Draft
1.0 Introduction
In communities and rural areas where there is no surface water, where groundwater is deep or too salty, acidic or is generally unpleasant to drink, another source of clean water must be sought. In areas that experience regular rainfall and the least air pollution, the most sustainable and appropriate alternative is the collection of rainwater rather than allowing it to run off. Usually called “rainwater harvesting”.
This report will consider the way in which the harvesting of rainwater for its later re-use on site offers greater benefits than other sustainable options in given areas and communities. As falling rain can provide some of the cleanest naturally occurring water that is available anywhere, which is why using this method makes obtaining drinkable water quick, cheap and simple. The sustainability, cost and importance as well as techniques used will be examined and the role of rainwater harvesting in preventing flooding, erosion and storm water pollution will be outlined.
2.0 Background
Water is a basic human essential for maintaining life, without it, no civilization could have prospered. Humans have used the stored water differently in different times, anciently to irrigate crops in hotter climes and as a tool of survival during war, present-day to combat climate change.
2.1 Ancient use
The long history of rainwater harvesting can be traced back to as far as ancient times, some 3000 years ago (850 BC), if not even farther. In ancient Egyptian warfare, the army would use the desert to their advantage, because they had large amounts of harvested rainwater stored throughout the desert in underground tanks carved out of solid rock. And in the ancient cities of Indus Valley, cisterns were used to store rainwater for dryer times in order to keep the local population and vegetation alive through dryer times.
2.2 Modern Rainwater harvesting
Over the last few centuries, the need to store water was no longer essential because of increased urbanization. However, as a result of prolonged drier periods caused by climate change, we are once again returning to this ancient and crucial part of greener living.
3.0 Harvesting Rainwater as a solution
3.1 How it works
3.1.1 Installation
Rainwater harvesting systems can range in complexity, from systems that can be easily fitted to existing homes with minimal skills, to systems that are only suitable for new-builds and require advanced setup, because of the large internal plumbing work required. The latter being more capable and pricey.
Catchment Tube: Necessary pipes are installed to channel the rainwater to the underground tanks
First Flush system: All capture points of where the rainwater exits the gutters will have a First Flush system installed. This system captures the first several liters of dirty rainwater from your roof from the beginning of the rainfall and it diverts it away from your rain tank, making way for only the cleaner rainwater to enter the rain tank.
Tank: The tank is carefully placed on foundations that are a few inches underground.
Overflow: When the tank fills with rainwater, it has an exit point to leave safely without causing erosion problems on the ground.
Pump: A pump is fitted with the system if the target area where rainwater is need is above the tank.
Figure 1.1 (“Residential Rainwater Harvesting System Ready to Install In the Eco-$Mart Catalog”)
3.1.2 Process of Water Collection
All rainwater harvesting systems work using traditional roof drainage designs. This means that the buildings share of rainfall runs down the roof, into the guttering and down the pipes before passing through a filter, which removes the leaves and debris. The collected rainwater is later stored in underground cisterns fitted with pumps and heaters.
Figure 1.0 (“Rainwater Harvesting System Rebate – City Of Guelph”)
3.1.3 Using the Harvested water
The collected rainwater can be later used for gardens, irrigation and livestock. Gardens alone can consume up to 50% of peak demand in the summer, so keen gardeners that harvest rainwater could save thousands of litres of tap water each year. The collected rainwater can be consumed without treatment, as long as a clean collecting surface has been used.
3.1.4 Maintenance
Poorly structured rain containers can suffer from algae growth and invasion by insects, lizards and rodents. They can act as a breeding ground for disease vectors if they are not properly maintained.
4.0 Greener Environment
4.1 Storm water pollution
4.2 Erosion
5.0 Using the Weather to pay your bills
5.1 Feasibility by region
6.0 Cost
6.1 Installation
6.2 Maintenance