Geomorphic and environmental effects of instream gravel mining
Geomorphic and environmental effects of instream gravel mining
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DOI：
10.1016/0169-2046(94)90010-8
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发表时间：
1994-04
影响因子：
9.1
通讯作者：
G. Kondolf
中科院分区：
文献类型：
--
作者：
G. Kondolf
河道砾石开采涉及直接从河流和溪流的活跃河道中机械清除砾石和沙子。活跃河道沉积物作为建筑骨料是理想的，因为它们通常耐用（在河流运输中已消除了弱材料）、分类良好，并且经常位于市场附近或运输路线上。河道内砾石开采通常会导致河床切割，这种切割可以向上游和下游传播数公里。结果，桥梁和其他结构可能被破坏，产卵砾石消失，冲积水位降低。在分析河内砾石开采的影响时，沉积物预算分析揭示了砾石供应、运输和开采的相对规模。沉积物输送的计算机模型是复杂自然过程的简化；它们可以是沉积物预算分析的有用组成部分，但不应单独依赖。需要对河道变化和沉积物供应进行历史分析，以了解造成当前状况的潜在过程。虽然河内砾石开采可以成为防洪和稳定河流退化的有用工具，但发达国家的大多数河流（当然绝大多数在水库以下）并没有退化，并且更容易受到河内砾石开采的切割相关影响。
Instream gravel mining involves the mechanical removal of gravel and sand directly from the active channel of rivers and streams. Active channel deposits are desirable as construction aggregate because they are typically durable (weak materials having been eliminated in river transport), well-sorted, and frequently located near markets or on transportation routes. Instream gravel mining commonly causes incision of the channel bed, which can propagate upstream and downstream for kilometers. As a result, bridges and other structures may be undermined, spawning gravels lost and alluvial water tables lowered. In analyzing the effects of instream gravel mining, a sediment budget analysis sheds light on the relative magnitude of gravel supply, transport and extraction. Computer models of sediment transport are simplifications of complex natural processes; they can be useful components of a sediment budget analysis but should not be relied upon alone. A historical analysis of channel change and sediment supply is needed to understand the underlying processes responsible for present conditions. While instream gravel mining can be a useful tool in flood control and river stabilization in aggrading rivers, most rivers in the developed world (certainly the vast majority below reservoirs) are not aggrading and are more prone to incision-related effects of instream gravel mining.