Relationship between Different Level Road Expansion and Soil Erosion Distribution: A Case Study of Lancang County, Southwest China

The effects of road construction and expansion on soil erosion distribution are large, and there exists great spatial variation of different level roads. How to quantitatively analyze the soil loss and their relationship is very important. Taking Lancang county as a case, we calculated the soil loss based on the universal soil loss equation (USLE) and GIS. Also, the average and sum soil loss of different level roads in series of buffers range were deduced. Results showed that: (1) The mean soil erosion modulus within 600 m had a decline trend except the first class road. The first class road had a wider effect on soil erosion since the drop appeared outside 600 m. (2) The sum amount of soil loss near the fourth class roads is the most and most obviously downtrend in buffer range.