REP23089

• Permit No: C1980007
• IBM Index Class Name: Report
• Doc Date: 12/11/2001
• Doc Name: 1986 AHR text
• Annual Report Year: 1986
• Permit Index Doc Type: Hydrology Report
• Media Type: D
• Archive: No

2.3.2 Ca~arison_of Baseline Water Quality with Operational Data
Of the ten parameters selected for baseline characterization, seasonal trends
l are apparent for TI.15, TSS, and total iron. The other parameters do not exhibit
1 seasonal variation. Total dissolved solids are least concentrated in the North
Fork during the period between about May and July, probably because high~l'AS
ground water is diluted by snow runoff. Total iron is most concentrated during
this period of time. Total suspended solids aze Brost concentrated from April to
July.
A oatg~arison of baseline water quality data in the North Fork of the Gunnison
River to 1986 monitoring data shows no significant changes in water quality in
the North Fork. Slightly higher results can be related to higher than previous
fall precipitation and are not a result of mining. There does not appear to be
J any changes in the North Fork of the Gunnison River quality that can be
attributed to affects of mining for water yeaz 1986.
2.3.3 Mine Water Management and I~ct Assessment
The discussion of the mine water system
organized by the four sources of water:
1) North Fork water
2) sanitary wastewater
3) mine water, and
4) runoff from disturbed areas.
and hydrologic impact assessment is
Use and discharge of water from these sources is studied for its potential to
affect the North Fork.
North Fork Water
During Water Year 1982 the conditional right to withdraw water flan the
North Fork was deemed absolute. When this water right is in priority,.
water can be pumped from the intake point to the freshwater storage pond(s)
within the surface facilities azea. In average years, this water right is
expected to be out of priority from July to September, but in 1977 it would
have been out of priority from April to September. In water yeaz 1986
WDCx's Mt. Gunnison Pipeline water right met quadrennial diligence for the
conditional portion and an additional portion was deemed absolute by the
Division 4 water court bringing the absolute portion to 0.88 cfs. ~2 uC{-{~~~,~~
The 10-acre-foot capacity pond provides for water storage during the term
of permit; twv ponds ace anticipated for subsequent permit terms. Water
can also be stored in Sediment Ponds MB-1, MB-2, and MB-3, under a separate
decree. Storage is _us_ually- -limited. _. to-the -marimum__sediment . level
elevation. Transfer to FW-1 is possible as outlined in the M & R Plan.
Average' withdrawals are not expected to exceed 50,000 gpd during the term
of permit and are likely to be on the order of 45,000 gpd, depending on
production levels and requirements. During 1986 average withdrawal was
45,900 gpd for 250 working days.
Water from the freshwater pond(s) is either treated to meet potable and
sanitary water requirements, used and then treated as sanitary waste water,
or it is withdrawn for dust suppression in the mine is which case it then
beoornes mine water. WECC's Mt. Gunnison Pipeline water rights were not out
of priority during water year 1986, probable due to above average fla,rs and
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