北京果雨花园：高密度校园里的绿洲 | 北京大学校园公益营建社
Harvesting Raingarden is located in the dormitory area of Peking University. This is a campus renovation project initiated, planned, designed, built, and operated by students. The garden was completed and put into use in October, 2019.
▲在用地极为紧张的校园中为学生提供了一个精心设计的开放空间，A new public place in a tight campus ©Jielan Zhong
Peking University is one of the oldest and most crowded university campuses in China. The southern part of the campus, in particular, houses 22,997 students in an area of less than 0.5 square kilometers. In order to provide enough space, the campus was constructed with high intensity, which has led to severe waterlogging and runoff pollution. The lawns between the buildings are not for human use and do little to reduce surface runoff.
▲遭受内涝困扰的校园，Waterlogged campus ©Liang Zeng
Waterlogging affects everyone’s life on campus. As future landscape architects, we are eager to apply what we have learned to help our own community. The idea quickly gained strong support from the school authorities. With their assistance, we selected a typical green space of 300㎡ in the dormitory area as the pilot. After 10 months of participatory design and discussion, a design scheme satisfying the interests of multiple parties was finally formed.
▲选取的设计场地，Selected design site ©Hao zhang, Kangfu Zhuo
▲设计场地毗邻的道路是最容易发生积水的路段，The design site is adjacent to a road that is most prone to water accumulation ©Hao zhang, Kangfu Zhuo
Less is more
The school authorities were hoping not to make too many changes, which happened to coincide with our thoughts: The goal of the design is to achieve the most abundant functions with the least amount of intervention on the site. First, we retained the heavily used sidewalks on both sides of the site, and second, we retained and utilized all the trees on the site. A small square of 5m by 5m is defined by the odd persimmon and walnut trees. The square divides the long and narrow green space into a larger and a smaller bioretention. We then reduced some of the retention ponds to provide parking space for bikes that used to take up the sidewalk.
▲方案生成，Design evolution ©Hao zhang, Kangfu Zhuo
▲方案轴测图，Axonometric ©Hao zhang, Kangfu Zhuo
The strategy of minimum intervention on the site not only meets the limitation of construction cost, but also makes it easier to find balance among different demands.Moreover, as a debut novel, the simpler the structure, the more able it is to cope with unexpected changes.
▲连续的清水混凝土墙强调了了空间的边界，Continuous fair-faced concrete walls highlight the boundaries of the space ©Hao zhang, Kangfu Zhuo
▲单一的草坪被丰富的植物群落所代替，The lawn with a single structure has been replaced by an abundant native vegetation community ©Jielan Zhong
There are many other similar green Spaces in the dormitory area that can be renovated in a similar way to alleviate waterlogging and improve the quality of the campus. The ultimate goal of the scheme is to provide reference experience for improving the macro campus environment.
▲自行车停车空间，Bicycle parking area ©Hao zhang, Kangfu Zhuo
The name of the garden, “Fruit rain”, came to us when we were finalising the plan on site.There are four fruit trees in the field. There are four fruit trees on the site. In August, the jujube fruit falls like raindrops. The fruit trees also inspired us to imagine how the garden could be used in the future.
▲姿态各异的果树，Trees in different posture ©Hao zhang, Kangfu Zhuo
The persimmon and walnut trees, both of which happened to have their crowns cut in half during construction in 2016, received the most attention for their peculiar pose. They stand opposite each other, highlighting the boundary of a small square of 5m by 5m. Among them, the persimmon tree with most of its canopy cut off was extremely mutilated. If you look at it from the east or west, its canopy looks very lush, like a pavilion. So we left an entrance under the tree so that pedestrians can turn into the site just under the canopy of the persimmon tree. As a sign of the entrance, the persimmon tree is given a symbolic meaning.
