Oscoda sits at the mouth of the AuSable River on the Lake Huron Sunrise Coast, and for me it is the most personal page on this site. I am Chris Izworski. I fish the AuSable several times a year, particularly the Holy Waters between Mio and McMasters Bridge, and I treat the river and its mouth as part of my home water. The AuSable is the river that taught me how lake levels and river hydrology interact at a working trout angler's scale. This page is the practical orientation for Oscoda property owners, anglers, and visitors trying to understand the relationship between Lake Huron levels and the river they care about.
The AuSable is approximately 138 miles long, draining roughly 1,924 square miles of north-central Lower Michigan from headwaters near Frederic to the mouth at Oscoda. Below Mio the river is impounded at six hydroelectric dams operated by Consumers Energy. Foote Dam, the most downstream impoundment, sits about ten miles upstream of Oscoda. The water leaving Foote Dam is the water arriving at Oscoda, modulated only by the small Pine River and a few minor tributaries below the dam. The tailwater section between Foote Dam and the mouth is where the lake-level question really lives.
The lower three miles of the AuSable, from US-23 downstream to the harbor mouth, is essentially a backwater of Lake Huron. River surface elevation in that reach tracks Lake Huron stage almost exactly. When Lake Huron is two feet above mean, the river through Oscoda is two feet above its long-term mean elevation, and the floodplain behind the US-23 bridge takes on water that property owners would prefer it not take on. When Lake Huron is two feet below mean, the river through Oscoda is two feet lower, the sand bar at the harbor mouth grows, and the navigation channel narrows.
The Oscoda harbor itself is a federally maintained channel that periodically requires dredging at the bar. The 2012 to 2013 low water cycle produced acute operational difficulty at the harbor mouth and required emergency dredging consultation with the Detroit District. The 2019 to 2020 high water cycle produced the opposite problem of flooded river-mouth properties and pier wave action along the South Channel.
Foote Pond, the impoundment behind Foote Dam, operates as a hydroelectric reservoir under FERC license. Consumers Energy modulates flow within the license terms, which means the AuSable through Oscoda is not a wild discharge but a managed one. That has practical implications. River level at the US-23 bridge is set by lake stage at the downstream end and by Foote Dam release at the upstream end. In low lake years and low dam release periods, both sides of the system pull the river down. In high lake years and high dam release periods, both sides push the river up. The worst flood events at Oscoda are the rare cases where high lake stage and high Foote release coincide.
The Holy Waters, the catch-and-release fly fishing reach between Burton's Landing and Wakeley Bridge upstream of Mio, are about sixty miles upstream of Oscoda and are not directly affected by Lake Huron stage. They are mentioned here because the Holy Waters draw the angling economy that sustains the lower river fly shops, lodges, and guide services at Oscoda, Mio, Roscommon, and Grayling. A healthy AuSable mouth at Oscoda matters to that broader economy even when the mouth and the Holy Waters are hydrologically disconnected.
For lake stage at Oscoda, the relevant NOAA gauge is the Alpena station 9075099 to the north or the Harbor Beach station 9075014 to the south. For river stage and discharge, the relevant USGS gauges are AuSable River near Mio (04135700) and AuSable River near Oscoda (04136500). The Oscoda USGS gauge captures both the regulated discharge from Foote Dam and the lake-level backwater effect at the lower reach. Reading both gauges in combination is the right practice for any Oscoda property owner trying to anticipate river-mouth conditions.
Property owners along the lower AuSable and along the Lake Huron shoreline north and south of the river mouth should plan against the same envelope I describe for the broader Sunrise Coast. Design seawalls and docks against the 1986 high water mark plus a foot, plan for storm surge of up to two feet from northeast events, and account for the additional river stage variability if the property is on the river itself. River-mouth properties have a more complex risk profile than pure lakeshore properties because both forcings operate.
I cover the wider Lake Huron picture on the Lake Huron overview and the Sunrise Coast on the Sunrise Side page. Questions about Oscoda can come to Chris Izworski at chrisizworski.com.