Lab 7: Flood Inundation Modeling

Goals and Background

The purpose of this lab is utilize the LiDAR model created in the previous labs to model flood inundation in the study area. The lab will provide me with hands on experience illiterately modeling flood inundation based on various water heights in the study area.

Methods

Development of a simple flood inundation model

Before creating the inundation model I first have to create a water feature class which I will use in ArcScene to create the model. I used ArcMap to create a polygon feature class approximately the same spacial extent of the study area (Fig. 1).

(Fig. 1) Display of the created water feature in ArcMap.

Next, I opened the DTM I created in Lab 5 in ArcScene. After bringing in the DTM I had to set the Base Heights to Floating on a custom surface and the Factor was set to 2.0 along with changing coloration of the symbology (Fig. 2).

(Fig. 2) Display of the DTM with adjusted base heights and changed symbology.

Next I opened the created water feature in the ArcScene and set the base heights like the DTM but I set the Factor to 1 so it was below the DTM. Then I used the Animation Manager to create a flood animation. I created a new animation Keyframe and I set the Translation:Z to 10 feet below the DTM. I added 19 more Keyframes and increased the elevation by 5 foot increments. I had a few issues with my DTM so I had a hard time getting the exact elevation to be 10 feet below the surface. Then I was able to run the animation.

The animation wasn't perfect as water would come up in the middle of the high ground. To attempt to remedy the issue I edited the water feature in ArcMap and reshaped the feature class so there would be no water in the areas with the issue (Fig. 3).

(Fig. 3) Display of the edited water feature class in ArcMap.

Next I reset and ran the animation again.

Results

Sources

Lidar LAS data for portion of the Chippewa Valley is from The City of Eau Claire, WI. NAIP imagery is from United States Department of Agriculture Geospatial Data Gateway.