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BLM LIBRARY A Framework 88049694 for ANALYZING the HYDROLOGIC CONDITION of WATERSHEDS QL -June 1998- 84.2 .L35 no. 405 rllASv U.S. Department ofAgriculture $ U.S. Department ofthe Interior c.2 Forest Service Bureau ofLand Management Though this document was produced through an interagency effort, the following BLM numbers have been assigned for tracking and administrative purposes: BLM Technical Note 405 BLM/RS/ST-98/004+72 1 -^9fi>^c fe,9^ 2r & A Framework for ANALYZING the HYDROLOGIC CONDITION of WATERSHEDS by McCammon Bruce John Rector A 9? Karl Gebhardt a o> v ° -June 1998- U.S. Department ofAgriculture Forest Service U.S. Departmentofthe Interior Bureau ofLandManagement Acknowledgments Interagency coordination among the Forest The hydrologic condition protocols team was Service (FS), Bureau ofLand Management (BLM), responsible for developing the overall analytic and other agencies was essential to successful process. Initial team members faced an extremely completion ofthis guidance. The following difficult task ofdeveloping an analytic approach individuals participated on teams that developed to be applied extensively throughout the various portions ofthe information contained in United States. The following individuals initially this document. consulted on this effort and were members of a team led by John Rector: The core team was responsible for steering the developmental phases ofthis guidance and for overall coordination. The team consisted of: Richard Burns FS BLM Jim Fogg Warren Harper .FS Leslie Reid FS . . . Ron Huntsinger .BLM Chris Knopp FS . . . Nancy Lopez U.S. Geological Survey Bruce Zander Environmental Protection Larry Schmidt FS Agency Dan Muller BLM Bruce McCammon .FS The hydrologic unit protocol team, consisting of . Karl Gebhardt BLM Bruce McCammon and Ervin Cowley worked to John Rector FS adopt current national standards for delineating Keith McLaughlin .FS watersheds. Bob Pierce ofUSGS also provided . . Ervin Cowley BLM significant contributions. Doug Ryan FS Don Brady Environmental Protection The core team extends its appreciation to Agency individuals who assisted with documenting and Jack Frost Natural Resources preparing this guidance. These individuals Conservation Service include: The hydrometeorological protocols team was PennyWilliams FS responsible for developing national-scale basic MargaretTrujillo .BLM . . . data presentation requirements. The team was Linda Hill BLM BLM led by Keith McLaughlin and consisted of: Janine Koselak Dennis Murphy .BLM Further acknowledgement is extended to Jim . . . Dennis Kelly FS Greenfield (EPA) for his support and willingness Joe Frazier BLM to test and apply this guidance on the Chattooga Mike Solomon FS River in Georgia. Lee Chavez FS Chester Novak BLM Mike Kuehn FS Jim Harte BLM A Framework forAnalyzing the Hydrologic Condition ofWatersheds i Table Contents of Acknowledgments Introduction 1 Purpose 1 Overview ofthe Analysis Process 1 Analysis Preparation 3 Delineating Watersheds 3 Developing Case Files for Core Hydrotneteorological Data 3 The Hydrologic Condition Analysis Process 5 Step 1 Characterize the Watershed 5 Step 2 Rate Factors 7 Step 3 Identify Important Factors 12 Step 4 Establish Current Levels 16 Step 5 Establish Reference Levels 17 Step 6 Identify Changes and Interpret Results 18 AppendixA: Core Hydrometeorological Data and Information Protocols 25 Appendix B: Watershed Case File 29 — Appendix C: Interdisciplinary Team Planning Using the Results 33 Appendix D: Glossary 35 Literature Cited 37 A Framework forAnalyzing the Hydrologic Condition ofWatersheds iii Introduction Purpose comprehensive analysis ofthe watershed. When merged and integrated with other resource The Bureau of Land Management (BLM) and information, hydrologic condition becomes the Forest Service (FS] are responsible for man- part ofthe basis for identifying management aging natural resources on public lands. While opportunities and priorities, and for developing the numerous resources on the public lands are alternatives to maintain, enhance, or restore diverse, they are also interrelated, which means watershed function. that management actions pertaining to one resource will also impact others. The purpose ofthis guidance is to provide a national framework for hydrologic analysis and Water is one resource that has the potential to related protocols as components of more com- impact numerous other resources. For the BLM prehensive interdisciplinary watershed analysis. and FS, an important part offulfilling their This guidance outlines a process for identifying resource management responsibilities involves the essential factors needed to describe hydro- gaining an understanding ofthe physical logic condition from a vast array of possible processes that govern the flow (F), quality (Q), factors. The information assembled during the process enables those who conduct hydrologic and/or timing (T) ofwater. Understanding these processes requires, among other things, informa- analyses to participate