Upper Klamath Lake Watershed Assessment The earliest aerial photography of the assessment area was taken in 1940. Several USFS watershed analyses used these photos to assess the changes that have occurred in riparian areas since that time. These observations, where applicable, have been included in the individual watershed descriptions. Results Historic / Potential Riparian Condition An assessment of the seven ecoregion types included in the area shows the variety of typical land cover conditions across the entire subbasin (Bryce and Woods 2000, Kuchler 1964) (Map 1-3). Within these ecoregions, the riparian areas differ from the uplands because of different soil, hydrologic, and topographic factors. In the highest elevations of the subbasin, the Cascade Subalpine/Alpine ecoregion generally lacks defined riparian areas but contains alpine meadows with scattered stands of mountain hemlock, whitebark pine and subalpine fir. Typical riparian areas in the High Southern Cascades Montane Forest include lodgepole pine, mountain hemlock, white fir and Shasta red fir. Douglas-fir (Pseudotsuga menziesii) will likely be found in the riparian areas of the Southern Cascade Slope, with ponderosa pine and white fir occurring throughout. Higher elevations within the Pumice Plateau Forest will have white fir, with lodgepole pine located in depressions. Higher elevations of the Fremont Pine/Fir Forest would also contain lodgepole pine in the wetter areas, with western juniper in lower altitudes. While ponderosa pine is typically found in the drier sites of the other ecoregions, it is found in the wetter areas of the Klamath Juniper Ponderosa Pine Woodland. The Klamath/Goose Lake Warm Wet Basins ecoregion did not historically include a woody overstory (in this document the term “woody” is used to define persistent vegetatation), but was dominated by tules, cattails, and sedges. Upper elevation channels would have been high gradient, fed by snow-pack, and well shaded by a combination of surrounding topography and trees. Areas adjacent to riparian zones would have been characterized by large diameter coniferous trees, which would have contributed woody debris to these reaches. Large ponderosa pine and Douglas-fir, found within some of these zones, survived periodic fire and attracted large scale logging activities as early as the late 1800’s (USFS 1996a). Much of the subbasin lowlands were comprised of wet, forested areas including lodgepole pine, aspen (Populus tremuloides) and cottonwood (Populus balsamifera ssp. trichocarpa), with willows (salix spp.) found along river corridors (USFS 1994). These communities transitioned into emergent wetlands surrounding the fringes of Upper Klamath and Agency lakes. On the valley floor, the deposition of glacial till and fine-grained sediments allowed stream channels to shift along the valley floor in response to peak flows and storm events (USFS 1996a). Channels would have been complex, well shaded, and contained significant quantities of woody debris. Current Riparian Conditions This section describes riparian conditions and characteristics shared by all fifth-field watersheds. Page 6-2 FINAL – June 2010 Chapter 6 – Riparian Assessment Watershed Assessment Upper Klamath Lake Extremely porous subsoil and high infiltration rates dramatically affect the hydrologic patterns in the subbasin. Riparian zones, while functioning as significant drainages for water conveyance, may not hold surface water during certain times of the year. As a result, several streams in the subbasin have both perennial and intermittent reaches, depending upon substrate and stream gradient, at various locations (USFS 1996a, Gannett et al. 2007). There is a remarkable difference in the amount of riparian canopy between high and low elevation riparian areas in the subbasin. In general, forested upland streams managed by USFS are well vegetated and have been recently protected, after decades of logging. This management, in combination with fire suppression, has led to a riparian landscape condition broadly characterized by dense stands of young trees, with occasional patches of old growth containing large diameter mature trees. Since most of the large trees and woody debris were intentionally removed from the riparian zones (for both logging and fire prevention), it may be several decades before these areas are able to provide meaningful quantities of large wood back into the streams. Overall, USFS lands have a relatively high degree of riparian cover and buffer in forested areas resulting from guidelines that restrict activity in riparian areas. Oregon Riparian Management Areas (RMAs), established for forestry and agricultural use on private and public land, designate minimum buffers around streams to protect riparian