Handbook of Water Harvesting and Conservation

Case Studies and Application Examples

Saeid Eslamian, Faezeh Eslamian, Saeid Eslamian, Faezeh Eslamian

• Publisher: Wiley-Blackwell
• Year: 2021
• Print ISBN: 9781119775980
• eBook ISBN: 9781119776000
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Environmental Management
• Index: Technology & Engineering

Water harvesting is gaining more and more recognition asthesustainableand resilientalternative to other water supply options. It is economically viable, socially compatible and environmentally friendly. Water harvesting has proven to be arobustsolution to overcome or reduce water shortages all over the world. To apply this in a sustainable and effective way, it is important to understand exactly where it can be applied to make full use of its potential.

TheHandbook of Water Harvesting and Conservation: Case Studies and Application Examples is the mostcomprehensive, up-to-dateand appliedcasebook on water harvesting and conservation yet published.The editors bring together the many perspectives into a synthesis that is both academically-based and practical in its potential applications.

TheHandbook of Water Harvesting and Conservation: Case Studies and Application Examples will be an important tool for education, research and technical works in thesoil, waterand watershedmanagement area, and will be highly useful for drought strategy planning, flood management and adaptation to climate changein all urban, agricultural, forest, rangelandareas.

Part I
Introduction

1
Feasibility Study of Rainwater Harvesting Systems

Ramaswamy Sakthivadivel and Soorya Vennila

Centre for Water Resources, Anna University, CEG campus, Chennai, India

1.1 Introduction to Rainwater Harvesting Systems

Rainwater harvesting (RWH) and utilization systems have been in use since early Roman times, dating back to 2000BCE (GRDC 2002). Archeological evidence in Israel confirms early RWH; ruins of cisterns built to store runoff water from rainwater harvesting from hillsides for agricultural and domestic use are standing there even today. Any rainwater harvesting system requires many components to meet its objective of construction and use. These components are site specific and are governed by the use to which harvested water is to be put. Also, it is governed by the feasibility of technical, economic, environmental, and socio‐cultural factors. However, there are five main water harvesting components that are essential to have in a rainwater harvesting system. They are: collection area, conveyance system, flush filter diverter, leaf screen, and water storage tanks. The technology also has a long history in Asia, where rainwater collection practices have been traced back almost 2000 years in Thailand and over 4000 years in India (Jainer 2016). Rainwater harvesting systems are increasingly being used due to increase in population, water scarcity, and groundwater pollution both in developed and developing countries. It is used in rural and urban areas for potable and non‐potable water use. It is used in all climatic zones – arid, semiarid, and humid – and used by rich and poor people. Rich people use it to have water security and to minimize the cost of water, energy, and drainage. Poor people go for it because of its cost effectiveness and simple technology.

Farmers use this technology for supplementary irrigation to increase their crop productivity and for their livestock feeding. It is used in schools, hospitals, individual households, and industries to meet their water requirement in a sustainable way, both singly or in combination with other sources. RWH is one of the quickest and easiest ways to reduce water consumption from outside sources and is an easy and efficient way of meeting water requirements. The best thing about harvested rainwater from rooftops is that in most cases, it is free from pollutants as well as salts, minerals, and other natural or man‐made contaminants. In the areas where there is excess rainfall, the surplus harvested rainwater can be used to recharge groundwater through artificial recharge techniques, which will result in stabilizing groundwater levels. RWH is an effective and eco‐friendly method of reducing water usage in dwellings, which will lead to reduce water bills. RWH systems require comparatively little maintenance, time, and energy to do the cleaning. RWH is a low‐cost maintenance system, provides a supply of safe water to homes close by, as well as schools or clinics, encourages increased consumption, reduces time women and children spend collecting water, and will reduce back strain or injuries from carrying heavy water containers. The RWH system is independent and therefore suitable for scattered settlements. In places where groundwater is saline, or ground and surface water are not available, RWH will be the most preferred, cost‐effective, and affordable system. Some of the disadvantages of RWH include the fact that rainfall is hard to predict, and sometimes little or no rainfall can limit the adoption of RWH system and make it unsustainable. Depending on the system size and technology level, the initial cost of the system may be high compared to tap water systems. RWH systems can act as a breeding ground for disease vectors if they are not properly maintained.

The feasibility of RWH systems is carried out to determine the viability of using rainwater for drinking, domestic water, water for livestock, water for gardening and irrigation, and a way to replenish groundwater; to meet the increasing water demand; to overcome water shortage from an existing source and stabilize water supply; to conserve and augment the storage of groundwater; a potential alternative source to overcome groundwater quality problems such as arsenic, fluoride, and hardness; as a supplementary source to mature crops as well as to increase crop productivity; to overcome extreme conditions of drought, flooding, soil erosion, sea water intrusion, waterlogging etc.; and to minimize the cost of water, energy, and drainage bills.

1.2 Review of Literature on Feasibility of Rainwater Harvesting Systems

The published literature contains hundreds of studies on feasibility of RWH systems. Many of them are site specific and cover limited aspects of feasibility of the RWH system. To give a glimpse of feasibility studies carried out so far, a few studies covering different aspects are presented in this section.

Xiao (2008) argues that RWH systems are financially attractive to Beijing farmers who are mainly using underground water in the rural areas of Beijing for crop production. The present rate of subsidy to RWH systems did not give any extra benefit over that of conventional irrigation, and as such Beijing farmers are not interested in adopting RWH systems. Increasing subsidies and/or using RWH system tanks during the dry season for different purposes such as mushroom growing will make RWH more attractive to Beijing farmers. In assessing the technical feasibility of RWH systems in Chennai, India, KRG Rainwater Foundation (2010) suggests that survey relating to geology and structural control, hydrogeological survey, well inventory, geophysical survey with vertical electrical sounding, sources of water supply, existing surface water bodies, and drainage system should form part of the feasibility study to conduct a water balance analysis and to assess the RWH potential.

Alam et al. (2012) argues that in heavy rainfall areas such as Sylhet city and suburban areas in Bangladesh, the feasibility of RWH system adoption exists in rural communities and thickly populated urban areas using low‐cost technology based on quantity of rainfall runoff. According to them, a carefully planned use of rainwater through RWH system in the roof catchments may fulfill the entire annual domestic water demand of a family in the rural areas of Bangladesh. The Food and Agriculture Organization (FAO 2014), based on a feasibility study conducted on rainwater harvesting for agriculture in th...

Table of contents

• Cover
• Table of Contents
• Title Page
• Copyright
• Preface
• About the Editors
• List of Contributors
• Part I: Introduction
• Part II: Ancient Water Harvesting and Management
• Part III: World Evolution of Small‐Scale Rainwater Harvesting
• Part IV: Freshwater Conservation, Recharge, and Water Harvesting in Africa
• Part V: Rainwater Harvesting and Hydroelectric in the Americas
• Part VI: Asian Rainwater Harvesting and Conservation Examples and Policy Issues
• Part VII: Rainwater Harvesting in Europe: Technical, Social, Economic, and Political Issues
• Index
• End User License Agreement