Post on 19-Jan-2016
POLYTECHNIC IWRM-MASTER
PROGRAM
Ben van der Merwe
Environmental Engineering Services
ENVES
STRUCTURE OF THE PRESENTATION
• Water Demand Management
• Artificial Recharge
• Water Demand Forecasting Methods
WATER DEMAND MANAGEMENT
• End use of water (Polytech Project)• Water losses on private properties
(Whk N$ 6 m/annum)• Non-revenue water (N$ 25m+/annum)• Benchmarking according to IWA • Pressure reduction (Major benefits )• Measuring of reduced water use (Modelling)
ARTIFICIAL RECHARGE
• Some results
• Development of groundwater models
• Security of supply
• Benefit costs
• Water quality (modelling)
1640
1644
1648
1652
1656
1660
1664
1668
Wate
r L
evel (m
am
sl)
15-May 14-Jul 12-Sep 11-Nov 10-Jan 11-Mar 10-May 09-Jul
9/8A (Inj. Bh) 9/6 (1201 m NE) 9/9 (787 m N)
9/11 (626 m SW) 9/12 (1180 m SW)
Water levels afterC-filter backflushing
Injection
1998 1999
Volume injected:290 000 m^3
ARTIFICIAL RECHARGE INJECTION INTO BH 9/8A AT 62 KL/H
1678
1680
1682
1684
1686
Wate
r L
evel (m
am
sl)
07-Aug 21-Aug 04-Sep 18-Sep 02-Oct 16-Oct
Bh 12/2 459 mSouth
Bh 12/4 1133 m
East
Bh 12/1A1348 mS-West
Injection
1999
ARTIFICIAL RECHARGE INJECTION INTO BH 12/3 (216 Kl/H)
GROUNDWATER CONTOURS
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5/6
6/36/5 6/6
6/7
6/8
6/9
6/11A 7/17/3
7/47/4A7/6
9/3
9/89/8B
10/1
10/2
10/310/4
10/610/6A
10/7
10/10
10/11
11/7
12/7
13/1A13/1B
13/1C13/4A
15/ 4A
6/3A
9/6A
13/3
2982B08
9/6B
1020
6/8A
7/4B9/3A
10/6B10/2A
10/12
10/1A 12/2A
12/1A
15/115/2
15/315/3A
15/415/4B
15/5
14/1A14/1
14/4A14/414/4B
14/4C
11/911/9A
11/6A11/6
11/8A11/8
11/411/4A
11/1011/11
11/12A11/12
11/5
11/7A
14/3
14/2
13/5
6/11
10/13
12/11
12/112/2
12/412/5
12/6
12/912/9m
12/10
9/69/7
9/9
9/109/10m9/11
9/12
9/149/15
9/17
9/18
9/19
9/20
9/13
3A/13A/4
3B/1
5/4
4/34/2
9/17A
6/10
4 obs
5/5
3757337574
375753757637577
37578
37579
3758037581
37582
37583
37584
37585
37586
37587
37588
Kruinkamp
38814
38817
38815
38816
3A/5
1710#
12/3
#
9/16
#
9/8A
#
9/5
M2
M3K1
9/19/2
6/2
Dawe
1/98
11/2
11/1AGross Windhoek Spring Fissure
Wasserber Springs
Gathemann Spring
1660
M1
B
A
N
Boreholes#
Topographical divideWater level (mamsl)
Legend
$ Springs
2 0 2 Kilometers
22°4
0'
22°40'
22°3
5'
22°35'
17°00'
17°00'
17°5'
17°5'
17°10'
17°10'
CITY OF WINDHOEKDepartment of Infrastructure, Water and Technical Services WINDHOEK GROUNDWATER LEVEL CONTOURS MARCH 2001
Compiled by: E. Murray & G. Tredoux, CSIR, Stellenbosch, RSA.Date: November 2001
SECURITY OF SUPPLY(SWECO)
0.0
10.0
20.0
30.0
40.0
50.0
60.0
0.00 0.10 0.20 0.30 0.40 0.50
Cumulative Probability
Cum
ulat
ive
Sho
rtfal
l (M
m3 /1
0-ye
ars) baseline
Scenario 1
Scenario 2
Tsumeb
Berg Aukas
Demand Management
ECONOMIC COMPARISON
IRR NPV B/C
• Phase 1 30.6% N$ 18.9m 2.33
• Phase 2 29.1% N$ 41.8m 2.71
• Phase 3 14.7% N$ 30.17 2.52
WATER BANKING
0
5
10
15
20
25
30
An
nu
al P
rod
uct
ion
in M
m3
Irrigation
Reclaimed
Surface water
Boreholes
WATER QUALITY
• High DOC values Von Bach
• High TDS Goreangab
• High Sulphates Goreangab
• High Nitrates Goreangab
DEMAND FORECASTING
• Improve methods (TSA with variables)
• Develop more accurate unit water use norms
• Try to measure small changes in demand
CONCLUSIONS
• Scope for applied research • Lowering of water losses major benefit to
Namibia (N$ 21m+/annum)• Start small scale AR projects in rural areas
with water stress and/or bad water quality• Develop ground water models for critical
supply areas• Address groundwater pollution • Establish norms for unit water use • Develop more advanced forecasting models
“When the well’s dry, we know the worth of water”
Benjamin Franklin