Lotic Riparian - Strahler Order Derived

This dataset is produced for the Government of Alberta and is available to the general public. Please consult the Distribution Information of this metadata for the appropriate contact to acquire this dataset. Riparian areas consist of the lands adjacent to streams, rivers, wetlands and lakes that are strongly influenced by the presence of water. They are often distinct from the surrounding landscape as the vegetation growth is very lush. These areas form a transition between dry land and open water and are characterized by the presence of hydrophilic vegetation and specific soil types. Riparian areas are usually very productive in terms of biomass and form critical wildlife habitat. Additionally, these areas often have standing water and are subjected to periodic flooding when high water levels fill the stream channel to the top of the bank. The term 'riparian' is derived from the Latin word for river bank. Riparian areas provide valuable food, shelter and travel corridors as well as an adjacent water source for wildlife and livestock. These zones are often densely vegetated and serve as stabilization against the erosive forces associated with lotic systems. Riparian areas provide filtration for surface runoff from the surrounding land and protect the water quality of flowing streams. They trap sediment and reduce the velocity of stream flow, thus reducing erosion in downstream areas. These areas provide detritus to their associated aquatic systems as well as a moderating effect on surface temperatures. The function of riparian areas in the landscape is regarded to be sufficiently critical that they are given special consideration in terms of the impact assessment resulting from human activities such as recreation, logging, oil and gas exploration, road construction and range management. Informatics Branch of Alberta Environment and Parks, Government of Alberta has been assigned the task of developing a provincial map of riparian areas. This project represents the initial effort to map riparian areas for the province. The riparian areas map is intended as input into ALCES (A Landscape Cumulative Effects Simulator), which is software developed by Forem Technologies. ALCES is being used to project the cumulative effects of various types of human activity on the landscape. This is accomplished by generating aspatial snapshots of regions within the provincial landscape and assuming that the current level of human impact continues. The methodology involved creating variable buffers by Natural Region based on Strahler Order coding for streams that had been merged with the associated perennial lakes. Higher Strahler Order codes were associated with wider buffers and drier Natural Regions were associated with narrower buffers. The result was a geodatabase of polygons that were intended to represent potential lotic riparian areas but the accuracy was poor. Landsat information and the Base Features Digital Elevation Model were incorporated to a minimal degree as refinements to the coverage but did not result in any improvement in the spatial accuracy of the data. This dataset is not recommended for use in riparian analysis. The Lotic Riparian - Digital Elevation Model Derived dataset, which was released in October 2011, is a better representation of the location and extent of riparian areas.

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