The City of Fulshear commissioned a Master Drainage Plan (MDP) to be conducted by Costello, Inc. to study flooding issues throughout the City. The MDP focused upon two main unnamed neighborhoods along Bois D’Arc Lane and Red Bird Lane. A high-level evaluation was also completed for the downtown area of the City.

To complete a detailed, site-specific analysis and more efficiently evaluate the overall impacts within the Fulshear Creek and Flewellen Creek watersheds, hydrology for the project was evaluated utilizing XP-SWMM.
For the localized evaluations, the Natural Resource and Conversation Service (NRCS) unit hydrograph method was used. To complete the watershed evaluations, the Clarks unit hydrograph method was used in accordance with the process required by the Fort Bend County Drainage District criteria.

The hydraulic analysis for the project was completed in XP-SWMM using a 2D unsteady state analysis to evaluate existing and proposed conditions of localized systems. To increase the accuracy of the analysis and reduce run times, nested LiDAR grid data was utilized for areas that required more detail. HEC-RAS was used to evaluate riverine flood from the adjacent creeks.

Within the City’s downtown area, initial high-level recommendations were provided to develop a roadmap for drainage improvements and help identify opportunities and constraints. Obstacles encountered included existing structures built over a trunk storm sewer, inadequately sized roadside ditches and driveway culverts, and the lack of city-owned drainage easements or rights-of-way to construct drainage improvements and outfall to existing channels.

As part of the project, public meetings were held to present the existing conditions analysis, initial proposed improvements, and receive input from residents. Input received during the public meetings from discussions with City staff and the City Mayor was utilized to finalize evaluations and provide final recommendations. Consideration was given to the potential phasing of construction to help match available City funds. Final recommendations were presented to the Mayor and City Council during a regularly scheduled City Council Meeting.