Federal Flood Control

Federal flood control is a massive, century-old program through which the U.S. Army Corps of Engineers builds and maintains levees, floodwalls, dams, channels, and other infrastructure to reduce flood damage. The program operates as a federal-local cost-sharing partnership: the federal government funds the bulk of construction, while state and local "non-federal interests" provide land, easements, and ongoing maintenance. See National Flood Insurance for the related insurance program.

Current Law (2026)

Parameter	Value
Lead agency	U.S. Army Corps of Engineers
Cost-sharing (construction)	Non-federal interests pay 5% during construction + provide all lands/easements/rights-of-way
Cost-sharing (maintenance)	Non-federal interests bear ongoing maintenance costs
Emergency repair fund	$25 million authorized (standing emergency appropriation)
Floodplain management	New structures in 100-year floodplain excluded from federal benefit calculations after July 1, 1991
Small project threshold	Projects under $3M federal share: flexible frequency/drainage analysis
Expedited action trigger	Areas with presidentially declared major disaster in preceding 5 years

Legal Authority

33 U.S.C. § 701 — Flood control generally (applies existing river/harbor improvement laws to flood control works; requires all flood control expenditures to follow standard government disbursement rules)
33 U.S.C. § 701a-1 — "Flood control" defined (establishes federal jurisdiction over flood control investigations and works)
33 U.S.C. § 701b-11 — Flood protection projects (authorizes specific flood protection construction projects)
33 U.S.C. § 701b-12 — Floodplain management requirements (imposes floodplain management conditions on federal flood control projects)
33 U.S.C. § 701b-15 — Non-Federal plans to provide additional flood risk reduction (allows state and local governments to propose supplementary flood risk measures)
33 U.S.C. § 701b-16 — Management of flood risk reduction projects (establishes management framework for federal flood projects)
33 U.S.C. § 701c — Rights-of-way, easements (requires non-federal interests to provide all lands, easements, and rights-of-way at no cost to the federal government before construction begins; requires local assurances of maintenance and operation)
33 U.S.C. § 701n-3 — Permanent measures to reduce emergency flood fighting needs (targets communities subject to repetitive flooding for permanent infrastructure solutions)
33 U.S.C. § 701t — Emergency fund for flood damage (authorizes $25 million for repair, restoration, and strengthening of threatened or destroyed levees and flood control works)
33 U.S.C. § 2213 — Flood control cost sharing (establishes the 5% non-federal construction cost share plus land/easement/right-of-way requirements)
33 U.S.C. § 2289 — Urban and rural flood control frequency (allows flexible analysis without regard to flooding frequency for projects under $3M federal share)
33 U.S.C. § 2318 — Flood plain management (excludes new or substantially improved structures built in the 100-year flood plain after July 1, 1991 from federal project benefit calculations)
33 U.S.C. § 2341 — Expedited actions for emergency flood damage reduction (directs the Secretary to expedite planning, design, and construction for areas that suffered a presidentially declared major disaster from flooding within the preceding 5 years)

How It Works

The federal flood control program — closely linked to the National Dam Safety Program and federal navigation authority under the Rivers and Harbors Act — dates to the Flood Control Act of 1936, which declared flood control a "proper activity of the Federal Government." The Army Corps of Engineers designs, builds, and in some cases operates flood control infrastructure — levees, floodwalls, flood-control dams, diversion channels, and flood gates — across the country.

The cost-sharing framework is the program's backbone. Non-federal interests (typically state agencies, counties, or local levee districts) must provide all lands, easements, and rights-of-way needed for a project at no cost to the federal government. They must also pay 5% of construction costs during the building phase and agree to operate and maintain the completed project in perpetuity. These are binding conditions — no federal money flows until local assurances are locked in.

The floodplain management provisions create an important feedback loop. After July 1, 1991, any new or substantially improved structure built in the 100-year floodplain with a first floor below the 100-year flood elevation cannot be counted in the benefit calculations that justify federal flood projects. This discourages building in flood-prone areas by making it harder to justify federal protection for newly constructed floodplain development. A special exception exists for counties substantially located within the 100-year floodplain — otherwise, some rural counties would be unable to develop at all.

For communities hit by repetitive flooding, the law authorizes permanent measures to reduce emergency flood-fighting needs. Rather than repeatedly deploying temporary defenses during each flood event, the Army Corps can build permanent infrastructure for communities caught in a cycle of recurring flood damage.

The emergency fund ($25 million standing authorization) gives the Army Corps flexibility to respond quickly when levees or flood control works are threatened or damaged by floods — repairs that can't wait for the normal appropriations process.

