07900629749863

This article was downloaded by: [The University of Manchester Library]
On: 21 October 2014, At: 01:50
Publisher: Routledge
Informa Ltd Registered in England and Wales Registered Number:
1072954 Registered office: Mortimer House, 37-41 Mortimer Street,
London W1T 3JH, UK
International Journal
of Water Resources
Development
Publication details, including instructions for
authors and subscription information:
http://www.tandfonline.com/loi/cijw20
Groundwater Management
in Drought-prone Areas of
Africa
R. C. Calow , N. S. Robins , A. M. Macdonald ,
D. M. J. Macdonald , B. R. Gibbs , W. R. G.
Orpen , P. Mtembezeka , A. J. Andrews & S. O.
Appiah
Published online: 21 Jul 2010.
To cite this article: R. C. Calow , N. S. Robins , A. M. Macdonald , D. M. J.
Macdonald , B. R. Gibbs , W. R. G. Orpen , P. Mtembezeka , A. J. Andrews & S.
O. Appiah (1997) Groundwater Management in Drought-prone Areas of Africa,
International Journal of Water Resources Development, 13:2, 241-262, DOI:
10.1080/07900629749863
To link to this article: http://dx.doi.org/10.1080/07900629749863
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all
the information (the “Content”) contained in the publications on our
platform. However, Taylor & Francis, our agents, and our licensors
make no representations or warranties whatsoever as to the accuracy,
completeness, or suitability for any purpose of the Content. Any
opinions and views expressed in this publication are the opinions and
views of the authors, and are not the views of or endorsed by Taylor
& Francis. The accuracy of the Content should not be relied upon and
should be independently verified with primary sources of information.
Taylor and Francis shall not be liable for any losses, actions, claims,
proceedings, demands, costs, expenses, damages, and other liabilities
whatsoever or howsoever caused arising directly or indirectly in
connection with, in relation to or arising out of the use of the Content.
Downloaded by [The University of Manchester Library] at 01:50 21 October 2014
This article may be used for research, teaching, and private study
purposes. Any substantial or systematic reproduction, redistribution,
reselling, loan, sub-licensing, systematic supply, or distribution in any
form to anyone is expressly forbidden. Terms & Conditions of access
and use can be found at http://www.tandfonline.com/page/terms-andconditions
W ater R esources D evelopm ent, V ol. 13, N o. 2, p p. 241± 261, 199 7
Downloaded by [The University of Manchester Library] at 01:50 21 October 2014
G roundw a te r M anagem e nt in D rought-prone A rea s of
A frica
R. C . C AL OW 1 , N . S. RO BIN S 1, A. M . M AC D ON A LD 1,
D . M . J. M AC D ON A LD 1, B. R. G IB BS 1 , W . R. G. O RP EN 2,
P. M T EM BE ZEKA 3 , A . J. A N D RE W S 4 & S. O . A PPIAH 5
1
British G eo log ical Surv ey , M a clean Building , Cro w m a rsh G ifford , W allingfor d, O x ford sh ire
O X 1 0 8 B B, U K ; 2 D ep a rtm ent o f W ater A ffairs a nd Fores try, Priv ate Ba g X 3 1 3 , P retoria
0 0 0 1 , So uth A frica; 3 M inistry of Irr ig ation a nd W a ter D ev elop m ent, Priv ate Bag 3 9 0 , C ap ital
4
C ity , Lilong w e 3 , M a law i; Institute of H y drolog y , M a clean Building , C row m arsh G ifford ,
5
W allingfor d, O x ford sh ire O X 1 0 8 BB , U K; G ha na W a ter & Sew erag e C orp o ration , PO Bo x
8 1 0 , T am ale, G h a na
A BSTRACT The issues pertaining to groun dw ater droug ht are review ed w ith particular
regard to the historical and present situations in M alaw i, northern G hana and the
N orthern Province of So uth A frica. These three quite different exam ples highlight som e
of the m ajor dif® culties facing respective governm ents and donor agencies, not least the
shortcom ings of drought-relief drilling program m es,the general lack of routine m onitoring and the need for long er term ana lysis and assessm ent of ground w ater system s than
is currently possible. The distinct character of groun dw ater system s and their reaction
to prevailing and chang ing env ironm ental conditions is discussed, and it is argued that
essentially pred ictable variations in ground w ater drought vulnerability are rarely
planned for or acted up on. M anagem ent issues arising are discussed and it is sug gested
that governm ents, and particularly donors, should place m ore em phasis on long er term ,
pre-droug ht m itigation m easures to reduce the need for costly and som etimes ineffective
em ergency interventions.
Introduction
In the dryland regions of Africa, ground w ater is typically the only perenn ial
source of w ater supply. The im portance of groundw ater has long been recognized by ind igenou s communities, typi® ed by the care commonly afforded to a
village w ell or sprin g. Ind eed proximity to w aterÐ eith er surface w ater or
readily accessible groundw aterÐ has historically been a prim ary determ inant of
settlem ent pattern s.
In more recent years, developmen t of groundw ater resources has increased
rapidly as governmen ts, external support agenc ies (ESAs) and non govern mental organizations (N GO s) have striven to provide dispers ed rural
populations w ith low -cost w ater supplies. A variety of differen t approaches and
technologies have been employed. Many have proved to be uns ustainable in
term s of govern men t upkeep of a grow ing population of w ater points, occasion in g a sh ift in emphasis tow ard s m ore participatory, demand -driven approaches.
0790-0627/97/020241± 21 $7.00
Ó
1997 C arfax Pub lishing L td
Downloaded by [The University of Manchester Library] at 01:50 21 October 2014
242
R. C . C alow et al.
In these efforts, groundw ater has typically been view ed as a reliable and readily
available source of w aterÐ a panacea to meeting rural w ater supply demand s.
W hile m any w ould argue that the emphasis on sustainability is long overd ue,
recen t experien ce of drough t in southern A frica suggests that groun dw ater w ells
and boreholes may fail for reasons other than the com monly iden ti® ed sustainability criteria. One of the prin cipal advantages of groundw ater supply arises
from the bufferin g effect of groundw ater aquifers in relation to climatic variability and w ater dem ands. This buffering capacity is not w ithout its lim its,
how ever; und er certain conditions Ð typically a com bination of rising dry-s eason
demand and red uced rech arge to aquifers from rainfallÐ some w ells and boreholes may dry up altogether and a `ground w ater drough t’ may result. U nd er
such circum stances, absolute w ater shortages m ay quickly supplant crop failure
as the sin gle m ost critical and politically visible issue. Such w as the case in
Zimbabw e w hen, by the end of the 1988± 92 drough t, norm ally reliable w ells and
boreh oles began to dry up, and emerg en cy drilling programmes w ere hastily
in itiated. The effectiven ess of these reactive measures w as in many cases
debatable. Boreh oles w ere poorly sited , com munity participation w as negligib le
and maintenance not prepared for, w ith the result that w ithin a sh ort space
of time, the stock of unsustainable w ater supply sys tems w as sign i® cantly
in creased .
A typical reaction to this observation migh t be that droughts, including
groundw ater droughts, are random and unpred ictable even ts. A key contention
of this paper, how ever, is that som e w ells and boreh oles, and som e areas, are
m uch more vulnerab le to `groundw ater drough t’ than others , and that essentially pred ictable variations are rarely planned for or acted upon. Ground w ater
drough t-managem en t strategies (if they exist) re¯ ect this, and are typically
form ulated in a w ider policy fram ew ork that still treats drough t as a one-off
event, rather than a `normal’ and recurring hazard . Indeed attitudes and
respon ses to drought are typically concern ed not w ith w ater, but w ith food, w ith
the result that other non -food aspects of vulnerab ility have received m uch less
attention. A s Eele (1993, pp. 20± 21) notes:
The evid en ce from comm unities und er press ure sugges ts that the ® rst
consid eration is to protect productive assets, such as breed ing livestock,
tools and land. O ne of the main requirem ents is for people to rem ain
in their villages and often the ® rst problem faced is not access to food,
but rather availability of w ater.
