An important source of metals to aquatic ecosystems is acidic, metalrich effluents from active or abandoned mining sites. Natural processes and remedial activities both lead to the neutralization of acidity, which results in the removal of dissolved metals from the water column. This process produces sediment deposits and suspended particles having high metal concentrations. The amount and characteristics of metal-contaminated sediments and stream water, collected from a high-gradient stream reach (North Fork, Clear Creek) located in the Front Range of Colorado, were studied. Deposited sediments and suspended particulate material are dominated by very fine-grained (colloids and fine silts) iron oxyhydroxide precipitates that contain high levels of copper and zinc. Sediments of this type are susceptible to in-situ formation, re-dissolution, and aggregation/disaggregation processes. These fine-grained sediments are suspected to be the key to metal transport, fate, and toxicity in this system. We examined seasonal variations in the following: 1) water column dissolved and suspended metal concentrations, 2) relative size distributions of suspended and bed sediments, and 3) acid-soluble metal content in coatings from streambed rocks. Metals were found to be temporarily stored in loose flocculated sediments, which accumulated in periods of low flow. Significant metal transport occurred as these sediments were re-suspended during high-flow hydrologic events, including spring snowmelt and a localized summer rainstorm.