Temperatures rose rapidly over the weekend melting three feet of snow in our watershed. The result is a huge flood and the little stream (West Fork of the Moose Horn River) that flows through my property has gone from 16 feet wide to almost 1,600 feet wide. Water depths have increased from 3 feet to about 6 or 7 feet depending on where you measure. And the speed of the stream’s flow has also increased although I have no measurements for that other than sore muscles from trying to paddle upstream so as not become part of the flotsam.
The rising and spreading waters clean out the stream and refresh it. They also flatten out the grasses and sedges in the shrub carr/sedge meadow making them less prone to fire. And for me they make it easier to visit the western sections of my property as I can canoe within 100 feet of the uplands. When the stream is at normal levels the walk is 1,300 feet through willow thickets and sedge tussocks.
The flood waters are stirring up many small aquatic animals which can be collected in simple traps like minnow traps. It is encouraging to find larvae of damselflies and caddisflies in the traps as most species from these insect orders require oxygen-rich waters to survive. Their presence and abundance indicates a good level of stream health. But not everything in my traps is an indicator of oxygen-rich water. Mudminnows (Umbra limi), Brook Sticklebacks (Culaea inconstans), and isopods (most seem to be Caecidotea) are tolerant of oxygen-poor water. When rainfall is abundant and regular the stream is full and the water fresh. But if rainfall is scarce or sporadic the stream’s water levels drop and the flow slows down. During drought years the stream will nearly dry up. This can be especially problematic in the winter when what little water there is freezes solidly to the stream bed. These conditions put a lot of stress on aquatic life and species that can tolerate that stress have a better chance of surviving. In recent years rainfall has been more consistent. The arrival of beavers, which had been gone for two decades, is also helping to keep water levels higher and creating new aquatic habitats where other animals and plants can live.
While the water is high many migratory waterfowl have arrived. Trumpeter Swans (Cygnus buccinator) and Hooded Mergansers (Lophodytes cucullatus) are two species that arrived this week. They will rest here for a short while and continue northward to their preferred nesting habitats. A pair of Canada Geese (Branta canadensis) and Sandhill Cranes (Antigone canadensis) have come back as have several pairs of Mallard Ducks (Anas platyrhynchos). These birds will stay here all summer tending their young. Redwing Blackbirds are back, too, fussing at intruders into their territory like me. Other songbirds, mainly warblers and sparrows, will being showing up soon to build nests in the willows and sedge. The flood will continue for several more days and eventually the shrub carr/sedge meadow will drain a little. Then the willows, grasses and sedges will start leafing out transforming the scene from one of bare twigs and brown thatch to green dotted with patches of aster and goldenrod flowers.