Comparative assessment on functions of different revetments along the Guilin-Yangshuo section of Lijiang River southern China

The Lijiang River is a famous tourist resort in the Guangxi Zhuang Autonomous Region of China, as well as a major river for flood discharge. To ensure the navigation safety and protect the natural landscape of the Lijiang River, different types of revetments have been established along the Lijiang River since the end of 1980s, including engineering measure, plant measure and comprehensive measure. However, the status quo and effect of these revetments remain unclear, and there are few researches on functional assessment of riparian revetments. Given this situation, we carried out field ivestigation of revetments and established a functional assessment system on revetments in this study, in order to lay foundation on functional assessment on riparian revetments and provide theoretical basis and guidance for the construction and management of revetment restoration projects along the Lijiang River. In this research, the status of existing revetments along the Guilin-Yangshuo section of the Lijiang River was surveyed and classified systematically after thorough field investigation combined with image data. Then, engineering measure-masonry, engineering measure-gabion, plant measure and comprehensive measure, were selected as four representative revetment measures. After that, a functional assessment system on revetments was established using analytic hierarchy process which combined qualitative and quantitativeassessment. The final result of functional assessment on these four representative revetments was demonstrated in the comprehensive evaluation index. The assessment results showed that plant measure worked best, followed by comprehensive measure, engineering measure-gabion and, in the last place,engineering measure-sonry. Comparing two engineering measures, the gabion, which is more ecological, worked much better than the masonry. According to the above assessment result, and considering different safety requirements in different river sections, the optimal revetment measure and the ideal restoration proposals were put forward at the end of this paper. We suggest that the proportion of plant measures and comprehensive measures along the Lijiang River should be increased, which can stabilize the river bank, and improve its eco-environment as well.