USACE Levee Flood Risk Screener — National Levee Database

This actor answers the question a FEMA flood-zone lookup cannot:

"Is there a levee between this property and the water — and can I actually trust it?"

It screens locations (or a state/county inventory) against the US Army Corps of Engineers National Levee Database (NLD) — the authoritative federal registry of ~30,000 leveed areas — and computes an editorial levee risk score from the attributes that actually predict levee failure risk: FEMA accreditation status, overtopping chance, PL 84-99 rehab-program enrollment, warning-system presence, and mapped egress routes.

This is deliberately not a flood-zone lookup. A property can sit in FEMA Zone X (no flood insurance required) purely because it's "protected" by a levee FEMA itself rates Non-Accredited — meaning FEMA does not actually trust that levee to hold back a 1%-annual-chance flood. That gap is the whole point of this actor.

Who it's for

• Insurance & underwriting teams — screen a book of insured properties for hidden levee-dependent flood exposure that flood-zone data alone misses.
• Real-estate & title due diligence — check a parcel before close; a Non-Accredited levee is a material disclosure risk.
• Lenders & mortgage risk — flag levee-protected collateral that FEMA maps understate.
• Municipal & emergency management — rank levees in your county by risk to prioritize inspection and rehab funding requests.
• AI agents — a clean, chainable "levee check" tool: coordinates in, structured risk verdict out.

Two modes (auto-detected from input)

1. Assets mode — screen specific points

Set assets (a list of {lat, lon, label}). The actor runs a server-side point-in-polygon query against every NLD leveed-area polygon for each point. One row out per asset — assets with no levee overlap are still returned (behind_levee: false) so a batch never silently drops rows.

{
  "assets": [
    { "lat": 45.903, "lon": -111.53, "label": "Gallatin County, MT (Madison River levee)" },
    { "lat": 38.075, "lon": -102.28, "label": "Granada, CO (Granada Right Levee)" }
  ]
}

2. Inventory mode — rank levees in an area

Leave assets empty and set states and/or counties instead. The actor pages the NLD, computes a risk score for every matching leveed area, and outputs the top maxResults ranked by leveeRiskScore descending — the worst levees in your area of interest, first.

{
  "states": ["CO"],
  "counties": [],
  "maxResults": 100
}

Output fields

Field	Meaning
asset_label, asset_lat, asset_lon	Your input point, echoed back (assets mode)
behind_levee	True if the point falls inside a mapped leveed area (assets mode)
leveed_area_count	How many leveed-area polygons contain the point (assets mode)
rank	1 = highest risk in the fetched set (inventory mode)
system_name, system_id	Official NLD system name / ID
states, counties, community_names	Where the leveed area sits (systems can span multiple states)
sponsors, sponsor_type	Who owns/maintains the levee
fema_accreditation_rating	FEMA's certification status for the levee
non_accredited_flag	True unless the rating is exactly "Accredited Levee System"
overtopping_ace	Parsed annual chance of overtopping, when known
rehab_program_status	PL 84-99 federal rehab enrollment: Active / Inactive / Not Enrolled
warning_system	Whether a flood warning system is documented
egress_number	Mapped evacuation routes out of the leveed area (0 = none on file)
leveed_area_sq_mi, flood_sources	Size and the water body it protects against
leveeRiskScore	0-100 editorial composite risk score (see below)
checked_at, disclaimer, source_url, error	Run metadata and advisory notice

Invalid asset points produce an error row and the run continues — one bad coordinate never fails a large batch.

How leveeRiskScore is computed

leveeRiskScore is an editorial model, not a FEMA or USACE figure:

leveeRiskScore = accreditationFactor x overtoppingFactor x rehabFactor
                 x warningBoost x egressBoost   (scaled to 0-100)

• accreditationFactor — Non-Accredited scores highest, Provisionally Accredited (PAL) next, unclear/no-info text next, Accredited lowest.
• overtoppingFactor — derived from the NLD's reported annual chance of overtopping; unknown/missing chance is treated as elevated risk, not neutral, because a levee with no data on file is not one you can verify.
• rehabFactor — Active PL 84-99 rehab enrollment (a known, currently flagged deficiency) scores higher than Not Enrolled.
• warningBoost — a documented flood warning system reduces the score; no/unknown warning system boosts it.
• egressBoost — zero mapped evacuation routes boosts the score the most; 1 route is a smaller boost; 2+ routes add nothing.

Missing data is deliberately treated as risk-elevating throughout — a levee the NLD has no accreditation, overtopping, or egress data for is exactly the kind of levee that hasn't been checked recently, which is itself a risk signal.

This is not a flood-zone lookup or engineering certification. Confirm any insurance, lending, or life-safety decision against official FEMA flood maps and a licensed engineer.

Data source

USACE National Levee Database, "Leveed Areas" layer (ArcGIS FeatureServer, geospatial.sec.usace.army.mil/dls/rest/services/NLD/Public/FeatureServer/16). Keyless, official, and free — you pay only for the records this actor returns.

Use as an MCP tool

This actor is exposed via mcp.apify.com — AI agents (Claude, Cursor, etc.) can call it as a levee-exposure verification tool. The input schema (lat/lon/label list, or states/counties) and field-level output descriptions are designed to be read and chained by agents: geocode an address upstream, screen it here, branch on behind_levee / leveeRiskScore downstream.

FAQ

How do I check if my property is behind a levee? Geocode the address to lat/lon (any geocoder), pass it in assets, and read behind_levee and leveeRiskScore on the row.

Is a FEMA flood-zone "X" (no insurance required) always safe if there's a levee? No. FEMA can zone land as protected by a levee it separately rates Non-Accredited — the levee doesn't meet FEMA's engineering standard, but the flood-zone map hasn't been updated to reflect that. Check fema_accreditation_rating and non_accredited_flag directly; don't rely on flood-zone letter alone.

What does leveeRiskScore: null with behind_levee: false mean? The point is not inside any NLD-mapped leveed area — no levee-dependent risk to score from this data source. It says nothing about general flood risk.

Why might a point I expect to be "behind a levee" come back behind_levee: false? The NLD only maps levees the Corps has surveyed and digitized; some small, private, or unmapped levees aren't in the database yet. This is a screen against the federal registry, not a guarantee of ground truth.

Can I rank all the levees in my county? Yes — leave assets empty, set states: ["CO"] and counties: ["Prowers"], and the top maxResults leveed areas by leveeRiskScore come back ranked.

Why is overtopping_ace sometimes null even though the levee has data? The NLD itself reports "Unknown" for many systems — that's parsed to null and is treated as an elevated-risk input in the score, not a data gap on our side.