Stream Visual Assessment Surveys (SVAP)

Three major sections of Beaver Brook have been surveyed: the main stream (5 reaches surveyed: Main #1 to Main #5), one major tributary to the east (4 reaches, East Branch #1 to East Branch #5), and two major tributaries to the west (3 reaches surveyed for each: NW Branch #1 to NW Branch #3, SW Branch #1 to SW Branch #3). The overall reach ratings shown in the below map are an average of the ratings for each of the 14 scale scores used in the SVAP. You can select individual survey features by clicking on layers and selecting the feature you wish to view. Be sure to deselect the current feature before selecting a new feature. The camera icons can be selected to view photos of the downstream and upstream sections of a sampled reach. Camera icons can be turned off from the layers menu as well (deselect reach photos). If you wish, click on the link below the displayed map to view it in larger version on a separate page.

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So what does it all mean??? In general Beaver Brook is a nice place for brook trout as indicated by the overall reach status ratings: 10 reaches are rated “good”, three “fair”, and two “poor”. The reaches score high for riparian zone, canopy, water appearance, nutritional enrichment, temperature, channel condition, hydrologic alteration, bank stability, and invertebrate habitat. But they score low for pool status (very shallow), and fish barriers (Frost Mill Dam, Beaver Lake dam, and dam at head of SW branch).
The effects of erosion along the NW branch are evident in the results. First off, the NW #1 reach (one of the two poor reaches) forms an eroded gully. Sand predominates throughout that branch and the reaches along the main stream downstream from the mouth of the NW branch. In addition these reaches have high riffle embeddeness (a measure of how much sand has been deposited on the gravel bottom). Reaches on the main stream above the mouth of the NW branch have gravel bottoms and low riffle embeddedness.

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  1. Pingback: Stream Visual Assessment Survey Data Updated | Adopt-A-Trout

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