# Research on Ecological Lawn Regulation and Storage System in Flight Area Based on Sponge Airport
## 1 Introduction  
The Civil Aviation Administration of China has formulated the \"Outline for Development of Green Aviation Manufacturing Industry\" (2023-2035) [1], which proposes the goals of green civil aviation construction, such as energy conservation, pollution reduction, carbon reduction and green expansion. A sponge airport [2, 3] is an airport stormwater management concept of a new generation under the background of the sponge city. The core of its construction is to absorb, store and purify water during rainfall and release the stored rainwater if necessary to improve the utilization rate of the airport's rainwater resources. A sponge airport is able to enhance the airport's ability to cope with extreme weather and achieve the comprehensive goals of green airport construction such as energy conservation, pollution reduction and rainwater resource utilization [4]. Newly built airports such as Beijing Daxing International Airport and Qingdao Jiaodong International Airport have applied the concept of the sponge airport to build new-type airports with holistic green rainwater management systems. The sewage treatment rate and the recycled water utilization rate of Beijing Daxing International Airport have reached 100% [5], while Qingdao Jiaodong International Airport has achieved the targets of a rainwater runoff control rate of 75% and a recycled water utilization rate of over 50% [6], which have played a leading demonstrative role and verified the feasibility and necessity of sponge airport construction. There are over 200 civil transport airports in China, which are classified into the five levels of 3C, 4C, 4D, 4E and 4F [7], from small to large. The 4E-level airports account for the largest proportion of the total number of the airports and have a large number of flights. Most of them are traditional airports without the rainwater management system of the sponge airport. Traditional airports adopt the treatment methods of \"rapid drainage ofrainwater\" and \"terminal centralization\", which mainly rely on drainage pipelines and pump stations, with single flood control and drainage measures [8]. Therefore, on the one hand, heavy rainfall places enormous pressure on the airport's drainage network. The rapid speed of surface rainwater runoff causes the problem of waterlogging in the flight area, and even the efficiency of the airport's operational safety could be affected by prolonged ponding durations in severe cases. On the other hand, the surfaces of runways in the airport flight area are contaminated with oil, rubber and chemical products such as de-icing waste liquid and de-oiling waste water, resulting in a high concentration of initial rainwater runoff pollution. If such rainwater is discharged directly into the municipal rainwater sewer system or the airport enclosure river without treatment, the problem of downstream water pollution will occur. The SWMM (stormwater management model) [9] is a dynamic precipitation runoff simulation model mainly used to simulate a single precipitation event or long-term water quantity and quality simulation in cities. This paper addresses the issues of runoff, water accumulation and pollution faced by traditional airport airfield drainage systems during heavy rainfall by proposing an improvement plan based on the sponge city concept. The core research question is how to effectively enhance the drainage capacity and water quality control of traditional airport airfields in response to increasingly frequent extreme rainfall events. To this end, the study selects a 4E-level airport in a city within Region III as the research object and puts forward the following scientific hypothesis: by introducing an ecological lawn storage system combined with gray infrastructure, the hydrological control and water quality of the airport airfield can be significantly improved. The study first conceptualizes the airport airfield drainage system and then constructs the ecological lawn storage system.