REV93996

• Permit No: C1984062
• IBM Index Class Name: Revision
• Doc Date: 9/20/1990
• Doc Name: MR 90-11 COMMITMENT TO DEMONSTRATION MINE 3 PN C-84-062
• From: CYPRUS YAMPA VALLEY COAL CORP
• To: MLRD
• Type & Sequence: MR11
• Media Type: D
• Archive: No

David Berry
September 17, 1990
Page 2
comprises only 0.06% of that portion of the Trout Creek watershed;
combine this with the remaining body of the Trout Creek watershed
above station 69 and the parcel becomes minuscule in terms of
contribution to flow. As such, any impact which might originate
from the parcel in question would be insignificant when taken in
the context of the entire watershed, and could not be
differentiated from natural contribution/cycles over the watershed
under the current monitoring regime.
Secondly, any flow generated from the parcel would collect in the
Homestead Ditch, and from there infiltrate back into the soil. The
Homestead Ditch is of low enough grade and high enough permeability
to inhibit generation of ditch flow by all but the highest
intensity natural precipitation events or large irrigation flows.
As such, any contributions from the parcel would be retained on
site with the possible exception of those times when a high
intensity event occurred during a period of irrigation flow through
the ditch. It is CYCC's contention that during such times, the
quality and quantity of irrigation water passing through the parcel
would render any contribution from the parcel insignificant. This,
coupled with the infrequent nature of irrigation flows within the
ditch (none during the 1990 growing season) supports our contention
that the compilation and analysis of water quality data for
Stations 301 and 69 would not be useful or practical in regard to
the parcel in question.
MLRD CONCERN:
3. A detailed plan to monitor sediment concentrations on the
Homestead Ditch, including a baseline determination, and an
attempt to obtain similar measures during or shortly after a
precipitation event.
Response:
CYCC intends to temporarily monitor sediment concentrations during
irrigation in the following manner:
Baseline determination - Samples will be collected from the
homestead Ditch below the parcel in question, above the parcel,
and from a point immediately prior to where the ditch enters
reclamation. Samples will be analyzed for suspended sediments.
Demonstration - Following the establishment of a baseline
relationship, samples will be collected from the same points during
or immediately after a rainfall event for determination of sediment
yield from the parcel in question. Again, samples will be analyzed
for suspended sediments.