In the City of Harker Heights, Indian Trail and Verna Lee Boulevard are vital transportation corridors. Both of these thoroughfares were being impaired during rainfall events and to a similar extent, Antelope Trail, due to excessive runoff being carried into the street. Both Verna Lee Blvd. and Antelope Trail had low water crossings that required the City to close them to through traffic during high rainfall events. These roadways also happened to be the principal routes of KISD buses carrying students to and from school, as well as students walking to and from school. Original development in the drainage area was woefully inadequate and the City sought a solution to the problem.
The City of Harker Heights needed a consultant that possessed the knowledge and expertise to remedy these issues, and Walker Partners’ personnel exceeded the criteria required for the job.
The primary goal was to reduce the runoff crossing Verna Lee Blvd. and Antelope Trail such that the streets could remain open to traffic during storm events. The runoff had to be collected and conveyed within an underground conduit to relieve the necessity of the streets to carry all the drainage. The only outlet available for the drainage was the existing box culvert and earthen ditch crossing Indian Trail north of the Indian Trail and Antelope Trail intersection.
The extent of the drainage area was determined from the City’s existing topographic maps as well as field reconnaissance. Once the drainage area was defined, Walker Partners modeled the hydrology and the necessary hydraulics to size the storm drainage conduit which would serve as the major artery. The reinforced concrete box culvert was designed to discharge directly into the existing culvert crossing Indian Trail and extended south to near Verna Lee at which point it branched with a 48 in. diameter RCP conduit and looped into Verna Lee at its existing low water crossing. Numerous 20 ft. curb inlets were used to intercept water and convey them to the main storm drain running south within the street surface of Indian Trail. Numerous conflicts with existing wet and dry utilities were overcome during construction as Walker Partners had to design “on the fly” to keep the project progressing to completion. The City’s Public Works Staff worked hand in hand with Walker Partners in these efforts.
It is said that a picture paints a thousand words. The original picture of this problem during storm events was one of Indian Trail carrying runoff in excess of the top of the curb. Vehicles navigating the street sent cascades of water up and onto the adjoining right of way while moving at less than 10 mph. Both Verna Lee Blvd. and Antelope Trail had barricades up at the low water crossings that prevented residents from getting to and from their residences in a normal manner. The completed project picture is much improved. Indian Trail is now largely devoid of excess drainage, and vehicles travel at a normal pace while no barricades or closures to through traffic are necessary on either street. Today, residents and emergency vehicles can easily navigate the project area during storm events.
completion date: 2011
location: Harker Heights, Tx