北京中心城区内涝成因

城市化的发展改变了原始的自然水文循环系统,打破了水量的均衡而导致了城市内涝。本文梳理了应对雨水的基本模式,并总结出与城市规划相关的三方面主要致涝因素——城市土地利用、水系统和基础设施。以北京中心城区为案例,综合考虑城市用地变化过程,从城市基本汇水区单元的视角出发,分析城区内涝程度和上述三方面因素之间的关联规律。结果表明平均坡度、河网密度与城市内涝程度呈线性正相关;耕地比率、林地比率、荒地比率与城市内涝程度呈线性负相关;而不透水表面比率和建设用地比率与城市内涝程度呈指数正相关关系。     

Syracuse,sidewalks, and snow: the slippery realities of public space

This article addresses sidewalks as particular kinds of public spaces. Sidewalks of residential areas have been understudied; debates have tended to concentrate on pedestrian flows in commercial districts. By discussing the snowy sidewalks of Syracuse, New York, this article asks how sidewalks appear in law, and how responsibility for sidewalks is divided between governments and property owners. According to law and ordinances, sidewalks are responsibility of adjacent property owners. Unofficial monitoring has turned property owners’ sidewalk responsibilities away from questions of liability to questions of morality. Sidewalks evince a moral order, where questions concern not only pedestrian flows or laws, but also attitudes of others. A snowy sidewalk appears as a contested moral order, whose publicity is questionable because of the sidewalk’s reliance on private responsibility and policing. In the end, then, this article provides insights into how laws concerning public space are both maintained and questioned in everyday practices, and how the regulatory systems advance—or hinder—the publicity of public spaces like sidewalks.     

Economic Efficiency of Residential Water Conservation Programs in a Pennsylvania Public Water Utility

This study examines the economic efficiency of implementing a residential water conservation program in a small Pennsylvania public water utility. Local demographic data and results from similar programs elsewhere were used to estimate potential water conservation for three programs: rebates for low-flow toilets, rebates for high-efficiency washing machines, and in-home water audits. Future water supply and wastewater treatment demand were estimated. The net present value of constructing, operating, and maintaining new capacity infrastructure (water supply, water storage tanks, and wastewater treatment plant capacity), as well as the costs of the conservation programs, was calculated for a range of scenarios that included future demand growth, construction costs, interest rates, and levels of participation in the conservation programs. Results indicate that investing in residential water conservation would be cost-effective for a small number of scenarios that generally combine higher growth rates, higher interest rates, higher construction costs, and relatively modest public participation in conservation. The results are affected by the timing of necessary supply-side investments relative to the most significant water conservation gains, the relatively inexpensive local water supply costs, and the relatively high local wastewater treatment costs. Water conservation might be cost-effective for a wider range of conditions in communities facing scarce and expensive water supply options.     

支持向量机在供水方案综合评价中的应用研究

针对开始不能确定目标权重或隶属度的多方案综合评价的问题时,提出了一种支持向量机的学习算法实现多方案的综合评价。本文在电厂以中水作为水源的情况下,引入支持向量机算法,通过建立目标、综合属性的优化模型,再对建立的多种供水方案进行综合评价。计算结果表明,三种方案的综合评判值分别为:0.24、0.55和0.61,方案三为首选的供水方案,与实际首选方案和层次分析法确定的方案一样。将支持向量机算法应用于供水方案的选取,得到的综合效果评价是可行的。     

Identifying sustainability challenges on land and water uses: The case of Lake Ziway watershed,Ethiopia

