Optimal Sizing of Rainwater Harvesting Tanks for Domestic Use in Greece

Water Resources Management - Rainwater harvesting gains more and more ground as a modern, relatively inexpensive and simple water-saving technology, and as a sustainable water management practice,...     

GIS-based Methodology for Identification of Suitable Locations for Rainwater Harvesting Structures

Presently, the water resources across the world are being continuously depleted. It is essential to find sustainable solutions for this shortage of water. Rainwater harvesting is one such promising solution to this problem. This paper presents a new GIS-based methodology to identify suitable locations for rainwater harvesting structures using only freely available imageries/remote sensing data and data from other sources. The methodology has been developed for the semi-arid environment of Khushkhera-Bhiwadi-Neemrana Investment Region (KBNIR) in Alwar district of Rajasthan. For identifying locations suitable for rainwater harvesting structures, the layers of surface elevation (ASTER-DEM), landuse/landcover, soil map, drainage map and depression map are used and further analyzed for their depression volume, and availability of surface runoff using Soil Conservation Service - Curve Number (SCS-CN) method. Based on the proposed criteria total seven locations were identified, out of which two locations are excellent; three locations are good, (if provisions of overflow structure are made for them) and two locations are not suitable for rain water harvesting. The total rainwater harvesting potential of the study area is 54.49 million cubic meters which is sufficient to meet the water requirements if harvested and conserved properly. This methodology is time-saving and cost-effective. It can minimize cost of earthwork and can be utilized for the planning of cost effective water resource management.     

Integrated Approach for Identifying Suitable Sites for Rainwater Harvesting Structures for Groundwater Augmentation in Basaltic Terrain

Integrated hydrological, geophysical and groundwater modeling studies has been carried out for identification of suitable sites for rainwater harvesting structures for groundwater augmentation in RRCAT Campus, Indore, M.P. Based on these studies ten check dams, two contour bunds and one earthen bund were recommended on the existing stream channels and in valley fills respectively. Likely water impoundment on these structures was calculated keeping in view the length and width of stream channels. Based on these study a groundwater flow model using MODFLOW were carried out keeping in view the geologic and hydrologic conditions of the area. The net rechargeable impounded rain water from these structures to groundwater regime was calculated for monsoon seasons which varied from 20 % to 48 % and net enhancement of groundwater recharge from all structures would be around 0.11 mcm/year and the water level in the existing well would rise by 2–3 m above its present level for future Groundwater augmentation.     

Assessing the Potential for Rainwater Harvesting

Rainwater harvesting is one of the promising ways of supplementing the surface and underground scarce water resources in areas where existing water supply system is inadequate to meet demand. Rainwater harvesting is one of the measure for reducing impact of climate change on water supplies. Abeokuta has a mean annual rainfall of 1,156 mm which makes rainwater harvesting ideal. Intra annual variability lies betwen 0.7 and 1.0 while the inter annual variability was 0.2. Annually 74.0 m³ of rainwater can be harvested per household. Estimated annual water demand for flushing, laundry and flushing were 21.6 and 29.4 m³ respectively. Harvested rainwater in Abeokuta can satisfy household monthly water demand for WC flushing and laundry except for November, December, January and February. The excess rainwater stored in September and October is sufficient to supplement the short fall in the dry months provided there is adequate storage.Water savings potential is highest in June and September which is the two rainfall peak period in Southwest Nigeria.     

层次分析法在行业水权分配中的应用

层次分析法在处理客观实际问题时,把一个复杂系统问题表示为有序的递阶层次结构,通过人们的判断对决策方案的优劣进行排序,把定性因素定量化,然后计算待评价因素相对于决策目标的优先次序,给出不同行业获得水权的优先权的相对权重并对整个递阶层次模型判断的一致性检验。     

Rainwater storage in cement jars in Northeastern Thailand

The supply of drinking water in the rural Northeast of Thailand has long been a problem. Since the early 1980s the government has promoted 2000 l cement rainwater storage jars for drinking water. Examined here are issues related to the government's programme: jar acquisition and ownership; construction quality; use of jar water; rainwater collection systems and access; water quality; taste preferences; and water storage and shortages. It is found that, while having problems, the programme has been successful: village water storage capacity has increased; villagers are drinking better‐quality water for longer periods; and the acceptance of jars has improved.     

