Like many in the Salmon Creek watershed we suffered considerable damage in the flood of March 1995.
We heard the rain pounding all night. Before the first light I pulled on boots and a slicker. A quick glance at the rain gauge showed that five inches of rain had fallen. Despite the whistling wind I could hear the roar of Salmon Creek. First, check the pump house. Yesterday the pump house stood fifteen feet above the creek and fifty feet back. Today its roof cleaved the rushing current. Lasso it and tie it to a tree? Naw. Maybe it will hold on its own. I circumnavigated the pasture, three feet deep in water, and slogged on towards the Creek House. A fence line had been bowled over and was bobbing and ducking in the torrent. First a fence post breached, followed by a board slap. The flood ran a foot high into the barn; not waiting for an ark to appear, the animals had already moved to higher ground. Salmon Creek was two and a half feet up the foundation of the Creek House. At least the house was elevated, after all it is in the flood plain! In a few minutes the water was six inches above the door. Not much to do now except pray for the water to recede.
By noon the creek had returned to its channel and the sun peeked through the clouds at the sodden countryside. Two fence lines were down. Hay and feed were wet and the barn and house were full of silt. Debris from a storage shed littered the pasture. The pump house had disappeared. So had 500 sq. ft. of pasture. Numerous fresh cuts delineated the new creek bank. A host of trees had uprooted. In the chocolate colored creek, our neighbors' stepladders, tires, water troughs, and soil raced to the ocean.
The flood gave us a keener understanding of Salmon Creek. My wife's and my concern about protecting our property from future floods prompted us to learn more about riparian environments and creek dynamics. We found out that the qualities that make a creek a healthy, functioning natural habitat are the same elements that mitigate flood damage.
Streams will flood. The biggest dams and the highest levees haven't been able to prevent this act of nature. At times structures may contain or lessen the damage from minor events. But in extreme flood conditions, heavy precipitation on saturated soils, manmade structures can exacerbate the flood peaks or divert the water's force elsewhere . Because of the relatively small size of Salmon Creek's watershed it doesn't take long for a flood to crest. There is no two-day warning, as on the Russian River.
Floods happen where there is no impact from man, but roads and their associated ditches, roofs, soils bare from construction or overgrazing, and deforestation, all contribute to faster runoff, higher peak flows and increased erosion. On a per acre basis, small parcels probably contribute more to flooding than ranches. Knowing that we have to live with periodic flooding, each of us can help lessen the impact by paying attention to drainage patterns and land uses. One important key is vegetation which slows down runoff and allows the soil to absorb and retain more water.
We started by talking with representatives from the Natural Resource Conservation Service (NRCS), the Department of Fish and Game (DFG), the Gold Ridge Resource Conservation District (GRRCD) and private consultants. A lot of information was also garnered from a watershed meeting in Bodega and a Sonoma County Farm Bureau conference. We discovered plenty of resources available to design and fund projects that improve land use practices which enhance water quality and thus fish habitat. Funding is available to help the fish and hence the means to achieve our goals. Win-win.
With support from GRRCD and Bodega Land Trust we received two grants for creek restoration and habitat enhancement. GRRCD, DFG, and the NRCS provided a lot of technical advice. We also received help from Americorp volunteers, friends and neighbors.
The NRCS and DFG encourage and fund environmentally sound livestock management practices, such as exclusionary fencing, revegetation, vegetative buffer strips, stream bank protection, controlled access, alternative water development, and prescribed grazing. Implementation of any of the above should improve both water quality and range productivity over the long haul. Both the fish and the landowner benefit.
We built exclusionary fencing along the creek. The fencing decreased the area of available pasture but we think that this loss will be offset in the long run by bank stabilization. Livestock had other sources of water and did not depend on access to the creek. For other ranchers, grazing riparian pastures with careful control of timing and duration, may be a beneficial alternative. We also began to practice rotational grazing to maximize productivity, reduce erosion and allow more water absorption. We found that revegetation was an effective and inexpensive way to stabilize the creek banks. Roots hold the soil together and prevent it from washing away. If given a chance, plants readily grow in a riparian corridor where water is most plentiful during the dry months.
 Figure 1. Willow revetment construction. |
Much of the stabilization and revegetation was in the form of willow revetments (figure 1). The structure of the wall stabilizes the bank until the roots of the growing willows incorporate into the soils. Willow revetments are inexpensive to build and the raw material is readily available. Individually, willow cuttings will take root and provide a quick and cheap method of revegetation (figure 2). We also discovered that ninebark and dogwood will grow from cuttings. Native blackberries and rushes were transplanted. We used a few container plants. To get a sense of what plants are natural and will do well, just look around. But even hearty native species require watering and care their first couple of years. Browsing by deer or livestock can quickly set back efforts.
