Vegetation and wetlands technical report : Union Pacific Resources Company, Greater Wamsutter Area II, natural gas development project

258 Pages·1995·52.2 MB·English

by  Grah, Oliver John

BLM LIBRARY
88072854
VEGETATION AND WETLANDS
TECHNICAL REPORT
Union Pacific Resources Company
Greater Wamsutter Area II
Natural Gas Development Project
ECOTONE
Environmental Consulting,
INC
123 EAST 200 NORTH, P.O. BOX 3516
LOGAN, UTAH 84321
BUS 801/752-2204 FAX [phone]
TD
195
. G3
D723
1995c

«m$h wn
VEGETATION AND WETLANDS
TECHNICAL REPORT
Union Pacific Resources Company
Greater Wamsutter Area II
Natural Gas Development Project
Prepared for
U.S. Department of the Interior
Bureau of Land Management
Rawlins District Office
Great Divide Resource Area
812 East Murray
Rawlins, Wyoming 82301-0670
and
Gary Holsan Environmental Planning
P.O. Box 175
Thayne, Wyoming 83127
Prepared by
Oliver John Grah
Juli Elayne Crane
ECOTONE Environmental Consulting, Inc.
P.O. Box 3516
Logan, Utah 84323-3516
December 1994
(Revised January 1995)

TABLE OF CONTENTS
Page
EXECUTIVE SUMMARY . iv
1.0 INTRODUCTION. 1
2.0 METHODS. 1
2.1 UPLAND VEGETATION. 4
2.2 WATERS OF THE U.S., INCLUDING WETLANDS AND OTHER
SPECIAL AQUATIC SITES. 5
2.3 PLANT SPECIES OF CONCERN, INCLUDING BLM SPECIAL
STATUS PLANTS. 6
2.4 CUMULATIVE IMPACTS. 7
3.0 AFFECTED ENVIRONMENT . 7
3.1 GENERAL VEGETATION. 7
3.1.1 Cover Types . 8
3.1.1.1 Mixed Desert Shrub. 8
3.1.1.2 Barren Land/Cushion Plant. 9
3.1.1.3 Urban Land. 9
3.1.1.4 Disturbed Land. 9
3.1.1.5 Wet Meadow . 10
3.1.1.6 Marsh . 10
3.1.1.7 Mudflat/Playa . 10
3.1.1.8 Aquatic Bed. 11
3.1.1.9 Open Water. 11
3.1.1.10 Riverine. 11
3.1.2 Weeds and Poisonous Plants. 12
3.1.2.1 Weeds . 12
3.1.2.2 Poisonous Plants . 12
3.2 WATERS OF THE U.S., INCLUDING WETLANDS AND OTHER
SPECIAL AQUATIC SITES. 14
3.2.1 Definitions . 14
3.2.2 Administrative Responsibility for and Regulation of Wetlands ... 15
3.2.3 Waters of the U.S. Cover Types. 16
3.2.4 Jurisdictional Areas Subject to the Clean Water Act. 16
3.2.4.1 Hydric Soils. 18
3.2.4.2 Wetland Hydrology . 18
3.2.4.3 Hydrophytic Vegetation. 19
3.2.5 Wetland Functional Values. 19
3.2.5.1 Groundwater Recharge . 20
3.2.5.2 Groundwater Discharge. 20
3.2.5.3 Flood Storage and Desynchronization . 21
3.2.5.4 Shoreline Anchoring and Dissipation of Erosive
Forces . 21
i

TABLE OF CONTENTS, Continued
Page
3.2.5.5 Sediment Trapping . 21
3.2.5.6 Nutrient Retention and Removal. 22
3.2.5.7 Food Chain Support. 22
3.2.5.8 Wildlife and Fish Habitat . 22
3.2.5.9 Heritage and Recreation Values. 23
3.3 EXTENT OF VEGETATION COVER TYPE COVERAGE . 23
3.4 PLANT SPECIES OF CONCERN, INCLUDING BLM SPECIAL
STATUS PLANTS . 24
3.4.1 Diffuse Sagebrush. 27
3.4.2 Broad-flowered Pincushion . 28
3.4.3 Cedar Rim Thistle. 28
3.4.4 Ownbey’s Thistle. 29
3.4.5 Wyoming Tansy Mustard . 29
3.4.6 Large-fruited Bladderpod . 29
3.4.7 Contracted Ricegrass. 30
3.4.8 Stemless Beardtongue. 31
3.4.9 Gibbens Penstemon. 31
3.4.10 Tiny Phacelia . 31
3.4.11 Opal Phlox . 32
3.4.12 Green River Greenthread . 32
3.4.13 Western Hop-sage. 33
4.0 ENVIRONMENTAL CONSEQUENCES. 33
4.1 INTRODUCTION. 33
4.2 IMPACT SIGNIFICANCE CRITERIA . 33
4.3 DIRECT AND INDIRECT IMPACTS. 34
4.3.1 Proposed Action. 34
4.3.2 Alternative A. 37
4.3.3 Alternative B. 38
4.3.4 Alternative C - No Action . 38
4.4 IMPACTS SUMMARY. 38
4.5 CUMULATIVE IMPACTS . 40
4.6 MITIGATION SUMMARY. 41
4.7 RESIDUAL IMPACTS. 43
5.0 REFERENCES CITED. 44
APPENDICES
Appendix A - Data Forms
APPENDIX A-l - Detailed Vegetation/Soils Sample Point Data Forms
APPENDIX A-2 - Wetland Sample Point Data Forms
ii

TABLE OF CONTENTS, Continued
Page
Appendix B - Species Lists
APPENDIX B-l - General Species List by Cover Type
APPENDIX B-2 - Species List and Wetlands Indicator Status
Appendix C - Personal and Written Communications
LIST OF EXHIBITS
Exhibit 1. Area Map - Location of the GWA II Analysis Area in South-Central
Wyoming. 2
Exhibit 2. Vicinity Map - Geographic Features within the GWA II Analysis
Area. 3
Exhibit 3. National Wetlands Inventory Map of the GWA II Analysis Area . 17
LIST OF TABLES
Table 1. Designated Noxious Weeds in Wyoming. 13
Table 2. Classification of Waters of the United States within the Analysis
Area. 18
Table 3. Estimated Functional Values for Wetlands and Riparian Areas within
the GWA II Analysis Area. 20
Table 4. Plant Species of Concern (including BLM Special Status Plants) and
Their Status and Habitat Characteristics. 25