A s this w ater is typically groundw ater, the lack of resea rch into groundw ater
m anagem en t in drought-prone areas is notable. Agains t this background , the
U K’s O vers eas Development Administration (ODA ) has funded a tw o-year
project en titled `Groundw ater management in drough t prone-areas of Africa’,
w ith the objective of identify ing practical measures w hich govern ments, ESA s
and N GOs could support to improve groundw ater managem en t in vulnerable
areas.
G rou ndw ater and D rou ght
W ater Scarcity and the N ature of D roug hts
A t a continen tal scale, A frica is signi® cantly disadvantaged in com parison w ith
Downloaded by [The University of Manchester Library] at 01:50 21 October 2014
G round w ater M ana gem ent in A frica
243
other continents w ith regard to its en dow men t of w ater resources. The ratio of
runoff to precipitation for the w hole of Africa is 0.20, just over half the global
m ean of 0.35, but sign i® cant region al and local variation is apparen t. In M alaw i,
ratios amongst the 38 river catchments vary betw een 0.04 and 0.54; in Zim babw e
ratios am ong 108 catchm en ts vary betw een 0.02 and 0.50.
Tem poral and spatial variability in rainfall also creates situations of unpredictability in many countries , and the continen t has a long history of rainfall
¯ uctuations of varyin g len gth s and intensities. A n obvious expression of this
variability is en demic drough t. Over the last tw o decades, understandin g of the
processes w hich create drought crises has improved signi® cantly, re¯ ected in
better information system s to w arn of the impact of drought, particularly in
relation to food security (Buchanan-Smith & D avies, 1995). N ot surprisin gly,
policy resp onses to drough t have concentrated on food need sÐ most recently on
access and entitlem ents to foodÐ and it has often been dif® cult to m obilize
resources for w ater-sector activities (Chalind er, 1994).
Drough ts m ay result in red uced w ell and borehole yield s and the possib le
dryin g up of groun dw ater sources. H ow ever, the chain of even ts lin king
m eteorological drought to groundw ater drought may be far from clear, and the
spatial and temporal aspects of the relationsh ip rem ain poorly unders tood.
G round w ater R esources and Behaviour
Groundw ater is stored w ithin pore spaces and fractures in rocks. W here the
pores and fractures are interconnected w ater can ¯ ow easily and the rocks are
said to be perm eable. Recharge to groun dw ater usually occurs annually and is
depend en t on a large num ber of factors, including: total annual rainfall; distribution and intensity of rainfall even ts; conn ection to stream s and rivers; soil
type; and land use.
M uch of A frica is underlain by ancient crystalline rocks, typically `basem en t’
granites and gn eisses of ign eous and metamorphic origin. W eathering tend s to
in crease sh allow perm eability creating a mantle commonly 10± 30 m thick of
sands, gravels and fractured rock kn ow n as the regolith . In these areas, the
basement forms a m inor aquifer know n as the basem en t aquifer. A lthough
m inor in hy drogeological term s, such aquifers are of vital importance for
sm all-scale w ater supply, providing w ater for villages and small tow ns in areas
w here there is often no alterna tive source of peren nial w ater (W rig ht & Burg ess ,
1992).
M any factors determ ine the degree of rock w eathering, and aquifer properties
can vary sign i® cantly, even at a local scale. This makes careful sitin g of
boreh oles and w ells important. In gen eral, how ever, reg ional over-exploitation
of ground w ater is a rem ote possibility as abstraction from ind ivid ual w ells and
boreh oles is m odest: m ost rural w ater supply schemes prom ote sim ple techn ologies (boreh oles w ith handpumps; sh allow w ells w ith manual lifting gear), and
the phy sical characteristics of the basem ent aquifer effectively preclude larger
scale developmen t. A s a consequen ce, the am ount of w ater w hich can be
w ithdraw n from such aquifers is m ore a function of the number of access points
to the resource (sources such as sh allow w ells and boreh oles) than its overall
volume. In circumstances w here an adequate rate of abstraction cann ot be
obtained from the w eathered zone alone, fractures in the deeper bedrock m ay be
tapped, albeit at greater expense. O ther areas are underlain by young er sedim en -
Downloaded by [The University of Manchester Library] at 01:50 21 October 2014
244
R. C . C alow et al.
tary deposits and volcanic rocks. Volcanic rocks can have a moderate porosity
and may sustain a range of yield s. W here sed imen tary deposits constitute
sandstones and conglom erates, the potential for ® nding usable ground w ater is
high . C lays and m udstones, how ever, are very poor aquifers and ® nding
groundw ater resources in these rocks can be extrem ely dif® cult. In areas w here
there is ins uf® cient groundw ater to sustain exploitation, for example in basem en t areas w hich have not been suf® ciently w eathered , altern ative (surface)
w ater sy stem s such as surface im poundmen ts and rainw ater harves ting m ay be
important. M ore typically , how ever, m ajor settlem ent in these areas does not
occur, or occurs only w hen deep boreholes tapping fractures in the rock can be
sunk. In the latter case, a conundrum may arise, w hereb y the poorest are those
living in the driest areas w here the cost of w ater provisio n is high est, the need
greatest, but the ability to pay for services is low est.
A further consid eration is w ater quality . O ne of the prin cipal advantages of
groundw ater over surface w ater is its high microbiological quality , aris ing from
its situation below ground and the natural protection this affords. In some areas,
how ever, ground w ater may be brackish and unusable as a source of potable
supply. In others, high natural concentrations of ¯ uorid e, nitrate or arsenic, or
anthropogenic contamination from latrines, may result in health problem s.
The Response of G roun dw ater to D rought
Perh aps the most sig ni® cant aspect of groun dw ater beh aviour in relation to
drough t is the time lag betw een chang es in rech arge and resp onses in ground w ater levels and w ell yield s. This contrasts w ith the relatively `¯ ash y’ behaviour
of surface w ater sources (Figure 1). The res ult is that, w hile som e w ells and
boreh oles may res pond relatively quickly to rainfall variations, problem s in
others m ay take months or even years to em erge, perhaps after several years of
low rainfall. Ind eed , it is quite conceivable that a declin e in w ell/borehole yield ,
or a fall in w ater level, may only m aterialize after the rains have returned and
the meteorological drough t is perceived to be over. This emphasizes the need to
Figure 1. C ontrastin g resp onse and recovery functions of groun dw ater and
surface w ater to drough t. N ote: Groundw ater system s are typically slow er to
resp ond to rainfall even ts than surface w ater system s.
G round w ater M ana gem ent in A frica
245
track the long -term effects of drought through hyd rological and hyd rogeological
sy stem s.
The time lag betw een a m eteorological drought and its im pact on a ground w ater source is likely to depen d on m any differen t factors, including:
·
Downloaded by [The University of Manchester Library] at 01:50 21 October 2014
·
severity and duration of the drought episod e. Longer period s of low or
negligible rech arge are more lik ely to have an im pact on groundw ater
resources and affect w ell and borehole yield s;
design and sitin g of the groun dw ater w ell or borehole. In genera l, w e migh t
expect sh allow , hand-dug w ells to be m ore sen sitive and respon sive to
rech arg e variations than deeper boreh oles, and boreh oles on inter¯ uves to be
more vulnerable than those in valleys;
phys ical characteristics of the aquifer. O f particular importance is aquifer
storage. In basemen t aquifers this is highly variable and depen ds to a larg e
extent on the deg ree of surface w eatherin g and fracturin g w hich has taken
place. H ow ever, it is typically much low er than in more productive, unconsolid ated aquifers;
demands being m ade on the source. Increasing demand may ex acerbate the
effects of rainfall failure. Fluctuations in demand m ay occur over the sh ort
term , re¯ ecting for exam ple the dry ing up of neigh bouring w ells and boreholes, or over a longer period in respon se to factors such as population grow th
and economic change.
