Fish Passage and Connectivity in the Ausable Watershed using GIS Prioritization and Field Assessment Tools Report Released

Recent evidence suggests that fish passage at the sub-watershed level may be impaired in the Champlain
Basin (Bates and Kim 2007). Road culverts, bridge structures, small dams and other human engineered
infrastructure often place demands on small fishes that may exceed swimming burst speed and/or leaping
abilities (Clarkin et al. 2005). Often road crossing structures have interfered with hydrological processes that normally serve to maintain upstream-downstream connections and could threaten local fish
populations with extinction (Letcher et al. 2007). The Eastern Brook Trout Joint Venture lists stream
fragmentation from road culverts as one of the top ten threats to wild brook trout across 17 states. Within New York, roads, dams, and culverts are identified as threats to biodiversity in up to 15 conservation action plans, including the Adirondack Mountains and Lake Champlain (ConPro. 2007). Accumulating evidence points to the need and opportunity to remedy these problems as culverts and bridges fail or are replaced during road upgrades.

This need for attention to road crossing infrastructure is magnified with consideration of climate change
predictions for the Lake Champlain Basin. A recent The Nature Conservancy report, entitled Climate
Change in the Champlain Basin: what natural resource managers can expect and do (Stager and Thill 2010) used Climate Wizard (a GIS planning tool) to downscale global circulation models in order to predict potential climate change impacts to the basin. Models anticipate more frequent severe storm events, a 15% increase in annual precipitation, and mean lake levels rising by up to two feet by the end of this century. This suggests record floods which occurred in 2011 could be ‘the new norm’ in the future. Already, climate records show that mean annual temperature in the North Country has warmed 1.5 degrees C and weather records from stations within the North Country region show an increase in large, high intensity rainstorms (Jenkins 2010).

One strategy identified as an important response to the potential impacts on streams from climate change
involves removing barriers to aquatic species movement, so that native trout and other aquatic organisms
in main-stem rivers can move unencumbered into colder tributaries as summer heat waves increase in
frequency. Furthermore, the larger culverts and bridges that allow fish movement are also more likely to
withstand more frequent flooding. Healthy tributary segments allow for wildlife adaptation and therefore
the conservation of fish populations as well as improved resilience of human communities in the face of a
changing climate.

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