Case Study: Houston Flood Control Project Design Underestimation Causes Structural Issues (2018)

Project Overview
• Name: Houston Flood Control Channel Expansion
• Location: Houston, Texas
• Year: 2018
• Project Size: $350 million
• Scope: Widening and deepening of flood control channels and levees
• Lead Agencies/Contractors: Harris County Flood Control District /

Category of the Issue, Problem, or Challenge
• Design
• Hydrological & Structural Engineering

Summary of the Issue, Problem, or Challenge
Hydrological and structural design underestimated peak flow rates and soil saturation impacts, leading to instability in levee slopes and channel walls during construction. This necessitated redesign and stabilization measures to ensure safety and performance.

Root Cause Analysis

• Outdated or incomplete hydrological data used in design.
• Insufficient geotechnical analysis of soil behavior under saturated conditions.
• Underestimated design safety factors for slope stability.
• Lack of adaptive design review based on ongoing field monitoring.

Impacts Due to the Issue, Problem, or Challenge
• 4-month delay due to slope stabilization and redesign work.
• Additional costs of $5 million for remedial construction.
• Increased risk of future flood damage if not properly addressed.

Corrective Actions Taken

1. Updated hydrological models with recent storm data.
2. Conducted detailed soil testing and revised slope stability designs.
3. Increased design safety factors for critical structures.
4. Implemented real-time monitoring of slopes during construction.

Lessons Learned

• Hydrological and geotechnical data must be current and comprehensive.
• Safety factors should be conservative in critical flood control infrastructure.
• Field monitoring allows adaptive responses to unforeseen conditions.
• Collaborative reviews between hydrologists, geotechnical, and structural engineers are essential.

Audit & Prevention: Project Control Questions to Ask on Future Projects to Help Control the Situation

• Is hydrological data up to date and representative of extreme events?
• Are geotechnical analyses thorough and validated by field testing?
• Are design safety factors adequate for soil and slope stability?
• Is construction monitored to allow adaptive design changes?