【作者】 张妤；

【导师】 张彦妮；

【作者基本信息】 东北林业大学 ， 园林植物与观赏园艺， 2021， 博士

【摘要】 作为城市雨洪管理研究的热点领域,城市各类开放空间的水适应性机制与优化可为城市生态文明建设提供参考依据,对于提升城市公共空间雨洪韧性、促进其水文生态功能的有效发挥具有重要价值。本研究以大连核心城区开放空间的水文结构特征为研究对象,依据公园、广场及场地、街区、其他共享空间(街道共享空间、绿道等)四种类型,综合运用格局指数方法、空间统计学方法、地形位指数方法对其三维空间形态与分布特征进行定量描述与分析;通过获取不同地形梯度典型空间下垫面植被截留与地表渗透性参数,模拟研究区城市地表径流过程,进而运用雨水径流调节服务供需测算途径对开放空间水适应性进行评估分析,揭示研究区开放空间水适应能力与主控因子,提出针对性优化建议,为城市开放空间低影响开发建设提供思路。主要研究结果如下:(1)研究区开放空间格局分布受城市空间结构、空间类型与属性、地形地貌影响明显,公园、其他共享空间为其主要景观类型。植被覆盖率及各类型空间分布尚不均衡,呈现出明显的聚集特征。依托自然山体与植物群落,开放空间的植被覆盖率自南向北逐渐减少。开放空间地形变化较大,公园和其他共享空间主要分布在中坡和陡坡,广场和街区主要分布于平地与缓坡。地形位指数最大值出现于公园,其他共享空间在低地形位上的分布优势最明显。开放空间的分布不均、北部自然植被的天然不足、地形的丰富多变增加了研究区开放空间雨水径流的流量、流速控制难度。(2)75%开放空间的土壤容重超过1.3g/cm3,土壤倾向于粘质土,空隙偏少,且土壤水分含量与持水量普遍偏低。四种开放空间土壤的稳渗率依次为公园>广场及各类场地>街区>其他共享空间,且均呈现出初始渗透率>平均渗透率>稳定渗透率的规律。公园、其他共享空间在不同地形位指数下的初始渗透率、平均渗透率还有稳定渗透率以及不同坡位下的初始渗透率都呈现出相同的变化规律。除地形以外,土壤容重、含水量、非毛管孔隙度也是影响开放空间土壤入渗性的主要因素,土壤容重、土壤含水量与土壤入渗速率呈负相关关系,土壤非毛管孔隙度与土壤入渗速率呈现正相关性。(3)不同降雨强度下开放空间径流调节服务的空间格局较为相似,变化集中于一些较小斑块。由城市东南部丘陵地带向西、北部推移,地势趋于平坦,开放空间密度下降,服务响应随之下降,水适应性逐步降低。在暴雨情境下,城市中部纵向廊道上的开放空间服务等级多有下降。城市公园与其他共享空间的径流调节服务响应均呈现由东向西逐渐下降趋势,城市广场及各类场地则呈现出北低南高的分布特征。街区的服务响应预算总量普遍偏低,雨水适应性较差。开放空间水适应性整体表现为东部好于西部,内陆好于沿海,城市公园与其他共享空间响应好于广场和各类街区。开放空间分布、地形、植被覆盖、排水设施是影响大连核心城区开放空间水适应性的主要因素。(4)针对上述研究结果,从空间分布、土壤入渗特性、径流调节服务3个方面提出了优化建议与管控策略。空间分布方面建议完善景观格局,均衡植被覆盖,顺应地形因子。结合土壤入渗生境特征建议构建主导促渗型、主导截留型两种适水型植被群落模式,并依据土壤地形位指数的入渗分区进行植被群落模式选择。综合径流调节服务评价,建议四种空间单元实施分类优化。水适应性较好区域,加强构筑山林空间水生态保护红线;水适应性适中区域,加强构建合理的水资源生态网络,水适应性较弱区域,弥补服务供给缺口,加强形成水生态补偿机制;水适应性差异较大区域,改善空间服务均衡与连通性,同时加强城市土壤改良、排水管网升级和低影响开发设施的构建。更多还原

