Mussels have been on my mind lately. Those of you who’ve seen me walking around in a sling this week know why. But yesterday it was mussels of a different sort that I was thinking about.
A big component of the restoration design is the installation of three riffles. These riffles are critical to the restored channel in several ways. Most importantly they control the grade of the river as it slopes through the site. By controlling the grade these riffles ensure that there is adequate water depth for fish to pass even at the lowest typical flows. They can be thought of as 3 big ‘steps’ that raise the water through this relatively steep section of the Jones. In this picture you can see the furthest upstream riffle immediately following its construction yesterday (9/29). The carefully selected and placed stone will ensure that sufficient upstream water depths are maintained and that fish can swim up the channel.
These riffles are a centerpiece of the design and when the project is complete the will contribute to improved habitat for a wide range of aquatic wildlife. Of course, construction is a disruptive business. The last thing we want to do is negatively impact wildlife while we are working to protect it. So early yesterday, as the water levels were adjusted to allow for the riffle install, we went on mussel patrol. Mussels can move surprisingly fast for a bivalve but sometimes they just can’t keep up. We walked the site where the water had been drawn down and relocated any of the mussels that were ending up high and dry.
Turtle, snail, and fish patrols were part of the process too. And everything was safely relocated away from the construction activities. It’s been amazing to see how quickly some animals have been to take advantage of the improved channel.