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Honorable Pete Hoffrnann, Chair And Members of the County Council HAWAII COUNTY COUNCIL County of Hawaii Page 2 January 22, 2007 to pollute natural bodies of water aze contained in the "first flush"-the first runoff after a hard rain. The goal of the program is primarily to reduce the potential for water pollution from sediments and suspended solids in the stormwater runoff. It applies to areas after construction has been completed. While construction is still underway, the primary permit requirements that deal with runoff aze the National Pollution Dischazge Elimination System ("NPDES") permit, and county gading and grubbing permits. One potential penalty for failure to enact such management measures is that the local government could lose its Coastal Zone Management Act funding. The Hawaii County Planning Deparhnent receives about $300,000/yr. in such funding each year, which it uses in its various coastal zone programs, such as reviewing SMA major and minor permits, enforcement of SMA violations, and a number of studies and educational programs, such as public access to the shoreline. The Planning Department and Department of Public Works, in consultation with the EPA and the State Office of Planning, have proposed a set of amendments to bring the county into compliance with the CZAIiA. For the most part, these amendments continue practices that have been typical in the County for many years, but aze not formally required by law. These amendments require that stormwater runoff from developed areas be drained into drywells or other approved infiltration devices that will cause the water to soak into the ground, up to the anticipated one-hour, ten year storm event. DPW has typically made this a requirement in the past for new subdivisions and for other developments as a flood control measure, so that a new development that adds impervious surfaces has to dispose of the one-hour storm ten year event on-site, rather than allowing this water to flow onto neighboring properties. Although the original purpose of the drywell requirement was flood control, the drywell also works as an infiltration device under the CZARA because it will filter out sediments and suspended solids (by filtering the water through lava rock) before it reaches any natural bodies of water. The amount of rain in the anticipated one-hour, ten year storm event differs in various parts of the island, from 2"/hr. in Kailua-Kona, to 5"/hr. in Hilo. This is well in excess of the amount that the EPA expects to be treated under the CZARA requirements. The proposed amendments to Chap. 23, 25, and 27 implement the CZARA as follows: Chap. 23 is the Subdivision Code. The amendment to sec. 23-92 would require that the subdivider construct a storm drainage system that will contain runoff and divert it to