A $21 million project to improve the shoulders of Kawili Street in Hilo also will drill more than two dozen drywells along the length of the road.
The Hawaii County Department of Public Works is in the early stages of a construction project to improve East and West Kawili streets and Manono Street by installing a continuous sidewalk along the road, as well as other various pavement and striping maintenance.
As part of that project, the DPW announced on Dec. 30 an application to the state Department of Health requesting the county be allowed to construct 29 drywells along the project site to manage rainfall runoff.
DPW spokeswoman Sherise Kanae-Kane described the wells — specifically called drainage injection wells — as “basically an empty hole which accepts rainfall runoff through an intake structure at the ground surface level, contains the water, and allows it to percolate into the ground below.”
The wells would have a maximum diameter of about 6 feet and a maximum depth of about 25 feet, and collectively they would be able to drain up to approximately 27,410 gallons of fluid per minute.
DOH spokeswoman Kristen Wong said via email that the drywells are a routine project that the department does not expect will cause any problems. However, because the project is located mauka of a boundary called the underground injection control line — which delineates boundaries between underground sources of drinking water and other aquifers — Wong said that it nonetheless requires permit approval and a public comment period.
The improvements to Kawili Street, including the shoulders and wells, are estimated to cost about $21 million, which has not yet been secured, Kanae-Kane said via email. No specific timeframe for the project has been determined, but it is expected to take more than a year to complete, and the road is expected to still be usable during that time.
The public comment period for the drywells extends until Jan. 27. People wishing to comment on the matter should contact the DOH’s Safe Drinking Water Branch at (808) 586-4258.