Flood control

“ We draw the waters from our great number of immense reserve storage reservoirs, which are directly diverted to them from the run-offs of heavy river water flows. Saving us from overflowing rivers, flood control, levee construction, inundation damage, and disasters, at the same time increasing generating power of our dams. We have an efficient drainage system for our tropical crops in rain-soaked lands, excess waters of which also flow into these reservoirs. Sun rays are available to treat our vegetation, when necessary. ”

“ The run-off is increasing every year as we cut our forests and cultivate our land. It is used for navigation, irrigation and power, but the increase is not an advantage for these purposes as might be supposed, because it comes in disastrous [Pg 88] floods, tearing away dams, ruining power sites, and not only preventing navigation during the flood season, but by filling up the rivers and changing the channels, making navigation difficult and dangerous throughout the year. The run-off is controlled to some extent and may be brought under almost as complete control as may be desired. ”

“ They demonstrate tha in operation of the dam the several functions will be interdependent and that the conflicts between the respective requirements of flood control and power development are here more apparent than real. [56] They show that this is nonetheless a flood control project which will 'fully control the maximum flood of record', [57] though power, it is hoped, will pay the way. Whether the work of flood-control, including river flow, would be better done by a dam of one design or another is for Congress to determine. ”

“ We must push forward the development of our rivers for power, irrigation, navigation, and flood control. We should apply the lessons of our Tennessee Valley experience to our other great river basins. ”

“ It would have thrived, however, to a far greater extent and much suffering, involving general living and business conditions, would have been avoided and a better foundation provided for future generations, if, in addition to the above-named developments, attention had been promptly and thoroughly given to the control and conservation of flood water. ”

“ For construction of waterworks on other rivers and lakes, the administrative departments for water resources of the local people's governments at or above the county level shall, before the feasibility study reports of the waterworks are submitted for approval and within the limits of their administrative powers, examine whether the waterworks conform to the comprehensive river basin plans, write down their comments and sign. Where a waterwork is related to flood control, it shall be constructed in accordance with the relevant provisions in the Flood Control Law ”

“ No one may, in areas under river course control, put up buildings or structures that block the passage of flood water, or engage in activities that adversely affect the stability of the river condition or endanger the safety of the river embankment or other activities that block the passage of flood water through the river course. ”

“ It is probable that any successful national work for the control of rivers will have to start with the idea of utilizing some of these natural reservoirs. The lands would not be317 habitable of course, but for agriculture they would be enriched instead of, as now, devastated. ”

“ The victims of economic wrongs due to cupidity and indifference outnumber a thousand to one the victims of natural causes beyond control. All the deaths in these fearful floods are less than those caused every year in a single large city by conditions that might be remedied. ”

“ So near to disaster do the floods approach oftentimes, that every element which the engineers can control is considered a necessary ally in cooperation for the protection of the levees. During the 1903 flood, the river boats were required to run at a reduced speed along a portion of this basin front. ”

“ These subterranean passageways frequently are the cause of serious breaks in canals, through which the flow of irrigation water is diverted and wasted to flood adjacent lands, destroying valuable crops, and indirectly ruining others by causing delays in delivery of water. ”

“ The shade trees that stood in the streets so trim and beautiful are all bedraggled and bent, their branches festooned with floating wreckage and all manner of offensive things, their leaves sodden, their trunks caked with mud. The streets are seas of yellow ooze. Garden fences and hedges are twisted or torn away. Reeking heaps of indescribable refuse lie moldering where there were smooth lawns and bright flower beds. The houses that stand are all smeared with the dirt that shows the height of the flood. ”

“ Year after year a hundred thousand levee builders, with forty thousand teams of mules or so, and operating huge dredging-machines, repair the damage of the spring tides, build new levees, raise old ones, and pave the banks with revetment—great Willow-tree carpets or rugs covered with broken stone to keep the flood in bounds by stopping the washing away of the soft river banks and the undermining of the protection. ”

“ Such a quick rise will cause one body of flood-water to extend for forty or fifty miles in succession, with a width varying from a quarter of a mile to a mile; but it stays sometimes for six weeks, or even two months, upon the ground. And those floods come down with an alarming power and velocity—bridges which have stood for a century are washed away, and districts where floods were previously unknown have became liable to their sudden periodical inundations. The land being wholly in meadow, suffers very heavily from the destruction of its hay. ”

“ The second plan for prevention of flood damages involves provisions for letting the flood water out rapidly by removing obstructions to its flow by straightening and deepening the channels and providing long embankments, dikes, or levees which rise above the ordinary river level to a height exceeding that of the stream during its highest floods. ”

“ All rivers in densely populated countries should [441] have their flood waters stored in capacious reservoirs, with proper sluices, in the main or adjacent subsidiary valleys, so that during the dry seasons there may be always an ample supply of good water for domestic and agricultural purposes, irrigation, and navigation. The reservoirs will also be advantageous in preventing the too frequent inundations and consequent devastation caused by floods. ”

“ In the treatment of the flood problem, prevention, by the use of storage reservoirs, for the purpose of holding back the damaging part of the flood water, is the rational and comprehensive method, as it goes to the source of the trouble, and extends its benefits throughout the entire river valleys, not only in the form of flood relief, but by improvement of the low-water flow, due to the release of the impounded flood waters during the dry season. ”

