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Development of a Rapid Assessment Protocol for Aquatic Passability of Tidally Influenced Road-Stream Crossings

Tidally Influenced Crossings

There is growing interest among conservation practitioners to have a method to assess tidally influenced crossings for their potential as barriers to aquatic organism passage. Protocols designed for freshwater streams will not adequately address the passage challenges of bi-directional flow and widely variable depth and velocity of tidally influenced systems. Diadromous and coastal fish must be able to overcome the enhanced water velocities associated with tidal restrictions to reach upstream spawning habitat. This project will build on the existing North Atlantic Aquatic Connectivity Collaborative's protocol, database and scoring procedures to extend the applicability of this region-wide program to road-stream crossings in tidally influenced settings.

With support from the North Atlantic LCC and Hurricane Sandy Disaster Mitigation funds the North Atlantic Aquatic Connectivity Collaborative (www.streamcontinuity.org) has developed a regional crossing assessment protocol and database, scoring systems for aquatic organism passage, and hydraulic risk of failure assessments based on future storm discharge levels. The existing NAACC protocol was developed primarily for freshwater streams and the suite of organisms that occur in these systems. There is strong interest among conservation practitioners to have a method to assess tidally influenced crossings for their potential as barriers to aquatic organism passage. Protocols designed for freshwater streams will not adequately address the passage challenges of bi-directional flow and widely variable depth and velocity of tidally influenced systems. Diadromous fish and other organisms must be able to overcome the enhanced water velocities associated with tidal restrictions to reach upstream spawning habitat. This project will build on the existing North Atlantic Aquatic Connectivity Collaborative's protocol, database and scoring procedures to extend the applicability of this region-wide program to road-stream crossings in tidally influenced settings.

A workshop for those in the Northeast US and Canada that are interested in tidally influenced crossings was organized by the Northeast Regional Ocean Council, the Gulf of Maine Council, and the North Atlantic Landscape Conservation Cooperative. It was held on September 10 2015 in Portsmouth, NH and representatives from two Canadian provinces and six northeast states attended. The agenda and the attendee list are available. Each jurisdiction was asked to prepare a short presentation descibing their management concerns on this topic, and the status (if any) of field or desktop assessments of tidally influenced crossings.  Links to the presentations from Nova Scotia, New Brunswick, Maine, New Hampshire, Massachusetts, Rhode Island, Connecticut, and New York are available.  Washington state has a lot of experience in this area especially as salmonids are concerned. Two representatives presented at the workshop to inform us of their process and work done to date. Notes and action items from the workshop are available here.

In February, 2016 an agreement was completed with the University of Massachusetts, Amherst to develop a tidal crossing module to the existing North Atlantic Aquatic Connectivity Collaborative protocol. Notes from a preliminary call of project partners are here.

The North Atlantic LCC is supporting cooperators from the University of Massachusetts, Amherst to conduct literature reviews and develop a draft tidally influenced crossings survey protocol as part of the larger North Atlantic Aquatic Connectivity Collaborative (www.streamcontinuity.org).

The region of interest spans the entire North Atlantic LCC geography.

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