Landscape environmental engineering design of urban waterfront green space

Waterfront green space is a very valuable natural resource of a city. Urban waterfront is a typical ecotone, located at the junction of aquatic ecosystem and terrestrial ecosystem, which has amphibious characteristics and shows ecological diversity under the influence of the two ecosystems [3]. It has the ecological functions of purifying air, purifying sewage, conserving water and improving microclimate environment. It is the ecological lung of the city and an important part of the urban ecological green corridor. ? Wise Leshan, benevolent people enjoy water? It is also an ideal place for citizens to rest, entertain and visit, and belongs to a natural ecosystem that is strongly disturbed by human activities.

At present, the transformation of waterfront green space in most cities still focuses on some basic functions of water system, such as flood control, shipping and irrigation. For the urban water system, measures such as cutting corners and straightening, hardening slope protection and building river banks are taken. Not enough consideration is given to citizens' recreational needs and landscape ecological functions. Therefore, how to maximize the recreational function and ecological function of waterfront green space and handle the contradiction between them is the primary problem to be considered in landscape design of waterfront green space. Taking the waterfront green space landscape design of Zhongfenjing as an example, this paper analyzes the principles and methods of urban waterfront green space landscape design.

1, project background and overview

Zhongfenjing, a tributary of Pudong New Area, is planned as a secondary river with no navigation requirements. The regulation reach of Zhongfenjing (Sanlintang Port to Chuanyanghe River) is located on the west side of Linsan World Expo home plot, and the river is close to Busan Road and the landscape of Linsan North Port along the line, with a length of about 2.3km, and the east side is about 15m from Busan Road, a secondary urban road, with the widest point of 56m. Except for Linsanbeigang section of Huaxia West Road, there is no revetment structure along the river, which is basically a natural slope. Weeds are overgrown in some areas on both sides of the river, and some banks collapse, which has caused serious water pollution and is in urgent need of reconstruction.

2. Design conception

The comprehensive improvement of the middle powder well is to meet the 20 10 World Expo as an opportunity to eliminate the black odor of the original river and return it to the public. The water is clear and the shore is green, the scenery is beautiful, and people and water are harmonious? Good ecological environment as the goal. ? Communicate water system, divert water, intercept pollution, build water features and improve ecology? Is it the river regulation in Pudong New Area? General policy? .

On the east side of Zhongfenjing is Linsan World Expo Home. What is the concept of Expo Park planning? Cities make life better? The concept that runs through it is: harmonious city. Therefore, this comprehensive landscape improvement design of Zhongfenjing still continues this concept:

Harmony between people: through humanized leisure, activities and the shaping of hydrophilic space, it provides a good platform for communication between people.

Harmony between man and nature: retain and utilize the original superior plant resources and reduce the damage to the original ecosystem; Abandon the excessive artificial greening form, absorb the essence of traditional gardening art, simulate nature to build a stable plant community, let plants grow naturally and happily, and create a more pleasant waterfront landscape of modern urban life.

Harmony between history and future: protect and restore the original historic sites (chastity archway) in green space, so that traditional culture can be inherited and developed.

3. Design principles

3. 1 Multifunctional consideration of flood control, ecology and landscape.

Because many cities are not strict with the management of industrial and domestic sewage, it is directly discharged into rivers within the city, which makes the original clear river water become? Black water river? , sewer. In addition to meeting the requirements of flood control function, comprehensive river regulation also includes the requirements of improving water quality, eliminating black odor, improving regional ecological environment, increasing recreational and landscape functions of waterfront green space, and enhancing the image of surrounding areas.

3.2 Highlight local charm and landscape personality.

It is of great significance to explore regional geography, culture and plant characteristics and express them through landscape techniques to improve the vitality, interest and cultural taste of urban waterfront green space. The environmental landscape design of Zhongfenjing waterfront green space should fully reflect the local characteristics of Shanghai, coastal cities and Pudong New Area. On the basis of using the original terrain, the landscape of city, road and green space is skillfully integrated together, and a modern waterfront green space with elegant environment, bright and fresh, rich landscape and suitable for sustainable development is created by simple gardening methods.

3.3 Plant landscaping to achieve sustainable development.

The ecological and landscape functions of urban waterfront green space are mainly realized by plants. Waterfront green space is a kind of landscape green space with rich natural landform characteristics. In the natural state, the riparian zone often shows the form of natural community with rich species and complex structure. Therefore, in the design, we should give priority to plant landscaping, based on the principles of landscape ecology, simulate the ecological community structure of natural rivers, give priority to native tree species, adhere to the principles of suitable site and suitable trees and biodiversity, increase landscape heterogeneity, create stable plant communities, restore the degraded natural ecological function of urban waterfront green space, and realize the sustainable development of landscape.

