The effect of selection of time steps and average assumptions on the continuous simulation of rainwater harvesting strategies

2007 ◽  
Vol 55 (4) ◽  
pp. 125-133 ◽  
Author(s):  
P.J. Coombes ◽  
M.E. Barry
Keyword(s):  
Water Demand ◽  
Urban Areas ◽  
Rainwater Harvesting ◽  
Seasonal Distribution ◽  
Continuous Simulation ◽  
Water Demands ◽  
Average Water ◽  
Rainwater Tanks ◽  
Selection Of ◽  
Daily Time

The use of domestic rainwater tanks with back up from mains water supplies in urban areas can produce considerable reductions in mains water demands and stormwater runoff. It is commonplace to analyse the performance of rainwater tanks using continuous simulation with daily time steps and average water use assumptions. This paper compares this simplistic analysis to more detailed analysis that employs 6 minute time steps and climate dependent water demand. The use of daily time steps produced considerable under-estimation of annual rainwater yields that were dependent on tank size, rain depth, seasonal distribution of rainfall, water demand and tank configuration. It is shown that analysis of the performance of rainwater tanks is critically dependent on detailed inputs.

Effects of rainwater harvesting on centralized urban water supply systems

2010 ◽  
Vol 10 (4) ◽  
pp. 570-576 ◽  
Author(s):  
C. Grandet ◽  
P. J. Binning ◽  
P. S. Mikkelsen ◽  
F. Blanchet
Keyword(s):  
Water Demand ◽  
Distribution System ◽  
Urban Areas ◽  
Rainwater Harvesting ◽  
Water Supply Systems ◽  
Urban Water ◽  
Water Infrastructure ◽  
Water Age ◽  
Roof Area ◽  
Supply Systems

The potential effect of widespread rainwater harvesting practices on mains water demand and quality management are investigated for three different types of urban areas characterized by different roof area to water demand ratios. Two rainfall patterns are considered with similar average annual depths but very different temporal distributions. Supply reliability and the extent of reliance on the public distribution system are identified as suitable performance indicators for mains water infrastructure. A uniform temporal distribution of rainfall in an oceanic climate like that of Dinard, Northern France, yielded supply reliabilities close to 100% for reasonable tank sizes (0.065 m3/m2 of roof area in Dinard compared with 0.262 m3/m2 in Nice with a RWSO of 30% for a detached house). However, the collection and use of rainfall results in a permanent decrease in mains water demand leading to an increase in water age in the distribution network. Investigations carried on a real network showed that water age is greatly affected when rainwater supplies more than 30% of the overall water demand. In urban water utilities planning, rainwater supply systems may however be profitable for the community if they enable the deferment of requirements for new mains water infrastructure.

scholarly journals Urban Water Demand Simulation in Residential and Non-Residential Buildings Based on a CityGML Data Model

2020 ◽  
Vol 9 (11) ◽  
pp. 642 ◽  
Author(s):  
Keyu Bao ◽  
Rushikesh Padsala ◽  
Daniela Thrän ◽  
Bastian Schröter
Keyword(s):  
Water Demand ◽  
Urban Areas ◽  
Data Privacy ◽  
Residential Buildings ◽  
Urban Water ◽  
Urban Water Demand ◽  
Water Demands ◽  
Per Capita ◽  
Industrial Water Demand ◽  
Local Water

Humans’ activities in urban areas put a strain on local water resources. This paper introduces a method to accurately simulate the stress urban water demand in Germany puts on local resources on a single-building level, and scalable to regional levels without loss of detail. The method integrates building geometry, building physics, census, socio-economy and meteorological information to provide a general approach to assessing water demands that also overcome obstacles on data aggregation and processing imposed by data privacy guidelines. Three German counties were used as validation cases to prove the feasibility of the presented approach: on average, per capita water demand and aggregated water demand deviates by less than 7% from real demand data. Scenarios applied to a case region Ludwigsburg in Germany, which takes the increment of water price, aging of the population and the climate change into account, show that the residential water demand has the change of −2%, +7% and −0.4% respectively. The industrial water demand increases by 46% due to the development of economy indicated by GDP per capita. The rise of precipitation and temperature raise the water demand in non-residential buildings (excluding industry) of 1%.

