Evaluating stream trout habitat on large-scale aerial color photographs

Abstract

Large-scale aerial color photographs were used to evaluate trout habitat by studying stream and streambank conditions. Ninety-two percent of these conditions could be identified correctly on the color photographs. Color photographs taken 1 year apart showed that rehabilitation efforts resulted in stream vegetation changes. Water depth was correlated with film density: 76.4 percent on normal color film and 73.5 percent on infrared film. Shadow-length measurements of streambank vegetation height were 86 percent accurate. A technique to measure the degree of shade created by streambank vegetation is described. The cost of large-scale color evaluation of trout habitat was estimated to be from $200 to $250 per mile of stream.

Citation

Greentree, Wallace J.; Aldrich, Robert C. 1976. Evaluating stream trout habitat on large-scale aerial color photographs. Res.Pap. PSW-123. Berkeley,CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station. 21 p