·
·
W hile the bufferin g capacity of groun dw ater system s confers obvious advantages in term s of the reliability of supply, it also creates certain problem s. First,
it follow s that groundw ater also recovers more slow ly after drought than surface
sources. The result may be com plex and seem ingly unrelated lin kages betw een
rainfall even ts and their impact on ground w ater resources. Second, it indicates
a need for careful m anagem en t and continuous m onitorin g of groundw ater
supplies. M onitorin g and assess men t programm es w hich beg in and en d w ith
m eteorological and agricultural droughts may fail to detect long er term impacts
on groundw ater, w ith the result that potentially pred ictable and m anageab le
problem s become emerg en cies.
The Fa ilure of G round w ater Sources
The exact cause of the failure of w ells and boreholes is not alw ays clear, sin ce
the lack of w ater coming out of a pump can be due to many different reasons.
Som etim es, it is assumed that an aquifer is bein g overex ploited and groundw ater resources are being region ally depleted . H ow ever, reg ional over-exploitation
is rarely a prob lem in African basem ent aquifers and localized depletion ,
resulting in falling groun dw ater levels in the immediate vicinity of a w ell or
boreh ole, is lik ely to be the prin cipal problem . This is m ost likely to occur w here
the dem ands bein g placed on a w ater source are high, and w here the perm eability of the aquifer is low . In these circumstances, groun dw ater cannot move
suf® ciently quickly to replen ish the w ater abstracted from the borehole or w ell,
and a dew atered zone may form around the source (a cone of depress ion)
restricting the in¯ ow of w ater. Figu re 2 illustrates the distinction betw een source
and resource constraints on abstraction.
Increased stress on a groun dw ater source durin g drough t can also lead to the
failure of the pump. Prolonged pum ping through out the day can put consid er-
Downloaded by [The University of Manchester Library] at 01:50 21 October 2014
246
R. C . C alow et al.
Figure 2. Source vs resource lim itations on groundw ater abstraction. N ote: In both
A and B, ground w ater sources fail. In A, the cause is source-speci® c: boreh ole
abstraction has exceeded boreh ole yield , but red uced pumping w ould en sure the
return of w ater through the aquifer to the boreh ole. In B this is caused by a regional
fall in w ater levels as heavy boreh ole abstraction draw s dow n the regional w ater
table.
able strain on the pump mechanism leading to breakdow ns, especially if w ater
levels are falling and pumping lifts increasin g. The result may be increased
demand on a neigh bourin g source, and thus increased stress (and probability of
failure) on that source. A nd so the cycle continues. The prob lem may be
exacerbated by the cessation of m aintenance programmes as relief drillin g
programmes take priority. The use of poorer quality unprotected sources as
w ater scarcity increases, and the added strain of travellin g long distances for
w ater, m ay have sign i® cant health im pacts on affected househ olds and comm unities. This w as the experienc e of M alaw i durin g and follow in g the severe
drough t of 1991± 92.
A prelim inary conclusion is that the failure of w ells and boreho les durin g
drough t is a function of both increased demand on low -yield ing sources and
G round w ater M ana gem ent in A frica
247
red uced rech arg e to the aquifer. Iden tifying hy drogeological zones that have low
perm eability, w ells and boreh oles that are low yield ing and areas of high
demand migh t therefore help iden tify areas w hich are vulnerable to ground w ater drough t.
Downloaded by [The University of Manchester Library] at 01:50 21 October 2014
The D elicate Balance betw een D em and and Su pply
O ver the course of a year, dem and for groundw ater is likely to reach a peak
w hen w ells and boreh oles are at their most vulnerable, in term s of their yield
and ability to provid e w ater. Tow ards the en d of the dry season, alterna tive
sources of w ater from dam s and rivers m ay disappear, leavin g communities
depend en t on ground w ater. At the same tim e, the number of uses to w hich
w ater is put may increase as families concentrate on brick making and dry
season irrig ation of small veg etable plots. The combined effect is illustrated in
Figure 3 as a dry -season peak in groundw ater demand .
W ater levels in an aquifer are naturally at their low est level at this tim e, w ith
the result that yield s are low . This is illustrated as a dry-season yield trough in
Figure 3 on the w ater availability curve. It follow s that if a w ell or borehole can
only just meet demand for ground w ater in a norm al year, w ater availability and
demand curves may inters ect during a drough t year and dem and may exceed
the supply capacity of the source. A ltern atively, an intersection may only occur
after several years’ poor rainfall, illustrated by the gradual, long -term red uction
Figure 3. C hang es in groun dw ater availability and demand over tim e. N ote:
D urin g a normal dry season, boreh oles may be able to m eet dem and. During a
drough t, w hen dry season dem ands are typically high er and groundw ater
availability low er, boreh oles may dry up. Longer term increases in demand and
red uctions in groundw ater rech arge m ay cause boreho les to dry up in circumstances w here previously they w ould have rem ained viable.
248
R. C . C alow et al.
Downloaded by [The University of Manchester Library] at 01:50 21 October 2014
in groun dw ater availability in Figure 3. The result in either case may be a
red uction in w ater levels, a further declin e in yield , and possibly the drying up
of the source altogether. Failure of the pump m echanism is also m ore likely as
pumping stresses increase.
Figu re 3 also illustrates how long-term increases in demand can make a source
vulnerable to drought that in the past may have provid ed reliable and peren nial
supply. In this ins tance, seasonal and drought-related ¯ uctuations in demand
m ight historically have fallen w ell below the w ater availability curve. A longterm increase in demand , how ever, can eventu ally put the ¯ uctuations above the
curve so that demand w ill exceed supply.
Experience from M alaw i, G hana and Sou th A frica
Three quite differen t countries w ere selected , each w ith its ow n clim atic,
geological, socioeconomic and institutional controls and in¯ uen ces. M alaw i and
South Africa have both experien ced recen t and severe drough t in the 1990s, most
notably in 1991± 92 w hen low rainfall affected the entire southern hem isphere
cropping season. M alaw i has contin ued to suffer, w ith some relief given by the
1995± 96 rains (the effect of the drough t is ongoing due to the cum ulative effect
of successive low rainfall years). South A frica has a low rainfall index and a
variability that exceed s that of the Sahel. H ere, the 1991± 92 drought w as
reported as bein g the w orst since 1982± 83, the latter havin g been the w orst sin ce
the 1920s. Ghana is som ew hat differen t and is not gen erally consid ered as
suffering from recurren t drough t. H ow ever, although humid tow ards the coast,
cond itions become progres sively drier inland and the U pper and N orthern
Region s w ere badly affected by drought betw een 1982 and 1984.
M alaw i
C onsid erable efforts have been made over the last tw o decades to increase w ater
supply coverage in rural areas of M alaw i as a central feature of povertyalleviation and drough t-relief activities. Extern al assistance has supported much
of this w ork, and M alaw i has taken on a mix of multilateral, bilateral and N GO
in put, as w ell as comm itting funds from central govern ment. M uch of this
support has been targeted on speci® c projects in the form of capital assistance
for boreh ole construction and handpump installation. In more recen t years, a
change in approach has been occasioned by the W ater Departmen t’ s inability to
service a grow ing population of w ater supply sources, and efforts are now
under w ay to promote com munity-b ased managemen t and participation. The
importance of ground w ater as a relatively low -cost source of potable supply is
expected to grow , and groundw ater sources already serve the majority of the
rural population. H ow ever, at any one tim e it has been estim ated that som e 25%
of w ells and boreh oles are out of operation, malfunctionin g and/or dry because
of extended drough t (U N ICEF, 1995).
Like many other countries in eastern and southern Africa, Malaw i suffered the
w orst drough t in over 40 years follow ing the failure of the 1991± 92 seasonal
rains. The 1991± 92 rainfall w as only 67% of the long-term average, the second
m ost severe shortfall of the century, w ith the highest sh ortfalls record ed in the
south of the country. C oming on top of a refugee crisis and econom ic and social
G round w ater M ana gem ent in A frica
249
Downloaded by [The University of Manchester Library] at 01:50 21 October 2014
dislocation, the im pact of the drought w as severe, exacerbating an already bleak
social and economic situation.
