A $23.5 million detention basin in Henderson was completed in early October, and about 186 acres downstream from it will no longer be considered a flood zone.
No residential homes, though, are in the existing Zone A — a federal designation meaning an area is at a high risk to flood.
Pittman North Detention Basin — the 100th basin the Clark County Regional Flood Control District has constructed — is off St. Rose Parkway near the Lion Habitat Ranch, M Resort and the Raiders under-construction headquarters and practice facility.
Work on the detention basin began in July 2018, and the city oversaw construction. The project was substantially complete the first week of October, but some maintenance work — such as excavation and hauling — is still underway.
“The Pittman North Detention Basin was pursued to protect that area from flash flood run-off,” said Erin Neff, spokeswoman for the regional flood control district, in an Oct. 16 email to the Las Vegas Review-Journal.
It will also capture runoff from McCullough Hills to the south and a little from the Spring Mountains to the west, she said.
The detention basin — constructed by Fisher Sand & Gravel — can hold 1,533 acre-feet of water, the equivalent of 500 million gallons. It connects with some of the flood control district’s underground facilities.
The new basin benefits the “whole downstream area” and will help maintain the flow rate at other flood control facilities, said Ed McGuire, public works director for the city.
While the new detention basin was a project in Henderson, “it’s really regional in nature,” he said.
The basin will also help prevent water from inundating roads such as St. Rose Parkway, McGuire said. And for the nearby St. Rose Parkway Trail — which has been washed out a few times over the last decade — “things like that should be eliminated.”
There’s a flood zone downstream of the new basin, but a process is underway to petition the Federal Emergency Management Agency to remove the designation now that construction of the basin is finished, Neff said.
FEMA requires those who live in a high-risk flood area — and have a mortgage from a federally regulated or insured lender — to buy flood insurance, which can be costly.
The area surrounding the new Pittman North Detention Basin is mostly commercial and industrial, along with some land officials say would be difficult to develop.
The basin is behind Lion Habitat Ranch, a nonprofit wildlife sanctuary. President Keith Evans wrote in an Oct. 22 email to the Review-Journal, “I was never in the flood zone but the basin has caused lots of damage to our business while it was being built.”
He said there wasn’t any physical damage to his property, but he wasn’t able to use an access road for more than a year, which affected visitors to the ranch.
The regional flood control district — which was created in 1985 — plans to build another 36 detention basins and 201 miles of channels in the coming years.