Identifying Potential Rainwater Harvesting Sites of a Semi-arid, Basaltic Region of Western India, Using SCS-CN Method

Upper Karha watershed from semi-arid part of Deccan Volcanic Province, India was investigated to identify the potential sites to construct rainwater harvesting structures with the help of remote sensing and geographical information system. Attempt was made to understand the basaltic terrain in spatial context to find out the rainwater harvesting structures like farm ponds, percolation tank, check dams and gully plugs deriving from thematic layers, such as landuse/landcover, slope, soil, drainage and runoff from Landsat Thematic Mapper imagery and other collateral data. Subsequently, these layers were processed to derive runoff from Soil Conservation Service Curve Number (SCS-CN) method using Arc-CN runoff tool. The SCS-CN method shows that the high runoff potential is from water-body, agriculture land (including harvested land) and followed by settlement, open scrub, dense scrub and low for the open forest, dense forest area. Parameters like hydro-geomorphology, geology were considered as per Integrated Mission for Sustainable Development specifications for identification of the structures. The thematic layers overlaid using intersection based on these specifications. Derived sites were investigated for its suitability and implementation by ground truth field verification. In conclusion, the method adopted in present study deciphers the more precise, accurate and ability to process large catchment area than other methods.     

An Optimization Approach for Assessing the Reliability of Rainwater Harvesting

This study was aimed at developing an optimization approach to rainwater harvesting (RWH) considering three (3) water consumption scenarios (WCS). These scenarios which include basic water need (BWN), pour flush (PF) and full plumbing connection (FPC) corresponding to 50 litres per capita per day (lpcd), 75(lpcd) and 150(lpcd) respectively were simulated for different categories of buildings. Reliability of supply was determined by first obtaining composite surplus/deficit of rainwater followed by optimizing the redistribution of surplus rainwater harvested to deficient buildings. Results showed that when total annual rainfall intercepted by roof exceeded total demand, 100% reliability of water supply was guaranteed. Reliability was found to be a linear function of storage. When reliability of supply is possible, the optimized storage bears an inverse exponential relationship to the roof plan area per capita. The relationship between surplus/deficit and roof plan area per capita follows a one-phase decay pattern. An optimal redistribution of surplus water from self-sufficient buildings to deficient ones gave an improvement in supply reliability from 64 to 87% for basic water need, 47 to 58% for pour flush and 28 to 29% for full plumbing connection.     

层次分析法在水电项目环境成本分析中的应用

层次分析法在进行综合评价方面所显示出来的系统性、简洁性、灵活性,使它在各个领域内都有广泛的应用.应用这一方法在水电项目环境成本分析方面作了初步的探索.研究表明,土地资源、水资源、生物资源消耗成本、移民环境成本及矿产资源消耗成本对项目环境成本的影响最大.     

基于EF-AHP法的坝式小水电站生态环境影响评价

坝式小水电在发挥“以电代柴”效益的同时,也对水资源及水生态环境产生了一定的负面影响。开展坝式小水电站生态环境影响评价研究,对于合理开发水资源,协调水电站开发与流域自然、社会、经济之间的关系具有重要意义。根据坝式小水电站的生态环境影响特点,应用层次分析法建立了指标评分体系,结合生态足迹法的思想来赋予各指标权重,构建了基于EF-AHP法的坝式小水电站综合评价模型,选取西北地区某坝式电站进行了案例应用分析,探讨了评价体系的适用性。结果表明,该模型提高了不同电站之间生态环境影响评价结果的可比性、客观性、实用性。该指标体系为客观评价坝式小水电生态环境影响提供了新的科学手段,对掌握小水电生态环境效应具有重要意义。     

Real Options Analysis as an Economic Evaluation Method for Rainwater Harvesting Systems

Water Resources Management - Rainwater harvesting systems (RWHSs) are increasingly employed to reduce the impact of water scarcity in urban buildings. Implementation depends on their financial...     

基于改进的层次法的防渗方案优化分析

黄壁庄水库副坝工程自投入运行以来,坝身及上游铺盖多次发生裂缝及踏坑;下游排水沟及减压井多次发生冒沙和管涌现象。采用一种改进的层次分析法,从可靠性、耐久性、施工条件、运行管理、经济因素及环境因素六个方面对河北省水利厅提出的四种防渗方案进行综合评价。结果表明,坝顶组合垂直防渗方案为最优防渗方案。     

Water Management,Rainwater Harvesting and Predictive Variables in Rural Households

Water management in rural domestic households plays an important role in reducing water-related health risks. This study was conducted to examine the relationships between the dependent variable (rural domestic rainwater management) and the independent predictive variables (personal characteristics, tank size, years of water harvest, rainwater harvesting associations, usage instructions including water borne health risk, and tank operation and maintenance) in Uganda. Logistic regression techniques were used on a random sample of 301 respondents to ascertain the influence of predictive variables on rural domestic rainwater management. Analyses of the hypothesised relationship revealed three statistically significant results: years of water harvest, rainwater harvesting associations and usage instructions. Overall, the findings suggest that consideration of usage instructions including waterborne health risks, years of harvest, and local water associations, will improve domestic water management, in combination with progressive measures focused on water quality and quantity. Moreover, medical expenses and time spent in hospitals or health dispensaries will be minimised and saved through utilisation of usage instructions. Experienced harvesting households, those with few years of harvest, and non participants as well in local water associations will easily enrich knowledge of how to minimise contracting water-related diseases.     

