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 Hydrogen sulfide threatens dams, water quality; As the weather warms and visitors flock to Atwood, Clendening and Tappan reservoirs, hydrogen sulfide gas – known for its rotten eggs smell – emitted from the dams downstream may seem like only a minor annoyance. But hydrogen sulfide gas is a hazardous substance to people and the environment, and threatens the structural integrity of the dams and nearby highway bridges. Hydrogen sulfide gas is produced by water runoff containing high concentrations of sulfate flowing into streams and later mixed with water in the bottoms of the reservoirs in the Muskingum River Watershed. The gas and smell is most common in the warmer months of summer and early fall. Recently, warnings from the federal government about possible health effects and a temporary restriction of public access to certain areas around Atwood, Clendening and Tappan dams were issued. According to the U.S. Army Corps of Engineers (USACE), which operates the dams, conditions presently exist for the presence and possible release of hydrogen sulfide gas at the points where water is released from the dams to downstream areas at Atwood, Clendening and Tappan dams. Officials emphasized the reservoir areas behind the dams do not pose a danger to visitors and remain safe for boating, fishing and swimming, since the problem occurs when the water is released from the dams. Hydrogen sulfide is a colorless gas that easily can be recognized by its strong odor, but symptoms of exposure to high levels of the gas include fatigue, dizziness, nausea, eye irritation and headaches. Young children are at particular risk. Members of the Board of Directors of the Muskingum Watershed Conservancy District (MWCD), which manages the reservoirs in the watershed for flood reduction and water conservation with the USACE, heard a report about hydrogen sulfide during a recent meeting. Scott Tritt, MWCD safety coordinator, told Board members that the production of hydrogen sulfide gas is a naturally occurring process as a result of decaying organic material in the reservoir (lake). As the water passes from the reservoir through the dam, the hydrogen sulfide gas is released into the air. “It is a potential health problem and repairs that have been proposed for the dams will help in a remedy for it,” Tritt said, noting that federal health experts recommend exposure times for hydrogen sulfide of only 10 minutes in an eight-hour period when concentration levels are high. The USACE also notes that the presence of certain levels of hydrogen sulfide gas can cause hazards for the fish and other aquatic life downstream from the dams, and create an environment that leads to the early deterioration of concrete at the dams. USACE officials have closed the areas immediately adjacent to the downstream release points of the dams at Atwood, Clendening and Tappan dams until the hydrogen sulfide levels return to normal, probably sometime this fall. The USACE also pledged that it will continue to monitor the areas and will notify the appropriate agencies and the public if the concentration levels are determined to pose a threat to public safety. However, in the long term, the release of hydrogen sulfide gas can be reduced through improvements to five dams proposed by the USACE. The cost of the work at Atwood, Clendening, Leesville, Piedmont and Tappan dams would be about $3 million each or a total of $15 million. The work would require the participation of a local sponsor to share in the total cost of the projects. The MWCD has agreed to serve as the local cost-share sponsor, providing 25 percent of the overall costs, or an estimated $3.75 million. The MWCD would pay for its share of the estimated costs for the five dams from the funds it will collect from a proposed assessment of property owners for maintenance of the system of reservoirs and dams in the 18-county MWCD region. An exact schedule for the work has not been finalized by the USACE. “The work to be completed to reduce the release of hydrogen sulfide gas at these five projects is a matter of public health and safety,” said John M. Hoopingarner, MWCD executive director/secretary. “This project is another opportunity for the conservancy district to participate with a small percentage of the cost to leverage a very large investment in the maintenance of the system of dams and reservoirs for the safety of our children and grandchildren for generations to come.” The MWCD is a political subdivision of the state organized in 1933 to develop and implement a plan for flood reduction and water conservation in the Muskingum River Watershed. By 1938, 14 reservoirs and dams were constructed. According to the MWCD’s maintenance and assessment plan, an estimated $10.5 million annually would be generated from property owners in the MWCD region for projects to safeguard the system of reservoirs and dams originally constructed in the 1930s. In a study of the watershed, national, state and local experts and agencies identified about $270 million worth of needed projects in the system that are the responsibility of the MWCD. The MWCD reports that the assessment and projects, including partnering programs with the federal government and other agencies and participants, will begin as early as 2008. The MWCD has projected that 94 percent of the estimated 500,000 parcels subject to the assessment would pay an annual fee of $12 per year. Projected assessments can be reviewed online at the MWCD website at www.mwcd.org, and the MWCD also can be contacted toll-free at (877) 363-8500. Because of its relationship with the USACE and the income derived primarily from the recreational use and natural resources stewardship of its lands and waters, the MWCD has not experienced the need to levy an assessment over the past 70 years. However, the rising costs associated with safety upgrades and maintenance in the system of reservoirs and dams are much more than the MWCD routinely can generate from its traditional revenue sources. The counties wholly or partially contained in the MWCD jurisdiction are Ashland, Belmont, Carroll, Coshocton, Guernsey, Harrison, Holmes, Knox, Licking, Morgan, Muskingum, Noble, Richland, Stark, Summit, Tuscarawas, Washington and Wayne.
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