Streaminders

Protect Rock Creek and Manage Flooding

by Roger Cole and Tom Leonardi

Existing Conditions

Rock Creek as it flows through Butte County exists in a variety of conditions. In some agricultural areas there are deep pools and riparian vegetation where both adult and juvenile salmon reside in the springtime, white-tailed kites nest in adjacent valley oaks and occasional bald eagles sit in a stream-side tree watching for an opportunity to pick up one of the thousands of spawning suckers in the creek. In other areas it is little more than a ditch with little gravel, little vegetation and very poor fish and wildlife habitat.

With the planning of the Rock Creek flood control project, county residents, County government, and State and Federal agencies have an opportunity to foster a living stream of salmon, pond turtles, hawks, kingfishers and more. These species are present now in limited numbers. Both Swainson’s hawk and western pond turtles have been observed in the Rock Creek watershed. Some of Rock Creek is channelized, and its sloughs and overflow channels filled and riparian forests cut and converted to orchards. Houses have been built in Rock Creek’s historic flood plain. This has reduced its flood carrying capacity to a minimum. A moderately large storm that has a 1 in 7 chance of occurring in any given year routinely causes flooding. Houses are flooded in the same storms which are relatively small ones on the scale of the possible storms that can occur in Rock Creek. In order to protect Rock creek, protect residents from flooding, and provide habitat, two things must be utilized: public taxes and land. It takes space to hold water. Some land will be needed, it will have to be purchased. Tax dollars must be used. But adjacent property owners will benefit substantially. They will not be subject to flooding as they now are every two or three years.

If the public is to invest millions tax dollars, there must be a return for the public at large, flooding must be prevented, the fisheries, and Rock Creek ‘s existing and potential wildlife should be protected and enhanced. The Chinook Salmon that use Rock Creek for spawning are currently listed as an endangered species. Swainson’s hawks are also found at Rock Creek.

In some areas of Rock Creek there are small levees; in many cases right on the stream banks. Landowners’ property extends into the creek channel and its riparian forest. Some property owners have cut down all of the riparian trees. Some have dumped landscape debris which are then washed into and pollute the creek. Some properties owners use herbicides every year.

These property owners will benefit substantially from the millions of dollars to be invested, protecting their houses and properties. We believe it is right and proper to do this. We also believe it is right and proper to protect the fish and other species of Rock Creek, birds of prey, deer, and the other non-human residents of our creeks.

Other changes need to be accomplished as well. Cattle have been raised on Rock Creek for many years. One property owner has removed his cows yearly in May, while others allow them to remain into the summer. The first property owner now has a well-shaded willow forest growing along the creek. Research shows that willows act as flexible vegetation in storms. They do not block flood waters to any appreciable amount, but they do reduce the force of the water protecting stream banks from erosion.

Project Design

The flood control project must be designed and constructed so as to allow a riparian forest to regenerate, and to allow and encourage gravel to remain in the creek so that salmon can spawn, rear, and migrate out. Property owners and the County need to give up a measure of control inside the levees. They must not cut down stream trees or use agricultural chemicals. The area inside the levees must return to nature as much as is possible. In order to do this, levees need to be set back enough to permit vegetated stream banks and at least a limited natural meandering, in correspondence with Rock Creek’s natural geomorphic conditions.

Part of the project should be a management plan that includes:

  • Recognizing the importance of the stream’s corridor as critical habitat.
  • Including fish and wildlife needs equally with flood protection.
  • Recognizing the value of the geomorphic (the one immediately next to the creek) flood plain for flood storage and the ecological integrity of the creek (as in BLM’s Proper Functioning condition protocol).
  • Mitigating previous cumulative abuse as well as damage created by the project, including permission for concerned groups to conduct restoration plantings.

In the short run, building Rock Creek’s flood control system this way will cost more money. But in the long run, it will cost far less in maintenance and human suffering, and will provide a beautiful greenway. A green strip of water and forest from the foothills to the Sacramento River. Such is the potential of Rock Creek.

In short, the Rock Creek flood management system needs to be designed to accommodate all aspects of a healthy stream including plants and animals.

This is the best investment and long term plan for Butte County as a whole.

From the Winter 2001 issue of the Environmental News.