use of groundwater data in lusaka, zambia alison parker, david nussbaumer, afua owusu, ian sutton

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

a.parker@cranfield.ac.uk

01234 758120