Chapter One Watershed Analysis Objectives 1 CHAPTER ONE WATERSHED ANALYSIS OBJECTIVES -------------------------------------------------------------------------------------- Watershed analysis is essentially ecosystem analysis at the watershed scale. Federal agencies are directed to use an ecosystem management approach to manage public lands. The Record of Decision (ROD) for Amendments to Forest Service and Bureau of Land Management Planning Documents Within the Range of the Northern Spotted Owl, the Northwest Forest Plan (NFP (1994)), recommends that watershed analysis be conducted within watersheds where management activities are being proposed, in order to understand the consequences of management actions prior to implementation. This is the primary reason for conducting the Copeland-Calf Watershed Analysis. The objectives of the Copeland-Calf Watershed Analysis are to: Develop a scientifically based understanding of the dominant physical, biological, and human processes and features and their interactions within the watershed. Use this understanding to sustain the productivity of natural resources in order to meet human needs and desires. Use this understanding to develop the basis to estimate direct, indirect, and cumulative effects of our management activities. Relate these features and processes to those occurring in the river basin or province. Guide the general type, location, and timing of management activities within the watershed. Identify restoration and rehabilitation opportunities within the watershed. Establish a watershed context for evaluating project consistency with the NFP Standards and Guidelines (S & G) for management areas and land allocations. Establish a watershed context for evaluating project consistency with the Aquatic Conservation Strategy (ACS) objectives. Establish a consistent, watershed-wide context for implementing the Endangered Species Act (ESA), including conferencing and consultation under Section 7. Copeland-Calf Watershed Analysis 2 Chapter One Watershed Analysis Objectives Establish a consistent, watershed-wide context for the protection of beneficial uses identified by the states and tribes in their water quality standards under the Federal Clean Water Act. Watershed analysis is not a detailed study of everything in the watershed; instead, it is built upon the most important issues that are discussed in Chapter Five of this document. Watershed analysis is not a decision making process. It is not intended to take the place of detailed, site- specific project planning and analysis under the National Environmental Policy Act (NEPA). This watershed analysis report is a dynamic document. Additions or changes to this document may occur as new information becomes available. This is the first iteration of the Copeland-Calf Watershed Analysis. Copeland-Calf Watershed Analysis Chapter Two Characterization 3 CHAPTER TWO CHARACTERIZATION -------------------------------------------------------------------------------------- INTRODUCTION The purpose of this chapter is to: Identify the dominant physical, biological, and human processes and features of the watershed that affect ecosystem function or condition. Relate these features and processes to those occurring in the river basin or province. Provide the watershed context for identifying elements that need to be addressed in the analysis. Identify, map, and describe the most important land allocations, plan objectives, and regulatory constraints that influence resource management in the watershed. GEOGRAPHICAL LOCATION AND DESCRIPTION The Copeland-Calf Watershed is located between Glide and Toketee, approximately 50 miles east of Roseburg, Oregon on the Diamond Lake and North Umpqua Ranger Districts of the Umpqua National Forest (UNF (Figure 1)). The study area of 49,019 acres is located in all, or portions of the following: T26S, R1, 2, and 3E, T27S, R1, 2, and 3E, Willamette Meridian, Douglas County, Oregon. This includes the area from near Illahee Rock, south along Rattlesnake and Rhododendron Ridges to Mud Lake Mountain; westerly along Forest Road 2715 to Snowbird Shelter; northward following Calf and Bradley Ridges; then east on Forest Road 4760 to the point of beginning. Prominent features located within the Copeland-Calf Watershed Analysis area are portions of the North Umpqua River and Boulder Creek Wilderness, as well as State Highway 138, Eagle Rock Campground, Twin Lakes, Eagle and Rattlesnake Rocks, and several holdings of private land. Major stream drainages located within the watershed are Copeland, Calf, Dry, and Deception Creeks, as well as a portion of the North Umpqua River. All creeks are tributaries to the North Umpqua River. Copeland-Calf Watershed Analysis 4 Chapter Two Characterization Relative Location