The South Platte River meets many needs in the Denver area. It supports aquatic, benthic, and riparian ecosystems throughout the region. The aquatic life use is a regulated use of the stream and, in many cases, results in the most stringent effluent discharge limitations at the plant.
As a major water feature in the area, many recreational activities occur on the river and its banks. These activities include water contact sports, such as boating and kayaking, some swimming, fishing, and panning for gold. The river corridor supports an extensive urban trail and park system used for walking, biking, jogging, skating, picnicking and general enjoyment by the public. The river is also a source of drinking water for downstream communities.
The water is reused several times as it flows through the Platte River system to the Missouri and Mississippi Rivers. The drinking water use is the basis for the many of the most stringent limitations on nitrates and organic compounds.
Agricultural uses of the river can dictate the river flow, particularly in the irrigation season. These senior water users ‘call’ water during the drier portions of the year when crops need the moisture. A set of water quality criteria exists for each of the designated beneficial uses: ·recreational class I ·aquatic life, warm water class I ·domestic water supply· and agricultural use.
The wastewater flows from several POTWs make up a large part of the river flow most of the year. At the river location just upstream of the Littleton/Englewood WWTP, plant effluent actually exceeds normal river flow during certain times of the year. In this situation, wastewater effluent, storm water runoff, and irrigation return flows have a major impact on river water quality. The plant operates under the conditions of a discharge permit issued by the Colorado Department of Public Health and Environment. The permit contains requirements on all phases of plant operations and effluent limitations that must be achieved.