Honu'apo Park Resource Management Plan

2.2.1 Climate
Honuÿapo Park Final Resources Management Plan
The climate of the project area is semi-arid and mild. Average daily temperatures
range from the low 70s (F) to the mid 80s, depending on the time of day and
season, and mean annual rainfall is about 45 inches. Monthly average temperatures
vary only about five degrees from the warmest months of August and September to
the coolest months of December and January. Wind speeds average 10 to 15 miles
per hour with gusts frequently exceeding 20 miles per hour. Prevailing wind
directions are northeasterly and easterly. High winds and relatively clear skies lead
to high rates of evapotranspiration.
Air pollution in Ka‘ü is mainly derived from volcanic emissions of sulfur dioxide
(SO2), which convert into particulate sulfate and produce a volcanic haze (vog) that
periodically blankets the district. Changing levels of SO2 output from Kïlauea
volcano, as well as variable winds and weather patterns, can drastically affect the
level of vog pollution in Kaÿü. The State Department of Health and U.S. Geological
Survey (USGS) continuously monitor SO2 levels throughout the island of Hawaiÿi.
Vog has become more prevalent in Kaÿü since the opening of a new vent at
Halemaumau Crater at the summit of Kilauea Volcano in March 2008. Recent SO2
emission rate measurements were about 660 tonnes/day in April 2010, well above
the 2003-2007 average of 140 tonnes/day. Due to the unpredictable nature of
volcanic eruptions, it is difficult to forecast how SO2 emissions from Kïlauea
Volcano will fluctuate in the future.
2.2.2 Topography
The topography at Honuÿapo is relatively level throughout the area of the park,
with lowest land elevations near Honuÿapo Estuary and Honuÿapo Bay, near sea
level, and slightly higher elevations in the central and northern sections of the park
at 20 to 40 feet above mean sea level.
Honuÿapo Park represents a low point in the coastal topography, with the tall, steep
Pohina cliffs located just to the south of the park, and a massive ÿaÿä flow along the
northern boundary of the park. About 1,000 feet inland from Honuÿapo Park, the
lowland plain begins to ascend into moderate to steep slopes up the flank of
Mauna Loa.
2.2.3 Regional Geology and Hydrogeology
Extending north from Ka Lae Point the southeast coast of the island of Hawaiÿi is
made up of rocky headlands that transition to a low-lying coastal plain in the
vicinity of Honuÿapo Bay. Surface lava flows in the coastal zone surrounding
Honuÿapo come from Mauna Loa volcano and range in age from 200 to 5,000
years before the present.
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