Groundwater resilience: some definitions

Groundwater provides most of the domestic water supply in rural Africa

In ecological science, the term resilience encompasses two aspects of a system: the ability to resist long term damage, and the time taken to recover from a perturbation (Gunderson, 2000).

Adapting this approach to groundwater resources we have two scenarios:

  • The resilience of groundwater resources to long term (decadal) shifts in climate: dominated by the available groundwater storage — larger groundwater bodies will be much less affected by long term shifts in climate than smaller bodies.
  • The resilience of groundwater resources to short term (inter annual) climate shocks: also dominated by the available groundwater storage, but is also influenced by the long term average (decadal) recharge to the groundwater system which will help the system recover more quickly (Calow et al., 2010).

For many people the more important issue is the resilience of the water supplies dependent on groundwater rather than the actual groundwater resource itself.

A sustainable approach to developing groundwater resources usually involves balancing the long term abstraction with the long term recharge after taking into account the needs of the environment. However, research from the behaviour of water sources during droughts has shown two important issues beyond this simple water balance approach:

  1. improved sources are much more reliable than unimproved sources (Bonsor et al., 2010)
  2. boreholes in higher yielding (more permeable) aquifers are generally much more reliable than in lower yielding aquifers (MacDonald et al., 2009).
Long queues develop within the dry season at a resilient water supply

References

Bonsor, H C, MacDonald, A M, Calow, R C.   2010.  Potential impact of climate change on improved and unimproved water supplies in Africa.   RSC Issues in Environmental Science and Technology, 31: 25–50.

Calow, R C, MacDonald, A M, Nicol, A L, and Robins, N S.  2010.  Ground Water Security and Drought in Africa: Linking Availability, Access and Demand.   Ground Water, 48: 246–256.

Gunderson, L H.  2000.  Ecological resilience — in theory and application.   Ecology, Evolution and Systematics, 31: 425–439.

MacDonald, A M, Calow, R C, MacDonald, D M J, Darling, W G, and Ó Dochartaigh, B É.   2009.  What impact will climate change have on rural water supplies on Africa?   Hydrological Sciences Journal, 54: 690–703.