Salt Lake City Selects WaterGEMS and HAMMER

Brandon Arnold, GIS specialist at Salt Lake City Department of Public Utilities, said that their first priority when selecting water modelling software was to make sure the water model could be integrated with the City's GIS and maintained or updated easily. The city chose Bentley's WaterGEMS and HAMMER due to the software's ease of use and full interoperability with Esri's ArcGIS.

The new water model was built from scratch using WaterGEMS and the city's GIS. Once the pipe layout and connectivity were established, the software's LoadBuilder and TRex tools, which are common to both applications, were used, respectively, to allocate water demand and elevations to the hydraulic model's nodes. Pressure reducing valve (PRV) settings were imported from the GIS, and pump curves and controls were added.

Arnold continued, "WaterGEMS' Network Navigator and Pressure Zone Manager were extremely helpful in picking out the small system details and locating the few errors that existed. With 55 zones modelled, which include more than 38,000 pipes, the Salt Lake City water system can be a little overwhelming at times. The Pressure Zone Manager was great for zone-by-zone analysis, and it also made model building much more efficient. Tracking down a missing closed valve sometimes can be tricky. With the Pressure Zone Manager, it is easy to tell where the zones are connected. Once the zones have been established, the data that the WaterGEMS model calculates and displays, including the boundary nodes and total flow into and out of the zones, is very helpful. Overall, the model building process was relatively simple."

Now that the city has a working and up-to-date water model, its hydraulic analyses can include fire flow analysis, pipe sizing for new design projects, and some master planning. Many of the city's ongoing projects rely heavily on the use of the WaterGEMS model. Future projects will be particularly challenging since model assumptions evolve as population grows, the distribution system expands, and the pipe infrastructure ages. For these reasons, both the GIS and water model need to be kept up to date.

As Arnold explained, "Keeping the GIS and hydraulic model synchronised is one of the biggest challenges, as we certainly want to avoid having to rebuild the water model from scratch every time the GIS is updated. The GIS-ID feature in WaterGEMS will be a big help in maintaining that relationship between the model and our up-to-date GIS. The software allow us to split a pipe or add a valve in the model without altering the relationship to the GIS. It makes updating the model a cleaner and easier process."