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JEFFREY MOUNT’S SEMINAL FLOOD-CONTROL BOOK © Bruce Bledsoe
In the years preceding the devastating 1997 flood and the “living [natural] river” flood project that followed, an attempt was already under way to educate northern Nevadans about the wisdom of restoring the Truckee River to a more pristine state—i.e., to undo the “unnatural” engineering of the United States Corps of Engineers three decades earlier. One of the seminal arguing points in this effort was Jeffrey Mount’s 1995 book California Rivers and Streams.
Mount’s book was disseminated and sold in Washoe County through the efforts of the Truckee River Yacht Club; Mount himself spoke at one of the organization’s annual informational seminars. He was a young geology professor at the University of California, Davis who argued passionately that the traditional method of flood control—confining rivers to narrow, unnatural channels—was a fool’s game, as were the damming, diverting, lining and levying that accompanied it. [Emphasis added]
Mount intended his work as a primer for California, whose rivers were not always similar to those in arid Nevada, but it rang true for Nevadans who saw many of the same follies in their own state. To wit: “We deliberately choose to build our businesses and homes on this state’s floodplains, despite overwhelming evidence that eventually we are going to be flooded. We log, mine, farm, and pave our landscape in a way that increases the magnitude and frequency of floods. And once flooded, we demand expensive engineering solutions that ultimately cannot prevent future flooding or, in some cases, actually exacerbate the problem.”
When new floods inevitably came, he continued, Californians became “perennial mendicants, waiting for federal largesse to save us from our myriad disasters and allowing us to rebuild directly in harm’s way.” If, instead, the state had heeded the reality of the river’s dynamic
geomorphic systems, working with them rather than against them, “we might have spared ourselves much of the calamity that marks the beginning of 1995” when heavy flooding afflicted both northern and southern California.
A considerable portion of Mount’s book is scientifically technical, replete with graphs, algebraic formulas and technical definitions as he explains how rivers function and (under the tutelage of man) misfunction. The reader is taken through the dynamics of sedimentation, the way rivers
shape themselves, their tectonics and geology, the function of watersheds and drainage, and the effects of climate. Nevertheless, the case he builds is easily followed. In brief, here is what Mount says:
Logging proved detrimental, but worse was hydraulic mining in the Sierra that poured huge amounts of sediment into the rivers, plugging them and worsening floods. Government responded not by asking residents to live with nature but by altering it drastically. It did this by dredging rivers to increase their capacity, reconfiguring them into straight-jacket channels that often were lined with cement, building an ever-expanding levee system, and creating hundreds of dams.
Beyond this, and “In defiance of logic,” growth took place “as far removed from water sources as possible,” creating the need for huge and hugely expensive water-transport systems. In response, the federal Flood Control Act of 1936 gave the Corps of Engineers “the green light to spend vast sums to protect all those who chose to reside on the floodplains. Of course, these sums had to be justified on a cost/benefit basis, but that rarely provided an obstacle for the creative economists and engineers of the corps.”
But there were fatal miscalculations in the corps’ unthinking faith in “‘river improvement,’ as if nature just didn’t get it right the first time.”
Dredging proved an illusory safeguard, as rivers often quickly refilled their beds with sediment which drastically reduced the expected flood protection. Channelization, designed to move water faster and more efficiently through the danger zone, inevitably poured more water onto unprotected areas upstream and downstream. So did levees, creating new and greater flooding that led to more demands for flood control. The levees themselves sometimes failed, but more often simply proved inadequate to the job. Many had been designed with just enough freeboard to meet National Flood Insurance Protection limitations for development in the 100-year-floodplain (the area that would be flooded on average once every hundred years).
This was “a recipe for disaster” since the 100-year flood calculations proved illusory as a measurement for safety. In part this was because nature undid some of the engineering, for the
reasons stated above, but also because the engineering data were based on the relatively dry first half of the twentieth century. From the 1950s onward, the climate grew wetter, and the 100-year-flood of 45,000 cubic feet per second became a flood of 112,000 cfs. Beyond that, when 100-year-floods came, they expanded the flood plain. Thus, “it is a virtual certainty that the defined 100-year floodplain—the planning tool of the twentieth century—is not the actual 100-year floodplain at any given point in time.”
In short, each of the engineering solutions exacerbated the imbalances created by urbanization of the watershed. This led, again, to greater flooding and even more extensive engineering solutions.
In his preface, Mount says his book “does not attempt to solve the problems that face California rivers…. There are no recipes for solving land use problems, no designs for mitigating impacts.” His goal is merely to state the problem. Nevertheless, the reader finds a clear message that humans should work with the natural river as much as possible. And Mount does specifically say that levees should be located farther away from rivers in order to let them meander more naturally with riffles, pools and riparian vegetation, creating space for water storage during floods—one of the tactics proposed for the Truckee.
Other Mount dictums include these:
—Every man-made reservoir is filling with sediment, a process that gradually but steadily reduces its storage capacity. Therefore, over several generations, “as every engineer knows, each reservoir in California is ultimately doomed.”
—The removal of riparian (riverbank) vegetation in favor of concrete and riprap is an expensive non-solution because the roots of trees and other vegetation are often just as effective as non-natural engineered solutions in stabilizing the banks.
—Many of California’s water projects were created to irrigate farmland, a particularly wasteful and expensive use of water in a semi-arid state. For instance, alfalfa, pasture, cotton, and rice receive one-third to one-half of the total amount of water used for agriculture, but they earn less than 10 percent of the $20 billion crop income and account for less than 0.3 percent of all goods and services produced in the state. This folly is subsidized by water that is far cheaper than urban water: in some places, $12 an acre-foot compared to $455 to $875 an acre-foot.
These observations by Mount presaged the growing struggle in the West between “wasteful” agriculture and the growing cities that seek the farmers’ water. This ferment could be seen in Reno and Sparks in the late twentieth-early twenty-first century as the two cities eyed the Truckee River water being diverted to farmers in Fallon.
© Bruce Bledsoe