Assessment of Rainwater Quality in Warri and Environ, Southern Nigeria for Domestic Purposes

The study aimed at assessing the physiochemical characteristics of rainwater in Warri and it environ was investigated. Pb, Zn, Cd, Cu and Cr concentrations in rainwater from roof and non-roof sources were determined using Atomic Absorption Spectrophotometry. Three geospatial locations comprising Jakpa, Udu, and Ubeji were selected based on prevailing anthropogenic activities. The rainwater samples were systematically collected from (aluminum) roof and non-roof sources for the months of April, June, and August and October 2022, treated and analyzed in the laboratory for sixteen physicochemical parameters. Results were statistically analyzed using ANOVA, and T-test for the determination of the level of relationships and variations across geospatial locations. Significant correlations (r = 0.72) exist between Cr in rainwater from roof and non-roof sources. Implying point-source contaminations and may be emanating from the influence of roof materials. Furthermore, high concentrations of Cd and Pb in roof source above WHO standards were mostly in Jakpa and Ubeji. Calculated Health Risk Index (HRI) for children and adult is greater than 1. The results showed that most samples from the locations are considered not safe (HRI > 1) especially for Cd, which means that there are potential health risks consuming rainwater from Jakpa, Udu and Ubeji. Therefore, there is need for prompt sensitization program to dissuade people from directly drinking rainwater from these locations.

Application Strategies of Pipe Jacking Technology in Municipal Rainwater Pipeline Engineering

Traditional construction techniques have a significant impact on the environment and are associated with long construction durations in the construction of municipal rainwater pipelines.Pipe jacking technology,a new type of pipeline construction method,enables non-excavation construction and can address the shortcomings of traditional pipeline construction.This article analyzes the concept and application advantages of pipe jacking technology.Combining engineering examples,it explores the application strategies of pipe jacking technology in the construction process of municipal rainwater pipelines for reference.

Rainwater harvesting systems: An urban flood risk mitigation measure in arid areas

Rainwater harvesting (RWH) systems have been developed to compensate for shortage in the water supply worldwide. Such systems are not very common in arid areas, particularly in the Gulf Region, due to the scarcity of rainfall and their reduced efficiency in covering water demand and reducing water consumption rates. In spite of this, RWH systems have the potential to reduce urban flood risks, particularly in densely populated areas. This study aimed to assess the potential use of RWH systems as urban flood mitigation measures in arid areas. Their utility in the retention of stormwater runoff and the reduction of water depth and extent were evaluated. The study was conducted in a residential area in Bahrain that experienced waterlogging after heavy rainfall events. The water demand patterns of housing units were analyzed, and the daily water balance for RWH tanks was evaluated. The effect of the implementation of RWH systems on the flood volume was evaluated with a two-dimensional hydrodynamic model. Flood simulations were conducted in several rainfall scenarios with different probabilities of occurrence. The results showed significant reductions in the flood depth and flood extent, but these effects were highly dependent on the rainfall intensity of the event. RWH systems are effective flood mitigation measures, particularly in urban arid regions short of proper stormwater control infrastructure, and they enhance the resilience of the built environment to urban floods.

Pollution control of outfall of rainwater-sewage confluence in old town

In order to improve water quality of middle ancient canal in Zhenjiang city a pollution control project was carried out.The research area is the middle catchment area of the ancient canal river system in the old town of Zhenjiang. The specific research object is the runoff of the outfall of rainwater-sewage confluence in the area. On the basis of detecting and analyzing the water yield and water quality of the runoff of rainwater-sewage confluence a combined technology which contains four independent continuous processes for lowering pollution load was developed and system equipment was established and put into operation. The processing effects of the project were monitored and analyzed.The results show that the pollution control project of outfall runoff is efficient which decreases the pollution load including chemical oxygen demand COD total phosphorus TP suspended solids SS and ammonia-nitrogen NH3-N .As a result the water environment of the ancient canal is protected.

