This paper presents instructions for constructing platforms that span the width of stream channels to accommodate the measurement of hydrologic parameters over a wide range of discharges. The platforms provide a stable, safe, noninvasive, easily constructed, and relatively inexpensive means for permitting data collection without wading in the flow. We have used the basic techniques described herein for building platforms on channels of small to medium size, up to 70 feet in width. Lightweight joists, commonly used in housing construction, form the primary structural support for the platform. The structures can be constructed by persons having only rudimentary knowledge of building practices and using simple tools. Cost estimates for materials range from $200 to $1,500 depending on the required length of structure. The platforms have been used successfully in measuring flow and sediment discharge in subalpine channels in Colorado and Wyoming during runoff events with 2 to 5 year return frequencies. They are quite stable and are safer than wading in channels with fast moving flow.