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BUREAU OF LAND MANAGEMENT RIPARIAN AREA MANAGEMENT Proper Functioning Condition Assessment for Lentic Areas Technical Reference 1737-16, Third Edition, 2020 Suggested citations: Gonzalez, M.A. and S.J. Smith. 2020. Riparian area management: Proper functioning condition assessment for lentic areas. 3rd ed. Technical Reference 1737-16. U.S. Department of the Interior, Bureau of Land Management, National Operations Center, Denver, Colorado. U.S. Department of the Interior. 2020. Riparian area management: Proper functioning condition assessment for lentic areas. 3rd ed. Technical Reference 1737-16. Bureau of Land Management, National Operations Center, Denver, Colorado. Production services provided by: Information and Publishing Services Bureau of Land Management National Operations Center P.O. Box 25047 Denver, CO 80225-0047 Printed copies available from: Printed Materials Distribution Service Fax: 303-236-0845 Email: [email protected] Also available online at: http://www.blm.gov/wo/st/en/info/blm-library/publications/blm_publications/ tech_refs.html BLM/OC/ST-20/003+1737 RIPARIAN AREA MANAGEMENT Proper Functioning Condition Assessment for Lentic Areas Mark A. Gonzalez Steven J. Smith Riparian/Wetland Ecologist (Soils) Riparian Ecologist National Riparian Service Team Team Leader of the National Riparian Service Team Bureau of Land Management Bureau of Land Management Prineville, Oregon Prineville, Oregon With contributions from the original working group of the first edition of Proper Functioning Condition Assessment for Lentic Areas, Technical Reference 1737-16: Don Prichard, Fishery Biologist, National Steve Leonard, Riparian Ecologist/ Operations Center, Bureau of Land Grazing Management Specialist, National Management Riparian Service Team, Bureau of Land Management Forrest Berg, Stream Mechanics Engineer, Natural Resources Conservation Mary Manning, Ecologist, Forest Service Service Chris Noble, Soil Scientist, Riparian/ Warren Hagenbuck, Regional Wetland Wetland Technical Team, Natural Coordinator, Fish and Wildlife Service Resources Conservation Service (retired) Janice Staats, Hydrologist, National Russ Krapf, Soil Scientist, National Riparian Service Team, Forest Service Training Center, Bureau of Land Management Robert Leinard, Plant Ecologist, Riparian/Wetland Technical Team, Natural Resources Conservation Service And contributions from the working group of the second edition of Proper Functioning Condition Assessment for Lotic Areas, Technical Reference 1737-15: Melissa Dickard, Aquatic Ecologist, Steve Leonard, Riparian Ecologist, National Operations Center, Bureau of National Riparian Service Team, Bureau of Land Management Land Management (retired) Wayne Elmore, Riparian Ecologist, Dave Smith, Wildlife Biologist, Fish and National Riparian Service Team, Bureau of Wildlife Service Land Management (retired) Steve Smith, Riparian Ecologist, National Mark Gonzalez, Riparian/Wetland Riparian Service Team, Bureau of Land Ecologist (Soils), National Riparian Service Management Team, Bureau of Land Management i Janice Staats, Hydrologist, National Dave Weixelman, Riparian Ecologist, Riparian Service Team, Forest Service Forest Service (retired) Sandra Wyman, Rangeland Paul Summers, Groundwater Management Specialist, National Hydrologist, National Operations Center, Riparian Service Team, Bureau of Land Bureau of Land Management Management Technical Reference 1737-16 Third Edition ii Acknowledgments This document was improved by the thoughtful and valuable input, discussion, and reviews of the following contributors: Alan Bass, Rangeland Management Specialist, Bureau of Land Management Tim Burton, Hydrologist and Fisheries Biologist, Forest Service and Bureau of Land Management (retired) Samuel Cox, Natural Resource Specialist/Cartographer, Bureau of Land Management Kate Crane, Fisheries Biologist, Bureau of Land Management Melissa Dickard, Ecologist, Bureau of Land Management Dennis Doncaster, Hydrologist, Bureau of Land Management Jimmy Eisner, Fisheries Biologist, Bureau of Land Management Wayne Elmore, Riparian Ecologist and Wildlife Biologist, Bureau of Land Management (retired) Patrick Farris, Rangeland Management Specialist, Bureau of Land Management Gene Fults, Rangeland Management Specialist, Natural Resources Conservation Service, West National Technology Support Center Amanda Gearhart, Wild Horse and Burro Specialist, Bureau of Land Management Joseph Gurrieri, Hydrologist, Forest Service David