The im pact of the drough t on the nation’s w ater resources w as profound.
M any rivers and piped w ater system s depend en t on them dried up for extend ed
period s, causing hard ship to tow ns and cities . Perhaps the greatest effects w ere
felt in the many small villages in rural areas, how ever, w here sm allhold ers saw
their crops fail and w here the majority of the population are depend ent on
groundw ater from boreh oles and traditional sources such as sh allow w ells and
river dugouts. H ere, most sh allow w ells w ere reported as dryin g up altogether,
a hith erto unh eard of phen omen on; traditionally shallow w ells have been dug at
the end of the dry season to en sure peren nial supply. The result w as grow ing
reliance on groun dw ater w here it could be accessed through serviceable boreholes, and use of unprotected w ater sources (including Lake M alaw i) not
routinely used for domestic use. W ith relatively lim ited boreh ole coverage at the
time, especially in the most den sely populated and w orst affected south of the
country, and w ith large num bers of boreho les and pumps out of comm iss ion
because of maintenance problem s, villagers (mainly w om en ) w ere forced to
w alk long distances and queue for many hours for w ater. By N ovember 1992,
govern ment reports indicated that some 3 m illion people across the country had
in adequate w ater supplies, a situation exacerbated by the presen ce of over
1 m illion refugees in the south of the country ¯ eeing w ar in M ozambique.
Although the drough t und oubtedly affected the w ater-supply situation in all
areas of the country , national ® gures tend to mask im portant regio nal and
sub-region al variations in impact. The lack of reliable and compreh en sive spatial
and time-series data inhib its evaluation (see below ). In particular, it is dif® cult
to gauge the longer term effects of the 1991± 92 drought on groundw ater
resources and the cumulative effect of successive low -rainfall period s. N everth eles s, som e important patterns and issues do emerge:
·
·
·
·
Rainfall is characteristically variable, and even adjacent villages reported
stark ly contrasting ground w ater drough t experien ces. It seem s likely that
geolog ical variation may contribute m ore to differing regional experien ce.
Relatively few boreh oles appear to have dried up completely; those that did
w ere concen trated in hilly and mountainous areas, on aquifers of lim ited
thickness and storage capacity. H ow ever, the drough t exposed the shortcom ings of the governm en t run maintenance programme, and the fact that so
many w ells and boreholes w ere not functioning before the drough t
sign i® cantly exacerbated its impact w hen it did occur.
Determ in ing the cause of failure of boreh oles is dif® cult, and pum p failure,
siltin g up of the hole, falling ground w ater levels and other problem s m ay all
result in an in ability to pump w ater to the surface. Measurem ents taken from
a compreh en sive netw ork of dedicated monitorin g sites w ould have allow ed
technicians to distin guish betw een resource and source problem s, but such a
system w as not (and is not) in place.
W hile the m ajority of sh allow w ells w ere reported as drying up, some w ells
in areas w ith sh allow w ater tables (e.g. in the vicinity of large dambo system s)
rem ained viable.
The social and economic consequen ces of the ground w ater drough t are dif® cult
to quantify , but indicators of stress included mountin g health problem s, long
queues for w ater and inter-village con¯ icts over w ater supplies. The health
Downloaded by [The University of Manchester Library] at 01:50 21 October 2014
250
R. C . C alow et al.
in formation system in M alaw i routinely collects larg e amounts of data most of
w hich are never analysed , making it dif® cult to compare data across years and
seasons. H ow ever, diarrh oeal and cholera outbreaks occurred durin g the
drough t, and an epidemic of sh igella dysen tery began in the Southern Region in
early 1992, even tually spreading through out the country (SAD C, 1993). Rural
clinics w ere reportedly inundated w ith sick infants. Rates of maln utrition, on the
other hand , w ere relatively low , suggestin g that the principal health problem
m ay have been w ater, rather than food related. D rought conditions persisted
in to the 1992± 93 and 1993± 94 w et seasons; w ith the succession of drought years
having a cumulative, though largely undocumen ted, effect. The result has been
a continuation of w ater resource problem s, lasting w ell beyon d the en d of the
sh orter term food crisis.
Reliable in formation on the status of rural w ater supplies w as unavailable at
the onset of the drough t, and is a continu ing constraint on w ater sector plannin g
and managemen t (UN ICEF, 1995). Instead, the govern ment initiated a series of
emerg en cy w ater supply assess men ts, w ith lim ited support from the donor
community, and set up a W ater Security C omm ittee. At the sam e time, and
follow ing governmen t appeals, a massive capital programme of w ell drillin g and
rehabilitation w as launched , supported almost exclusively by ESAs and conducted by N GO s. The effectiven ess of the em ergenc y drillin g programm es in
reliev ing im mediate w ater stress w as question able. In som e cases, w ells w ere
sunk only after the return of the rains because of logistical and technical
dif® culties , and one em ergenc y programme design ed to addres s groundw ater
problem s in 1992 w as only com pleted in 1995. C oncern s have also been voiced
about the sustainability of such programm es, as the nature of the w ork effectively precludes comm unity involvem ent in the choice, design and sitin g of
w ater points. Follow -up funding for the creation of community support structures has also been dif® cult to obtain for emergen cy projects once the em ergenc y
is perceiv ed to be over.
N orthern G hana
Like M alaw i, Ghana is heavily depend ent on external assis tance in its attempts
to increase rural w ater supply coverage, w ith developmen t efforts project based
and traditionally focused on the provision of infrastructure (`hard w are’ ). Similarly , much of the rural population is depend ent on groundw ater durin g the dry
season, and `top-dow n’ approaches to the provision of serv ices are being
substituted by comm unity-b ased programmes in w hich local people take responsibility for the choice and upkeep of facilities. Ghana is not typically
drough t prone, but has experien ced severe drough t in the past. In addition, larg e
areas of the country have vulnerable, low -yield ing aquifers w hich provide
unreliable supplies.
Durin g the early 1980s there w as a period of red uced rainfall in northern
Ghana, culminating in 1983 w hen rainfall w as only 65% of the yearly average.
In drough t-free years, north ern Ghana has rainfall in excess of 1000 mm/year
w ith a 4± 5-month dry season. During the dry season of 1983, bush ® res raged
throughout Ghana causing gen eral damage and exacerb ating the effect of the
drough t. A s boreh oles began to fail, w omen had to travel much longer distances
for w ater and in some cases had to pay for usin g neigh bourin g w ells . In one
particular village, Yawn, near the Burkin a Faso border, w om en ® rst had to
Downloaded by [The University of Manchester Library] at 01:50 21 October 2014
G round w ater M ana gem ent in A frica
251
Figure 4. Long term hyd rograph for three boreh oles in Upper Region, Ghana. N ote:
In contrast w ith the sh allow er aquifers, w ater levels in the deep aquifer w ere still
fallin g at the en d of the meteorological drough t in 1984.
·
queue for severa l hours to use their ow n w ell and , as the drough t progres sed ,
eventu ally had to buy w ater from a village in Burkin a Faso.
Tw o differen t hyd rogeological reg ions are presen t in north ern Ghana: (a) the
U pper Reg ion w ith moderately yield ing w eathered basem en t; and (b) the
N orthern Region w ith very poor yield ing sh ales and m oderately yield ing
sandstones. Boreh oles and w ells in the N orthern Region that draw on shales are
particularly low yield ing and even in non-drough t years can be unrelia ble. In
gen eral the boreholes and hand-dug w ells w ithin the w eathered basem ent in the
U pper Region are reliab le in norm al years. As a res ult of the relatively high
annual rainfall in northern Ghana there is consid erable reliance upon surface
w aters , both ephemeral stream s and larger dugouts and dam s. The reliance on
surface w ater in non-drought years put consid erable pres sure on groundw ater
sources w hen the surface w ater failed.
