Weiliu Wetland Park, China by YIFANG ECOSCAPE STUDIO

Restoration and revival of Wei River riparian zone

Project Specs

Location:

非常感谢 北京一方天地环境景观规划设计咨询有限公司 予gooood分享以下内容。Appreciation towards Yifang Ecoscape Studio for providing the following description:

 

源起:西咸城市化压力下的母亲河 | Background: the mother river under pressure

西汉文学家司马相如在著名的辞赋《上林赋》中写道:”荡荡乎八川分流,相背而异态”,描写了汉代长安上林苑的巨丽之美,自此有了”八水绕长安”的记叙。 八水之一的渭河是黄河的最大支流,也是西安和咸阳的母亲河。在西咸一体化城市扩展的背景下,渭河沿线的自然乡野河滩承受着被城市化的压力。城乡交错区的水环境不断恶化,乡野河滩迅速消失,河滩湿地被水泥护堤取代,人们对乡野大地的归属感越来越强烈。 渭柳湿地公园建设在渭河流经咸阳市渭城区河段存留不多的自然洪泛滩地之上,总长约3200m,宽约470m,占地面积约125hm2。本项目获得2018艾景国际园林景观规划设计奖唯一的卓越景观设计奖。

Wei River is not only one of the famous “Eight Rivers of Chang’an” described in Chinese historical literature and the biggest tributary of the Yellow River, but also the “mother river” of both Xi’an and Xianyang City. But as the urbanization progress of these two cities, the once natural riparian areas of Wei River have gradually been replaced by concrete dykes and decorative greenery planting. The constant degradation of the wild riverside landscape has also contributed to the loss of the sense of belonging, for the people who have lived in this rural area for generations.Weiliu Wetland Park was constructed on a section of Wei River’s riparian zone outside of Xianyang City, which was one of the few naturally flooded river sections that remained. It is approximately 3200m long and 470m wide, with a total area of 125ha.

▼项目地区位及上、下游现状,Images above: site location, existing conditions upstream and downstream

 

胁迫与问题:环境恶化、生态退化和消失的乡野生活 | Issues: water pollution, ecological degradation and the gradual loss of rural landscape

渭柳湿地公园所处的河段面临许多问题:场地上游河滩的自然原貌已被硬化水利工程取代,场地内的乡野河滩也面临着因城市化进程而破坏的压力;场地下游的河滩已被城市园艺化景观取代,河滩原有的物种丰富度和生物多样性下降,河道的自然生境系统严重退化;场地中多条城市雨污合流排水明渠经河滩排入渭河,在导致渭河水质恶化的同时严重污染了自然河滩的水环境(现场监测采样基本为劣五类);附近居民在滩地自发开垦了大量莲塘和菜地,反映出市民拥有强烈的对自然乡野和田园生活的诉求。

The project site had several major issues: The flood plain of the Wei river immediate upstream had been replaced by engineered concrete dykes, which put more flood pressure on the site. The adjacent area downstream had also been urbanized but with decorative planting, causing a major loss of local habitat and biodiversity. There were several roughly dug ditches across the site carrying stormwater run-off (and sometimes leaked sewage) from the city to the river, which has polluted not only the river itself but also the riparian aquatic environment (local sampling showed riparian water quality worse than Class V of the National Surface Water Standards). Finally, local residents had reclaimed a large area of the site for lotus ponds and vegetable farming, which showed a demand for the lost rural lifestyle.

▼实施前场地现状——饱经风霜的现状土堤、荒废的河滩地、雨污河流排水明渠和居民在河滩上开垦的菜地,
site before – existing earthen dyke, deserted riparian area, stormwater ditch and reclaimed vegetable farms

 

总体思路:构建综合服务的绿色基础设施 | Overall Strategy: Creating integrated Green Infrastructure

应对上述问题,本案以全面恢复和重建自然河滩的生态系统服务为首要目标,通过水安全、水环境、水生态、水休闲四大策略营建集洪水公园、海绵公园、城市公园于一体的城市综合绿色基础设施,实现适应性防洪、雨洪调蓄、废水净化再生、生物多样性修复、多样休闲和艺术化体验等多重服务价值。

To solve the issues described above, the comprehensive restoration and reconstruction of the local riparian ecosystem was the main goal for the project. A plan was developed to create urban Green Infrastructure through a series of strategies including adaptive flood control, stormwater management, water quality improvement, waste water reuse and biodiversity restoration, which would transform the site into an urban park that provides multiple values on environment and people.

