Waller County Master Drainage Plan
Waller County was awarded a grant to perform a County-Wide Master Drainage Plan under the General Land Office (GLO) Community Development Block Grant - Mitigation program (CDBG-MIT) associated with recovery from Hurricane Harvey
About the Project
This project will focus on recovery and resiliency through detailed analysis, modeling, and mapping of existing flood risk and developing proposed alternatives to provide long term risk reduction within the community. The study will include evaluation of drainage patterns, topography review, engagement efforts, identification of problem areas, and recommended priority of projects for future flood mitigation.
The contract between the GLO and Waller County was executed on April 4, 2024 and the Master Drainage Plan (MDP) was began by LJA Engineering, Inc. (LJA) on April 14, 2024. The project is estimated to be completed by Winter 2025.
The MDP is focused on four (4) main phases, including Project Management, Data Collection, Alternative Analysis and Reporting.
Project Management
The MDP is scheduled to take 1.5 years to complete with Data Collection taking 6 months, the modeling analysis to take 12 months and the reporting to take around 6 months.
Data Collection
Initial schedule is to conduct data collection for the first 6 months, including review of existing studies and models, identification of known problem areas, and review / update to the Design Criteria Manual. Conduct a data gap analysis to identify incomplete or missing data and a strategy to overcome.
Alternative Analysis
Review of available models from existing sources across the County, including FEMA Effective models, available master plans for local cities / MUDs, and regional studies from Brazos River Authority and/or TWDB Base Level Engineering (BLE) models. Develop detailed Hydrologic and Hydraulic models for areas identified in the gap analysis to provide county-wide coverage and perform alternative analysis for proposed improvements, including cost estimates and Benefit-Cost Analysis (BCA).
Plan Development
The development of the MDP will include interim technical memos to Waller County for cursory review for Data Collection, Existing Conditions, and the Alternative Analysis efforts. The final report will be a compiled package of these Technical Memos for review by the County and the GLO and will include any feedback or comments received by the County and stakeholders.
Get Involved
As part of this MDP, the County and LJA are looking for anything that would help us understand the current flood risks and problem areas across the County. This web portal is being set up to assist with the submittal of any historical information that might help us identify problem areas, validate our modeling efforts, and focus in on potential causes and solutions to these issues. The following items will be extremely valuable for our efforts going forward:
- Photos with date and/or time stamp are most beneficial to help with calibration and validation.
- High Water Marks or ponded depths also help correlate with technical drainage modeling results.
- Riverine models (hydrology and hydraulic) such as: HEC-HMS / HEC-RAS / InfoWorks
- Drainage system models (hydrology and hydraulic) such as: InfoWorks / XP-SWMM / EPA-SWMM / GeoPak-Open Roads / Excel
- GIS alignments and/or physical changes for development or topographic improvements
- Current or proposed drainage projects
- Areas of concern and/or of historic flooding issues (Intersections, structures, etc.…)
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