As I mentioned in my previous post, groundwater
irrigation (GWI) has a huge potential for agriculture in Africa, but is it THE
solution?
Well, let´s say it depends. According to the Food and
Agriculture Organisation of the United Nations renewable groundwater supply is
about 1,500 km3/yr in Sub-Saharan Africa (SSA) which is “more than 3 times the
per capita groundwater availability of China” (Giordano 2005: 312), where
groundwater supply has triggered a huge part of the Green Revolution. Similarly, it is suggested that GWI may trigger a
similar technological development in SSA by securing rural livelihoods and thereby
setting the basis for food production. But, the development of GWI is still
rather limited, as only 3.3% of arable land is irrigated (Villholth 2013).
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| Fig. 1: Groundwater irrigation in Ghana (Villholth and Altchenko 2016) |
However, due
to increasing rainfall variability, small-scale farmers more and more see
groundwater as a more reliable source than e.g. rainfed irrigation (Carter and Howsam 1994). GWI is giving them more control over their own groundwater
source or are part of the community, who is. But there are more benefits. Additionally,
it is available all year round, which makes it possible to grow crops independent
of rainfall patterns. This also leads to less risk on investments for other
inputs such as fertilizers or energy (Villholth 2013). Moreover, farmers
can increase their net revenues per area irrigated. So, by using GWI farmers
“significantly improved their livelihoods and employment opportunities”
(Villholth 2013 :380).
However, there are some physical limitations that limit
groundwater extraction in some areas. Firstly, the extraction of groundwater is
not always easy and like rainfall, groundwater distribution throughout Africa
is highly variable (Giordano 2005) (see figure 2). This is mainly due to
geological conditions. About 40% of SSA is dominated by Crystalline basement
rock, which shows rather low transmittivity and is therefore a limited resource
of groundwater. Groundwater from consolidated and unconsolidated rock is easier
to access, but is sometimes limited due to storing capacity of the rock
(Giordano 2005). High yields, however, can be gained from volcanic rock,
which cover only 6% of SSA. Secondly, rainfall distribution plays a vital role
in the availability of groundwater (Giordano 2005). Aquifers are connected
to surface systems or river systems and are thus dependent on precipitation
patterns throughout the year (Giordano 2005). Fossil groundwater resources play an
essential part in arid regions especially North Africa, but also parts of SSA,
as these are related to past climatic conditions and thus are not connected to
contemporary rainfall patterns (Giordano 2005). Consequently,
“groundwater´s potential for agricultural use need to focus on regional, or
even local, rather than continental scales” (Giordano 2005 :312) and thus its
potential for ensuring food security has to be considered in its spatial
context.
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| Fig. 2: Groundwater availability and GWIP (Villholth and Altchenko 2016) |
Still, GWI further
shows socio-economic limitations. GWI also increase social disparities within
the community, as some farmers can afford buying more efficient equipment, such
as motorized pumps, whereas poorer farmers or female farmers may have
difficulties acquiring those (Villholth 2013). Thus, when evaluating the benefits
of GWI one also has to “consider gender and distributional aspects” (Villholth 2013: 381). Additionally, one of the biggest constraints is the lack of capital
in most communities as more sophisticated and reliable technology may require
expertise and are quite cost-intensive (Carter and Howsam 1994). By being
dependent on subsidies or loans many farmers tend to fall in new dependency
relationships (Villholth 2013). Furthermore, in some areas of SSA
infrastructure is inadequate, e.g. electricity or roads that make it difficult
to get building materials and labour. This is also a problem for the
accessibility of markets, where crop or livestock could be sold (
Villholth 2013). Thus, in order to make famers independent, it is important to train them so that they can keep records of water quality depletion and maintenance on their own (Carter and Howsam 1994).
Villholth 2013). Thus, in order to make famers independent, it is important to train them so that they can keep records of water quality depletion and maintenance on their own (Carter and Howsam 1994).
Additionally,
intensive GWI may lead to negative impacts on the environment. Soil degradation
and salt accumulation in upper soils may lead to groundwater contamination (Villholth 2013). Moreover, extensive groundwater exploitation may also cause
conflicts with farmers and non-farmers over drinking water sources (Villholth 2013). Lastly, although GWI is more and more supported by international and
regional development policies, institutional capacities are often insufficient
and roles within the regional administration are often unclear (Villholth 2013).
