Unregulated Development

Unregulated development: Overdevelopment in the Kihei area was unregulated during the building booms of the 70’s and 80’s, but it is only fairly recently that the true extent of the flooding hazards has been calculated. The area is subject to FEMA regulations and flood insurance requirements. New developments are subject to tougher regulations and requirements. The question isn’t if you can build a high-density projects in a floodzone-wetland, the real question is if you should do it?

Development increases stormwater production: Extensive housing and urban development in the area has incrementally increased surface runoff. And every new paved parking area and new roof increases rainwater sheeting and adds to the total volume of stormwater that needs to be managed. But stormwater, particularly in lower parts of Kihei, is currently not being managed, and inadequacies in Kihei’s stormwater infrastructure are glaringly evident every time it rains.

Drainage canals covered over: Housing developments and condos often cover over natural water drainage canals. Storm-water infrastructure used to be moved underground and covered over on former housing developments. This style of underground storm water diversion is difficult to maintain and can become neglected and blocked. There are several large developments projects on the mauka (uphill/mountain) side of Kihei that have underground stormwater diversions that are not readily accessible. These types of projects have contributed to a haphazard and disconnected system of ad-hoc drainage measures, that are not part of any coordinated or centrally-managed drainage system that might properly handle stormwater runoff. 

Developments diverting their stormwater:  On the uphill side of Kihei large developments created underground stormwater canals that were not connected to proper drainage ditches. They simply channeled the water away from their properties and onto vacant land, without adequate regard for the neighboring homes downhill from them that are negatively affected.

100-year floods: Scientists estimate a 100-year storm would funnel a volume of water into parts of Kihei equivalent to about two-thirds the summertime flow of the Colorado River — 14,000 cubic feet per second, enough to sweep away some homes.

Former public works director David Goode said this about flooding in Kihei:  “The least costly thing might be to move people out. Has that ever been seriously considered? Well, there are instances of complete towns along the Missouri River that were removed,” said Goode. “That’s not gonna happen in Kihei, but there might be a few where it doesn’t make sense to have a structure right in the middle.” “It really could be a lot worse. People need to plan for that, understand that, deal with it on their own level accordingly. And we’ll try to deal with it on the regional level,” said Goode. Read the full article here: https://www.hawaiinewsnow.com/story/14702361/special-report-kihei-underwater/