TOLO HARBOUR AND CHANNEL WATER CONTROL ZONE STATEMENT OF WATER QUALITY OBJECTIVES

TOLO HARBOUR AND CHANNEL WATER CONTROL ZONE STATEMENT OF WATER QUALITY OBJECTIVES

TOLO HARBOUR AND CHANNEL WATER CONTROL
ZONE STATEMENT OF WATER QUALITY OBJECTIVES

(Cap 358, section 5)

[18 June 1982.]

The water quality objectives set out in the first column of the First
Schedule have been established for the subzones defined in the
Second Schedule set opposite such water quality objectives in the
second column of the First Schedule.

FIRST SCHEDULE

Water Quality Objective Subzone

A. AESTHETIC APPEARANCE

(i) Odours, taints and colours

Waste discharges shall cause no noxious or (i) Harbour subzone
offensive odour or offensive taint or colour in (ii) Buffer subzone.
either waters or edible aquatic organisms in (iii) Channel subzone.
the subzone to be present in concentrations
detectable by bioassay or organoleptic tests.
(ii) Visible matter
Waste discharges shall cause no visible foam, (i) Harbour subzone.
oil, grease, scum, litter or other objectionable (ii) Buffer subzone.
matter in waters of the subzone. (iii) Channel subzone.

B. BACTERIA
Waste discharges shall not cause the level of (i) Harbour subzone.
Escherichia cpoli to exceed 1000 per 100 ml in (ii) Buffer subzone.
waters of the subzone, levels to be calculated as a (iii) Channel subzone.
running median of the most recent 5 consecutive
samples taken at intervals of between 7 and 21
days.

C. CHLOROPHYLL-A
Waste discharges shall not cause the level of Harbour subzone.
chlorophyll-a in waters of the subzone to exceed
10 milligrams per cubic metre, calculated as a
running arithmetic mean of 5 daily measurements
for any single location and depth.

Waste discharges shall not cause the level of Buffer subzone.
chlorophyll-a in waters of the subzone to exceed
10 milligrams per cubic metre, calculated as a
running arithmetic mean of 5 daily measurements
for any single location and depth.

Waste discharges shall not cause the level of Channel subzone.
chlorophyll-a in waters of the subzone to exceed
6 milligrams per cubic metre, calculated as a
running arithmetic mean of 5 daily measurements
for any single location and depth.





Water Quality Objective Subzone

D. DISSOLVED OXYGEN

Waste discharges shall not cause the level of dis- Harbour subzone.
solved oxygen in waters of the subzone to be less
than 2 milligrams per litre within two metres of the
bottom, or to be less than 4 milligrams per litre in
the remainder of the water column.

Waste discharges shall not cause the level of dis- Buffer subzone.
solved oxygen in waters of the subzone to be less
than 3 milligrams per litre within two metres of the
bottom, or to be less than 4 milligrams per litre in
the remainder of the water column.

Waste discharges shall not cause the level of dis- Channel subzone.
solved oxygen in waters of the subzone to be less
than 4 milligrams per litre at any point in the water
column.

E. LIGHT PENETRATION

No changes in turbidity, suspended material, Harbour subzone.
colour or other parameters arising from waste
discharges shall reduce light transmission by
more than 20 per cent of the normal level in the
subzone at any location or any time.

No changes in turbidity, suspended material, Buffer subzone.
colour or other parameters arising from waste
discharges shall reduce light transmission by
more than 15 per cent of the normal level in the
subzone at any location or any time.

No changes in turbidity, suspended material, Channel subzone.
colour or other parameters arising from waste
discharges shall reduce light transmission by
more than 10 per cent of the normal level in the
subzone at any location or any time.

F. pH

Waste discharges shall not cause the normal pH Harbour subzone.
range of any waters of the subzone to be extended
by greater than + 0.5 pH units at any time.

Waste discharges shall not cause the normal pH Buffer subzone.
range of any waters of the subzone to be extended
by greater than + 0.3 pH units at any time.

Waste discharges shall not cause the normal pH Channel subzone.
range of any waters of the subzone to be extended
by greater than + 0. 1 pH units at any time.

G. SALINITY

Waste discharges shall not cause the normal salin- (i) Harbour subzone.
ity range of any waters of the subzone to be (ii) Buffer subzone.
extended by greater than + 3 parts per thousand at (iii) Channel subzone.
any time.

H. SETTLEABLE MATERIAL

Waste discharges shall give rise to no bottom (i) Harbour subzone.
deposits or submerged objects which adversely (ii) Bufler subzone.
influence bottom-living communities, alter the (iii) Channel subzone.
basic Harbour geometry or shipping channels,
present any hazard to shipping or diving activities,
or affect any other beneficial use of the waters of
the subzone.





Water Quality Objective Subzone

1. TEMPERATURE

Waste discharges shall not cause the natural daily (i) Harbour subzone.
temperature range in waters of the subzone to (ii) Buffer subzone.
be extended by greater than + 1.0 degree Celsius (iii) Channel subzone.
at any location or time. The rate of tempera-
ture change shall not exceed 0.5 degrees Celsius
per hour at any location, unless due to natural
phenomena.

J. TOXICANTS

Waste discharges shall not cause the toxicants in (i) Harbour subzone.
waters of the subzone to attain such a level as to (ii) Buffer subzone.
produce significant toxic effects in humans, fish or (iii) Channel subzone.
any other aquatic organism, with due regard to
biologically cumulative effects in food chains and
to toxicant inter-actions with each other.

SECOND SCHEDULE

In this statement-

'Harbour subzone' means all that water bounded by the spring high-water mark of
the contiguous south-western land mass and by lines between the southern tip
of Yim Tin Tsai (22'26'55'N, 114'12'49'E) and the northern tip of Centre
Island (22'26'34'N, 11413 1 1'E) and between the northern tip of Centre
Island and the western tip of Wu Kai Sha Tsui (22'26'20'N, 114'14'02'E) and
more particularly referred to and recorded in the Register;

'Buffer subzone' means all that water bounded by the limits of the Tolo Harbour
Zone to the southwest, by the spring high-water marks on the northern and
southern coasts, and by a line between the northwest tip of Three Fathoms
Cove (22'26'09'N, 114'15'56'E) and the opposite (northern) coast, passing
directly through the northern tip of Bush Reef (22'26'56'N, 114'15'18'E) and
joining the northern coast at Pak Sha Tau Chau (Harbour Island) at
22'2719'N, 114'15'01'E, and more particularly referred to and recorded in the
Register;

'Channel subzone' means all that water bounded by the limits of the Tolo Buffer
Zone to the southwest, by the spring high-water marks on the northern and
southern coasts, and by a line joining the eastern tip of Bluff Head
(22~30'34'N, 114'20'02'E) and the northern tip of Ocean Point
(22'28'50'N, 114'20'20'E) and more particularly referred to and recorded in
the Register.
L.N. 232/82.

L.N. 232/82.

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