Collaborative Research: The Hydrology, Hydraulics and Hydrometeorology of Flood Response in Urbanizing Drainage Basins

0208225Miller 将通过分析巴尔的摩大都市区的洪水响应来检验控制城市化流域洪水的综合水文、水力和水文气象过程。 科学问题是：（1）对于暖季雷暴系统，城市流域的尺度相关洪水响应如何依赖于降雨的时空结构？ (2) 洪水响应如何随地表特性（包括不透水覆盖层和城市排水网络结构）的变化而变化？ (3) 与河道漫滩形态的地质控制相比，由于城市化而改变的河道/漫滩形态在确定洪水波衰减方面的相对作用是什么？ 问题1和2将通过对1996年至2003年期间24个小于200平方公里流域的25至30次洪水事件的水文和水文气象分析进行研究。 洪水事件的降雨和流量观测的诊断分析将与模型分析结合使用，以解决问题 1 和 2。水文模型分析将基于分布式水文模型，即网络模型。 将对 24 个流域的一部分进行洪水波传播的水力分析，其中包括 4 个河段，每个河段都有上下游对的测流站。 二维深度平均水力模型 TELEMAC 将用于评估城市化河道洪水响应的水力控制。 本研究中使用的关键观测数据包括：(1) 高分辨率（1 km，5 分钟）雷达降雨量估计，(2) 高分辨率（0.6 m 等高线间隔）地形数据集，(3) 来自机载雷达的高分辨率（0.6 m 网格，0.15 m 垂直分辨率）地形数据集，(4) 不透水覆盖层的高分辨率（1 m）表示，以及 (5) 现场测量的河道横截面、纵向剖面和卵石很重要。

0208225MillerThe integrated hydrologic, hydraulic and hydrometeorological process that controls flooding in urbanizing drainage basins will be examined through analyses of flood response in the Baltimore metropolitan region. The science questions are: (1) How does the scale-dependent flood response of urban drainage basins depend on the space-time structure of rainfall for warm season systems of thunderstorms? (2) How does flood response vary with land-surface properties including impervious cover and structure of the urban drainage network? And (3) What is the relative role of changing channel/floodplain morphology due to urbanization, as compared with geologic controls of channel floodplain morphology, in determining the attenuation of flood waves? Questions 1 and 2 will be examined through hydrologic and hydrometeorological analyses of flood events in 24 drainage basins smaller than 200 km2 for 25-30 flood events during the period 1996-2003. Diagnostic analyses of rainfall and discharge observations for the flood events will be used in conjunction with model analyses to address questions 1 and 2. Hydrologic model analyses will be based on a distributed hydrologic model, the Network Model. Hydraulic analyses of flood wave propagation will be carried out for a subset of the 24 basins and will include 4 stream reaches, each with upstream-downstream pairs of stream gaging stations. The 2-d depth-averaged hydraulic model, TELEMAC, will be used for assessing hydraulic controls of flood response in urbanizing stream channels. The key observations used in this study are: (1) high-resolution (1 km, 5 minutes) radar rainfall estimates, (2) high-resolution (0.6 m contour interval) topographic data sets, (3) high-resolution (0.6 m grid, 0.15 m vertical resolution) topographic data sets derived from airborne radar, (4) high-resolution (1 m) representations of impervious cover, and (5) field-surveyed channel cross sections, longitudinal profiles and pebble counts.