of Copeland-Calf Watershed Analysis Area Figure 1. Relative location of Copeland-Calf Watershed Analysis area. LANDSCAPE OWNERSHIP AND ALLOCATION The Copeland-Calf Watershed is primarily public land administered by the U.S. Department of Agriculture (USDA), Forest Service. There are several holdings of private land, totaling approximately 576 acres (Figure 2). The NFP allocates the area to approximately 40,467 acres of Key Watershed, 45,514 acres of Late-Successional Reserve (LSR) and 2,970 acres of Congressionally Reserved land (Wild and Scenic corridor and Wilderness), as shown in Figure 2. Portions of these land allocations may overlap each other within the watershed. Copeland-Calf Watershed Analysis Chapter Two Characterization 5 Land Allocation and Key Watershed in the Copeland-Calf Watershed Figure 2. Land allocation and Key Watershed within the Copeland-Calf Analysis area. Copeland-Calf Watershed Analysis 6 Chapter Two Characterization CORE TOPICS GEOLOGY AND GEOMORPHOLOGY Geologic Setting The Cascades volcanic arc (chain) that extends from northern California into southern British Columbia is thought to have originated about 40 million years ago (Ma) as a consequence of subduction of the Pacific oceanic plate beneath the leading edge of the westward moving North American continental plate. Partial melting of iron and magnesium-rich sea floor crust takes place at depths of 100 or more kilometers, within the Cascadia Subduction Zone. Magma generated deep beneath the continental margin ascends through the Earth’s crust and periodically erupts onto the surface in the form of extrusive lava flows and explosively expelled fragmental (pyroclastic) deposits (McBirney 1978; Duncan and LaVerne 1989, Priest 1990). Within Oregon, the Cascade Range is delineated into two physiographic sub-provinces, the older and deeply eroded Western Cascades and the present day (volcanically active) High Cascades that forms its topographic crest (Peck, et al. 1964). Lithology The Copeland-Calf Watershed Analysis area lies within the deeply incised western flank of the Cascade Range and is mainly underlain by a diverse and crudely layered succession of variably altered volcaniclastic deposits, lava flows, and related intrusive rocks that are collectively assigned to the Tertiary age “Little Butte Group” (Peck, et al 1964). The Little Butte Group was deposited between 35 and 17 Ma, during the period of Western Cascade volcanism (Peck, et al 1964, Sherrod and Smith 1989, Walker and MacLeod 1991). Lava flows and intrusive rocks within the Copeland-Calf Watershed Analysis area consist of resistant, moderately fractured basalt, basaltic andesite, and dacite. Volcaniclastic deposits are comprised of a diversity of relatively soft, poorly bedded tuffs and volcanic breccias that originated from explosive volcanism, or from large-volume mudflows (lahars) and massive debris avalanches. Fluvial reworking of primary, unconsolidated, volcaniclastic deposits formed a variety of weakly resistant, well-bedded sedimentary strata comprising tuffaceous siltstone, sandstone, and conglomerate (Sherrod and Smith 1989, Walker and MacLeod 1991). A local sequence of resistant, Quaternary age, intracanyon lava flows termed the “basalt of Toketee” crops out as a series of remnant benches and tablelands along the North Umpqua River. The basalt of Toketee is dated at roughly 760,000 to 780,000 years of age, thus it is associated with the recent episode of High Cascade volcanism (Sherrod 1986 and 1991). Unconsolidated (surficial) deposits found throughout the Copeland-Calf Watershed Analysis area include chaotic mixtures of fragmented rock and soil debris from massive landslides and stream alluvium (sand, gravel, cobble, and boulders) in floodplains and terraces. Copeland-Calf Watershed Analysis Chapter Two Characterization 7 Peck, et al. (1964), report that the succession of Little Butte Group strata along the North Umpqua River corridor approaches nearly 15,000 feet in thickness. Structurally, the volcanic and sedimentary strata in this region display a prevailing shallow inclination (dip direction) towards the east and are locally cut by a series of faults and related shear zones that follow northeast and northwest trends (Peck, et al. 1964, Sherrod and Smith 1989, Walker and MacLeod 1991). Volcanic, sedimentary, and intrusive rocks forming the Cascade Range are juxtaposed in highly complex geometric relationships. Individual deposits tend to be lens-like in form and are generally laterally and vertically discontinuous over relatively short distances. Complexity arises from a variety of controlling factors that include: a multitude of eruptive sites, various modes of deposition or emplacement, and the relative degree of landscape dissection (erosion)