Stream Flow Turbidity Monitoring during Construction

Any in-stream construction work requires permits from US Fish and Wildlife Service. The permitting is based on assumptions of turbidity extent and intensity, which impacts fish health and survival. The permitting restricts us to in stream work so having better quality turbidity data should open work windows, since current assumptions are very likely conservative. This is based on our experience. Currently the study team assumes that turbidity could go 1000 feet downstream from cofferdam placement and other activities at levels that could cause harm to fish. There is not a good body of literature to understand and support these assumptions. If the study team can show that the effects are lesser in extent and severity, it will help us angle for more flexible in water work windows. Turbidity data collection supports the Maine Department of Transportation (MaineDOT) and the U.S. Fish and Wildlife Service programmatic agreement. Over the past two years, MaineDOT has hired Stantec to establish baseline data and determine future turbidity limits related to in-water construction events and their effects on Atlantic salmon (Salmo salar) and its critical habitat protected under the Endangered Species Act. This included turbidity data collection at two sites with in-water construction in 2020 and four project sites in 2021. The tasks in above mentioned work include establishing monitoring points prior to construction, collecting pre-construction (baseline) and syn-construction (during construction) turbidity samples, reviewing laboratory results, and providing a summary report for each project site. The water sample data collection will be performed as described in Appendix C and D of the “User’s Guide for the Maine Atlantic Salmon Programmatic Consultation (MAP) Version 1.0, March 2017”. The study team has developed turbidity monitoring protocols and recently hired Stantec to collect measurements. The study team has a protocol to follow to determine turbidity levels and there’s solid research on extent and severity that can cause harm to fish. However, turbidity is very specific to the location and stream bed composition among other things. More data collection at sites with in stream work is required and a comprehensive analysis of the data before impactful results (more flexible in stream work windows) can be determined.


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    • Status: Programmed
    • Funding: $75000
    • Sponsor Organizations:

      Maine Department of Transportation

      16 Statehouse Station
      Augusta, ME  United States  04333
    • Project Managers:

      Peabody, Dale

    • Start Date: 20220331
    • Expected Completion Date: 20240301
    • Actual Completion Date: 0

    Subject/Index Terms

    Filing Info

    • Accession Number: 01790319
    • Record Type: Research project
    • Source Agency: Maine Department of Transportation
    • Files: RIP, STATEDOT
    • Created Date: Dec 3 2021 12:42PM