The Zürich, Switzerland water system provides residents with pristine filtered lake water. The water is pumped out of the lake, filtered, and stored in a ring of reservoirs around the city perimeter. The energy costs for pumping the water are staggering. The supply exceeds the demand by far: There are many unused reservoirs because the city uses less water now than anticipated when the reservoirs were built. Lyren is one of these underutilized reservoirs. Data and images are archived but not yet processed.