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Hangzhou Landscape Architecture Design Institute Co., Ltd.: Rivers and cities are often in a symbiotic relationship. Many cities have a “mother river” that bears the needs of urban residents for drinking water, agricultural irrigation and industrial development. For a long time, rivers have fed cities, but cities have not fed rivers back. On the contrary, the development and expansion of cities often brings pollution, encroachment of river channels and decline of ecological resources, resulting in frequent occurrence of problems such as soil erosion, rain and flood disasters and water resource crises.
▽湿地西向鸟瞰 Aerial view of west part
▽湿地东向鸟瞰 Aerial view of east part
In recent years, with the popularization of the concept of environmental protection, the contradiction between the city and the river has been gradually eased. Policy makers are also paying more and more attention to the protection of rivers, relinquishing the space that originally belonged to the river, and returning it to nature and citizens. This project is a typical case.
项目概况 Project Overview
The project is located along the Huangbai River in Yiling District, Yichang City. It is divided into two sections, located in Xiaping Village and Caijiahe Village, with a total area of about 154 hectares, of which the water area is about 35 hectares. The adjacent Nancaixia area is the core of the future northward expansion of Yichang city, and the city is closely related to the river.
▽场地现状遍布采石挖沙痕迹和农田菜地，极易造成水土流失和面源污染 The current situation of the site is all over the quarry sand excavation traces and vegetable fields, easy to cause soil erosion and non-point source pollution
The Huangbai River is a first-class tributary of the Yangtze River, with a total length of 162km. The downstream section flows through the urban area of Yichang. It undertakes the important task of supplying water to 2 million people and 1 million mu of farmland in the urban area of Yichang and Yidong. The total economic volume in the water supply area accounts for about 80% of the city is known as the “Mother River” of Yichang. The average slope of the Huangbai River is 3.76 ‰, and the mountains on both sides are steep, which is a typical mountain stream type river. Different from plain rivers, the former has obvious seasonal characteristics. In the flood season, a large amount of surface runoff can be collected in a short period of time, and the flow rate is large, and the sand carrying capacity and scouring capacity are strong; in the dry season, the water volume decreases sharply, and part of the riverbed is exposed.
▽主河道水流较湍急，特别汛期时易冲刷裸露土壤，造成水土流失 The main river flow is rapids, special flood season easy to wash bare soil, resulting in soil erosion
▽枯水期河床裸露 River bed exposed during dry season
The project area is the only two floodplain wetlands of the Huangbai River passing through the urban area of Yichang, where the river suddenly widens and plays an important role in regulating stormwater and providing habitats for living things. The status quo of the wetland retains a relatively primitive natural base, with large areas of tidal flats and ponds, and some natural forests grow well in some areas. The soil and rocks are exposed, the natural vegetation is destroyed, and there are a large number of artificial facilities such as sheds, abandoned factories, vegetable fields, etc., which have a great negative impact on the natural style and ecological value.
▽东侧鸟瞰可见对岸未修复区域挖沙痕迹明显，土石裸露 The east side of the bird’s eye view can be seen on the other side of the unrepaired area dredging sand traces, bare soil and stone
设计策略——生态优先，最小干预 Design Strategy – Ecology First, Minimal Intervention
The project is essentially an ecological restoration project, and its primary purpose is to protect and restore the floodplain wetlands of the Huangbai River flowing through the urban area of Yichang, so that it can better play its ecological function. Therefore, at the beginning of the design, the principle of putting ecological restoration first and “park” attributes second. That is to reduce the human damage and disturbance to the wetland, restore the vegetation, and create a suitable habitat for all kinds of wetland organisms, especially birds, so that they can live and reproduce here. The second is the needs of people, that is, to increase park facilities on this basis to meet the needs of public activities.
▽将挖沙遗留坑塘沟通串联，生态修复后形成海绵体系 The excavation of sand left by the pit and pond communication series, ecological restoration after the formation of sponge system
The minimal intervention strategy, for nature, refers to not disturbing the original area of the wetland as much as possible, such as retaining the existing native trees in the wetland as much as possible, and prioritizing the design if there is a conflict with the design. For people, it means that the boundaries of human activities should be demarcated, and the damaged wetlands should be restored.
