Culvert Assessment Project


In 2016 Ulster County Department of the Environment began a project, partly funded by a grant from the New York State Environmental Protection Fund through the Hudson River Estuary Program of the New York State Department of Environmental Conservation, to assess the county road-stream crossings for general condition and aquatic passability using protocol developed by the North Atlantic Aquatic Connectivity Collaborative (NAACC).

The NAACC is a participatory network of practitioners united in their efforts to enhance aquatic connectivity. The NAACC project will support planning and decision making by providing tools and information on where restoration projects are likely to have the greatest aquatic connectivity benefits and resiliency benefits. All data collected is available for viewing and download at:


Culvert Field Assessments

 After reviewing assessment protocols, we received training from the DEC on the North Atlantic Aquatic Connectivity Collaborative (NAACC) protocol for road stream crossing assessment. This protocol focuses on the condition of the culvert and its suitability for the passage of aquatic organisms. We produced field maps and began our assessment of the county road-stream crossings in the summer of 2016. New field crews were hired and trained each year and assessments continued. The field assessments and data entry continued each season through the summer of 2018. In 2018, we included assessments for town roads in the Sawkill subwatershed in order to create a more complete network of mapped culverts for potential future hydrologic analysis. The Ulster County Department of the Environment assessed all culverts on county maintained roads throughout Ulster County, assessing a total of 434 culverts including the county road crossings (excluding roads in the Ashokan Basin NYC watershed which were were assessed by the Ashokan Watershed Stream Management program, AWSMP) and town road-stream crossings in the Sawkill basin. All data was entered into the NAACC database and reviewed.  Data is available for viewing and download on the NAACC search site:


Data Creation

Beyond the field assessment elements of this project, an important additional component has been spatial data creation to support more detailed hydrologic, hydraulic and spatial analysis. In 2015, Ulster County received a 1m LiDAR digital elevation model (DEM) data set from USGS for the entire county. We contracted with GroundPoint Technologies to process the available 1m DEM to produce  a hydro-enforced 1m digital elevation model (DEM) for Sawkill drainage which can be used for advanced hydrologic modeling. GroundPoint examined the culvert capacity model that Cornell Water Resources Institute developed and adapted it to calculate polygon drainage areas for culvert points in the Sawkill drainage basin using this enhanced DEM.


Subsequently in 2016, new high resolution land cover data was produced for the Delaware River Basin in conjunction with the University of Vermont ( Because part of Ulster County is in the Delaware River Basin, we were provided this enhanced land cover data for all of Ulster County, not just the portions within the Delaware basin. Using funds from this grant, we contracted with Green Infrastructure Center, Inc (GIC) to produce updated habitat cores mapping using this enhanced land cover data. Previously, in 2012, GIC had produced habitat mapping for Ulster County using older, coarser (10m NLCD) land cover data. The new higher resolution land cover data produced a significantly more detailed core habitat assessment data set. We then used the new habitat cores data to further analyze which culverts might serve as connections between these important high quality habitat cores. (Additional information on the Green Infrastructure Center and the New York manual featuring habitat mapping in Ulster County is available at ).


Interaction and Support to Municipalities and Other Groups

In August 2018, we met with the Town of Woodstock Highway Department to discuss assessment of culverts on town roads within the Sawkill Basin which encompasses a large part of the town. At the time of our meeting, staff at the Woodstock Highway department were just beginning to use GIS. After we conducted the field assessments, we produced a map  and spreadsheet on the culverts that we had assessed within the town. We met again in October 2018 to demonstrate how to download data and shapefiles from the NAACC website. We also created a map of the culverts assessed within the entire Sawkill basin.

In September 2018, we gave a public presentation in Woodstock sponsored by the Woodstock Land Conservancy and Woodstock Environmental Commission on the Ulster County Culvert Project. 

We have interacted with the Town of Esopus and Tighe & Bond Consulting Engineers on a project they are conducting in the Town of Esopus through a grant from the Hudson River Estuary Project to map and assess culverts in the town. This project will then advance a few culverts to a conceptual redesign and recommendations for replacement.


Additional Analysis and Next Steps

There are many aspects of this project that are ongoing. We will continue to engage with and support Ulster County municipalities, watershed, and environmental groups in culvert mapping, assessments, and modeling. Also, the data collected has been and will continue to be used by the Ulster County Department of Public Works, Highway Division in considering culvert replacement prioritization.

We are actively pursuing ways to complete a more detailed hydrologic and hydraulic analysis of the culvert data set and particularly the Sawkill subdrainage. In October 2018, we convened a meeting with representatives from NYSDEC HREP, Cornell WRI, GroundPoint Technologies, Ashokan Watershed Stream Management Program, and the Ulster County Department of the Environment for a preliminary discussion on next steps of using the Sawkill data for further hydrologic and hydraulic analysis.