ByThato Seth Setloboko

Climate and Topography of Botswana

Average rainfall of 450 mmTemperatures range from below zero in the

south and can be greater than 40 degreesTopography is relatively flat with low rates of

surface runoff and deep (>250 m) overburdenLow rates of recharge to its groundwater

with about 40 mm in small areas in the Chobe District in the north and over most of the Kalahari region it 18mm or approaches zero

Overview of Botswana’s Water Resources

Rainfall Distribution

Overview of Botswana’s Water Resources

Rainfall Distribution

ZimbabweNamibia

Zambia

South Africa

Namibia

250

300

350

400

450

500550

600650

Source: Bhallotra 1981

Surface Water Drainage PatternsSurface Water Drainage Patterns

Zambezi River

Limpopo River

Okavango River

Molopo River

Okavango Delta

Okwa valley

Source: Botswana Atlas

Major Surface Water Works on the Limpopo

Name of Dam River Name Capacity (Mm3)

Gaborone Ngotwane 141.4

Shashe Shashe 85

Nnywane Nnywane 2.3

Bokaa Metsimotlhaba 18.5

Ntimbale Tati 26.4

Letsibogo Motloutse 100

Planned Surface Water Works on the Limpopo

Name of Dam River Name Capacity (Mm3)

Dikgatlhong Shashe 400

Lotsane Lotsane 40

Thune Thune 90

Available Surface Water Resources

Name of Reservoir River Yield /annum (Mm3)

Existing

Gaborone Notwane 9.4

Nywane Nywane 1.9

Bokaa Metsemotlhaba 4.9

Shashe Shashe 25.3

Letsibogo Motloutse 30.8

Ntimbale Ntshe 2.95

Planned

Dikgatlhong Shashe 62

Lotsane Lotsane 6.5

Mosetse Mosetse 7.92

Thune Thune 4.18

Estimated yield of existing and planned reservoirs

Available and Potential W/Resources-Cont.

SURFACE WATER RESOURCES

Developed Surface Water Resources = 88 680 000 m3/YearPotential New Surface Water Resources /

Undeveloped = 72 680 000 m3/Year Facts

a) No more dam sites availableb) Concentrated along the Eastern Corridorb) Chobe-Zambezi Transfer Scheme, Lesotho Highlands Water Transfer to Botswana

Negotiations with Riparian States /Transboudary

Groundwater Occurrence PatternsInfluenced by geology and Influenced by geology and climateclimate

Limited, both in quantity and Limited, both in quantity and qualityquality

is unevenly distributed over is unevenly distributed over the countrythe country

And considered non-renewableAnd considered non-renewable

Depth to gw: < 40m in the N Depth to gw: < 40m in the N and E to > 100m in the drier and E to > 100m in the drier central and south-western central and south-western parts. parts.

• Department of Water Affairs: • 27 wellfields for major village water

supply• Water Utilities Corporation:

• Dukwi Wellfield for Sowa Town, Nata & Dukwi

• Botswana Power Corporation: • Paje Wellfield for Morupule Colliery

• District Councils (MLG): • Several wellfields for rural village

water supply• Debswana Mining Company:

• For Orapa, Letlhakane, Damtshaa & Jwaneng Mines

• Private Farmers• For livestock-watering and limited

irrigationAt present there are around 25,000 officially-

registered boreholes in Botswana (BNWMP – Review, 2006) Currently this type of setup is under review by

MMEWR

The ultimate goal being that all the wellfields are coordinated by one organisation

Groundwater Exploitation

Available and Potential W/ResourcesGROUNDWATER RESOURCESDeveloped Sustainable Groundwater Resources = 46 306 000 m3/Year (Does not include Wellfields

that are operated by Mines and other Privately owned Boreholes)

Potential New Groundwater Resources / Undeveloped = 5 501 500 m3/Year

Unknowna) Saline Groundwater Resources- not yet quantifiedb) Other Aquifers – e.g Sand rivers, CKGR, Sorilatholo, etc. c) Groundwater Recharge Rates

