Comprehensive analysis of waterlogging control and carbon emission reduction for optimal LID layout

Abstract Under the background of global climate change, flooding is causing devastating impacts on the balance of the regional water resources system. The campuses are typical built-up areas with high building density and are also disturbed by waterlogging. How to transform the campus rainwater system into sponge city reconstruction is the key problem to be solved. Based on the MIKE FLOOD platform, the urban waterlogging model is established, the causes of waterlogging are analyzed in this study. Low impact development (LID) measures are added according to the current situation. The carbon emission reduction capacity and economic benefit of each scenario are calculated and evaluated. The Analytic Hierarchy Process (AHP) is used to comprehensively evaluate the LID combination scenario to further explore a reasonable solution to mitigate urban waterlogging. The results show that the current rainwater pipe network built has a small pressure load on the campus, which cannot well respond to heavy rainfall conditions, resulting in a high risk of waterlogging in the campus. After setting up LID measures, the runoff control rate can be increased by 26.15-42.84%, and the waterlogging area above 15cm can be reduced by 72.87-100%. If the energy conservation and emission reduction benefits and costs are considered at the same time, the layout scenario of 9% bioretention facility +3% green roof+3% permeable pavement can achieve the best benefits. The research can provide a reference for planning and reconstruction of ‘sponge campus’ and old residential areas.