Résumé :
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This study was conducted to develop a methodology for rehabiliting a silt-polluted stream and to measure the biological impact of rehabilitation on the insect community. Field work was conducted in the East Fork and main stem of Emerald Creek in northern Idaho. The study involved natural fiels conditions and laboratory simulation. Six control sites were selected based on similarity of flow, substrate type and channel geometry. Sediment samples were tagged and monitered, hydraulics structures were constructed for modification, and changes in the aquatic insect community were studied in conjuction with physical changes in the streambed. In-stream alterations proved to be effective for increasing sediment transport, thus improving insect and fish habitat. Other improved conditions included increasing pool-riffle ratios and higher values of percent cobble. Due to its hydrological cyle, Emerald Creek can flush large amounts of fine sediments per year. But until the source of pollution sediments is eliminated, excessive loading will continue.
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