to the eastern Caribbean island of St. Lucia, crops are withering, reservoirs are drying up and cattle are dying while forecasters worry that the situation could only grow worse in the coming months.

Thanks to El Nino, a warming of the tropical Pacific that affects global weather, and a quieter-than-normal hurricane season that began in June, forecasters expect a shorter wet season. That means less rain to help refill Puerto Rico's thirsty Carraizo and La Plata reservoirs as well as the La Plata river in the central island community of Naranjito. A tropical disturbance that hit the U.S. territory on Monday did not fill up those reservoirs as officials had anticipated.

Puerto Rico is among the Caribbean islands worst-hit by the , with more than 1.5 million people affected by the drought so far, according to the U.S. National Drought Mitigation Center.

Tens of thousands of people receive water only every third day under strict rationing recently imposed by the island government. Puerto Rico last week also activated National Guard troops to help distribute water and approved a resolution to impose fines on people and businesses for improper water use.

The Caribbean's last severe drought was in 2010. The current one could grow worse if the hurricane season ending in November produces scant rainfall and the region enters the dry season with parched reservoirs, said Cedric Van Meerbeeck, a climatologist with the Caribbean Institute for Meteorology and Hydrology.

"We might have serious water shortages ... for irrigation of crops, firefighting, domestic consumption or consumption by the hotel sector," he said.

The Caribbean isn't the only area in the Western Hemisphere dealing with extreme water shortages. Brazil has been struggling with its own severe drought that has drained reservoirs serving the metropolis of Sao Paulo.

In the Caribbean, the farm sector has lost more than $1 million in crops as well as tens of thousands of dollars in livestock, said Norman Gibson, scientific officer at the Trinidad-based Caribbean Agricultural Research and Development Institute.

On St. Lucia, which has been especially hard hit, farmers say crops including coconuts, cashews and oranges are withering.

"The outlook is very, very bad," said Anthony Herman, who oversees a local farm cooperative. "The trees are dying, the plants are dying ... It's stripping the very life of rivers."

Officials in Cuba say 75 percent of the island is enduring a drought that has killed cattle and destroyed thousands of hectares (acres) of crops including plantains, citrus, rice and beans. Recent heavy rains in some areas have alleviated the problem some, but all 200 government-run reservoirs are far below capacity.

In the nearby Dominican Republic, water shortages have been reported in hundreds of communities, said Martin Melendez, a civil engineer and hydrology expert who has worked as a government consultant. "We were 30 days away from the entire water system collapsing," he said.

The tourism sector has also been affected.

Most large hotels in Puerto Rico have big water tanks and some recycle wastewater to irrigate green areas, but many have curtailed water use, said Frank Comito, CEO of the Florida-based Caribbean Hotel & Tourism Association.

Other hotels have cut back on sprinkler time by up to 50 percent, said Carlos Martinez of Puerto Rico's Association of Hotels. "Everybody here is worried," he said. "They are selling water tanks like hot cakes ... and begging God for rain."

Guests at Puerto Rico's El Canario by the Lagoon hotel get a note with their room keys asking them to keep their showers short amid the water shortage. "We need your cooperation to avoid waste," says the message distributed at the front desk of the hotel in the popular Condado district.

At the Casa del Vega guesthouse in St. Lucia, tourists sometimes find the in their rooms turned off for the day, preventing them from taking a shower. "Even though we have a drought guests are not sympathetic to that," hotel manager Merlyn Compton said. More

 

©