Exploration of Sponge System Design in Wetland Parks Based on Rainwater and Flood Control: A Case Study of Southern Anhui Province

Based on the background that wetland resources in China are under threat and urgently need to be protected,a series of rainwater and flood problems caused by urban construction is analyzed comprehensively,and the design and planning methods of wetland parks in response to rainwater and flood disasters caused by floods and heavy rainfall are explored.Southern Anhui with complex and variable terrain and frequent rainfall and flood disasters is selected as the research area,with Xuanzhou District of Xuancheng City as the main research object.The relationship between municipal drainage of urban park and water conservancy drainage is investigated from different sample selection,design samples,and design flow rates.Based on literature review and model building methods,an urban storm flood model suitable for typical wetland parks in southern Anhui is constructed after processing the survey data using Arc GIS,SWMM(storm water management model).On this basis,a methodology and principles for designing a sponge system of wetland park based on rainwater and flood control are proposed,including technical measures such as rainwater collection,retention,and purification.This paper provides certain research results in design schemes,effect evaluations,ecological and social benefits,and useful suggestions and solutions for urban stormwater management and resilience development.

Strategy to Overcome Barriers of Rainwater Harvesting, Case Study Tanzania

There are socio-technological challenges towards extension of the application of rainwater harvesting (RWH) practices in developing countries. An attempt to address this was done using the Mnyundo Primary School, Tanzania, as a study area for evaluating the technical, economic, and social challenges of RWH practices. A storage water level monitoring gauge was used so as to simplify rainwater quantity control and utilization strategy. Basic quality control components such as first flush tank were incorporated so as to reduce the particle load flowing into the storage. Cost reduction strategies such as the one (1) company one (1) community campaign were applied to address the cost implication. To enhance ownership, participatory approach of the beneficiaries in all stages including planning, designing and implementation was adopted. In order to ensure project sustainability, training on how to operate and maintain were provided as well as a maintenance manual to impart a sense of ownership. For the challenges of imparting RWH practices in Tanzania, 19 solutions have been identified and they include provision of RWH manuals, guidelines and regulations, government incentives, and promotion of self-financing initiatives. For developing countries, the study proposes the following strategies: establishing relevant regulations and research centers, enhancing individual and community financial stability, conducting demonstration projects, and increased investment by government on promotion.

Design Method of Rainwater Harvesting System for Afforestation in Loess Plateau

On the basis of natural conditions of lack of rainfall on the Loess Plateau, this paper presents a method of design and construction in rainwater harvesting system for afforestation, which is suitable to the regions of 300 600?mm rainfall. The system consists of micro catchments of various forms and sizes that include planting areas, where trees are planted and trapped runoff, and contributing areas, where overland flow are produced by rainfall. The design is based on rainfall, runoff coefficients of contributing areas, evapotranspiration of trees and soil surface, water deficiency of soil, and environmental capacity of precipitation in the region, and so on. Runoff coefficient of contributing areas with YJG (organic silicon chemical treatment), compacted surface soil slope and natural slope micro catchments, are 0 8 0 89, 0 23 0 36, and 0 08 0 10 respectively. According to the Penman method, the soil water deficiency varies from 50?mm to 300?mm. In the region of 400?mm precipitation, the contributing area treated with YJG is 3 4?m 2 for timber forests, 8 10?m 2 for cash trees respectively; the contributing area treated with compacted soil surface is 6 8?m\+2 for timber forests, 10 12?m 2 for cash trees respectively; the contributing area of natural slope is 8 10?m 2 for timber forests, 12 15?m 2 for cash trees respectively. Transpiration from trees of micro catchment in YJG, compacted surface soil and natural slope treatment is by 47 65% 53 31%, 24 10% 36 93%, and 18 65% 29 55% of total rainfall (rainfall and harvested rainwater) respectively after the system was applied in the region. This system, which has been widely practising on the Loess Plateau, is now known as runoff forestry.

Testing and analysis of rainwater quality in Shenyang

To explore the influence of rainwater quality on rain utilization projects the rainwater of building roofs community runoff and municipal outlets which were taken from Hunnan New District of Shenyang was detected and analyzed for one year. The results show that the main pollutants affecting the quality of the rainwater are chemical oxygen demand COD and suspended solids SS which is especially obvious at the beginning of rainfall. With the duration of the rainfall water quality improves.The contents of COD and SS in municipal outlets are the highest which are 167 to 249 mg/L and 119 to 332 mg/L respectively. The contents of COD and SS are 27 to 85 and 106 to 269 mg/L in community runoff 15 to 80 and 50 to 153 mg/L in the rainwater of building roofs.NH4＋-N concentrations of the three sampling sites are 1.7 to 5.2 3.7 to 18.2 and 5.2 to 25.6 mg/L.