▼总体设计思路,overall strategy

▼总平面图,the master plan

▼鸟瞰效果图,bird-eye view impression

▼恢复后的自然河滩湿地,reconstructed natural riparian wetland

 

弹性景观设计,适应洪水过程 | Creating resilient, flood adaptive landscape

气候变化引发的暴雨洪水频发已成为全球问题,渭河近年来的洪水压力也在不断增加。设计首先需要应对洪水问题。为了能在保证河道行洪安全的前提下恢复河滩的自然调蓄功能并合理利用河滩空间,设计利用原始地势条件,构建适应不同洪水位的弹性景观——将最易受洪水淹没(5年一遇水位以下)的浅滩作为洪水公园,将相对淹没风险较小的区域(10年一遇水位线以上)设为湿地净化区,最后将最为安全的区域(20年一遇水位线以上)作为田园休闲区。除了场地北面的100年一遇大堤外,场地内部的次级河堤均采用生态护堤的方式,结合扦插活体柳枝、抛石、石笼、植草缓坡等手段,既形成对洪水的保护和缓冲带,又兼顾生态修复和保护功能。

Frequent urban flooding due to climate change has become a global issue in recent years and Wei River has also suffered from increasing pressure from flooding, which is the project’s first priority. In order to restore the resilience of flood retention and utilize riparian spaces, an adaptive landscape was created based on the existing topography: the lowest areas were designed to be floodable natural wetlands, areas of lower flood risk were used for constructed wetlands and the highest areas on site were designated for recreational and leisure spaces. Bioengineering techniques were used on all flood control dykes inside the park except the outer dyke along the northern boundary (designed for one in a hundred year flood event). Techniques such as willow mattress revetment, riprap, gabions, and grassed slope were used for flood protection, biodiversity restoration and habitat protection.

▼5年一遇区域生态驳岸,grassed dykes for one in five-year flood protection

▼20年一遇生态护岸,riprap dykes for one in twenty-year flood protection

▼结合100年一遇大堤、利用现状高差形成阶梯式广场空间,
the outside dyke and associated level change was utilized to create tiered gathering and leisure spaces

 

利用原有土堤,构建渭柳绿廊 | Reusing the original dyke for green corridor

公园的中轴线由一条贯穿东西的休闲绿廊构成,绿廊在现状土堤的基础上改造,结合其形态对局部地形进行微调,并保留土堤两侧现有的柳树。公园建成后,原有的树木以及沿廊道补植的树木很快形成了河滩上的一道独特的风景线。

The main spine of the park was a green corridor that moved through the center of the park. It was built upon an existing earthen dyke flanked by willow trees. The trees were all retained and quickly became a unique scenic feature of the new park.

▼渭柳绿廊在现状土堤基础上改造而成,change existing earthen dyke into the central green corridor

▼树荫下的休闲廊道是贯穿公园东西的中轴线,retained existing trees flanking the central corridor make a unique scenic feature of the new park

 

污水净化,废水再生 | Purifying waste water for reusing

为了能在解决水污染问题的同时充分利用宝贵的水资源,公园在城市与渭河间构建起一道湿地净化缓冲带,将原直排渭河的雨污水引入污水厂,再对污水厂尾水(劣五类)通过人工湿地进行净化。净化后的再生水可达地表水III-IV类标准,满足公园绿化及农田灌溉,休闲亲水体验及回补河滩生态湿地等功能。人工湿地根据净化规模和目标进行设计,计算后确定以潜流湿地为主、表流湿地为辅的方案,并在流程中布置氧化塘以发挥调蓄缓冲、水体复氧以及向下级湿地均匀布水等功能。

In order to remove water pollutants and reuse waste water at the same time, a buffer belt of constructed wetlands was created between the city and the river. All polluted water from the drainage channels that ran through the site was firstly collected into WWTP. The constructed wetlands were designed for treating outlet water from a WWTP, and producing recycle water that meet Class III-IV standards using for landscape irrigation, the aquatic playground and finally directed to replenish the natural riparian wetlands. The design of the constructed wetlands was based on the post-treatment water quality targets of Class IV standards and used subsurface wetlands primarily with supplementary surface wetlands. Oxidation lagoons were also added to the process for flood buffering, reoxygenation and water distribution.

