Gully Consolidation and Highland Protection (GCHP) Project is a major soil and water conservation and land remediation project implemented in the Chinese Loess Plateau (CLP). As the connection between the mechanisms of erosion and practical applications for addressing it is not clear, the implementation of engineering measures to combat the problem has been insufficient to date. This study used field investigation and descriptive statistics, together with hydrological analysis modeling to gain an understanding of the impact of the Loess Plateau Highland Control Schemes on the evolution of the Dongzhi Plateau as the largest, most well-preserved, and the thickest loess deposit region in China. A remote sensing image was introduced to hydrological modeling to prove the analysis results of the Dongzhi Plateau. According to these investigations and analysis, four major schemes of gully head retrogressive erosion control were summarized and a comprehensive theory and technology based on a watershed were proposed. After hydrological analysis, the Dongzhi Plateau was divided into 1225 watersheds. It was found that GCHP should be implemented in the catchment area based on hydrological analysis to solve the problem of retrogressive erosion, and it is recommended that a scientific and rational drainage system should be designed based on the roads and pipe networks in the whole watershed area. Findings from this paper provide insights into the evolution of CLP and it can give a good suggestion on the future implementation of GHCP.

Studying the relationship between human activities and soil erosion on a regional scale is of great significance for macro-decision-making in soil erosion prevention and control. The entropy weight method and RUSLE model are used to analyze the spatiotemporal variation in human activity intensity (HAI) and soil erosion in the Weihe River Basin (WRB) from 2005 to 2020. Through geographic detectors and a four-quadrant model, the impact of various driving factors and the coupling degree of the human–land relationship are studied. The results showed: (1) During the past 15 years, the moderate, high, strong, and severe erosion areas in the WRB decreased by 9.88%, 35.89%, 45.17%, and 70.05%, respectively. The ratio of the historical sand transport modulus to the RUSLE model result is 0.83, indicating that the results obtained by the RUSLE model can be used for further analysis. (2) Slight and weak degrees account for 80% in the northwest region. The high and strong regions are mainly distributed in the Shaanxi section, accounting for 3% of the total basin. (3) The coupling between human activities and soil erosion is constantly strengthening, and the joint effect of pop and crop is the main reason for the slowdown and spatial differences in soil erosion. This indicates that the ecological environment became stable. These findings contribute by acting as references for soil and water conservation and management in the WRB to promote a harmonious relationship between humans and the environment.

The Gully Consolidation and Highland Protection (GCHP) project (such as for gully head landfills), a consideration of soil and water conservation measures, has been explored and developed continuously in recent decades in the Chinese Loess Plateau. Using high-precision images taken by drones to extract the topography of the basin, the changes in vegetation and land use were also analyzed. The observation of soil moisture in the critical gully head area of the GCHP was carried out. The results indicated that the critical zones of the GCHP project implementation include the gully head landfill, the gully, and the highland farming area. The soil moisture of the landfill area was 6.91% and 23.61% higher than that of the gully and farming area, respectively, with obvious spatial heterogeneity. The soil sand content in the gully head landfill area was higher than that in the gully area and the agricultural area of the plateau. The main reason for the high soil moisture in the gully head landfill area is that the terrain at the outlet is low, and it is at the lowest point of the whole basin. Analyzing the spatial distribution of soil moisture can point out the direction for the monitoring, prevention, and treatment of geological disasters, such as landslides and debris flow, induced by water erosion. This study will help to understand in detail the spatial heterogeneity and influencing factors of soil moisture under the implementation of the GCHP and improve the GCHP project management system.

The Gully Consolidation and Highland Protection (GCHP) project is crucial in preventing gully erosion in the Loess Plateau. However, there are new problems after the completion of the GCHP project, such as secondary disasters caused by sudden changes in water flow paths. To study the impact of different GCHP measures on runoff and sediment production, we conducted a series of scouring experiments using the similarity principle, taking Fengbao Gully, Xifeng District, Qingyang City, Gansu Province, as a prototype. Moreover, three scenarios in the GCHP project (landfill (LT), nondrained terraced (NDT), and terrace with a drainage system (DT)) are established. Seasonal rainfall simulation experiments are conducted with a constant slope. The results showed that during summer rainfall, the 10 min runoff depth of LT is 67.83~276.03% higher than that of NDT. However, in spring and autumn, the runoff depth of NDT is 4.12~39.84% higher than LT’s. The sediment yield of LT is 0.06–5.58 times higher than that of NDT and 1.91–25.58 times higher than that of DT. The sediment yield of NDT is 0.46–4.02 times higher than that of LT and 2.27–23.93 times higher than that of DT, indicating that, under the same conditions, the effect of slope replacement with terraces for GCHP is better than that of gully head landfill in reducing soil erosion and secondary geological disasters. Furthermore, imperfect terrace construction can result in increased sediment yield. This study provides a scientific basis for the maintenance and later management of GCHP and helps implement soil and water conservation measures in similar regions worldwide.

An accurate understanding of the relationship between reservoir construction and the dynamic change of groundwater level in downstream areas is of great significance for rational development and utilization of water resources. At present, the research on the interaction between surface water (SW) and groundwater (GW) mainly focuses on the interaction between river and GW. There are few studies on the impact of the reservoir construction on GW level in downstream loess irrigation area. Rainfall, evaporation and climate temperature have a great impact on W level, but the impact of reservoir construction on the GW level should not be ignored in the utilization of water resources. In this paper, a GW flow model under a natural boundary was established by numerical simulation. Taking Heihe Jinpen Reservoir in Heihe River watershed as the research object, the influence of the construction of a mountain reservoir on the dynamic change of GW level in the downstream loess region is studied. By comparing the GW level under the natural state without reservoir construction and the measured GW level after the reservoir was built, the variation of the GW depth in the loess area of the lower reaches in the Heihe River watershed is obtained. The results show that simulation accuracy of the interaction between SW and GW was reasonable; after the Heihe Jinpen Reservoir construction, the mean GW level decrease was about 6.05 m in the downstream loess irrigation area in Guanzhong Basin. It provides a method for the simulation and prediction of SW–GW conversion laws. This study is also of great significance to explore the change law of the water cycle and improve the utilization rate of water resources.