individual taxa lengths of macroinvertebrate taxa collected in the six European DRNs, together with associated environmental data collected during invertebrate sampling. Environmental and background variables include flow state, number of subsamples, sampled area, maximum, minimum, and mean wetted width, bankfull width at minimum and maximum wetted widths, pH, conductivity, temperature, dissolved oxygen (absolute concentration and % saturation), discharge, percentage of inorganic substrates, percentage cover of macrophytes and other organic substrates, mean water velocity, substrate embeddedness, maximum depth, and reach length.