Flooding in Flathead County and Kalispell, MT Initiation to Geo-HMS and HEC-HMS Remi Candaele Hydrology - CE394K

Context & Flood Events Characteristics ArcGIS Process Geo-HMS Process Outline Context & Flood Events Characteristics ArcGIS Process Geo-HMS Process HMS Model Future Work Evergreen – Kalispell Suburb - 1995

Context Flathead county subject to flooding Located in northwest corner of Montana State. Total area of 13,614 km² (5,256 mi²), 410 km² (158 mi²) of it (3.01%) is water. As of 2000, the population was 74,471.

Motivations Being familiar with a Hydraulic Model !!!

Flood Events Characteristics Peak Flow : 2 events at 35m3/s Peak Flow : 2 events > 100m3/s

Flood Events Characteristics Flathead Valley Occurring mostly during spring time, Focus on 2 major events : 04/13/1996 04/20/1997 Low Rainfall intensity : computation over a long period, Difficulty : 1 meteorological station and 2 gauge stations. Time Series

Catchments & Streams Delineation Projected Coordinate System : NAD1983_StatePlane_Montana 7 Subwatersheds selected OBJECTID NAME BasinSlope (%) BasinCN BasinLag (hr) Area_HMS (km2) 1 W90 24.89 67.02 5.78 476.79 2 W100 20.58 70.21 8.28 498.30 3 W110 22.92 60.90 5.46 211.40 4 W120 6.39 66.50 1.68 3.83 5 W130 22.06 63.12 6.71 557.40 6 W140 10.09 67.78 8.46 282.61 7 W150 13.08 67.39 5.84 115.68 SubWatershed Characteristics

Reclassification of Land Cover Data downloaded from NLCD Reclassification in 4 main categories thanks to Dr Venkatesh Merwade Land Use Grid Obtained

Soil Data – Characterization of the Soil Type SSURGO (scale 1:24,000) dataset doesn’t cover the entire watershed: use of the Statsgo dataset (1:250000). 4 types of soil: A/B/C/D. Soil B assigned to the unknown soils Classification Type of soil A (low runoff potential) Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These soils have a high rate of water transmission. B Soils having a moderate infiltration rate when thoroughly wet. These soils have a moderate rate of water transmission. C Soils having a slow infiltration rate when thoroughly wet. These soils have a slow rate of water transmission. D (high runoff potential) Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These soils have a very slow rate of water transmission.

CN obtained from SCS TR55 (1986) Curve Number & Grid CN obtained from SCS TR55 (1986) Generation of a CN Grid Statistics Mean : 66.26 Std Deviation : 11.06

Geo-HMS ArcGIS Interface to create input files to HMS Processes River Length River Slope Basin Slope FlowPaths, Basin Centroids HMS Inputs/Parameters Loss, Transform methods by SCS, Route method by Muskingum Time Lag Basin Curve Numbers Selection of the contributing catchments - GeoHMS Interface

Geo-HMS ArcGIS Interface to create input files to HMS Basin Lag in Hours Basin Curve Numbers

Geo-HMS ArcGIS Interface to create input files to HMS Schematic Export to HMS

Running the model under HMS Meteorologic model : Weight gages, Muskingum routing, Time Lag, Time Series.

Results – Calibrating the model Computations for exercising. Next steps : Find accurate numbers for Muskingum routing, Calibration factor : Streamflow = Model

Venkatesh Merwade – Purdue U. Christine Dartiguenave – ESRI Acknowledgments Venkatesh Merwade – Purdue U. Christine Dartiguenave – ESRI Ron Schlagenhaufer – Flathead County Folks : Eusebio, Tyler, Brian & others

Questions ????