Soil Characteristics and Management in an Urban Park in Hong Kong

3   threshold. With diminished porosity, transmission of air and water, storage of plant-available moisture, and root growth suffer. Chemically, the samples have an unnatural alkaline pH; inadequate organic matter, nitrogen, phosphorus, exchangeable cations; and limited cation exchange capacity. The results can help park-soil management, including the need to evaluate soil in planned park sites, salvage high-grade soil parcels, prevent construction damage, ameliorate structure by mechanical operations and suitable amendments, and replace site soil of very poor quality. Edaphic problems can be forestalled or solved by treating soil as an integral component of park planning and management based on scientific principles and methods.     

都市现代农业的环境影响及其治理——以成都市为例

以高投入、高消耗、高产出和高排放为特征的都市现代农业,对环境具有更大、更直接的影响,但只要选择恰当的模式,都市现代农业能够与环境实现协调发展。本文总结了成都市几种环境友好型现代农业发展模式,提出了促进环境与现代农业进一步协调的途径与对策,对全国的都市农业的发展有参考价值。     

城市第三产业环境管理的基本原则探讨

第三产业迅速发展所带来的环境问题日益成为影响区域环境质量及市民环境投诉的重要原因。文章分析了第三产业环境管理中存在的主要问题，初步探讨了第三产业环境管理的基本原则与污染控制途径。     

保定市区主要交通干道环境空气污染状况分析研究

利用保定市2013年7月份监测站点位大气环境监测统计数据,对保定市主要交通干道环境质量状况进行分析,结果表明,二氧化硫的日变化呈单峰分布,在中午12:00左右出现峰值,最低值出现在凌晨5:00。氮氧化物及一氧化碳的日变化呈现双峰型变化规律,早晨8:00左右出现第一个峰值,分别在下午15:00和17:00左右达到最低值,夜间19:00左右出现第二个峰值。说明交通干道两侧区域的二氧化硫、氮氧化物、一氧化碳的浓度变化与机动车流量之间存在一定的关系。     

城市生态支持系统的指标体系设计及实例分析

指出了城市生态支持系统对城市这一复合的人工生态系统可持续发展的重要性。运用层次分析法构建城市生态支持系统的指标体系，采用德尔菲法则确定其权重。以上海为例，设计了评价步骤与方法，对上海城市生态支持系统水平进行了定性、定量的研究分析，并总结了评价结果，进行了优劣分析。     

西藏拉萨市热岛效应及其影响因子分析

采用2001年、2004年以及2007年三年的EOS/MODIS遥感信息反演的地面温度以及多年常规气象观测资料,讨论了拉萨市热岛现象及其可能影响因子。结果表明:(1)热岛强度的年、季节变化呈现逐渐增强的趋势,其中,冬季的热岛强度最强,其次是春季,秋季和夏季的热岛效应较弱;高温区基本位于城市中心或者县城所在地及其周围,低温区主要集中在各县的郊区;近年来拉萨地区的城市高温区域逐渐扩大,有些高温中心可能向某些区域偏移;遥感资料所获取的地表温度与平均气温之间存在一定的正相关性。(2)无论是年变化,还是季节变化,热岛强度都与风速呈正相关,与日照时数呈负相关,与蒸发量的相关在夏季和冬季分别呈正相关、负相关的相反状况;地表温度与植被分布具有较好的负相关关系,即在城区存在较高的地表温度分布和较小的NDVI,过渡到郊区具有温度减小、NDVI增加的特征;随着城市化进程的加剧,建筑面积不断扩大,人类活动明显增加,排放至大气的人为热增加,这些因素都可能导致热岛强度的增强。     

上海臭氧及前体物变化特征与相关性研究

于2010年1~12月期间,在上海城区内采用在线连续观测,分析该地区近地臭氧与其前体物的季节变化规律及相关性,探讨了臭氧浓度与OX和NO₂光解速率之间的关系。结果表明,观测期间,上海地区O₃总超标天数为13天,超标率为3.56%。O₃浓度变化呈现明显的秋冬低、春夏高的季节变化。O₃浓度日变化规律呈典型单峰变化,O₃各前体物呈双峰形分布,冬季O₃与NO_X的相关性最强。对OX的贡献中,秋冬以NO₂为主,春夏以O₃为主;夜间以NO₂为主,白天以O₃为主。臭氧浓度与OX和NO₂光解速率变化规律基本一致。     

