Project Summary

Manchester-Boston Regional Airport has identified capacity concerns within the closed drainage system located beneath long-term parking Lot C, which during recent high intensity storms has led to surcharging of catch basins and ponding water. Hoyle Tanner evaluated the hydraulics of this drainage system, identified likely capacity issues, and provided recommendations for improvement.

The 24.2-acre study area watershed consisted of predominately paved parking lots and buildings and conveyed stormwater through a large retrofitted closed system that has been altered numerous times during continued airport redevelopment. Hoyle Tanner prepared a hydraulic model of the closed drainage system and then calibrated it to recent storm events which allowed us to evaluate the Hydraulic and Energy Grade Lines of the system and identify problem area.

Hoyle Tanner investigated several improvement alternatives and recommended a replacement and upsizing of approximately 1,300′ of 24″ pipe with 36″ R.C. pipe to improve the systems hydraulic capacity.