Long-term groundw ater-level measurem ents are available at a number of sites
in the Upper Region, but none is complete. In particular, records betw een 1979
and 1984 are missing . The reason for the gap in data is a fam iliar one: the ® rst
phase of an ESA-funded project en ded in 1979 and the second started in 1984.
W hen the funding en ded , so did the monitorin g. Suf® cient information, how ever, is available in the hyd rographs to show some general points about the
respon se of the aquifer in north ern Ghana over the past few years (Figure 4).
Several points em erge:
·
·
·
There appears to be little long-term decline of ground w ater levels. M easurements in 1993 are roughly sim ilar to measurem en ts in 1976.
Seasonal ¯ uctuations appear greater in boreh oles w ith sh allow er w ater tables.
W ater levels in the deeper aquifers w ere still declin ing at the en d of the
meteorological drough t in 1984. The low est w ater levels w ere record ed in late
1986.
Shallow aquifers had already started recoverin g by 1984.
The declin e in w ater levels durin g the drough t w as associated w ith a decrease
in the number of operating boreh oles, w ith less than 70% operating in the Upper
252
R. C . C alow et al.
Region of Ghana by the en d of the 1983 dry season. Several contrib utory factors
have been iden ti® ed, besid es the fall of w ater levels below the pum p intake,
in cluding heavy silting and pump failure (Ward rop 1987a, 1987b).
Downloaded by [The University of Manchester Library] at 01:50 21 October 2014
N orthern Province, South A frica
O ne of the ® rst tasks undertaken by the Govern men t of N ational U nity in South
A frica w as to set targets for the provision of basic rural w ater supply and
sanitation serv ices. The challen ge is a daunting one: it is estim ated that over 12
m illion people (roughly 30% of the population) do not have access to an
adequate w ater supply (Van der M erw e, 1995). M ost of these people live in
poorer rural areas, neglected under previous policies w hich favoured comm ercial agriculture and cities. N ot surprisin gly, chang ing govern men t priorities
have en tailed m ajor institutional upheaval and, lik e M alaw i and Ghana, South
A frica is focusin g on demand driven approaches to the provision of serv ices
w hich em phasize community mobilization and participation. At presen t a variety of different organizations are implem en ting rural w ater supply projects,
in cluding governm en t, en gin eerin g companies , parastatal bodies and N GO s, and
efforts are bein g made to build plann ing capacity at reg ional and local levels.
About 80% of South Africa is underlain by second ary aquifers com prising
w eathered and fractured rocks, gen erally of low perm eability and yield .
Groundw ater resources assessm ent and developmen t has hith erto receiv ed low
priority, re¯ ected in the fact that groun dw ater provides only around 13% of total
supply. Of this, rough ly 80% is used for irriga tion on larg e farm s w hich
gen erally overlie the more productive aquifers. Grow ing com petition for surface
w ater resources, how ever, and the new im perative for meetin g the basic w ater
need s of the country ’s rural population, mean that groun dw ater w ill become an
in creasing ly im portant source of supply. A major dif® culty constraining the use
of groundw ater, how ever, is uncertainty about yield s and demand s, particularly
outsid e the m ain comm ercial areas. The govern men t is currently undertaking a
m ajor mapping and data-collection exercise to overcom e this problem .
In Northern Province, there is a wide disparity betw een the levels of provision
of water supply w ith, in general, areas with the highest population densities
having the low est coverage. These areas correspond to the former homeland areas
of Gazankulu, Lebow a and Vend a, where the proportion of the population w ith
inadeq uate water supplies is estim ated as 95%, 50% and 80% respectively (DBSA,
1991). Groundw ater is the most important source of water supply for the majority
of the population, w ith estim ates ranging between 80% and 90% of total supply.
Ground water is supplied prim arily from boreholes which, for larger settlem ents,
are gen erally motorized and feed into reticulated system s w ith standpipes. H andpumps are found in less densely populated areas and were installed on emergency boreholes drilled during the drough t relief programmes of 1991± 95 (see
below), but are not an important feature of current coverage efforts. Sprin gs are
also an important source of supply. In the central and southern districts of the
province, where population densities are high and perenn ial rivers are few and far
betw een , ground water is often the sole source of supply. Tow ards the w est, large
commercial farm s overlyin g some of the most productive aquifers of the province
abstract large quantities of groun dw ater for irrigation.
South A frica is af¯ icted by severe and prolonged drough ts, often term inated
by severe ¯ ooding . South A frica’ s average rainfall of 500 mm is w ell below the
Downloaded by [The University of Manchester Library] at 01:50 21 October 2014
G round w ater M ana gem ent in A frica
253
·
w orld average, and the timin g and distribution of rains is unrelia ble, particularly
in the summ er rainfall region in the north. Over the last tw o decades, the
country has suffered tw o major drough ts, most recently in 1991± 92. W hile the
effects of the drough t w ere felt countryw ide, the N orthern Province w as
particularly badly hit. In Pietersburg, for example, average rainfall for the
1991± 92 season w as som e 470 mm les s than average, w ith the de® cit increasing
to over 1500 mm in the N ebo area of the former Leb ow a homeland (du Toit,
1996).
In contrast w ith earlier drought relief efforts, w hich focused almost exclusively on cities and the com mercial agricultural sector, attempts w ere m ade to
m itigate the w orst effects of the drough t in the former hom eland areas. A s in
M alaw i, how ever, the lack of reliable and compreh en sive information on the
status of rural w ater supplies and the im pact of drought constrains evaluation.
N everth eless, it is possible to draw som e tentative conclusions:
·
·
·
The drough t exacerbated the already inadequate w ater-supply situation prevailing in rural areas, causin g w idespread w ater stres s. Reports of people
(mainly w om en ) travellin g distances of 10± 15 km to fetch w ater w ere not
uncom mon.
Lack of pre-d rough t m onitoring , communication and coordination problem s
and com munity involvem ent in w ater supply made it very dif® cult to determine the precise cause of w ater-supply dif® culties . H ow ever, reports ind icate
that both surface w ater and ground w ater system s failed , eith er because of
poor operation and maintena nce, or because sources dried up altogether.
Those involved in relief efforts suggest that the prin cipal problem w as one of
pump failure and fuel sh ortages w ith, in particular, the drough t exposing a
backlog of maintenance problem s.
Although absolute w ater scarcity m ay not have been the principal problem , it
seem s clear that there w as a w idesp read red uction in sprin g ¯ ow and
ground w ater levels. Indeed fallin g groundw ater levels and boreh ole yield s
may have contributed to the technical dif® culties noted above. A reas experien cing problem s of absolute groundw ater scarcity included the southern
districts and north -w estern areas of the former Lebow a homeland , w here
ground w ater resources are poor and the success rate for borehole drillin g low .
Longer term dem ographic tren ds may have exacerbated the effects of the
drought, w ith rapid population grow th in rural areas leading to ris ing
demand and increased pres sure on groun dw ater sources. In addition, du Toit
(1996) suggests that the high rainfall of 1974± 76 led to the expansion of
sprin g-side settlem en ts above and beyon d the supply capacity of the sources.
The relief programme w as handicapped by the lack of pre-d rough t information
on rural w ater supplies, and by the urgen cy of action forced upon participants.
A s du Toit (1996) notes, ª The massive mobilis ation of DW AF and other role
players to supply em ergency w ater had all the sig ns of crisis managem ent. The
rush ed ® eld survey s and boreh ole sitin g, despite the good success rate, resulted
in the drillin g of many uns uccessful or unnecessary boreh oles. This contributed
to the perception of unreliab ility of ground w ater amongst the en gineering
profession in South Africa.º H azelton et al. (1994) support this conclusion , notin g
that ª For the rural subsisten ce inhabitants there have been no formal structures
to monitor drought and to provide relief . Often the structures have been set up
Downloaded by [The University of Manchester Library] at 01:50 21 October 2014
254
R. C . C alow et al.
on an ad hoc basis , often w hen drought has reached disaster proportions.º The
programme proved extrem ely costly in term s of both equipm en t and manpow er,
and necessitated the diversion of ® nancial and human resources aw ay from
longer term programmes. D u Toit (1996) estimates that the overall program me
cost DW AF alone in excess of U S$20 million , w ith large sum s of money also
spent by ESAs and N GOs.
