Development and Simulation of Decentralised Water and Energy Supply Concepts – Case Study of Rainwater Harvesting at the Angkor Centre for Conservation of Biodiversity in Cambodia

Besides a sufficient energy supply, concepts for accommodations require an intelligent water management. Using the example of quarters that do not have water and energy access, a dynamic simulation model is presented in which a rainwater harvesting concept is implemented and simulated over one year using MATLAB-Simulink. The aim is to minimize respectively suspend the use of fossil energy sources and to guarantee the provision of decentralized clean drinking water. Since traditional water bodies, e.g. groundwater, are increasingly polluted and depleted, utilisation of alternative sources is prudent. Especially in rural areas, where access to drinking water is scarce, rainwater is suitable for providing potable water. Besides its beneficial chemical water properties, it is easily accessed in a decentralized manner, which makes it a preferred choice in areas with sufficient precipitation. However, access to rainwater is limited by its occurrence and contamination, calling for proper storage, utilisation, and treatment strategies. For this purpose, a rainwater harvesting system, including different water and energy management systems, was modelled and implemented using the site of the Angkor Centre for Conservation of Biodiversity in Cambodia as an example. For the simulation, a precipitation generator was implemented using real historical rain event data. An appropriate rainwater treatment process was chosen, consisting of a microfiltration and a subsequent ultrafiltration unit removing bacteriological loads entirely. Both were modelled and implemented dynamically. Using the site of the Angkor Centre of Conservation of Biodiversity, a complete rainwater harvesting plant was implemented including harvest, storage, and utilization of rainwater. Further, a renewable energy management strategy is developed, using photovoltaic modules and batteries. It was shown that the cumulative runoff meets the water demand of the Angkor Centre for Conservation of Biodiversity and that the energy demand of the rainwater system as well as the site can be met by the installed photovoltaics on the existing roof area

Implementation of a non-parametric rainfall simulation method to size rainwater harvesting systems for stormwater management and irrigation of urban agricultural facilities

Combined Sewer Overflows (CSOs) are one of the biggest problems associated with stormwater runoff in Philadelphia. Rainwater harvesting (RWH) for the purpose of storage and non-potable reuse is one of several highly advocated solutions for reduction of stormwater runoff especially in urban areas. Various RWH systems have been designed based on simple supply vs. demand water balance concepts and somewhat more complex parametric rainfall simulation methods.This project involves the use of a non-parametric rainfall simulation method incorporated in the Storage and Reliability Estimation Tool (SARET) developed by Basinger, Montalto, & Lall (2010) to size a RWH system collecting stormwater runoff from residential roofs at an urban agricultural facility situated at 53rd and Wyalusing Avenue, Philadelphia. Two methods were used to obtain the irrigation requirements for the urban agricultural facility, one uses the Blaney-Criddle method (Blaney & Criddle, 1950) while the second uses water consumption bills obtained at the site. SARET then uses historical daily precipitation data for Philadelphia to develop storage vs. catchment area reliability curves based on which the desired volume of the storage facility as well as the catchment area are chosen. During the design phase, a bioretention facility was preferred as a treatment facility to improve the water quality of runoff collected from the roofs before application to the crops. Analyzing various options, StormChamber® developed by Hydrologic Solutions was chosen as a underground water storage facility. The specifications and construction plans for the bioretention facility, storage facility and other aspects of the system were then laid out to enable the final construction.Once the construction was complete, a preliminary assessment was performed by estimating the depth vs. volume relationship of the storage facility and conducting a statistical test on the observed data, based on which it was concluded tentatively that the system was working as designed. A more in depth analysis, based on a longer observation period is, however, required for a more conclusive assessment. Finally, a GIS analysis was performed using planimetrics data in ArcGIS 10.1 that looks at other residential sites within Philadelphia where a similar system can be replicated consisting of both the RWH system as well as the agricultural facility.M.S., Environmental Engineering -- Drexel University, 201

Application of Climatic Data in Hydrologic Models

Over the past few decades, global warming and climate change have impacted the hydrologic cycle. Many models have been developed to simulate hydrologic processes. Obtaining accurate climatic data on local/meso, and global scales is essential for the realistic simulation of hydrologic processes. However, the limited availability of climatic data often poses a challenge to hydrologic modeling efforts. Hydrologic science is currently undergoing a revolution in which the field is being transformed by the multitude of newly available data streams. Historically, hydrologic models that have been developed to answer basic questions about the rainfall–runoff relationship, surface water, and groundwater storage/fluxes, land–atmosphere interactions, have been optimized for previously data-limited conditions. With the advent of remote sensing technologies and increased computational resources, the environment for water cycle researchers has fundamentally changed to one where there is now a flood of spatially distributed and time-dependent data. The bias in the climatic data is propagated through models and can yield estimation errors. Therefore, the bias in climatic data should be removed before their use in hydrologic models. Climatic data have been a core component of the science of hydrology. Their intrinsic role in understanding and managing water resources and developing sound water policies dictates their vital importance. This book aims to present recent advances concerning climatic data and their applications in hydrologic models

