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Pre-field risk assessment of Road-Stream Crossings

CULVERT Web Application

Climate and Upland Loading Vulnerability Evaluation and Risk Analysis Tool (CULVERT)- screening road-stream crossings for floods, soil erosion, and post-wildfire debris flow.

Find at-risk culverts before they fail Automated hydro-geospatial screening across the continental U.S.
Flooding & overtopping Flag crossings where peak storm flows exceed the culvert’s capacity.
Upland soil erosion WEPP & RUSLE sediment that aggrades and plugs the culvert inlet.
Debris flow Saturated sediment and woody debris that surge down and choke the crossing.
Stream-bank erosion Channel widening that undermines the culvert and its road embankment.
Project Information Static Dashboard

Why CULVERT

Find at-risk culverts before they fail

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.

Diagram of the CULVERT analysis workflow
The end-to-end CULVERT workflow

Assessed today

Flooding & overtopping

Peak storm flows exceed the culvert’s hydraulic capacity.

Upland soil erosion

WEPP & RUSLE sediment that aggrades and plugs the inlet.

Debris flow

Sediment and woody debris surge down and choke the crossing.

Stream-bank erosion

Channel widening undermines the culvert and road embankment.

On the roadmap

  • Landslide
  • Post-fire landslide
  • Post-fire erosion
  • Post-fire debris flow
  • Future CMIP6 climate projections
  • Aquatic organism passage
  • Best management practices

Nationwide, ready to run

Required datasets are integrated through open, reliable data APIs across the continental U.S.

No culvert data? No problem

If you don’t have crossing locations, the tool automatically generates candidate culvert sites and assesses them.

Hyperlocal risk assessment

Assess risk at spatial resolutions up to 1 m or submeter scale, with temporal resolution down to 1 hour.

Decide before the field visit

A pre-field risk assessment that prioritizes limited maintenance budgets and informs climate-resilient sizing - on all lands, not just federal property.

One tool, three vantage points

GIS analysts & field engineers

Get to the right crossing, faster

Delineate watersheds, pull design rainfall, and export ready-to-use shapefiles and reports - so field visits target the culverts that actually need eyes on them.

Land managers & policy makers

Spend limited budgets where they count

A clear, ranked picture of at-risk crossings across all lands - to prioritize inspections, justify funding, and plan climate-resilient redesigns with confidence.

Researchers & scientists

Reproducible, transparent, extensible

Peer-reviewed methods - regional frequency analysis, TR-55/TR-20, RUSLE, WEPP, SBEVA, WDFM - with downloadable inputs and outputs for reproducible research.

Collaborators & funding

  • U.S. Department of Transportation Major funding
  • USDA Forest Service
  • University of North Georgia
  • University of Idaho

Ready to assess your culverts?

Create a free account or sign in to delineate watersheds and run a vulnerability assessment for your road-stream crossings.

How it works

Three modules, one story

CULVERT turns a bare digital elevation model into a culvert-by-culvert pre-field risk assessment in three guided steps. Scroll to watch each module come to life - delineate the watershed, score the flood risk, then score the sediment and debris risk.

Delineating contributing watershed…
Module 01

Watershed Delineation

Point CULVERT at a road-stream crossing and it pulls a USGS DEM, conditions it, and carves out the exact watershed draining to that culvert - plus the stream network and pour point. Bring your own crossings, or let the tool generate candidate sites automatically.

  • Auto-fetched 10 m / 30 m USGS elevation
  • Nested & multi-outlet delineation
  • Stream network and snapped pour points
Sizing the design storm against capacity…
Module 02

Hydrologic Vulnerability

CULVERT pulls NOAA Atlas 14 design rainfall, runs regional frequency analysis and TR-55 / TR-20 / Rational methods to estimate peak discharge with confidence bands, then checks it against the crossing’s hydraulic capacity - flagging culverts that overtop or wash out.

  • Non-stationary, climate-aware design storms
  • Peak flow with lower / expected / upper bands
  • Headwater-to-diameter capacity check
Scoring sediment, erosion & debris risk…
Module 03

Hydrogeomorphic Vulnerability

The geomorphic stack - SBEVA bank erosion, RUSLE and WEPP cloud soil loss, and the WDFM debris-flow model - rates how much sediment and debris each watershed can deliver, then fuses them into one EHVI ensemble score per crossing so you can rank where the real risk is.

  • Bank erosion, upland soil loss & debris flow
  • Process-based WEPP cloud erosion modeling
  • One defensible EHVI ranking per culvert

Under the hood

The science inside CULVERT

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.

Non-stationary regional frequency analysisDesign storms under a changing climate, with scenario assessments
SCS TR55 and TR20 & Rational MethodPeak discharge with confidence bands
Culvert hydraulic capacityCan the crossing pass the design peak flow?
SBEVAStream-Bank-Erosion Vulnerability Assessment
RUSLERevised Universal Soil Loss Equation for upland erosion
WDFMWatershed Debris-Flow Model
WEPPWatershed Erosion Prediction Project (cloud)
EHVI - ensemble vulnerability indexCombines SBEVA, RUSLE, WDFM & WEPP into one rating

Validated at the Santee Experimental Forest (South Carolina lowlands) and Hubbard Brook Experimental Forest (New Hampshire uplands).

Published Research

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A watershed-scale multi-approach assessment of design flood discharge estimates used in hydrologic risk analyses for forest road stream crossings and culverts

Journal of Hydrology, 2023

Mukherjee et al., 2024

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Hydro-geomorphological assessment of culvert vulnerability to flood-induced soil erosion using an ensemble modeling approach

Environmental Modelling & Software, 2025

Mukherjee et al., 2025

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Extreme precipitation-based vulnerability assessment of road-crossing drainage structures in forested watersheds using an integrated environmental modeling approach

Environmental Modelling & Software, 2022

Panda et al., 2022

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Estimates of Precipitation IDF Curves and Design Discharges for Road-Crossing Drainage Structures: Case Study in Four Small Forested Watersheds in the Southeastern US

Journal of Hydrologic Engineering, 2021

Amatya et al., 2021

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Comparison of on-site versus NOAA’s extreme precipitation intensity-duration-frequency estimates for six forest headwater catchments across the continental United States

Stochastic Environmental Research and Risk Assessment, 2023

Mukherjee et al., 2023

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A Proposal for a New, Simplified Methodology for Design Flow Modeling in Ungauged Catchments

American Meteorological Society, 2021

Młyński et al., 2025

In the news

News & media