Council to consider ditching current City drainage plan



Prior to July, there was no sign Liberty Hill had issue with its extensive drainage master plan, though very little action had been taken to implement the plan since it was adopted midway through 2018.

But in early July Mayor Rick Hall announced to the Council that he was in discussions with Halff Associates to revisit the City’s drainage improvement needs, and believed he would be able to come back with a more affordable plan to address the issue.

The plan approved in 2018 was developed by K. Friese and Associates and was presented in phases.

The issue was raised at both July meetings, with Hall sharing a one-page synopsis of the refined plan with the Council. The Phase 2 report was 72 pages with methodology, funding recommendations, maps, and a detailed list of 17 identified problem areas. The City invested $22,471 into the study.

“The company that came back and did that drainage study for us, their proposal was somewhere in the neighborhood of about $7 million,” Hall said. “If that’s what we need to spend that’s what we need to spend, but the proposal was buying a lot of property around town and turning that into retention ponds to slow the water down. I’ve spoken with our current engineers and other engineers and (Halff Associates) actually looked at our current drainage plan and their comment was that ‘we wish every city we’ve done a drainage mitigation plan for was set up as Liberty Hill being that the center of the town is at the highest point with a river to the north and a river to the south.’”

In the Council packet on July 27, the Council was given the new proposal which emphasized five steps, including flood risk refinement, conceptual drainage capital improvement project refinement, drainage maintenance, a drainage utility rate study and drainage criteria recommendations. The estimated budget for the five areas to be addressed is $265,000.

“Their proposal to get the flooding down and maintain it is to open up our natural canals that we have here, and our channels in the city, and to get that water to the river instead of holding it back and creating more problems down the road for us,” Hall said. “This estimate came back at about $265,000 for their proposed plan for us.”

The Council didn’t vote because the item was not on the agenda as an action item, but Hall encouraged the Council to approve moving forward with the new plan.

“I would like to entertain taking this estimate and moving forward with them to help them to start working on getting contracted crews out here to start working on it,” Hall said. “This is a much better cost to the city as far as mitigating our drainage and our flooding potential. Will this handle 100 percent of it? No, but it will handle about 95 percent of it.”

Hall said the intent was to have the item on the Aug. 10 agenda for a vote.

The sudden change in direction on how to best address drainage issues left some who had worked on the previous plan scratching their heads.

“Council just has to make the hard decisions like how are we going to move forward with this plan and how are we going to pay for it,” said former Liberty Hill Director of Planning Sally McFeron. “To start all over again, with a new drainage plan will set the city back another three or four years in trying to come up with something that’s comprehensive.”

She added that like the transportation plan, creating and adopting a drainage plan takes many steps.

“Those plans were adopted through a process,” she said. “There was a public process, there was Parks Board and Planning and Zoning involvement, we hired professional outside engineers. This was done with data and with research. They are valid plans. And for the Mayor to come through and say ‘we’re going to get rid of this plan’, there was no public input with that. There was no process.”

Former City Administrator Greg Boatright echoed those thoughts, but admitted the Council let the plan sit.

“There was a lot of time and effort and a lot of interaction with the Council and they can put their own spin on it, but the truth is there was a good study that was done, there was a good plan in place to make it happen, but there was a lack of commitment from the Council to follow through.”

The desire to change the plan was not a big surprise to Boatright.

“I think the plan Friese came up with was a good plan, and it was phased to where we could take it in small bites,” said Boatright. “It’s the same old story. Anything the old regime did, the old council or staff did, is all wrong and so we need to go back and fix it and put our stamp on it. That’s where we’re at and that’s a continual pattern we see.”

The original plan
Detention and retention were key factors in the original plan.

K. Friese and Associates identified the different drainage basins in the city, which also helps predict where strategic detention locations can be placed to make the most impact on drainage issues.

The first presentation was on the city’s drainage basins, demonstrating where stormwater tends to naturally go as it runs into tributaries.

“It is a really unique geography, from a drainage perspective, that the city has,” said Chad Cormack an engineer with K. Friese & Associates at the time the plan was presented. “You don’t have any other cities that drain to you, which is a common problem, so we really have full control over our drainage basins and how we are going to regulate stormwater.”

By identifying the different basins, the city can zero in on the particular issues with each.

“It will aid future regulation,” Cormack said. “Each one of these basins has different characteristics. Some of the basins have a lot of problem areas already, some of them lend themselves well to regional detention, and some of them are undeveloped.”

Once the drainage basins were identified, planning for potential regional detention areas was next.

“As the city develops, there is going to be a need to detain the stormwater so we don’t increase the flooding that already exists, and so that we don’t create flooding that is not there,” Cormack said.

The models developed showed 15 locations across the city suited for detention ponds.

“These are just recommended locations,we are not advising you go out and acquire easements yet, and these are really flexible on where they can be located,” Cormack said. “It’s really just kind of a conversation starter with developers.”

Examples of where detention ponds may be in the future include a pair of locations near downtown and Liberty Hill Elementary north of Main Street and south of the railroad tracks; on the north side SH 29 near CR 214; in front of the high school; on the western edge of City Park; along the west side of RM 1869 north of SH 29; and on the north side of SH 29 between US 183 and Sunset Ridge Drive.

The hope is that through this plan, site-based detention will not be the focus, as many developments won’t justify it on their own, but that the focus can be on a larger area and address the impact of numerous sites on an area overall.

In phase 1 of the city’s drainage master plan, K. Friese & Associates identified 17 problem areas in the city, which have been ranked based on criteria to include the impact on property, streets, overlap with other projects, funding sources and the need for outside entity coordination.

“We came up with 17 problem areas,” Cormack said. “We ranked them to determine how we would tackle these drainage issues throughout the city. Phase 2 is developing solutions on how we will address these issues throughout the city.”

The top five problem areas according to the rankings include Jenks Branch, downtown flooding, East Carson Avenue, Liberty Trails Apartments, and the City Park and County Road 200.