Multivariate and multi-scale generator based on non-parametric stochastic algorithms

A method for generating combined multivariate time series at multiple locations and at different time scales is presented. The procedure is based on three steps: first, the Monte Carlo method generation of data with statistical properties as close as possible to the observed series; second, the rearrangement of the order of simulated data in the series to achieve target correlations; and third, the permutation of series for correlation adjustment between consecutive years. The method is non-parametric and retains, to a satisfactory degree, the properties of the observed time series at the selected simulation time scale and at coarser time scales. The new approach is tested on two case studies, where it is applied to the log-transformed streamflow and precipitation at weekly and monthly time scales. Special attention is given to the extrapolation of non-parametric cumulative frequency distributions in their tail zones. The results show a good agreement of stochastic properties between the simulated and observed data. For example, for one of the case studies, the average relative errors of the observed and simulated weekly precipitation and streamflow statistics (up to skewness coefficient) are in the range of 0.1–9.2% and 0–5.4%, respectively.This is the submitted version of the article: Đ. Marković, S. Ilić, D. Pavlović, J. Plavšić, and N. Ilich, ‘Multivariate and multi-scale generator based on non-parametric stochastic algorithms’, Journal of Hydroinformatics, vol. 21, no. 6, pp. 1102–1117, Nov. 2019, [https://doi.org/10.2166/hydro.2019.071

Development of Integrated Water Resources Planning Model for Dublin using WEAP21

Population growth, urbanisation, and climate change are predicted to impose huge pressure on water resource systems of many cities around the world including Dublin. Integrated water resources management is seen as a viable approach to address these challenges. This approach examines the water resources system in a more interconnected manner, focusing on reducing water demands, reducing reliance on fresh water supplies, reducing discharges into receiving water bodies, and creating water supply assets from storm water and wastewater. The role of mathematical modelling in designing an integrated water resources management plan is paramount as it provides a tool whereby performances of alternative water management plans can be predicted and evaluated under future scenarios of population growth, urban development and climate. There is a lack of an integrated water resources management model for Dublin that integrates the main components of the water resources system including water supply sources, sectoral water uses, wastewater disposal, urban runoff and associated infrastructure. Previous models also did not consider water management options such as rainwater harvesting, greywater reuse, and groundwater recharge - which are important for the implementation of an integrated water resources management approach. Moreover, integration of uncertainty analysis into water resources modelling helps understand associated uncertainties and hence reduce the

Land Cover and Climate Change Impact on River Discharge: Case Study of Upper Citarum River Basin

The Upper Citarum River Basin is the main catchment area of the Saguling Dam, the most upstream of three cascade dams in the Citarum River Basin. During the last 30 years, rapid economic development has led to an increase of water extraction and land conversion from green area to developed area. Also, evidence of climate change can clearly be seen from the climatological records of a number of climatology stations in this basin over the last few decades. In this study, the effect of anthropogenic and climate change in the Upper Citarum River Basin river discharge was simulated using the Sacramento Catchment Model. Historical river discharge, rainfall, climatology, and land cover from 1995 to 2009 were used for model calibration and verification. The multi-model mean monthly rainfall and the temperature projection taken from Coupled Model Intercomparison Project 5 (CMIP5) for the RCP6 and RCP8.5 climate change scenarios were statistically downscaled and used as input for a simulation of future river discharge from 2030 to 2050. The result showed that the combination of anthropogenic and climate change may result in a significant decrease of low flow in the Upper Citarum River Basin. This study underlines the importance of land cover and climate change factors for future infrastructure planning and management in the Upper Citarum River Basin

