Journal of Geographical Sciences ›› 2006, Vol. 16 ›› Issue (2): 242-250.doi: 10.1007/s11442-006-0213-0

• Climate and Environmental Change • Previous Articles     Next Articles

Estimating the minimum in-stream flow requirements via wetted perimeter method based on curvature and slope techniques

LIU Suxia1, MO Xingguo2, XIA Jun1, LIU Changming1, LIN Zhonghui2, MEN Baohui1, JI Lina1,3   

  1. 1. Key Lab. of Water Cycle &|Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research (IGSNRR), CAS, Beijing 100101, China|
    2. Key Lab of Ecological Net Observation and Modeling, IGSNRR, CAS, Beijing 100101, China|
    3. College of Water Conservancy and Architectural Engineering, Northwest A &|F University, Xi’an 712100, China
  • Received:2005-12-07 Revised:2006-02-12 Online:2006-06-25 Published:2006-06-25
  • Supported by:

    National Natural Science Foundation of China, No. 90211007; No.50279049; Knowledge Innovation Project of IGSNRR, CAS, No.CXIOG-A04-12; No.CX10G-E01-08

Abstract:

Under the assumptions of triangular cross section channel and uniform stable flow, an analytical solution of the minimum ecological in-stream flow requirement (MEIFR) is deduced. Based on the analytical solution, the uncertainty of the wetted perimeter method is analyzed by comparing the two techniques for the determination of the critical point on the relationship curve between wetted perimeter, P and discharge, Q. It is clearly shown that the results of MEIFR based on curvature technique (corresponding to the maximum curvature) and slope technique (slope being 1) are significantly different. On the P-Q curve, the slope of the critical point with the maximum curvature is 0.39 and the MEIFR varied prominently with the change of the slope threshold. This indicates that if a certain value of the slope threshold is not available for slope technique, curvature technique may be a better choice. By applying the analytical solution of MEIFR in the losing rivers of the Western Route South-to-North Water Transfer Project in China, the MEIFR value via curvature technique is 2.5%-23.7% of the multi-year average annual discharge, while that for slope technique is 11%-105.7%. General conclusions would rely on the more detailed research for all kinds of cross-sections.

Key words: uncertainty, wetted perimeter, minimum in-stream flow requirements, analytical solution, Western Route South-to-North Water Transfer Project in China