The Influence of Green Roofs on Runoff Water Quality: A Case Study from Estonia

This paper describes the runoff water quality of Light Weight Aggregates (LWA)-based extensive green roofs and sod roofs in Estonia. Samples were taken from August 2004 to April 2009 from 10 different green roofs to determine what level of water quality may be found. The results presented here show that green roofs influenced water quality to a considerable degree. The runoff water of LWA-based green roofs generally had higher values of pH, BOD₇, TP and PO₄-P than that from sod roofs. However, COD, TN, SO₄ and Ca-Mg salt were higher in the sod roofs than in the green roofs. The results for NH₄-N and NO₃-N were similar for both roof types. According to the results, the character of the runoff and the contents in the substrate layer at the moment the samples were taken affected runoff quality more than the age and location of the green roof. The use of NPK-nutrients in the substrate or in the soil caused much higher values of COD and concentrations of TP, PO₄-P, TN, NH₄-N and NO₃-N in runoff water than on non-fertilized green roofs. The results of samples taken from the Tartu LWA-based green roof each spring in the period 2005–2009, at a time when the snow had almost melted, showed that concentrations of compounds in runoff water generally decreased gradually. The pH value and Ca-Mg salt concentration were, however, stable, and this was caused by the LWA material.     

Performance of Green Roofs for Rainwater Control

Water Resources Management - Green roofs can be an effective tool for sustainable urban drainage, since they reduce and retain runoff by delaying its peak. Most studies analysing the retention...     

Irrigation Water Quality Requirements

ABSTRACT

Rational use of salinized water contributes to the saving of water resources, enlargement of irrigated areas and increased volumes of agricultural produce. It is ascertained that there are several distinguishable levels in irrigation water quality requirements, depending on climatic conditions, drainage conditions OF the territory, fertility, texture and properties of soil, and salt resistance of agricultural crops. In cases where irrigation water quality requirements are not adhered to soil fertility deteriorates, thereby reducing the yield and quality of agricultural produce.

Restrictions on irrigation water quality increase with transfer From the desert zone to dry steppe and steppe.

Thus, the source of irrigation water should be assessed from the viewpoint of alkalinization and salinization hazards with respect to crops of different salt resistance in the steppe, dry steppe and desert zones.     

作物需水量与灌溉制度模拟

从作物需水量的基本概念出发，以水量平衡原理为基础，建立了模拟农田根层土壤水循环的计算机模型-ISAREG.这一模型具有多种功能，可模拟根层土壤水分变化，评价给定的灌溉制度，计算作物需水量和灌溉需水量，也可用以制订多种供水限制条件下的优化灌溉制度．用望都灌溉试验站的小麦、玉米、棉花3种作物两年的试验观测资料对上述模型进行了验证．     

兴凯湖灌区工程后产流分析

兴凯湖灌区位于黑龙江省三江平原,区内缺少水文站,以往工作中灌区内地表径流均以水文图集中年径流深成果采用等值线图法进行估算,考虑区域内径流等值线稀疏,估算径流成果误差较大,采用平原水网地区常用的地面分类法简化计算模型对灌区工程后产流状况进行分析,该方法简单,概念明确,计算成果合理,方便于计算机操作,分析成果可以作为工程规划阶段的计算依据。     

潇湘水库径流模拟及其灌溉配水研究

结合云南省曲靖市潇湘水库灌区工程实际，首先采用随机动态规划模型模拟潇湘水库的年径流、月径流，得到水库的入库径流过程，再根据系统论的思想建立了节水灌溉水量最优分配的模型：大系统分解——协调模型，获得了灌溉水量的最优分配方案。     

西北地区节水灌溉市场与技术需求

西部开发需要大量的生态用水，从节水灌溉设备市场分析，节水灌溉专用泵阀、新型输水管材、高效低能喷微灌设备及材料的需求量很大，技术需求与亟待研究开发的关键技术和设备也很多。从西北地区水资源状况与需求看，节水灌溉市场有很大潜力。     

