Explanation
In the fall of 2013, the City of Columbus water supply from the Hoover Reservoir developed a taste and odor problem. The problem was derived from cyanobacteria (Anabaena) in the reservoir, which produced the compounds geosmin and 2-methylisoborneol (MIB). These compounds are known to cause taste and odor problems. During the months that the problem persisted, the City of Columbus spent an extra $723,000.00 on water treatment at their Hap Cremean Water Treatment Plant and was prepared to spend up to $970,000.00 in treatment in the fall and early winter of 2014-2015 as a preventative measure.
City of Columbus officials speculated that the 2013 taste and odor problem at Hoover Reservoir may have been exacerbated by nutrients absorbed by sediment or in decaying plant material that had settled to the bottom of the reservoir while it was stratified in the late-summer and early fall. Once the reservoir turned over in the fall, these nutrients were resuspended which contributed to the bloom of Anabaena in the fall and early winter.
The dam at Hoover Reservoir has three valves that the City can use to release water downstream: an upper valve, a middle valve and a lower valve. Prior to 2014, the City usually released water from the middle valve. However, during the summer-early fall stratification period of 2014, the releases were made from the lower valve. The rationale being that nutrients and sediment would be less likely to settle on the bottom of the reservoir during stratification if water was being released from the bottom; this was hoped to result in more nutrients being released downstream during stratification, meaning fewer nutrients would be available to promote cyanobacteria growth, which would result in less geosmin and MIB in the reservoir. The effectiveness of this practice is, however, largely unknown.
The objective of the proposed work is to do a synoptic survey of the physical and water-quality characteristics of the lower portion of Hoove...
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