Tales from a Sustainable Construction Site: the Bucket and the Hose.

Reading time: 2 min.

In development construction projects, there are often a number of risks to be considered. Today we’re going to talk about risks associated with the construction itself, rather than topics such as security which may surround any project.

Availability of resources, both in terms of materials as well as tools and specialist labour, can affect what is achievable. Assuming all resources are in place, however, there is also the question of the terrain itself.
Marginalised populations are often driven away from more desirable grounds, which are otherwise ripe for agricultural activities or more expensive housing. Often, what is left is unstable ground which many governmental agencies would declare unfit for construction.
Informal settlements comprised of shanties or shacks, otherwise known as Shanty towns, are typically made of materials like mud or wood and can be found on steep hillsides. They exist across the world – with some of the largest being Ciudad Neza in Mexico, Orangi in Pakistan and Dharavi in India, as well as in the Global North, such as in Athens, Los Angeles, and Madrid.
They can be places of hope, with residents often recycling as much as possible and aiming to improve their communities. Indeed, many manage to improve their infrastructure and become more typical neighbourhoods.

Construction projects in these areas very often need to take steep gradients into account. Sometimes due to inadequate budgets or lack of advanced measurement tools, it is hard to get exact information of how sloped the terrain actually is. And that data is crucial to start any kind of design. In our first project in Ghana (Darmang Community School), we were faced with the same challenge and used an ancient technique to help us out. The method is easily taught, and as it involves simple and readily-available tools can be used in future projects as well.

All you need is… a bucket and a hose!

Measuring a slope requires a few steps, and some simple mathematics.

  1. A hose is laid along the length of the slope to be measured (which we will name “a”)
  2. Water is slowly poured into hose at the higher end
  3. At the lower end, the hose is slowly raised (a ladder can be useful) until water is no longer coming out of the hose. This means that both ends have the same water level. The distance from the ground to the top of the raised slope is measured (this is “b”)
  4. We use the formula: sinA = a / b
  5. Remember not to get too wet!
The final Result: Darmang Community School. More info here.

Author: David Jenkins