▲原本姿态反常的柿子树成为了场地入口的明显标识 The persimmon tree, which had an abnormal posture, became a striking sign of the entrance ©Hao zhang, Kangfu Zhuo
A place for a short stay
Three rounds of review were conducted to promote design proposal to accord with the requirements and suggestions from students. Students objected strongly to the placement of seats in the garden due to concerns about the noise caused by long stays and gatherings in front of the dormitory building. Therefore only informal seating is provided in the garden, such as the ledge of fair-faced concrete walls and recycled wooden piles.
▲未名湖边被风吹折的古树，The old tree blown off by the wind by the Weiming Lake ©Hao zhang, Kangfu Zhuo
Four months ago, a strong wind broke an old tree by the Weiming Lake. We left a few pieces of cut wooden stakes from the garden workers. Now these wooden stakes happen to be used as furniture in the garden. In addition, the ledge of the fair-faced concrete walls can also be used as an informal seat.
During one of the reviews, some students respectively proposed to set up a device for reading and a swing in the garden. For this reason, we provide a stainless steel swing with a sense of shelter on both sides for students to rest, relax and read.
▲木桩被重复利用作为座椅, The wooden stakes are reused as seats ©Kun Zhang
Rainwater collection and reuse
The garden can manage the runoff generated by the surrounding impervious surface of 572 square meters, reducing up to 16 cubic meters of rainwater for the dormitory area. The SWMM simulation results show that if the other green areas in the dormitory area are similarly transformed, a total of 47.8% of runoff flow can be reduced, which will greatly reduce the burden on municipal pipelines and effectively alleviate waterlogging.
▲SWMM模拟结果，The SWMM simulation results ©Hao zhang, Kangfu Zhuo
Due to the proximity of the building, a slow seepage structure is set on the bottom and sides of the bioretention to avoid the adverse effects of too much rainwater concentrated in a short time. When it rains, part of the rainwater directly infiltrates to supplement the groundwater, and the rainwater that is too late to seep is temporarily stored in the rainwater tank. When the rain has passed and the solar radiation reaches a certain level, the water pump will start. Temporary rainwater is returned to the ground through a solar pump to water the plants.
▲剖面图，Section ©Hao zhang, Kangfu Zhuo
▲依靠太阳能自动运行的雨水收集、利用和监控系统，Rainwater collection, utilization and monitoring system that runs automatically on solar energy ©Hao zhang, Kangfu Zhuo
The garden is also equipped with a monitoring system that can check the rainfall and the water level of the water tank on the mobile phone in real time, so as to monitor the running status of the water system at any time. And the collected data will provide guidance for similar projects on campus in the future.
▲存储的雨水在天晴时通过太阳能回到地面浇灌植物，The stored rainwater is returned to the ground through solar energy to water the plants ©Hao zhang, Kangfu Zhuo
The lawn with a single structure has been replaced by an abundant native vegetation community, providing a new stepping stone for hedgehogs, squirrels and sparrows in the campus. At the same time, it also creates a wilderness in a high-density built-up area.
▲丰富的本土植被，local species ©Hao zhang, Kangfu Zhuo
In this project, students are both users and designers, as well as clients and supervisors. The students led most of the work from the initiation of the project to the final completion of the garden. The construction was undertaken by Jinglin Group, which is enthusiastic about supporting students’ public welfare practices, and achieved a very high quality of completion. Despite the help of many people, this small project still encountered many difficulties in the construction process. The construction started from the summer vacation and lasted for 7 weeks. The team leader stayed on the construction site every day from 8 am to 6 pm to work with the workers, cooperating to solve various unexpected problems.
▲利用多余的水泥制作植物标本砖，Reuse excess cement to make Herbarium Bricks ©Qian Qiu
A series of workshops were organized to attract non-design students to participate. These continuous workshops have increased the level of public participation in the project and enabled the garden to gain widespread support from students.
▲住在附近的同学为花园留下的小诗, A poem left for the garden by a student who lived nearby ©Lizzy
▲总平面图，site plan ©Hao zhang, Kangfu Zhuo
▲平面图，plan ©Hao zhang, Kangfu Zhuo
项目设计 & 完成年份：2019年