A procedure for assessing the impacts of land-cover change on soil erosion at basin scale

Abstract

Accelerated soil erosion is an undesirable process that adversely affects the conservation of water and soil. This paper used a procedure linking the Revised Universal Soil Loss Equation (RUSLE) and geographic information system (GIS) to map the soil erosion level from 1990 to 2010 caused by land-cover change in the Dongjiang River basin, China. Results indicate that the significant land-cover change greatly impacted soil erosion. The overall soil erosion level of the basin belonged to Level II (mild erosion) but the erosion amount shown an uptrend. Erosion areas of Levels I and II occupied more than 90% and other levels (Levels III–VI) occupied less than 10% of the total area. Approximately 90.85% of the area maintained the original levels, 5.84% converted from lower levels to higher levels, and 3.32% converted from higher levels to lower levels. The erosion in the downstream regions was more serious than that in the central and upstream regions. Although soil erosion was mild as a whole in the study region, some local areas underwent intense erosion. The study demonstrated that linking RUSLE with GIS tools is an efficient procedure for mapping soil erosion levels at basin scale. The gradual deterioration condition caused by land-cover changes at present or in the future requires further study.

Quantitative Evaluation of the Impact of Climate Change and Human Activity on Runoff Change in the Dongjiang River Basin, China

“…The Dongjiang River basin is located northeast of the Pearl River basin between 113 • 52 -115 • 52 E and 22 • 38 -25 • 14 N. The river originates from Yajibo Mountain and flows into Canton Province from northeast to southwest, with a total catchment area of 27,040 km 2 [42], as shown in Figure 1. This basin has a subtropical climate with a mean annual precipitation of 1750 mm and a mean annual temperature of 21 • C. Vegetation in the Dongjiang River basin is generally satisfactory, except for some local areas.…”

“…A possible explanation is that although both the population and GDP exhibited significantly increasing trends in the two subregions (Table 8), less conversion from different land use types to urban areas occurred in the upstream area than in the downstream area ( Figure 2 and Table 2). Moreover, some biological measures, such as returning rice field to forest and pasture, were taken in the upstream and midstream areas [42], which could also help decrease the runoff coefficient.…”

“…As a major tributary of the Pearl River (southern China), the Dongjiang River basin has frequently experienced flooding and drought in recent years because of climate or land use change [41][42][43]. Several studies have shown the significantly change induced by climate in the Pearl River basin over the past 50 years, including a temperature increase of 0.38 • C/10a [44], suggesting that climate change can also alter runoff in Dongjiang River; the climate change projection has indicated the precipitation and temperature may show unstable change during 2021-2100 in southern China, which may also influence the Dongjiang River [45].…”

“…Several studies have shown the significantly change induced by climate in the Pearl River basin over the past 50 years, including a temperature increase of 0.38 • C/10a [44], suggesting that climate change can also alter runoff in Dongjiang River; the climate change projection has indicated the precipitation and temperature may show unstable change during 2021-2100 in southern China, which may also influence the Dongjiang River [45]. In addition, the intensity of human activity in this basin varies and exhibits a gradient development trend-a gradual increase from the upstream area to the downstream area [42,46]; that is, the impact of human activity in the downstream area is larger than those in the upstream and midstream areas, causing a variation in the effects of human activity on different river sections. However, the quantitative impact of climate change and human activity on runoff in the Dongjiang River basin has yet to be clearly determined and presents a challenging topic for the planning and management of water resources in a gradient development basin.…”

Land use and Land Cover change and its resultant erosion susceptible level: an appraisal using RUSLE and Logistic Regression in a tropical plateau basin of West Bengal, India

“…This result is validated by National forest report, India (http://fsi.nic.in/fores t-repor t-2005, 2017). Most of the positive changes are associated in degraded forest and settlement, while largest negative change occurs in double crop yield and barren land with laterite outcrop (154 km 2 ) due to drastically reducing soil fertility caused by human activities following Lai et al (2016) and Nasir and Selvakumar (2018). 4a, b).…”