Why CULVERT
The USGS identified roughly six million CONUS road-stream crossings by intersecting road lines with hydrography datasets, using 500,000 field observations for validation. Built for historical climates, this critical infrastructure is highly vulnerable to extreme precipitation, sediment-laden floods, and debris flows, threatening safety, economies, and aquatic passage. Since manually inspecting six million crossings is impossible, agencies need CULVERT: an automated hydro-geospatial decision-support system that flags at-risk locations, prioritizing inspections, restoration, and resilient redesign.
Peak storm flows exceed the culvert’s hydraulic capacity, overtopping and washing out the road crossing.
Rainfall-driven hillslope erosion (RUSLE) delivers sediment that aggrades and plugs the culvert inlet.
Saturated sediment and woody debris surge down steep channels and choke the crossing.
Channel widening and bank failure undermine the culvert and its road embankment.
Required datasets are integrated through open, reliable data APIs across the continental U.S.
If you don’t have crossing locations, the tool automatically generates candidate culvert sites and assesses them.
Assess risk at spatial resolutions up to 1 m or submeter scale, with temporal resolution down to 1 hour.
A pre-field risk assessment that prioritizes limited maintenance budgets and informs climate-resilient sizing — on all lands, not just federal property.
What CULVERT evaluates
Road–stream crossings fail in different ways depending on the watershed, climate, and disturbance history. CULVERT delineates each crossing’s contributing watershed and models the drivers below to flag the culverts most at risk — a pre-field risk assessment so limited inspection and maintenance resources go where they matter most.
From a digital elevation model to a culvert-by-culvert vulnerability report — a pre-field risk assessment with watershed delineation plus hydrologic and hydro-geomorphic analysis, all in the browser.
Slope failures in the contributing watershed that mobilize large volumes of sediment toward the crossing.
Slope instability in recently burned watersheds where fire has weakened root cohesion.
Elevated runoff and soil loss from hydrophobic, vegetation-stripped burn scars.
High-magnitude debris flows triggered by storms over freshly burned terrain.
Peak-discharge estimation driven by downscaled CMIP6 climate-model scenarios, for forward-looking design storms.
Screen crossings for fish and aquatic-species passage, flagging culverts that act as barriers to stream connectivity.
Recommend site-appropriate BMPs to reduce sediment, erosion, and flood risk at vulnerable crossings.
Under the hood
Each crossing’s contributing watershed is delineated from a digital elevation model, then scored with an integrated stack of peer-reviewed hydrologic and geomorphic models. Results land on an interactive map — toggle the DEM, watersheds, stream network, roads and road-stream crossings, and click any culvert for its full, method-by-method breakdown.
Validated at the Santee Experimental Forest (South Carolina lowlands) and Hubbard Brook Experimental Forest (New Hampshire uplands).
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In the news
How the CULVERT tool helps land managers and engineers pinpoint at-risk road-stream crossings before floods and storms strike.
Read the article
Journal of Hydrology, 2023
Environmental Modelling & Software, 2025
Environmental Modelling & Software, 2022
Journal of Hydrologic Engineering, 2021
Stochastic Environmental Research and Risk Assessment, 2023
American Meteorological Society, 2021
Who’s behind it