WSP01414

• File Number: 8449.918
• Description: South Platte Projects
• State: CO
• Basin: South Platte
• Date: 8/1/1982
• Author: CWCB
• Title: South Platte River Basin Assessment Report
• Water Supply Pro - Doc Type: Publication

coli forms and copper concentrations in Clear Creek are considered to impair

water quality from the standpoint of potential drinking water use. Other

concerns about the water quality conditions of Clear Creek include large

sediment loads, large concentrations of trace metals, and nutrients. These

water quality concerns in this sub-basin possibly are aggrevated by

channelization, placer mining, and discharges from 14 wastewater treatment

facilities into Clear Creek (Colorado Department of Health, 1980).

The upstream reaches of St. Vrain Creek contain small concentrations of

dissolved solids, usually less than 400 mg/l. Downstream from Longmont,

effects of municipal wastewater discharges and agricultural return flows

are primary water quality concerns in this sub-basin. The saline

characteristics of the shale soils located within the foothills of the

St. Vrain Creek, Cache 1a Poudre River and Big Thompson River sub-basins

also contribute to increased dissolved solids concentrations within the

stream segments of the Plains zone (Larimer-Weld Regional Council of

Governments and Toups Corporation, 1978).

Water quality in the upper Big Thompson River near Estes Park is

characterized by small dissolved solids concentrations, usually less than

100 mg/l (Engineering Consultants, Inc. and Toups Corporation, 1974).

Dissolved solids concentrations remain quite small until the river flows

through the Big Thompson Canyon, where much of the streamflow of the Big

Thompson River is diverted for irrigation use by several ditches.

Downstream from the canyon, municipal wastewater discharges from the city

of Loveland affect levels of dissolved oxygen and fecal coliform and

contribute partially to the impaired stream water quality. The Big

Thompson River from Loveland downstream to its confluence with the South

Platte River is affected by irrigation return flows and their associated

dissolved solids loadings (Colorado Department of Health, 1980).

In its upper reaches, the Cache la Poudre River contains small concentra-

tions of dissolved solids, usually less than 100 mg/l (Engineering

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