The govern ment is now urgen tly addressin g some of the problem s high lig hted
above. In particular, the collection of baseline information on rural w ater
supplies and the communities they serve is seen as a particular priority. Speci® c
data need s iden ti® ed include the names and locations of rural villages, dem ographic features, w ater-supply coverage levels by technology type, and basic
hyd rogeological data, including information on w ater quality . A com prehensive
database of boreh ole information, including at least the location, yield and depth
of boreholes, already exists for other areas, and this has been used to produce
`safe abstraction maps’ delin eating areas lim ited by yield or storage. It is
anticipated that, once baselin e information has been assem bled for the poorer
rural areas, sim ilar manipulative processes can be applied to the data. This may
go a long w ay tow ard s reg ional drough t sen sitivity analysis.
G rou ndw ater M anagem ent Issues A rising
A num ber of im portant issues and conclusion s emerg e from the foregoin g, and
it is possible to suggest a num ber of w ays in w hich ground w ater managemen t
in drought-prone areas could be im proved. H ere, a distin ction is made betw een,
(a) issues and strategies relating to the longer term m anagem en t of groundw ater
resources in pre-d rough t period s, and (b) those relating to short-term , reactive
m anagem en t durin g drought, particularly the role and use of em ergen cy drillin g
programmes.
(a) Pre-drought Proactive M ana gem ent
In all three countries, groundw ater developm en t is continuing apace in an effort
to m eet the grow ing need for safe, low -cost w ater supply. M uch of this
development proceed s in an uncoordinated mann er, driven by the need s of
development projects supported by a w ide variety of organizations. In these
efforts, groun dw ater is typically treated as an ill-d e® ned `black box’ , w ith little
attem pt made to tailor policies and technologies to res ource characteristics.
Typically, res ource assessm ents are project speci® c; m onitoring programm es, if
undertaken at all, beg in and en d w ith projects; and drough t is rarely plann ed for
despite its routine occurren ce. As a result, no compreh en sive picture emerges of
eith er the national status of rural w ater supplies or the status of the groundw ater
resources themselves , and pred ictable variations in groundw ater drought vulnerability are not accounted for. An a priori conclusion is that, w ithout such
know led ge and the policies w hich re¯ ect it, groundw ater drough ts w ill contin ue
to take govern men ts, N GOs and donors by surprise, larg e sum s of money w ill
be spen t on em ergenc y drillin g program mes, and w ater supply infrastructureÐ
irresp ective of w hether it is `managed’ by govern ment or local peopleÐ w ill be
subject to pred ictable failures.
G round w ater M ana gem ent in A frica
255
G round w ater M onitoring and A ssessm ent
Downloaded by [The University of Manchester Library] at 01:50 21 October 2014
Issues. The need for a clear unders tanding of the resource base is ess en tial if
development of groundw ater is to proceed in an appropriate and sustainable
fashion . Similarly , the need for reliab le and timely information on the status of
rural w ater supplies w ould seem fundam en tal to any form of groundw ater
drough t plann ing and mitig ation. The lack of this inform ation, at least in an
accessible and usable form , has been a seriou s constraint on sector plannin g and
m anagem en t in Ghana, M alaw i and South Africa. In all three countries, the
situation is exacerbated by the fact that data holdings w hich do ex ist are
dispersed am ongst a range of differen t organizations (govern men t, N GOs,
consultants) at different levels (national, regional, local). A typical result is that
new projects are designed w ithout the ben e® t of existing data, the activities
of differen t organizations are in suf® ciently coordinated, and groundw ater
development proceed s in an ad hoc mann er.
In M alaw i, U N ICEF (1995) note that up to date com pilation of data has been
constrained by lack of institutional stability and capacity, and the need to
respon d to drough t and refugee emerg en cies. In addition, funding constraints
and lack of transport are a continuing constraint to data collection at ® eld level;
it is not uncommon for district-level techn icians to be w ithout transport for
m onths, makin g com pilation of regu lar w ater-supply assessm ents impossible.
The govern men t recognizes the need to instigate a com prehensive w ater-lev el
and w ater-quality m onitorin g and databasing scheme, and to organize existin g
data (w ell and boreh ole records) in electronic form, but attracting donor support
for these activities is dif® cult. Similar issues arise in Ghana, w here data holdin gs
are reg ional rather than national and w here m any N GOs hold their ow n
databases . In South Africa, efforts are bein g made to develop a N ational W ater
Supply and Sanitation M anagem ent Inform ation Sys tem to add ress the problem .
·
·
·
Strategies. These are numerous, but there is an urgent need to:
recognize the im portance of establish ing (and maintainin g) a sound hyd rometeorological and groundw ater database that can be used routinely in the
plann ing of new projects and in groundw ater drought mitig ation. Govern ments, ESAs and N GOs typically place a low priority on these activities.
Reasons include: dif® culties in quantifying bene® ts and veri® able indicators of
success, especially over the shorter funding period s now being demanded by
donors; a preference for dealing w ith im mediately tangible problem s w hich
produce sh ort-term res ults (e.g. borehole drillin g program mes and the installation of handpum ps); and reluctance on the part of hard -pressed govern ments to divert res ources aw ay from m ore pressin g, operational issues;
establish monitorin g sys tems w hich extend beyon d rainfall, surface w ater and
food security ind icators to ground w ater and ground w ater supply status,
recognizing that anteced ent conditions (e.g. river ¯ ow s and groundw ater
levels of the previous year) are essential guides for pred icting future hyd rogeological (not meteorological) conditions. Ideally, these sh ould be able to
distinguish betw een the differen t factors contributing to w ell/boreh ole failure,
in particular, the distin ction betw een source and resource stress es and source/
resource and maintena nce problem s. This indicates a need to collect data on
ground w ater conditions from a dedicated netw ork of m onitoring points;
en sure that the role of monitorin g and assess men t is clearly de® ned w ithin the
256
R. C . C alow et al.
new in stitutional arrangem en ts em ergin g in the reg ion. In Ghana and M alaw i,
for example, many of the operational tasks traditionally carried out by
governm en t are being turned over to local comm unities. A sim ilar approach
is being advocated in South A frica. In theory, this sh ould allow w ater
departm en ts to devote m ore tim e and res ources to matters such as monitorin g
and asses smen t, but task s and fund ing arrangem en ts have yet to be clearly
de® ned .
Downloaded by [The University of Manchester Library] at 01:50 21 October 2014
G round w ater D rought V ulnerability A na lysis and Early W arning Sy stem s
Issues. Some areas are much m ore vulnerable to ground w ater drough t than
others. Key determ inants of vulnerability include features such as aquifer type,
depth of the w eathered zone, w ell and boreh ole yield s and rainfall (amount and
variability). By them selv es, how ever, these factors do not determ ine vulnerability to the advers e im pacts of groundw ater drough t, and some communities
w ill be more vulnerab le to groundw ater drough ts than others. For example, in
areas w here w ater supply coverage is low and population den sity is high , and
in areas heavily depend ent on traditional sources, the im pact of groundw ater
drough t migh t be expected to be m ore severe.
In view of the pred ictable nature of groundw ater drought vulnerab ility (to
in ciden ce and im pacts), vulnerability maps incorporating a variety of differen t
in dices, or `layers’ (see Figu re 5), m ight provid e a useful managem en t tool.
These could be used to help target scarce resources to sensitive areas in
Figure 5. C onceptual framew ork for groundw ater drough t vulnerability m apping.
