An amendment to Killeen’s drainage design manual narrowly gained council approval this week, with opposing council members noting they were “uncomfortable” with the changes being made.
Changes made to the document include raising the allotted amount of water above the top of the curb from zero to 4 inches, increasing how fast water could travel to drain from roadways from 4 feet per second to 7 feet per second and defining what an intersection is.
Kristina Ramirez, environmental services director, said the changes were based on erosion factors and “general engineering practices.”
“By allowing that water to go back above to top of curb, we felt that we needed to put additional safety factors in place,” she said.
The drainage manual governs the planning and design of drainage infrastructure in the city.
Ramirez said the definition change to intersection regards how far around the corner of a roadway needed to be considered an intersection. It controls the amount of water acceptable in the intersection for vehicles to travel safely through.
Ramirez said when the ordinance was adopted in 2011, it was developed by examining data, but the city “really hadn’t been tracking” the cumulative effect of all the changes made to the manual at that time.
“Since it was adopted, we started seeing plans come in and what the controlling factors were and where there might be areas for change,” she said. “This is one of the first areas that we looked at.”
She said emergency vehicles were taken into consideration when considering upping the amount of water allowed above the top of the curb, with police cruisers representing everyday vehicles because they have the lowest clearance from the street.
“We found that most of our emergency vehicles have 6 to 8 inches of clearance under them,” Ramirez said. “So, 4 inches of standing water is still allowable underneath our emergency vehicles during a storm event.”
She said city officials, the school district, engineers, developers and the public were involved in meetings to discuss the changes.
The proposal passed by a 4 to 3 vote. Councilmen Steve Harris, Jonathan Okray and Terry Clark voted against the amendment. “I am very uncomfortable with 4 inches over the curb, even with concessions with the intersection,” Clark said. “I would like to find a number somewhere between 1 and 3 (inches) that would make me more comfortable. I would like this to go back to the stakeholders and give more consideration to pedestrian traffic and do some real analysis of what this means.”
Harris said he thinks the city is in a “catch 22.”
“Where do we find that balance where we try to look out for the emergency vehicles but at the same time look out for the pedestrians and the homes of the citizens to make sure they don’t get flooded as well?” he said. “Where is our happy medium there?”
Ramirez said changes won’t be made to existing infrastructure, but the amendment to the drainage design manual will affect new construction.