← Platr suite

Platr Surfacr · iOS · McCracken County, KY

Data pipeline live · iOS UI in progress

Is this land at flood risk based on where the water actually goes?

FEMA’s flood map is a legal instrument. Surfacr adds the terrain. Tap any parcel to see the hydraulic reality beside the regulatory boundary — and find out whether they agree.

Paducah sits at the confluence of the Ohio and Tennessee Rivers. Flood dynamics here are not theoretical. The city has been catastrophically flooded multiple times in the last century, and the relationship between water and land in McCracken County is a question with real money and real lives attached to it.

FEMA’s Special Flood Hazard Area maps answer one version of that question — the version that determines flood insurance rates and building permits. They are drawn from hydraulic models that are often 20+ years old, at resolutions that can’t resolve a drainage swale or a culvert-induced backwater. Surfacr adds a second answer: what the actual 2-foot-resolution terrain says water will do on that specific parcel.

FEMA vs. real terrain — where the gap lives

Surfacr scores every parcel by how high it sits above the nearest stream — the simplest honest signal of flood exposure. Low above the stream means real hydraulic connection and real inundation risk; high means the water flows somewhere else before it could reach you. That score sits next to FEMA’s official zone, side by side, on every parcel.

The critical gap: FEMA’s flood zones frequently disagree with what the actual terrain says in McCracken County. The 2-foot terrain layer resolves drainage paths that a coarser national-scale model completely misses — swales, cut channels, farm ditches. Properties FEMA shows outside the flood zone can sit low enough above a real drainage channel to have meaningful exposure. Properties insidethe FEMA zone can sit high enough on the local divide to have no credible flood path. The disagreements are where uninsured risk lives — and where insurance gaps hide.

The Ohio/Tennessee confluence at 37.0690°N, 88.5836°W is the geographic anchor — two major rivers meeting at the county seat, with Massac Creek draining the middle of the county into the Ohio upstream. The drainage here is complex enough that a simple polygon overlay misses it entirely.

The data, by layer

2 ft
terrain
Full
county coverage
Live
FEMA comparison
Every
parcel scored
2-foot terrain
State-flown ground elevation, full McCracken County coverage. The resolution that reveals what national-scale models miss.
Flood exposure score
How high every parcel sits above the nearest stream — terrain-based flood exposure, independent of FEMA’s models.
FEMA flood zones
The official Special Flood Hazard Area polygons (Zone A, AE, X). The regulatory baseline Surfacr compares against.
Stream network
High-resolution stream lines — Ohio River, Tennessee River, Massac Creek, and every named and unnamed tributary. The reference frame for the flood-exposure score.
Past flood events
Historical floods in McCracken County — dates, damage estimates, and affected areas from federal records. Ground truth against the model.
Wetlands
National wetland polygons. Presence is a flood-exposure indicator and a buildability constraint independent of the insurance designation.
Fire/EMS stations
Federal fire and EMS locations. Emergency response time for a flood-affected parcel is a question Surfacr can answer once the parcel’s risk profile is established.
Parcel overlay
Walk’s legal stack (boundary, owner, assessment, property class) joined to every Surfacr query. Who owns the at-risk parcel and what it’s worth are part of the same answer.

Why open data is the contingency anchor

Surfacr is the only app in the suite that runs entirely on federal and state open data — zero county-records dependency for the flood and terrain layer. That means it ships regardless of parcel data licensing status in any given county. If a county’s PVA record is locked behind an access agreement, Surfacr still gives you the terrain-derived flood exposure for every parcel in it. The parcel context (owner, assessment) is additive when available.

The state’s 2-foot terrain coverage spans the entire Jackson Purchase region, not just McCracken. Flood risk for Ballard, Graves, Livingston, Marshall, Trigg, and Lyon counties runs through the same pipeline with no new data to acquire.

What’s not in there yet

Want the flood layer for your county? Fork Development Corp — info@jays.bio

— end —