Surface and Well Water Blending Study

Public Outreach Event Features Blind Tasting of Well and Surface Water Blends

Bennett Engineering Services was retained to prepare an engineering study to determine options available to the Department of Environmental Utilities for blending aquifer storage and recovery (ASR) well water with surface water. The department had received complaints from some customers when the well water completely replaced groundwater.

As a part of the study, the team adapted the city’s H2OMAP water model to provide data on mixing percentages. The Roseville water model was not configured to show mixing, so the analysis method was revised. In addition, solutions requiring new piping were compared to solutions requiring existing pipe isolation. In order to be certain that fire flows were not degraded, fire flow analyses were also run for the existing pipe options.

Multiple, extended-period simulations were used to determine the effectiveness of mixing under various plumbing scenarios over one day to one week durations, by observing the model-predicted blending percentages from each source at critical nodes. A final report was prepared that provided the mixing results of more than thirty blending and plumbing scenarios.

The team then conducted a community outreach event where the public was invited to blind test and score various blends of well and surface water.