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

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Water Quality

The mainstem South Platte River and its major tributaries exhibit wide

spatial variations in water quality characteristics. Selected water

quality data tabulations and graphic stream reach profiles for the mainstem

South Platte River and its major tributaries were included in a statewide

water quality study by Gaydos (1980). A summary of stream quality for the

South Platte River basin (Figure 9 and Table 11) indicates that average

concentrations of dissolved solids and major ions generally tend to

increase in a downstream direction in the mainstem South Platte River from

Henderson to Julesburg (Figure 9). This general pattern of increased

concentrations in a downstream direction in the basin is felt to be a

combined effect of water reuse, increased use for irrigated agriculture,

and percolation of return flows through sedimentary soils. Increased

average concentrations of major ions represent a decrease in quality of

water which may impact adversely its irrigation and domestic uses. Water

quality sampling locations used for purposes of this analysis are shown on

Figure 1. Increased sulfate concentrations were noted in the downstream

location of the South Platte River as well as in its major tributaries

(Gaydos, 1980).

The Colorado Department of Health (1981) recently adopted standards for the

four river basins in the northeastern part of the state. These standards

classify waters into high quality, recreation, aquatic life, water supply

and agriculture. High quality Class I or Class II waters are a special

classification reserved for waters that represent an outstanding state and

national resource. other classifications (recreation, aquatic life, water

supply and agriculture) pertain to the specific water use. High quality

Class I waters in the South Platte River basin are limited to all

tributaries of the Cache la Poudre River within Rocky Mountain National

Park. High quality Class II waters include all tributaries to the Big

Thompson River and St. Vrain Creek within the boundaries of Rocky Mountain

National Park, all tributaries to St. Vrain Creek and to Boulder Creek

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