Pa'auilo Final Enviromental Assessment

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PA`AUILO LANDS FINAL ENVIRONMENTAL ASSESSMENT 3.0 ASSESSMENT OF THE EXISTING NATURAL ENVIRONMENT, POTENTAL IMPACTS, AND MITIGATION MEASURES This chapter describes the existing natural environment of the Pa`auilo Lands and potential impacts that may result from the proposed sale of the lands. The chapter also describes mitigation measures to address potential impacts. 3.1 CLIMATE Because the project site lies between the 1,400 and 2,400-foot elevations on the northeast side of Hawaii Island,it is affected by the prevailing northeast trade winds,making the climate there cool and wet.Winds are generally northeast,with typical trade wind speeds of 10-15 miles per hour. Average annual rainfall in the general vicinity of the project site is approximately 70 inches. The average temperature ranges from approximately 57 degrees Fahrenheit to 70 degrees Fahrenheit (Pecs. Comm., Kelvin Sewake, University of Hawaii, College of Tropical Agriculture and Human Resources, July 28, 2006). Potential Impacts and Mitigation Measures The proposed sale and subsequent use of the Pa`auilo lands will not affect the regional climate. 3.2 TOPOGRAPHY AND GEOLOGY The Pa`auilo lands are located approximately 3.5 miles mauka of Hawaii Belt Road, on the middle slopes of Mauna Kea. The site slopes downward, generally from southwest to northeast, at an average rate of 11 percent. Ground surface elevations range from approximately 1,400 feet above mean sea level (amsl) to 2,400 feet above amsl. The Pa`auilo Lands are former sugarcane land, but are fallow now, and vegetated primarily in Guinea grass (Panicum maximum) and other introduced weedy grasses,herbs, shrubs, and trees. Soils within the project area derive from Mauna Kea Ash deposited between 65,000 and 250,000 years ago. In places, the Mauna Kea Ash is overlain by deposits laid down between 4,000 and 7,000 years ago (Wolfe and Morris 1996). Potential Impacts and Mitigation Measures No significant impacts to the regional geology and topography are anticipated as a result of the proposed sale or any subsequent use of the Pa`auilo Lands. 3.3 DRAINAGE The Pa`auilo Lands are designated Zone X by the Flood Insurance Rate Map, indicating that the lands lie outside the 500-year floodplain (Figure 8). The site contains four named gulches (Opihilala, Waipunalau, Pa`auilo, and `A`amanu), and slopes downward from southwest to 15