Tanana River Watershed
Alaska Boreal Forest Council and GW Scientific
Description and Purpose: Habitat suitable for regeneration and growth is essential to the continued existence of all plant and animal species. In the case of anadromous fish, such as salmon, such habitat is closely coupled to watersheds and watershed processes. In the Tanana Basin of Interior Alaska near Big Delta, the complex network of main channels, backwaters, sloughs, and spring-fed clearwater streams is generally considered to be important to fish spawning and rearing. Water movement through spawning beds is thought to be a key process. Perfusion through the spawning beds of water containing sufficient heat to prevent freezing and oxygen to sustain life is necessary for the successful propagation of, for example, fall-spawning chum salmon.
Future development in the Basin and the operations associated with extraction activities, such as forest cutting and mining, have the potential to interfere with fishery and water resources. Such operations typically require some means of access. Surface access routes to proposed timber sales and mine sites in the area, such as winter roads and ice bridges, would have to cross likely spawning areas and potentially could interfere with ground-water flows and water qualities that support the fishery.
The current project uses the pattern of open-water patches in the general ice cover as a way to detect the influence of relatively warm ground-water during winter. Spring-fed streams tend to be clear and ice-free year round, so that an ice-based approach is not possible in these cases. However, our instream surveys reveal evidence of upwelling that we believe can be photographed from lower altitudes. Therefore we propose the use of low-altitude aerial surveys to gain evidence of upwelling in clearwater streams in the study area.
Regarding the aerial survey work already done, the accumulated inventory of photos is larger than originally anticipated due to extending the area covered. For this reason, and because considerable effort went into evaluating and incorporating more efficient image processing software, it will take more time than expected to complete this phase of the work. Therefore, we propose more time to do this.
Aerial surveys looking for evidence of upwellings cover a lot of area quickly and relatively inexpensively and are valuable in this regard. However, a more fundamental understanding of the geohydrologic processes that control upwellings is sorely needed. An opportunity recently arose to begin to achieve that understanding, specifically, by the establishment of an index site (array of pressure and temperature sensors) to monitor ground-water and stream-water interactions along a section of a spring-fed stream.
Information needed to know how to protect these forest and fish resources is important for resource managers. Moreover, there is widespread public interest in the project. We believe that the information generated by this index site will ultimately enable managers to make better decisions founded upon sound science. The publicly accessible website will, we believe, add a new dimension of value to the project, and perhaps be an attractor for future support. Note that the establishment of the index site, use of supercomputer modeling facilities, and the dedicated new website and with its many associated benefits, account for only a small fraction of the total grant cost.
Evaluation of Success:
Existing photographs of the river corridor are already being used by ADFG in decision-making. The value of these images will be multiplied as georeferenced images become available. Actual use of the information by agencies and the public will be an important measure of its value.
Engineering and Environmental Internet Solutions (www.eeinternet.com) will provide Internet usage summary statistics for the project.