“ Stream water comes from the surface of the land or out of its porous underlayers, then flows seaward through its creases and folds, affecting the land and the land's creatures along the way and being affected by them. Thus, as we have already noted in more than one way, the management of land and the management of water are closely intertwined, from the way human use of a flood plain may demand structural interference with a river's old habits, to the way erosive farming in some West Virginia valley may help to make it harder to navigate Swedish newsprint into Alexandria by ship. ”

“ The presence of a forest on a watershed tends to give the stream which rises thereon its daily supply of water, whether it rains every day or not. By checking evaporation, the forest swells the volume of sea-going water in this stream, and thereby increases its water-power and makes it more useful as a deep waterway. Forests so regulate stream-flow that if all the watersheds were forested but few floods would occur. Forest-destruction has allowed many a flood to form and foam and to ruin a thousand homes. A deforested hillside may, in a single storm, loose the hoarded soil of a thousand years. ”

“ These floods are succeeded by periods of drought. The flow of water in the streams shrinks away, often leaving their beds almost dry. As a consequence, crops and herds suffer, the mill-wheels are stopped or turn but slowly and feebly, the transportation of merchandise is impeded, and the various industries of life suffer. The forests prevent such a deplorable condition of things. The spongy soil formed by their fallen leaves, accumulated for years, retains the rain which falls upon it as in a great reservoir, and obliges it to flow off gradually instead of with a sudden flood. ”

“ Pile dwellings and house-boats are a paltry form of encroachment upon the water in comparison with that extensive reclamation of river swamps and coastal marshes which in certain parts of the world has so increased the area available for human habitation. The water which is a necessity to man may become his enemy unless it is controlled. The alluvium which a river deposits in its flood-plain, whether in some flat stretch of its middle course or near the retarding level of the sea, attracts settlement because of its fertility and proximity to a natural highway ”

“ It is as right for the National Government to make the streams and rivers of the arid region useful by engineering works for water storage as to make useful the rivers and harbors of the humid region by engineering works of another kind. The storing of the floods in reservoirs at the headwaters of our rivers is but an enlargement of our present policy of river control, under which levees are built on the lower reaches of the same streams. ”

“ The failure of the United States to build on the east bank of the river along the minor basins which we have fully described, a line of levees so as to afford means of protection from the increased danger of overflow arising from the fact that the lines of levees along the river on the west bank and elsewhere had been raised and strengthened and extended, thus, at least, beyond doubt, temporarily increasing the level of the flood in times of high water. ”

“ When the rains fall upon the open, unwooded country, unless it is of a quite level character, they flow off at once into the beds of the neighboring streams, and pour their united flood into the larger rivers, swelling their volume rapidly to such an extent that their waters can not be confined within their banks, but break out and overspread the adjacent lands, carrying destruction oftentimes to the growing crops, covering fertile fields with masses of gravel and rubbish of various sorts, interfering with manufacturing interests, and often destroying life itself. ”

“ The idea of preventing the formation of floods by controlling those original causes, preserving forest and woodland cover, preserving the porosity of the soil, slowing up the run-off from the watershed, or holding back the flood waters in reservoirs or storage basins, seems to be beyond the scope of the powers of conception and construction of the military engineers of the United States Army. They see only results, and seem unable to comprehend original causes. ”

“ It is quite common for millions of cubic feet of water to run over the falls and dams in the streams during these spring freshet periods which, if it could be stored until the drier summer and fall months, would be of wonderful utility in not only maintaining a higher rate of flow in those dry months, but also doing away largely with the damage and inconvenience incident to the sudden run-off of flood waters in their natural condition. These conditions point to the necessity for large water storage reservoirs as the only practical means of accomplishing any considerable degree of regulation. ”

“ If levees are constructed, it is found that the bed of the stream rises also, so that the situation is not materially changed. If channels are deepened, the fury of the floods is increased. If the construction of reservoirs is proposed, there are very important questions of location and danger. ”

“ Stringent prohibitions with regard to refuse, the enlargement of sluice-ways and the compulsory raising of their gates for the passage of floods, the removal of fish-traps which are frequently blocked up by leaves and floating rubbish, a reduction in the number and width of the piers of bridges when rebuilt, and the substitution of movable weirs for solid weirs, greatly facilitate the discharge of a river, and consequently lower its flood-level. ”

“ Floods resulting from heavy rains are likely to be greatest where the slopes above the drainage lines are on the whole greatest, for this is the condition under which the water is most quickly gathered into the drainage channels. The most disastrous floods, humanly speaking, are those which affect wide-bottomed valleys, where the flats are settled. In such cases a relatively slight rise may flood very extensive areas. In such valleys the most disastrous floods are generally in the spring, when the waters from the melting snows of the preceding winter are being discharged. ”

“ Important public works have done much to prevent repetitions of these inundations, but the danger still exists, and always, in a wet season, there are those dwellers along the river's banks who fear the rising flood as they would the plague. ”

“ To produce a flood the rainfall must be heavy and widely distributed, and to produce a flood of exceptional height the duration of the rainfall must be so great that the flood waters of the most distant affluents reach the point considered, simultaneously with those from nearer points. The larger the catchment basin the less probable is it that all the conditions tending to produce a maximum discharge should simultaneously occur. Further, lakes and the river bed itself act as storage reservoirs during the rise of water level and diminish the rate of discharge, or serve as flood moderators. ”