Jeff Mount: Restoration is dead. What I mean by that is, humans are so integrated within rivers now that you really can’t separate the human signal from the natural signal. We will never restore our rivers to what they were like.
Jeff Mount is director of the Center for Watershed Sciences at the University of California, Davis. He said that – in a world of nearly 7 billion people – river restoration is about creating healthy ecosystems that can sustain human demands.
Jeff Mount: What we’re really doing when we’re talking about restoration is we’re restoring attributes of rivers – that is, those things which are desirable about a river.
Dr. Mount said these desirable traits include providing clean water, irrigation for agriculture, wildlife habitat, and recreation for people. He said the approach of controlling rivers with dams and levees impedes the natural processes that keep rivers healthy.
Jeff Mount: We’re looking at the notion of reconnecting our rivers. What I mean by that is moving those levees back, allowing the rivers to connect to their floodplains, and taking out dams where appropriate. And that reconnection actually restores a healthy river.
Mount said that allowing a river to flood occasionally can reestablish the natural movement of sediment, fish, and other wildlife, and maintain ecosystem services for humans. He added that in California, where he works, the state is now removing structures to allow flooding only in rural, agricultural areas.
Mount’s view of how to manage rivers stems from three basic principles. The first is to give rivers more room.
Jeff Mount: We have done a lousy job of giving room to our rivers. We continue to push urban development right up to the edge against rivers. That has two consequences. One, it degrades the rivers and the things we expect from that river, and two, it puts a lot of people and property at risk. So giving rivers room is the first thing to do.
Mount’s second principle is to reconnect rivers. He said that California is taking down a series of dams on Battle Creek to allow salmon and steelhead to swim upstream. Reconnecting rivers will also allow rivers to reclaim their floodplains. The third principle is to restore variability to rivers.
Jeff Mount: The traditional approach for engineering for a river is to make them behave. Don’t let them move, and don’t let them vary in time. That’s what we’ve tried to do for a hundred years in California, with large dams and levees, is to basically make a homogeneous river, and make it behave the same all the time. We have paid the ecological cost for that. Now, what we’re doing is looking at restoring variability with time. All native biota have adapted to our variable climate, but yet our engineering approaches seek to engineer all that variability out of the system. Now we’re trying to bring that back.
Mount said that restoring rivers this way will create healthier soils, groundwater systems, and fisheries, and provide benefits to neighboring ecosystems as well.