总体设计——基于雨洪分析基础上的分级、梳理与建构Master plan – classification, sorting and construction based on stormwater analysis
Stormwater analysis – a prerequisite for master plan
Huangbai River is a mountain stream type river with huge water level difference between flood season and dry season, and the design range is located in the river channel delineated by the water conservancy department. Therefore, the rain and flood factor is the first consideration in the design. It is necessary to fully understand which areas may be submerged during the flood season and which are relatively safe, so as to provide a basis for the overall design and the layout of landscape facilities.
▽洪水位淹没范围综合分析-蔡家河段湿地 Comprehensive analysis of inundation range of flood level – Caijia River
▽洪水位淹没范围综合分析-下坪段湿地 Comprehensive analysis of flood level inundation range – Xiaping section
According to the hydrological data of each monitoring point measured by the water conservancy department, and the elevation data of the current surveying and mapping topographic map, the flood level inundation range of once in 5 years, once in 10 years, once in 20 years and once in 50 years can be delineated. Although the design elevation has been adjusted compared with the current topography, the overall impact is not large, and the subsequent analysis and layout are based on this basis.
▽蔡家河段湿地常水位与洪水位对比-等级约5年一遇，已将绝大部分河滩淹没，仅西岸部分高地露出水面Comparison of normal and flood water levels in Caijia Reach wetland
▽下坪段湿地常水位与洪水位对比-等级约5年一遇，主河道区域已大部分淹没，北侧河滩也部分淹没 Comparison of normal water level and flood water level in Xiaping section of wetland
Delineation of protection levels – avoiding excessive intervention
The wetland can be divided into three levels of protected areas according to the degree of protection and the intensity of human intervention, of which:
The first-class protected area covers the main channel of Huangbai River, and the existing features are completely preserved without intervention, and tourists are not allowed to enter.
The secondary protection zone mainly focuses on dredging the water system and restoring vegetation. Except for some elevated trestle bridges, there are no ground roads and activity venues, and there is less human intervention.
The third-level protected area is located at the outermost periphery and is the main activity area of the wetland park. In this area, natural methods are used to sort out the terrain, create green space, set up garden roads and activity venues, etc., and arrange a small number of service buildings, and the overall development intensity is low.
Facility layout – create a comfortable and safe activity space
Due to the requirements of the water conservancy department, there should be no facilities that affect flood discharge within the project scope. The design is based on the aforementioned rainwater analysis and combined with the flood assessment requirements to determine the construction scope, facilities and elevation control scope. First of all, a continuous elevated plank road system is set up, and the elevation of the surface layer is controlled above the flood level once in 20 years. The upper part is for tourists to walk through, and the lower part does not affect the flood flow.
▽栈桥面层高于20年一遇洪水位 The trestle surface is higher than the flood level in 20 years
▽高架栈桥穿梭于林间，汛期时不致淹没 Viaduct trestle shuttle between the forest, flood season is not submerged
The plank road can travel through the forest, or stand on the wetland water surface, giving visitors a rich experience of sightseeing and viewing. All levels of slow walking trails are set up on the ground, connecting the main tourist areas in series, and forming a three-dimensional cross network with the upper elevated plank road.
▽高架栈桥于林间穿梭，与地面道路立体交叉 Viaduct trestle shuttle between the forest, and the ground road three-dimensional intersection
▽栈道在林间穿梭，得益于原生林木的保留，形成高大的林冠线 The boardwalk shuttles through the forest, benefiting from the preservation of native trees, forming a tall canopy line
At the same time, combined with service buildings, bird watching houses, ecological parking lots, hydrophilic platforms and other facilities, the elevation of the first floor of the building is controlled above the 50-year flood level, and most of the main garden roads are above the 10-year flood level. Trails, hydrophilic platforms, etc. are all submersible facilities, which can be properly hydrophilic. The overall design strives to create an ecological wetland park that integrates wetland protection, viewing, popular science, and leisure on the basis of fully respecting the current situation.
