eHT is providing project management, design and construction administration for the replacement of aging roadway surface with full depth base, as well as drainage improvements along College Hills Boulevard (CHB). The project includes the rehabilitation of water and sewer utilities, roadway design, drainage evaluation and improvements, right-of-way verification, design survey, geotechnical investigation and the development of plans and specifications.

Originally constructed in the 1970s, College Hills Boulevard crosses the Red Arroyo drainage basin which frequently experiences roadway closures due to floodwaters overtopping the roadway. eHT has determined that raising the roadway out of the 100-year floodplain would require upwards of 4 feet of vertical fill, significant re-grading of adjacent streets, and mitigation of multiple other flooding considerations. eHT is now assisting the City with development of solutions through a Master Drainage Plan and the City has applied for grant funding through the FHA BUILD program in order to fund drainage improvements.

Drainage analysis completed by eHT as part of the project has shown that the primary cause of flooding of CHB is the low and flat roadway profile across the Red Arroyo floodplain. The existing drainage structures under CHB are undersized and contribute little to preventing the roadway from overtopping during frequent rainfall events.  Cost analysis performed by eHT showed that raising the profile of CHB across the Red Arroyo out of the floodplain exceeds the budget due to the vertical fill required to raise the roadway and the impacts on intersecting streets, commercial driveways and existing adjacent structures. Implementation of an underground drainage system along CHB was evaluated but large flows and high water levels within the Red Arroyo limit the effectiveness of this system without some form of upstream improvement. In order to meet the City’s budgeted timeline while drainage solutions are developed and evaluated, eHT is preparing a utility replacement package to bid prior to roadway improvements.