This paper firstly analyzes the land use - land cover (LULC) in Lake Ziway watershed (Ethiopia) and quantifies the changing patterns from 1973 to 2014 using Landsat images. Secondly, the paper estimates sediment yields using the Soil and Water Assessment Tool (SWAT model). It also assesses and estimates water abstraction from Lake Ziway using survey data. The study shows that the conversions from woodlands into agricultural lands and settlement areas are the major detected LULC changes. Of the total area of the watershed, agricultural lands and settlement areas together increased from 57% in 1973 to 75% in 2014 at the expense of woodlands whose areas decreased from 26.16% to 6.63% in the study periods. The study also shows that water abstraction and sediment loads are increasing at Lake Ziway watershed. The major driving forces behind these LULC changes and the impacts on the lake natural condition are anthropogenic factors such as population growth, land policy changes and deforestation. Increasing demands for more land and water resources, i.e., land for settlements and cultivation, wood for fuel and charcoals, and water for irrigation and municipal water supply, are the underlying causes for the observed changes on the watershed resources. Thus, if the existing scenarios of human pressures are left neglected without management interventions, severe watershed degradations will continue to further affect the watershed's resources including the hydrology. Therefore, responsible government institutions should start mobilizing the local communities along with providing financial and material supports for watershed rehabilitation through afforestation and soil and water conservation activities. Additionally, the free-access practices for water use should be replaced by user-charge policy to regulate water abstractions in order to adequately sustain the water level of Lake Ziway and its feeder rivers. In this respect, this study provides firsthand information to policy makers and planners to put in place a comprehensive land and water use plan and regulations against the unruly human actions in the watershed before irreversible losses might happen to Lake Ziway and its watershed resources.     

广州市社区出行低碳指数格局及其影响因素的空间异质性

通过构建社区出行低碳指数（CTLCI）模型,对广州市社区出行低碳指数的空间格局及其差异特征进行了分析,并利用全局回归（OLS）模型和地理加权回归（GWR）模型对社区出行低碳指数的影响因素以及其间关系的空间异质性进行了研究。结果表明,广州市社区出行低碳指数由中心城区向外逐渐递增,呈明显的圈层结构。内圈层的社区出行低碳指数内部差异最小,中间过渡圈层的最大。社区人口密度对社区出行低碳指数的影响以正向作用为主,公共交通供给水平和路网密集程度对社区出行低碳指数的影响以负向作用为主,且它们的影响作用具有空间异质性。具体指出了在不同地域空间内社区人口密度、公共交通供给水平和路网密集程度对社区出行低碳指数在影响程度和作用方向上的差异,为减少广州城市交通碳排放、针对不同空间制定有效的低碳政策和构建低碳城市空间结构提供了科学依据。     

柴达木盆地沙漠公路设计流量公式研究

在中国水文分区中,沙漠地区一般被划分为非产流区,在公路设计中仅设置少量桥涵来满足路基、路面的排水要求,而不考虑洪峰流量,对非产流区也不提供设计流量公式。然而,在青海省柴达木盆地几条沙漠公路的实际运营中,却发现路基水毁频繁,经济损失严重。针对这种特殊水文现象,我们从设计理念、路基填料、暴雨、植被覆盖度等几个方面分析了水毁原因,发现暴雨是引发水毁的主要外因。因此将2012年最新的青海省公路系统柴达木区流量公式与两种小流域暴雨流量公式进行计算比较,通过分析计算偏差,对柴达木区流量公式进行了适度修正,最终得到能满足公路测量设计要求的柴达木盆地沙漠公路设计流量公式。     

On the frequency of lake-effect snowfall in the Catskill Mountains

Meltwater from snow that falls in the Catskill/Delaware watershed in the Catskill Mountains in south-central New York contributes to reservoirs that supply drinking water to approximately nine million people in and near New York City (NYC). Using the Interactive Multisensor Snow and Ice Mapping System (IMS) 4-km snow maps from the National Oceanic and Atmospheric Administration’s National Ice Center, we identified and tracked 28 lake-effect (LE) storms that deposited snow in the Catskills (2004–2017). These storms, which generally originated from Lake Ontario, but sometimes from Lake Erie, represent an underestimate of the number of LE storms that contribute snowfall to the Catskills snowpack because snowstorms are not visible on IMS maps when they travel over already-snow-covered terrain. Using satellite, meteorological (including NEXRAD and National Weather Service Cooperative Observer Program), and reanalysis data, we identified conditions that contributed to the LE snowstorms and mapped snow-cover extent (SCE) following the storms. We show that LE snow makes an important contribution to the Catskills snowpack because of the frequency of events, even though the total amount of each event may, on average, be small. The IMS 4-km maps tend to overestimate SCE compared to MODerate-resolution Imaging Spectroradiometer and Landsat snow maps. Climate change could impact LE storms and the distribution of rain versus snow in the Catskills, which may affect future reservoir operations in the NYC Water Supply System and winter recreation in the Catskills.     

