A restoration is under way of nearly 40 acres of wildlife habitat within the 830-acre Kawainui Marsh, the largest remaining wetland in Hawaii.

Honolulu-bound motorists on Kalanianaole Highway between Castle Medical Center and Kapaa Quarry Road may have noticed beyond the brush that acres of the once-thick overgrowth of tall grasses and trees have been undergoing a dramatic transformation.

The U.S. Army Corps of Engineers and the Department of Land and Natural Resources broke ground June 28 for the construction of the Kawainui Marsh Environmental Restoration Project, which is nearing completion, possibly by the end of January or early February.

After six months nearly 40 acres of the overgrown, degraded marsh has been excavated and graded, and alien weeds have been removed to create landscaping for 11 ponds, earthen berms and a drainage channel.

The ponds cover less than 30 acres, and each is about 1 to 2.5 acres. Once filled with water, they will create a native habitat for four endangered Hawaiian waterfowl: the aeo (Hawaiian stilt), alae ula (Hawaiian moorhen), alae keokeo (Hawaiian coot) and koloa maoli (Hawaiian duck).

The shallow ponds, now just bare dirt, are separated by grassed earthen berms, which will provide access for maintenance vehicles.

The project calls for drilling several wells and seeding the berms with grass, now about half done, the corps said.

Olomana resident Sue Brown said she’s seen the clearing, large machinery and the drilling as she drives by.

"I’m definitely glad it’s not a development," Brown said. "I’m really glad they’re expanding the marsh. I hope they have a walkway so people can view it up close."

DLNR Director William Aila said at the start of the project that the restoration of the habitat "is expected to increase populations of endangered waterfowl, create more scenic open space and reduce upland runoff to coastal reefs and remove invasive weeds from the marsh."

The project, designed by Oceanit and built by Performance Systems Inc., is projected to cost $6.4 million and is 75 percent federally funded. The DLNR’s share is projected to be $1.3 million, or 25 percent of the total. Final costs will be available when the work is done.

The new ponds will eventually be filled with groundwater by 11 wells at varied depths, according to the Army Corps.

Two solar-powered well pumps will be used to supply the water.

"Water will drain out on the Castle Hospital side of the pond into a drainage channel that will convey water to the next pond," the Army Corps said in a written response to questions from the Star-Advertiser. "As an example, think of a taro loi style, where ponds are gravity fed. No water from the wells will empty into the marsh. Water will either go into the ground or evaporate."

DLNR’s Division of Forestry and Wildlife will adjust the depth of water as needed to attract the water birds, the Army Corps said.

The corps, responsible for the design and construction, will turn the project over to the state to operate, maintain and repair. DLNR has worked with the Kailua community and the corps for more than 15 years to develop a habitat restoration project, DLNR said.

The project administers portions of the 1994 Kawainui Marsh Master and Hawaii Endangered Waterbird Recovery plans, the department said.