For smaller projects (under $3 million federal share), the Secretary has flexibility to evaluate flood damage reduction measures without regard to standard flooding frequency, drainage area, and runoff calculations. This allows practical solutions for small communities that might not meet traditional benefit-cost thresholds.

How It Affects You

If you're a homeowner behind a levee or living near a federal flood project: Your flood insurance rates and FEMA flood map designation depend partly on whether the levee protecting your area is "accredited" — meaning it meets USACE standards and has been formally certified to the NFIP. An accredited levee can remove your neighborhood from the Special Flood Hazard Area (SFHA) on FEMA's Flood Insurance Rate Maps (FIRMs), eliminating mandatory flood insurance purchase requirements. If your levee's accreditation lapses — because of deferred maintenance, discovered deficiencies, or a decertification process — your property can be remapped back into the SFHA, triggering mandatory insurance requirements that can cost $1,000–$3,000+ per year. Check your levee's status at the National Levee Database at nld.usace.army.mil, maintained by the Army Corps. If your levee is listed as "not accredited" or under review, contact your local flood control district and FEMA regional office to understand the timeline and what's being done. Don't assume your county will automatically maintain the infrastructure that protects your home's insurance status. You can check your property's current FEMA flood zone at the Flood Map Service Center at msc.fema.gov — searching by address takes about 30 seconds and shows your current flood zone, FIRM panel, and when the map was last updated.

If you're a local official or taxpayer funding a federal flood project: Federal flood control is not free to local governments. The standard cost-sharing formula requires non-federal sponsors to contribute 25–50% of project costs for most authorized projects — covering land acquisition, easements, relocations, and perpetual operation and maintenance (O&M). For a $50 million project, a local sponsor might owe $12.5–$25 million upfront plus all future O&M costs. These obligations are formalized in Project Cooperation Agreements (PCAs) with USACE. Local governments typically fund their share through special assessment districts, sales tax measures, stormwater utility fees, or general obligation bonds. Before committing to a federal partnership, get a full lifecycle cost estimate — the 50-year O&M obligation often exceeds the initial construction share. The Trump administration's 2025 cancellation of FEMA's BRIC program (which funded pre-disaster mitigation grants) has increased pressure on USACE flood control as the primary federal investment pathway. Track Army Corps project status and WRDA authorizations at usace.army.mil/Missions/Civil-Works/Project-Planning.

If you're a farmer or rural community seeking small-scale flood protection: USACE's Continuing Authorities Program (CAP) was built for situations that wouldn't attract a congressional earmark. Section 205 of the Flood Control Act (33 U.S.C. § 701s) authorizes USACE to design and build small flood control projects up to $10 million total federal cost without separate congressional authorization — the practical entry point for small rural communities. Section 14 authorizes emergency streambank and shoreline protection for public facilities at up to $1.5 million per project. To initiate a CAP project, your local government or drainage district submits a request letter to the nearest USACE district office; USACE conducts a feasibility study and, if the project qualifies, designs and builds it with local cost-share. Find your USACE district at usace.army.mil/Locations. For agricultural land specifically, USDA's Emergency Watershed Protection (EWP) Program administered by NRCS provides a parallel path for drainage and watershed protection after disasters at nrcs.usda.gov/programs-initiatives/ewp-emergency-watershed-protection-program.

If you're developing land or building in a floodplain: Federal flood control projects are not designed to justify or protect new development built knowingly in a flood hazard area. Structures built below the 100-year base flood elevation (BFE) after 1991 don't count in the economic benefit-cost analysis that justifies federal flood protection investments — so you cannot expect federal infrastructure to follow your development into a known floodplain. Beyond federal policy, FEMA's NFIP regulations (44 CFR Part 60) require local communities participating in NFIP to impose minimum construction standards in SFHAs — including building the lowest floor at or above BFE. Violations can result in flood insurance being unavailable or rated at dramatically higher "non-compliance" rates ($6,000–$10,000+ per year in some cases). Before breaking ground in any flood-prone area, check the Flood Map Service Center at msc.fema.gov, consult your local floodplain administrator (every NFIP-participating community has one — find them through your county's building or planning department), and get a flood insurance rate estimate at floodsmart.gov before committing to a purchase or construction plan.

State Variations

While the federal flood control program is nationwide, implementation varies significantly by region:

The Mississippi River system has its own specific statutory framework (Mississippi River Commission, extensive levee systems)
States maintain their own levee safety programs with varying levels of oversight
Some states (California, Louisiana) have sophisticated levee authorities with dedicated funding; others rely more heavily on local levee districts
State floodplain management laws interact with federal provisions — many states impose stricter requirements than the federal baseline
Local cost-sharing capacity varies enormously, affecting which communities can participate in federal projects