3.4 People-oriented, ecological priority

An important function of waterfront green space is to provide a comfortable, safe and pleasant hydrophilic, fitness, sightseeing and entertainment place for citizens, and to enhance interpersonal communication among citizens. With the continuous acceleration of social modernization, people's requirements for environmental quality are getting higher and higher. Another important ecological function of waterfront green space, that is, purifying air, purifying sewage, conserving water and improving microclimate environment, has been paid more and more attention. Therefore, what should the landscape design of waterfront green space adhere to? People-oriented, ecological priority? On the premise of giving consideration to social and ecological benefits. Emphasizing the protection and continuation of natural ecology, we can't achieve the goal of development at the expense of environmental quality. While meeting the needs of citizens' life and entertainment, we should minimize the interference of human activities on the organisms in the natural ecosystem of urban waterfront green space, maintain ecological balance, and then improve the environmental quality of the city, emphasizing the harmony between man and nature.

4. Design concept

4. 1 Landscape spatial sequence design

Waterfront green space is a linear landscape ecological corridor. Landscape spaces are connected in series by winding sightseeing trails, and multiple sightseeing space units are formed through virtual, open and closed space change design, so as to achieve the effect of changing the landscape space sequence:

1) Open land hydrophilic platform, square, sand and gravel floodplain

Setting up hydrophilic platforms in adjacent residential areas, taking Little Square as a landscape node, and setting up gravel beaches in areas with relatively few people to attract residents to play in the water is also a scenic spot to enjoy the scenery. The design spacing is about 300~400m, and the walking time is about 4~5 minutes (according to the walking speed).

2) Semi-open space of sparse forest, grassland and reflection.

Plant a mixed forest of Metasequoia glyptostroboides and Taxodium distichum with tall and straight branches at the water's edge, and control the canopy density between 0.4 and 0.6 to create a quiet space for rest and thinking, which has a certain sense of space closure; At the same time, waterfront plants will form reflections in the water in the direction of backlight. On the other hand, it seems that the reflection in the water is swaying, rippling and vague, which will give people unlimited room for daydreaming. The shadows are horizontal, the water is shallow, and the evening is fragrant. Artistic conception

3) Dense forests and tree-lined paths in confined spaces

Dense forests are formed through the community combination of trees and shrubs, and the canopy density is controlled above 0.7, which reduces the scope of human activities and provides excellent habitats for wild animals and insects. With the ups and downs of the terrain, the winding pace is arranged in the forest to form a winding path. Stroll through the forest and explore the winding and secluded places? Fanatical interest.

4.2 Environmental Protection and Ecological Design

Water quality is the key to the development of waterfront green space, and the development of urban waterfront green space needs to start with river cleaning and water purification. At present, the technology of using waterfront plants to control water pollution has made great progress in China. Wuxi Changguangxi National Urban Wetland Park is a successful example. It is planned to improve the water quality of Changguang stream system and its surrounding areas through low conservation and non-structural means, filter and discharge rainwater and floods, create a unique water system ecosystem and maintain sustainable development. In 2007, it won the highest honor national award of Canadian Landscape Architecture Society. Compared with ordinary sewage treatment plants, this method of purifying and improving water quality by absorbing, filtering and degrading pollutants in water through wetland plant system has the characteristics of low cost, long-term effect and multi-effect. Commonly used wetland plants are: reed, calamus, cattail, lotus flower, water chestnut, Alisma orientale, onion, Zizania latifolia, water lily, Solanum lyratum Thunb, Syzygium persicum and so on.

Plants and animals are the main factors to construct and restore the waterfront green space ecosystem. In this design, the original plant resources were deeply investigated, so as to minimize the damage to the original ecosystem and preserve and utilize the original superior plant resources.

After consulting the relevant water departments, build an ecological protection island near the mouth of Sanlintang Port? Bird island? It provides habitat for wild animals, with a width of 10~20m and an area of about 2300m2. At the same time, natural vegetation elements are introduced to simulate natural plant communities, and a complex ecological environment is constructed to meet the needs of birds, insects, such as food, shelter and hiding, and strive to create a beautiful landscape through the natural winding coastline and rich plant species. Water forest? . In the design process, we also consulted some experts about the main local birds, insect species and favorite plants, and designed some attractive birds, honey sources and aquatic plants to attract all kinds of birds and insects to inhabit. The selected plants are Cinnamomum camphora, Pu Shu, Mulberry, Cherry, Ligustrum lucidum, Calligonum mongolicum, Viburnum perfoliatum, Ilex cornutum, Sapium sebiferum, Pyracantha fortunei, Lycium barbarum, Loquat, Illicium verum, Pittosporum, Nandina domestica, Pomegranate, Elaeagnus Elaeagnus, Typha, Onion and so on.

