水保所知识产出(1956---)知识库

Gully land consolidation (GLC) is a slope-gully reclamation program that was implemented after “Grain for
Green” project on the Loess Plateau, China. Through the GLC project, the Chinese government planned to in-
crease the area of cropland by 337.80 km 2 from 2013 to 2017. To quantify the impact of GLC on runoff and
sediment transport, the coupled SWAT (Soil and Water Assessment Tool) model, which was integrated with a
process-based terrace algorithm, was employed in this research. The results showed that the improved SWAT
model was proven to be a powerful tool for detecting the effect of GLC on flow and sediment discharge. The effect
of GLC on flow and sediment loading was concentrated in the flooding period, its runoff interception efficiency
was 169,350 m 3 /(km 2 ⋅yr), and sediment trap efficiency was 3979 t/(km 2 ⋅yr), showing that it had good flow and
sediment reduction benefits. However, the GLC project drastically altered the water and sediment flux equilib-
rium, and excessive expansion was likely to lose parts of riparian-ecosystem functions of the downstream river. In
view of this, we integrated the improved SWAT (embedded in the terrace module), double-mass curve and Pettitt
test to identify the recommended ratio of GLC area to the total area in the Yanhe watershed. The results
demonstrated that if the reclaimed gully area accounted for 0.8% (61 km 2 ) of the total area (7608 km 2 ), the
runoff abruptly changed. Therefore, the reclaimed gully area should remain within 0.8% of the total area in the
Yanhe watershed, if so, GLC not only alleviates the contradiction between agricultural development and
ecological restoration, but also gives full play to its functions of reducing flood and restricting sediment
transport.