Effects of scale on interpretation and management of sediment and water quality : proceedings of an international symposium held at Boulder, Colorado, USA, during the XXI Assembly of the International Union of Geodesy and Geophysics, [July, 1995] / organized by the International Commission on Continental Erosion and the International Commission on Water Quality of the International Association of Hydrological Sciences; and sponsored by the World Meteorological Organization. Ed. by W. R. Osterkamp