Physical, biological, and biogeochemical response of a northeastern river to a severe flood

The Suncook River in Epsom, New Hampshire dramatically changed course on May 15, 2006 after ten inches of rain fell over a three day period. This avulsion created one entirely new stream reach, drastically reduced flow in a second reach, and delivered large amounts of suspended sediments to an otherwise un-impacted downstream reach. We have used this opportunity to investigate the duration and extent of physical, biological, and biogeochemical disturbance in this northeastern river. Towards this end, we have collected data from three impacted reaches (new channel, dewatered channel, and sediment laden channel downstream of the avulsion) as well as upstream reference sites.  We are continuing to document changes in water physiochemistry (including temperature, pH, conductivity, dissolved oxygen, suspended solids, DOC, DON, NH₄⁺, PO₄, total phosphorus, NO₃^-, Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl^–, SO₄^2-), stream biota (including benthic macroinvertebrates and fish), and ecosystem processes (stream metabolism) of the affected reaches and upstream reference sites. Preliminary results suggest that while biogeochemical disturbance becomes ameliorated almost immediately, stream geomorphology and biota take longer to recover.