Tidal Stream Crossings
Assisting community officials in a strategic approach to tidal crossing infrastructure improvement and restoration.
A tidal stream crossing (tidal crossing) is a bridge or culvert that conveys tidal flow below a traveled way, such as a road, pedestrian path, or railroad. When properly designed and maintained, tidal crossings can balance the needs of people and the environment by providing a functional, reliable and safe transportation network that supports the continuous movement of people, goods, and services across coastal communities while allowing adequate tidal flow to maintain healthy tidal marshes.
Resilient Tidal Crossings New Hampshire
In 2018, the NHDES Coastal Program and its partners assessed all known tidal crossings in New Hampshire's 17 coastal communities in accordance with the New Hampshire Tidal Crossing Assessment Protocol. Tidal crossing assessment data were used to rank and prioritize sites based on structure condition, flood risk and ecosystem health.
The Resilient Tidal Crossings NH Project was designed to better enable community officials and road managers to enact the strategic repair/replacement of tidal crossing infrastructure and to identify high priority restoration and conservation opportunities at tidal crossing sites.
Results of the project are available in a variety of formats:
Related Content
Prioritization Scores, Data and Summary Sheets
Tidal crossing prioritization scores, site data and tidal crossing summary sheets can be viewed through the NH Coastal Viewer. The entire tidal crossing database can be downloaded from the New Hampshire Statewide Asset Database Exchange (SADES).
Tools for Tidal Restriction Avoidance and Removal Webinar
On June 11, 2020, the New Hampshire Resilient Tidal Crossings Project was featured as the keynote presentation in the EPA Watershed Academy Webinar entitled: "Tidal Restriction Avoidance and Removal Webinar."
View Tidal Restriction Webinar
Wetland Rules for Stream Crossings
On February 18, 2021, NHDES Wetlands Bureau convened a multi-day workshop on recently promulgated administrative rules, which included a presentation from NHDES Coastal Program on Tidal Crossing Rules (Tier 4).
Tidal Crossing Replacements Through Tier 4 Tidal Stream Crossing Rules
The New Hampshire Resilient Tidal Crossings Project document gives stakeholders (e.g., municipal employees and committees, consulting engineers, transportation managers, and habitat restoration practitioners) a simple overview of the NHDES permitting process for tidal crossing replacement as well as to provide case studies of recent proactive tidal crossing replacement projects in New Hampshire’s Coastal Zone.
Assessment and prioritization of tidal crossing infrastructure
The final report "Resilient Tidal Crossings- An Assessment and Prioritization to Address New Hampshire's Tidal Crossing Infrastructure for Coastal Resilience" and associated appendices are available for download. If you have problems accessing any of these files, please contact us and we will provide accommodations.