Darian
03-20-2015, 10:06 AM
Having nothing special to do this AM, I was thinking about the process of dumping large amounts of gravel in to rivers to create/improve spawning areas. This process seems to create problems, requiring the gravel be mined from another area, usually near a river/stream bed. Transporting the gravel and then dumping/spreading the gravel in-stream using heavy equipment. All of which appears to cost a bunch and damages riparian habitat and possibly requiring construction of new channels to accommodate the new gravel.
One of the threads in this Forum was about Gold Dredgers winning a suit setting aside a temporary order blocking their use on CA rivers/streams. That brought to mind a dredging machine developed in the late 60's for the US Forest Service called a riffle sifter. If you haven't heard of it before, the intent of this dredge was to "clean" riffles to enhance Salmon spawning areas/success. Unfortunately, these dredges were easily broken during operation resulting in lengthy down time. Worse, they required extensive maintenance that proved to make the dredges too costly to operate. Check out the link for an example of use on the Trinity River in 1971. Some of the photo's are poor quality but the report is interesting reading:
http://odp.trrp.net/FileDatabase/Documents/Use%20of%20the%20riffle%20sifter%20on%20the%20TR%2 019711.pdf
Probably wishful thinking but I wonder if it might be time to reconsider a newer, improved version of the riffle sifter for cleaning/improving in-stream habitat. Gold dredge sleds operate easily in-stream with only one or two people required to operate without extensive down time. Could a sled be modified/re-purposed to meet this need?? Operations could be done by fisheries professionals and might be carried out during the "off season" to avoid conflicts with spawning activities.
One of the threads in this Forum was about Gold Dredgers winning a suit setting aside a temporary order blocking their use on CA rivers/streams. That brought to mind a dredging machine developed in the late 60's for the US Forest Service called a riffle sifter. If you haven't heard of it before, the intent of this dredge was to "clean" riffles to enhance Salmon spawning areas/success. Unfortunately, these dredges were easily broken during operation resulting in lengthy down time. Worse, they required extensive maintenance that proved to make the dredges too costly to operate. Check out the link for an example of use on the Trinity River in 1971. Some of the photo's are poor quality but the report is interesting reading:
http://odp.trrp.net/FileDatabase/Documents/Use%20of%20the%20riffle%20sifter%20on%20the%20TR%2 019711.pdf
Probably wishful thinking but I wonder if it might be time to reconsider a newer, improved version of the riffle sifter for cleaning/improving in-stream habitat. Gold dredge sleds operate easily in-stream with only one or two people required to operate without extensive down time. Could a sled be modified/re-purposed to meet this need?? Operations could be done by fisheries professionals and might be carried out during the "off season" to avoid conflicts with spawning activities.