ZHANG Xiao-ming 1, CAO Wen-hong 1, WU Si-hong 2, QIN Wei 1 (1. State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100048, China; 2. National Center of Science and Technology Evaluation, Beijing 100081, China)

Abstract: Sediment delivery ratio (SDR) is a link to connect surface erosion and gully sediment delivery, which is also an indicator to demonstrate the capacity of sediment erosion and delivery of a certain basin. Hence, SDR is usually recognized as a helpful factor when evaluating sediment reduction effects due to soil and water conservation management and making policy-decision on ecological construction. Based on a systematic review on SDR studies at home and abroad during the last 50 years, this paper analyzed and discussed whether SDR has dependence characteristics on scale and its fractal characteristics or not. It was concluded that (1) the definition of SDR formula has embedded in the characteristic of scale, (2) SDR in different watersheds at home and abroad showed correlations with certain temporal and spatial scales, which means SDR is depended on its scale, (3) SDR could be quantitatively expressed and be scaled using fractal dimension under a certain temporal and spatial scale. The authors found that values of SDR and fractal dimension (D) at 1km 2 typical watershed unit were approximately equal to the SDR and D coefficients in corresponding scaling models. This paper pointed out that the calculation and study on SDR can't be correct without considering its scale dependence. It is a valid and useful approach to construct SDR scaling models by using fractal dimension, which could be an interesting research topic regarding on S DR scaling in the future.

Key words: sediment delivery ratio, soil erosion, sediment delivery, scale, typical watershed unit

Published in: Journal of Hydraulic Engineering, Vol. 44, No. 10, 2013