A distributed physically based model, soil and water assessment tool (SWAT), and a distributed conceptual model, distributed large basin runoff model (DLBRM), were selected to compare their applicability and performance in simulating daily runoff in the Heihe River watershed, the second-largest inland river (terminal lake) with a peak elevation of 5,584 m above sea level (asl) in arid northwest China. Both models have been calibrated against the observed daily runoff at the watershed outlet (Yingluoxia Hydrological Station) for the period of 1995–2004 and validated for the period of 2005–2009. Results show that both SWAT and DLBRM produced reasonable results in this study, and DLBRM performed better than SWAT. The difference in performance is mainly due to data constraints, different interpolation schemes, and spatial representations of landscape variations in the models. The tank storage-output principle used in DLBRM seems more suitable than the Soil Conservation Service curve number (SCS-CN) me...

Introduction: Arid area is an important base for human settlement, however, long and drastic human activities have altered the drainage patterns in the arid watersheds significantly, causing serious ecological consequences. This study, through a case study of the Minqin Basin, a microcosm of the artificial oases in the arid northwest China, used the multi-types of data to recover the spatial distribution of human settlement and drainage patterns during historical period and analyze the relationship between them over the past 2000 years. Outcomes: Before the Han Dynasty (121 BC), the utilization of water resources in the Minqin Basin was in the primitive stage and the drainage pattern maintained the natural state. From the Han (121 BC- 220) to the Wei-Jin Dynasties (220- 316), the utilization of water resources intensified unprecedentedly, but the natural shape of the river systems was still maintained. In the following 1,000 years or so, the drainage pattern was in the state of “following its own course” due to the small human population. In the Ming Dynasty (1368-1644), with the alteration of the main rivers, the water resource utilization increased obviously, but the human reclamations were mainly confined to the southern part of the basin. In the Qing Dynasty (1644-1911), the reclamation of the Liulin Lake area significantly changed the drainage patterns, resulted in the drastically northward expansion of human settlement. Since the foundation of the People’s Republic of China (PRC) in 1949, the artificial water system completely replaced the natural water system and intensified the ecological problems in the basin. Discussion: The changes over the past 2000 years show the drastic impacts of human activities on the alterations of the drainage patterns and related ecological problems in the arid Northwest China. Conclusion: Rehabilitation of such ecological impairments requires both ecological restoration projects and changes in human paradigm and behavior over multiple temporal and spatial scales.

The Upper Yangtze River Basin comprises a densely-populated agricultural region with mountainous and hilly landforms. Intensive cultivation has been extended onto steep hillslopes, which constitute the principal source area for sediment production. Soil conservation on sloping arable lands is thus of utmost priority for persisting sustainable agricultural production and maintaining sound ecosystem services. Although there have been many soil conservation techniques, either promoted by the government or adopted by local farmers, the practiced area was very limited relative to the total area affected by soil erosion. This paper attempts to introduce four popular soil conservation measures on sloping arable lands in this region to enhance a broader scale of implementation, including hedgerow buffers, level trenches, sloping terraces and limited downslope tillage. These practices, although developed from local farmers’ indigenous knowledge for productive purposes, have well conformed to our contemporary understanding of soil erosion processes on sloping landscape affected by human disturbances, were of sound suitability to regional manual tillage agriculture and more trade-off-efficient on rill prevention, runoff harvest and nutrient management.