Seasonal variation in stable oxygen and carbon isotope values recovered from modern lacustrine freshwater mollusks: paleoclimatological implications for sub-weekly temperature records

A fingernail clam (Sphaerium simile, Sphaeriidae) from Science Lake, a small watershed located in Allegany State Park, New York, USA and a zebra mussel (Dreissena polymorpha, Dreissenidae) from Keuka Lake, New York, the third largest Finger Lake of central New York, were selected to evaluate the applicability of using ¹⁸O_(CaCO3) and ¹³O_(CaCO3) values for sub-weekly climate records. Seasonal variation in ¹⁸O_(CaCO3) values was compared with predicted equilibrium values to test the hypothesis that lacustrine molluscs produce shell aragonite according to environmental variables. For the purpose of comparison, aragonite temperature-fractionation equations determined by Grossman& Ku (1986) and Patterson et al. (1993) were used. Sphaerium simile appears to produce ¹⁸O_(CaCO3) values predicted by Patterson et al. (1993), while Dreissena polymorpha produces ¹⁸O_(CaCO3) values in agreement with Grossman & Ku (1986). We attribute the difference to family-specific temperature-fractionation relationships. Because both types of mollusc record climate variables with a high degree of integrity, they should each serve as excellent paleoclimate proxies.The fingernail clam collected from a small watershed exhibits higher variation about the seasonal pattern than did the zebra mussel collected from a large watershed. This is attributed to the increased sensitivity of the small watershed to storm perturbation. Analysis of fossil molluscs from such watersheds might be useful in discerning paleo-storminess.     

珠江三角洲地区风暴潮灾害工程性适应的损益分析

在全球增暖及海平面上升背景下,风暴潮极端事件愈加严重,修筑海防工程是沿海地区应对和适应风暴潮灾害的主要工程性措施。以珠江三角洲为研究区,基于风暴潮历史灾害数据,分析了风暴潮增水与社会经济损失的关联性;提出了定量评价工程性适应风暴潮灾害的经济损益理论关系模型;推算了未来极端事件情景下,珠江三角洲海防工程建设的适应效果。结果表明,珠江三角洲地区风暴潮灾害的灾损率与增水呈显著正相关。海防工程建设高度在1.69~11.85 m内处于收益状态,其中5.22 m时收益最大。基于2030年、2050年以及2100年海平面上升叠加风暴潮情景,将海防工程设防标准定为应对2100年20年一遇风暴潮时的收益最大,标准定为应对2100年100年一遇风暴潮时收益最小。     

FROM EXCLUSIONARY COVENANT TO ETHNIC HYPERDIVERSITY IN JACKSON HEIGHTS,QUEENS*

ABSTRACT. When Edward MacDougall of the Queensboro Realty Company originally envisioned and developed Jackson Heights in Queens, New York in the early twentieth century, he intended it to be an exclusive suburban community for white, nonimmigrant Protestants within a close commute of Midtown Manhattan. He could not have anticipated the 1929 stock market crash, the subsequent real estate market collapse, or the change in immigration policies and patterns after the 19505. This case study examines how housing and public transportation infrastructure intended to prevent ethnic diversity laid the foundation for one of the most diverse middle‐class immigrant neighborhoods in the United States.     

