Heavy rainstorms two years ago created a large puddle of water in the usually dry Salt River bed east of Tempe Town Lake in Tempe, Ariz. The puddle is still in place today.
According to the ASU Web Devil, the puddle is creating water quality problems in the lake, and Tempe officials are now spending $2.5 million to pump the excess water around Tempe Town Lake.
Basil Boyd, a Tempe water resources hydrologist, reported that the high-algae water flows into Town Lake at the east end, forcing the lake's algae-treated water out from the west end.
High algae raises the pH level in water to the point that swimming is unsafe.
Officials treat Tempe Town Lake water to keep the pH level at or below the regulatory limit of 9.0, but the constant water flow replaces some of the lake's treated water with water that is at 9.6 pH level.
A pH above 9.0 can cause health problems, including eye irritation and bacterial infections.
Two swimming events have been affected by the high pH levels. One event was cancelled, while the other was moved to an Arizona State University pool.
When the lake's infrastructure was constructed, officials underestimated the amount of water that would need to be pumped.
The new construction project will enlarge a half-mile portion of an existing pipe, which will allow a pumping capacity of 15 to 20 million gallons per day.
The ASU Web Devilreports that the city will rent pumps to push the water into the pipeline, which will then be sent into a storm drain that empties into the Salt River bed west of the lake.