| Abstract: | After the devastating floods caused by Hurricane Mitch in 1998, maps of the areas and depths of 50-year-flood inundation at 15 municipalities in Honduras were prepared as a tool for agencies involved in reconstruction and planning. This report, which is one in a series of 15, presents maps of areas in the municipality of Nacaome that would be inundated by 50-year floods on Rio Nacaome, Rio Grande, and Rio Guacirope. Geographic Information System (GIS) coverages of the flood inundation are available on a computer in the municipality of Nacaome as part of the Municipal GIS project and on the Internet at the Flood Hazard Mapping Web page (http://mitchnts1.cr.usgs.gov/projects/floodhazard.html). These coverages allow users to view the flood inundation in much more detail than is possible using the maps in this report.
Water-surface elevations for 50-year-floods on Rio Nacaome, Rio Grande, and Rio Guacirope at Nacaome were computed using HEC-RAS, a one-dimensional, steady-flow, step-backwater computer program. The channel and floodplain cross sections used in HEC-RAS were developed from an airborne light-detection-and-ranging (LIDAR) topographic survey of the area and ground surveys at two bridges.
The estimated 50-year-flood discharge for Rio Nacaome at Nacaome, 5,040 cubic meters per second, was computed as the drainage-area-adjusted weighted average of two independently estimated 50-year-flood discharges for the gaging station Rio Nacaome en Las Mercedes, located about 13 kilometers upstream from Nacaome. One of the discharges, 4,549 cubic meters per second, was estimated from a frequency analysis of the 16 years of peak-discharge record for the gage, and the other, 1,922 cubic meters per second, was estimated from a regression equation that relates the 50-year-flood discharge to drainage area and mean annual precipitation. The weighted-average of the two discharges is 3,770 cubic meters per second.
The 50-year-flood discharges for Rio Grande, 3,890 cubic meters per second, and Rio Guacirope, 1,080 cubic meters per second, were also computed by adjusting the weighted-average 50-year-flood discharge for the Rio Nacaome en Las Mercedes gaging station for the difference in drainage areas between the gage and these river reaches. |
| Genre: | USGS Numbered Series |
| ProdID: | 50662 |
| Citation Author: | Kresch, David L.; Mastin, M. C.; Olsen, T. D. |
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| Citation Language: | ENGLISH |
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| Citation Phsyical Description: | 13 p. |
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| Citation Series: | Open-File Report |
| Citation Series Code: | OFR |
| Citation Series Number: | 2002-256 |
| Citation Search Results Text: | Fifty-year flood-inundation maps for Nacaome, Honduras; 2002; OFR; 2002-256; Kresch, David L.; Mastin, M. C.; Olsen, T. D. |
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| Citation Year: | 2002 |
| Type: | citation/reference |
| Text: | Fifty-year flood-inundation maps for Nacaome, Honduras; 2002; OFR; 2002-256; Kresch, David L.; Mastin, M. C.; Olsen, T. D. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/usgs_thumb.jpg |
| URL (INDEX PAGE): | http://pubs.usgs.gov/of/ofr02256/ |
| Date Other: | Tue, 1 Jul 2003 00:00 -0500 |
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