【Abstract】 As a hotspot domain of urban stormwater management research,mechanism of the water adaptability and optimization of urban open space can provide reference for the construction of urban ecological civilization,which is of great value for improving the flood resilience of urban public space and promoting its hydrological and ecological functions.This paper takes the characteristics of hydrological structure of the core urban open space in Dalian as the research object.With the help of ArcGIS and eCognion9.0 analysis technology,the open space of the research area is identified on space and calculated on vegetation coverage ratio by using four types:parks,squares and sites,blocks,other shared spaces(street shared space,greenway,etc.),in combination with the DEM digital elevation in the study area to describe and analyze quantitatively its three-dimensional morphology and distributive property with the help of landscape layout index and spatial statistics.The parameters of vegetation interception and surface permeability can be obtained,based on the measurement of the soil of typical space underlying surfaces in different terrain gradient,then with the help of hydrological analysis model of Arc Hydrology to simulate the process of urban surface runoff in research area.With the help of supply and demand calculation of rainwater runoff regulation service,it can evaluate and analyze the water adaptability in open space,which reveals the water adaptability and main control factors of open space in the research area.Finally this paper puts forward corresponding optimization advice,which can provide ideas for the development and construction of low impact urban open space.The main results are as follows:(1)Parks and other shared spaces are the main landscape types of open space in the core urban area of Dalian.The overall connectivity and connexity of open space are high,but the patch uniformity is low and the distribution is unbalanced.With Olympic Square and People’s Square as a core area,the vegetation coverage ratio and spatial distribution of each type showed obvious aggregation characteristics,with a significant spatial positive correlation(P<0.01).Relying on the natural mountain and plant community,the open space and vegetation coverage ratio are high in the southwest and southeast,while the vegetation coverage ratio of the open space decreases gradually as it goes north.The terrain of open space changes greatly.The terrain of open space changes greatly,and parks and other shared spaces are mainly distributed on medium and steep slopes,while squares and blocks are mainly distributed on flat and gentle slopes.The highest landform bit index appears in the park,but other shared spaces had the most obvious distribution advantage in the low landform bit.The spatial structure,spatial type and attributes,topography and geomorphology are the important factors that affect the urban open spatial distribution pattern in research area.The uneven distribution of open space.the natural shortage of natural vegetation in the north and the richness of topography make it difficult to control the flow rate and velocity of rainwater runoff in the open space in the research area.(2)The bulk density of 75%open space is more than 1.3g/cm3 and the soil tends to be clay soil with less voids.Soil water content and water holding capacity in open space are generally low.which is bad for plant growth and hydrological regulation.The soil permeability rate of four open spaces are Parks>square and other kinds of sites>blocks>other shared spaces,and all of them show the rule of initial permeability>average permeability>stable permeability.The initial permeability,average permeability and stable permeability of parks and other shared spaces under different terrain indexes all show the law of low terrain level index,medium terrain index and high altitude shape index.The change law of initial permeability of parks and other shared spaces with different slope positions is the highest at the top of the slope,followed by the middle of the slope and the lowest at the bottom.In addition to topography,bulk density,water content and non-capillary porosity are also the main factors affecting soil infiltration in open space.Bulk density,water content and infiltration rate are negatively correlated,while non-capillary porosity and soil infiltration rate are positively correlated.(3)The spatial pattern of runoff regulation service in open space is similar under different rainfall intensity,and the changes concentrated in some smaller patches.The areas with the best service response were concentrated in the hilly areas with high density of vegetation cover in the southeast.In the west and north of the city,the density of open space decreases,the service response decreases,and the water adaptability decreases gradually.In the case of rainstorm,the service level of open space along the longitudinal corridors in the middle of the city is often reduced.The response of runoff regulation services in urban parks and other shared spaces is decreasing from east to west.The response levels of runoff regulation services in urban squares and various sites were lower in the north and higher in the south under the two rainfall scenarios.The service response level of the districts is high in the east and low in the central and western regions,the total service budget is generally low,and the adaptability of rainwater is poor.The overall water adaptability of open space is better in the east than in the west,better in the inland than in the coastal areas,and better in urban parks and other shared spaces than in squares and various blocks.The main factors influencing the water adaptability of Dalian open space are the open space distribution,topography,vegetation coverage and drainage facilities.From the general rainfall situation to the rainstorm situation,the threshold of vegetation coverage rate is increased from 42%to 58%to achieve the basic balance of runoff regulation supply and demand.With the increase of rainfall,the adverse drainage facilities around the space will also affect the performance of runoff regulation service and water adaptability in open space.(4)According to the above research results,the optimization suggestions and control strategies are put forward from three aspects:spatial distribution,soil infiltration characteristics and runoff regulation service.In terms of spatial distribution,it is suggested to improve landscape pattern,balance vegetation coverage and conform to terrain factors.Combined with the characteristics of soil infiltration habitat,it is suggested to construct two kinds of water-suitable vegetation community models:the dominant infiltration promoting type and the dominant retention type,then select the vegetation community model according to the infiltration zone of soil topographic potential index.According to the comprehensive evaluation of runoff regulation service,it is suggested that four kinds of spatial units should be classified and optimized.The water adaptability is better,and the red line of water ecological protection in mountain forest space should be strengthened.The area with moderate water adaptability should be strengthened to build a reasonable water resources ecological network.The weak water adaptability area should make up for the gap of service supply and strengthen the formation of water ecological compensation mechanism.In regions with large differences in water adaptability,the balance of spatial services and connectivity should be improved,while the construction of urban soil improvement,drainage network upgrading and low-impact development facilities should be strengthened.更多还原