Road Stream Crossing Assessments

Culverts are a major inhibitor for aquatic passage, they also alter habitats and disrupt river and stream continuity. Most of the culverts in Franklin County were designed with the principal objective of moving water across a road. Little consideration was given to ecosystem processes such as the natural hydrology, sediment transport, aquatic organism passage, aquatic habitat or the movement of woody debris. Many of the culverts significantly disrupt the movement of aquatic organisms, are failing and causing additional sediment loading into the watercourses due to being undersized. These road-stream crossings are causing fragmentation of critical habitat for various aquatic species.


 The movement of organisms within rivers and streams is an important ecological process that can be significantly affected by road crossings. There are several ways that crossing structures can impede or prevent the movement of animals: inlet or outlet drop, physical barriers, insufficient water depth, absence of bank edge, discontinuity of channel substrate, etc. Unless properly designed and constructed, road stream crossings can hinder or obstruct the upstream movement of fish and other aquatic and riparian-dependent organisms. Re-establishing aquatic organism passage is a key component of restoring ecological conditions by connecting fragmented habitats. Passage is often a first step in restoring watershed condition, which benefits fish and other aquatic and riparian species. Healthy and ecologically viable ecosystems are dependent on the long-term conservation of important aquatic resources. The ecological integrity of river and stream systems have the potential to be undermined by road stream crossings. The productivity and viability of river and stream ecosystems is dependent upon the quality of the physical environment, maintaining intact communities of aquatic organisms, and to ensure not to disrupt critical ecological processes.

 Over the past 3 years Franklin County Soil & Water staff have been working throughout the county to conduct road stream crossing assessments utilizing the North Atlantic Aquatic Connectivity Collaborative (NAACC) Protocol. These projects identify the areas throughout the county that are having an impact on the aquatic organism habitat and passage. Road stream crossing assessments are conducted to help identify bridges and culverts that are problematic from an aquatic connectivity, aquatic habitat and stream bank stability perspective.

In 2019, staff focused on the Chateaugay-English Watershed. This watershed covers portions of six municipalities including the towns of Bellmont, Burke, Chateaugay, Constable, Malone and Westville. This assessment identified the structures that are undersized and are constricting the watercourses causing interconnectedness within and among the system and also for the protection of ecosystem structure, function and key processes. Information was collected on 328 road stream crossing structures. The information collected was compiled in a report and distributed to the municipalities involved. The district is now working with these municipalities to prioritize projects based on this information and obtain grants to replace the highest priority structures.

This document was supported by agreement with New York Sea Grant, funds provided by the Environmental Protection Fund under the authority of the New York Ocean and Great Lakes Ecosystem Conservation Act. Any opinions, findings and conclusions or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of Stony Brook University or New York Sea Grant.