▼水资源净化及综合利用总体方案,a comprehensive water management plan

▼湿地组合提供了环境教育和休闲体验的机会,constructed wetlands also provide opportunities for environmental education and experiences

 

协助自然恢复力量 | Assisting natural recovery process

生态环境修复的关键在于为自然恢复过程提供一个启动的助力——在排除原有人为环境干扰后(如水污染、垃圾倾倒等),以营造多样化的栖息地类型为目标,在保留场地原有树木及野生芦苇的基础上,对河滩地形进行微调改造,同时适当补植乡土乔、灌木以及水生植物,从而修复和营造水生动物、两栖动物和水禽的繁衍、觅食和庇护场所。

The key for a successful habitat restoration is utilizing nature’s own regenerative power. After removing most of on-going human disturbances such as rubbish dumping and sand dredging, the project set its goal on recreating a diverse local habitat. Using existing trees and wild reed ponds as a foundation, the design applied minor earth shaping and careful replanting of local trees, shrubs and aquatic plants to restore shelters and habitats for aquatic life, amphibians and birds.

▼自然的力量——栖息地的恢复,the power of nature’s own ability to recover

▼通过微地形调整重塑河滩生态湿地,recreating natural riparian wetlands by minor earth shaping

▼栖息地的恢复带来了鸟类的回归,return of local birds after habitat reconstruction

 

回归乡野,体验自然 | Returning of rural life and natural experiences

在水环境修复和水生态建设的基础上,为了满足周边居民对乡野休闲和田园生活的需求,设计通过挖掘渭河水文化,以水为主线打造了水文化广场、亲水体验园、市民农园、乡野健身园等休闲游憩体验功能区,使这片河滩地成为市民回归自然、体验自然、追寻乡野生活的宜人之所。

In order to satisfy local demands for rural and natural activities, leisure areas such as civil squares, aquatic playgrounds, urban farms and rustic fitness zones were included in the park with a touch of local cultural elements. Using water as the main theme, the design gave nearby residents and park visitors plenty of opportunities to return and experience the restored natural riparian area.

▼孩子们在湿地亲水区玩耍,children were having fun in the aquatic playground

▼湿地是孩子们探索自然的最佳场所,wetlands were the best places for exploring nature

▼湿地亲水区每天吸引着众多市民前往休闲体验,many visitors were attracted by the wetlands everyday

▼跌水堰既能满足复氧功能又为湿地增加了许多体验乐趣,small dams re-oxygenates water for the wetland and at the same time became a play feature

▼秦腔文化广场为市民提供了理想的集散、休闲和活动场所, were larger spaces designed for gathering and resting within the park

 

艺术化的生态设计 | Creating artistic experience in nature

除自然生态景观外,公园的设计中亦结合了人文景观元素。生态湿地区中蓝色和橘色交相辉映的两条栈桥象征公园设计的两个核心理念——浅蓝向蓝紫的颜色过度象征水由浊转清的净化和蜕变,而黄色向红色的夜色变化则象征着秦渭文化的演变与传承。

One of the artistic elements was expressed through two colorful bridges in the wetland area. The two intertwining structures raised and lowered through the landscape, forming boardwalks, bridges and viewing platforms, which symbolized the integration of water and the local culture.

