The Littleton/Englewood WWTP is located in the Upper South Platte River Basin. The effluent discharges into segment 14. This segment of the South Platte has been identified as a Reviewable Stream which requires an antidegradation review by the Division prior to issuing a permit to the L/E WWTP and other facilities. Antidegradation is defined in Colorado as: “These are waters designated by the Commission as having sufficient assimilative capacity to warrant application of measures to maintain current water quality and to allow reduction in current assimilative capacity only after public review processes justify the necessity of the reduction and that it is for accommodating important social and economic development”.
For purposes of adopting classifications and water quality standards, the streams and water bodies are identified according to river basin and specific water segments.
Within each river basin, specific water segments are defined, for which Use classifications and nume
ric water quality standards are adopted. These segments may constitute a specified stretch of river mainstem, a specific tributary, a specific lake or reservoir, or a generally defined grouping of waters within the basin (e.g., a specific mainstem segment and all tributaries flowing into that mainstem segment).
Segments are generally delineated according to the points at which the use or water quality characteristics of a watercourse are determined to change significantly enough to require a change in use classification and/or water quality standards. In many cases, such transition points can be specifically identified from available water quality data. In other cases, however, the delineation of segments is based upon best judgments of where in-
stream changes in uses or water quality occur, based upon upstream and downstream data.
Classifications of Uses
The Uses of segment 14 are classified as: Aquatic Life Warm 1, Agriculture, Recreation E, and Water Supply.