Flood-Inundation Maps and Wetland Restoration Suitability Index for the Blue River and Selected Tributaries, Kansas City, Missouri, and Vicinity, 2012

Abstract

Digital flood-inundation maps for a 39.7-mile reach of the Blue River and selected tributaries (Brush Creek, Indian Creek, and Dyke Branch) at Kansas City, Missouri, and vicinity, were created by the U.S. Geological Survey (USGS) in cooperation with the City of Kansas City, Missouri. The flood-inundation maps, accessed through the USGS Flood-Inundation Mapping Science Web site at http://water.usgs.gov/osw/flood_inundation/, depict estimates of the spatial extent and depth of flooding corresponding to selected water levels (stages) at 15 reference streamgages and associated stream reaches in the Blue River Basin. Near-real-time stage data from the streamgages may be obtained from the USGS National Water Information System at http://waterdata.usgs.gov/ or the National Weather Service (NWS) Advanced Hydrologic Prediction Service (AHPS) at http://water.weather.gov/ahps/, which also forecasts flood hydrographs at selected sites.

Flood profiles were computed for each of 15 reaches by means of one-dimensional or two-dimensional hydraulic models. The models were calibrated by using the current stage-streamflow relations at 10 USGS streamgages and documented high-water marks from the flood of June 14, 2010. Hydraulic models were then used to compute water-surface profiles for flood stages at 1-foot intervals referenced to the streamgage datum and ranging from the National Weather Service Action stage, or near bankfull streamflow, through the stage corresponding to, or exceeding, the estimated 0.2-percent annual exceedance probability flood (500-year recurrence interval flood).

The simulated water-surface profiles were then combined with a geographic information system (GIS) terrain model derived from light detection and ranging (lidar) data having a vertical accuracy of less than 0.6 foot and maximum nominal horizontal post spacing of 2.46–3.28 feet to delineate the area flooded at each 1-foot increment of stage. The availability of these flood-inundation maps, along with Internet information regarding current stage from the USGS streamgages and forecasted high-flow stages from the NWS, will 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.

Additional information in this report includes maps of simulated stream velocity for an 8.2-mile, two-dimensional modeled reach of the Blue River and a Wetland Restoration Suitability Index (WRSI) generated for the study area that was based on hydrologic, topographic, and land-use digital feature layers. The calculated WRSI for the selected flood-plain area ranged from 1 (least suitable for possible wetland mitigation efforts) to 10 (most suitable for possible wetland mitigation efforts). A WRSI of 5 to 10 is most closely associated with existing riparian wetlands in the study area. The WRSI allows for the identification of lands along the Blue River and selected tributaries that are most suitable for restoration or creation of wetlands. Alternatively, the index can be used to identify and avoid disturbances to areas with the highest potential to support healthy sustainable riparian wetlands.

First posted January 7, 2015

Revised April 16, 2015