Background The runoff-sediment relationship is the main indicator that reflects the hydrological cycle and soil erosion. In this study, we investigated the variation of flow-sediment relationship under the influence of ecological management in Jialu River Basin in typical hilly and gully loess region, aiming to provide some theoretical basis for the benefit evaluation of soil and water conservation and the prediction of soil and water loss.

Methods Based on Tyson polygon method and multiple hydrological methods (Mann-Kendall trend test, ordered clustering analysis, and double mass curve method), we analyzed the characteristics of runoff-sediment relationship before and after comprehensive management and its response to the management on the yearly and small time (event) scale in Jialu River Basin on the Loess Plateau.

Results 1972 was the transition year of runoff and sediment load in Jialu River Basin. Thus, the whole period was divided into two sub-periods, the baseline period (1957—1972) and the management period (1973—2014). Compared with the baseline period, the runoff-sediment relationship in the management period significantly changed at the yearly and event scale, and the sediment discharge at unit runoff depth was significantly declined. At event scale, the critical runoff depth of the basin was 6 mm. When the runoff depth was lower than this value, and the runoff-sediment relationship was discrete, otherwise, the runoff-sediment relationship tended to be stable. If rainfall amount was < 50 mm, rainfall intensity was < 4 mm/h or rainfall duration was >3 h, the runoff-sediment relationship in the management period changed significantly compared with the baseline period.

Conclusions The main reason for the change is the comprehensive management of soil and water conservation, and the significant reduction of the runoff and sediment yield of medium-low precipitation, medium-low rainfall intensity and medium-long rainfall duration.