June 12, 1998

Contact: Geoffrey Ryan, NYCDEP (718/595-5371)

City to Install Aerators at New Croton Reservoir

Commissioner Joel A. Miele Sr., P.E., of the New York City Department of Environmental Protection (DEP) announced today that, on Tuesday, June 16th, the Department will start installing three hypolimnetic aerators in the New Croton Reservoir as part of an 18-month pilot program. Two aerators will be placed near the Croton Lake Gate House, the third will be east of the Old Croton Reservoir Dam, which is now submerged. The aerators will increase oxygen levels in the water, which are depleted at the New Croton Reservoir during warm weather months. It is expected that increased oxygen levels will reduce releases from sediments of iron and manganese which cause color to appear in water in the distribution system. Additionally, the lack of dissolved oxygen increases the release of phosphorus from sediments. Phosphorus is a nutrient which encourages the growth of algae. The algae may contribute some odor to water and cause depletion of oxygen in the water.

"The results of this pilot study will help us determine if full-reservoir aeration will benefit overall water quality," said Commissioner Miele. "If we go ahead with full-reservoir aeration, the study will provide us with information for the proper sizing and placement of additional aerators for optimal performance."

"Installation will require a boat on the water for a few days, and a crane will be on-site initially," Commissioner Miele continued. "I want to assure residents in the area that their views will not be disturbed by the pilot project. The aerators will be submerged and not visible from the shore, and the pilot project requires no new structures, no new roads, no stream disturbances, and no dredging or filling. An additional benefit may be that anglers will find more fish in the areas receiving increased oxygen supplies."