river bottomとは 意味・読み方・使い方

名詞

river bottom (plural river bottoms)

1. The lowest part of a river, where the water meets the ground below.

   Synonym: riverbed

   Hypernyms: bottom, bed

   Coordinate terms: streambed; creek bed

   • 2004, Verne C. Huser, “Traveling upstream and down”, in On the River With Lewis and Clark (Environmental History series)‎, volume 19, Texas A&M University Press, →ISBN, pages 117-118:

     A poler's feet never leave the deck. The climbing action simply exerts power to the river bottom, an action that moves the craft in an appropriate direction. The power of pushing off the bottom of the river is transferred to the craft through the soles of the poler's feet. It is a technique applied by native people all over the world. As old as the pyramids, poling has been used in Asia, Africa, Europe, and both Americas. It is used today by indigenous people in many third-world countries in their daily lives; it is used as well for river recreation in much of the modern world. It was a common practice in the early nineteenth century. On the Lewis and Clark expedition, when the goal was to move the keelboat upstream, a crew of men in line began at the bow of the boat, which pointed upstream. Each man placed one end of a long pole on the river bottom, the other in his armpit (they did not climb the pole as a solo or tandem poler would), then walking slowly along the catwalk toward the stern, each pushed backwards against the river bottom as he moved forward (downstream), thereby forcing the keelboat upstream. The catwalk created by the locker lids fastened securely in the down position was lost if the lids were raised as a barricade against Indian attack as they were in the expedition's encounter with the Teton Sioux. After reaching the stern each man returned to the bow to repeat the process, hour after hour, all day long if the wind failed to blow or if it came from the wrong direction or grew too strong or too gusty. Poling was hard, grueling work that the men hated, but it was more energy efficient than rowing and better than towing, the technique at the top of the list of unpleasant jobs. The pirogues could be poled as well, the men standing rather than walking, pushing backward against the river bottom, climbing the poles. If the riverbed were too muddy to offer the pole enough resistance, the technique was less effective. Occasionally a pole stuck in the muddy bottom or became entrapped between rocks or in woody debris on the river bottom, leaving the poler the choice of letting go of the pole or clinging to it in the middle of the river as the craft drifted out from under him. (There is no evidence in the journals that any such events occurred, but it seems likely, given my own experience at poling, for it has happened to me. The men often had to make or find new poles because they lost or broke them.) The men of the Lewis and Clark expedition poled the keelboat at times, perhaps more frequently than the journals suggest. They stopped often to find wood to make new oars and poles to replace those broken, worn out, or left behind. They liked ash for oars but for poles no preference is given in the journals. They used abandoned tipi poles, usually lodgepole pine, at least once and found they worked well.

2. The alluvial land along the margin of a river.

   Synonyms: bottomland, bottom, alluvial plain, floodplain

   • 1926, Dane Coolidge, “Chapter 26: The Peace Council”, in Under the Sun [a novel]‎, E.P. Dutton, page 252:

     [Old Humpback:] "Every other day, after we have eaten up our rations, we march through a big door and the man gives us a brass check to exchange at the window for more. Every man, woman and child is given two pounds of meat and two more of flour or corn; and when we would not eat their bacon they sent down to Texas and brought up big herds of steers. We spend our time in singing and dancing and in hunting on the plains, for the white men gave us back all our guns; and in the riverbottom below we have big fields of corn, and squashes, and watermelons, and beans."

   • 2000 February 15, United States Army Corps of Engineers, quoting William B. Newcomb, “Letter from Mr. William B. Newcomb to Mr. Tod D. Smith, Buffalo District, US Army Corps of Engineers”, in Irondequoit Creek Watershed Flood Protection: Environmental Impact Statement‎, United States Army Corps of Engineers, page 38:

     Dear Sir: One of my early recollections is of a flood on my grandmother's farm on the Sangamon river in Illinois. I also recall the optimistic family discussions of the project undertaken by the Army Corps of Engineers to straighten the channel and build levees. The property assessments were substantial, but it was thought that the project would reduce the annual flooding and the risk inherent in farming river bottom acreage. The results were disappointing. The frequency of flooding was reduced, but the severity increased and the rate of drainage was slowed to the point of total crop loss in flood years. The property assessment continues to the present for purposes of levee maintenance and repair. An alternative approach to flood control came to my attention when I read the books on farming written by novelist Louis Bromfield after his return from France to his native Ohio. […] A better solution resulted from a disastrous 1913 flood in the watershed of the Muskingum river, a tributary of the Ohio, which caused much property damage and loss of life. Concerned citizens and local, state and federal agencies cooperated to form the Muskingum Watershed Conservancy District, a publicly owned, self supporting, tax paying corporation. Bromfield describes at length the many benefits provided by the District, which is operated on the concept of upstream impoundment of floodwaters and their gradual release. In his book From My Experience, p263, he says: "There is no longer any doubt about the workability and the great benefits of the [project]. The district has been in operation long enough to prove itself. In the spring of 1947, rains almost as heavy as those of the Great Flood of 1913 descended on the valley. Indeed in the upper reaches the downpour equaled the violence of the 1913 flood rains, and not one cent of property damage occurred, nor was one life lost. The sluices of the great dams were closed and the floodwater impounded and held there, to be let out slowly over the succeeding weeks. There was no need for expensive levees, which in the past often broke and created more damage than if they had never existed." It should be noted that the project was designed, built and operated by the Army Corps of Engineers. I believe that the upstream impoundment concept is equally applicable to the problems of flood control in almost any watershed. If one makes allowances for differences of scale, it should work as well in the Missouri, the Muskingum and the Sangamon. I urge its consideration and adoption for watershed management and flood control in Irondequoit and Allens Creeks.

Further reading

• river bottom on Wikipedia.Wikipedia