Dual-duty rainwater harvesting: water supply and urban stream restoration

An exciting epoch is before us where we are focused on transforming urban living to a higher symbiosis with nature. For now, and looking over the immediate horizon, the pursuit is for water sensitive cities with green spaces which encourage a modern lifestyle that is considerate of, connected with and dependent on the natural environment. Practical realisation of this vision is perpetuated by innovations in water sensitive urban design (WSUD). The main objective is to capture, treat and use stormwater at its source, of which rainwater harvesting is fundamental. Rainwater harvesting is well-known as a decentralised water supply alternative or supplement to the centralised water supply services of municipalities. The majority of design and assessment of rainwater tanks is focused on the reliability of supply. Additionally, rainwater tanks can significantly improve urban hydrology by capturing, consuming and effectively removing excess urban runoff. In this dissertation, a new approach is introduced to assess the combined outcomes of rainwater tanks. Dual-duty rainwater tanks are designed to restore degraded aspects of urban hydrology which stream ecosystems are particularly vulnerable to, while providing an alternate water supply. The dual-duty performance framework is applied to examine the implications of enabling environmental flows from rainwater tanks. Research questions are explored: will environmental flows improve dual-duty performance; are adaptive approaches for managing environmental flow superior to a fixed leaking approach; to what extent do environmental flows diminish water supply; can rainwater tanks significantly improve urban stream hydrology in isolation to WSUD or other stormwater management initiatives; and what are the realistic expectations of dual-duty performance across the spectrum of urban residential living in Australia. To answer these questions, a mass-balance rainwater tank simulator UrbanTank © was created and alternate storage arrangements and operating conditions were studied including the conventional tank, where the sole purpose is to supply rainwater to households and environmental flows do not occur; the leaking tank, which trickle-releases environmental flow from a virtual chamber of fixed volume; and the adaptive tank where environmental flow storage is actively regulated by the severity of rainfall statistics, rainfall forecasts and/or a combination of both controls. Also, to qualify simulation results outdoor water use was linked to climatic indices of daily rainfall and daily maximum temperature. Rainwater yield estimates were verified by independent field measurements, simulation and statistical analyses throughout Australia. To allow a comparative assessment of all tank alternatives, a method was developed to supplement the limited duration of rainfall forecast archives. The results demonstrate environmental flows, regardless of the method of operation, significantly improved dual-duty performance; the increasing complexity of adaptive approaches for managing environmental flows was not justified by a significant improvement in dual-duty performance over the simpler leaking tank arrangement; when enabling environmental flows the water supply independence dropped by a marginal 2% while the environmental benefits increased by 33%; the leaking tank was able to achieve on average a 90% compliance with natural hydrology measured by a simplified version of the environmental benefit index, which demonstrates rainwater tank can be used in isolation to WSUD or other stormwater management initiatives; and results from leaking tanks are encouraging over the breadth of simulation scenarios studied. The dissertation concludes by establishing a relationship between dimensionless fractions and the key performance metrics of supply independence and environmental benefit index. These relationships facilitate rapid assessment of the dual-duty performance of conventional and leaking rainwater tanks across the spectrum of urban residential living. Rapid estimates are based on rainfall statistics, which can be potentially determined at any location in Australia and for similar climates elsewhere; and the scope of parameters studied which comprise roof area (100 m2 to 200 m2), tank volume (2.5 kL to 7.5 kL) and annual rainwater demand (44 kL/y to 176 kL/y). This dissertation has introduced a dual-duty framework for the design and assessment of rainwater tanks with a focus on minimising the degradation and demand municipalities place on contiguous water resources. These contributions to research have broadening our scientific knowledge and it is hoped the outcomes will expedite the promotion of water sensitive cities

Pluvial flooding: high-resolution stochastic hazard mapping in urban areas by using fast-processing DEM-based algorithms

Climate change and rapid expansion of urban areas are expected to increase pluvial flood hazard and risk in the near future, and particularly so in large developed areas and cities. Therefore, large-scale and high-resolution pluvial flood hazard mapping is required to identify hotspots where mitigation measures may be applied to reduce flood risk. Depressions or low points in urban areas where runoff volumes can be stored are prone to pluvial flooding. The standard approach based on estimating synthetic design hyetographs assumes, in a given depression, that the T-year design storm generates the T-year pluvial flood. In addition, urban areas usually include several depressions even linked or nested that would require distinct design hyetographs instead of using a unique synthetic design storm. In this paper, a stochastic methodology is proposed to address the limitations of this standard approach, developing large-scale ~ 2 m-resolution pluvial flood hazard maps in urban areas with multiple depressions. The authors present an application of the proposed approach to the city of Pamplona in Spain (68.26 km2)

Impacts of Climate Change on Rainfall Extremes and Urban Drainage Systems

Impacts of Climate Change on Rainfall Extremes and Urban Drainage Systems provides a state-of-the-art overview of existing methodologies and relevant results related to the assessment of the climate change impacts on urban rainfall extremes as well as on urban hydrology and hydraulics. This overview focuses mainly on several difficulties and limitations regarding the current methods and discusses various issues and challenges facing the research community in dealing with the climate change impact assessment and adaptation for urban drainage infrastructure design and managemen