vegetation. The width of these buffers, or setbacks, is based upon ownership (state, federal or private), the size of the stream, and whether or not the stream is fish-bearing. The largest RMAs are for perennial streams on federal forest land, requiring a 320 foot buffer, or the equivalent of two site potential trees. Intermittent streams on federal land require buffers of 160 feet, or one site potential tree. Logging activities are prohibited within these buffers, unless they are for restoration purposes. Buffers on private forestland vary, depending on stream size and fish species present. Fish-bearing streams require 20-100 foot buffers, depending on the streamflow, and non-fish bearing streams require 0-50 foot buffers. Certain logging activities may be allowed within the buffers, but in general, no harvest can occur within 20 feet of the stream and all understory within 10 feet of the stream must remain intact (ODEQ 2009). All perennial streams on agricultural land, public or private, have buffers determined by the subbasin’s individual Agricultural Water Quality Rules. These rules are established under Oregon’s Agricultural Water Quality Management Act (1993), which was enacted to support the Federal Clean Water Act (ODA 2008). Grazing is another resource activity that occurs on a small proportion of USFS property in the subbasin. Riparian meadows are the principal locations being used for grazing, typically including cattle and horses. Management considerations include proximity to fish-bearing streams and the potential for sediment to enter those streams. The grazing allotment located along Fourmile Creek has been fenced to exclude cattle and horses, providing a 100-foot buffer from the stream (USFS 2006). In contrast to riparian areas in the higher elevations, many of the low elevation stream reaches currently have little or no riparian cover (Figure 6-1, Aerial Photo of a Channel Lacking Overhead Canopy Adjacent to Forested Land). In the lowland areas, which are mostly privately FINAL – June 2010 Page 6-3 Chapter 6 – Riparian Assessment Upper Klamath Lake Watershed Assessment owned, grazing has altered vegetative conditions over time. Most of the willows and hardwoods that once occupied portions of the lowland riparian vegetative zone are now gone. Various watershed analyses and interviews have identified streams throughout the subbasin, concentrated in the low elevations, that are incised and support limited riparian vegetation. However, it is important to note that not all streams have the potential to naturally support woody riparian vegetation due to bank aspect and stream gradients (e.g., less than ½% gradient). In streams that can naturally support woody riparian vegetation, this vegetation plays an important role by maintaining bank structure with a rooting network, shading stream surfaces, and contributing to terrestrial and aquatic habitat for species. Absence of woody vegetation in riparian areas results in poor stream shading, decreased opportunities for large wood recruitment, and thus low quality aquatic habitat. The structural diversity of streams has been further compromised by the fact that wood has been intentionally removed from most streams and streams have been channelized. Re- establishing riparian vegetation has the potential to reduce bank erosion, improve water quality and increase available habitat. Recent efforts to restore riparian communities along degraded stream reaches in the subbasin are discussed later in this chapter, and in further detail in Chapter 9, Fish and Fish Habitat Assessment. Figure 6-1. Aerial photo of a channel lacking overhead canopy adjacent to forested land (DEA 2009). Riparian conditions determine the extent to which solar radiation can increase water temperatures within the subbasin. Research has shown that shade-producing vegetation is an effective way to prevent elevated water temperatures. By allowing vegetation communities in riparian areas to grow to their site ecological status potential, shade provided to streams will be increased and stream temperatures will remain cooler in response to this increased shade (USDA and USDI 2003). Potential riparian land cover is the land cover that could grow and reproduce along a stream given certain site specific hydrologic, soil, and vegetative conditions (USDA and USDI 2003). Effective shade was used as a surrogate measure for solar radiation loading Page 6-4 FINAL – June 2010 Chapter 6 – Riparian Assessment Watershed Assessment Upper Klamath Lake capacity in the Upper Klamath Lake Drainage TMDL instead of actual solar loading values (USDA and USDI 2003). Figure 6-2 (Riparian Forest Effect on Streams as a Function of Buffer Width) shows that, in general, the cumulative effectiveness of shade from riparian vegetation