Extreme Floods, the Key to Climate Change Adaptation in Africa’s Drylands

A borehole in Kenya’s Turkana County. Experts say that
groundwater in drylands is recharged through extreme floods.
Credit: Isaiah Esipisu/IPS

By Isaiah Esipisu
TURKANA COUNTY, Kenya, Aug 8 2019 (IPS)

Extreme rainfall and heavy flooding, often amplified by climate
change, causes devastation among communities. But new research
published on Aug. 7 in the scientific journal Nature
reveals that these dangerous events are extremely significant in
recharging groundwater aquifers in drylands across sub-Saharan
Africa, making them important for climate change adaptation.

According to the research, which was led by the University
College London (UCL) and Cardiff University, this vital source of
water for drinking and irrigation across sub-Saharan Africa is
resilient to climate variability and change.

“Our study reveals, for the first time, how climate plays a
dominant role in controlling the process by which groundwater is
restocked,” Richard Taylor, a Professor of Hydrogeology from UCL,
told IPS. Taylor is the co-lead on the new study, which was
conducted with a consortium of 32 scientists from different
universities and institutions from Africa and beyond.

Researchers reviewed data sets of water levels from 14 wells
across the region that are not generally used by people.

“Our data-driven results imply greater resilience to climate
change than previously supposed in many locations from a
groundwater perspective and thus question, for example, the
model-driven [Intergovernmental Panel on Climate Change] IPCC
consensus that ‘Climate change is projected to reduce renewable
surface water and groundwater resources significantly in most dry
subtropical regions,’” Taylor said in a statement.

The IPCC
Fifth Assessment Report
states in contrast that “climate
change over the twenty-first century is projected to reduce
renewable surface water and groundwater resources significantly in
most dry subtropical regions, intensifying competition for water
among sectors”.

Groundwater plays a central role in sustaining water supplies
and livelihoods in sub-Saharan Africa due to its widespread
availability, generally high quality, and intrinsic ability to
buffer episodes of drought and increasing climate variability.

So the finding comes as good news for communities and
governments across Africa where livelihoods are becoming more and
more dependent on groundwater.
“In our current budget, we have allocated over Sh164 million
(1.64 million dollars) to irrigation projects, and most of the
water already being used is from boreholes,” Chris Aleta,
Kenya’s Turkana County Minister for Water and Irrigation, told
IPS.

Turkana is a pastoral county and one of the driest in Kenya.
Research has revealed that between 1977 and 2016, cattle, which is
the main source of livelihood in this county, reduced by 60
percent.

Currently thousands of households are producing horticultural
crops that are sold locally in major towns and even overseas.

“Some of us do not have a single cow to graze,” Paul Samal,
a pastoralist-turned-farmer from Kaptir Ward, Turkana County, told
IPS.

“I had over 200 goats and a herd of 50 cattle, but most of
them were consumed by the drought in 2011, and the remaining stock
was stolen in 2015,” said the father of five.
So in 2016 he began using groundwater to grow tomatoes, watermelons
and indigenous vegetables.

Kenya’s capital, Nairobi, depends heavily on groundwater to
supplement the main source from the country’s Dakaini dam, whose
recharge mainly depends on unreliable rainy seasons.

Kenya’s neighbour Tanzania will also benefit from the
findings.The country’s capital city Dodoma relies solely in
groundwater from the Makutapora well field.

According to Lister Kongola, a retired hydrologist who worked
for the government of Tanzania from 1977 to 2012, the demand for
water in Dodoma City has been rising over the years, from 20
million litres per day (l/day) in the 1970s, to 30 million l/day in
the 1980s and to the current 61 million l/day.

The World Bank estimates that at least 70 percent of over 250
million people living in southern African countries rely on
groundwater as their primary source of water for drinking,
sanitation and livelihood support through agriculture, ecosystem
health, and industrial growth.

According to scientists, understanding the nexus of climate
extremes and groundwater replenishment is vital for sustainability.
This improved understanding is also critical for producing reliable
climate change impact projections and adaptation strategies.

The new study also found that unlike drylands, where leakage
from seasonal streams, rivers and ponds replenish groundwater, in
humid areas groundwater is replenished primarily by rainfall
directly infiltrating the land surface.

“This finding is important because model-based assessments of
groundwater resources currently ignore the contribution of leaking
streams and ponds to groundwater supplies, underestimating its
renewability in drylands and resilience to climate change,” said
Dr Mark Cuthbert, a research scientist from Cardiff University.

According to Michael Arunga of World Vision, an international
humanitarian agency that sometimes supports communities during
extreme climate events, the findings are vital for spatial planning
for governments in Africa.

“The good thing is that extreme droughts and rainfall seasons
are predictable, and the patterns are the same across Africa,”
Arunga told IPS.
“These findings will therefore make it easier for governments to
draft policies for sustainable groundwater use based on
knowledge.”

Since extreme floods can easily be predicted up to nine months
in advance, the researchers say that there is a possibility of
designing schemes to enhance groundwater recharge by capturing a
portion of flood discharges via a process known as Managed Aquifer
Recharge.

According to Prof Daniel Olago, a senior lecturer at the
Department of Geology, University of Nairobi, groundwater in Africa
remains a hidden resource that has not been studied
exhaustively.

“When people want to access groundwater, they ask experts to
go out there and do a hydro-geophysical survey basically to site a
borehole without necessarily understanding the characteristics of
that particular aquifer,” he told IPS.

However, in the recent past, the United Kingdom research
councils (Natural Environment Research Council, Economic and Social
Research Council and the Engineering and Physical Sciences
Research Council), the Department for International Development
(DFID) and The Royal Society have been supporting studies that seek
to understand the potential of groundwater resources in Africa, and
how it can be used to alleviate poverty.

“Moving into the 21st century with climate change, with
growing population, with rapid growing urban centres, groundwater
is going to be very important,” said Olago.

The post
Extreme Floods, the Key to Climate Change Adaptation in Africa’s
Drylands
appeared first on Inter Press Service.

Source: FS – All – Ecology – News
Extreme Floods, the Key to Climate Change Adaptation in Africa’s Drylands