The Impact of the Water Framework Directive on Catchment- Management Planning in the British Isles (Abridged)

The water framework Directive is proposed as a mechanism for applying river-basin management across the European Union. Proposals for River-Basin Management Plans might have an impact on the present system of Local Environment Agency Plans and on schemes which are used in the British Isles to provide river management on a catchment basis. For this study, representatives from the Environment Agency, Scottish Environmental Protection Agency and European Parliament advisors were interviewed. In addition, Local Environment Agency Plans were assessed for compatibility with the requirements of River-Basin Management Plans.     

Eutrophication of Tamar Lakes (1975–2003): a case study of land-use impacts, potential solutions and fundamental issues for the Water Framework Directive

Tamar Lakes is comprised of two reservoirs, which are located in South West England and in the headwaters of River Tamar at approximately 135 m above ordnance datum. Upper Tamar Lake (UTL) is a direct feed source reservoir of potable water in North Cornwall. Immediately following completion in 1975, UTL was subject to intense blue‐green algal blooms that continue to the present. These blooms create operational problems for water treatment, especially in hot‐dry years. Lower Tamar Lake (LTL) was constructed as a water supply reservoir in 1819 and became obsolete following UTL coming on‐line. Detailed water quality investigations over a period of some 28 years have confirmed the source of nutrient enrichment that fuels the algal blooms to be agriculturally derived, corresponding with a substantial increase in livestock farming. Associated poor land management practices, such as extensive field drainage and inappropriate slurry disposal to land, are linked with substantial elevations in organic contaminants such as ammonia, biochemical oxygen demand (BOD) and suspended solids (SS) during rainfall events. Evidence demonstrates that both reservoirs act as primary treatment lagoons, substantially reducing the worst of these pollutants and providing significant environmental gain. The implications of the Common Agricultural Policy (CAP), the Water Framework Directive (WFD) and regulatory monitoring are discussed in relation to resource management.     

Effects of water sample preservation and storage on nitrogen and phosphorus determinations: implications for the use of automated sampling equipment

The effects of freezing, acidification, refrigeration and extended storage without refrigeration on measured concentrations of forms of nitrogen and phosphorus were assessed in water samples taken from polluted and unpolluted streams in dry and wet weather. Emphasis was placed on likely changes associated with the use of automatic samplers in field conditions. The response of measured nutrient concentrations to different preservation methods and to extended storage without preservation varied widely between samples. For polluted streams where nutrient concentrations were high (ammoniacal nitrogen >0.1 mg l⁻¹; oxidised nitrogen, total Kjeldahl nitrogen, total and filterable phosphorus >1 mg l⁻¹), there was generally little proportional change in nutrients other than ammoniacal nitrogen after up to 6 d of storage without preservation. Where nutrient concentrations were low, up to 90% of ammoniacal nitrogen, 50% of oxidised nitrogen, 84% of total Kjeldahl nitrogen and 67% of total phosphorus was lost after 6 d. If samples cannot be retrieved immediately, automatic samplers should be refrigerated where possible. Acidification is a suitable alternative for preservation of nitrogen. Samples for filterable phosphorus should be filtered as soon as possible after collection. In some circumstances, unpreserved samples may provide an acceptable level of accuracy for evaluation of broad temporal trends or estimation of nutrient loadings.     

基于MIKE21模型的排涝方案模拟研究——以中新生态城旅游区北部水系为例

中新生态城旅游区内现有水域均为独立的小水体,不连通且无外排通路,严重影响区域的防汛排涝能力,因此确定合理的水系排涝规划方案是保障区域防洪安全的重点。通过连通小水域形成整体水系、增设外排泵闸等工程措施,建立健全的防汛排涝体系,同时还能增加区域槽蓄容量。利用DHI MIKE数学模型的研究方法,对北部水系排涝工况进行数值模拟,确定河道及各连通节点规模,拟定区域排涝调度模式,提出水系排涝规划的优化方案,增强防汛除涝能力及水资源调度能力,提升区域整体水环境质量,保证旅游区生态建设,符合绿色生态城的建设理念。     

Uncertainty analysis of parameters in non‐point source pollution simulation: case study of the application of the Soil and Water Assessment Tool model to Yitong River watershed in northeast China

Uncertainty analysis of the model parameters in non‐point source pollution (NPSP) simulation is important because of its great effects on predictions and decision‐making. Understanding the main parameters that effect the uncertainty of NPSP is necessary to provide the basis for formulating control measures. In this study, two methods were applied to conduct parameter uncertainty analysis for Soil and Water Assessment Tool (SWAT). Sobol’ method was used to screen out the model parameters with great effects on the runoff, sediment, total nitrogen (TN) and total phosphorus (TP). The results obtained by sensitivity analysis were used subsequent model calibration and further uncertainty analysis. Monte Carlo (MC) method was employed to analyse the effects of parameter uncertainty on the model outputs. However, such problems are time‐consuming because the MC method required to invoke simulation model thousands of times. To address this challenge, a kriging surrogate model was developed to improve the overall calculation efficiency. The results obtained by sensitivity analysis showed that curve number value (CN2), soil evaporation compensation factor (ESCO), universal soil loss equation support practice factor (USLE_P) and initial organic nitrogen concentration in soil layer (SOL_ORGN) had significant effects on the SWAT outputs. The uncertainty analysis results showed that the uncertainty of runoff is the lowest, followed by TP and TN, and the uncertainty of sediment was the greatest. The kriging surrogate model has the ability to solve this time‐consuming problem rapidly with a high degree of accuracy, and thus it is very robust.     

基于城市更新视角的旧城中心区水系整治——以广州荔枝湾涌、东濠涌为例

以广州市荔枝湾涌、东濠涌整治工程为例,从城市更新的角度探讨大事件促成的旧城中心区水系整治所面临的种种问题及措施.先简要分析当前中国城市更新和旧城中心区水系整治的关系和主要特点,继而介绍广州市2项重点工程的主要内容.在此基础上从更新目标与效果差异、利益格局多元博弈、管理机制内在失谐、更新发展难以持续4个方面分析其中的冲突,并思考整治方法的不足.最后提出旧城中心区水系整治是历史文化生态综合廊道的建设,另外也需注意社会经济和管理制度2个方面的重要作用.     

基于安全、生态、景观三要素的城市水系规划——以阜南新区水系整治规划为例

该文提出从城市安全、生态、景观三大格局出发,统一规划城市水系的防洪排涝功能、生态功能与景观功能。并以阜南新区水系整治规划为例,运用这三大规划策略与措施,构建满足安全、生态、景观三方面功能的城市水系格局,从而达到水城相融的效果,营造一个富于淮北水乡地域特色的阜阳城南新区。