The paper discusses using a model called SWMM to understand how Low Impact Development (LID) can help manage stormwater in a city. Scientists tested this method in a Chinese city called Tsingtao to see how well it worked in reducing runoff. By combining two ways of modeling LID in SWMM, they found that applying LID in specific areas can indeed decrease the amount of water flowing after rains. This research suggests that using LID techniques can be effective in controlling stormwater in different parts of a watershed.