With nearly 2,000 miles of drivable road,
Prince of Wales Island is the most roaded area of all of Southeast
Alaska. Providing for fish passage at stream crossings is an important consideration
when constructing or maintaining roads, and a Tongass Forest
Plan priority.
Improperly located, installed, or maintained stream crossing structures, especially culverts can restrict upstream fish movement, thereby adversely affecting fish populations.
The most common obstacles include vertical barriers at culvert
outlets, debris blockages in culverts, and excessive water velocities caused by increasing stream gradient or constricting the stream channel through installing
undersized culverts.
|
A perched culvert on a fish stream which is blocking upstream fish movement.
|
Cutthroat trout captured in resident fish stream during Upstream Assessment survey.
|
Fish biologists and road engineers work closely together
to assess and improve road conditions with special emphasis on
fish passage. Road Condition Surveys have been conducted to identify
stream crossings that impair fish passage.
On impaired stream crossings an Upstream Assessment is done to determine the extent and quality of fish habitat upstream of the stream crossing.
To date, about 550 stream crossings on Prince of Wales Island have been identified as not meeting fish passage standards. There are also another 100 stream crossings that need further investigation to determine whether they are meeting fish passage standards. |
The data gathered from both the Road Condition Surveys and Upstream Assessments is used to help prioritize stream crossings restoration work. In some cases it is both economically and environmentally better to remove the stream crossing structure completely and put a road into storage. We are working cooperatively with other staff groups and agencies to fix fish passage problems. |
Stream simulation culvert
|
