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首页> 外文学位 >Regional impacts of urbanization on stream channel geometry: Importance of watershed area and channel particle size.
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Regional impacts of urbanization on stream channel geometry: Importance of watershed area and channel particle size.

机译：城市化对河道几何形状的区域影响：流域面积和河道粒径的重要性。

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摘要

Urbanization increases impervious surface cover, expands the drainage network, and increases flow velocity, which increases storm runoff, peak discharges and rates of stream channel erosion. Southern California has experienced rapid urbanization over the past several decades and has the potential for stream channel degradation. San Diego County has implemented a Hydromodification Management Plan to protect channels from erosion through monitoring new development projects and their increases in runoff, but no studies have identified the dominant controls and the impact of urbanization on channel geometry. A synoptic survey of 80 field sites by the California Environmental Data Exchange Network (CEDEN) and additional field surveys from 2013-2014 were used to develop regional curves relating bankfull cross sectional area (Axs), width (w), mean depth (d), and discharge (Qbf) to watershed area (Aw ). Regional curves were compared for urban and reference sites and compared to other regional curves developed for southern California. Multiple regression models were used to identify dominant watershed and channel controls on geometry, including Aw, percent impervious cover (I%), mean annual precipitation, underlying geology, longitudinal slope, and hydrologic soil group. For the reference streams, regional curves were most robust for w (p < 0.05) and Axs (p < 0.05). The regional curves for urban streams had substantially larger coefficients in the regional curves, indicating that urban channels have larger w and Axs for a given watershed size. The most predictive variables for w were Aw and I%. Aw is a predictor of Axs only for reference sites; when all sites are included in a regression model, I% was the only predictive variable for all channel metrics, suggesting that urban-induced enlargement in smaller urban channels disrupted the natural Axs-Aw relationship. A majority (68%) of the urban channels were enlarged, defined as a Axs larger than the upper 95% confidence interval of the regional curve for reference sites. Of the enlarged channels, 73 percent were located in small watersheds (<10 km2). Channel response differed by channel substrate. Sand-bedded channels incised, while gravel-bedded channels widened. Sand-bedded channels in small urban watersheds (10 km2). Channels draining larger urban watersheds may be less susceptible to enlargement due to stabilization of channel banks through the establishment of riparian vegetation from increased urban baseflow. Management should focus on monitoring sand-bedded channels in watersheds smaller than 10 km2.
机译：城市化增加了不透水的地表覆盖范围，扩大了排水网络，并增加了流速，从而增加了暴雨径流，洪峰流量和河道侵蚀率。在过去的几十年中，南加州经历了快速的城市化进程，并有可能导致河道退化。圣地亚哥县已实施了一项《加氢改造管理计划》，以通过监测新开发项目及其径流量的增加来保护河道免受侵蚀，但尚无研究确定主导性控制措施以及城市化对河道几何形状的影响。加利福尼亚环境数据交换网络（CEDEN）对80个现场的概要调查以及2013-2014年的其他现场调查被用于绘制与河岸的完整横截面积（Axs），宽度（w），平均深度（d）相关的区域曲线，然后向流域面积（Aw）排放（Qbf）。比较了城市和参考地点的区域曲线，并与为南加州开发的其他区域曲线进行了比较。多元回归模型用于确定主要的分水岭和河道的几何形状，包括Aw，不透水覆盖率（I％），年平均降水量，底层地质，纵坡和水文土壤群。对于参考流，区域曲线对于w（p <0.05）和Axs（p <0.05）最鲁棒。城市河流的区域曲线在区域曲线中具有较大的系数，表明在给定的分水岭规模下，城市河道的w和Axs较大。 w的最可预测变量是Aw和I％。 Aw仅是参考位置的Axs预测因子；当所有站点都包含在回归模型中时，I％是所有渠道指标的唯一预测变量，这表明较小的城市渠道中城市诱发的扩张扰乱了自然的Axs-Aw关系。大多数城市通道（68％）被扩大，定义为大于参考点区域曲线的95％置信区间上限的Axs。在扩大的河道中，有73％位于小流域（<10 km2）。通道响应因通道基板而异。砂层河道切开，而砂砾层河道拓宽。城市小流域（10平方公里）中的沙床河道。由于城市基础流量增加，沿河植被的建立使河岸稳定，排水较大的城市集水区的河道不易扩建。管理人员应重点监控小于10 km2的流域中的沙床。

著录项

  • 作者

    Taniguchi, Kristine Teru.;

  • 作者单位

    San Diego State University.;

  • 授予单位 San Diego State University.;
  • 学科 Geography.;Hydrologic sciences.;Water resources management.
  • 学位 M.S.
  • 年度 2014
  • 页码 41 p.
  • 总页数 41
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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