城市高强度耗水的机理与模型研究

The urban area covers 3% of land area in the world, while it used 30% the water supply. The water consumed in urban area was significantly higher than that in rural area. The intensity of the water consumption was 1480mm/a in Beijing cityzone, and up to 3000mm/a in some factory in Tianjin, according to the water balance analysis. These values are greatly exceed the local potential evaporation, which does not accord with the principle of hydrology. Where did the water go? The hydrologist had two explanations. The first one was that some of the water contained in the industrial products had been transported out of the cityzone. The second one was that the water had infiltrated down to recharge the ground water. Neither of the explanation could prefectly reveal the abnormal phenonmena as there were some confilits. The first explanation must face the fact that quantities of watery agricultural products had been transported into the city, which could conteract the industrial products transported out. The second one had to face the fact that the ground water level was steady declining, which was contray to the explanation that the water had infiltrated down to the ground water. The research work will focused on revealing the mechanlism of high water consumption in urban area, based on hydrological observation and water balance test on community and factory scale. The campus of Tsinghua University will be selected as typical community, and Tianjin Blue Star Petrochemical Plant will be selected as typical facory, for test and exprimental analysis. Based on the test and exprimental analysis, the concrete jungle in urban area was taken as lively organisms, which had cycical water consumption behavior. The mathematical models were estabilished for calculating different kinds of evaporation and transipiration in the urban area, with consideration of water resourses both from rainfall and aritficial water supply. The mathematical models were integrated into a platform, which could simulate the water consumption in urban areas with complicated underlying surface. The integrated model was calibrated and validated by regional water balance test and community hydrological experiment. The integrated model was applied in the typical community of the cityzone to simulate the water cycling. The evaporation from rivers,lakes, bathrooms, wet floor, wet clothes, kitchen,and the evapotransipiration from urban greenland were calculated. All the water transformed from liquid to vapor had been estimated and countered, including some trivial water use. Finally, the phenomenon of high water consumption in urban area had been analyzed and the scientific conclusion was drawn.

城市面积约占全球陆地面积的3％，其用水量却占总供水量的30％以上，城市耗水强度远高于郊区和农村。水平衡测算表明北京中心城区耗水强度约为1480mm/a，天津工厂区局部的耗水强度甚至高达3000mm/a，大大超越了当地的水面蒸发能力。如果说这些水是通过常规蒸发的形式耗散到空气中的，则有悖于水文学蒸发原理。本研究拟通过对典型小区和典型工厂的剖析和观测实验，揭示城市高强度耗水的内在机理。基于机理认识，应用类比法和仿生学原理，将"钢筋混凝土森林"抽象"活化"成具有"生命"、"细胞"和"周期性耗水行为"的有机体，考虑城市水循环的"双源"特性，构建城市分项耗水计算的理论公式，并集成建立具有物理机制的城市耗水定量计算模型。通过区域水平衡校验和小区实验观测值校验两种方法对模型进行率定和验证。在典型城市小区观测、模拟和典型工厂水平衡测试的基础上，对城市耗水超过当地水面蒸发能力的超常规现象作出科学合理的解释。

《城市高强度耗水的机理与模型研究》项目严格执行年度研究计划，围绕“城市高强度耗水的内在机理”、“城市单元耗水定量计算模型”两项目标进行攻坚，在理论、机理、模型等方面取得了一系列创新成果。理论方面：建立了城市耗水平衡的框架体系，明确了城市耗水的物理意义，创新提出了建筑体耗水的“仿生学”理论，构建了耦合自然-社会双源水量输入的城市水平衡范式。机理方面：解析了城市耗水过程，揭示了城市建筑体内部的耗水原理以及城市人工热源、人工干扰因素对城市耗水的增强作用机理，建立了建筑体耗水强度与建筑体功能、建筑密度等的多元数量关系，科学分析并定量解释了城市高耗水现象，突破了城市耗水的黑箱模式。模型方面：构建了城市耗水计算模型和城市生活用水指标计算模型等，建立了城市不同下垫面的耗水计算函数，解决了排水观测、土壤入渗量模拟、人工热源影响评估、人工干扰定量描述、城市水文单元动态划分等一系列关键难题，实现了城市复杂下垫面耗水的分布式定量模拟。城市耗水理论与模型在北京市主城区进行了实证应用，结果显示城市区域耗水强度高于郊区约400mm/a，个别建筑和人口密度高的区域耗水强度接近甚至超过当地水面蒸发能力；而传统水文模型、遥感反演模型对城市蒸散发的计算结果明显偏小，分析原因主要是以往研究忽略城市人工用水产生的蒸发耗散。本项目的研究成果及发现对正确评估城市化对水资源的影响，科学计算城市水资源消耗量等具有重大的科学意义。项目成果共发表论文21篇，SCI收录8篇，EI收录6篇；出版专著4部；申请专利8项；培养研究生10名（博士后1名，博士3名，硕士6名）。项目培育了1名国家自然科学基金“优青”，1名国家“万人计划”青年拔尖人才。项目成果支撑国家科技进步一等奖1项、全球人居环境奖一项（排名5）、中国青年科技奖1项、省部级一等奖1项，二等奖3项。综上所述，本项目全面超额完成了计划书规定的各项任务和指标。