A Simple, Inexpensive Rain and Canopy Throughfall Collector

A field apparatus for collecting rain and canopy throughfall samples for volume and ion analyses was built and tested; detailed construction plans and material lists are included. Its advantages include simple wood and polyvinyl chloride pipe construction, low material costs, and an inert sample collector that remains covered until the rain begins. Covering the sample collector eliminates the collection of dry deposition, dust, and insects prior to a rain event. The triggering mechanism that exposes the collector opening consists of a counter-weighted cover that is released using water-soluble paper; no power source is needed. Laboratory tests determined the collector will trigger within the first 0.37-mm depth of rain (95% probability). Field comparisons of the collector with a nearby meteorological station rain gauge showed that identical amounts were measured (±1 mm).