2011-10-25_REVISION - M1977300

• Permit No: M1977300
• IBM Index Class Name: REVISION
• Doc Date: 10/25/2011
• Doc Name: Review
• From: IRIS Mitigation and Design, Inc.
• To: U.S. Fish and Wildlife Service
• Type & Sequence: TR18
• Email Name: DB2
• Media Type: D
• Archive: No

IRIS
MITIGATION AND DESIGN, INC.
Environmental Consulting
IRIS MITIGATION AND DESIGN, INC.
3450 W. 32 Avenue, 2nd Floor
Denver, Colorado 80211
Phone: 720 - 272 -1985
[e-mail]
Please note that the impact areas in Table 1 have changed from the originally calculated areas in
the Biological Assessment as totaled on Table 10 and as depicted on Figures 8 to 10 of the
Biological Assessment. Figure 8 has been re -drawn and areas recalculated due to the following
design changes just up and downstream of the cutoff wall (see enclosed updated Figure 8):
• Originally proposed riprap along riparian areas and within upland areas is now proposed to
be buried below 6" of topsoil which will be seeded/mulched and revegetated. Some previous
permanent riparian and upland impact (unburied riprap) has therefore become temporary
impact (buried riprap).
• Riprap areas on uplands near the existing road have been further minimized and/or buried
creating less permanent upland area impact.
We are also now proposing to mitigate for 0.09 acre of temporary riparian impact partially at the
end of Phase 1 construction by restoring approximately 4,000 ft of riparian area upstream of the
proposed cutoff wall in the area that was previously undisturbed riparian habitat (pink area on
Figure 8). The 0.09 acre area will be seeded /mulched/blanketed with a combination
wetland/transitional area native seed mix and will be further restored through planting willow
stakes 2 feet on center throughout the 4,000 ft area (1,000 willow stakes total). This area will be
planted with 40 riparian trees (species shown on Table 2) approximately 10 feet on center at the
end of Phase 2 construction activities. We are waiting to plant the riparian trees in the event that
some of this area is further impacted during Phase 2 construction.
The shrubs in Mitigation Area 1 (0.13 acre total) were calculated in two portions of the
mitigation area: 150 upland shrubs in the 0.09 acre upland area and 70 riparian shrubs in the 0.04
acre riparian area. Calculations show this total to be 220 shrubs in a 0.13 acre area. With
clumps planted 10 feet on center this totals just under 4 shrubs per clump (you had calculated 2.6
shrubs per clump in your review). Please let me know if there is an issue with my calculations
otherwise we will leave the number of shrubs in Mitigation Area 1 as is.
The upland areas that will be impacted have few trees and shrubs since the upland areas include
mainly waste rock piles. These waste rock piles are capped and vegetated with upland grasses
only. However there are several ponderosa pines and a few junipers that may be impacted
during Phase 1 construction (approximately 10 trees). Of these 10 trees, 2 have dbh greater than
15 ", 4 have dbh 6 " -15 ", and 4 have dbh less than 6 ". If impacted, 18 upland trees (14 ponderosa
pine and 4 junipers) will be planted/mulched in the restored upland area once it has been
seeded/mulched. There are approximately 86 upland shrubs that may be impacted within the
proposed upland impact area. If impacted 120 upland shrubs will be planted/mulched from the
upland shrub list as detailed in Table 6 of the Biological Assessment. Therefore the upland area
restoration includes up to 18 ponderosa pines /junipers and 120 upland shrubs planted during
Phase 1 upland restoration.
Schwartzwalder Mine Phase 1 Page 5 October 2011
Response to USFWS Comments