WSP04249

• File Number: 8443
• Description: Narrows Unit
• State: CO
• Basin: South Platte
• Water Division: 1
• Date: 5/9/1977
• Title: Analysis of a Ground-Water Recharge System Alternative
• Water Supply Pro - Doc Type: Report/Study

GOGJ

The greatest source of pollutants in the basin was identified as being

croplands. To date no recommendations for control have been forthcoming,

---.
.
~.1
. ,

although this source was given a high priority. It was concluded that

croplands would remain a significant source of nutrients. It was

further concluded that nutrient levels in the river would remain high

in the future and would unlikely be the limiting factor to primary

-

production or algal biomass.

,
i
.-1

Numerous other factors were considered in predicting what would occur;

mainly these concerned the reservoir itself and its operation. The

-..=.

conclusion reached was that, while the reservoir could probably be

classified as being eutrophic on the basis of nutrient levels, primary

-

productivity or algal standing crop, problems associated with

eutrophication, e.g. oxygen depletion, would not occur. On the basis

of the above factors, nearly all plains reservoirs have been or could

-

be classified as eutrophic. However, the adverse side effects of

eutrophication are rarely encountered. Narrows Reservoir was concluded

to De rather typical of plains reservoirs in the region.

'\.

I':
~

:~

.'

Eutrophication would undoubtedly degrade the aesthetics of the

;1
.,

reservoir and thus the quality of the recreation;'experience. However,

.\

. ~.

excessive algal growth, should it occur, is not of itself inimical to

recreational use. As a matter of fact, during the EIS process, the

,
,
(

major concern expressed relative to the effects of eutrophication on

-

recreational use did not involve excessive algal growth, but rather

7

,
!r-
!:
i:
,.
j;
,
.1.

the potential for excessive growth of rooted aquatic plants, which