Hopkins, Soil Scientist, North Dakota State University Justin Jimenez, Aquatic Habitat Management Program Lead, Bureau of Land Management Jamin Johanson, Ecologist, Natural Resources Conservation Service Jon Kaminsky, Geologist, Bureau of Land Management Lucy Littlejohn, Fisheries Biologist, Bureau of Land Management (retired) Valda Lockie, Ecologist, Bureau of Land Management Scott Lusk, Rangeland Management Specialist, Forest Service Mary Manning, Ecologist, Forest Service Lorraine Manz, Geologist, North Dakota Geological Survey Acknowledgments iii Scott Maclean, Fisheries Biologist, Bureau of Land Management John McCann, Hydrologist, Forest Service Cassie Mellon, Aquatic Ecologist/Fisheries Biologist, Bureau of Land Management Diane Menuz, Wetland Program Coordinator, Utah Geological Survey Stephanie Miller, National Riparian Program Lead, Bureau of Land Management Brenda Mitchell, Hydrologist, Forest Service Alen Mosley, Fisheries Biologist, Bureau of Land Management Sarah Peterson, Lead, Soils and Aquatic Habitat Management Programs, Bureau of Land Management Thomas Probert, Hydrologist, Bureau of Land Management Peggy Redick, Ecologist/Monitoring Coordinator, Bureau of Land Management Christopher Reidy, Wetlands Planner/Ecologist, Natural Resources Conservation Service, West National Technology Support Center Lindsay Reynolds, Riparian Ecologist, Bureau of Land Management Lindsey Rush, Wildlife Biologist, Bureau of Land Management Liz Schnackenberg, Hydrologist, Forest Service Samantha Seabrook-Sturgis, Botanist, Bureau of Land Management Alden Shallcross, Hydrologist and Lead, Aquatic Habitat Management Program, Bureau of Land Management Anna Smith, Hydrologist, Bureau of Land Management Joshua Sorlie, Soil Scientist, Bureau of Land Management Janice Staats, Hydrologist, Forest Service (retired) Sherm Swanson, Ecologist, University of Nevada-Reno (retired) Lenore Vasilas, Soil Scientist, Natural Resources Conservation Service David Weixelman, Ecologist, Forest Service (retired) Sandra Wyman, Rangeland Management Specialist, Bureau of Land Management (retired) The authors extend a special thank you to Nancy Esworthy, Writer/Editor, and Jennifer Kapus, Visual Information Specialist, BLM National Operations Center, for their outstanding effort to review, edit, format, and polish the text, figures, and tables of our original manuscript. Nevertheless, the authors take sole ownership of any errors that may have inadvertently passed through the editorial process. We appreciate Nancy and Jennifer’s great attention to detail and their gift for writing, drafting, and editing. iv Acknowledgments Abbreviations BLM – Bureau of Land Management DMA – designated monitoring area EC – electrical conductivity ESP – exchangeable sodium percentage FAC – (see WIC) FACU – (see WIC) FACW – (see WIC) FAR – functional–at risk GIS – geographic information system GPS – global positioning system HGM – hydrogeomorphic ID – interdisciplinary IRMP – integrated riparian management process LIDAR – light detection and ranging (data) MIM – multiple indicator monitoring NA – not applicable NF – nonfunctional NRCS – Natural Resources Conservation Service NWI – National Wetlands Inventory NWI+ – National Wetlands Inventory Plus NWIPlus – National Wetlands Inventory Plus OBL – (see WIC) PFC – proper functioning condition PNC – potential natural condition TR – technical reference UAV – unmanned aerial vehicle UPL – (see WIC) USGS – U.S. Geological Survey WIC – wetland indicator category (arranged wettest to driest) OBL – obligate FACW – facultative wetland FAC – facultative FACU – facultative upland UPL – upland Abbreviations v Contents Acknowledgments ................................................................iii Abbreviations..................................................................... v 1. Introduction................................................................... 1 Purpose of This Technical Reference and Changes from Earlier Editions . . . . . . . . . . . 3 Intended Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Managing Riparian-Wetland Areas Using an Integrated Process.............. 7 Step 1: Assess Riparian-Wetland Area Function Using the PFC Method . . . . . . . . . . . 8 Step 2: Identify Riparian-Wetland Resource Values and Complete Additional Assessments..................................................... 8 Step 3: Prioritize Sites for Management, Restoration, or Monitoring Actions . . . . . . 