On the Persistence of Landscape Features Formed by a Large Flood
On the Persistence of Landscape Features Formed by a Large Flood
复制标题
论大洪水形成的景观特征的持续性
DOI：
10.2307/621860
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发表时间：
1977
影响因子：
3.3
通讯作者：
A. Calver
中科院分区：
文献类型：
--
作者：
M. Anderson;A. Calver
对重现时间间隔较大的洪水形成的景观特征的持续性进行了评价。对埃克斯穆尔部分地区的景观进行了两个时期的研究：1952年洪水过后和现在。证据表明，洪水造成的河道加深将在洪水事件的平均复发间隔内存活下来，而河道一侧的侵蚀伤痕将不会这样：洪水发生时沉积的下游巨石田将倾向于成为一般的洪水平原特征，而不是特定的洪水沉积特征。更广泛地说，这类事件之间的顺序和到达间隔时间，而不仅仅是它们的平均频率，在它们对景观形态和发展的控制方面比迄今所承认的更重要。本文研究大型地貌事件和小而频繁的地貌事件在景观中的相对重要性。它特别关注与1952年8月发生在英格兰西南部埃克斯穆尔的大洪水有关的河流和山坡特征的持续程度。人们已经认识到，地貌过程的影响取决于它们的频率和大小(Wolman和Miller，1960)，特定的地貌特征可能与其规模和频率导致其在一段时间内完成大部分总工作量的事件有关。例如，通道形式的各个方面与主导放电有关的想法早就存在(例如，参见Inglis(194i))，而这种放电今天经常与岸满放电联系在一起。然而，根据其大小或性质，一些景观特征必须是非常大的事件的产物：在这些类别中，必须考虑到非常大等级的碎片的移动，例如，高谷边悬崖的侵蚀。当然，对地貌事件大小的整个频率分布知之甚少。在水文学和气候学文献中都存在预测模型，它们建议从小测量事件的重现间隔直接外推到大事件的重现间隔。一些大型洪灾事件在发生后不久就进行了调查。有代表性的文章有伍利(1946)、雅斯(1947)、沃尔曼和埃勒(1958)、特里卡特(1961)、麦克弗森和兰尼(1969)、汉威尔和纽森(1970)以及古普塔和福克斯(1974)。这些论文中有许多论述了高降雨量的气象原因、洪水通过期间或之后不久观测到的地貌或地质特征，以及高径流的原因，在某些情况下，是从某种洪水控制或预测的角度出发的。本文关注的是洪水所产生的景观特征的持续程度。现有的关于与大洪水相关的地物耐久性的信息是有限的，主要是理论或推测的评论(例如，Gilbert，1890年；Woolley，1946)或在243的描述中本内容从星期六下载，2016年5月21日06：12：50 UTC所有使用受http://about.jstor.org/terms 244 Malcolm G.Anderson and Ann Calver Area of Rockof：an oh Constration...e...ic.B und Rie(eanGRIT a H N1 303 Lynton agwothyBEDS Location 6 Watr WterNORTH Exmoor 00 Hangman AR Gain of Cannon Hill Valley\参考图3 Morte 0--Lates主要山谷/收缩300.-地质边界，1910)C__“t”-300米0 2 4 6公里r\n 0 1 2 3 4米，i，......0，
An assessment is made of the persistence of landscape features formed by a flood with a large recurrence interval. The landscape of part of Exmoor is studied at two dates: following the passage of the 1952 flood and the present day. Evidence suggests that channel deepening resulting from the flood will survive the mean recurrence interval of the flood event, while channel-side erosional scars will not do so: downstream boulder fields deposited at the time of the flood will tend to become a general flood-plain feature rather than a specific flood-deposition feature. More generally, it is suggested that the sequence and inter-arrival times between such events, rather than their mean frequency alone, are more significant in their control on landscape form and development than has hitherto been acknowledged. THIS paper is concerned with the relative importance of large infrequent geomorphic events and smaller more frequent geomorphic events in the landscape. It centres in particular on the degree of persistence of fluvial and hillslope features associated with the large flood which occurred on Exmoor, south-west England, in August 1952. It has been recognized that the effect of geomorphic processes depends on their frequency as well as their magnitude (Wolman and Miller, 1960), and that specific landscape features may be related to the event whose size and frequency cause it to accomplish most total work over a period. For example, the idea that aspects of channel form are related to a dominant discharge has long been in existence (see, for example, Inglis (194i)), and this discharge is today frequently associated with bankfull discharge. Some landscape features however, must, by their size or their nature, be the work of unusually large events: in these categories must be considered the movement of very large grades of debris, for example, and the erosion of high valley side bluffs. Little is, of course, known about the whole frequency distribution of sizes of geomorphic event. Predictive models exist in both hydrological and climatological literature which suggest direct extrapolation from the recurrence interval of small measured events to the recurrence interval of large events. A number of large flood events have been investigated shortly after their time of occurrence. Representative of many articles on such work are those of Woolley (1946), Jahns (1947), Wolman and Eiler (1958), Tricart (1961), McPherson and Rannie (1969), Hanwell and Newson (1970) and Gupta and Fox (1974). Many of these papers deal with the meteorological causes of high rainfalls, with geomorphological or geological features as observed during or shortly after the passage of the flood, and with causes of high run-off, in some cases from the point of view of some measure of flood control or prediction. In this paper attention is focused on the degree of persistence of the landscape features produced by a flood. Existing information on the durability of features formed in association with large floods is limited and found mostly as theoretical or speculative comment (e.g. Gilbert, 1890; Woolley, 1946) or in description of 243 This content downloaded from 207.46.13.111 on Sat, 21 May 2016 06:12:50 UTC All use subject to http://about.jstor.org/terms 244 MALCOLM G.ANDERSON AND ANN CALVER Area Valley of Rockof:an oH Constriction ...e...ic..B und rie (eanGRIT a H n1 303 LYNTON agwothyBEDS LOCATION 6 Watr WterNORTH EXMOOR 00 HANGMAN AR gArea of Cannon Hill Valley \ referred to in Figure 3 MORTE 0--SLATES Principal Valley /Constrictions 300.-Geological Boundaries (after Hamling, 1910) C__ " t"-300Height in Metres 0 2 4 6 Kmns r\ n0 1 2 3 4 Mis ,i , ...... 0 ,