The creek/flood control channels in Cotati for years have been cleared of most trees and shrubs. How will the plantings affect flood control?
For decades creeks and flood control channels were typically stripped of all trees and shrubs that were thought to interfere with flood conveyance and channel maintenance. This creates several problems that have been recognized and this has caused a major shift in maintenance practices, not just here, but throughout California. 1) With an abundance of water, fine sediments and full sun, the creek channel becomes ideal for vigorous plant growth. Channels become overgrown with fast-growing vegetation including invasive non-native Himalaya blackberry. Native cattails and other emergent plants also thrive in these conditions. This in-channel vegetation can reach 8’ in height in a single season and is difficult to manage. This growth traps more sediment and trash, filling in the channel and lowering flood capacity. 2) Water in the channel exposed to the sun heats up. Warm water contains more bacteria and less dissolved oxygen than cool water. Native aquatic life, including steelhead and sal