9 Step 4: Identify Issues and Establish Goals and Objectives . . . . . . . . . . . . . . . . . . . . . .10 Step 5: Design and Implement Management and Restoration Actions...........11 Step 6: Monitor and Analyze the Effectiveness of Actions and Update Resource Condition Ratings (PFC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 Step 7: Implement Adaptive Actions...........................................13 3. Preparing for a PFC Assessment..............................................14 Identify the Assessment Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 Assemble an Interdisciplinary Team . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 Gather and Review Existing Information........................................15 Delineate and Stratify Assessment Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 Plan and Time the Assessment Approach.......................................25 4. Conducting a PFC Assessment ...............................................27 Determine the Potential of the Assessment Area................................27 Assess the Riparian-Wetland Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32 Apply Potential to the PFC Assessment.........................................33 5. Assessing Hydrology Attributes and Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37 Item 1: Riparian-wetland area is saturated at or near the surface or inundated in “relatively frequent” events....................................40 Item 2: Fluctuation of water levels is within a range that maintains hydrologic functions and riparian-wetland vegetation . . . . . . . . . . . . . . . . . . . . . .49 Item 3: Riparian-wetland area is enlarging or has achieved potential extent . . . . .52 Item 4: Riparian-wetland impairment from the contributing area is absent......56 Item 5: Water quality is sufficient to support riparian-wetland plants............60 Item 6: Disturbances or features that negatively affect surface- and subsurface-flow patterns are absent........................................64 Item 7: Impoundment structure accommodates safe passage of flows (e.g., no headcut affecting dam or spillway).................................68 6. Assessing Vegetation Attributes and Processes..............................75 Item 8: There is adequate diversity of stabilizing riparian-wetland vegetation for recovery/maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77 Item 9: There are adequate age classes of stabilizing riparian-wetland vegetation for recovery/maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .80 vi Contents Item 10: Species present indicate maintenance of riparian-wetland soil-moisture characteristics................................................84 Item 11: Stabilizing plant communities are present that are capable of withstanding overland flows (e.g., storm events, snowmelt), and wind and wave actions, and can resist physical alteration ...............86 Item 12: Riparian-wetland plants exhibit high vigor . . . . . . . . . . . . . . . . . . . . . . . . . . . .90 Item 13: An adequate amount of stabilizing riparian-wetland vegetation is present to protect soil surfaces and shorelines, to dissipate energy from overland flows and wind and wave actions, and to resist physical alteration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .93 Item 14: Abnormal frost or hydrologic heaving is absent........................97 Item 15: Favorable microsite condition (e.g., woody material, water temperature) is maintained by adjacent site characteristics ..........101 7. Assessing Soil and Geomorphic Attributes and Processes ..................104 Item 16: Accumulation of chemicals affecting plant productivity/composition is absent..................................................................104 Item 17: Saturation of soils (i.e., ponding, flooding frequency, and duration) is sufficient to compose and maintain hydric soils............................114 Item 18: Underlying geologic material/soil material/permafrost is capable of restricting water percolation ..............................................119 Item 19: Riparian-wetland area is in balance with the water and sediment being supplied by the watershed (i.e., no excessive erosion or deposition) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .122 Item 20: Islands and shoreline characteristics (i.e., rocks, coarse and/or large woody material) are adequate to dissipate wind- and wave-event energies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .124 8. Finalizing the PFC Assessment ..............................................127 Determine the