西南山地滑坡灾害生态风险评价——以大理白族自治州为例

本文以云南省大理白族自治州为例,综合考量生态风险源、受体、暴露响应过程及生态终点,采用信息量模型评估滑坡灾害危险性,基于景观格局指数表征生态脆弱性,并将生态系统服务纳入风险损失的定量表征,定量评估流域滑坡灾害生态风险。结果表明：① 低于1800 m高程、15°~25°坡度、小于0.31植被覆盖指数等10方面因素构成了诱发大理州滑坡灾害的最佳信息量组合,全州普遍处于滑坡灾害危险性中高水平,且西北低、东南高;② 生态脆弱性高值区主要集中在红河流域南部、金沙江流域东南部、澜沧江流域中部;③ 低生态损失流域的水源涵养、粮食供给服务相对较差,生态损失中等流域的净初级生产、土壤保持服务优势明显,高生态损失流域则具有较强的粮食供给和水源涵养服务;④ 基于高中低3种生态风险等级和“高危险—低脆弱—低损失”等8种风险结构,全州367个小流域可划分出避让监测预警区、生态保护恢复区、避让保护兼顾区、自然适应调控区等4种风险防范类型区。     

北京地区坡面径流计算模型的比较研究

利用北京市西南山区房山蒲洼两个坡耕地小区30场降雨径流资料和密云石匣示范区休闲地试验小区13场降雨径流资料，对Chu修正的Mein-Larson-Green-Ampt(GAML)、Phillip、Horton和SCS径流曲线数法4种径流计算公式进行了对比。结果表明：GAML和Phillip计算结果的模型确定性系数较高，Horton入渗曲线和SCS曲线数的计算结果模型确定性系数偏低。根据模型参数的易获得性，建议在北京山区，在有降雨过程资料时，使用Chu修正的GAML入渗曲线进行径流计算；若无降雨过程资料可用SCS径流曲线数进行径计算。本研究结果可用于北京地区径流量预报和水土资源评价。     

柴达木盆地北缘水量增补对盐湖资源及生态环境的影响

柴达木盆地是我国盐湖资源集中分布区,受21世纪暖湿化气候和水量增补的影响,盆地多个盐湖呈现湖面扩张趋势,该过程开始影响盐湖资源离子含量和湖泊生态环境,也对湖区沿线公共基础设施造成一定影响。为了研究湖泊水量增补对盐湖资源及生态环境的影响,选取了柴北缘山前5个湖泊(苏干湖、德宗马海湖、巴仑马海湖、小柴旦湖和托素湖)作为研究对象,开展了2017~2021年湖泊扩张、典型盐湖矿化度和资源元素变化趋势以及对周边基础设施影响的研究。结果表明:1)资源型湖泊湖水淡化和资源品位下降;2)生态型湖泊周边植物群落发生变化(水生植物芦苇扩张、旱生植物白刺和梭梭衰退);3)淹没湖区房屋和旅游道路,危及周边的高速公路等公共基础设施。该研究结果不仅具有为柴达木盆地乃至青藏高原盐湖资源开采和生态环境治理提供科学依据的理论意义,而且具有为青海省基础设施保护和建设提供决策依据的现实意义。     

世界一流大学空间集聚对研发密集型企业空间布局的影响——以美国为例

以美国为例,运用矢量数据符号法、核密度估计,结合负二项回归模型,研究世界一流大学空间集聚对研发密集型企业空间布局的影响,得出以下结论：① 美国一流大学和研发密集型企业高等级集聚区主要有东北沿海大都市带、硅谷地区、芝加哥都市区和洛杉矶都市区,两者呈现高度的空间集聚性和空间匹配性。② 美国研发密集型企业偏向于选择与自身从事研发领域相关的一流学科空间集聚区进行布局。③ 美国一流大学和研发密集型企业的高值热点区集中在硅谷地区,呈半圆形辐射状,较高值热点区主要分布在东北沿海大都市带,呈带状辐射。④ 为寻求创新资源禀赋,获取知识溢出经济,共享创新基础设施,降低技术转移成本,获得创新集群优势,研发密集型企业优先选择一流大学集聚区进行空间布局。     

流域水资源丰富度评价的自组织神经网络模型

水资源丰富度评价是开展水文区划和水利化区划工作重要的科学依据[1] 。针对水资源丰富度与其影响因素之间复杂的非线性关系 ,该文提出应用自组织神经网络模型来评价流域水资源的丰富度 ,解决了在水文条件复杂的地区训练 (学习 )样本难以获得的难题。     

Tropical Storm Gamma and the Mosquitia of eastern Honduras: a little-known story from the 2005 hurricane season

