The U.S. has over 84,000 reservoirs with a combined storage capacity that exceeds 600 million acre-feet of water. These reservoirs serve various purposes, including drinking water supply, recreation, irrigation, flood control, and hydropower. Some are exclusively for drinking water, some are recreational, and many are multi-use.
As public utilities, reservoirs are subject to more stringent management standards and must meet requirements for a range of water quality parameters that are not typically a concern for recreational water bodies. Those responsible include federal agencies (e.g., U.S. Army Corps of Engineers, Bureau of Reclamation), state governments, municipal water districts, and private organizations. Drinking water reservoirs often fall under the jurisdiction of local water utilities and health departments.
For these agencies, maintaining consistent water quality is essential for the effective operation of water treatment plants. Seasonal changes such as stratification of the water column can result in reductions in dissolved oxygen levels and increases in pH, levels of dissolved metals such as iron and manganese, taste and odor problems due to geosmins, total organic content, algae levels and in extreme cases, toxic cyanobacteria bloom events.
Algae outbreaks can release toxins like microcystins, which contaminate drinking water supplies. This contamination can cause water treatment disruptions, increased costs, and health risks like liver damage or gastrointestinal illness. Notable incidents include Toledo, Ohio’s 2014 crisis, where residents were unable to use their tap water for days.
With greater volatility in weather and climate, seasonal changes in water quality are becoming more frequent and pronounced. This leaves many treatment plant operators battling to respond and cope. Many are now actively seeking solutions that can minimize fluctuations in water quality consistency to reduce chemical costs, eliminate plant downtime for backwashing, and assist in meeting compliance standards for potable water.
Conventional approaches to addressing inconsistent water quality often involve the use of treatment chemicals and auxiliary treatment processes, which can increase plant operation costs and, in the case of chemical usage may generate potentially harmful byproducts. Chemicals can also lead to a detrimental cycle that accelerates the deterioration of the reservoir’s ecosystem.
“Fortunately, there are more effective natural, chemical-free processes that can be implemented to address the root causes of water quality degradation, not just the symptoms,” says Dave Shackleton, president of Clean-Flo International, a US-based leader in biological water management solutions for managing water quality,
“The focus should be on maintaining the reservoir’s balance of nutrients, organic matter, and dissolved oxygen, and promoting desirable aquatic organisms that help maintain a natural balance in the reservoir’s ecosystem that ensures nutrient clearance,” adds Shackleton.
To ensure a reservoir is suitable for public water supply, its quality must be consistent throughout the water column, and throughout the year, with a proper balance of nutrients and dissolved oxygen distributed evenly.
Sediment accumulation must also be addressed, which can become part of the permanent morphology of the lake. Simply physically removing and dumping sediment elsewhere through dredging techniques doesn’t allow the nutrients to be recycled within the lake ecosystem. Bioaugmentation, which involves the use of enzymes to break down organic muck, like a compost pile is a better solution.
Critical micronutrients can also be introduced to stimulate the growth of organisms that form the foundation of a productive food web.
The good news is that consistent use of these products over time reduces nutrient availability and helps maintain clean, healthy water.
For more information, visit www.clean-flo.com; email [email protected]; or call 1-800-328-6656.