The Role of Green Roofs as a Source/sink of Pollutants in Storm Water Outflows

Green roofs are increasingly used as sustainable urban drainage systems due to their retention and detention capacity; however, the impact of green roofs in term of water quality is still a debated issue among researchers. A monitoring programme was carried out at the University of Genoa on a full-scale experimental site to assess the quality of storm water outflows. As for rainfall, the bulk deposition (dry and wet fractions) is collected to evaluate the role of the overall atmospheric deposition in altering storm water quality. The pollutant load observed in the green roof outflow is limited; concentration values for solids and metals are lower than those generally observed in storm water runoff from impervious surfaces. Suspended solids and Chemical Oxygen Demand (COD) are below respectively 10 and 20 mg/l, on average; as for heavy metals, copper and zinc are equal to 30 μg/l on average, while iron is equal to 120 μg/l. The Event Mean Concentration (EMC) statistics of the pollutant loads associated with the rainfall and outflow have been compared and discussed. The observed green roof behaviour as a sink/source of pollutants with respect to the atmospheric deposition is also investigated based on both concentration and mass. Results demonstrate that: green roof behaves as a source with respect to solids, COD and potassium while zinc and mainly copper are retained within the green roof stratigraphy. The resulting mass delivery behaviour reveals that no significant first flush occurs for pollutant constituents irrespective of the hydrologic characteristics and pollutant sources.     

泾惠渠灌区降水径流奇异谱分析

泾惠渠灌区是陕西省主要产粮区之一,灌区降水径流等水资源对于灌区的农业生产关系重大,分析灌区降水径流特性,明确灌区降水径流的主要影响因素,是灌区合理规划利用各种水资源的基础。降水径流等水文要素成因复杂,受气候因素影响具有周期性震荡特性,采用能够降噪和降维的奇异谱分析(SSA)方法对泾惠渠灌区降水径流时间序列震荡特征进行分析。分析显示,灌区降水径流时间序列均具有准3~4 a,9~12 a,18~22 a的周期性,与东部季风、太阳黑子等现象的周期性活动关系密切。由此表明,泾惠渠降水径流主要受东部季风的影响,且受太阳黑子等大尺度周期性因素的综合影响。     

暴雨条件下沙棘林减水减沙效益研究

造成黄土高原水土流失的降雨主要是短历时暴雨。根据这一特点，利用人工模拟降雨方法研究了短历时暴雨条件下沙棘林的减水减沙效益，以及不同郁闭度对产流产沙过程的影响。结果表明，沙棘林郁闭度越高，减水减沙效益越好。     

宝鸡峡灌区灌溉引水对渭河径流量的影响

宝鸡峡灌区农业灌溉引用渭河水已对渭河生态造成了显著影响。渭河年径流量存在年际差异大的特点,而宝鸡峡渠首引水则多年维持在5.30亿m3/a左右,从而造成枯水年渭河生态基流的缺失及生态系统的破坏。宝鸡峡灌区引水对渭河径流量的影响主要集中在枯水年的枯水段(11月至翌年4月),引水后生态基流缺失量达1.42亿m3/a。通过改进宝鸡峡灌区灌溉方式和减少灌溉损失可以节水1.27亿m3/a,该水量能缓解宝鸡峡灌区引水对渭河径流量的影响。     

基于改进的BP神经网络径流量还原计算研究

针对水文系统复杂性与非线性的特点,加入动量项因子对BP神经网络进行改进,加快收敛速度,将自然因素、人为因素、自然与人为混合因素分别作为输入因子,构建了大沽夹河天然径流量还原计算方案,用逐项还原法的结果验证对比选出最佳方案。结果表明:①经过改进的BP神经网络收敛速度明显加快,由平均的6 028次迭代优化到1 782次迭代;②以降雨量、蒸发量和实测径流量为输入因子的第三种方案模拟误差最小,适用于大沽夹河流域天然径流量还原计算。     

宁蒙灌区引水对黄河干流径流的影响

采用河段上下断面月径流量关系法、引水分级关系法、多元回归分析法和上下断面径流量差值法,通过对比引水前后下断面径流量与主要影响因素的关系,定量分析了1997—2006年宁蒙引黄灌区引水、净引水对黄河干流径流的影响。结果表明:1997—2006年宁夏灌区每引水1亿m3,石嘴山断面径流量相应减少0.58亿m3,每净引水1亿m3则相应减少0.977亿m3;宁蒙河套灌区每引水1亿m3,三湖河口断面径流量将相应减少0.653亿m3,每净引水1亿m3则相应减少0.981亿m3;宁蒙灌区每引水1亿m3,头道拐断面径流量将相应减少约0.662亿m3,每净引水1亿m3则相应减少约0.983亿m3。宁蒙引黄灌区引水对黄河干流径流量的影响程度主要决定于灌区净引水量,灌区引水造成黄河干流径流的减少量与灌区的退引比有关。     