N ote: H uman vulnerability to ground w ater drough t is determ ined by factors such
as population density and w ell/boreh ole coverage. Phy sical vulnerability is
determ ined by aquifer characteristics and rech arge. Together, human and physical
factors determ ine vulnerability to ground w ater drough t and its im pacts.
G round w ater M ana gem ent in A frica
257
Downloaded by [The University of Manchester Library] at 01:50 21 October 2014
pre-drough t periods , and ensu re that appropriate technical choices in term s of
drilling methods and the choice and design of w ells and boreh oles are m ade in
differen t areas. In the grow in g number of instances w here comm unities them selves make their ow n choices from a men u of different w ater supply options
(e.g. in G hana), the menu offered could be tailored to en sure that the options on
offer are appropriate to local hyd rogeological conditions . In addition, such m aps
m ight provid e a useful focus for coordin ating the efforts of the differen t
organizations und ertaking w ater supply projects, prompting discussion and
exchange of data and ideas on w ater-supply priorities.
In term s of ground w ater drought pred iction in space and tim e, there is a need
to develop national drough t plans for the w ater sector to include sim ple early
w arn ing system s to w arn of groundw ater problem s and adverse impacts. H ere,
developments are very much tied to progress m ade in establish ing long -term
m onitorin g and assessm en t programm es; reliab le early w arn ing system s depen d
on reliable data and long -term tracking of meteorological and hyd rogeological
trend s. In South Africa, H azelton et al. (1994) suggest that a key elem ent of any
drough t plan sh ould be the establish ment of a W ater Inventory O utlook C omm ittee, w hose principal aim s w ould be to (a) compile and analyse data from
observational netw orks operated by governm en t and N GO s, enh ancing those
netw orks w here neces sary ; (b) determ ine user need s in term s of speci® c data
requirem en ts, format and presen tation; (c) develop trigg ers and an early w arnin g sys tem, usin g a com bination of indices to initiate speci® c and timely actions
by differen t organizations ; and (d) identify drough t-affected areas for targetin g.
An early w arnin g system designed to w arn of groundw ater drough t w ould
need to monitor anteced en t meteorological and hy drological conditions as w ell
as ground w ater indicators (e.g. w ater levels and yield s). Thresh olds w ould also
need to be established such that once exceeded, actions de® ned in the drough t
plan are trigger ed. Indicators of w ater stress could also be incorporated, for
example incidence of w ater-related diseases from clinics. In this w ay, the sys tem
could be stren gth en ed through incorporation of data gen erated by other departm en ts and by other (non-w ater) projects. Experien ce from other countries in the
region (e.g. Zim babw e) indicates that resp onses need to be ¯ exible and not
centrally prescribed; problem s may be high ly localized, and it is only at low er
levels (the low est level at w hich capacity ex ists) that problem s can be assessed
in the proper context and solutions recom men ded.
As a caveat, it sh ould be noted that information by itself w ill not guarantee an
early res ponse. Experien ce w ith early w arn ing system s establish ed to m onitor
food security ind icate how the resp onse can be too little and too late, despite the
existence of a w ell-establish ed w arnin g system (Buchanan-Smith & Davies,
1995). Reasons include the politicized nature of the information gen erated, and
failure to lin k early w arning to resp onse sy stem s.
·
Strategies:
Groundw ater drough t vulnerability m apping usin g various ind ices and manipulative processes is a potentially useful groundw ater m anagem en t tool. In
South Africa the curren t hyd rogeological mapping exercise, w hen coupled
w ith climatic, demographic and other baselin e data, w ill go a long w ay
tow ard s regional drough t vulnerability analysis. It is anticipated that sim ilar
system s can be developed for G hana and M alaw i at relatively low cost, usin g
258
R. C . C alow et al.
Downloaded by [The University of Manchester Library] at 01:50 21 October 2014
·
data alread y held by differen t organizations. Vulnerab ility m aps can potentially incorporate many different layers of information, re¯ ecting the fact that
a combin ation of factors (physical, demographic, socioeconom ic) conspire to
create problem areas. Useful additions, for example, could include dem ographic and w ell/boreh ole coverage data, so that areas w here the impacts of
ground w ater drought m ay be most severe can be iden ti® ed.
Although early w arnin g system s m onitorin g food security are now commonplace, there is a need to develop drought plans w hich incorporate w ater
resources assessm ents , including ground w ater. A n early w arnin g system for
ground w ater drough t could be based around a com bination of ind ices ind icating both occurrence and impact of groundw ater drought, and lin ked to a
resp onse sys tem in such a w ay that, once key thresh olds are exceed ed,
mitig ating actions are trigg ered .
Building in D roug ht R esistance to W ater Su pply Program m es
Issues. M uch can be done in pre-d rough t period s to improve the reliability of
sources durin g droughts . Follow ing on from the above, it is clear that sound
in formation on the w ater resources base and identi® cation of vulnerable areas
can facilitate tailoring of w ater supply developm en ts to local conditions . Ultim ately, decision s need to be made on a pragmatic basis , re¯ ecting both the
w ish es (and increasingly, ability to pay) of local people as w ell as sound
hyd rogeological asses sment.
Greater coordination and sh arin g of information betw een differen t players in
the w ater sector is also req uired , especially as the num ber of N GO s w ith
differin g and multiple accountabilities increases (Edw ard s & H ulm e, 1995). Past
m istakes need to be avoided, and success storiesÐ for example w here the
drough t-proo® ng of rural com munities has been effectiveÐ need to be sh ared. In
addition, the experien ce of all three countries underlines the im portance of
effective maintena nce arran gem ents; the impact of a ground w ater drough t is
potentially m uch w orse if a large proportion of w ater points are alread y
non-operational.
·
·
·
·
Strategies. A number of relatively sim ple measures could be im plemen ted to
prev en t or red uce the likelih ood of ground w ater drough t occurrin g. Exam ples
in clude:
the N orthern Regio n of Ghana, w here shallow w ells are completed to a depth
of not less than 3 m below the natural w ater table, and w here an extra concrete
rin g is cast and left at the w ell head to facilitate deep ening at some time in the
future should the need arise;
w ell/boreh ole deepenin g in selected areas as a routine component of reh abilitation programm es;
the routine sin king of an extra w ell or borehole in villages w here, because of
the nature of the aquifer, falling w ater levels are speci® c to ind ivid ual sources;
the sink ing of deep boreh oles in the m ost favourable hy drogeological locations w hich could be uncapped and used in emerg en cy situations. Such
boreh oles could be used by household s from differen t villages should local
village sources dry up.
G round w ater M ana gem ent in A frica
259
(b) Back-up Em ergency Sy stem s
A key contention of this paper is that greater em phasis on 1, 2 and 3 above is
likely to red uce the need for reactive and costly emerg en cy program mes.
H ow ever, back-up system s need to be in place to tackle em ergenc ies that do
arise. The aim of these sh ould be to relieve w ater stress in drought-affected
communities as quickly as possib le.
Downloaded by [The University of Manchester Library] at 01:50 21 October 2014
Types of Intervention
Issues. A broad range of interven tions is possible w hen resp onding to ground w ater drought. In M alaw i em ergenc y drillin g programmes w ere organized in
respon se to the 1991± 92 drought, and efforts w ere m ade to speed up reh abilitation and maintena nce programmes. In South A frica, emerg en cy drilling program mes have been supplem en ted by w ater-tankerin g operations in the w orst
affected areas of N orthern Province. In both countries (and elsew here), the
effectiven ess of em ergenc y drilling programm es in relievin g w ater stress has
been question ed. In M alaw i, for example, som e drilling programmes did not get
under w ay until after the return of the rains, but hasty organization left little
scope for com munity m obilization and follow -up w ork to en sure sustainability.
In N orthern Provin ce, South Africa, many uns uccessful or unnecessary boreholes w ere drilled , and it is likely that many of those that did produce w ater
m ay now have fallen into disrepair, or have been abandoned . N everth eless, such
programmes rem ain attractive to donors. O ne of the principal reasons for this
is that ® nancial support continues to be much more easily mobilized for
emerg en cies than for long er term efforts aimed at drough t-proo® ng rural comm unities, or indeed for supportin g much need ed monitorin g and assessm ent
programmes.
