Due to flooding problems during previous flood events, the City of Harker Heights authorized Walker Partners to study the Trimmier Creek Tributary from FM 2410 to Carl Levin Park. Walker Partners was charged with determining the probable flood risk of the Trimmier Creek Tributary under present day and future development conditions, and to propose drainage improvements to reduce the floodplain elevations and the resulting flood hazards. Walker Partners studied the 10, 50, and 100-year storm events because they have special significance for floodplain management and for flood insurance rates.

Walker Partners used Corps of Engineers software HEC-HMS for the hydrologic analysis and HEC-RAS to determine water surface elevations for the Trimmier Creek Tributary Study. All vertical elevations were referenced from the North American Datum (NAVD) of 1988.

The results of this study indicated that the existing 100-year floodplain was less intrusive than was depicted on the existing FEMA Flood Insurance Rate Map (FIRM). Walker  Partners surveyed the finished floor slab elevations of the residences that were adjacent to the Trimmier Creek Tributary and found that all residences were above the 100-year water surface elevation even though the properties were somewhat inundated.