By now I’m sure you are all fully familiar with the Bureau of Reclamation graph of local reservoirs and rivers used to irrigate the high desert. In non-drought years the reservoirs are full early in the irrigation season, but only Crane Prairie and Haystack are near that level today. Haystack is an intermediate reservoir used by North Unit Irrigation District to temporarily hold water from Wickiup and Crane Prairie is kept full early in the season for Oregon Spotted Frog habitat as required by the Deschutes Basin Habitat Conservation Plan. What is less well known is the dramatic change in river levels caused by irrigation diversions, a change which is lethal to many forms of aquatic life.
If you go to the BoR website and click on the various red dots you will be taken to river flow graphs covering the past week and can then follow another link to the full year graph. The flows coming into Bend, for example, have recently and abruptly more than doubled. Of course, this scours the river channel, releasing sediment that clogs spawning beds and buries aquatic animals and plants.
More concerning is the Deschutes River below Bend after the final irrigation withdrawal at North Canal Dam near Rivers Edge Golf Course. In just a few days earlier this month, the river dropped from 394 cfs to 64 cfs. (CFS = cubic feet per second.) In only a few hours yesterday it shot up from 64 cfs to 258 cfs and is currently dropping back almost as quickly. These extreme flow changes wreak havoc on all forms of aquatic life.
The most extreme damage is occurring on the Crooked River. Anglers typically welcome the increased flows in the Wild & Scenic section below Bowman Dam which are now at 143 cfs after being 50 cfs for most of the winter, but after a series of downstream irrigation diversions, today the flows in the river below the City of Prineville are at 2 cfs! Think about a river with only 15 gallons of water in it as it passes by. Talk about killing a river! It won’t be long before spring chinook salmon start arriving. Last year, the Crooked went dry in sections when salmon were attempting to move up the Crooked.
There’s a lot of talk about irrigation districts working to improve flows in the Upper Deschutes River (above Benham Falls). Improved flows are certainly welcome, moderating the extreme fluctuations over longer periods would be even better. Unfortunately, there are no plans to improve conditions in the Middle Deschutes or the Crooked River. Today, they are in far worse shape than the Upper Deschutes.