Development on Dolomite

1
Development on Dolomite

• Conservation and Environment
• Dr Sue Taylor, Malcolm Roods and Frans Scheepers
• Feb 2005

2
What is the problem?

• Gauteng is a dolomitic province
• A crescent of dolomitic rock extends from the Far
  West Rand, WHS, Centurian around to Springs
• Larger municipalities such as Tshwane, Ekurhuleni
  and Merafong biggest problem
• Caves, karst landscapes and underground
  water/ecosystems have become an issue through the
  WHS project and monitoring requirements
• There have been some recent sinkholes (eg.
  Bapsfontein) near settlements

3
Dolomitic municipalities

• Do they have disaster management strategies, and
  what do these strategies deal with?
• Are the disaster management strategies
  appropriate (eg. Sinkholes, pollution of
  underground water dealt with)?
• Have we reviewed them?

4
Development activities on dolomite

• GDACE policy of densification and conflict
  between golf estates and low densification on
  dolomite areas
• Townships and cemeteries already on dolomite eg.
  Townships near Springs
• EIA/scoping report reviewed recently on cemetery
  development in Krugersdorp area
• How do we (not experts) interpret a
  geohydrological report in a Scoping Report ?

5
Development issues in Gauteng

• Development needs have grown tremendously over
  the last 10 years and Gauteng is running out of
  prime land from a geological perspective
• Government prohibits residential development
  where underground mine works are shallower than
  240 m from the surface,
• Yet dolomitic land, which often reveals openings
  much closer to surface, is developed without much
  objection.

6
Development and the Council for Geosciences (CGS)

• The CGS is required to give recommendations on
  dolomite before townships are established
• Recommendations do not only consider whether
  buildings would be at undue risk, but also
  consider open areas where people will walk
  (presumably where they would drive are considered
  as well?)
• Geohydrological and geotechnical reports are
  currently required for any development planned on
  these types of rock substrata

7
CGS Approach to Development on Dolomite

• Council for Geoscience (CGS) document -
  Approach to Residential Development on Dolomite
  Oct 2004 document
• CGS guidelines for engineering-geological
  characterisation and development of dolomitic
  land and
• National Dept of Housing Generic Specifications
  for Geotechnical Site Investigations for Housing
  Development where Government housing projects
  are being considered.

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Development on Dolomite

• Provincial and local authoritiess, as well as
  National Home Builders Registration Council
  must use the approach set out in CGS Oct 2004
  document

9
Development on dolomite

• The CGS Oct 2004 document states that
• the Developer must obtain a Record of Decision
  from CGS before the scoping report required in
  the EIA process is drafted, and before such
  document is submitted to GDACE
• The CGS ROD is a prerequisite for the issuing of
  the ROD by GDACE.
• A developer that proceeds with the EIA process
  ahead of the CGS process does so at risk.

10
Land risk classes

• Risk classes have been designated by the CGS
• Recommendations on maximum densities for
  residential type are linked to the Risk class
• Development on risk classes 1 and 2 land
  supported by CGS
• When Development is considered on higher risk
  classes, every effort is required to fully
  understand the geological setting and apply
  conservative judgement throughout.
• Each Local Authority affected by dolomite is mean
  to have a functioning Risk Management System.

11
Densification on land risk classes

• The higher the risk class, the less dense the
  development must be
• Eg. Risk class 1 and 2 allowed residential,
  cluster, high rise (40 - 60 units/ha)
• Risk class 3 (a) up to 18 u/ha
• Risk class 3 (b) up to 10 u/ha
• Risk classes 5, 6,7,8 no residential
  development

12
GDACE Development on Dolomite Policy

• Do we need a Development on Dolomite policy?
  CGS approach sufficient?
• Develop GDACE Development Checklist to determine
  whether the CGS survey and ROD was completed?
• What about other dolomite issues?

13
Other items to include in a GDACE Development on
Dolomite Policy

• Recommendations for development near caves and
  bat roosts (and set buffer zones)
• Recommendations for informal settlements (ie.
  Those that have never gone through an EIA process
  or been reviewed by the CGS)?
• Recs for development near known or new sinkholes
  (and set buffer zones) and guidelines for further
  development in these areas

14
Other Problems with Dolomite

• Ground water pollution
• Decrease in surface water infiltration/increased
  runoff
• Over abstraction of ground water for irrigation
• Illegal abstraction of ground water for
  irrigation

15
Other problematic activities on dolomite

• Farming - (GDACE High Potential Agricultural Land
  Atlas) to include impact of dolomite on
  farming/impact of farming on dolomite
• HIV epidemic (increasing the need for) and
  cemeteries on dolomite.
• Sewage works future sewage works if inward
  migration in Gauteng continues. DWAF and CGS
  would play a role here.

16
Other problematic activities on dolomite

• Farming - (GDACE High Potential Agricultural Land
  Atlas) to include impact of dolomite on
  farming/impact of farming on dolomite
• HIV epidemic (increase in need for) and
  cemeteries on dolomite.
• Sewage works future sewage works if inward
  migration in Gauteng continues. DWAF and CGS
  would play a role here.

17
Other key problems

• Mining activities leading to Acid Mine Draining
  (horse has already bolted but how to deal with
  future problems).
• Rehabilitation of AMD polluted areas?
• Boksburg mine dump (reclamation) half of this
  is situated on top of dolomite. How was this
  allowed?

18
Include in Gauteng Dolomite Policy .

• Policy to include GIS mapping of unacceptable
  land-uses in dolomitic areas/buffering
• Same for acceptable land uses (zoning)
• Number of boreholes allowed and water
  abstraction/hour rates (with DWAF)
• Statements about the protection of the various
  dolomitic water eyes (eg. Maloneys Eye in the
  WHS)

19
Policy process

• Policy ineffective
• If not well thought through and role of other
  regulators not understood (DWAF, CSG, DME and
  Local Authorities)
• Need to know contents of disaster management
  policy in Local Authorities that have dolomite
  lands so dont duplicate statements

• Policy effective
• If need is clearly elucidated and appropriate
  guidelines given
• If guidelines are useful in guiding decision
  making
• If fully referenced with stakeholders, role
  players

20
Policy effective if ..

• Policy needs to be mandated as a decision making
  tool in terms of EIA regs
• Needs to be gazetted (stakeholders need chance to
  comment)
• Local Authority buy-in essential

• Buy in from DWAF (or developed with DWAF and CGS)
• Incorporates best practise from international
  examples

21
Conflict with other policies?

• Conflict of mandate and roles between GDACE, DWAF
  and Council for Geosciences

• We should know what the other roles are, and
  perhaps develop a checklist instead to make sure
  everyone has played their part.

22
A Dolomite Conservation and Protection policy?

• Perhaps as well as/ instead of a Development on
  Dolomite policy ..
• A Dolomite Conservation and Protection Policy
  which would include statements, guidelines and
  recommendations about protecting the dolomite
  itself and underground water and ecosystems

• What is the international best practice for
  protecting Gautengs dolomite and karst system,
  underground ecosystems, aquifers, underground
  water dependent ecosystems, biota?
• Deans presentation to look at this further with
  reference to caves.

23
Monitoring of effectiveness of Dolomite policies

• Other provinces with development, dolomite and
  caves (Limpopo, Western Cape, Eastern Cape)
  anything of interest here in terms of monitoring,
  policy or regulations?
• Investigate international methodology for
  monitoring
• Develop indicators, database, carry out
  monitoring
• What monitoring does CGS do?