Title
Consider and take action on a resolution authorizing a professional services agreement with Cobb, Fendley & Associates, Inc. for design work related to the Robinson Bayou Watershed Drainage Study (DR2307C) in an amount not to exceed $148,410 (Executive Director of Development Services)
Background:
Approval of this resolution will authorize the City Manager to enter into an agreement with Cobb, Fendley & Associates, Inc. (C-F) for a drainage study in the Robinson Bayou Watershed in an amount not to exceed $148,410.
The City’s 2-D Drainage Model Project (completed in 2021) found that there was ponding at the upstream end of Robinson Bayou’s West Tributary, specifically in the St. Charles Street area along with a series of homes along Power and Illinois Avenue experiencing repetitive losses in major storm events. This study also found that Robinson Bayou overtops its banks at a 25-yr rainfall event and areas within the watershed routinely experience parking lot and street flooding. In tidal conditions (storms with surge elevations of 12’ or higher) will cause Robinson Bayou to overtop its bank during a 2-yr storm.
The Robinson Bayou Watershed drainage study will take the findings from this 2021 study a step further by performing an analysis of the existing condition of Robinson Bayou to determine flows conveyed to the bayou from contributing areas within the watershed and determine resultant water surface elevations using computational hydrologic and hydraulic modeling software. An existing condition model will be created in locations where it is determined necessary to better understand how connectivity functions between local street storm water conveyance and flow within the bayou.
C-F will then perform a proposed condition analysis by creating alternative solutions to the problem areas. Such solutions include channel improvements, roadway conveyance improvements, local detention and/or regional detention to help reduce inundation in higher intensity...
Click here for full text