塔里木盆地灌溉与环保(二期)工程塔河干流子项目对塔河下游绿色走廊的影响

为了挽救塔里木河下游绿色走廊 ,世界银行塔 (二 )项目中安排了塔河干流子项目。本文针对干流子项目工程布置的特点 ,分析研究了项目实施后对塔河下游输水的影响 ,最后得出 ,项目完成后 ,每年可从大西海子水库增加下泄 1 2亿m3 的水量 ,对下游绿色走廊生态环境将起到显著的改善作用 ,意义深远     

Effectiveness of Rainwater Harvesting in Runoff Volume Reduction in a Planned Industrial Park,China

It is urgent to effectively mitigate flood disasters in humid mountainous areas in southeastern China for the increasing flood risk under urbanization and industrialization. In this study, a rural district with an area of 13.39 km² that planning to build an industrial park covering an area of 7.98 km² in Changting was selected to estimate the potential of collectable rainwater and the extent to which runoff volume can potentially be mitigated by rainwater harvesting. In addition, the optimum cistern capacity of a rainwater harvesting system in the planned industrial park was evaluated using daily water balance simulation and cost-efficiency analysis. The results showed that rainwater harvesting in the planned industrial park has great potential. The annually collectable rainwater is approximately 9.8?×?10⁶ m³ and the optimum cistern capacity is determined to be 0.9?×?10⁶ m³. With the optimum cistern capacity, the annual rainwater usage rate is 0.99, showing neither financial savings nor deficits. Rainwater harvesting can reduce 100 % of runoff volume in the cases of critical rainfall storm (50 mm) and annual average maximum daily rainfall (111.2 mm), and 58 % of runoff volume in the case of maximum daily rainfall (233.6 mm), respectively. All surface runoff can be collected and stored in the cisterns when rainfall amount is less than 135.5 mm in a rainstorm event.     

位山引黄灌区规范堤防绿化管护的探索

建设生态型灌区是重视和保护环境的举措.位山灌区立足堤防绿化,坚持生态效益和经济社会效益统筹兼顾,走出一条建设生态型灌区、促进可持续发展的道路.     

皇甫川流域水土保持措施减水减沙分析

皇甫川系黄河的一条多泥沙河流，到1997年年底流域治理度达到了28．2％。随着流域治理度的提高，水土保持措施减水减沙作用逐渐增大。坝地减沙作用大于减水，林地、草地、梯田的减沙作用小于减水。20世纪80年代前林地的减水减沙作用最大，坝地次之；80年代后坝地减水减沙作用最大，林地次之。     

哈尔滨市西部地区抗旱减灾及节水灌溉设想

哈尔滨市所辖七区十二个县 (市 )总面积531 0 0ｋｍ2 ,东部与西部地区在气象条件上有很大差异。受地区东部张广才岭的阻隔 ,东南季风带来的暖湿气团 ,在张广才岭东西两侧形成了我省最大降雨中心。地区东部年平均降雨量高达 80 0ｍｍ ,而西部地区 (双城、呼兰、宾县、巴彦 )年平均降雨量仅为 50 0多ｍｍ(其中双城市为 481 8ｍｍ) ,干旱年份只有 30 0多ｍｍ。地区处于松嫩高平原 ,风大 ,蒸发量大 ,是全年降水量的三倍多。而春季蒸发量是降雨量的 5～ 6倍。[1 ]据统计资料表明 ,哈市西部地区春旱发生频率为 70 %～ 75% ,夏旱发生频率为 40 %。…     

波涌灌溉设备与灌溉自动化

结合国家“九五”科技攻关项目开发研制的波涌灌溉设备,达到国际同类产品先进水平,填补了国内空白,双阀结构和控制器的“时间耦合”设计,为我国农田输配水系统实现灌溉自动化提供了支撑。     

古宜河勒黄站受水利工程影响径流还原初探

古宜河勒黄水文站受水利工程影响,观测的年内月径流分配与还原后的年内月径流分配存在差异,已失去天然代表性作用。通过资料还原计算探索径流还原途径,把受水利工程影响的径流量换算为天然径流量,为水利水电建设提供可靠的设计依据。