Flood Risk Assessment in QGIS

Purpose

The purpose of this tutorial is to demonstrate the process of performing a flood risk assessment within QGIS and some primary processing using ESRI's ArcMap.

Data and Software Requirements

In order to begin this tutorial a download of the QGIS software is needed. The current version is QGIS 2.18.15 'Las Palmas' and was released on 08.12.2017. QGIS is available on Windows, MacOS X, Linux as well as Android. This can be found at QGIS Download

Moving forward, the data that will be used for this tutorial can be found from the MacOdrum Library. You may use whatever additional base layers you might like to add to this tutorial, but for this purpose, only roads, buildings, and water body data is used.

The elevation data used in this tutorial can be found here. Four grid point shapefiles were downloaded from the available array of data

After all the data is downloaded, you may proceed to process the files in ArcMap.

ArcMap Processing

In order to create the proper DEM file needed to process the desired outcome of this tutorial, the four grid files previously mentioned must be loaded into ArcMap and then processed into DEMs using the Spatial Analyst tool: Inverse Distance Weighted (or IDW for short).