PERMFILE120715

• Permit No: C1981008A
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: NH1 TAB 17 PROBABLE HYDROLOGIC CONSEQUENCES
• Media Type: D
• Archive: Yes

•
seasonal water quality impact comparisons were made for Tuttle Draw only. The equation
used to compute existing and added chemical load is:
L=OxCx .0027
where:
L = The chemical load in tons/day
0 = Ground or surface water flow in cfs
C =The TDS concentration in mg/1
A second equation presented by Ferreira (1984) was used to calculate potential TDS
increases. The equation is:
DSC = DSL
OxF
where:
DSC = Resultant dissolved solids concentration in mg/7
DSL = The sum of the dissolved solid loads for the contaminant source and the

receiving source expressed as tons/day and calculated by the equation L = 0 x
C x .0027
0 = The sum of the contaminant and receiving medics flow rates expressed in
acre-feet/day
F = A constant factor, equal to 0.00136, for converting the product of acre-feet and
milligrams per liter into tons
•
Tables 17-16, 17-17, and 17-18 show the individual computations for same day (irrigation
season) impact analyses for mine discharges in Tuttle Draw, individual computations for
same day (non-irrigation season) impact analyses for mine discharges in Tuttle Draw, and
individual computations for impact analyses for mean annual mine discharges in Tuttle
Draw, respectively. Three important points can be made from the above-referenced
computations. First, water quality impacts to the San Miguel from Nucla Mine discharges ~
~~ ~ r
into Tuttle Draw are very minimal (1 percent). Second, impacts based on mean annual flows V~ ~ ~ ~/
L• Y..
are a worst case scenario. Lastly, the natural ground water discharge into the San Miguel ~uv u°
Su~O~
appears to have a significant degrading effect (29 percent increases in TDS) during the ,. ~
i rrf gati on season.
~-~ ('
~~' S
r
~`f~~
Having established that water quality impact assessments based on mean annual flow rates
17-64
Revised 04/11/88