Floods are the costliest natural disasters in the United States. In fast-growing regions like Texas, a single storm can erase years of progress, derail municipal budgets, and threaten lives. The antidote is comprehensive floodplain analysis: an evidence-based process that maps present and future risks, guides smarter development, and unlocks smoother regulatory approvals. In this guide, you’ll learn what a floodplain study involves, which modeling tools deliver the best insight, and why partnering with Cardinal Strategies sets your project up for long-term success.
A floodplain analysis evaluates how rainfall moves through a watershed and where that water will spread during events ranging from the 2-year storm to the 500-year storm. In the context of Hydrologic and Hydraulic (H&H) modeling, floodplain analysis refers to the process of evaluating and mapping areas that are susceptible to flooding based on hydrologic and hydraulic data. This analysis is crucial for flood risk management, infrastructure planning, and environmental protection. Using hydrologic and hydraulic (H&H) modeling, engineers simulate everything from soil absorption and surface runoff to channel capacity and valley storage. The result is a set of digital maps and elevation data that reveal:
High-risk inundation zones
Expected water surface elevations and velocities
Impacts of future land-use changes
Critical infrastructure vulnerabilities
Municipalities rely heavily on flood studies as part of their planning, development, and emergency management strategies. These studies provide critical data and insights that help local governments make informed decisions to protect people, property, and infrastructure. Developers use them to optimize site layouts, size drainage infrastructure correctly, and avoid costly redesigns later.
Accurate floodplain boundaries allow planners to reroute roads, elevate critical utilities, and keep homes out of harm’s way. Fewer emergencies mean lower public-safety costs and faster disaster recovery.
Designing to real-world flood data helps projects clear FEMA and municipal reviews on the first submission—saving months of back-and-forth and thousands in rework.
Knowing precise inundation limits lets owners maximize developable acreage while still reserving natural overbank areas for flood storage or stream restoration and stabilization projects (stream-restoration-and-stabilization).
Properly sized detention ponds, culverts, and green infrastructure reduce maintenance costs, extend asset life, and protect property values.
LiDAR topography, survey topography, rainfall records, soil data, and land-use plans are gathered.
Field reconnaissance confirms structures, channel conditions, and potential bottlenecks.
Software such as HEC-HMS calculates watershed runoff for multiple storm frequencies and infrastructure scenarios.
Users can build models using various components (sub-basins, reaches, junctions, reservoirs).
Peak flows and timing are calculated for hydraulic modeling.
HEC-RAS is developed by the U.S. Army Corps of Engineers and is free to use. It utilizes a large user base with extensive documentation and tutorials making it an industry standard for hydraulic modeling.
Models 1D and 2D flow: Simulates both steady and unsteady flow conditions.
Handles complex geometries: Bridges, culverts, levees, ineffective areas, and more.
Works seamlessly with HEC-GeoRAS and other GIS tools for spatial analysis.
Enables floodplain mapping and visualization in geospatial formats.
Provides water surface profiles, velocity distributions, flood extents, and more.
Includes built-in tools for cross-section plots, profile plots, and animations.
Models are based on scientifically validated methods—making our narratives, tables, and figures credible and easy to understand for reviewers at all levels of government.
Accurate modeling results are essential for meeting FEMA, NFIP, and local permitting requirements. Clear reporting helps municipalities and developers work efficiently to improve conditions.
Whether you need a Conditional Letter of Map Revision (CLOMR) before construction or a final Letter of Map Revision (LOMR) upon completion, paperwork delays can stall projects for months. Cardinal Strategies handles the entire LOMC lifecycle:
Pre-application and Data Collection: Coordination with FEMA and local floodplain managers as well as collecting as-built survey plans
Digital Submittals: H&H models, workmaps, certified elevations, and proper documentation
Real-time comment tracking and swift resubmittals
Public notification support when required
Our relationships with reviewers—and our reputation for accurate models—translate into quicker approvals and fewer budget surprises.
Modern flood risk management is about more than passing inspection; it’s about leaving a healthier watershed for the next generation. Cardinal Strategies integrates:
Green detention ponds that double as community amenities
Stream-bank bioengineering using native vegetation and rock toe protection
Permeable pavement and bioretention to reduce first-flush pollution
Low-impact grading that preserves natural swales and groundwater recharge
These solutions protect property while supporting wildlife habitat, improving water quality, and boosting public acceptance.
"At Cardinal Strategies, we don’t just run models—we build them with precision. Every contour line, flow path, and cross-section in a Cardinal Strategies model is backed by detailed hydrologic and hydraulic analysis, field-verified data, and clear documentation. Our goal is to deliver technically sound results that clients can trust and developers can build on with confidence.”
—Michael Stone, Assistant Project Manager
Decades of Proven Experience
Our civil engineers have completed municipal-accepted studies across North Texas since 2014.
Regulatory Foresight
Continuous code monitoring keeps your design aligned with the latest FEMA, Texas Water Development Board, and city requirements.
Clear, Plain-Language Deliverables
We turn complex hydraulics into one-page executive briefs your council members and investors can digest in minutes.
Full-Service Partnership
From preliminary risk screens to final construction oversight, you’ll have one point of contact—and the confidence that nothing falls through the cracks.
Q: How long does a typical floodplain study take?
A: For an average watershed, expect 6–10 weeks, including data collection, modeling, and reporting for a municipal flood study. FEMA coordination can extend the process considerably as the federal review process is typically longer. Larger basins or public-meeting requirements may extend timelines.
Q: What storms should we model for climate resilience?
A: Most jurisdictions require some combination of the 2-year, 5-year, 10-year, 25-year, and 100-year storm. These are useful for comparing current infrastructure and understanding risk.
Q: Can floodplain limits change after construction?
A: Yes. New impervious areas or channel modifications can alter flood extents. Strict regulations from local and federal jurisdiction keep flood prone areas safe and effective.
A well-executed floodplain analysis is one of the smartest investments you can make. At Cardinal Strategies, we deliver the data, design insight, and regulatory confidence you need to build safely, sustainably, and in full compliance with local and federal standards.
Schedule a free 15-minute consultation →
Cardinal Strategies • Hydrologic & Hydraulic Modeling • Stormwater Engineering • Serving Municipalities & Developers Across North Texas