Calculation and Verification of Peak Flood Flow in Small Watershed of ML-1 Line in Pakistan.

ML-1 line is the most important north-south railway trunk line in Pakistan and an important part of the China-Pakistan Economic Corridor. It was built earlier, and some small bridges and culverts cannot meet the normal flood discharge needs and need to be comprehensively upgraded. Since there are few available results in hydrologic computing in Pakistan, it is necessary to study and develop a small watershed hydrologic calculation method suitable for the region. Through mathematical statistical analysis of the annual maximum daily rainfall series data of three rainfall observation stations along the ML-1 line, the rainstorm parameters were obtained, and the storm peak discharge formula was used to calculate the design discharge of Bridges and culverts along the ML-1 line. In order to verify the reliability of the calculation results, the calculation formula of storm water runoff in railway department in China and the existing reasoning formula in Pakistan were used respectively. The calculation results were compared with the flow of typical watershed. The results show that the flow calculation results of the reasoning formula are reliable. Research results can provide references for the hydrological survey and design of other expansion projects in Pakistan. [ABSTRACT FROM AUTHOR]