The National Park Service is worried about water. More specifically, it fears that the underground flows that feed the fishponds and anchialine pools at Kaloko-Honokohau National Historical Park will be interrupted or polluted if areas mauka of the park are built out to the extent allowed by current zoning and planning maps.
At a public hearing on the Hawai`i County update to its Water Use and Development Plan (WUDP), representatives of the park voiced concerns that the sustainable yield in the Keauhou aquifer system would be tapped out.
“While water resources along the Kona Coast are susceptible to pumping from higher elevation and coastal wells,” park Superintendent Kathy Billings said in prepared testimony, “cultural and ecological uses of groundwater are not recognized in the WUDP update, nor were they explicitly considered in the state’s determination of the sustainable yield.”
Billings went on to caution that continued permitting of municipal and private wells in the Keauhou aquifer could jeopardize “the exercise of traditional Native Hawaiian activities and culture and the diverse habitat of aquatic communities in the National Park.”
In 1999, Billings continued, a comprehensive analysis of the impacts of groundwater use on the water resources at the park found that “if all wells permitted prior to 1998 were pumped at their maximum rate, groundwater discharge at the coastline in the National Park would be reduced to 47 percent of the 1978 rate” – when the park was established – “and water levels in the National Park would decline about 0.6 feet.” Apart from the quantity of water available, Billings noted that the development of inland wells would also have an impact on the salinity of groundwater at the inland boundary of the park.
She then encouraged the chairperson of the state Commission on Water Resource Management (CWRM) to recommend that the commission designate the Keauhou aquifer system as a Water Management Area, an action that would give the commission tight control over all new uses of groundwater in the region. Stretching from Ka`upulehu in the north to Keauhou in the south, the aquifer system provides water to Kailua-Kona, the Four Seasons resort, the Keahole airport, luxury developments and hotels in Keauhou, major shopping centers, and too many subdivisions, both built and planned, to list. Sustainable yield for the Keauhou aquifer system is set at 38 million gallons a day (mgd).
According to the WUDP update, which has yet to be adopted by the commission, the sustainable yield for the entire Hualalai aquifer sector (consisting of the Keauhou and the Kiholo aquifer system, to the north) is 56 million gallons a day, with present usage about half that. Zoning that is already in place will drive total demand to 43 mgd, if fully exploited. The county’s Land Use Pattern Allocation Guide allows development that would use more than 200 mgd, or nearly four times the sustainable yield. Although the WUDP update states that “demands will not approach the sustainable yield for some time,” it advises the county to begin now to consider measures to control future water demands. “It would also be prudent,” the WUDP update adds, “for county planning officials to re-examine land use policies; controlling the development density should be considered.”
In mid-October, Lenore Ohye, a hydrologic planner on CWRM’s staff, said that her office was working on a response to Billings’ letter and hoped to have it out to her by the end of the month.
“We have had internal discussions on the subject of designation,” she told Environment Hawai`i. “The current position of the deputy and chair” – that would be William Tam, deputy director of the Department of Land and Natural Resources and CWRM administrator; and William Aila, CWRM chair and head of the DLNR – “is that designation is not warranted at this time. … One of the findings in the update is that in the next 20 years, if you look at demand and assume all demand is met throughout groundwater, it still didn’t come up to the 90 percent criterion for designation…. Maybe in a year or two, when more information is available, we’ll revisit the issue.”
Still, Ohye acknowledged that water use in the dry Kona area was an ongoing concern to the Water Commission. Although the entire data collection branch of the commission was “RIFFed” in 2009, she said, the remaining staff are still traveling to Kona regularly and trying to collect baseline data so that the impacts of cumulative pumpage can be evaluated. In Kona, “we have a monitoring network established since 1993, and we’ve been trying to collect data continuously” since then, she said.
Since the August hearing on the county WUDP update, “we’ve met with a National Park Service hydrologist, engineers from the county Department of Water Supply, the U.S. Geological Survey, and private hydrologists,” Ohye said. “We’re trying to come together and develop a more robust monitoring plan to address Park Service concerns. We’ve had a couple of meetings, and the last one was really fruitful.”
Complicating matters, Ohye said, is the fact that a recent U.S. Geological Survey study of groundwater recharge on Hawai`i island came up with some surprising results. “It showed that the recharge in the Keauhou aquifer is much more than was previously estimated,” she said, adding that if the new recharge figures were plugged into the county’s WUDP update, it would dramatically increase the sustainable yield for the Keauhou aquifer system – from 38 mgd to 67 mgd. “It’s not quite double, but it is considerably more,” she said.