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Fish require cool, good quality water, year-round pools in which to mature, clean gravel beds for spawning, cover from predators, and a food supply. By stabilizing the stream bank through revegetation and by more carefully monitoring our grazing practices we reduced the amount of sediment entering the creek; created a more favorable environment for insects (food); developed shade canopy; provided woody debris and roots for cover; and helped protect our land from the adverse effects of flooding. What we needed, the fish needed. Win-win squared.
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 Figure 2. Willow sprig planting. Sprigs 2 1/2 to 3 ft. in length, 3/4 in. diameter, trim all branches. |
 The energy of flood flows dissipates over the flood plain. The sediment deposited fertilizes pastures. Vegetation stabilizes the stream bank and maintains a high water table.  Floods are largely contained by the channel which must erode to accommodate the force. The water table lowers. Figure 3. The effect of downcutting and widening of a stream channel on flood flows, the water table, and vegetation. |
A stable, vegetated riparian corridor maintains a higher water table and thus supports more vegetation than an eroding creek that downcuts and widens. A deeper and wider channel would temporarily provide more capacity for storm flows but by its very nature it also lowers the water table, supporting less vegetation, and leaving the land more susceptible to erosion (fig, 3).
Vegetation along a creek does contribute a little bit to flooding by restricting the flow of water. But, if we agree that creeks will always flood, the stabilization of creek banks provided by plants easily offsets any disadvantage. Vegetation along the creek also protects against erosion where minor drainages enter. Sufficient vegetation limits the erosive force of receding flood waters pouring off the flood plain and back into the channel.
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I've heard the argument that trees along creeks cause the bank to erode when they uproot and fall over. This can and does happen, especially when streams have downcut and flood energies cannot easily dissipate across the flood plain. Where stream bank blowouts are common along a stretch of stream, either the banks are poorly protected by a vegetative armor or the stream has downcut and undermines even the healthiest vegetation. The loss of one tree in a riparian corridor in good condition with a continuous belt of vegetation is negligible. The root mass of neighboring trees arrest erosion and prevent formation of a larger cavity. The small amount of erosion caused by the uprooting of a tree is compensated for by its roots having curbed erosion for a number of years.
Downed trees and logjams can cause the diversion of water into stream banks and the consequential scouring. But large woody debris in the creek provides essential protective habitat for fish. As stated above, an extended area of vegetation along a creek decreases the erosive impact of a blowout. On our project we disassembled the upper parts of logjams to lessen the potential for blowouts. Logs that extended beneath the surface were left in place to provide habitat. Downed trees were turned parallel to the current and bolted or cabled in place. We even plan to add anchored logs!
In response to the argument that a restored riparian corridor will diminish the amount of pasture availabile for livestock, I say that the pasture may not be there to graze in a few years if erosion isn't controlled. Have you ever calculated the amount of forage in a gully? It is mainly air. Headcuts in gullies are relatively easy to fix in their early stages, but can quickly grow into insatiable soil eating monsters that are costly to repair.
There is also the claim that trees compete with grasses for groundwater. Tree roots pull water from deep in the ground. We're lucky if our grass roots extend eight inches deep. Many trees are still dormant in the early growing season leaving water available for grass. While it is true that surface moisture moves down to replenish deep soil moisture, annual grasses mature before this effect is perceptible. I have also noticed that some of our lushest pasture is underneath trees where the shade retains morning dew and prevents continuous sun from drying the soil. Trees also serve as windbreaks which lessen the drying effect of the wind.
Periodic flooding of lowlands deposits sediment and minerals that increase the fertility of pastures. One can take advantage of this natural fertilization process by leaving enough residual dry matter or allowing sufficient new growth to slow down flood flows. Over-utilized pasture land may suffer erosion instead of deposition. The same practices benefit upland pastures by lessening erosion and increasing water absorption.
While studying the endangered humpback chub in the Grand Canyon, I was often asked, ìWhat good is that fish? It's not very edible, it doesn't provide fantastic life-saving drugs from its swim bladder.î I had to answer that I wasn't quite sure, but I did know that it was one of God's creatures and its health and presence is an indicator of the quality of life we all lead. The fish in Salmon Creek could be eaten if there were enough of them. More important, I feel they serve as a gauge that we can use to measure our efforts as stewards of the land that has blessed those before us and will bless those to come. As we have learned, a healthy riparian environment contributes to productive pastures and flood damage mitigation in an interactive dependence, which benefits both man and fish (figure 4). If we can do a little to help the fish, I believe we do a lot to help ourselves.
To undertake creek restoration requires some appreciation for the natural resources of a watershed and the willingness to put in one's own time. It pays off by helping maintain the land value over the long haul and it is enjoyable to tinker around and see the results. Voluntary action now may prevent future mandatory land use restrictions aimed at preserving some little fish at whose purpose we wonder.
| Table of Contents | "Stream Restoration Fish and Landowners Win-Win Situation" |
"The Fish and The Watershed" |
More Articles | Willow Revetment Restoration Project |
The Map | Some Project Photos |
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