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SECTION
3 NATURAL RESOURCES CAPITAL STOCK
| 3.4 |
Freshwater
Resources |
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Water
Supply from Hong Kong
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| 3.4.1.8 |
In
addition to the water supplied from Guangdong
Province, Hong Kong derives 20-30% of its
freshwater from local catchments and reservoirs.
Groundwaters are not heavily exploited for
water supply in Hong Kong though some remote
villages in the New Territories and islands
still depend on wells for irrigation and
domestic consumption (491 households were
supplied by 6 wells in 1995).
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| 3.4.1.9 |
WSD
water gathering grounds, which are comprised
of catchment areas, catchwater drainage
systems and reservoirs, cover approximately
one third of the land area of Hong Kong.
The catchwater drainage systems, in total,
extend for approximately 120 kilometres
and drain into WSD's 17 impounding reservoirs.
Of these seventeen reservoirs, seven are
located on Hong Kong Island, nine in Kowloon
and the New Territories, and one on the
outlying island of Lantau (Table 3.4c).
The combined storage capacity for these
reservoirs is approximately 586 Mm3 of water.
| Table
3.4c Storage Capacity of Hong Kong's
Reservoirs |
| Reservoir |
First
Year of Supply |
Storage
Capacity (Mm3) |
| Hong
Kong Island |
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| Tai
Tam Upper |
1889 |
1.490 |
| Tai
Tam Bywash |
1904 |
0.080 |
| Tai
Tam Intermediate |
1907 |
0.686 |
| Tai
Tam Tuk |
1917 |
6.047 |
| Aberdeen
Upper |
1931 |
0.773 |
| Aberdeen
Lower |
1931 |
0.486 |
| Pok
Fu Lam |
1877 |
0.231 |
| Kowloon
and New Territories |
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| Tai
Lam Chung |
1957 |
20.490 |
| Jubilee
(Shing Mun) |
1936 |
13.279 |
| Reception |
1926 |
0.121 |
| Lower
Shing Mun |
1965 |
4.299 |
| Shek
Lai Pui |
1925 |
0.374 |
| Kowloon |
1910 |
1.578 |
| Kowloon
Bywash |
1931 |
0.800 |
| Plover
Cove |
1968 |
229.729 |
| High
Island |
1978 |
281.124 |
| Outlying
Islands |
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| Shek
Pik |
1963 |
24.461 |
| Total |
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586.048 |
Source:
WSD, 2000
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| 3.4.1.10 |
As
rainfall in Hong Kong may not be evenly distributed
over the water catchment areas, and runoff
will vary based on the absorptive capacity
of the soil, it is difficult to correlate
rainfall with catchment yields. In order to
improve yields and reduce soil erosion, a
programme of afforestation has been pursued
in catchment areas. At present, it is estimated
that approximately 50% of annual rainfall
contributes to surface water resources. The
volume of storage capacity available in Hong
Kong's reservoir system is ample relative
to catchment yield. For example, it is estimated
that it would require 2.5 years to fill the
Plover Cove Reservoir with freshwater from
Hong Kong sources with no drawdown. Therefore
it is the yield rate, which is estimated at
just under 300 Mm3 based on 30 year averages
(WWF 1999) rather than the storage capacity
per se (compare to storage capacity in Table
3.4c above), which limits the total freshwater
resources generated locally. However, it should
also be noted that while storage capacity
is ample relative to existing catchment yield,
storage capacity is also necessary to hold
externally-derived water resources prior to
utilisation. In this sense as the total demand
for freshwater from local and external sources
grows, existing storage capacity will become
increasingly precious. |
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| 3.4.1.11 |
Water
gathering grounds are designated and protected
by WSD in cooperation with the Agriculture,
Fisheries and Conservation Department (AFCD),
Lands Department and Environmental Protection
Department. These catchment areas are essential
for the collection of rainfall for the storage
reservoirs and make up nearly one third of
Hong Kong's land area (WSD 1998). A large
proportion of water gathering grounds also
lie within designated Country Parks which
affords these areas additional protection
under the Country Parks Ordinance (Cap 208). |
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