The report Ohye was referring to is “A Water-Budget Model and Assessment of Groundwater Recharge for the Island of Hawai`i,” by John Engott, a hydrologist in the USGS Pacific Islands Water Science Center. Engott modeled rainfall and runoff across the island, looking at soil composition, vegetation, urban uses, and other factors, to come up with more refined estimates of recharge for each aquifer system. Of the island’s 24 aquifer systems, Engott found that the recharge rates assumed in 1990 were too low in all but six. Of the six where recharge had been overestimated, Engott found three where the difference was 29 percent or higher (all in Kohala). But recharge rates for the remaining 18, he concluded, had been underestimated by as much as 264 percent (in the case of Hilina aquifer, within the boundaries of the Hawai`i Volcanoes National Park).
For the Keauhou aquifer system in particular, Engott came up with an estimated recharge of 86 mgd, some 77 percent higher than the recharge rate used in the CWRM documents. According to Roy Hardy of the commission staff, the reason the recharge rates are so much higher than previous estimates has to do with the fact that fog drip has been included. “There are substantial regions of fog drip in Kona, especially at the higher elevations,” Hardy told Environment Hawai`i.
In his modeling, however, Engott relied heavily on average rainfall measures in a time series that ran from 1916 to 1983. Since then, Ohye said, “there’s been declining trends in stream flow and rainfall. Unfortunately, the recharge model didn’t incorporate new rainfall data” found in University of Hawai`i professor Thomas Giambelluca’s updated rainfall atlas, released just last month. “We’re hoping USGS can update the recharge model” using the newer data, Ohye said.
In her comments on the WUDP update, park superintendent Billings referred to the Engott study, but also noted that recent drought conditions might have an impact. “A 2003 analysis of water level data from North and South Kona initiated by the commission suggested that a slow decline of water levels in some of the higher elevation wells may be related to climatic conditions,” she wrote. “Long-term drought is of concern because a decline in precipitation levels contributes to l
ower groundwater recharge, lower aquifer storage, lower water levels, and less groundwater discharge to water resources in the National Park.”
Another recent study, supported by very deep wells drilled on either side of Hawai`i island, suggests that fresh water reserves may lie below saltwater
Hardy acknowledged that the Hawai`i County WUDP update, drafted in 2007, was already in need of revision. With many separate analyses ongoing at a given time, he said, there was the problem of “leapfrogging” – when one study is overtaken by another before the ink on the first one is barely dry.
Ohye said that after the August hearing on the county update, commission staff summarized the comments and forwarded them to the county Department of Water Supply. “Now we’re waiting for their response to the comments,” she said.
As for the long time lag between completion of the update and its eventual adoption, Ohye said that the commission staff was “trying to think of ways to make the plans more timely. It took the City and County of Honolulu six years to update two plans on O`ahu. We’re brainstorming ways to make these plans more of a living document, so we don’t have to wait so long between updates.” The last time the commission approved the Hawai`i County WUDP was in 1990.
Water Code Sets Forth Guidelines for WMA Designation
Whether and under what conditions the Commission on Water Resource Management can designate a water management area is set forth in the state Water Code, Chapter 174C of Hawai`i Revised Statutes.
Designation itself is to occur whenever “it can be reasonably determined … that the water resources in an area may be threatened by existing or proposed withdrawals or diversions of water.” The process can be initiated either by petition from affected users or on the recommendation of the chairperson of the commission (the Water Commission chair is also the director of the Department of Land and Natural Resources). “It shall be the duty of the chairperson to make recommendations when it is desirable or necessary to designate an area and there is factual data for a decision by the commission,” according to Section 174C-41.
In Section 174C-44, the Water Code sets forth eight scenarios that the commission should consider in weighing whether to designate. They are:
•1. Whether an increase in water use or “authorized planned use” may drive withdrawals to reach 90 percent of the sustainable yield of an aquifer;
•2. When the Department of Health has identified an “actual or threatened” degradation to water quality;
•3. Whether regulation is needed to preserve groundwater supplies for future needs, “as evidenced by excessively declining ground water levels;”
•4. Whether the current withdrawals are being done in such a manner that they endanger the stability of the aquifer by drawing saltwater into it;
•5. Whether chloride levels are increasing to the point they “materially reduce the value” of existing water uses;
•6. Whether “excessive preventable waste of ground water is occurring;”
•7. Whenever “serious disputes” over the use of groundwater exist;
•8. Whenever projects that have received any “federal, state, or county approval” may result in one of the preceding conditions.
Volume 22, Number 5 — November 2011