广东省东江干流江心洲监管等级评价系统构建与应用OA

Central bars are critical geomorphological and ecological features that contribute significantly to flood regulation,sediment retention,habitat provision,and river channel stability.However,they often represent weak points in routine river management due to their inaccessibility and dynamic nature.The main stream of the Dongjiang River in Guangdong Province hosts an exceptionally high density of central bars,0.9 per kilometer,far exceeding the provincial average of 0.19 per kilometer.While the majority of the 183 identified central bars remain in a near-natural state,a subset is subject to escalating pressures from unauthorized occupation,illegal sand mining,waste dumping,and unpermitted construction,collectively termed the"four chaos"in Chinese river governance.To address these challenges,this study established a scientifically grounded regulatory prioritization system using the analytic hierarchy process(AHP).Nine key indicators across three dimensions,natural conditions(i.e.,area under normal water level,vegetation coverage,and flood resilience),development intensity(i.e.,proportion of agricultural and built-up land,number of water-involved structures,and number of"four chaos"violations),and management requirements(i.e.,water quality class,soil erosion rate,and classification of drinking water source protection areas),were selected and integrated into a comprehensive evaluation framework,with Liyuzhou Island finally taken as a case study.Based on the regulatory demand index(ranging from 0 to 1),four categories of regulatory need were defined:"particularly strong"(>0.6),"strong"(0.2-0.6),"moderate"(0.1-0.2),and"relatively weak"(<0.1).These correspond to three regulatory tiers:Islands with"particularly strong"or"strong"demand were assigned to priority supervision,those with"moderate"demand to general supervision,and those with"relatively weak"demand to routine supervision.The resulting regulatory demand index ranged from 0.008 to 0.758 across the 183 central bars.Nine islands fell into the"particularly strong"or"strong"categories and thus required priority supervision;27 islands were classified as"moderate"and assigned to general supervision;the remaining 147 islands(80.3%)exhibited"relatively weak"demand and were recommended for routine supervision.Notably,Liyuzhou Island,the largest central bar in the main stream of Dongjiang River(69.86 hm2),scored the highest(0.758)due to extensive agricultural and residential development(91.3%land use),38"four chaos"violations,and its location within a Class II drinking water source protection zone,despite good vegetation cover(95.23%)and high flood resilience(above the 1%recurrence flood level).This study demonstrates that AHP provides a robust and transparent methodology for multi-criteria prioritization in riverine management.