eW/FS/WE/001
The water environment
WATER RESOURCES: Groundwater Impacts
AD2.3
South African groundwater resources are at risk from the following
threats:
Groundwater abstraction and de-watering, such as the:
 depletion or damage to the reserve
 temporary or permanent loss of the use of aquifers through overabstraction or unnecessary de-watering
 loss of surface water base flow or damage to wetlands and riverine
environments which depend on groundwater
 deterioration of groundwater quality
 intrusion of saline or contaminated groundwater into otherwise
uncontaminated aquifers.
Disturbance of aquifers by mining and related activities e.g.
 opencast mining and quarrying
 underground mining
 land drainage
 mine de-watering
Damage to aquifers by waste disposal and related activities:
 mining and industrial residue disposal (waste deposits)
 power generation ash disposal
 irrigation with waste water, evaporation and storage of mining and
industrial effluent and sludges
 land-based disposal of sewage sludge
 domestic waste landfills
 stockpiles of potentially polluting substances
 hazardous waste landfills
 animal wastes and feedlots
 hydrocarbon storage tanks
Diffuse sources, such as:
 urban development
 farming practices
 peri-urban development
 spills and illegal dumping
Rapid urbanisation and increasing density of residential development in
rural environments pose a significant threat to groundwater quality in
terms of:
 pit latrines, septic tanks and soakaways
 leaking and overflowing sewers
 domestic waste
 inappropriate land use around wellheads
PTO
Pollution pressures on groundwater (adapted from Braune 1994)
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ACTIVITY
SOURCE
TYPE
RISK
CONTROL
AGRICULTURE
- irrigation (return flow)
diffuse
low
difficult
- fertilizer application
diffuse
low
difficult
- pesticide usage
diffuse
high
easy
- manure application
diffuse
low
difficult
- extensive stock farming
(Kraals)
diffuse
moderate difficult
- intensive animal feeding units
diffuse
high
difficult
- afforestation
diffuse
low
easy
- groundwater over-abstraction
diffuse
high
easy
- discard dumps
point
high
difficult
- return water dams
point
moderate easy
- ash dumps
point
moderate easy
- slimes disposals
point
high
- stockpiling
point
moderate easy
- dewatering
diffuse
moderate easy
- underground or opencast
mining area
diffuse
high
difficult
- sewage effluent
point
high
easy
- sludge drying beds
point
moderate easy
- landfills and dumps
point
moderate
- storm water
diffuse
moderate easy
- leaking sewers
diffuse
moderate easy
- storage tanks and pipes
diffuse
moderate easy
- informal housing (on-site
sanitation)
diffuse
moderate difficult
MINING
easy
URBAN SECTOR
depends on
age
PTO
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INDUSTRIAL SECTOR
- industrial effluent
point
high
easy
- bulk storage of chemicals, etc.
point
high
easy
- solid waste
point
high
difficult
- abandoned sites
point
moderate
depends on
age
- evaporation dams
point
high
depends on
age
- waste irrigation
point
moderate difficult
- air pollution
diffuse high
easy
- accidents during transport
diffuse high
easy
OTHER ACTIVITIES
- borehole construction and
abandonment
point
moderate easy
Source:
Contact: ewisa@wamsys.co.za URL: www.waterinfo.co.za
Prepared by: eWISA
(http://www.ngo.ngrida.no)
Copyright: All right reserved
Sponsored by: