Ecosystems Need Ecosystems Need Groundwater Too!Groundwater Too!

Christine ColvinChristine ColvinEnvironmentek, CSIR, Environmentek, CSIR,

South AfricaSouth Africa

IAHIAH

Groundwater discharges as…Groundwater discharges as… SpringsSprings SeepsSeeps Baseflow to rivers and wetlands….Baseflow to rivers and wetlands….

Stream

Groundwater also supports..Groundwater also supports..

Submarine springsSubmarine springs Life undergroundLife underground Evapotranspiration from treesEvapotranspiration from trees

During recent years we have During recent years we have learnt more about negative learnt more about negative

Environmental Impacts Environmental Impacts associated with groundwater..associated with groundwater.. Pumping reduces dischargePumping reduces discharge Groundwater Groundwater

pathways for pollutionpathways for pollution

But less is understood about But less is understood about the positive Ecological Role of the positive Ecological Role of

GWGW Groundwater Dependent Ecosystems Groundwater Dependent Ecosystems

(GDEs)(GDEs) Vital characteristicsVital characteristics

Quantity of waterQuantity of water Quality of waterQuality of water Timing of waterTiming of water

Aquifers moderate water supply Aquifers moderate water supply to the environment…to the environment…

Aquifers sustain GDE biodiversity, Aquifers sustain GDE biodiversity, environmental servicesenvironmental services & livelihoods& livelihoods

In times of scarcity people In times of scarcity people and ecosytems compete for and ecosytems compete for direct use of groundwater….direct use of groundwater….

Who can dig Who can dig

deepest & fastest?deepest & fastest?

We need to balance people’s We need to balance people’s

needs for water needs for water

and the and the

environment.environment.

Science can help us to Science can help us to understand understand

the full picturethe full picture

Scientific tools to understand Scientific tools to understand vital links include…vital links include…

Remote sensingRemote sensing IsotopesIsotopes Nutrient and water modellingNutrient and water modelling

rainrain

GWGWflushingflushing

If we understand links we can If we understand links we can predict consequences better..predict consequences better..

Impacts of abstractionsImpacts of abstractions Stakeholder trade-offsStakeholder trade-offs Informed decisionsInformed decisions

Urgent action is required to..Urgent action is required to..

Recognise groundwater dependent Recognise groundwater dependent ecosystemsecosystems

Start understanding linksStart understanding links Monitor ecological healthMonitor ecological health Seek informed decisionsSeek informed decisions Allocate groundwater to the environmentAllocate groundwater to the environment