Influence of Reconstruction and Extension of Karakoram Highway on Surface Water along the Highway

In order to analyse the influence of the reconstruction and extension of Karakoram Highway on the surface water environment,the water environment of roadside surface runoff and branch melt water from glacier in the typical construction section along Karakoram Highway are monitored and collected,and the watercourse compression condition caused by dumped waste rocky material in section K754+400―K788+000 is surveyed.The results indicate that(1) the suspended sediment concentration and ion concentration of surface runoff along Karakoram Highway are influenced very slightly by the reconstruction and extension of the highway over the construction period,the surface runoff along the highway is not influenced by the impact of petroleum and sewage pollution,the concentration of suspended sediment in roadside runoff increases rapidly in some sections,which is affected by the quality of branch melt water from glacier;(2) although 12% to 100% sections of watercourse are compressed by some waste rocky material dumped in flood plain(between right-of-way line and river bank) during the construction period,the cross-section of river is not diverted.The prevention measures to water environment in view of spatial location relation between highway and watercourse are given.