Oh, it’s a wild ride of river fluctuations again on the Huron at the Wall Street Stream Gauge, just downstream of Argo Dam.
Looking at the USGS stream gauge at Wall Street in Ann Arbor in the last 16 days shows dramatic swings in river flows. This hydrograph shows erratic river flow, as indicated by the steep peaks and valleys, and is typical of the gauge data recorded at this site regardless of weather and precipitation. See the graph below and notice 6 different spikes in water levels including 2 spikes below 100 cubic feet per second (cfs) and 1 spike down to under 70 cfs — pretty much zero flow over the dam. Within a few minutes the river then rapidly rises to close to 1,000 cfs. Imagine what it would be like to be a fish or to be fishing when this unnatural event occurs!
We are looking into the causes of these fluctuations, but they’re disturbingly common at the Wall Street Gauge. Argo dam is just upstream of this gauge, and the Huron River at Argo Dam has one of the top two most erratic flow regimes in Michigan, according to the USGS. These irregular releases destroy natural seasonal flow variations that trigger natural growth and reproduction cycles in many species. Paul Seelbach, MDNRE and University of Michigan fisheries biologist, has stated that flow fluctuation is the “Number 1 variable in the river that we care about” as an indicator for fisheries health. As a local angler puts it, “Small mouth bass spawning season is just beginning right now. Many of my fishing buddies are already observing fish on their beds. Fluctuations like this can expose spawning beds to the air (killing eggs) when water spikes too low, and wash away eggs and fry when water spikes too high.”
Two other USGS gauges upstream — one on the river in Hamburg, and one on Mill Creek at Parker Road (near the Village of Dexter) — show none of these rapid swings. Over a similar time period they show healthy, natural river flow with only 100 cfs variations over the same time period shown for Ann Arbor!
This is a critical time for these dramatic low flows and wild fluctuations. These swings will kill a lot of critters; fish only one of them. The river saw a half-dozen of these wild swings last year and HRWC is very concerned about the frequency. HRWC is working with City staff and regulators to try to fix this problem. However, the inability to moderate downstream flows is a major reason we, the Michigan DNRE and others call for Argo Dam removal.