5. Specific design

5. 1 revetment design

1) Section Form Design of Bank Protection

Adopt permeable natural gentle slope revetment. Due to the poor soil quality at present, in order to prevent the revetment from being washed away and collapsed by running water, concrete guide beams are designed to protect the revetment, and the top elevation is controlled below the constant water level line, which not only ensures the river bank to have a certain flood resistance, but also ensures the water exchange and adjustment between the river bank and the water body.

? It's not strange that there is no stone in the mountain, and the water is not clear without stone? Sprinkling some horticultural landscape stones along the river bank line and planting some aquatic and hygrophytic plants to soften the rigid revetment can also have a good landscape effect.

2) Optimization of horizontal line type of revetment

The planned river course is straight and lacks the aesthetic feeling of natural river course. On the one hand, the riverbank line is locally adjusted at the hydrophilic platform; On the other hand, through the intensive planting of waterside vegetation and the random placement of horticultural landscape stones, the straight and rigid riverbank line is weakened and softened, making it more natural and feminine.

5.2 Terrain design

Micro-terrain processing is adopted to increase the rhythm change of vertical vision. The sightseeing route changes with the topography. In order to ensure the comfort and safety of walking, the maximum longitudinal slope of the garden road is controlled within 8%, and the maximum slope of the waterfront revetment is controlled within 40%.

5.3 Hydrophilic Platform Design

The design of hydrophilic platform should not only meet people's hydrophilic needs, but also ensure safety. Because the water level changes greatly, several steps are designed near the water surface of the hydrophilic platform to adapt to the changes of different water levels, and humanized warning signs are set on the water surface.

6. Device design

6. 1 plant community design

Through the combination design of aquatic, wetland and woodland plant communities, the combination of arbor, shrub and grass forms a multi-level, cross-mosaic and species-rich ecological landscape belt, which enhances the heterogeneity of the landscape, improves the ability to resist external damage and interference, and is conducive to the restoration and formation of the ecosystem.

6.2 Design of Forest Edge Line and Canopy Line

Through the combination of different characteristic communities and the opening and closing of spaces, various small spaces with orderly advance and retreat, dense density and rich changes and beautiful forest edge lines are formed.

Waterfront greenbelt landscape is a zonal landscape belt. Through the combination of different forms, tall and short species and the ups and downs of terrain, a beautiful canopy line can be formed.

6.3 Seasonal Landscape Design

According to the GIS data of Shanghai green space, the ratio of evergreen trees to deciduous trees in various green spaces in Shanghai is about 1∶ 1, and the seasonal landscape is not rich enough. This design increases the proportion of deciduous trees, and the design ratio of evergreen trees and deciduous trees is 1:2. The autumn foliage tree Sapium sebiferum and seashore hibiscus are selected as characteristic tree species to create a characteristic autumn landscape, and at the same time, other seasonal landscapes are also taken into account, and some plants such as flower viewing, leaf viewing, fruit viewing, fragrant flowers, honey sources, birds attracting, etc. are rationally allocated to form a rich seasonal landscape.

6.4 Selection of Plant Varieties

Mainly choose native tree species, such as: Cinnamomum camphora, weeping willow, Metasequoia glyptostroboides, Sapium sebiferum, Pterocarya stenoptera, osmanthus fragrans, mosquito moth, fragrant bubble and Melia azedarach; At the same time, some new excellent seedlings, such as Gleditsia sinensis, seashore hibiscus, Miscanthus tenuifolia, Bullwhip, Apricot, Snake berry, etc. , also made an appropriate introduction.

Trees planted near the water must have a certain ability to resist water and moisture, and the main trees are weeping willows, Taxodium ascendens, Pterocarya stenoptera and Zelkova schneideriana. Strong water resistance; The aquatic and hygrophytic plants are selected from cicada, Zizania latifolia, Acorus calamus, Typha latifolia, Phyllostachys pubescens, Phyllostachys pubescens and Lysimachia edulis.

7. Conclusion

There are many factors to be considered in the landscape design of urban waterfront green space, involving a wide range of contents. It involves botany, ecology, biology, behavioral psychology, aesthetics, economics and other disciplines, and sometimes it needs to coordinate shipping, river regulation, vegetation and animal habitat protection, water purification, architecture and urban design. How to maximize the recreational and ecological functions of waterfront green space on the basis of satisfying some basic functions such as flood control, shipping and irrigation? People-oriented, ecological priority? There are still many problems that need to be explored, studied and improved in practice.