Estimating runoff coefficient for quantity assessment of roof rainwater harvesting system

In order to accurately estimate the runoff coefficient for the quantity assessment of the roof rainwater harvesting system RRHS great differences in the value of event runoff coefficient ψERC were observed by field monitoring under different roof types roof slope and material and diverse rainfall distributions rainfall depth and intensity in three years 2010 to 2012 in Handan Hebei China.The results indicate that the distribution of ψERC is more highly correlated with the event rainfall depth than other factors. The relationship between ψERC and the rainfall depth can be well represented by the piecewise linear function.Further based on the daily rainfall data over the period from 1960 to 2008 the value of the annual runoff coefficient ψARC is calculated. Although the total rainfall depth in each year is different ψARC in Handan can be considered as a constant 0.62 approximately. The results can be used for the quantity assessment and performance analysis of the RRHS.

Practice and analysis of recycling non-drinking water from air-condition and reverse-osmosis system into rainwater collection system

This paper is based on the rainwater collection project in the retrofit of the Dongyi teaching block in Zhejiang University Xixi Campus.The analysis incorporates the local meteorological data, recycling water utilization, and precipitation adjustment.The rainwater collection system in this program also adds the condensation water from the heating, ventilation and air conditioning （ HVAC） system and the concentration from the reverse-osmosis system used for watering greens and supplying waterscapes.By calculating, the quantity of the HVAC condensation water in summer is 3.48 m3/d, and the quantity of the reverse-osmosis concentrated water is 198 to 396 L/d.This method solves the water shortage caused by high evaporation in summer and low precipitation in winter.Supported by empirical monitoring data, the proposed method significantly increases the economic efficiency of the system during the summer period.

Rainwater utilization and storm pollution control based on urban runoff characterization

The characteristics of urban runoffs and their impact on rainwater utilization and storm pollution control were investigated in three different functional areas of Zhengzhou City, China. The results showed that in the same rain event the pollutant loads （chemical oxygen demand （COD） and total suspended solids （TSS）） in the sampling areas were in the order of industrial area 〉 commercial area 〉 residential area, and within the same area the COD and TSS concentrations of road runoffs were higher than those of roof runoffs. The first flush effects in roof and road runoffs were observed, hence the initial rainwater should be treated separately to reduce rainwater utilization cost and control storm pollution. The initial roof rainfall of 2 mm in residential area, 5 mm in commercial area and 10 mm in industrial area, and the initial road rainfall of 4 mm in residential area and all the road rainfall in commercial and industrial areas should be collected and treated accordingly before direct discharge or utilization. Based on the strong correlation between COD and TSS （R2, 0.87-0.95） and the low biodegradation capacity （biochemical oxygen demand BOD5/COD 〈 0.3）, a sedimentation process and an effective filtration system composed of soil and slag were designed to treat the initial rainwater, which could remove over 90% of the pollutant loads. The above results may help to develop better rainwater utilization and pollution control strategies for cities with water shortages.

Design and Construction of Rainwater Harvesting and Water-saving Irrigation System of Toona sinensis on Mountain Slopes

In order to collect rainwater and resist drought to enhance the utilization rate of rainfall and water resources, through project rainwater harvesting measures, the total annual rainwater harvesting amount of the six greenhouses was calculated according to annual average precipitation 542.2 mm, up to 1 095.7 m^3. The upper natural slopes of cultivated land were as rainwater harvesting areas, and total annual rainwater harvesting amount was 49 242 m^3 on the mountain slopes with an area of 73.37 hm^2, while total water storage amount was 39 394 m^3 in theory, so it could meet water use for the irrigation of 26.28 hm^2 of T. sinensis land. To be convenient for rainwater harvesting, irrigation and supplying water to the water-saving cellars, one pert-cut and part-fill reservoir （which was 470 m^3 in volume） was built on the mountain slopes at the right rear of the greenhouses, and their altitude difference was 50 m. The reservoir was sealed and was built with reinforced concrete. Water-saving cellars were distributed in front and the middle and at the back of two rows of greenhouses, and they were connected with each other. The reservoir could supply water to the water-saving cellars and also collect water by mountain slopes, from the lower water-saving cellars or deep wells. Two rainwater hervesting ditches that were 1 650 m in length were at the lower edge of arable land in the upper reaches of slopes to intercept rainfall runoff and make it flow into channels and then the sedimentation tanks. The total annual rainwater harvesting amount of the reservoir and water-saving cellars was 1 222.5 m^3.

