areas and facilities while not requiring costly, environmentally damaging structural s0lutions. With better floodplain management, local governments could help people avoid vulnerable areas or relocate out of flood prone locations, both of which would help reduce property damage and threats to life.


Generalized view of watershed impacts associated with logging (from Mount, California River and Streams)

California, of course, doesn't really have any other choices. With more than a thousand darns already built, the state has used up nearly all practical dam sites. Clearly, darns themselves are not the final answer to flood problems; some of the worst flooding experienced has occurred downstream from some of the biggest dams and reservoirs in California.

Without question people will continue to rely on darns and levees for public safety. But to truly improve flood protection and the environment, we must go beyond a traditional belief that we can control all floods, in all places, all of the time.

"Ten thousand river commissions, with the mines of the world at their back, cannot tame that lawless stream, cannot curb it or confine it…cannot bar its path with an obstruction which it will tear down, dance over and laugh at...”

Mark Twain, Life on the Mississippi

Flooplain Management

As opposed to traditional measures for controlling floods such as darns and levees, floodplain management might be viewed as the soft, typically non-structural but very effective approach to reducing the problems of flooding. Identifying appropriate floodplain uses and activities that are compatible with the natural risks means using zoning, subdivision regulations, building codes, health regulations, special ordinances for construction grading and erosion control, watershed management, emergency preparedness, insurance, and other measures to guide people and communities away from potentially disastrous flood problems.

Floodplain management means substituting "management" for "construction" as the most crucial measure for protecting people and property, while at the same time reducing environmental impacts that traditional methods impose.

A Watershed Approach

"Floodplain management can protect people and property while also reducing environmental impacts."

Managing floods also requires good watershed management. Everything we do in a watershed is subsequently reflected in the nature of run-off that occurs when rain falls from the sky. Removal of vegetation on a large scale by clear cut logging or wildfire significantly increases storm run-off for the smaller, frequently occurring flood events (floods occurring about every 20

years or less). Construction of roads increases and funnels surface water flow, accelerating erosion and encouraging gully formation. Hard surfaces created by urban development such as roof tops, parking lots and compacted surfaces also increase runoff and provide a direct avenue for urban pollution into nearby water courses.

When watersheds reach the threshold in terms of cumulative disturbance from roads, logging, and development, the run-off from even a moderately heavy rainstorm can often lead to large land slides, damaging erosion, and sedimentation on a massive scale, as well as downstream flooding.

Intensive road building and logging operations on both public and private lands, coupled with the impacts of wildfire caused by misguided, 100-year-old fire suppression policies, has also led in the past to run-off problems in these watersheds.

To manage our watersheds in anticipation of large storm events means staying out of those few roadless and undeveloped areas that remain in the mountain watersheds. In addition, we should avoid road construction, logging, and development along streams, on unstable slopes, or on highly erosive soils. Other good watershed management principles include managing timber to maintain nearly continuous forest cover and avoiding development in floodplains.

The result of these management measures will be a watershed that acts like a sponge and retains water, rather than shedding rain rapidly and creating siltation and habitat problems in rivers and other problems downstream.