The study measured the amount of direct runoff in Vientiane city to understand its hydrological condition. They used GIS mapping and the NRCS runoff method to estimate runoff from storm rainfall in the Mark-Hiao River watershed. By analyzing the data, they were able to determine the hydrologic condition of different areas in the city. The results showed that the method used was effective in representing surface flow networks and topography, and it accurately estimated the direct runoff in each sub-watershed during storm events.