A streamside landslide delivered 60 000 m 3 of mixed-size sediment to the Navarro River, a sinuous gravel-bed channel (drainage area ‫؍‬ 535 km 2), at the end of the annual high-runoff period in spring 1995. The deposit formed a 9-m-high dam that partially breached within several hours, but recessional flows entrained little material until the following high-runoff season. The landslide afforded the opportunity to measure the evolution of a sediment wave from its inception to near-obliteration and, particularly, to test relative tendencies for translation and dispersion of a sediment wave in a natural gravel-bed channel. This study represents a simple case: The wave originated from a single input, the preexisting channel was relatively uniform, and resistant banks prevented adjustments in width. We surveyed channel topography over a 1.5-4.5 km reach centered on the landslide dam each year from 1995 to 1999, and we sampled bed material downstream of the dam in 1995 and 1997. Landslide material was coarser than ambient bed material, but all sizes were mobilized by subsequent peak flows. Abrasion of weathered and fractured graywacke sandstone landslide material was roughly an order of magnitude greater than the ambient river gravel. The sediment wave dispersed and mostly disappeared within a few years with no measurable translation. Sediment filled the reservoir created by the eroding landslide dam until throughput of bed load was restored in 1998. The stationary wave crest eroded until in 1999 it was Ͻ1 m higher

The present study aimed to relate aquatic macroinvertebrate community composition to agricultural intensity and landscape structure. A total of 360 streams were investigated within the Aller river basin in northern Germany. The study area is typical of central German arable agricultural regions, but the small streams were of low dilution potential. These streams were characterized for abiotic parameters (including modeled potential for diffuse inputs from agricultural sources) and macroinvertebrate communities, with data collected over a 17-year period. Spray drift potential did not correlate with community composition. In contrast, the relative index of runoff potential (RP) was negatively correlated with various measures of taxonomic richness and abundance. Community composition also was correlated with environmental parameters, including stream width, clay content of sediment, and presence of dead wood in sediment. The abundance of sensitive species decreased significantly during the main period of agrochemical use at sites of high RP but completely recovered by the following spring. Long-term decreased taxonomic richness and a shift to ecologically robust species also were observed at sites of high RP. The results suggest that long-term alterations in community measures probably were associated with factors related to runoff input. Nevertheless, the community composition remained reasonably rich and even. Landscape structure also appeared to influence community structure. Abundance of sensitive species remained significantly enhanced, even at sites of high RP, when forested reaches were present in upstream reaches. These probably provided a source of organisms for downstream recolonization and amelioration of effects at high RP.

Acidity is given in pH units. Acoustic signal strength is given in decibels (dB). Conductivity is given in microsiemens ftiS). Dissolved Oxygen (DO) is given in parts per million (ppm). Frequency of velocity measurement is given in hertz (Hz). Salinity is given in parts per thousand (ppt).Velocity coordinates are given in earth coordinates of magnetic east, north, and up.