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Water Harvesting Tool

Water is a scarce and valuable resource. It is a vital part of daily life for good health, comfort and well-being! A cold glass of clear, fresh water is the very picture of a healthy, vibrant lifestyle! However, as population growth, urbanisation, pollution, industrialisation and other pressures increase demands on central water supplies this cold, clear glass is a picture that many are not able to enjoy.

Every rain storm delivers millions of litres of water that can be “harvested” to help alleviate pressure on centralised water collection, reduce costs of water supply or where centralised alternatives are not available become the main source of supply. However, harvesting water requires careful thought and good design.

The WRC CSAG Water Harvester Tool will help you step through the process and work through design options!

We all know that some years are dry and some wet! That range in rainfall is captured in the climate record. We use rainfall data for the Southern African region to carry out calculations of water balance of a water harvesting system. These calculations are location-specific (i.e. use rainfall for a user-selected location), and utilize user-defined system’s design parameters. This allows to :

  • evaluate how do the water harvesting system’s design parameters determine the amount of water that could be obtained from it,
  • compare water supplied from water harvesting system relate with the user’s water demand (or actual use) pattern,
  • visualize what can one expect from the water harvesting system in average, dry and wet years,
  • assess various design option to cope with year-to-year and seasonal climate variability and to improve system’s performance.

What can you find here?

The focus of the Water Harvester tool is on those aspects of water harvesting system’s design that affect how much water does the system provide, i.e. on roof area, tank volume and first flush diverter. The design of the water harvesting system does, however, involve several other elements, such as appropriate gutters, plumbing, filters etc, and its operation should be carried out with care, knowledge and understanding in order to provide safe (clean) water. Here, however, we only highlight the key elements of the design and operation of a roof-top harvesting system, and do not explore them in depth. There is a wealth of information on those aspects of water harvesting elsewhere on internet, conveniently provided by commercial and non-profit organizations. Please use those sources too, before you decide whether or not to implement a particular design of a water harvesting system in your house/farm/context