Ewa Wetland

The Ewa wetland is an example of a landlocked wetland. With no obvious overland outlets to the ocean this wetland is still a catchment and detention basin and performs a vital function as drainage infrastructure. This neighborhood has no other stormwater drainage services, so this wetland takes all of the neighborhood’s rainwater. This area has natural uncompacted, porous, soils that are very efficient at infiltrating water into the water table/aquifer, and this site has a very low elevation averaging about 3.4 feet AMSL. This wetland becomes a lake after heavy rains and water flows into this wetland from many local sources, including Yee’s Wetland (orchard).

Ewa Wetlands looking east, with VFW in the foreground (Photo: Suzie Dorn)

Ewa Wetland is part of a much larger group of Wetlands that extend from the Piikea, Waipuilani, Yee’s, and VFW wetlands, with hydraulic connections to several others.

Groundwater Nexus: The Ewa wetlands is connected to many other wetlands through a series of underground connections, it also communicates directly to the ocean and the aquifer. Whatever happens to hydrology at this site affects the entire aquifer and ocean in this area of Kihei.

Natural Stormwater Retention Basin: The Ewa wetlands are the area’s de facto stormwater retention basin. As the lowest point in the surrounding neighborhood, this is where all of the rainwater and floodwaters accumulate. Fortunately this site has the capacity to hold millions of gallons of rainwaters. After storms, vast amounts of muddy stormwater sits within this “muliwai” and slowly feeds down to the aquifer over several days or weeks. This infiltration of stormwater through the ground filters out the sediments and many of the contaminants and protects the ocean from direct harm.

3D view model of Ewa Wetland site in Kihei

Wetland Services: The Ewa Wetland provides important services for the surrounding community as it mitigates and reduces the impacts from flooding. It also provides protection for the ocean waters and the nearshore ecosystems.

Flooding near Ewa Wetlands in Kihei

FLOODING: The Ewa Wetland in Kihei is one of the last open spaces on the makai side of Sh Kihei road, and is one of the lowest-lying places, at 3.4 feet above sea level. This is where floodwaters accumulate when it rains. Ewa is a 7.2 acre land-locked wetland that helps mitigate flooding to the surrounding neighborhood. Ewa is connected to at least 7 other wetland sites that share a common underground aquifer that is also connected to the ocean.

NEIGHBORHOOD: Ewa neighborhood residents have been battling flooding for decades and waiting for the county to improve drainage infrastructure.

NATURAL INFRASTRUCTURE: These last remaining wetlands in Kihei are nature’s drainage infrastructure. If we lose this wetland the neighborhood will be underwater when the next flooding rains come.