Functional Rating..............................................127 Complete the Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .131 Appendix A—Assessment Forms and Instructions..............................133 Appendix B—Matrix of Correlated Items........................................152 Appendix C—Quantitative and Semiquantitative Techniques for Validating or Monitoring Assessment Items............................................154 Appendix D—Applying Potential to the Assessment of Altered Lentic Sites....166 Appendix E—Example Assessments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .175 Appendix F—Cowardin Classification System...................................193 Appendix G—Hydrogeomorphic Classification .................................199 Glossary.........................................................................202 Literature Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .210 Contents vii List of Figures and Tables Figure 1. Recommended steps in the integrated riparian management process . . . . . . 7 Figure 2. Alternating/repeating lotic and lentic complexes..........................23 Figure 3. Degradation of a lentic meadow to an incised stream system (diagram)....35 Figure 4. Degradation of a lentic meadow to an incised stream system (photos).....36 Figure 5. Determining depth to water table or saturated soil conditions.............41 Figure 6. Mud cracks and algal crusts provide evidence of inundation in seasonally flooded wetlands ...................................................42 Figure 7. Debris accumulates along the high-water level or upstream side of woody stems ...............................................................43 Figure 8. Various gages record surface and groundwater stages . . . . . . . . . . . . . . . . . . . .44 Figure 9. Encroachment by FAC and FACU species where OBL and FACW species are expected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46 Figure 10. A “bathtub ring” of bare ground between seasonal high- and low-water levels ...............................................................51 Figure 11. Dead upland plants can indicate a rising water table and enlarging riparian-wetland area................................................53 Figure 12. Progressive dewatering of wet meadow as gullies expand . . . . . . . . . . . . . . . .54 Figure 13. The effects of a stable versus declining water table on tree canopy........55 Figure 14. Process to determine if watershed factors contribute to riparian-wetland impairment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57 Figure 15. Inputs and losses of water in a riparian-wetland area.....................59 Figure 16. Highly saline “produced” waters leaked and killed a cattail community ...........................................................62 Figure 17. Effluent from buried mine tailings discharged acid and metal into surface water .......................................................62 Figure 18. Illustration of progressive impacts from trampling........................66 Figure 19. Deep void spaces can drain soils and cause loss of soil moisture . . . . . . . . . .67 Figure 20. A cracked, slumped, and broken concrete spillway may be unstable . . . . . .71 Figure 21. A 3-5 m deep headcut migrating through a spillway threatens dam integrity........................................................71 Figure 22. Water overtopping a dam can cause dangerous erosion of the dam.......72 Figure 23. Cavities (or soil piping) in a dam caused by a large leak in a corroded pipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73 Figure 24. Scattered individual Nebraska sedge shoots and leaves not reproducing adequately ...................................................82 Figure 25. Age class population distribution shapes.................................83 Figure 26. Stabilizing vegetation exhibits highly developed roots and rhizomes . . . . .88 Figure 27. Pugged, hummocked, and trampled soil surface in a mesic meadow......89 Figure 28. Fence line where shrubs with high vigor exist on only one side ...........92 Figure 29. Shoreline not covered with an adequate amount of stabilizing vegetation .......................................................95 Figure 30. Normal and abnormal frost heaving . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100 Figure 31. Drier conditions result after fire removed forest cover and potential nursery logs adjacent to a riparian-wetland area...............................102 viii List of Figures and Tables