The post on the shrinking Willamette River system was unhappy. At the end of that post I mentioned that restoring the ecological functions of the river involved working with modern land use and human structures in the landscape. Here is how that might happen. This week in our Master Naturalist class, we visited a farm that is a step in the right direction.
Look at this current view of a section of the Willamette River:
If you zoom in you can see labels for lakes along the right (east) side and over to the left of center. These lakes are hydrologically connected to the main river. Here is the diagrammatic view of the river at the time of European settlement and as sloughs and side channels were drained for agriculture from the mid-1800’s till now :
Aerial views give a different perspective on the adjacent wetlands and their importance to a river. Those lakes in the color map are side channels and oxbow lakes that were part of the river at one time. During high flows and floods, juvenile fish (like the endangered Chinook salmon) will find refuge in side channels; there they grow larger and hide from predators. When the water level recedes, they move downstream, better able to survive the rigors of life in the main channel as they head out to sea. That’s just one of the many functions of channels and sloughs in adjacent wetlands. And one species. Another ecosystem service provided by these wide flat spots is to dissipate the force of stormwater coming down the channel and spread out the volume of water during high flows.
In this farmer’s field there are several native species of fish that hang out in the winter when the water rises (yes-IN the field! remember this was once the river). He has built water control structures to facilitate their movement in and out, so they don’t get trapped in the side channel when it dries out. He has planted trees and hedgerows along the river for habitat. These plants also provide a buffer to absorb fertilizer and insecticides, and protect the river bank and crops.
Here is a closer aerial view of the sloughs (the dark green shrubby areas between fields) and banks planted with trees. You can also see another feature that all farmers should have right in the field – hedgerows of native plants. They look like thin dark stripes in the field in the lower left part of the aerial map.
This view on the ground is dramatically set against the big storm that was on the way this weekend to dump about 2.5 inches of rain on us. The hedgerows are mostly hardhack (Spiraea douglasii) and the one in front is overrun with blackberries. Both provide a lot of value as insect rearing habitat. However, a mix of species provides multiple generations of beneficial insects nectar, food, and places to pupate. That saves on pesticides.
What do you think? If every farmer or landowner with property near a waterway was to enhance one ecosystem service their patch provides, instead of thinking only of protecting crops, houses, or buildings, could we integrate enough habitat and resilience back into the Willamette River system to bring it back to health? Would residents downstream perhaps be willing to provide assistance to upstream residents to help prevent flooding in the streets of Portland?
One last note: buy Flav-R-Pac and Santiam brands – it’s a local farmer’s cooperative that this farm belongs to, and it keeps farmland out of development. If you buy organic – look for the Ladybug logo on produce – this farmer’s neighbor grows organic produce for them. That’s a whole nother story.