The 2005 Atlantic hurricane season was unprecedented in terms of storm activity in the United States, Mexico, Central America and Caribbean. Given the impacts of hurricanes Katrina and Rita, the Honduran Mosquitia sparked little attention despite being hit by two hurricanes and a tropical storm in 2005. This article recounts the history of these storms in the Afro-Caribbean community of Batalla, drawing from public weather advisories and testimony of local residents obtained through participatory research. We contextualise this local history with results from the first paleotempestological study undertaken in the Mosquitia to shed light on long-term risk of catastrophic storms in the region and to demonstrate the value of integrating these two research approaches. Our findings contribute to recent ethnographic research on hazards by describing how a coastal people understand and respond to tropical cyclones and how landscape change influences the vulnerability of a coastal area. Although residents have not witnessed a storm as intense as those documented in the paleotempestological record, their knowledge and perceptions show how tropical cyclones can be disasters while leaving behind no sedimentary records. The paleotempestological evidence, however, reminds us that catastrophic hurricanes have struck the Mosquitia in the past and will do so again in the future. Understanding the interactions between contemporary human perceptions and responses and long-term hurricane risk provides insight for emergency managers and local stakeholders to better prepare for such a catastrophic event.     

中国农村基础设施建设投入不平衡性研究

中国经济发展已进入以工促农、以城带乡的新阶段。国家逐步确立了以人为本构建和谐社会的发展理念,提出了城乡统筹的区域发展战略和加快推进社会主义新农村建设工程。农村基础设施建设是保障农村生产生活的根本需要,也是满足农村居民精神文明与健康的需要,对中国农村居民生活空间扩展、资源共享和生存环境的优化等方面也有重大意义。文章利用基础设施建设不平衡指数模型,分析了中国各省区的农村基础设施建设水平相对于村庄人口、村庄面积、地区生产总值、社会固定资产投资和农村固定资产投资等因素之间的不平衡和滞后性。在此基础上文章还对这种不平衡性和滞后性进行了原因剖析,并借鉴国外农村基础设施的相关建设经验,提出推进中国农村基础设施建设的建议。     

A century of water supply expansion for ten U.S. cities

As population and water demand have grown, U.S. cities have responded by expanding their water supplies. This article traces this process over a century for ten U.S. cities. Most of the cities began by providing inexpensive local ground water. As the renewable supply capacity of local sources was exceeded, cities were forced to look further afield to obtain (or purchase) water (e.g., Marion, IL; Greensboro, NC), to access water from Federal projects (Tucson, AZ) or through international or interstate agreements (Waukesha, WI and Virginia Beach, VA), to combine with other localities in large joint projects (Greensboro, NC), or to use eminent domain to annex land for a new reservoir. This last approach has become increasingly limited by environmental statutes. The purchasing of water from other systems (Greensboro, NC) or water rights ( Tucson, AZ), aquifer storage and recovery systems (Tucson, AZ, Wichita, KS), and reclaiming wastewater for use in non-potable landscaping (Alamogordo, NM; Lubbock, TX; Tucson, AZ) are the more expensive options that cities are increasingly utilizing. Desalination represents the end of this process – expensive, but with a potential for enormous supply expansion that exceeds all likely demands. Demand management measures come into play only when the cost of securing additional water begins to exceed the cost of conservation or is induced by law. Reservoirs, well-fields, desalination plants, aquifer storage and recovery systems, and inter-basin water purchases have been abandoned because of the restrictions imposed by environmental laws or because less expensive demand-side options have been identified. The relationship between city size and its progression through these increasingly expensive water supply options is determined by local water resource endowments as determined by legal considerations and its physical geographic setting.     

基于空间公平理论的公共交通服务评价——以深圳市为例

使用空间无关的公平性衡量指数评价公交服务时,会忽视公交服务需求与供给的空间分布特征.为解决此问题,论文提出基于空间公平理论的公交服务评价框架,即通过构建综合基尼系数与莫兰指数的空间公平评价方法,实现整体尺度公交服务评价;通过对分析单元上相对需求与相对供给变量的匹配关系、空间差距进行分析,实现局部尺度公交服务评价,对整体...