Plans to make improvements to Manoa Stream were put on pause Tuesday after residents in the area voiced their concerns.
The state Department of Land and Natural Resources held an informal briefing along Woodlawn Drive to discuss the changes with residents.
The project aims to get rid of sediment that’s been building up over the years, and increase the capacity of the stream to prevent flooding.
Work involves repairing the grouted riprap apron, a sloped rock formation designed to disperse water and reduce erosion, around the Woodlawn Drive bridge. Plans also include removing trees along the bank that pose a potential hazard, and dredging roughly 400 feet downstream.
But residents say they weren’t informed of the plans, and wonder if the project will do more harm than good.
“Is there anything, you have a study done that shows once you do this dredging, the sediment won’t reappear?” asked former governor and Manoa resident Neil Abercrombie.
“We can’t guarantee it,” said Carty Chang, DLNR chief engineer.
“Why would you go ahead with this plan if you don’t even have an assessment, a study that shows if you remove the trees and if the soil is exposed on the basis of getting rid of sediment and doing the dredging, that you won’t have the sediment reappear right away?” Abercrombie asked.
There were also concerns over the impact of dredged sediment being stored close to university faculty housing for the duration of the project.
“The contractor is going to attempt to divert the water so he can be working in a dry area,” Chang explained. “He’s going to try to implement some type of bypass system where he’s going to put a pipe in the water and try to divert it around his work area, dry as much of the sediment out as possible, because it won’t be in the running stream. He’ll excavate it out and he will place it in those basins. If he’s able to place it in his truck, he will try to do that to minimize placement time on the site, but that’s something that has yet to be determined.”
“I just need to hear how you’re going to keep that safe, because my kids play right in front of there, and if it’s a three-foot pool, I’m really deeply concerned about safety for all of our kids,” said a resident.
“The area is not going to be open. We’re going to fence it. We just didn’t get around to fencing it. There’s going to be a dust screen along the fence so you can’t see inside it,” Chang replied. “As far as containment, it’s going to be like any construction site, you’re not going to have access into that site.”
“If there has to be sites of sedimentation drying at all, why not put them away from humans where CTAHR (University of Hawaii College of Tropical Agriculture and Human Resources) actually agreed to put them, or even in the parking lot at Manoa Innovation?” asked Kieko Matteson, University of Hawaii at Manoa associate professor.
On Tuesday afternoon, a department spokeswoman said “the decision was made to temporarily pause any construction work and re-evaluate some of the concerns that were brought up today, and also conduct additional outreach.”
DLNR says a previous meeting about the project was held on May 7 at Noelani Elementary School.
The project is expected to take nine months to complete. It is being done in collaboration with UH and the City and County of Honolulu.