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					GROUNDWATER AND CLIMATE CHANGE


    MANAGING THE WATER BUFFER
        MAIN BACKGROUND MATERIAL


• Adaptation Options for Climate Change Impacts
  on Groundwater Resources (World Bank, –
  2009)

• Groundwater and Climate in Africa
  (Hydrological Sciences Journal, volume 54,
  number 4, August 2009) – Richard Taylor,
  Antonis D. Kousis and Callist Tindimugaya

• CPWC: Cooperative Panel/Program on Water
  and Climate (since 2003)

• Managing the Water Buffer (Acacia Water, Meta
  Meta, BGR – 2009)
    CLIMATE CHANGE IMPACTS ON GROUNDWATER




-    Recharge          -   Temperature
                       -   Precipitation
-    Discharge
                       -   Evapotranspiration
-    Storage
                       -   Sea level rise
-    Quality
                       -   Soil moisture
      RECHARGE : CLIMATE CHANGE MESSAGE
Doll and Florke (2005): global scale 2% increase against 4%
increase in rainfall




70 % decrease in the
western part of Southern
Africa and >30 % increase
in the Sahel

Estimates not appropriate to
scale down to country or
basin/watershed level
(IN)DIRECT CLIMATE AND NON-CLIMATE FACTORS

RECHARGE

•Precipitation: main driver: not only the magnitude
 but also intensity, frequency, seasonality

•Temperature and CO2 may affect evapotranspiration
  > portion of rainfall that infiltrates

•Changes in river flow will affect infiltration (and
discharge)

• Land cover and land use <> climate change

• Non climate factors: land use changes, population
growth, poor management
           CLIMATE CHANGE IMPACTS:

Global estimates give regional trends , not
appropriate to scale down to country /basin level.

Climate factors (direct/indirect) and non-climate
factors

Changes in natural climate variability
IMPLICATIONS FOR GRW DEPENDENT SYSTEMS

  Impacts of droughts and floods on

  • Rural and urban water supply

  • Agriculture

  • Ecosystems


  What are climate change impact <> groundwater
   related issues in yr country??
           CLIMATE CHANGE ADAPTATION
Adaptation: management responses for grw. dependent systems
to risks associated with climate variability and climate change

• Managing grw. recharge
                                                Managing groundwater recharge



• Management of grw. storage
• Protection of grw. quality
• Managing demands for grw.
• Managing grw. discharge
                    Protecting
                   groundwater
                      quality




                                                                                  Managing
                                   Managing                                     groundwater
                                 demand for                                        storage
                                 groundwater
                                                                      Managing groundwater
                                                                           discharge




  • Building the adaptive capacity for grw. management
    EXAMPLE : MGT OF RECHARGE AND STORAGE


•    Management Aquifer Recharge: MAR
•    Managing the Water Buffer: 3R



No regret measures
     MAR



building infrastructure
and/or modifying the
landscape to
intentionally enhance
groundwater recharge


Recharge
enhancement provides
additional storage
         Therefore…..Storage!!

There is a need for small scale, low tech, low
         cost, sustainable solutions!
                Some figures

• Surface water storage per capita
   – Ethiopia 43m3
   – South Africa 750m3
   – North America 6150m3

• Village ponds or domestic rainwater storage
  could add 5m3 per person

• Each additional 10mm groundwater recharge
  could add 200m3 per person



                                     12
             Storage = buffering

     3R concept – Recharge, Retention and Reuse
• Local (cisterns) and subsurface storage (active use
  of aquifer) of surface water for both water- and
  food security

• Its not about allocation scarce water but to catch
  and retain water and extend the chain of use and
  reuse as possible within a basin

• Introduce buffer management at scale – basin by
  basin. Not piecemeal/scattered

• Subsurface storage largest potential in terms of m3
                                        13
EXAMPLE : MGT OF RECHARGE AND STORAGE




                             14
15
EXAMPLE : MGT OF RECHARGE AND STORAGE
SAND DAM




    Abstraction well




     Subsurface storage
                 HOW IT WORKS


• Dam drops the flow velocity and results in
  sedimentation and percolation of water

• Increasing the water availability by storing
  water in the riverbed and banks

• Increased availability of water for domestic and
  other uses such as livestock, irrigation and
  regeneration of natural vegetation
              IMPACTS OF SAND DAMS IN KITUI

Vulnerability          Vulnerability indicators           Before dam   After dam
   Categories                                               construc     construc
                                                            -tion           -tion
                  # of cash crops                            1.5          2.8
Agriculture
                  % irrigated crops                           37          68

                  Water collection Domestic (minutes)        140          90
Special aspects
                  Water collection Life Stock (minutes)      110          50

Gender            Average walking distance women to           3            1
                     water (km)

Economic          Income (US$./year)                         230          350

Health            % households suffering from                31.6          0
                     malnutrition
Every Body has the right to be buffered

				
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posted:4/2/2012
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