By Maile Matsimela
Water is an essential resource in farming, whether for livestock, irrigation or processing of crops, or fish farming. To use water efficiently, it has to be stored in tanks or reservoirs, depending on its intended use. But the cost of constructing reservoirs for water storage can be a significant portion of the overall infrastructure investment on a farm.
It is well known that the conventional round concrete farm dam is a reliable, durable reservoir, but it is expensive and labour-intensive to build. To provide farmers with a more affordable water-storage solution, ARC Agricultural Engineering explored a cost-effective alternative. A DIY reservoir was erected and its durability was evaluated for a period of three years.
S.P.R. Vorster, a professional engineer at ARC Natural Resources and Engineering, published this DIY information in the July 2022 issue of AgriAbout, a free monthly digital magazine offering information on the latest trends and practices in sustainable agriculture.
The experimental dam was exposed to all weather conditions, and typical usage was simulated by using the water stored in it to irrigate a vegetable plot. It was emptied, refilled and cleaned regularly. The verdict? “The reservoir fulfilled its purpose during the evaluation period.”
Widely available materials
Erecting this DIY reservoir costs less than what it would cost to build a round concrete dam, and less than a quarter of the price of installing a prefabricated concrete dam.
The round structure is constructed out of welded wire mesh, lined on the inside with polyester cloth coated with a waterproofing substance. It is reinforced by a series of treated timber poles, which are set into the ground in a circular formation of the required diameter. The wire mesh is secured to the inside of these vertical poles.
Vorster says the dam’s construction is straightforward. The materials are widely available, easy to work with, and require no specialised knowledge or equipment.
The reservoir does require regular maintenance due to normal wear and tear. It is also susceptible to mechanical damage, and should be fenced off to protect it from animals.
Different sizes
It is possible to construct a reservoir ranging in size from 10 m3 to 100 m3 based on its intended use. The ideal size will depend on various factors:
1. The reservoir’s purpose
2. How often water will be pumped into it
3. Total water consumption during that timeframe
4. The reliability of the water source
5. The potential damage of water shortages in the absence of storage
A manual on how to erect the dam is available from the ARC Agricultural Engineering campus (email stolze@arc.agric.za). For further enquiries, email S.P.R. Vorster at vorsters@arc.agric.za.