·
·
·
Strategies:
The lim ited effectiven ess of em ergency drillin g programm es need s to be
recognized by the donor com munity, and greater emphasis need s to be placed
on longer term pre-d rough t prev en tion and mitigation measures.
The use of temporary, stop-gap m easures may be m ore effective than `quick® x’ solutions aimed at rapid in stallation of perm anent w ater supply infrastructure. Such measures include assis ting comm unities w ith the transport of w ater
(e.g. through provision of w ater carts and the animals to pull them ) and,
w here institutional capacity perm its, the tankerin g of w ater by lorry- or
tractor-draw n w ater-bow sers. In Lesoth o, butyl rubber w ater bags (bladder
tanks ) w ere used as reserv oirs, facilitatin g rapid turnaround of tank ers.
Ultim ately, decision s regard ing the appropriateness of interventions need to
be m ade at local level w here prob lem s can be asses sed in context. W ater stress
tends to be a much m ore localized problem than food in security as food can
be transported further and m ore easily than w ater. The challeng e is how to
identify affected communities. H ow ever, this inform ation is rarely available at
national level, and there is a clear need to decen tralize the respon se to
ground w ater drought w ithin the context of a national strategy.
260
R. C . C alow et al.
Downloaded by [The University of Manchester Library] at 01:50 21 October 2014
C onclusions
·
Surprisin gly little attention has been paid to the subject of ground w ater m anagem en t in drough t-prone areas despite recen t experienc e of groundw ater drough t
in Africa. The reasons are many , and include a preoccupation w ith food rather
than hyd rogeological aspects of drought, and m onitoring programmes w hich ,
if functioning at all, focus on im mediate cause-and-effect relation sh ips rather
than longer term tracking of the anteced ent hyd rological and hyd rogeological
cond itions that can lead to groun dw ater drough t.
Groundw ater m anagem en t and drough t experien ces from Ghana, M alaw i and
South A frica are in many w ays unique, re¯ ecting country -speci® c res ource and
rainfall characteris tics and different groundw ater developm en t approaches. Several iss ues transcend individ ual country experien ces, how ever, and point to
w ays in w hich managem ent m ight be improved through out Africa. In particular:
·
·
·
·
There is a need to recogn ize that the processes contrib uting to groundw ater
drought occur over the long er term , and there m ay be great variability in the
tim ing, nature (quantity and quality ) and magn itude of impacts. These processes and variations are potentially pred ictable but rarely accounted for in
w ater sector planning .
A prereq uisite for more effective management of groun dw ater resources and
drought pred iction is reliable, comprehen sive and timely information on the
status of rural w ater supplies. H ow ever, low priority is given to monitorin g
and asses sment activities by governm en ts and donors. W ater departm en ts are
typically concerned w ith m ore pres sin g operational issues, and ESAs seem
reluctant to support long-term programmes w hich do not produce short-term ,
tangible results.
Res earch is need ed to determ ine how cost-effective yet reliab le monitorin g
netw orks can be establish ed and maintained. In addition, m onitorin g resp onsibilities for both data collection and data analysis need to be clearly de® ned
as institutional structures and resp onsib ilities change.
Pre-drought m itigation strategies w hich help to `drought-proof’ rural communities and target resources to vulnerable areas may be m uch more effective
than reactive, `quick-® x’ interven tions undertaken durin g (or often after)
droughts. Em ergenc y drillin g programm es prove popular w ith ESAs, but
evidence from M alaw i, South A frica and elsew here ind icates that they may
sometim es do little to relieve w ater stress and m ay put in place an unsustainable infrastructure.
Over the last decade numerous early w arn ing sy stem s have been set up to
monitor food security , particularly in relation to drough t. There is now a
pressing need to develop sy stem s w hich help to pred ict groundw ater
droughts, detect early sym ptom s of w ater stress and trig ger appropriate
resp onses.
A cknow ledge m ents
The w ork described in this paper forms part of a resea rch and developm en t
contract (number R6233) and a technical cooperation project, both fund ed by the
Britis h O vers eas D evelopm en t Administra tion. The project has been supported
by the M alaw i M inistry of Irriga tion and W ater D evelopm en t, the Ghana W ater
& Sew erage C orporation and the South A frican D epartm en t of W ater Affairs
G round w ater M ana gem ent in A frica
261
and Fores try . The paper is publish ed by perm ission of the D irector, British
Geological Survey (N ERC ).
Downloaded by [The University of Manchester Library] at 01:50 21 October 2014
R eferences
B uch anan -S m ith, M . & D avies, S. (1995) F am ine E arly W arning an d R espo n seÐ Th e M issing L ink.
(L on d on , Interm ed iate T ech nolog y Pu b lications).
C h alind er, A . (1994) W ater a n d Sa n ita tion in E m ergencies: G o od P ractice R ev iew 1 . R elief a n d R eh abilitatio n N etw ork (L ond on , O verseas D evelopm en t In stitute).
d u T oit, W .H . (1996) Ev a luation an d L esso ns Learned from the E m erg ency R ural W ater S up p ly Pr og ram m e
d u ring th e 1 99 2/95 D rou g ht in So u th A frica (Pr etoria, D epartmen t of W ater A ffa irs and Forestry).
E d w ard s, M . & H ulm e, D . (1995) N o n-g ov ernm ental O rga n isation sÐ P erform an ce a n d A ccou n ta bility,
B eyo n d th e M ag ic B ullet (Lon don , E arthscan Pub lications).
E ele, G. (1993) Respon se to drough t: the m icro-econ om ic aspects, paper presen ted at the W orkshop
on M itigating Drough t in D eveloping Cou n tries: T he C on tribution of U K In stitutions, U K D rough t
M itigation W orking Group.
D evelopm en t B ank of South A frica (D B SA ) (1991) W a te r an d S a nita tio n 2 0 00 (Joh ann esburg, D evelopm en t B ank of South A frica).
H azelton, D .G., Pea rson , I. & K ariuki, (1994) D ev elop m ent o f D ro ug ht R espo n se Po licy O ption s fo r th e
C o st E ffectiv e P rovision o f W a ter Sup ply to R u ral C o m m unitie s S ubject to Recu rring D roug h ts (Pretoria,
W ater Research C om m ission).
Southern A frican D evelopm ent C om m un ity (SA D C ) (1993) C o untr y A ssessm ent P ap erÐ M a la w i:
A ssessm ent of th e Ef® ciency o f the N a tio n al R esp on se to the 1 99 2 D roug h t in th e C on te xt o f L o ng -ter m
D ev elop m ent O bjectiv es, Proceed ings of the SA D C Region al M anagem en t W orksh op, Septem b er.
U N IC EF (1995) R ural W ater Sup ply an d Sa n ita tion in M alaw i: S u staina bility throu g h C o m m unity B ased
M an ag em ent (L ilongw e, U N IC E F).
V an d er M erw e, S.W . (1995) A n overview of w ater supply m an agem en t in South A fr ica, A qua , 44(4),
pp. 151± 160.
W ardrop & A ssociates L td (1987a) E va luatio n of B o reho le P erform a n ce P roblem s in the U pp er R eg io n s,
Field Pa per N o. 11, Gh ana W ater U tilisation Pr oject, C IDA Pr oject N o 400/10971.
W ardrop & A ssociates L td (1987b) F inal Rep ort, V ol 1 : G h a na Ð U p per Region , M ain ten an ce /S ta biliza tio n
P roject, C ID A Pr oject N o 400/10977.
W righ t, E .P. & B urgess, W .G. (1992) Th e H y d rogeolog yof Crysta lline B asem ent A frica, Geolog ical Society
Special Pu b lication N o. 66 (L on d on , Geolog ical Society).
Downloaded by [The University of Manchester Library] at 01:50 21 October 2014