HEALTH AND SANITATION
Innovative smart phone app to
improve rainwater harvesting in Africa
37
By
UN Environment Programme, edited by Eamonn Ryan
It is now possible to calculate the amount of rainwater that can be harvested from
the roof of houses thanks to a new smart phone app developed by UN Environment
and the United Nations Educational, Scientific and Cultural Organisation.
The app, a first of its kind, is based on actual
meteorological data collected from weather stations
across Africa. The data is specific to locations closest
to the weather stations, which the app presents as the
nearest city.
Promoting rainwater harvesting is becoming increasingly
important to ensure greater water security. It offers an adaptation
strategy to climate change, providing an opportunity to store
rainwater under increasing conditions of high rainfall variability.
It can improve household sanitation and health with an improved
drinking water source. Rainwater harvesting also contributes to
food security, providing water during dry seasons for smallscale
agriculture. Although not every single drop of rain can and
should be harvested, rainwater is still an underutilised water
source in Africa.
The lack of water is a real challenge across Africa. On average,
a person needs eight glasses of water (2l) per day. According
to the Vital Water Graphics report by UN Environment and GRID
Arendal, “more than 2.8 billion people in 48 countries will face
water stress or water scarcity conditions by 2025. An area is
experiencing water stress when annual water supplies drop below
1 700m 3 per person”.
In many such countries, rainwater can be harnessed easily for
domestic and agricultural use. Harvested rainwater can also
benefit the environment and ecosystem when used to enhance
groundwater recharge and restore vegetative cover. The low cost
of rainwater harvesting technologies can be a more attractive
investment option in rural areas compared to investing in a main
water supply system.
“This app is practical for individuals as well as communities,
local governments, and other actors who are planning to
install rainwater harvesting systems in Africa,” said Dr Juliette
Biao, Director of Africa Office in UN Environment. “The app
is a concrete example of how science and innovation can be
packaged to solve day-to-day needs of households in Africa,”
she adds.
The new app demonstrates opportunities for rainwater harvesting.
For example, a person in Turkana county in Kenya can enter
her location (Kenya, Lodwar), the length and width of the roof of
Medium.com
the house (in metres), the number of family members, and the
quantity of water used per day. The app returns the estimated
amount of rainwater that can be harvested, and the quantity
of water for a family. It also proposes the size of the rainwater
harvesting system as well as its estimated cost. Simple sketches
showing rainwater systems and how to recharge groundwater
are also included in the app. Rainwater harvesting systems can
be easily constructed using appropriate technology and locally
available materials.
Rainwater can be collected in relatively simple ways. Rainwater
that falls in ditches, on rooftops or on other surface areas is
collected in storage facilities, such as water tanks or ponds. This
water is stored and used for domestic and agricultural purposes.
There are also other ways of rainwater harvesting, such as storing
it in the ground where it can be used as groundwater for human
consumption or for nature.
Ann Kiria, chair of a young women's group in Kajiado in Kenya
says, “Water harvesting has benefitted our community where
women have played a key role in constructing water tanks. With
the knowledge we have acquired, building a water tank to harvest
rainwater is no more out of reach”.
Currently the smart phone application is available for Android
(Play Store) system for free. It can be downloaded by searching
for RWH Africa Interactive Tool.
Reference:
1. https://www.unenvironment.org/news-and-stories/story/
innovative-smart-phone-app-improve-rainwater-harvestingafrica
PA
Frida Emria, a
community health
volunteer at the
dispensary in
Mogila village
near Lokichogio,
Turkana, Kenya.
September 2020 Volume 26 I Number 07
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