scholarly journals Urban Stormwater Management, a Tool for Adapting to Climate Change: From Risk to Resource

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2616
Author(s):  
María Hernández-Hernández ◽  
Jorge Olcina ◽  
Álvaro-Francisco Morote
Keyword(s):  
Climate Change ◽  
Green Infrastructure ◽  
Water Demand ◽  
Urban Areas ◽  
Rainwater Harvesting ◽  
Flood Hazard ◽  
Demand Management ◽  
Urban Water Management ◽  
The Mediterranean ◽  
The City

The effects of climate change on rainfall in the Mediterranean region are manifested in an overall decreasing trend, and greater irregularity in annual volumes and the city of Alicante is no exception. In addition, there has also been a spread of the urbanised area, which has led to an increase in the flood risk in urban areas (due to a greater runoff and the occupation of flood hazard areas) and drought events due to an increase in the water demand. In light of these new scenarios, the Mediterranean cities should design adaptation systems based on rainwater harvesting within the framework of a circular economy. This study analyses the integration of rainwater in flood and water demand management in the city of Alicante (Southern Spain). In recent years, this city has developed infrastructures in order to use these resources. To do this, different databases have been analysed (rainfall and volume of water collected in the green infrastructure systems). The results reveal that stormwater has become highly important in urban water management in Alicante as the city is now using a resource that previously went to waste and created problems (flooding and pollution). By way of conclusion, it is worth mentioning that the incorporation of rainwater for urban use in Alicante has reduced the pressure on traditional resources in satisfying water demand and has also acted as a measure for adapting to climate change.

scholarly journals Rainwater Availability Assessment for Tourism Development: A Case Study of Turtle Islands Park, Sabah

2015 ◽  
Vol 802 ◽  
pp. 575-580
Author(s):  
Janice Lynn Ayog ◽  
Mohd Radzif Taharin ◽  
Tang Zi Sheng
Keyword(s):  
Water Demand ◽  
Tourism Development ◽  
Water Source ◽  
Turtle Species ◽  
Marine Park ◽  
Average Water ◽  
Water Tanks ◽  
Availability Assessment ◽  
Rainwater Tanks

This study mainly focused on the rainwater availability assessment in Turtle Islands Park, Sabah, Malaysia. Consisting of three small islands, this marine park is home to two endangered turtle species – Green and Hawkbills turtles. This special feature of the islands attracts tourist around the world, thus increasing the demand of freshwater supply for tourism development in the marine park. However, due to the shortage of freshwater from the ground due to salinity intrusion, rainwater is seen to be an alternative in fulfilling the freshwater demand. To evaluate the source of freshwater in these islands, information is obtained from the main users of the water source, which are the Sabah Park officers, the approved tour operator on the islands and the security forces. The rainwater tanks available on the islands are calculated to assess the storing capacity of rainwater. The water demand was estimated by multiplying the number of visitors with the average water usage per visitor. With the existing water tanks, this study found that the Turtle Islands Park has the ability to store 414 m3 of rainwater in Selingaan island, 3.2 m3 in Gulisaan island, and 102.1 m3 in Bakkungan Kechil island. However, the monthly water demand of each island exceeds the existing storage tanks, hence it is proposed that the number of rainwater tanks be increased to harvest as much rainfall as possible for the use of the islands’ inhabitants.

scholarly journals Rainwater harvesting as source control option to reduce roof runoff peaks to downstream drainage systems

2015 ◽  
Vol 18 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Alberto Campisano ◽  
Carlo Modica
Keyword(s):  
Water Demand ◽  
Urban Areas ◽  
Rainwater Harvesting ◽  
Control Method ◽  
Source Control ◽  
Peak Reduction ◽  
Free Standing ◽  
Roof Runoff ◽  
Rainwater Tank ◽  
Harvesting Systems

The objective of the paper is to evaluate the potential of tank-based rainwater harvesting systems in free standing houses as the source control method to mitigate peak roof runoff due to rainfall in urban areas. To this aim, the water balance simulation of the rainwater tank was carried out using both high resolution rainfall series and toilet water demand data extracted from the database of results built in a previous field campaign involving six experimental households in southern Italy. Simulations show that significant potential for runoff peak reduction exists, basically depending on the rainwater tank size and on the characteristics of the water demand in the house.

