PERMFILE121332

• Permit No: M2001046
• IBM Index Class Name: Permit File
• Doc Date: 5/9/2002
• Doc Name: Proposed Wetland Monitoring Plan
• From: Banks & Gesso
• To: DMG
• Media Type: D
• Archive: No

MAY-69-2002 TNU 09;59 AM BANKS AND GESSO LLC
MRY 09 2002 ~~38 FR WRIGHT WRTER
DRAFT- Momormtdum to Zhg 141ettin
May 8, 2002
Page 2
FAX N0. 303 274 8329
X34801020 TO X32748329
P. 03
P.03i06
conditions, iacludmg potential exiatiog iatpaCts from the Vaax operation north of the proposed Nix
Pit. It is anticipated that mo~nitoting wells MW-24 and MW-25 w[71 be need to assess bothpie-and
post-mining effects in du vicinity of tba Sago HiU Fatm wetland. A1125 piezome[era ehonld be
lead es folkvus:
• May through midiuly~-biweekly
• Mid-July through October--montlily
It is rccCmmcnded that the Last t;hattco and Side Hill ditches be observed when the piezontetere are
read to determine if ere Avwitrg. Relative water 1eve1 observations should also be made
of the east anti north of the wetland, respectively. TJris information eau assist
with dal the effects of irrigation art gtundwater levels.
Proposed Worland Mitisatloa 1ti~er
It is important that any trigger for wetland mitigation measures be able to distinguish e8'eds Cm the
groundwater cable duo to the Nrx operation from eilbcts dun to othor factors. Other faCtars include:
tiro conditions, changes is ditch diversions, pumping from high volwne irrigation wells (eg.,
th i well northeast of MWjI), and the Varra pit. AU of these other faotors could result in a
groundwater table apart from this Nrx Pit. Thucfors, it is rocommmfded that nay trigger
assess wbetbor;
1) A drop in the grosmdwater table goer the Nix Pit is due m the pit itself and not other factors,
2) The drop is affnating or could affect the wetland an the Saga IiiII Farm.
It is not possible at this titan to de5ae apeCific, numeric limits for the trigger because of the lack of
data to determine pratnining groundwater conditions and the apparent variabiUty fn groundwater
levels. The hyttrologic regime of the wetland requires further momtoriag and evaluation.
Therefore, the Following desCn'bea the recammeaded approach to wller;t additional data to do5ue
specific nigger limits in the filntre.
h is recommeruicd that the fast component be assessed by eomparlrtg readiaea from new
piezometcr MW ZS that is tmaffrcted by the Nix Pit and indicative of tits regional groundwater
table with roadings from MW 3 that will show the effects of the operation. These two piecometers
will bo xssd this atnmrter and s cosrelation established between readings. Future meaeiuemertta that
deviate from this correlation will indicate an impact on the gtvupdwater table Tram rho Nu Pit. It ie
anticipated that the gelation 6etweea the wells and rho basis for a deviation wIIl be established at
the end of this summer.
h is receaimrnded that the second conrpopoat of the trigger be evalual>:d by Competing readings in
MW-6 and MW- 24 (a raw piemmeter located is the middle of rho wetland) with `tpre-milting
Conditions" established e8er another fl11! glowing season of monitoring. if groundwater levels fall