BOARD00284

• Board Meeting Date: 1/12/1971
• Description: Agenda or Table of Contents, Minutes, Memos
• Board Meetings - Doc Type: Meeting

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5. The biological results showed no
evidence of an algal 'bloom' during this survey.
On the basis of dissolved oxygen and nutrient
concentrations, depth of the euphotic zone, and
plankton populations, none of the three lakes
could be considered eutrophic. The productiv-
ity of Granby and Grand Lakes is such that
their classifications are between oliogotrophic
and mesotrophic. Shadow Mountain Lake was the
most productive and could be classed as a meso-
trophic lake.

6. The existing water quality of the
three lakes is equal to or better than the
standards established for the classified uses
of the three lakes except that the dissolved
oxygen concentrations in the hypolimnion of
Lake Granby were less than the established
standards of 6.0 mg/l. It is possible that
natural sources of organic material are the
major cause of the depressed dissolved oxygen.
The limited scope and duration of the study
however did not permit a complete evaluation
of this situation, and further study is indi-
cated to provide a basis for remedial action.

In order to protect and/or enhance water
quality and water uses of Grand Lake, Shadow
Mountain Lake, and Lake Granby, it is recom-
mended:

I. That the classification B3' Body
Contact Recreation, be added to the water uses
established for the three lakes.

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2. That the Colorado Water Pollution Con-
trol Commission establish water quality
standards for the three lakes and their tribu-
taries containing nutrient criteria and required
waste treatment and other control measures which
will not only prevent further enrichment of these
waters but enhance their quality.

3. That immediate action be taken to con-
trol and treat all wastewaters in the three