Prepared in cooperation with COOPERATING AGENCY(s) Flood-Inundation Maps for the XXX River at CITY, STATE, YEAR [from POINTA to POINTB, STATE, YEAR] By Author, Author, and Author Scientific Investigations Report XXXX–XXXX Department of the Interior
adjusted, as necessary, to account for tributary inflows (table 3). These adjustments were equal (proportional?) to those applied in the currently effective FIS (Federal Emergency Management Agency, YEAR) [Alternatively, “These adjustments were estimated by applying a drainage-area ratio to the main-channel flows.”] Estimated discharges for corresponding stages and water-surface elevations at selected locations, used in the hydraulic model of the XXX River at CITY, STATE. [ft, feet; NAVD 88, North American Vertical Datum of 1988; ft3/s, cubic feet per second] Stage of water-surface profile (ft)1 Water-surface elevation (ft, NAVD 88) Estimated discharge at indicated location, in cubic feet per second At upstream end of study reach Downstream from confluence with TRIB1 Downstream from confluence with TRIB2 10 1,357.82 1,920 3,010 11 1,358.82 2,620 4,120 12 1,359.82 3,490 5,480 13 1,360.82 4,460 7,010 14 1,361.82 5,600 8,800 1Water-surface profiles are 1foot increments of stage, referenced to the gage datum of the U.S. Geological Survey streamgage, XXX River at CITY, STATE (station number xxxxxxxx) Topographic and Bathymetric Data All topographic data used in this study are referenced vertically to NAVD 88 and horizontally to the North American Datum of 1983. Cross-section elevation data were obtained from a digital elevation model (DEM) that was derived from light detection and ranging (lidar) data that were collected during MONTH, YEAR, by NAME OF COMPANY, CITY, STATE. Postprocessing of these data was completed by NAME OF COMPANY on DATE. The original lidar data have horizontal resolution of x.x ft (x.x meters) and vertical accuracy of 0.xx ft (xx centimeters) at a 95percent confidence level for the “open terrain” land-cover category (root mean squared error of 0.xx ft (xx centimeters)). By these criteria, the lidar data support production of 2ft contours (Dewberry, 2012); the final DEM, which was
- water-surface profiles from historic floods (give DATEs) - water-surface profiles from the current Federal Emergency Management Agency study - discrete discharge measurements that were made at miscellaneous sites (table 1) during periods of moderate to high flow [If an existing model was used, cite it and summarize the calibration steps from the original report.] Model calibration was accomplished by adjusting Manning’s n values and, in some cases, changing the channel cross section or slope [include this latter phrase ONLY if XS and slope changes were actually made for the study model; otherwise delete] until the results of the hydraulic computations closely agreed with the observed water-surface elevations for given flows. Differences between observed and simulated water-surface elevations for the xx simulated flows at the USGS streamgage were equal to or less than xx ft (table 4). [And/or “Differences between surveyed and simulated elevations of high-water marks in the study reach for the flood of DATE were less than xx ft (table 5 ).”] [Instead of presenting these latter data in a table, these differences in simulated and observed profiles could be shown in a figure (fig. 2).] The results demonstrate that the model is capable of simulating accurate water levels over a wide range of flows in the basin. Calibration of model to target water-surface elevations at U.S. Geological Survey streamgage on XXX River at CITY, STATE (station number xxxxxxxx). [ft, feet; NAVD 88, North American Vertical Datum of 1988] Stage of water-surface profile (ft) Target water-surface elevation (ft, NAVD 88) Modeled water-surface elevation (ft, NAVD 88) Difference in elevation (ft) 10 618.74 618.73 -0.01 11 619.74 619.71 -0.03