▽林间的嵌草石板路 A grassy flagstone path through the woods
▽标高较低的园路保证了亲水效果，汛期可淹没 The lower elevation of the park road to ensure the hydrophilic effect, flood season can be submerged
▽生态停车场 Ecological parking lot
Sorting out the water system – communication and interconnection, creating a resilient landscape
The natural base around the main river channel of the base is relatively good, and it has not been damaged by human interference. There are naturally formed shoal sandbars and vegetation, and waterbirds can be seen inhabiting. This is completely preserved and designated as an ecological conservation area. The pits and ponds left by sand excavation outside the main channel are dredged, communicated and connected in series, so that the water systems of the pits and the main river can be connected with each other, and the wetland vegetation is restored to transform it into a series of rain gardens, which can be used in heavy rains. Undertake the surrounding catchment, slow down the discharge to the main river to a certain extent, and also reduce the flow when the upstream floods, and increase the rainwater storage capacity during the flood season. The original pit and pond revetment is relatively steep, and the design changes the shoreline and water depth to a certain extent, so that the water body shape is more natural, and at the same time, it ensures the safe water depth requirements near the shore.
▽河滩中央树丛远离游客活动区，有鸟类做窝栖息 The trees in the middle of the beach are far away from the tourist area, and there are birds nesting
▽利用现状凹地，形成多处小型雨水花园，承接周边汇水 Using the current sunken land, the formation of a number of small rain gardens, to undertake the surrounding catchment
▽挖沙遗留坑塘修复后变身为湿地的一处秘境 Excavation of sand left after the repair of a wetland turned into a secret environment
Plant Design – The Power of Native Vegetation
There are a lot of native vegetation in the current situation of the base, among which there are many tall trees with good growth, which are the backbone of maintaining biodiversity and creating landscape. The design requires that the existing trees be preserved as much as possible, especially the trees that reach a certain height and crown width should be 100% preserved. Due to the large scope of the site, the current plant information in the survey drawing is not accurate enough, and the design drawings cannot accurately avoid all native trees. Therefore, in the construction disclosure and construction process, it is particularly important for all parties to communicate on this issue in a timely and effective manner. When there is a conflict between the current arbor and the design of the road, plank road, etc., the design is given priority, so as to finally successfully make all the arbor with a diameter of more than 10cm at breast height. It has been completely preserved. In addition, according to the local climate characteristics and wetland project characteristics in Yichang, a variety of native plants and suitable wetland vegetation have been selected to improve the regional biodiversity.
▽植物风貌野趣，富有生机 The plants are wild and full of vitality
▽雨水花园种植多种耐水湿植物，生长繁茂 Rain garden planted a variety of water – resistant plants, luxuriant growth
▽原有挖沙遗留坑塘经过生态修复变身为湿地中最具生物多样性潜力的场所 The original pit left by sand-dredging has been transformed into a site with the greatest potential for biodiversity in wetlands through ecological restoration
After the project was launched, it has been included in the third batch of national pilot projects for ecological protection and restoration of mountains, rivers, forests, fields, lakes and grasses, and has successively become a demonstration project of ecological protection and restoration in Yichang City and Hubei Province. After the completion of the project, it has quickly become an important place for Yichang citizens to enjoy leisure outings, fitness entertainment and popular science awareness. You can hear the water gurgling, see fish swimming at the bottom of the pond, children playing in the forest, and egrets flying overhead. It is also the original intention of the design of this project.
▽湿地内部水系之间有高差，水流淙淙 There is a height difference between the internal water system of the wetland, and the water is murmuring
Project name: Yichang Huangbai River Wetland Park
Design: Hangzhou Landscape Architecture Design Institute Co., Ltd.
Design completion: June 2019
Project completion time: October 2021
Leader designer & Team: Zhang Qian, Yang Zhongliang, Wang Yu, Wan Changjiang, Ren zishuai, Nie wenbin, Bao Kan yuan, Gao Haifang, Jin Aixue, Huang Hao, Peng Changmin, Mao Jianli
Project location: Yiling District, Yichang City, Hubei Province
Project Area:154 ha
Photo credits : Zhang Qian, Wang Yu
Clients: Hubei Huangbai construction and Development Co., Ltd
“ 在减少对湿地的人为干预，恢复植被和生态的前提下，同时满足科普休闲观景的功能。 ”
审稿编辑 Ashley Jen
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