scholarly journals Effect of roof size on the rainwater harvesting tank sizes and performances using Tangki NAHRIM 2.0

2021 ◽  
Vol 920 (1) ◽  
pp. 012035
Author(s):  
N M Daud ◽  
N N Mahiran ◽  
A K Ruslan ◽  
N Hamzah ◽  
A A A Bakar ◽  
...  
Keyword(s):  
Water Demand ◽  
Web Application ◽  
Potable Water ◽  
Rainwater Harvesting ◽  
Balance Model ◽  
Storage Efficiency ◽  
Rainwater Tank ◽  
The World ◽  
Daily Water ◽  
Rainwater Tanks

Abstract Global warming and increasing population have direct impacts on water demand all over the world. Usage of potable water in Malaysia is high if compared with other countries and the source of potable water is mainly surface water. Rainwater harvesting is one of the popular alternatives to water resources around the world. However, even Malaysia is a country with an abundance of rainfall, rainwater harvesting is still unpopular. Different size of houses has different roof sizes which will subsequently require different sizes of rainwater tanks. This study utilized Tangki NAHRIM 2.0 (TN2); a web application to determine the optimal tank size for a rainwater harvesting system for five different roof sizes for non-potable demand. TN2 simulation uses a daily water balance model with rainfall input from a built-in database by adopting the yield-after-spillage (YAS) convention. The optimum rainwater tank sizes for five different roof sizes are found to be between 2.6 m3 and 3.8 m3 with water-saving efficiency values between 59% to 76.2% and 30.9% to 53.9% for storage efficiency. A bigger tank size offers higher watersaving efficiency but with lower storage efficiency. The output will be useful for the application of RWHS to residential houses.

scholarly journals A Long-Term Analysis of the Possibility of Water Recovery for Hydroponic Lettuce Irrigation in an Indoor Vertical Farm. Part 2: Rainwater Harvesting

2020 ◽  
Vol 11 (1) ◽  
pp. 310
Author(s):  
Anna Jurga ◽  
Anna Pacak ◽  
Demis Pandelidis ◽  
Bartosz Kaźmierczak
Keyword(s):  
Water Demand ◽  
Rainwater Harvesting ◽  
Cross Flow ◽  
Vapor Condensation ◽  
Water Recovery ◽  
Air Conditioning System ◽  
Vertical Farming ◽  
Water Vapor Condensation ◽  
Average Water ◽  
Flow Heat

The aim of this study was to determine the suitability of a rainwater harvesting system to cover the water demand for indoor hydroponic lettuce cultivation located in Wrocław (Poland). The analysis was performed on the basis of the recorded rainfall in Wrocław in 2000–2019. The analyzed cultivation is located in a hall with an area of 300 m2, where the lettuce is grown vertically by the hydroponic method. The calculations of the rainwater harvesting (RWH) system were carried out considering the selection of the tank capacity for the collected water. The operation of the water storage is simulated using a yield after spillage (YAS) algorithm. It was evident that the proposed system might be an auxiliary system that relieves the water supply network or supports other water recovery systems (e.g., the water vapor condensation in a cross-flow heat exchanger operating as an element of the air conditioning system, proposed in Part 1 of this study). The harvesting system for the selected vertical farming indoor hall covers an average of 35.9% of water needs and allows a saving of 146,510 L of water annually for the cultivation. An average water demand coverage increases up to 90.4%, which allows a saving of 340,300 L per year when the RWH system is combined with water recovery from exhaust air from the hall.

Spatial Autocorrelation in the Study of Neighbourhoods towards Smart Cities: Empirical Evidence from Kerman, Iran

2012 ◽  
Vol 9 (2) ◽  
pp. 1
Author(s):  
Asra Hosseini
Keyword(s):  
Spatial Autocorrelation ◽  
Urban Areas ◽  
Smart Cities ◽  
Moran’S I ◽  
Moran's I ◽  
Urban Planner ◽  
Universal Feature ◽  
Autocorrelation Method ◽  
Selection Of

