The study looked at ways to reduce urban runoff and increase rainfall infiltration in Xi'an by analyzing different land use patterns. They found that the amount of runoff varied depending on whether the surface was permeable or impermeable, with factors like soil type and rainfall intensity playing a role. When there was more impermeable surface than permeable, runoff was higher. Increasing the depth of permeable surfaces helped reduce surface runoff, but had limited impact on runoff from intense storms.