Effects of a depositional flood event on the hyporheos of a New Zealand stream

摘要: Abstract: We investigated the effects of a rare depositional fl ood (return period about 5 years) on hyporheos ood-prone river in southern New Zealand. The deposited 15–40 cm new sediment across most 42-m study site. On four occasions after (4 d, 17 35 49 d), pump samples (1 L volume) were col-lected for physicochemical and invertebrate analysis from three depths (10, 30, 50 cm). site was dominated by downwelling water, therefore, temporal variations interstitial physicochemistry probably refl ected surface water conditions. Composition immediately differed that subsequent occasions. Densities taxa similar sampling Nevertheless, depth distributions leptophlebiid nymphs (Ephemeroptera), Podonominae larvae (Chironomidae) mite Planaturus setipalpis all changed with time, consistent post-fl recolonisation recently depos-ited sediments underlying undisturbed sediments. Invertebrate not signifi cantly related to measured parameters, possibly because any such relationships obscured patterns. Our results indicate buried may be an important source colonists some epigean (surface-dwelling) during recovery disturbance associated deposition.