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Archives for July 2016

Researchers reveal cost-effective path to drought resiliency

July 26, 2016

July 2016

(Kobayashi Comment:  This intriguing Stanford study may offer an answer to Hawaii’s future freshwater shortages…  Imagine routing Hawaii’s torrents of stormwater into the ground aquifers instead of washing brown water pollution onto our beaches and recreation areas…)

Strained by drought in recent years, California desperately needs more resilient water supplies. An affordable solution that provides a wide range of benefits is within reach, according to a new Stanford study.

 Published in San Francisco Estuary & Watershed, the study reveals the costs and benefits of using groundwater recharge and storage across the state. This process, known as “managed aquifer recharge,” or MAR, can incorporate co-benefits such as flood control, improved water quality and wetland habitat protection. The study found the median cost of MAR projects is $410 per acre-foot (the amount of water required to cover an acre of level land at a depth of 1 foot) per year. By comparison, the median cost of surface water projects is five times more expensive — $2,100 per acre-foot.

“We find that MAR is an effective and affordable way to balance local groundwater decisions with regional and statewide management,” said study co-author Debra Perrone, a postdoctoral scholar with Stanford’s Water in the West program.

Many local communities rely on statewide infrastructure to supplement their water supply. This water is costly and limited in supply, raising a need for cost-effective local storage options.

Managed aquifer recharge allows for local water storage, access and management to a much greater extent than large surface water reservoirs, which are often managed by state and federal entities. Although excess surface water can be limited in some regions of California, treated wastewater and urban stormwater offer sources for MAR that aren’t fully utilized by centralized surface water storage infrastructure.

MAR is particularly well suited to more populous and developed areas that can take advantage of large quantities of treated wastewater and stormwater runoff collected by extensive infrastructure for use in recharge. In more rural areas, MAR using excess surface water can still play an important role in replenishing groundwater basins and guarding against dry times.

“Every year, California lets 1 million acre-feet of treated wastewater flow to the ocean,” said co-author Melissa Rohde, previously a researcher with Water in the West. “Our research shows it would cost the state about $870 million to build the necessary MAR facilities to recover and store this water. That’s not a lot of money compared to the cost and energy required to transport water from large surface water projects or to desalinate ocean water.”

A water enigma

Groundwater supplies up to 60 percent of California’s water supply during dry years. Despite its crucial role in slaking the Golden State’s thirst, groundwater went largely unregulated until the 2014 passage of the Sustainable Groundwater Management Act. Therefore, statewide data on groundwater management generally and managed aquifer recharge projects specifically has been sparse or proprietary, generally not shared publicly.

This lack of information was highlighted with the 2015 passage of California’s largest-ever water-related proposition — the $7.5 billion Proposition 1. The bond promises almost $3 billion for water storage projects. Without data on relative costs and benefits, state and local water managers are hard pressed to make informed decisions on MAR projects.

In addition to new funding opportunities, the 2014 law puts the burden on local agencies for sustainably managing groundwater. So, local communities have more reason than ever to bank water sustainably. Managed aquifer recharge allows agencies to do that in ways tailored to a community’s resources.

Perrone and Rohde set out to identify costs and benefits of MAR projects around the state by mining applications for general obligation bonds from ballot propositions. In these publicly available forms, the researchers identified proposed economic costs and anticipated MAR project benefits. Then, they surveyed the projects’ managers to compare initial estimates with actual costs, and to identify advantages and limitations.

Looking to the future

As a changing climate, growing population and other factors put increasing pressures on water supplies, California’s need for long-term resilience will only intensify, the study noted. Conservation will only go so far. Flexible water storage options that can address changing conditions are essential. Therefore, it is likely that more water agencies will adopt MAR as a local management tool.


Story Source:

The above post is reprinted from materials provided by Stanford University. The original item was written by Rob Jordan. Note: Materials may be edited for content and length.


Journal Reference:

  1. Perrone, Debra; & Merri Rohde, Melissa. Benefits and Economic Costs of Managed Aquifer Recharge in California. San Francisco Estuary and Watershed Science, July 2016

Filed Under: Groundwater, Rainfall, Stormwater, Water Conservation, Water Contamination

Swimming safety: Newspaper analysis shows bacteria levels up, but (Big Island) beaches still within limits

July 3, 2016

July 2016
  • (Kobayashi Comments: I have elected include this in a freshwater news site because it touches on some issues which are also key to the freshwater issue.  According to the 2014 State of Hawaii Water Quality Monitoring and Assessment Report, the Big Island’s freshwater conditions are better than most of the other islands.  However fully a third of the streams on the island are listed as “impaired” which means one or more of their pollution measurements do not meet EPA standards and are being watched.
  • The good news is about 40% meet EPA standards for cleanliness while the remaining 30% are unobserved.  Similar to the problems cited in the beach article, sampling programs have been cut and collection is limited.  So now here is the beach article…)
By Nancy Cook Lauer West Hawaii Today ncook-lauer@westhawaiitoday.com

KAILUA-KONA — Michael Kahookaulana connects a long green garden hose to a faucet behind the lifeguard stand at Laaloa Bay Magic Sands beach and rinses himself off before turning the hose on his dripping baby and bikini-clad wife.

A local and longtime surfer, Kahookaulana knows the importance of promptly removing the saltwater, sunblock residue and whatever else is lurking in the turquoise waters at one of the Big Island’s most popular beaches.

He also has a good idea — even without looking at the data provided by the state — which of the island’s beaches are cleanest, and when is the best time to avoid them.

“Here, there’s a lot of oil from suntan lotion,” he said Thursday. “On the Hamakua coast, you get river water mixed in and whatever it’s bringing down from the fields. … The quality of the water, you can really tell. I definitely know the water all around the island.”

So does Neil Mukai. The only state environmental health specialist on the island charged with water sampling, Mukai spends his workday driving his state truck beach-to-beach, surf-spot-to-surf-spot, dipping up water in his battered metal bucket.

Despite some short-term spikes in fecal bacteria, waters around the Big Island show levels well below those considered unsafe. But most of the average readings for enterococci — the primary measure of contamination used by the U.S. Environmental Management Agency — have been steadily increasing over the past 10 years.

In fact, average beach fecal bacteria levels have increased five-fold between 2006 and 2016 at key West Hawaii beaches and 134 percent on the Hilo side.

See the rest of the article here…

Filed Under: Water Contamination

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