Regional water flows – Assessing opportunities for sustainable management

Sustainable water management may strongly benefit from an integrated approach. Additionally, an integrated urban water management policy considering the various urban water flows and the possible interactions between the water sector and the remaining urban activities can benefit if based on an urban metabolism based analysis. This article assesses water flows of Lisbon Metropolitan Area considering the conventional water supply system and wastewater treatment system flows and also the hydrological cycle flows, and proposes a global set of indicators to perform a benchmarking analysis of the 18 municipalities of the region. Results highlighted the heterogeneous nature of the Metropolitan area in terms of water management – either in terms of management entities (predominantly public or municipalized), water consumption (varying from 227.4 l/hab.day in Palmela to 402.7 l/hab.day in Seixal), wastewater treatment (10 out of 18 municipalities already undergo secondary or tertiary wastewater treatments), runoff indices (depending on the municipality's level of urbanization), among other. Through the output volumes it was also assessed the potential of the municipalities to reuse wastewater for potable or non-potable urban uses, as well as the potential to harvest and harness rainwater. The main constraints to an integrated water management were identified and some potential solutions were measured and proposed even though they need further assessment, particularly in a cost-benefit perspective.     

Factors affecting the variability of household water use in Melbourne,Australia

This study investigates the variability of household water use in Melbourne with the aim of improving the current understanding of factors affecting residential water use. This understanding is critical to predicting household water demand, particularly at an appropriate spatial and temporal resolution to support Integrated Urban Water Management based planning and to improve the understanding on how different household water demands respond to demand management strategies. The study used two sets of data each collected from 837 households under significantly different water use conditions in the years 2003 and 2011. Data from each household consist of the household characteristics and quarterly metre readings. Ordinary Least Square regression analysis followed by detailed analysis of each factor was used to identify key factors affecting household water use. The variables studied are household size, typology of dwelling, appliance efficiency, presence of children under 12 years, presence of children aged between 12 and 18 years, tenancy, dwelling age, presence of swimming pool, evaporative cooler, and dishwasher. All of them except presence of children aged between 12 and 18 years, tenancy and dwelling age were identified as variables that contribute to the variability of household water use in Melbourne. The study also found that the explanatory capacity of these variables increases with decreasing water use. This paper also discusses the significance of the explanatory variables, their impact and how they vary over the seasons and years. The variables found in this study can be used to inform improved prediction and modelling of residential water demand. The paper also explores other possible drivers to explain residential water use in light of the moderate explanatory capacity of the variables selected for this study thus, provides useful insights into future research into water demand modelling.     

Rainfall conditions and rainwater harvesting potential in the urban area of Khartoum

Runoff water management is among the inherent challenges which face the sustainability of the development of arid urban centers. These areas are particularly at risk from flooding due to rainfall concentration in few heavy showers. On the other hand, they are susceptible to drought. The capital of Sudan (Khartoum) stands as exemplary for these issues. Hence, this research study aims at investigating the potential of applying rainwater harvesting (RWH) in Khartoum City Center as a potential urban runoff management tool. Rapid urbanization coupled with the extension of impervious surfaces has intensified the heat island in Khartoum. Consequently, increased frequency of heat waves and dust storms during the dry summer and streets flooding during the rainy season have led to environmental, economical, and health problems. The study starts with exposing the rainfall behavior in Khartoum by investigating rainfall variability, number of raindays, distribution of rain over the season, probability of daily rainfall, maximum daily rainfall and deficit/surplus of rain through time. The daily rainfall data show that very strong falls of >30 mm occur almost once every wet season. Decreased intra- and inter-annual rainfall surpluses as well as increased rainfall concentration in the month of August have been taking place. The 30-year rainfall variability is calculated at decade interval since 1941. Increasing variability is revealed with 1981–2010 having coefficients of variation of 66.6% for the annual values and 108.8–118.0% for the wettest months (July–September). Under the aforementioned rainfall conditions, this paper then explores the potential of RWH in Khartoum City Center as an option for storm water management since the drainage system covers only 40% of the study area. The potential runoff from the 6.5 km² center area is computed using the United States Natural Resources Conservation Services method (US-NRCS), where a weighted Curve Number (CN) of 94% is found, confirming dominant imperviousness. Rainfall threshold for runoff generation is found to be 3.3 mm. A 24,000 m³ runoff generated from a 13.1 mm rainfall (with 80% probability and one year return period) equals the drainage system capacity. An extreme rainfall of 30 mm produces a runoff equivalent to fourfold the drainage capacity. It is suggested that the former and latter volumes mentioned above could be harvested by applying the rational method from 18% and 80% rooftops of the commercial and business district area, respectively. Based on the above results, six potential sites can be chosen for RWH with a total roof catchment area of 39,558 m² and potential rooftop RWH per unit area of 0.033 m³. These results reflect the RWH potential for effective urban runoff management and better water resources utilization. RWH would provide an alternative source of water to tackle the drought phenomenon.