County of Hawaii - Flood Awareness

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Drainage Systems

Ki‘ilae stream in Hōnaunau clogged with vegetationDrainage systems are watercourses such as rivers, streams, channels and other topographic features over which waters flow periodically. Drainage and flood problems may be caused when debris or overgrown streambed vegetation accumulates and clogs waterways, or when the capabilities of existing drainage systems are exceeded during heavy rains. Ki‘ilae Stream (above) in Hōnaunau, South Kona, is shown clogged with vegetation.

When water damages property, disputes rise among neighbors which could lead to mediation or court .  The article, “Neighbor Disputes Over Water,” produced by Nolo discusses the murky legal issues around these disputes.

In 1970, the County of Hawai‘i Department of Public Works adopted the Storm Drainage Standards for the design and development of storm drainage facilities. The department administers the County’s drainage system management according to Chapter 27 of the Hawai‘i County Code (see Chapter 27, "Enforcement," Sections 27-32 through 27-38) and the Hawai‘i Revised Statutes 46-11.5. This includes the enforcement of drainage system maintenance to assure that drainageways, floodways, stream beds and banks, channels—whether natural or artificial—and watercourses are free of debris and obstructions.

The Department also administers and enforces standards for construction and improvements adjacent to drainage facilities. It provides flood control and erosion mitigation on all developed properties through its grubbing and grading ordinances as directed in Chapter 10 of the Hawai‘i County Code. For agricultural operations, landowners and lessees are encouraged to work with the United States Department of Agriculture's Natural Resources Conservation Service  in developing and implementing soil and water conservation plans.

Keep waterways flowing!

It is illegal to dump debris into waterways. It is also an owner’s responsibility to keep waterways on their property free of debris, vegetation or obstructions.

Report debris or obstructions in drainage systems to the Department of Public Works Highways Maintenance Division, 808-961-8349.