Rooftop Rainwater Harvesting as an Alternative Domestic Water Resource in Zambia

Within the last decade, substantial progress has been achieved in the management of centralized water reticulation in Zambia. Characterized by diversified fiscal resourcing, concurrent institutional restructuring and introduction of new players in water governance, the water sector is set to achieve improved reliability on sustainable grounds. However, the threat of underground water pollution resulting from increased urbanization besides the unreliable energy sector presents new challenges for the current urban water. In effect, urban areas are affected by chronic water rationing creating public stress and insecurity which impacts domestic development. While the course of development has meant investment in the extension and expansion of water infrastructure in Zambia, alternative urban water resources are being sought to address challenges of traditional water systems globally. This paper therefore attempts to make a case for the modernization of Rooftop Rainwater Harvesting (RRWH) as an augmenting water resource in the Zambian urban housing sector. Here—in, it is identified as a Low Impact Development technology within the Integrated Urban Water Management framework currently being forged by local water. Based on a desktop literature survey and online questionnaire survey, an argument to support the development of RRWH in Zambia was developed. While literature survey results revealed evidence of economic loss and a growing compromise to public health resulting from inconsistent water supply in the study area of Lusaka city, the online questionnaire survey depicted significant domestic stress due to erratic water supply. Results confirmed that at one time residents observed an average of eight hours of power blackouts which effectively induced water disruption forcing homeowners to engage in various water storage methods which in turn are costly on domestic time, health and finances. A retrospective discussion based on both survey results attempts to present benefits and opportunities of urban RRWH to water sector stakeholders providing recommendations towards the mainstreaming of the practice in Zambia.

Potential of rooftop rainwater harvesting to meet outdoor water demand in arid regions

The feasibility of rooftop rainwater harvesting （RRWH） as an alternative source of water to meet the outdoor water demand in nine states of the U.S. was evaluated using a system dynamics model developed in Systems Thinking, Experimental Learning Laboratory with Animation. The state of Arizona was selected to evaluate the effects of the selected model parameters on the efficacy of RRWH since among the nine states the arid region of Arizona showed the least potential of meeting the outdoor water demand with rain harvested water. The analyses were conducted on a monthly basis across a 10-year projected period from 2015 to 2024. The results showed that RRWH as a potential source of water was highly sensitive to certain model parameters such as the outdoor water demand, the use of desert landscaping, and the percentage of existing houses with RRWH. A significant difference （as high as 37.5%） in rainwater potential was observed between the projected wet and dry climate conditions in Arizona. The analysis of the dynamics of the storage tanks suggested that a 1.0-2.0 m3 rainwater barrel, on an average, can store approximately 80% of the monthly rainwater generated from the rooftops in Arizona, even across the high seasonal variation. This interactive model can be used as a quick estimator of the amount of water that could be generated, stored, and utilized through RRWH systems in the U.S. under different climate conditions. The findings of such comprehensive analyses may help regional policymakers, especially in arid regions, to develop a sustainable water management infrastructure.

Introduction to rainwater management in Australia and suggestions for China's water problems

Australia is one of the world leaders in water management. The country meets the challenge of water shortage with established integrated water management in which rainwater is taken as a too precious resource to be just drained off. In Australia, rainwater is extensively harvested and polished to provide cheaper supply for potable and non-potable domestic uses, irrigation, landscaping, refilling aquifers and other uses. Implementing dual management over the quantity and quality of storm water and practicing water sensitive urban design (WSUD) in urban areas effectively control non-point-source pollution of waterways by pollutants carried with runoffs, reduce the discharge of rainwater and thus protect properties and lives from damage by floods. These achievements are attributed to constant reinforcement by govenments from federal to local levels in policy, financial, legal and educational aspects, and also to the lasting efforts of professional communities and water industry in developing requisite techniques, demonstrating the benefits and fostering public credence of rainwater reuse. The successful rainwater management practices in Australia suggest rainwater harvesting can be a complimentary means for the South-to-North Water Transfer Scheme to solve the water shortage in China's northern regions, and thus release to a degree the pressure on the Yangtze water resources. Best management practices of rainwater can be an effective controlling strategy for flooding and non-point-source water pollution of waterways. Such in-site source control initiatives have particular significance to protecting slow waterways of weak self-purification ability, like the Three Gorges Reservior.

