Background Compared to the riparian zones of unregulated rivers, the riparian zone of the Three Gorges Reservoir (TGR) experiences relatively longer-duration artificial flooding and with high dynamic morphological changes. Reservoir riparian zone represents a hydrogeomorphological and biogeochemical ecotone between aquatic and terrestrial ecosystems and have been well recognized as a key area for maintaining ecosystem goods and services. However, this zone is ecologically fragile due to issues caused by frequent water level fluctuations. Little knowledge of successful management of environmental problems related to reservoirs riparian zone is currently available. Furthermore, there is lack of low-cost, high-benefit and easy-to-implement management technology.

Methods Soil erosion intensities along 12 transects in the reservoir riparian zone were continuously measured between 2008 and 2016 using erosion pins. The factors mainly influencing soil erosion were assessed using hydrological data, survey data, and long-term in situ soil erosion observation data. Based on authors' sci-tech achievements, combined with literatures, various ecological restoration technologies and site-specific modes were summarized.

Results Soil erosion modulus on riparian-zone slope was up to 94 887 t/(km²·a), 16 times on the counterpart of upland slope. Soil erosion intensity fortunately has been decreasing in recent years. The dominant driving force was wave erosion which was generated by wind and ship transportation, especially in mainstream riparian zone. The main measures for controlling soil erosion, stabilizing slope and restoring eco-system was to rebuild vegetation. Species selection for planting should be emphasized on the mechanisms attributing to adaptation of species to the extreme submergence stress, the growth recovery ability of species following release from submergence. In addition to focusing on improving the survival rate of plants and vegetation coverage, the effects of vegetation restoration on the bank stability, surface runoff regulation, sediment trapping, pollutant absorption, and plant diversity conservation should be considered. Six modes of ecological restoration at the TGR riparian zone were suggested:natural restoration, landscape vegetation ecological restoration, zonal soil consolidation and bank protection, ecological wetland, seasonal environment-friendly land utilization, and forage planting of ecological fishery.

Conclusions The TGR riparian zone is a new geomorphological unit, and its structure and function are still unstable. Soil erosion, landscape changing and ecological degrading have been all remarkable during the study period. Long-term monitoring and studies are needed to figure out the landscape processes and the ecosystem evolution.