I am afraid your photo does not show enough detail for me identify these insects with any certainty. However, given the time of year, they might be flies in the family Trichoceridae, the Winter Crane Fly family. Another possibility given the location and the unusually warm weather we have been experiencing in Michigan this January, is that they could be midges in the family Chironomidae (non-biting midges). Chironomid midges live in the water as immatures and normally do not emerge as adult flies until spring or summer.