Research required

NWMPR Water Demand Calculations

Dam Yield per Dam Cumulative YieldExisting surface water ResourcesGaborone 9,400,000 9,400,000 Shashe 25,300,000 34,700,000 Molatedi 7,300,000 42,000,000 letsibogo 30,800,000 72,800,000 Nnywane 1,930,000 74,730,000 Bokaa 4,500,000 79,230,000 Moshopa 2,950,000 82,180,000 Ntimbale 6,500,000 88,680,000 Existing Groundwater Resources 46,306,000 134,986,000 Potential surface water resourcesLotsane 6,500,000 141,486,000 Dikgatlhong 62,000,000 203,486,000 Thune 4,180,000 207,666,000 Potential ground water resources

Botlhapatlou* 2,555,000 210,221,000

Mabule Dolomite Cluster* 1,095,000 211,316,000 Kodibeleng (Coal Bed Methane)* 1,861,500 213,177,500

NWMPR Water Demand Calculations

2010 2011 2012 2013 2014 2015 2016 Comments1 2 3 4 5 6 7

Total Yield 134,986,000 134,986,000 134,986,000 134,986,000 141,486,000 203,486,000 207,666,000 Demand 206,999,790 187,723,164 190,853,885 193,979,920 197,220,964 200,542,124 203,494,978 Household, Commercial and Institutions 100,353,290 103,193,964 106,324,685 109,450,720 112,691,764 116,012,924 118,965,778

Extract from Volume 5/6

Livestock 77,197,500 36,424,200 36,424,200 36,424,200 36,424,200 36,424,200 36,424,200 Extract from Volume 8 pg 125 & Statistics from Agric

Irrigated Farms 1,314,000 19,970,000 19,970,000 19,970,000 19,970,000 19,970,000 19,970,000 Extract from Volume 8 pg 169, 175 & Statistics from Agric

Mining 28,135,000 28,135,000 28,135,000 28,135,000 28,135,000 28,135,000 28,135,000 Extract from Volume 5/6% Demand met 0.65 0.72 0.71 0.70 0.72 1.01 1.02

Water Demand Clusters InvestigationsThis project was formulated to evaluate the Water Demands, Water Resources and to Propose the most Cost Effective Water transfer Schemes to deliver the Water from Source to the Demand Centre. Concluded in 2008.

Water Demand Clusters 17 Clusters

Cluster No.

Cluster Name / Definition

1 Kgalagadi South (Khokohtsa - Werda - Tshabong -

Bokspits )

2 Gaborone (Ramotwsa - Lobatse - Kanye - Mochudi –

Molepolole)

3 Jwaneng – Letlhakeng-Sekoma

4 Mahalapye

5 Serowe – Palapye

6 Tswapong

7 Bobirwa

8 Selibe-Phikwe village and associated villages - not

Bobonong

9 Francistown

10 Masunga

Water Demand Clusters 17 Clusters

Cluster No. Cluster Name / Definition

11 Nata –Gweta-Sowa Town

12 Central East – Since merged with Clusters 8 & 13

13 Boteti -including Orapa and Letlhakane 14 Chobe- (Kasane - and river side villages and

Kavimba)

15 Maun-(Maun, Toteng and Sehitwa and Delta

villages )

16 Ngamiland (North West Ngamiland and Pan

Handle villages)

17 Ghanzi-Mamuno-Kang

Water Demand/Deficit & Surplus - 2035Cluster

Number

Water Demand

(m3/day)

Water Resource

(m3/day)

Surplus/Deficit

(m3/day)

Comment

1 - Kgalagadi

South

2,740 No regional water

resources available

-2,740 Tsabong currently

provided for by a

sort of small

'wellfield' - series of

spread out boreholes

2 - Greater

Gaborone

70,800 – Gabz Only

115,500 - Rest of Cluster

186,300 - in Total

74,400 -111,900 Assumes average

inflow into both

Gaborone and

Bokaa Dam

3 - Jwaneng 34,00 - Jwaneng Mine

5,700 - Rest of Cluster

39,700

65,000 39,000 Assumes large

operational wellfield

developed at

Botlhalotlau

4 - Mahalapye 42,700 40,000 -2,700 Assumes full high

pumping resource

from Masama

expansion

Water Demand/Deficit & Surplus - 2035Cluster

Number

Water Demand

(m3/day)

