FLOOD-INUNDATION MAPS FOR THE ST. JOHN AND FISH RIVERS IN FORT KENT, MAINE By Pamela J. Lombard 2011 Scientific Investigations Map 3157 ABSTRACT: Digital flood-inundation maps for a 2.5-mile reach of the St. John River and a 2-mile reach of the Fish River were created by the U.S. Geological Survey (USGS) in cooperation with the Federal Emergency Management Agency (FEMA). The St. John River reach extends from 1,000 feet (ft) upstream from the International Bridge in Fort Kent, Maine, to 5,000 ft downstream from the International Bridge. The 2-mile reach of the Fish River extends from just upstream from Mills Road bridge to its confluence with the St. John River in Fort Kent. The inundation maps, which can be accessed through the USGS Flood Inundation Mapping Science Web site at http://water.usgs.gov/osw/flood_inundation/, depict estimates of the areal extent and depth of flooding corresponding to selected water levels (stages) at the USGS streamgage, St. John River below Fish River at Fort Kent, Maine (station 01014000) and the USGS streamgage, Fish River near Fort Kent, Maine (station 01013500). Current conditions at these USGS streamgages may be obtained on the Internet at http://waterdata.usgs.gov/me/nwis/rt/. The National Weather Service (NWS) forecasts flood hydrographs at places that are often collocated at USGS streamgages, such as the two gages mentioned above. Forecasted peak-stage information, also available on the Internet, may be used in conjunction with the maps developed during this study to show predicted areas of flood inundation. For this study, flood profiles were computed for the stream reach by means of a one-dimensional step-backwater model. The model was calibrated using the most current stage-discharge relations at USGS streamgages 01014000 and 01013500, and documented high water marks from a flood in April-May, 2008. The hydraulic model was then used to determine nine stages at streamgage 01014000, and seven stages at streamgage 01013500. Flood-inundation maps in the map library for this report include 29 combinations of flows calibrated to produce the selected stages at the two streamgages. Stages are referenced to the streamgage datums and range from bankfull to approximately the highest recorded water level at the streamgages. The simulated water-surface profiles were then combined with a geographic information system (GIS) digital elevation model (derived from Light Detection and Ranging (LiDAR) data having a 0.6-ft vertical and 3.3-ft horizontal resolution) in order to delineate the area flooded at each water level. The availability of these maps along with Internet information regarding current stage from USGS streamgages and forecasted stream stages from the NWS provide emergency management personnel and residents with information that is critical for flood-response activities such as evacuations and road closures as well as for postflood recovery efforts. DISCLAIMERS: Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also contains copyrighted materials as noted in the text. Permission to reproduce copyrighted items for other than personal use must be secured from the copyright owner. Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and/or contained herein. This data base, identified as SIM 3157, has been approved for release and publication by the Director of the U.S. Geological Survey. Although this database has been subjected to rigorous review and is substantially complete,the U.S. Geological Survey reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the U.S. geological Survey nor the U.S. Government may be held liable for any damages resulting from its authorized or unauthorized use. The flood boundaries shown were estimated based on water stages/flows at USGS streamgages 0101400 and 01013500, St. John and Fish Rivers, Maine. Water-surface elevations along the St. John River from 1,000 feet (ft) upstream from the International Bridge in Fort Kent, Maine, to 5,000 ft downstream from the International Bridge; and for a 2-mile reach of the Fish River extending from just upstream from Mills Road to its confluence with the St. John River in Fort Kent were estimated by steady-state hydraulic modeling, assuming unobstructed flow, and discharges and hydrologic conditions anticipated at these gaging stations. The hydraulic model reflects the land-cover characteristics and any bridge, dam, levee, or other hydraulic structures existing in August, 2010. Unique meteorological factors (timing and distribution of storm) may cause actual discharges along the modeled reach to vary from assumed during a flood and lead to deviations in the water surface elevations and inundation boundaries shown here. Additional areas may be flooded due to unanticipated backwater from major tributaries along the main stem or from localized debris- or ice-jams. The flood inundation boundaries depicted on this map are based on a digital elevation model (Meta data available). Inundated areas shown should not be used for navigation, regulatory, permitting, or other legal purposes. Although USGS intends to make this server available 24 hours a day, seven days a week, timely delivery of data and products from this server through the Internet is not guaranteed. The USGS provides these maps as a quick reference, emergency planning tool but assumes no legal liability or responsibility for any direct, indirect, incidental, consequential, special or exemplary damages or lost profit resulting from the use or misuse of this information. If this series of flood inundation maps will be used in conjunction with National Weather Service (NWS) river forecasts, the user should be aware of additional uncertainties which may be inherent or factored into NWS forecast procedures. The NWS uses river forecast models to estimate the quantity and timing of water flowing through selected river reaches in the United States. These forecast models (1) estimate the amount of runoff generated by a precipitation event, (2) compute how the water will move downstream, and (3) predict the flow and stage (water-surface elevation) for the river at a given location (AHPS forecast point) throughout the forecast period (every six hours over 3 to 5 days). For more information on AHPS forecasts, please see: http://water.weather.gov/ahps/pcpn_and_river_forecasting.pdf CONTENTS: 00README.txt SIM3157.pdf SIM3157_metadata.txt SIM3157_shapefiles SIM3157.kmz SIM3157_map_sheets.zip (sheets 1 through 29 in .pdf format) This report consists of a pamphlet and 29 map sheets, each sheet with data files, and metadata The shapefiles are as follows: SIM3157_shapefiles: BehindLevee_shp.zip Area Protected by Levee 1 through 29.shp (dbf/.prj/.sbn/.sbx/shp.xml/.shx) InunArea_shp.zip Inundated_Area_1 through 29.shp (dbf/.prj/.sbn/.sbx/shp.xml/.shx) VI. INSTRUCTIONS AND DOCUMENTATION FOR U.S. GEOLOGICAL SURVEY SCIENTIFIC INVESTIGATIONS MAP 3157 To access the data: The data files can be downloaded via the web from http://pubs.usgs.gov/sim/3157.The main product is a Portable Document Format (.pdf) map and pamphlet which requires Adobe Acrobat for viewing. Acrobat software runs on a variety of systems, and is available for download free of charge from Adobe at http://www.adobe.com. To access the .kmz files in this report, download and install Google Earth at http;//www.google.com/earth/index.htm. Launch Google Earth, click the file menu and choose open. Locate and select the .kmz file on your computer. Software Required: Adobe Acrobat (6.x, 7.x, or 8.x), or Adobe Acrobat Pro (6.x, 7.x, or 8.x), or the free Adobe Reader (6.x, 7.x, or 8.x), 8.x is preferred.ArcGIS 9.3 preferred, older versions may also work.