City of Portland and DHI Partner for Presentation on Water Quality Risk Assessment at ESRI Conference

Arnold Englemann of DHI's Portland Office and John Burns, Water Resource Engineer at the City of Portland Bureau of Environmental Services will give a presentation at the ESRI WATER Conference February 10-12 in Portland Oregon. Their paper titled: Water Quality Risk Assessment describes the GIS tool DHI and the City of Portland partnered to create. 

The risk assessment approach in the City of Portland, relies on high-resolution terrain models to route runoff over the surface of the city. The surface runoff model is then linked to a GIS asset inventory of inlets, pipes, and culverts to route stormwater through the piped stormwater network. To deal with a constantly changing and improving asset inventory, all work is performed using GIS automation techniques. This ensures that as the asset inventory improves the latest information will be reflected in the risk assessment.

A combination of Python scripting using ArcPy and ArcObjects/C# was used to create the automation framework. ArcPy is primarily used to automated retrieval and pre-processing of asset data using geoprocessing tools. More advanced analysis, including tracing of flows over and under the surface is done using C# and ArcObjects. Final results are processed into easily understood feature classes and rasters which are uploaded to an ArcGIS Server database for access by all relevant City staff.

This water quality risk assessment is used to identify and prioritize projects to protect public health and the environment and to meet the Portland’s regulatory requirement as part of the municipal separate storm sewer system (MS4) permit.