New & Noteworthy: Deep Percolation, Power Plan, and Corrections

posted in: April 2014 | 0
Deep Percolation: Will an aquifer recharge more quickly under a forest than a grassland? The answer, according to research carried out on leeward Haleakala, is an unambiguous yes.
Researchers with the U.S. Geological Survey simulated rainfall events at two areas at Auwahi, Maui. One was a grassland. The other was inside the area where Art Medeiros and his team have been working for the last 15 years to restore the dry forest that once covered the land.

Their conclusion: “restoration with native species at the Auwahi site has significantly altered the hydrology of the unsaturated zone to at least a 1-[meter] depth.” The movement of water through the soil was much more rapid that at grassland sites. “Reforested areas appear to facilitate deep water transfer relative to grassland sites,” they write. “More water may become available for [aquifer] recharge as it rapidly moves to the deep unsaturated zone below the root zone, where it becomes inaccessible to plants.” Possible reasons for this include the development of pathways in the soils that are created when tree roots penetrate into the ground.

Over and above the response to rainfall, there could be other natural processes that affect the amount of water percolating into the aquifer under forests, as opposed to grassland. The interception of cloud water is one such process; a previous study, the authors write, found that up to 46 percent of precipitation in the Auwahi forest results from orographic clouds coming down the slopes of Haleakala. “Thus,” they write, “it is possible that because it has more canopy surface area to intercept cloud water, the forest may receive more total precipitation than the grassland.”

The results of the research were published earlier this year in the journal Ecohydrology: “Assessing effects of native forest restoration on soil moisture dynamics and potential aquifer recharge, Auwahi, Maui,” by Kim Perkins, John Nimmo, Art Medeiros, Daphne Szutu, and Erica von Allmen.

Power Play: Start playing ball or your energy project is going nowhere. That’s basically what the Land Committee of the state Agribusiness Development Corporation seemed to say recently regarding a request by the Kaua`i Island Utility Cooperative for a right-of-entry through 2016 to investigate the use of ADC land in Kekaha for an energy storage project.

The utility wants to use reservoirs to store water that, if needed, could be run through a hydroelectric plant to create energy. But, according to Land Committee member David Rietow, KIUC has refused to negotiate a power purchase agreement with the ADC’s tenant group, the Kekaha Agriculture Association (KAA), on a separate energy project. The KAA has been working for years with Pacific Light & Power on a plan to generate enough renewable energy – through hydropower, biomass, etc. – to meet the tenants’ needs and to sell the excess to KIUC.

PLP has a license for lands in Kekaha, but its project has stalled. KIUC representatives have said repeatedly that the utility is not interested in buying electricity from the KAA or PLP.

At its meeting last month, the Land Committee recommended that the ADC board limit the right-of-entry term to one year and direct the KAA to coordinate with KIUC on access to the area. The KAA manages the ADC’s Kekaha lands.

If the KAA and KIUC manage in that time to establish a better working relationship, the right-of-entry could be extended, Rietow suggested.

Corrections: The short article on Papa`a Bay in our February issue incorrectly described a U.S. District Court decision in the case between Kaua`i County and Mandalay Properties. The court did not find that the county lost a road to the beach via adverse possession. Rather, the court found that the county failed to prove it ever owned the road, and that it lost its opportunity to claim a public access easement 20 years after a gate was erected in the 1950s.

And in our March issue’s article on water, we incorrectly identified Commission on Water Resource Management staffer Lenore Ohye as Lenore Nakama (as she was once known).

We sincerely regret these errors.


Volume 24, Number 10 — April 2014


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