Thus, for using GWI in all its potential, its inclusion in regional and
national politics is essential. Figure 2 shows the groundwater irrigation
potential (GWIP) for Africa localised on a map. It´s calculation considers five
factors discussed before that may limit actual groundwater accessibility: (1)
distance to surface water, (2) distance to market, (3) soil suitability for
agriculture, (4) drilling and pumping cost, (5) access to electricity. This
shows that the main GWI potential lies in the tropical part of SSA, especially countries
like Cameroon, Democratic Republic of Congo, parts of Nigeria, Ghana, Liberia
or Côte d´Ivoire, where water sources are already relatively abundant
(Villholth and Altchenko 2016).
To sum it up, small-scale
GWI certainly does have great potential for improving rural livelihoods,
especially making them independent from larger water suppliers and ensuring
food production in some parts of SSA. However, its accessibility varies spatially,
and thus local approaches are needed to assess its actual benefits.
Additionally, GWI may also increase social disparities, as groundwater accessibility
and maintenance may be costly. It may lead to new dependency relationships, as
farmers may rely on high loans or subsidies. Moreover, extensive GWI may also cause
ecological problems, as e.g. soil depletion or contamination of groundwater.
Thus, is important to include it into regional and national politics and do
further research on its ecological and socio-economic impacts both in order to
properly understand the possible constraints and benefits to GWI.
References
Hey! Awesome post! I really appreciate how you provided various perspectives on the social, economical, and environmental implications of GWI. I'm not sure if this applicable in small scale GWI but I've read in past literature that groundwater exploitation may be detrimental in places where the rate at which groundwater removal far exceeds the rate at which the aquifer is filled, ultimately leading to ground subsidence. Have you run into anything while doing your research on long term geological impacts?
ReplyDeleteHi Stephanie,
DeleteI agree, this is definitely a danger! I haven´t found anything specifically on small-scale GWI, but I believe it is essential to consider its geological impacts. Although one might think small-scale irrigation is still not relevent enough to have these impacts on the ground, when implementing it as a means of empowering farmers on a larger scale, its consequences will eventually become apparent in the ground. I think it also depends on the kind of groundwater aquifers. While renewable sources might recover faster and thus it may take longer until you can actually measure its impacts in the ground, fossil aquifers may be more vulnarable to ground subsidence. I guess in order to prevent large-scale and irreversible geological impacts, it is important to assess the consequences of GWI early in the process and to establish ways of sustainable groundwater extraction.
Hi! I really enjoyed reading your post on groundwater irrigation and as a source of water supply, particularly the para exploring the socio-economic limitations of groundwater. I would really like to find out more about governmental policies or regulations that perhaps look into alleviating the disparities in farmers' affording such technology and equipment. I understand there is a need for farmers themselves being trained and not be reliant and dependent on sources of funding, so it might be sponsorships in kind and in training might be a potential long-term option. That being said, more help is definitely needed in issues like having suitable infrastructure and helping the less advantaged groups of people like the poorer groups and women, so like you've mentioned its crucial that further research and policies take these into account.
ReplyDeleteThank you for your blog post it was really insightful!
I like the exchanges above and think that this blogpost engages very well some of the key papers on this matter. To help answer Stephanie's query about sustainability (not surprisingly for a Californian considering the recent drought and its threat to groundwater-fed irrigation there) UCL-led research in progress reveals that the low-storage aquifers across the inner tropics receive recharge each monsoon so although storage is low, it is likely to be regularly replenished. Further, there is evidence that semi-arid and arid regions receive more recharge - albeit more localised and less frequent than the humid inner tropics - so there is further evidence of the apparent physical sustainability of GWI. However, as you and Chi Hwee Chua have noted, it is often the social and economic factors that determine the success or failure of GWI. What might be the role played by markets?
ReplyDeleteThanks for the insight. To answer your question, firstly, I think the success of GWI depends on access to markets. This can include basic infrastructure such as roads, transportation or Wifi connection. Additonally, the distance to markets is vital and there might have to be a trade-off between proximity to markets and most efficient access to groundwater. It can however, be suggested that also the proximity to large-scale irrigation-based farms may be beneficial, as it allows smallholders to make use of their infrastructure.
DeleteNevertheless, competion on the market and demand for goods also affects rural livelihoods of smallholders. Here, it really depends on the efficiency of the groundwater irrigation system to increase productivity, whether smallholders can compete with large-scale farming products. But, studies have shown that smallholders are often more efficient, as they can make use of unpaid labour (e.g. family) and might therefore be more competitve on the market. However, compared to large-scale farms, they might lack connections to large buyers or global industries. Thus, here again infrastructure plays an essential role.