Sustainability of Rainwater Harvesting Systems in Rural Catchment of Sub-Saharan Africa

Sustainability of rainwater harvesting in enhancing water productivity in various biophysical and socioeconomic conditions of SSA is a key in large scale livelihood improvement. A study was undertaken in Makanya catchment of rural Tanzania to assess sustainability of storage type of rainwater harvesting systems including microdam, dug out pond, sub-surface runoff harvesting tank and rooftop rainwater harvesting system. The increasing population in upstream areas of the catchment has forced use of RWH systems for streams and river water abstraction. The agricultural intensification in hillslopes has affected the water availability for downstream uses. Rainfall variability, runoff quality and quantity, local skills and investment capacity, labour availability and institutional support influence sustainability of rainwater harvesting systems.     

Policies and Strategies to Overcome Barriers to Rainwater Harvesting for Urban Use in Ethiopia

The Ethiopian government has been working on rainwater harvesting (RWH) for more than three decades. Despite its efforts, the results are not as expected. Different barriers have posed challenges to promoting RWH in Ethiopia. This study was done to identify the main problems and obstacles, and reflect on potential solutions. As a result, absence of clear policy definitions, lack of sustainably implemented projects, poor societal perceptions of RWH, local professionals lacking proper knowledge, and initial investment costs are found to be major causes of poor outcomes. Considering the site-specific nature of water issues, the authors propose various management strategies such as policy-oriented promotion, formulation of design guidelines, proactive planning, collaborative research, and integration of RWH with cost covering practices.     

壶关县雨水集蓄利用的可行性探讨

壶关县的水资源严重短缺,文中收集了当地三种蔬菜作物的灌溉制度,计算了其作物需水量和可能集蓄的雨水资源量,进行了供需水平衡分析。结果表明,集蓄雨水资源完全能够满足农作物灌溉的需要。壶关县通过集水窖对雨水资源收集储存,并应用于农作物灌溉上,这一举措不仅可以解决水资源短缺问题,而且对现状缺水靠天吃饭的农村均具有示范作用。     

关于衡水湖环境功能区划的研究

对衡水湖进行环境功能分区是解决引江水资源保护和利用的重要举措。本文通过大量的调查和研究，在选取了切合当地实际情况的环境功能区划方案的基础上，通过对衡水湖环境、社会和技术经济进行综合分析，利用层次分析法对备选方案进行遴选，确定了其最佳利用模式，可以为目前我国环境综合利用及管理提供有益的参考。     

Application of HEC-HMS Model for Evaluation of Rainwater Harvesting Potential in a Semi-arid City

Water Resources Management - With many countries facing water scarcity and the demand for water ever-increasing, more people are turning to rainwater harvesting (RWH) as a feasible way of...     

基于遗传-层次分析法的堤防安全综合评价

基于堤防工程安全影响因素多、关系复杂的特点,在对堤防安全综合评价指标体系构建的基础上,应用层次分析法、遗传算法以及集值统计法,构建了堤防安全综合评价模型并探讨了其求解算法。将遗传算法与层次分析法结合起来,研究了判断矩阵一致性检验和堤防安全主要影响因素筛选与权重确定问题;根据专家经验及其对定性指标的评分,运用集值统计法获得其评价值,评价值加权组合所得结果即为堤防的安全评价结果。将该模型应用于某湖泊堤防,得出该堤防的安全评价值为68.69,即该堤防属于轻度危险,从而提出在堤防日常管理中要加强巡查,并在汛前对重点堤段进行维护,发现问题及时解决。     

Temperature Performance of Different Pervious Pavements: Rainwater Harvesting for Energy Recovery Purposes

Pervious pavements offer a solution for rainwater runoff treatment in urban areas, combining storm-water management with water reuse purposes when the sub-bases become rainwater reservoirs. Furthermore, the thermal behaviour research into these systems has demonstrated their contribution to palliating the urban heat island effect in the hottest season and to delaying freezing during the coldest season. Recent investigations related to pervious pavements and their sub-bases have enabled the use of these structures combined with Ground Source Heat Pumps (GSHP) in addition to the other well-known applications. The aim of this field study is to investigate the temperature response observations of the water stored in the sub-bases of different pervious pavements under specific conditions, in order to evaluate the possibility of introducing GSHP technology. The base and sub-base temperatures of different types of pervious pavements were monitored during one year and the results obtained show the differences in pervious pavements temperature compared to air temperature over the period of study; and demonstrate that the sub-base is less affected by the air temperature than the base, due to the insulating capacity of pervious pavements. On the other hand, water samples were taken from the different pervious pavement sub-bases in order to assess the water quality deterioration due to the temperatures reached in the sub-base, focused on investigating the presence of Legionella in this particular aquatic environment.