A2 CAMBRIDGE GEOGRAPHY: HAZARDOUS ENVIRONMENTS - SUSTAINABLE MANAGEMENT IN HAZARDOUS ENVIRONMENTS. It contain the case study about Bioengineering in Malaysia.

1. A2 GEOGRAPHY
HAZARDOUS ENVIRONMENTS
CASE STUDY
BIOENGIENEERING IN MALAYSIA
9.4 SUSTAINABLE
MANAGEMENT IN
HAZARDOUS ENVIRONMENTS

2. LEARNING OBJECTIVES
To acquire in-depth knowledge and understanding of
contrasting hazardous environments.
Multiple focusing on:
• location – use of sketch maps
• the hazard or multiple hazards
• the strategies employed to predict and reduce impact
(manage the hazard)
• the relative success of those strategies
(i.e. positive and negative aspects)

3. CORE
CAMBRIDGE

4. FRASER’S HILL, PAHANG, MALAYSIA
Fraser’s Hill is one of six major highland rainforest areas
that are frequently visited, also known locally as “hill
stations” in Peninsular Malaysia.
Rising 1,200m above sea level on the Titiwangsa Range,
straddling the Pahang-Selangor border, Fraser’s Hill
encompasses pristine highland forests on steep terrain.
It provides important ecological functions including as a
major water catchment area, being the source of two large
river systems: Sungai Pahang and Sungai Selangor.

6. FRASER’S HILL’s BIOLOGICAL DIVERSITY
It has often been taken for granted that Fraser’s Hill and
its surrounding forests will remain intact and continue to
harbour the rich biological diversity.
However, this biological diversity is being threatened by
illegal collection of plants and invertebrates such as
orchids and spiders, pollution, climate change and
unsustainable tourism activities.

8. THE USE OF GEO-MATERIALS FOR EROSION
AND SEDIMENT CONTROL
FRASER’S HILL, PAHANG, MALAYSIA
In Malaysia, research on bioengineering has involved
studies on plant selection for the re-vegetation of cut
slopes along highways.
Bioengineering designs have great potential and
application in Malaysia because in deforested upland sites,
landslides are common, particularly during the wetter
months between November and January.

10. POST-LANDSLIDE RESTORATION
FRASER’S HILL
Fraser’s Hill is an area of lower montane forest and
receives 200–410 mm of rainfall each month.
Post-landslide restoration works involving conventional
civil designs are costly and sometimes not practical at
remote sites.
Because of these constraints and the low risk to lives and
property, bioengineering was the option taken for erosion
control, slope stabilisation and vegetation establishment.

12. INITIAL WORK AT FRASER’S HILL
Two study plots were chosen and one control plot.
Initial work involved soil nailing, using 300 live stakes of
angsana tree branches and 200 cut stems of ubi kayu.
Subsequently, major ground works involved the
installation of geostructures.
Tall saplings of Toona sinensis, a fast growing tree species,
were then planted at the toe of the slope for long-term
stability.

14. LIVE STAKES AND CUT STEMS
At the end of 6 months, the live stakes became living trees.
A high percentage of angsana stakes (93%) sprouted shoots
and roots after a month, and 75% of ubi kayu stems
sprouted leaves within a week.
Vegetation cover on slopes helped reduce soil erosion
because shoots lowered the intensity of raindrops falling on
the exposed soil.
Furthermore, roots functioned like mini soil nails to
increase the shear strength of surface soils.
Thus, live stakes were effective in stabilising unstable
slopes, and their use in bioengineering should be promoted
in the wet tropics.

16. SLOPE STABILITY
Without the erosion control measures, there was aggressive
soil erosion during heavy downpours, which caused
scouring of the steep slope below the tarred road and
resulted in an overhang of the road shoulder.

18. TRAPPED SEDIMENTS AND
VEGETATION ESTABLISHMENT
After one year about 75% of one study site was covered by
vegetation, while 90% of the second plot was revegetated.
There was no more incidence of landslide at these two plots.
However, at the control plot, there was further soil erosion,
which resulted in further undercutting of the slope face.
At the control plot, after 1 year, only seven plant species
were present. These were weeds.
The poor vegetation cover is probably due to unstable soil
conditions caused by frequent soil erosion and minor
landslides.

20. EVALUATION OF GEO-STRUCTURES
The geo-structures were installed at a cost of US$3078,
which was cheaper than restoration works using
conventional civil structures such as rock gabions, which
would cost about US$20,000.
As the site is fairly remote, higher transportation and
labour costs would have contributed to the higher cost of
constructing rock gabions at this site.
On the other hand, the geo-materials, which were
abundantly available locally, were relatively cheap to make
or purchase, and this contributed to the low project cost.

22. GEO-MATERIALS
The geo-structures were non-polluting, required minimal
post-installation maintenance, were visually attractive and
could support greater biodiversity within the restored
habitats.
The geo-materials used in the project, such as coir rolls and
straw wattles, biodegrade after about a year and become
organic fertilisers for the newly established vegetation.
After 18 months, the restored cut slopes were almost
covered by vegetation, and there was no further incident of
landslides.

24. GLOSSARY
Bioengineering is the use of vegetation in engineering, for
example the selection of suitable plant species for the re-
colonisation of areas following landslides.
Geo-materials refer to the use of naturally occurring
materials such as vegetation in engineering.
Geo-structures are structures constructed from geo-
materials such as bamboo bundles (fachines), coir rolls and
straw wattles.

25. TEST
YOURSELF

26. QUESTION
Evaluate the success of one management scheme in a
hazardous environment that you have studied.
5 MINUTES

27. ANSWER – PART 1
The use of geo-materials has been very successful at
Fraser’s Hill, Pahang.
As the site is fairly remote, higher transportation and
labour cost would have contributed to the higher cost of
construction of rock gabions.
In contrast, the geo-materials that are abundantly available
locally are relatively cheap to make or purchase.
The geo-structures were non-polluting, required minimal
post-installation maintenance, were visually attractive and
could support greater biodiversity within the restored
habitats.

28. ANSWER – PART 2
The geo-materials used in the project, such as straw
wattles, biodegrade after about a year and become organic
fertilisers for the newly established vegetation.
After 18 months, the restored cut slopes were almost
covered by vegetation, and there was no further incident of
landslides.
The geo-structures installed on site were cost-effective and
visually attractive.
The restored cut slopes were more stable and supported
higher biological diversity.
Overall, it was a major success.

29. TYPICAL
MISTAKE

30. Some students forget to comment about the control study –
to evaluate the success of a research project there needs to
be a contrast between the experimental and control studies.