Anchor sites There were no anchor sites identified in Maynard. Secondary branches No secondary branches were identified. . Riparian corridor Dimensions and location Describe the lineal dimensions and location of deciduous, coniferous, and open canopy. The first 2,000 lineal feet of Maynard Creek has good canopy cover (75%). However at 2,500 ft there is a 1,000ft reach with little to no harvest buffer which has resulted in extensive solar exposure. Again at 4,200ft a narrow harvest buffer exhibits heavy blow down loss which has also resulted in significant solar exposure. Each of these upslope impacts contribute to the temperature degradation observed in the mainstem of Rock Cr that have been described in this document as the sum total of the cumulative impacts occurring in tributaries just exactly like Maynard. Recruitment potential What is the recruitment potential and time frame for delivery to the channel? Riparian recruitment potential for Maynard Cr is good. Because the active channel width is only 6 ft , both deciduous and coniferous contributions from the riparian will be well retained and form functional instream wood complexity even at winter flows. Thermal problems Describe the relationship between riparian condition and thermal problems in the aquatic system. Include locations and causes. No temperature data was available for Maynard, but the solar exposure associated with the lack of riparian buffer associated with upslope harvest activity has been identified as a primary limitation for salmonids on the Rock Cr basin scale. Bear Creek (Rock Cr) assessment Bear Creek enters Rock Creek 670 ft upstream from Rock Creeks confluence with the mainstem . The confluence is in in downtown Vernonia. Migration barriers There were no adult migration barriers observed within the inventory.
Issues All of the prescriptions listed above are included in the following condensed discussion of general issues, goals, methods, complications and results. Mainstem Rock Cr temperature limitations from its confluence with the mainstem Nehalem to RM 12 on Rock Cr impair anadromous distribution and abundance. This is a cumulative problem that begins in many head water tributaries of Rock Cr and in the upper mainstem from the impacts of upslope harvest activities. Many riparian corridors (including non fish bearing and fish bearing stream corridors) were recently logged with no riparian protection retained to protect the aquatic corridor from solar exposure. Because temperature limitations in the mainstem limit its summer carrying capacity, it is also important to protect, maintain and enhance the riparian buffers that currently exist on small private and industrial timber ownership. Because temperature limitations in the mainstem limit its summer carrying capacity, it is important to provide unimpeded escape routes to upstream cold water refugia. Therefore the restoration of passage for juveniles through culvert replacement is critical. The legacy of industrial timber extraction upslope and throughout type N streams has led to a precipitous decline in the system’s capacity to provide LWD to the aquatic corridor. This lack of wood complexity is the root cause of the channel degradation that can be observed today in simplified channel habitats scoured to bedrock. The ability of full spanning log structures to raise the stream adjacent water table and to provide vast summer water storage capacity to mitigate for elevated summer flows is well established. The legacy of industrial timber extraction has reduced the riparian corridors capacity for the provision of the coniferous LWD that would historically have been the foundation for the retention and sorting of high quality spawning gravels for Coho. The declining abundance of beaver dam habitat in conjunction with low wood densities has accelerated the migration rates of substrates (including spawning gravels) out of the Rock Cr headwaters where they historically were trapped and retained in the headwater locations utilized by spawning salmonids. Low instream wood densities are resulting in the loss of spawning gravel storage capacity which is currently the primary limitation for the production of coho and cutthroat trout in the Rock Cr basin. Goals Initiate a change in the trajectory of the mainstem Rock temperature limitation utilizing a broad range of prescriptions that simultaneously addresses the multiple issues that combine to create the downstream cumulative impacts limiting salmonid production.