Water Resource

(m3/day)

Surplus/Deficit

(m3/day)

Comment

5 - Serowe -

Palapye

30,100 12,800 -17,300

6 - Tswapong Not part of study Not part of study

7 - Bobirwa Not part of study Not part of study

8 - Phikwe 40,300 - BCL Mine

4,600 - Rest of Cluster

44,900 - in Total

53,300 8,400 Letsibogo Dam

main resource

9 -

Francistown

46,100 221,700 175,600 Assumes Lower

Shashe Dam

Completed - Dam

on boundary of

Cluster 8 and 9

10 - North East Not part of study Not part of study

Water Demand/Deficit & Surplus - 2035Cluster

Number

Water Demand

(m3/day)

Water Resource

(m3/day)

Surplus/Deficit

(m3/day)

Comment

11-

Nata/Gweta

6,300 32,700 26,400 Assumes Mosetse

Dam and Gweta

developed

12 - Central

East

No Longer a separate

Cluster

No Longer a

separate Cluster

This Cluster was

amalgamated into

Clusters 13 and 8

13 - Orapa 48,200 - Orapa Mine

3,200 - Rest of

Cluster

51,400 - in Total

43,000 -8,400 Assumes

Letlhakane Mine

closed. Flat rate

for Orapa - does

not include Saline

Option

14 - Kasane 2,900 Extensive from

Chobe

Uncertain and not

included in study

Potentially huge

transfer from

Chobe /Zambezi

Water Demand/Deficit & Surplus - 2035Cluster

Number

Water Demand

(m3/day)

Water Resource

(m3/day)

Surplus/Deficit

(m3/day)

Comment

15 - Maun 15,200 22,000 6,800 Assumes new

wellfields Gomoti,

Kunyere all

developed

16 -

Ngamiland

5,900 30,000 24,100 Extensive

Groundwater

available although

not developed at all

17 - Ghanzi -

Kang

5,400 22,900 17,500 Ncojane Basin fully

developed

3 -Dimensional Surplus and Deficit Map of the Clusters

Greater Gaborone

Shashe and Lower Shashe Dams

Cluster 1

Cluster 17

Water SupplyTo address deficits and ensure a sustainable Water Supply:

Conjunctive use of Surface and Groundwater Resources – Eastern Corridor- Availability of dams/reservoirs- Aquifers to recover during wet seasons- Artificial recharge of aquifers with excess runoff- Groundwater should be used as back-up since surface water is lost to evaporation processes

Use Saline Groundwater where possible e.g Debswana

Construct Water Transfer Schemes

Proposed Transfer Schemes

The net effect of the proposed schemes is to supply those clusters presumed to have a water deficit by 2035, namely Clusters 1, 2, 4, 5 and 13, with water from the Clusters in surplus.

RECOMMENDATIONSWater Demands and Deficit Projections are based

on Population growth rates that needs to be monitored as time goes on to see if changes in population and life styles add extra demand to high density population clusters.

There is a need to reduce losses in the reticulation and bulk transfer systems.

Industry should be encouraged to move/locate in areas where water resources are more plentiful.

Large new industrial developments should be encouraged (financially even?) to locate where water resources are not so scarce

International agreements to water sharing, water abstraction should be started as soon as possible.

RECOMMENDATIONSSurface water must be used preferentially to

groundwater wherever possible even if this means higher water costs.

Transfer schemes should be prioritized and carried out in a structured progressive manner so that each new section can link into providing on going water supply

Saline water should be sought as an alternative for process water at all mines

Water supply projects for private and public sector (including parastatals) should be integrated - for example the recent BPC Paje wellfield area project will be supplying water from north of Serowe to Palapye whilst the NSC is going to be providing water from Palapye to Serowe - ie: there will be two pipelines carrying water in opposite directions along the same section of road

THANK YOUKealeboga