From earliest cities to the present, spatial division into residential zones and neighbourhoods is the universal feature of urban areas. This study explored issue of measuring neighbourhoods through spatial autocorrelation method based on Moran's I index in respect of achieving to best neighbourhoods' model for forming cities smarter. The research carried out by selection of 35 neighbourhoods only within central part of traditional city of Kerman in Iran. The results illustrate, 75% of neighbourhoods' area in the inner city of Kerman had clustered pattern, and it shows reduction in Moran's index is associated with disproportional distribution of density and increasing in Moran's I and Z-score have monotonic relation with more dense areas and clustered pattern. It may be more efficient for urban planner to focus on spatial autocorrelation to foster neighbourhood cohesion rather than emphasis on suburban area. It is recommended characteristics of historic neighbourhoods can be successfully linked to redevelopment plans toward making city smarter, and also people's quality of life can be related to the way that neighbourhoods' patterns are defined. 

scholarly journals Rainwater Harvesting Potentials in Commercial Buildings in Dhaka: Reliability and Economic Analysis

Hydrology ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 9
Author(s):  
Md. Rezaul Karim ◽  
B. M. Sadman Sakib ◽  
Sk. Sadman Sakib ◽  
Monzur Alam Imteaz
Keyword(s):  
Water Demand ◽  
Rainwater Harvesting ◽  
Economic Benefits ◽  
Commercial Buildings ◽  
Environmental Benefits ◽  
Capital City ◽  
Balance Model ◽  
Climate Conditions ◽  
Rainwater Tank ◽  
Catchment Areas

Despite numerous studies on residential rainwater tank, studies on commercial rainwater tank are scarce. Corporate authorities pay little heed on this sustainable feature. With the aim of encouraging corporate authorities, this study presents the feasibility and economic benefits of rainwater harvesting (RWH) in commercial buildings in the capital city of Bangladesh, where water authority struggles to maintain town water supply. The analysis was conducted using a daily water balance model under three climate scenarios (wet, dry and normal year) for five commercial buildings having catchment areas varying from 315 to 776 m2 and the storage tank capacity varying from 100 to 600 m3. It was found that for a water demand of 30 L per capita per day (lpcd), about 11% to 19% and 16% to 26.80% of the annual water demand can be supplemented by rainwater harvesting under the normal year and wet year climate conditions, respectively. The payback periods are found to be very short, only 2.25 to 3.75 years and benefit–cost (B/C) ratios are more than 1.0, even for building having the smallest catchment area (i.e., 315 m2) and no significant overflow would occur during monsoon, which leads to both economic and environmental benefits. Though the findings cannot be translated to other cities as those are dependent on factors like water price, interest rate, rainfall amount and pattern, however other cities having significant rainfall amounts should conduct similar studies to expedite implementations of widescale rainwater harvesting.

Selecting Sanitation Solutions for Peri-urban Areas: A Case Study of Can Tho, Vietnam

2010 ◽  
Vol 5 (4) ◽  
Author(s):  
Naomi Carrard ◽  
Juliet Willetts ◽  
Cynthia Mitchell ◽  
Mick Paddon ◽  
Monique Retamal
Keyword(s):  
Urban Areas ◽  
Cost Effective ◽  
Asset Replacement ◽  
Fit For Purpose ◽  
Infrastructure Investments ◽  
Sanitation Systems ◽  
Can Tho City ◽  
Sustainable Futures ◽  
Sanitation Infrastructure ◽  
Selection Of

In peri-urban areas where infrastructure investments have not yet been made, there is a need to determine the most context-appropriate, fit for purpose and sustainable sanitation solutions. Decision makers must identify the optimal system scale (on the spectrum from centralized to community to cluster scale) and assess the long-term costs and socio-economic/environmental impacts associated with different options. Addressing both cost-effectiveness and sustainability are essential to ensure that institutions and communities are able to continue to bear the costs and management burden of infrastructure operation, maintenance and asset replacement. This paper describes an approach to sanitation planning currently being undertaken as a research study in Can Tho City in southern Vietnam, by the Institute for Sustainable Futures and Can Tho University in collaboration with Can Tho Water Supply and Sewerage Company. The aim of the study is to facilitate selection of the most context-appropriate, fit for purpose, cost effective and sustainable sanitation infrastructure solution. As such, the study compares a range of sanitation alternatives including centralized, decentralized (at household or cluster scale) and resource recovery options. This paper provides an overview of the study and considers aspects of the Can Tho and Vietnamese regulatory, development and institutional context that present drivers and challenges for comparison of options and selection of fit for purpose sanitation systems.

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