Rainwater Harvesting in Multifamily Social Interest Housing

This study evaluated the reduction of water consumption in a SIH （social interest housing） complex from the simulation of implanting a rainwater harvesting system. The methodology consisted of characterization of the case study, survey data of water consumption and data of precipitation in the area, on-site visits to define the average consumption and monthly water distribution, and sizing of a rainwater harvesting tank following the Netuno Program. It was obtained 22.500 L as the ideal volume for the tank, supplying the demand for drinkingwater in 32%, although the reduction in the drinking water bills would be minor, since the object of the case study is considered SIH, and residents pay a fixed fee for consuming up to 10 m3 per month. Therefore, it becomes necessary to analyze this situation from a sustainable and environmental perspective, and the benefits are no longer only economic, but rather they take on a more comprehensive social dimension.

Strategies for Household Water Supply Improvement with Rainwater Harvesting

There are significant household water supply challenges including quantity sufficiency and quality, which have economic and social implications. The challenges have remained despite the efforts of government establishing centralized or groundwater systems, and/or having individual crude systems. A Tanzanian rural household case study was considered by assessing the performance of a currently relied surface runoff collecting pond system for domestic purposes. A daily water balance model was applied with performance parameters, no water days (NWD) and rainwater usage (RUR). Rooftop runoff harvesting system was proposed as a water supply source in addition to the current one. Under such dual supply conditions, users can meet the drinking and non-drinking demand even in dry seasons at a minimum of 2 and 20 L/person/d, respectively. For rainwater harvesting adoption (considering selected regions), it was further established that amount and variation in rainfall impacts on quantity available for meeting demand. Increased catchment implies increased harvestable quantity, and with same storage higher reduction of number of NWD although with slight decrease of RUR. Also, increased storage is required for achieving higher RUR in case the same demand is maintained. But same storage can be maintained for increased demand relative to catchment size. However, rainwater catchment increase has greater impact on meeting a specified demand under given condition of rainfall quantity and variation. The RWH technology strategies presented in this study are replicable in other developing countries under site specific conditions.

Numerical simulatim of rainwater accumulation and flow characteristics over windshield of high-speed trains

In this paper, a Euler-Lagrangian particle/fluid film/VOF coupled multiphase flow model is presented. Numerical simulations are conducted, and the rainwater accumulation and flow characteristics over two types of windshields are studied based on the presented model. The results show that an uneven water film is formed over the windshield, with rain water accumulation occurring for the concave windshield but not for the convex windshield. At low speeds, the average fluid-film thickness for a concave windshield is larger than that of a convex windshield;however, a minor difference occurs between these two values at high speeds, and a critical velocity is observed for the two types of windshields. When the train velocity is less than the critical velocity, the fluid film at the lower part of the windshield and the train nose flows downward, and beyond the critical velocity, the fluid film over the entire windshield and train nose flows upward.

Function of Soils in Regulating Rainwater in Southern China: Impacts of Land Uses and Soils

One of the most important functions of soils is to regulate rainwater and mitigate flooding and associated damages; this function can be estimated by the rainwater regulation ratio （η）, i.e., percent of regulated rainwater. Fifteen experimental plots were set up on the hills in Yingtan of Jiangxi Province, southern China. These plots were under three land use patterns, cultivated cropland, noncultivated land, and orchard interplanted with cash crops. With aid of an artificial rainfall simulator and Guelph method, rainfall, runoff, soil infiltration, and so on were measured in situ. Results showed that the orchard interplanted with cash crops was more effective in regulating rainwater than the other two land use patterns. When the maximum infiltration intensity was three times higher than the observed mean,η was higher than 70% for all plots. 77 was related to land use, slope gradient, and soil properties such as soil infiltration, organic carbon, bulk density, and texture. There is still more room to improve capacity of rainwater drainage （underground percolation） than that of rainwater storage in soils. Therefore, enhancing soil permeability is vital to improve the rainwater regulation efficiency in soils.

A preliminary sustainability assessment of innovative rainwater harvesting for residential properties in the UK

Rainwater harvesting RWH has yet to see significant uptake in UK households primarily due to a lack of innovation in residential RWH system types.This ppa er presents the results of per liminary investigations into a range of traditional and innovative residential-scale RWH systems. These systems are examined using a patent application search informal interviews with industry professionals cost-benefit analysis and a simple multi criteria analysis MCA .The latter examines the sustainability of the systems based on a priori social economic and ne vironmenat l criteria.Two of the innovative systems are subject to a more detailed analysis and benchmarked agains ta rt aditional system.Results of the MCA indicate that the innovative RWH systems achieve better sustainability scores than the traditional RWH with a lower capital cost.Further research is focused on monitoring the identified systems to generate empir cal datasets in order to undertake the WLC/LCAs and to identify challenges associated with installation.