effectively with other tion about precipitation, ground cover, vegeta- interdisciplinary team members in addressing ecosystem and resource management planning tion, soils, geology, runoff, channels, floodplains, and riparian areas for each watershed. issues. The process helps to organize existing information about a watershed in the form ofa Watersheds are characterized by meteorological, watershed case file, which displays and interprets surface- and ground-water, and physical and bio- critical hydrologic information and supplements other resource information during decisionmaking logical factors functioning within the context of natural and human disturbance regimes. The processes. flow, quality, or timing ofwater within a watershed is regulated by these factors. Watershed characteristics must be analyzed and interpreted Overview of the using known scientific principles about hydrologic and hydrometeorological processes to Analysis Process describe hydrologic condition. The analysis and interpretation require basic hydrologic knowl- Hydrologic condition analysis results in an edge, knowledge ofthe area, and competency in understanding ofthe interrelationships among using hydrologic tools and making judgments meteorological, surface- and ground-water, and regarding hydrologic processes. physical and biological factors that influence the flow, quality, and/or timing of water. The Hydrologic interpretations provide fundamental magnitude, direction, and rate of change are the information about the linkages between terres- expression ofhydrologic condition. The deter- trial features or processes and associated aquatic mination ofhydrologic condition should, there- or biological resources. They are intended to be fore, focus on the analysis ofthe factors that combined with information developed by other most directly influence changes in the specific disciplines to achieve an integrated and watershed ofinterest. Watershed characteristics A Framework for Analyzing the Hydrologic Condition of Watersheds 1 that are not subject to change by management The analysis steps follow a logical sequence that activities (e.g., geology, landform, precipitation) will provide the basis for supporting professional are fundamental in defining physical limits within estimates and judgements resulting in credible which management actions can be expected to conclusions. The products ofone step provide influence water flow, quality, or timing. Analysis information for subsequent steps. The following and documentation ofthese characteristics are steps presume that some prework has been needed to support interpretations ofhydrologic accomplished, including delineating the condition and to defining the limits of watershed and assembling pertinent data: management influence over the physical system. Step 1. Characterize the watershed Because watersheds vary tremendously across Step 2. Rate factors the country, analysts need the flexibility to Step 3 Identify important factors . select the watershed characteristics that are Step 4. Establish current levels most relevant for the watershed they are consid- Step 5. Establish reference levels ering. The analysis procedure outlined in this Step 6. Identify changes and interpret results document is intended to provide the needed flexibility. The focus is on a process of analysis The analytic process will provide a starting point rather than on a prescribed or fixed set offac- for discussion of hydrologic issues, related tors that drive the analysis. This approach resource issues, and questions to be addressed allows analysts to use existing tools (e.g., region- through ecosystem and resource management al curves, nomographs) and to adapt the process planning. The analysis is intended to be water- based on available information (local watershed shed-specific, dealing only with factors associat- case files) and local or regional conditions and ed with the specific watershed being analyzed. needs. It is expected that standard procedures It is likely that the analytic factors will differ will be used to analyze factors indicative of between watersheds, especially watersheds in hydrologic condition [e.g., Techniques ofWater substantially different geographic settings. The Resources Investigations ofthe United States expectation, however, is that within a common Geological Survey and An Approach to Water landscape unit, such as those defined by Bailey Resources Evaluation ofNon-Point Silvicultural (1995) or Maxwell et al. (1995), the suite of Sources (A Procedural Handbook - USDA)]. important processes will likely be similar. This Use ofexisting information brings with it a wide means that the knowledge gained in one analysis range of reliability and confidence in the values. may be used to shape the next. It is very important for analysts to document the level ofconfidence and the reliability oftheir estimates and conclusions. It is important to document data voids that have decreased the reliability ofconclusions. 2 A Framework forAnalyzing the Hydrologic Condition ofWatersheds