For my job today I got to spend some time exploring a stretch of Sand Creek upstream from my place. I run by the downstream end of that part of the creek nearly every day now, but I've never gone more than a short distance upstream. The 80 acre parcel the creek flows through there is owned by the state, and managed by my office for brook trout habitat.
Brook trout are particular about habitat, even more so than rainbow or brown trout, which are not native here. They need cold clean water with a variety of habitat including deep pools and gravel substrate for spawning. They do well in the larger streams on the North Shore of Lake Superior, but I have also seen them in very small streams.
This stretch of Sand Creek was mostly narrow (10 feet wide) and shallow, with sand for substrate. Much of the stream was shaded by alders that hung so low we had to lift them up to pass through or crawl underneath. Alders have a way of doing that. The shade keeps the water from warming in the sun, but the branches limit all but the most determined angler.
The water was cool. Cold, even. In a deep pool I held my hands underwater and had it not been such a hot day, it would have been uncomfortable after a short time. I have been in a few small streams around the area lately, but none with water nearly as cold as this. The source of much of the water became apparent as I moved upstream; here and there along the banks were flowing springs. I lost count of how many there were. Very unusual for streams in this part of the state! My theory is that this part of Sand Creek lies close to an ancient bedrock fault, and the bedrock is close enough to the surface to keep a layer of cold groundwater just under the soil's surface. The water table has been pretty low around here lately with the drought; I think in a more normal year those springs would have been flowing even more.
We were successful in sampling brook trout: three small adults and one young-of-year. We also sampled one mottled sculpin, which is a good indicator species for trout streams. I'll bet there were some more trout and sculpin in the deep pools we could not sample well. All were released unharmed.
Tomorrow I may be on Sand Creek again, a bit closer to home. I'll try to have the kids bring the camera out if we sample there!