The Maui Board of Water Supply has signed a cooperative agreement with the U.S. Geological Survey to develop a numerical model that will help the county better understand groundwater movement and the effects of different water withdrawal scenarios in a large section of west Maui. The county had to sign the agreement by January 19 if it wanted to keep the state Commission on Water Resource Management from designating West Maui’s ‘Iao and Waihe’e aquifers as groundwater management areas.
At the Water Commission’s November 20 meeting, Earthjustice attorney Kapua Sproat and about dozen concerned citizens spent hours arguing that it should designate the ‘Iao and Waihe’e aquifers, critical to Maui’s domestic water supply, as groundwater management areas. Sproat’s client, the Maui Meadows Homeowners Association, had petitioned for this in July 2001 and now, nearly 18 months later, the commission was finally ready to vote on the matter. After meeting in closed session to discuss legal issues, the Water Commission accepted the findings of its staff that the aquifers were indeed threatened with overpumping, but stopped short of approving the staff’s recommendation that the aquifers be designated groundwater management areas.
When aquifers are in danger of being over-exploited, the state Water Code requires the commission to designate them as groundwater management areas. After that, permits from the Water Commission are required for well drilling and pumping. In evaluating each permit application, the commission would determine whether the withdrawal was for a reasonable, beneficial use. Permittees are also subject to a pumping limit at specified wells.
What prompted the Maui Meadows group to petition for designation was the trend of aquifer heads to drop and salinity levels to rise in the ‘Iao and adjoining Waihe’e aquifers. After months of hearings and research, the Water Commission staff found that conditions warranted designation.
Yet the commission voted against designation.
This, says Sproat, is illegal. If the commission accepts the staff’s findings of fact, she says, the Water Commission has no choice but to designate the aquifers as groundwater management areas.
At the meeting, former state Health Director Bruce Anderson made the motion to accept the findings while denying the Maui Meadows petition. Under his motion, approved by the commission, new triggers for designation were established that, if pulled, would result in automatic designation. Formerly, the only trigger for automatic designation was if the average daily pumpage from ‘Iao reached 90 percent of the maximum sustainable yield of 20 million gallons a day.
Sproat wrote, “Unfortunately, the triggers will do nothing to improve the condition of either aquifer. They will – at most – maintain the status quo of both aquifers which, as Commission staff determined, is threatened.”
The Agreement
Under the cooperative agreement, which was signed on December 5, the USGS will conduct a four and a half year study to get a better understanding of groundwater flow in and around the two aquifers. Stephen Gingerich of the USGS says the agency will put up weather stations to assess rainfall, evaporation rates, and fog drip, among other things. The USGS, he says, will also “look at additional monitoring of wells in central Maui looking at streams so see how much groundwater comes through streams.”
The data collected, together with a review of existing data, will be used to develop what’s called a numerical model, which Gingerich says is a “numerical illustration of the physics of how groundwater flows.” With the model, the USGS can create a three-dimensional picture of groundwater recharge. All you have to do, he says, is, “Push a button and it solves math equations over and over again. It’s the same sort of model used when they design airplanes or air flow models that simulate wings.”
The State of ‘Iao and Waihe’e
Forty-eight wells, tunnels, and observation holes have been drilled into the ‘Iao aquifer in West Maui. From those wells, an average of 16 million gallons a day (mgd) is pumped to feed the needs of Waihe’e, Wailuku, Kahului, Pa’ia, Kihei, Wailea, and Makena, a broad-ranging district known as the Central Maui Service Area. The current level of pumping is 4 mgd shy of the 20 million gallons a day that the Water Commission established in 1997 as the ‘Iao aquifer’s sustainable yield. (The sustainable yield is the maximum amount of water that can be pumped over time without damaging the quantity or quality of water available from a given aquifer.)
Right next to ‘Iao is the smaller Waihe’e system, which is currently yielding an average of 5 million gallons a day, 3 mgd shy of its sustainable yield of 8 mgd.
Waihe’e lacks deep monitoring wells to assess fluctuations in levels of water and salinity. Reports from monitoring wells in the ‘Iao aquifer, however, have shown that the transition zone – the area of brackish water separating sea water from the fresh water lens that floats on top of it – is rising. In addition, two municipal wells that pump water from the ‘Iao aquifer have shown increases in salinity that are approaching the EPA’s guideline of 250 mg/liter.
According to commission staff, these problems were not the result of “regional degradation of the aquifer” but instead were attributable to localized problems associated with the positioning of wells and “up-coning,” which occurs when saltier water is drawn up directly under a well. Still, when the ‘Iao and Waihe’e aquifer systems were considered together, the commission staff found that there was a definite threat to their ongoing viability.
The ‘Iao system supplies 77 percent of central Maui’s municipal water. The 1990 Maui County Water Use and Development Plan estimates that the Central Maui Service Area will need 31.1 mgd by 2010. The commission found that pending projects as of 2002 indicate a projected use of 29.2 mgd.
“Long-range future demands to be satisfied through the CMSA may be at least 29.2 mgd,” the commission staff wrote. “Therefore, authorized planned uses exceeded the sustainable yields (‘Iao 20 mgd and Waihe’e 8 mgd = 28 mgd) available to the CMSA.”
The state Water Code lists eight criteria that commissioners must consider in determining groundwater management area designation. The code also requires the commission to designate if any one of these criteria is met.
