BRUNEAU SAND DUNES, EAGLE COVE, ID: A GEOMORPHOLOGIC STUDY

The Bruneau Dunes State Park is located south of Mountain Home, Idaho and lies within Eagle Cove, a semi-circular 5.5 km diameter, 180-meter deep basin that formed by an old meander of the ancient Snake River. The Eagle Cove depression acts as a sand trap for wind blown sediments that sweep across the surrounding plateaus. Various methods used to ascertain the history and apparent stability of the dune features were grain size/hygroscopic moisture analysis, digitalized air photo comparisons, observation of local vegetation and water sources, collection of wind direction/speed data, and analysis of previous ground penetrating radar studies. We have determined these sand dune features, in particular the large dune complex and its central crater, to be relatively stable due to bimodal seasonal winds, the presence of a lake at the base of the large dune complex, vegetation on and around the dune, and the moisture-retaining silt content in the sands at the base of the large dune complex.