GBA completed a Preliminary Engineering Study (PES) to investigate the flooding of Nieman Road and businesses along Tributary 63 of Turkey Creek. After the PES was complete, GBA worked with Johnson County Stormwater Management Program (SMP) to secure funding for culvert and creek channel improvements. GBA’s mission was to:
- Eliminate 100-yr storm flooding of adjacent businesses
- Increase culvert capacity at Nieman Road
- Reduce the 100-yr storm flood depth to less than 7 inches at Nieman Rd
GBA worked through several alternatives and hydraulic evaluations with the city before finalizing a plan to remove the adjacent businesses from the 100-yr floodplain. Central to the design was the phased replacement of the existing two-cell reinforced concrete box (RCB) with a larger 3-cell RCB. In addition, retaining walls were used along the creek to provide bank protection to tightly spaced adjacent businesses and to improve hydraulic capacity. GBA completed the floodplain development permit and obtained a Corps of Engineers Nationwide Permit.
The innovative retaining wall solutions allowed for the walls in close proximity to businesses and parking lots to be constructed without interrupting their daily business traffic. In total, 15,000 sq. ft. of retaining wall was constructed with heights up to 22 feet and 1,600 linear feet of drilled shaft foundation.
Coordination with utilities, property owners and other consultants working on the “Nieman Now” project were all crucial to project success. Gas, sewer, power and phone were all coordinated and relocated as needed. Close coordination with affected property owners kept the project moving forward. GBA provided full construction services which included field observation of drilled shafts, retaining walls, RCB, roadway components, channel grading, riprap placement and final seeding and sodding.
This innovative project was awarded the KC ASCE 2018 Civil Engineering Project of the Year.