▼夜间的景观桥为公园增添了一分色彩,colorful bridges at night

▼象征自然和文化的两色栈桥交相辉映,intertwining bridges symbolizes the integration of water and local culture

▼景观桥和栈道相映成趣,design details of the bridge and boardwalk

 

最低成本、最大效益的可持续设计 | Low cost sustainable Landscape with high benefits

从项目的最初阶段开始,公园的设计就考虑了除环境外的社会和经济效益问题。结合投资预算和当地实际情况,通过低成本、低维护,低技术的技术与设计,获得环境、社会和经济的效益最大化。项目建成后,我们联合北京大学深圳研究院绿色基础设施研究所,开展环境绩效与社会绩效的综合评估工作,为公园的设计提升、管理维护、以及未来同类项目提供反馈。

公园建成一年后,园内各监测断面水质均达到国家III-IV类水标准,对比建设前雨污明渠的数据,COD、氨氮、总磷和总氮的削减率分别达到89.6%、98.4%、96.6%和79.5%,同时废水资源化的年回用量达到2.4×106立方米。据成本效益评估,公园平均建设成本为80元每平方米,仅为咸阳同类公园的三分之一。在环境效益方面,除上文提到的水环境提升外,公园内不同地区草本群落生物多样性Shannon-Wiener指数提升至1.57-1.91,乔木群落提升至2.11-2.33。在社会效益方面,在现场收到的462分有效市民问卷中,公园总体满意度为94%,其中对舒适性、亲近自然、儿童游乐和老人活动的满意度分别为90%、86%、77%和80%。在经济效益方面,公园建成后对增进了周边土地的增值。

Social and economic benefits were carefully considered at the very beginning of the project, which aimed at maximizing the project’s benefits while keeping the construction and maintenance costs down. After the completion of the project, a thorough evaluation process was carried out in conjunction of Beking University, in order to determine the environmental and social performances of the park and provide valuable experiences for similar projects in the future.

One year after the its completion, water quality monitoring spots across the park all reported results better than the Class III-IV standards. Comparing to water sample took from the original stormwater ditches on site before the construction of the park. The levels of COD, NH3-N, TP and TN in the water had shown a reduction of 89.6%, 98.4%, 96.6% and 79.5 respectively while the total quantity of water reused after treatment reached 2.4x106m3 per annum. Cost-benefit study showed the average construction cost for the park was RMB80 per m2, which was less than one third of similar local parks in Xianyang. As regarding the environmental benefits of the project, in addition to the improvements in water quality mentioned above, the average scores for different areas of the park on the Shannon-Widener Index (measuring local biodiversity) were improved to 1.57-1.91 for herbaceous plant community and 2.11-2.33 for trees community. The social benefits of the park were reflected in the results of a public survey: out of the 462 valid questionnaires received, the overall satisfaction rate for the new park was 94%, in which the satisfaction rates for comfort, experiences of nature, children’s recreation and leisure activities for the elderlies were 90%, 86%, 77% and 80% respectively. Lastly, nearby residents reported an increase in real-estate values of the adjacent areas after the park’s completion, though actual economic benefits of the park were less measurable at this stage.

▼项目建成后综合评估主要结果,summary of key findings from the evaluation

 

结语 | Conclusion

绿色基础设施是能够提供综合生态系统服务的多目标系统性工程。本案将生态防洪技术、人工湿地技术、栖息地修复技术统筹于河滩空间中,通过景观设计途径实现集洪泛漫滩、海绵湿地、城市公园于一体的渭柳湿地,成为生态文明建设在城乡绿色发展中的示范案例。

Green Infrastructure is a systematic approach for providing comprehensive eco-services with multiple benefits. The project integrated adaptive flood management, constructed wetland and habitat restoration techniques within the same space, making a floodable riparian zone, a stormwater management wetland and an urban park all into the one Weiliu Wetland Park, and in the process raised a good example for the building of ecological civilization on the background of sustainable rural-urban development process.

渭柳湿地公园——乡野河滩的水环境修复与再生
设计公司:北京一方天地环境景观规划设计咨询有限公司
位置:中国,陕西,咸阳
类型: 景观设计
标签:绿色基础设施、河道生态治理、综合性城市公园、城乡一体化
获奖:2018第八届艾景国际园林景观规划设计卓越景观设计奖
Weiliu Wetland Park – Restoration and revival of Wei River riparian zone
Design Firm: Yifang Ecoscape
Location: Xianyang, China
Type: Landscape
Tags: Green Infrastructure, River Restoration, Urban Park, Rural-Urban Development 
Award: Best of the Best Idea-King 2018 Award

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