SGER: Iowa Flood Mapping by Airborne Laser Swath Mapping

PI请求拨款飞越爱荷华河走廊，捕捉2008年中西部洪水的图像。这可能是500年一次的极端事件。飞越计划于2008年6月19日至21日进行，将使用机载激光测绘仔细分析爱荷华州的洪水地区。目标是将基于激光雷达的地图产品与土壤侵蚀模型相结合，以确定提供给流域出口（墨西哥湾）的泥沙负荷，通过制图和现场测量来改进农业用地总氮冲刷的估计，更好地了解洪水流域的排水通道几何形状，并约束排水通道山坡形态，以改进水停留时间模型。这项研究的独特之处在于能够结合大规模高分辨率测绘技术来了解罕见的（可能是500年）洪水事件。利用激光雷达测绘，PI可以将地貌学数据输入到爱荷华河流域的大尺度二维洪水波传播模型中。此外，高分辨率测深数据将与高分辨率自由水面图相结合，以跟踪洪水后主河道形态的变化。最终，高分辨率制图产品将被纳入预测模型，以协助从公民规划到应急响应的各级管理人员。在爱荷华州观测到的洪水强度表明了当前联邦应急管理局100年和500年洪水地图的局限性，主要是由于精度和分辨率较差。高分辨率地图将为管理者提供建模和理解2008年中西部洪水所需的工具，并将为更好地理解河流形态提供基础。数据也将有助于估计流入墨西哥湾的营养物负荷，这可能会影响死亡区的动态。由于每年数十亿美元的损失，更准确的洪水和地貌数据是及时和广泛关注的

0848400ShresthaThe PI requests funding to overfly the Iowa River corridor to capture imagery of the 2008 Midwestern flood ? a potential 500 year extreme event. The overflights are scheduled for 19-21 June 2008 and will use airborne laser swath mapping to carefully analyze flooded areas in Iowa. The objectives are to interface the lidar-based map products with soil erosion models in order to determine sediment load provided to the watershed outlet (Gulf of Mexico), to refine estimates for total nitrogen washout from agricultural lands using both mapping and in situ measurements, to better understand drainage channel geometry in the flooded watershed, and to constrain the drainage channel hill slope morphology in order to refine water residence time modeling. The unique aspect of the proposed research is the ability to combine large-scale high resolution mapping technology to understand a rare (perhaps 500 year) flooding event. Using lidar mapping, the PI may feed geomophological data into large scale two-dimensional flood wave propagation models within the Iowa River watershed. In addition, high-resolution bathymetry data will be coupled with high-resolution free-surface maps in order to follow post-flood changes in the main channel morphology. Ultimately, the high-resolution mapping products will be incorporated into predictive models to assist managers at all levels, from civic planning to emergency response. The magnitude of flooding observed in Iowa demonstrated the limitations of current FEMA 100-year and 500-year flood maps, primarily caused by poor accuracy and resolution. High-resolution mapping will provide managers with the tools needed to model and understand the 2008 Midwestern flood and will provide a basis for better understanding river morphology. Data will also be useful in estimating nutrient loading to the Gulf of Mexico which may impact the dynamics of the dead zone. With billions of dollars lost each year, more accurate flood and geomorphology data are timely and of broad interest.***