Rehabilitation of Shengou Creek, a small, steep mountain stream in southwestern China that is prone to debris flows, started more than 30. years ago through an integrated program of engineering applications (check dams and guiding dikes), biological measures (reforestation), and social measures (reducing human disturbance). Small and medium-sized check dams and guiding dikes were constructed on key upper and middle sections of the creek to stabilize hillslopes and channel bed. Meanwhile, Leucaena leucocephala, a drought-tolerant, fast-growing, and highly adaptive plant species, was introduced to promote vegetation recovery in the watershed. The collective community structure of tree, shrub, and herb assemblages in the artificial L. leucocephala forest, which developed after 7. years, enhanced soil structure and drastically reduced soil erosion on hillslopes. Cultivation of steep land was strictly controlled in the basin, and some inhabitants were encouraged to move from upstream areas to downstream towns to reduce disturbance. These integrated measures reduced sediment supply from both hillslopes and upstream channels, preventing sediment-related hazards. The development of natural streambed resistance structures (mainly step-pool systems) and luxuriant riparian vegetation aided channel stability, diversity of stream habitat, and ecological maintenance in the creek. These findings are compared with Jiangjia and Xiaobaini Ravines, two adjacent non-rehabilitated debris-flow streams which have climate and geomorphologic conditions similar to Shengou Creek. Habitat diversity indices, taxa richness, biodiversity, and bio-community indices are much higher in Shengou Creek relative to Jiangjia and Xiaobaini Ravines, attesting to the effectiveness of rehabilitation measures.
Article talks about rehabilitation of a creek in China, which is debris prone. The issue is primarily anthropogenic in nature but it is driven also by climatic factors (i.e. the landslides/erosion risk is both anthropogenic and climatic). As a whole the intervention integrated a variety of engineering, biological, and social intervention. In areas subjected to serious gully erosion, small and medium-sized check dams, guiding dikes, and reforestation of fast-growing and effective erosion-controlling species were applied to control erosion and sediment transport, and to stabilize hillslopes and stream channels. In areas subjected to moderate soil erosion, hillslopes were modified by terracing fields and cultivation of plant species for soil and water conservation. In contrast, areas with gentle soil erosion were managed by closing hills to allow ecosystems to self-regenerate Initially engineering measures such as checkdams were applied, then reforestation with an introduced exotic species L leucocephala L. leucocephala was introduced to enhance the development of riparian vegetation along the creek. The introduced vegetation is characterized as a forest in the article. The application of rehabilitation measures over the past 30 years has stabilised the stream channel and the slope of Shengou Creek. Riparian vegetation has been well-established, sharply reducing soil erosion and sediment transport. erosion control was effective, and reduced sediment flow created channel bed scouring, they therefore developed step-pool systems to mitigate this. Riparian vegetation has developed well along the channels, enhancing valley floor roughness and local aesthetics (Fig. 6c and d). By 2005, the creek had been transformed from a debris flow gully into a recreational area with beautiful step-pool morphology and riparian forest, now becoming a forest park for local inhabitants.
|Climate change impacts||Effect of Nbs on CCI||Effect measures|
|Mudslides / Landslides||Positive||Same outcome measure for both soil erosion and mudslide reduction Sediment concentration (indicator of sediment supply from hillslopes/upstream channels); as an indicator of sediment related hazard/debris flow/landslide, and gully erosion|
|Soil erosion||Positive||Same outcome measure for both soil erosion and mudslide reduction Sediment concentration (indicator of sediment supply from hillslopes/upstream channels); as an indicator of sediment related hazard/debris flow/landslide, and gully erosion|
Shengou Creek the upper Yangtze River; Xiaojiang River basin; Yunnan–Guizhou Plateau