Forest and Farmland Conservation Effects of Oregon’s (USA) Land-Use Planning Program

Oregons land-use planning program is often cited as an exemplary approach to forest and farmland conservation, but analyses of its effectiveness are limited. This article examines Oregons land-use planning program using detailed spatial data describing building densities in western Oregon. An empirical model describes changes in building densities on forest and agricultural lands from 1974 to 1994, as a function of a gravity index of lands commuting distance to cities of various sizes, topographic characteristics, and zoning adopted under Oregons land-use planning program. The effectiveness of Oregons land-use planning program is evaluated based on the statistical significance of zoning variables and by computing estimated areas of forest and agricultural lands falling into undeveloped, low-density developed, and developed building density categories, with and without land-use zoning in effect. Results suggest that Oregons land-use planning program has provided a measurable degree of protection to forest and agricultural lands since its implementation.     

A Daily Time Series Analysis of StreamWater Phosphorus Concentrations Along an Urban to Forest Gradient

During a 1-year period, we sampled stream water total phosphorus (TP) concentrations daily and soluble reactive phosphorus (SRP) concentrations weekly in four Seattle area streams spanning a gradient of forested to urban-dominated land cover. The objective of this study was to develop time series models describing stream water phosphorus concentration dependence on seasonal variation in stream base flows, short-term flow fluctuations, antecedent flow conditions, and rainfall. Stream water SRP concentrations varied on average by ±18% or ±5.7 μg/L from one week to another, whereas TP varied ±48% or ±32.5 μg/L from one week to another. On average, SRP constituted about 47% of TP. Stream water SRP concentrations followed a simple sine-wave annual cycle with high concentrations during the low-flow summer period and low concentrations during the high-flow winter period in three of the four study sites. These trends are probably due to seasonal variation in the relative contributions of groundwater and subsurface flows to stream flow. In forested Issaquah Creek, SRP concentrations were relatively constant throughout the year except during the fall, when a major salmon spawning run occurred in the stream and SRP concentrations increased markedly. Stream water SRP concentrations were statistically unrelated to short-term flow fluctuations, antecedent flow conditions, or rainfall in each of the study streams. Stream water TP concentrations are highly variable and strongly influenced by short-term flow fluctuations. Each of the processes assessed had statistically significant correlations with TP concentrations, with seasonal base flow being the strongest, followed by antecedent flow conditions, short-term flow fluctuations, and rainfall. Times series models for each individual stream were able to predict ∼70% of the variability in the SRP annual cycle in three of the four streams (r² = 0.57–0.81), whereas individual TP models explained ∼50% of the annual cycle in all streams (r² = 0.39–0.59). Overall, time series models for SRP and TP dynamics explained 82% and 76% of the variability for these variables, respectively. Our results indicate that SRP, the most biologically available and therefore most important phosphorus fraction, has simpler and easier-to-predict seasonal and weekly dynamics.     

北京市生活垃圾中重金属元素的污染特性调查及对策

采用现场调研取样和理化分析检测的方法 ,对北京市城区垃圾中的重金属含量、主要污染元素和主要污染物进行测定 ,并在调查和分析的基础上 ,提出北京市城区垃圾中重金属污染的防治对策 ,为废弃物减量化、无害化与资源化提供了科学的依据和重要参考。     

浅谈我国城市环境综合整治的途径

本文从我国城市环境的现状出发，阐述了我国城市环境保护的历程，并在理论分析的基础上，提出了我国目前城市综合整治的基本途径。     

城市火灾扑救调度最佳路径分析

针对城市火灾扑救中的资源调度问题，综合考虑道路交通的各种迟滞因素，对通用的Dijkstra法进行修正，通过对两种方法计算结果对比表明，修正算法更为合理。在此基础上，结合受灾建筑本身的情况和消防力量分布状况，运用地理信息系统、图论、网络拓扑分析等领域的理论和方法，建立了优化调度的模型，实现调度优化决策模块。     

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.     

我国21世纪城市水灾风险及减灾对策

论述从50年代至20世纪末,我国城市水灾呈上升趋势,分析城市水灾的剧化与国土规划和管理、流域规划和管理、城市规划和管理上的人为失误有直接关系,指出我国21世纪城市水灾风险甚大,并提出相应的减灾对策．     

城市污水处理厂治理费用回归方程的建立

合理分析城市污水处理厂费用的组成 ,建立治理费用回归方程 ,是制定污水处理厂汇水区内排污收费标准的基础研究 ,并使城市污水集中控制及正常运转获取支持资金。     

The economics of green transition strategies for cities: Can low carbon,energy efficient development approaches be adapted to demand side urban water efficiency?

Cities are major contributors to global emissions, producers of waste and consumers of resources such as energy, water and food: implementing green development strategies is hence a core challenge of modern city-planning. The attention of research has been focusing on the development of energy efficient, low carbon strategies, yet city decision-makers need truly integrated approaches, as the one proposed by the water-energy-food Nexus. The purpose of our paper is to investigate whether it is possible to take one step in this direction by extending existing approaches to energy efficiency strategies to progressively include other priority resources, in particular water. To test this hypothesis we have taken a robust and well accepted methodology, the ELCC (Economics of Low Carbon development strategies for Cities) developed by SEI and CCCEP, and we have extended it to the case of demand side water efficiency strategies for cities. We have then applied the adapted ELCC framework to the case study of the domestic sector of the city of Bologna (Italy), identifying and prioritizing several efficiency measures. Measures were evaluated through their capital investment, annual values of savings, payback period and reduction in consumption, and then aggregated in different scenarios in order to highlight potential urban investments and to showcase a possible approach to the prioritization of demand side water efficiency measures. The results show that, with an upfront investment of € 17 million, a feasible subset of Bologna’s households could be equipped with five selected cost-effective measures, generating annual savings of € 10.2 million and reducing the total domestic water consumption of 34% by 2020 compared to the 2012 initial value. With additional € 28.5 million, households could be equipped with more costly appliances reaching an overall water reduction of 37% by 2020. Our findings confirm that it is possible to successfully extend current approaches to urban energy efficiency strategies to include demand side water efficiency, adding an important building block to the construction of an integrated Nexus-based approach to green development strategies at the city-level. We encourage further tests to confirm the robustness of the methodology.     

Wasting collaboration potential: A study in urban green space governance in a post-transition country

Most accounts of urban green space governance originate in cities where such initiatives have been successful. Meanwhile, there is too little information on cities where such initiatives develop with more difficulty. In order to overcome the problems that such cities face, their situations need to be studied more carefully to facilitate peer comparisons. This article provides an account of urban green space governance in three cities in Poland (Krakow, Lodz, Poznan), where environmental protection is still quite far down on the list of political priorities. With the use of a social network analysis we looked at the extent of relationships between different stakeholders and the roles of different actors within the network. The results indicate that the network's collaboration potential is barely used and that cross-sectoral collaboration is especially deficient. In particular, public institutions hold a relatively strong position and downplay the role of other actors. More collaboration is necessary and the potential bridging role of NGOs should be used to a larger extent. However, this requires more openness and trust within the network.