Stage-based flood inundation mapping

Abstract

. New methods allow the direct computation of flood inundation maps from lidar data, independently of discharge estimates, hydraulic analysis, or defined cross sections. One method projects the interpolated profile of measured flood levels onto surrounding topography, creating a smooth inundation surface that is entirely based on data and geometrical relationships. A second method computes inundation maps for any simple function that relates the water surface to the elevation of the channel bottom, exploiting their known, sub-parallel character. A final method theoretically combines the elevation of the channel bottom and the upstream catchment area for points along the thalweg, all defined by lidar data. The conceptual simplicity and realism of these maps facilitate databased planning.

Generation and Propagation of an Urban Flash Flood and Our Collective Responsibilities

“…Water depths were greater than those documented for prior floods at all sites along the channel where we have information (cf. Criss and Nelson, 2022;Hauth and Spencer, 1971). Relative to the 2008 flood, the 2022 flood was deeper by about 25 cm in the Olive to Chamberlain reach, by nearly 60 cm at the USGS gauge, and by >100 cm near the tunnel entrance.…”

“…Comparison of this DEM with benchmark elevations and our own GNSS data suggest that the vertical accuracy of this DEM is typically better than ±25 cm, so basin topography is very well known. Criss and Nelson (2022) provided details about this DEM, which they annotated to show the boundary of the River des Peres and several important features. They also described their new QGIS method, used below, to prepare detailed inundation maps using a DEM and flood mark elevations.…”

“…The large tunnels debouch into the open, rocklined channel of the lower River des Peres, a small tributary to the Mississippi River. Criss and Nelson (2022) provided a DEM that showed the entire River des Peres watershed and these various features.…”

“…An inundation map of the 2022 flood was prepared by applying the method of Criss and Nelson (2022) to the data recorded by our in-channel sensors, plus the surveyed levels at > 70 additional points (Fig. 3).…”

Extending Height Above Nearest Drainage to Model Multiple Fluvial Sources in Flood Inundation Mapping Applications for the U.S. National Water Model

“…Due to this fact, evaluation of our relative elevation CFIM method was conducted by comparison to the HEC‐RAS 1D models produced within FEMA region 6 (Base Level Engineering (BLE) Tools and Resources, 2021; estBFE Viewer, 2021; USACE, 2022). This data set was selected due to its large spatial coverage, availability of cross‐sections with streamflow information, higher level of sophistication when compared to HAND, engineering scale detail, and a storied use in the literature as an evaluation data set (Afshari et al., 2018; Bates et al., 2016; Cook & Merwade, 2009; Criss & Nelson, 2022; Follum et al., 2017; Hu & Demir, 2021; Li & Demir, 2022; Li et al., 2022; Rajib et al., 2016; Wing et al., 2017; Wing et al., 2017; Zheng, Maidment, et al., 2018; Zheng, Maidment, et al., 2018). We selected 49 available HUC8s, shown in Figure 7, which span about 185 thousand km 2 across nine states.…”