Pa'auilo Final Enviromental Assessment

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PA`AUILO LANDS FINAL ENVIRONMENTAL ASSESSMENT 3.5 GROUNDWATER RESOURCES AND HYDROLOGY Pa`auilo sits atop the Pa`auilo Aquifer, which is a component of the East Mauna Kea Aquifer System. The Pa`auilo Aquifer has a sustainable yield of approximately 60 million gallons per day (CWRM 1995). According to the County of Hawai`i Department of Water Supply, the closest available Department of Water Supply facility is a 6-inch waterline within Pohakea Mauka Road, approximately 4,000 feet from the northwest corner of TMK 4-3-11:02. The Department is not allowing any additional services from the existing 4-inch waterline within Pohakealani Road near the southeast corner of TMK 4-3-11:02 until extensive water system improvements are made. Potential Impacts and Mitigation Measures The proposed sale of the Pa`auilo Lands will not directly introduce new residents to the project area. Additionally, no direct utility upgrades are being provided to the parcels. Therefore, should the"worst case" calculation of 32 farm dwellings be constructed,it would be expected that water use would be limited until extensive water system improvements are made. Water supply for future dwellings will possibly be limited to rain-water catch stored in tanks or reservoirs. 3.6 NATURAL HAZARDS Natural hazards that could impact the property include earthquakes, volcanic eruptions, hurricanes, and flooding. The island of Hawaii is associated with volcanic eruption and earthquakes. The U.S. Geological Survey (USGS) has developed lava-flow hazard zones with a numerical rating of 1 to 9, with 1 having the greatest risk. The Pa`auilo Lands are in Lava-Flow Hazard Zone 8, which indicates that only a few percent of this area has been covered by lava in the past 10,000 years (USGS, 1992). Mauna Kea last erupted approximately 4,000 years ago. The State of Hawaii has been affected twice in the past two decades by devastating hurricanes— Hurricane `Twa, in 1982, and Hurricane `Iniki in 1992. The most recent series of earthquakes, with magnitudes of 6.7 and 6.0, occurred at Kiholo Bay on October 15, 2006. While it is difficult to predict these natural occurrences, it is reasonable to assume that future events could occur. The project area, as the rest of the island and state, is vulnerable to the destructive winds and torrential rains associated with hurricanes. Honoka`a High School, located approximately 6.8 miles west of the project site,is a designated Emergency Evacuation Center for the Pa`auilo area (Personal Communication, Hawaii County Civil Defense). According to the Flood insurance Rate Map (FIRM), the project site is designated as Zone X meaning that it is located outside of the 500-year floodplain (Figure 8). The site is located approximately 2.3 miles from the shoreline and is outside of the tsunami evacuation area. Potential Impacts and Mitigation Measures The sale of the Pa`auilo Lands is not expected to exacerbate any hazardous conditions. 23