Deputy Director of Engineering Samantha Haritos shared an update on the city’s drainage projects during Friendswood City Council’s Dec. 5 meeting.
Four of the five buildings that will be demolished to create the Frenchmen's Creek Greenspace have closed with the fifth closing in late December or January. Following demolition, hydromulching and the transfer of the green space title, the project will finish in mid- to late spring 2023, Haritos said. It will be the city’s first Hurricane Harvey Community Development Block Grant-funded project to close out.
Of the three Forest Bend Offline Detention ponds, ponds B and C are under construction. A total of 1,100 cubic yards of material have been excavated from those ponds. Sidewalks are in progress, and the electrical work is completed for solar lighting.
The city is waiting on an additional $320,000 in funding from the Texas General Land Office. The project is scheduled to finish in late summer 2023.
“This project is coming along,” Haritos said. “There's no delays. Things are on schedule.”
Friendswood is working on initial design concepts for the three detention basins along Cowart’s Creek. Two of the ponds will potentially be 10 acre feet with the third around 5 acre feet to avoid removing the disc golf course. The city is awaiting a geotechnical report before engineering design can begin.
“Now that they have an idea what the dimension of the ponds could be, they’ll have to go and work out whether that's hydraulically possible,” Haritos said.
An interlocal agreement among Friendswood, the Harris County Flood Control District, Galveston County and the Galveston County Consolidated Drainage District for the FM 1959 detention basin, the Whitcomb offline detention basin and Whitcomb terracing has been executed. The HCFCD is tabbed as the lead agency for the three projects, City Manager Morad Kabiri said, but Friendswood will still have a say in the projects and be responsible for maintenance and operations expenses following the completion.
An engineering study for the FM 1959 basin has been completed, and a project kickoff meeting will be held in December or January for the parties involved, Haritos said.
“We’re really excited to get that going,” Harrios said.
The FM 1959 detention basin is estimated at 1,000-1,800 acre feet with the exact size to be determined in a year. Preliminary modeling showed a 1,700-acre-foot detention pond in that location would remove 40 homes from the Atlas 14 100-year flood plain, which was equivalent to the 500-year flood during Harvey.
“We’ll know more about how many homes are going to be removed as we move further along,” Harrios said.
More details about the Whitcomb offline detention basin and terracing are unknown until the city learns if it has received an additional $10 million from the state.
Friendswood paid over $954,000 toward the FM 1959 detention basin in November. It will owe an additional $7.05 million following preliminary and design engineering, which could be one to two years down the road, Haritos said.
The total cost of all three projects is over $60 million with $32 million-38 million estimated for the FM 1959 drainage basin alone. However, the cost will be shared among the agencies involved. The HCFCD is putting in over $13 million; Galveston County is contributing $7.5 million; and the GCCDD is offering $3.75 million.
“We promised the voters when they approved this bond that we would leverage that money, and that’s what we’re doing very well,” Mayor Mike Foreman said.
To fund this project, the city estimates an increase to the debt service tax rate of $0.015 or the movement of $700,000 from the general fund. This assumes a number of factors that could change, including a bond issuance in February and a 4.75% interest rate. However, Kabiri said if property values continue to increase as they have the past few years, the tax rate increase may not be as high as $0.015.
“Regardless, it will impact our tax rate because additional funds have to go to pay the mortgage payments for the debt issued,” Kabiri said.
