喀斯特地区典型城市河流多自然特性评价体系研究

目前，针对喀斯特地区的多自然型河流治理研究较少，而喀斯特地区城市河流生态环境问题更为突出，生态环境更为敏感、更加脆弱，对此开展研究具有重要意义。本文在分析现有河流多自然特性评价体系、喀斯特地区河流特点的基础上，研究建立了喀斯特地区典型城市河流多自然特性评价体系，评价体系包含3个层次5大类19个评价指标，首次提出的5个重要评价指标权系数排名均在前10位，说明本体系更加完善，补充了以往研究中遗漏的重要评价指标。研究通过案例对比分析，表观多自然特性较好河段多自然特性量化评价分值明显高于表观多自然特性较差河段，进一步检验了评价指标体系的有效性、合理性、适用性。

Evaluation System of the Multiple Natural Features of the Typical Urban Rivers in Karst Areas

Guizhou Province is located in the core area of the southwest karst region, the most extensive karst landscape in China, and it is characterized by complex karst features. The karst outcrop area is 110,000 km2, accounting for 62% of the provincial land area and is distributed throughout the province. The fragile karst environment and complex ecosystem make the ecological problems of the rivers in karst areas more sensitive and unique. However, study related to managing the multiple types of river flowing through karst areas is not currently adequate. To better understand and protect rivers in karst areas, we developed an evaluation system for urban rivers in karst areas according to the multiple natural features as well as characteristics of the river. The system includes 3 layers (river basin, river channel and bank line), 5 index categories (physical, hydrodynamic, ecological, bank line, and river basin) and 19 evaluation indices (11 objective and 8 subjective). Forty experts ranked the importance of each index from 1 to 5 in a questionnaire survey and the weight coefficient for each index was based on survey results. Then five ranks of the evaluation system were proposed according to the weight coefficients. To verify the feasibility and effectiveness of the evaluation system, the system was applied to Nanming River, with typical Karst features. Two reaches were compared: (1) the reach from Huaxi Reservoir Dam to Sanjiangkou and (2) the reach from Sanjiangkou to Shuikousi. Results from the quantitative evaluation assign a much higher score for the reach from the dam to Sanjiangkou, with its many apparent natural features, than for the reach from Sanjiangkou to Shuikousi, the more urban reach. The verification study confirmed the effectiveness, rationality and applicability of the evaluation system. The five evaluation indices include water function conformance, water storage, conformance of bank line zone function, degree of river curvature and conformance of the main functional area, had weight coefficients ranking in the top 10. This comprehensive and quantitative evaluation system gives more complete information than previous evaluation indices. Our study provides scientific reference for multiple natural features and will allow formulation of management plans for other rivers with similar geomorphic features.