Use of groundwater data in Lusaka, Zambia
Alison Parker, David Nussbaumer, Afua Owusu, Ian Sutton
Understanding long-term changes in Lusaka’s groundwater levels
Method
Collect long-term data on:– Groundwater levels– Climate– Groundwater abstraction
Analyse using – Sen’s Nonparametric Estimator of Slope– Seasonal Mann Kendall
Data
Data type Location Length of record
Groundwater levels Sheki Sheki 1 borehole 12 years
Climate City AirportKenneth Kaunda Airport
Since 1950
Abstraction Ngwerere 4 years
Borehole commission dates Lusaka Since 1960
Analysis19
60-1
964
1965
-196
9
1970
-197
4
1975
-197
9
1980
-198
4
1985
-198
9
1990
-199
4
1995
-199
9
2000
-200
4
2005
-200
9
2010
-201
4
0
5
10
15
20
25
30
Years
Cum
ulati
ve n
umbe
r of b
oreh
oles
in o
pera
-tio
n
Jan-02 Jul-07 Dec-121265.51266.01266.51267.01267.51268.01268.51269.01269.51270.01270.5
Sheki 1 BH
Time
Grou
ndw
ater
leve
l (m
-am
sl)
Dec-66 Oct-73 Aug-80 Jun-87 May-94 Mar-01 Jan-08 Nov-140
100
200
300
400
500
600
KK Airport Monthly Rainfall
Time
Rain
fall
(mm
)
Groundwater:
Rainfall:
Number of boreholes:
Fallen 1.7m since 2002
Decreasing significantly
Other data
Private users, irrigation, industry, Water Trusts – could be up to 48% of Lusaka’s water (Shaboko-Mbale 2012)
So how and why is Lusaka's groundwater changing?
• Water levels are declining• Both abstraction and climate change may be playing a part…..• ….. but insufficient data to fully support this hypothesis.
Understand data needs of decision makers and how to improve data management
Method
Interviews with– 4 senior engineers from LWSC– 1 chemist from LWSC– All 10 Water Trust managers
Capacity
Lack of capacity to understand hydrogeological information• Only two Water Trust managers have a background in water
management• SGwR helping to address this
Data collection
• Last year none of the then Water Trusts collected water level date– Four started recently– Four plan to
• All monitor chlorine residuals• LWSC periodically monitors
pH, turbidity, nitrates• Little data sharing or feedback
Conclusion
• Capacity building in groundwater needed for all decision makers• Better data management systems required
Alison Parker
01234 758120
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