In the case of the Waihe’e and ‘Iao systems, the commission agreed with its staff’s findings that not just one criterion, but two were met. First, the authorized planned use will cause the maximum rate of withdrawal to reach 90 percent of the aquifers’ sustainable yield. Staff determined that the combined maximum rate of withdrawal would exceed the sustainable yield by 1.2 mgd. Second, staff found that existing withdrawals endanger “the stability or optimum development of groundwater body due to up-coning or encroachment of salt water.”
For and Against
As serious as the staff findings were, the Maui Meadows Homeowners Association and one of its experts, William Meyer, a former chief hydrologist for the U.S. Geological Survey in Hawai’i, described the analyses of the commission staff as too conservative. In testimony submitted in October 2002, Maui Meadows informed CWRM that the sustainable yield for Waihe’e might be less than 8 mgd. John Mink, a hydrologist that CWRM sometimes employs, has stated in past testimony that the present yield of localized well systems in the southern tip of the Waihe’e aquifer is only 4 mgd.
Estimates of a 20 mgd sustainable yield for the ‘Iao aquifer were also too high, Maui Meadows contended. “Discussion coming from recent USGS studies has placed the sustainable yield even as low as 13-14 mgd,” Maui Meadows wrote.
Gingerich, a USGS hydrologist, testified at the commission’s November meeting that a lot of uncertainty surrounded the 20 mgd sustainable yield. A sustainable yield of 16 or 17 mgd was a better value, he told the commission.
Also, Maui Meadows argued that a third criterion for designation found in the state Water Code applies to the ‘Iao and Waihe’e aquifers – namely, that such designation “is necessary to preserve the diminishing ground-water supply for future needs, as evidenced by excessively declining ground-water levels.”
Water levels in ‘Iao have been dropping since 1982, but seem to have stabilized in the last three years. The commission staff’s findings of fact state that the decline is not excessive because recent levels have been stable despite drought conditions, declining levels are not aquifer-wide, and it is possible that the unmonitored southern portion of the aquifer may be in fine shape.
Opposition
A few private landowners and the Maui Farm Bureau opposed designation, but far and away the chief opponent of designation has been the Maui Department of Water Supply.
“Even with designation, the State would not be any more able than it is now to implement solutions,” former Department of Water Supply head David Craddick said at one public hearing. The best CWRM could do was set pumpage amounts and levy fines if they’re not met, he continued. CWRM “does not have the authority nor the staff to physically control or manage anything, nor the funds even to manage at the level we do.” Craddick said that more and better communication and coordination between the county, his department, the commission, the University of Hawai’i, and the USGS would do more to protect water resources than designation.
Ellen Kraftsow, also with the DWS, told the Water Commission in November that while the build-out of all approved plans would exceed the capacity of ‘Iao, it won’t happen soon. Furthermore, plan approvals do not come with a guarantee for water, she said, and developers whose projects’ water demand is estimated to total 3.8 mgd have been told to build their own water systems.
When determining the amount of future planned use, CWRM staff took into account building permits and water meter reservations and approvals. None of these, Kraftsow said, ties future use to ‘Iao or Waihe’e aquifers. “Surface water will in part serve those systems,” she said.
Instead of designation she suggested guidance from experts for well field placement, requiring county well users to submit monitoring and pumping reports, developing a county process for approving wells and a policy to determine availability of water, and state enforcement of underreporting.
She concluded that designation would be a distraction for CWRM and county staff. When commissioner Anderson asked if she thought the county had the expertise to protect the resource, Kraftsow noted that the county was in the process of hiring a hydrologist and had proposed developing a numerical model to the Board of Water Supply.
Going With the Flow
After an executive session, then-Water Commission chair Gilbert Coloma-Agaran moved to accept staff’s findings of fact and designate the ‘Iao and Waihe’e aquifers as groundwater management areas. Commissioner Herbert Richards seconded the motion for discussion purposes. Commissioner Anderson then moved that the commission accept the findings of fact, but suggested that the motion recognize “recent developments regarding governance” and “give the county a chance to show they’re serious.” He proposed reducing the existing automatic designation trigger to 90 percent of 18 mgd (16.2 mgd), require the county to develop a numerical model for development of ‘Iao and Waihe’e, and have a contract to do so in place within 60 days of November 20. If the new trigger is reached or if the county fails to produce a numerical model, the aquifer systems would automatically be designated.
“Why do that rather than designate?” Agaran asked. Anderson responded that he had concerns about whether the state was in any better position to manage the aquifers than the county. The two aquifers make up a small area, he said, and other water sources may come to bear. “There is a question whether there is a sufficient problem to warrant such Draconian action.”
East Maui Well Plan Draws Renewed Litigation
The Coalition to Protect East Maui Water Resources, Hui Alanui O Makena, and Ha’iku resident Mark Sheehan filed a civil suit last month challenging the Maui Board of Water Supply’s acceptance last October of a supplemental environmental impact statement for plans to drill county water wells in East Maui. The suit stems from a dispute dating back to 1992, when the Maui Department of Water Supply unveiled its plan to develop 10 wells on Maliko Gulch on the island’s east side. The wells, when completed, were to have provided about 16 million gallons of water a day for agricultural and municipal uses in central and south Maui. In September 1993, the coalition, Hui Alanui, Mary Evanson and Marc Hodges challenged the project’s EIS, saying it failed to assess the impact pumping 16 mgd would have on east Maui streams.
— Teresa Dawson
Volume 13, Number 8 February 2003