estuary

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By this time each spring, the Rogue River estuary tends to have taken its shape for the rest of the year. Most of the major weather events shaping the river typically happen in winter, with rare exceptions. In April 2019, there was a momentary threat of flooding with a rain-on-snow event, in which heavy rains and a warm front led to rapid snowmelt in the river’s upper reaches. 

For people living in Gold Beach, the estuary morphing happens so slowly that year-over-year changes tend to go unnoticed. But many residents do notice changes from their memories of the river 10 or 20 years earlier. They’ll recall bends, shoals, backwaters, deep runs and secret spots that have moved or appear missing. 

And while individuals may have memories of their ideal river conditions, there isn’t a baseline year when one can state that river contours were exactly as they should be. That’s because the river changes constantly, on its own. 

A comparison of three aerial views of the estuary, taken at roughly 40-year intervals, shows huge changes in river contours. None of the images represents the ideal state; the combination shows a river in constant flux. 

The image from 1939 shows two viable channels, two main islands and two additional spits that likely became islands in high water. Forty-one years later, in 1980, the image shows consolidation into one channel with a sharp bend on the river’s south side. In 2019, 39 years on, the major curve is gone and the river now has more backwater habitat, with large sloughs on either side of the channel. 

Estuaries provide juvenile salmon with shelter, food and a mix of sea and freshwater that allows for a gradual transition from rivers to the ocean. For many salmonids, adding weight and size before entering the ocean improves their chances of survival and a return to spawn.  

“One thing we can say is that the Rogue River wild salmon and steelhead runs are doing pretty good compared to rivers elsewhere in the state,” said Steve Mazur, District Fisheries Biologist with the Oregon Department of Fish and Wildlife. “As with any population there are average years and there are great years, but in a comparative sense, these stocks are in much better shape. They are more resilient because the in-river habitat is good and getting better. That has to do with managing river flows out of the Rogue’s two big reservoirs, dam removal upstream, habitat improvements on tributaries, and an increasingly healthy, dynamic estuary. Here in the estuary, juvenile fish can find the necessary food and shelter.” 

This matters because salmon are vital to both the local economy and the local culture. 

The current river likely has more gravel than was visible in the previous decade, a shift that may be attributable to the removal, beginning in 2009, of four large dams in the upper Rogue basin. But, like everything else with the river, that shift is temporary. 

“If the goal is a healthy salmon population, gravel bars and large wood are a positive thing,” said Kelly Timchak, Coordinator, Lower Rogue Watershed Council (LRWC). “They offer shallow water and cover, to help juveniles avoid larger predators. The increased surface area along the bottom allows for more abundant insect life – a key source of protein for fish putting on weight before heading out to sea.” 

• Kevin Sweeney is an environmental writer and consultant.

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