General advances in river water quality over the past 20 years

Tai Po Kau Stream has benefited from the water quality improvement, which was upgraded from ‘Very Bad’ to ‘Excellent’ in the last 20 years

The general tenor of this report has been one of optimism: in almost all cases, after a raft of remedial measures introduced in the late 1980s and 1990s, river water quality across Hong Kong has improved substantially. In terms of compliance with the statutory WQOs, this has shown itself in a steady rise in compliance rates, as illustrated by the accompanying graph. From just a 49% overall compliance rate in 1986—falling further to 47% in 1987—the rate moved steadily upwards through the 1990s to finally break the 80% level in 2000. Since then it has remained more or less steady, but the 85% compliance recorded for 2005 represented the highest ever since monitoring began.

	WQO compliance in the inland waters of Hong Kong, 1986 - 2005

A similar but perhaps more striking trend has shown itself in terms of Water Quality Index grades, which reflect the general health of rivers. The chart below shows a dramatic move from a situation in 1986 where the majority of stations recorded ‘Bad’ or ‘Very Bad’ grades, to the situation in 2005 when 81% of stations were graded either ‘Excellent’ or ‘Good’.

	Water Quality Index gradings for the inland waters of Hong Kong, 1986 - 2005

Improvements arising from enforcing the Water Pollution Control Ordinance

One recurring theme of this report has been the improvements made possible once the EPD was able to enforce the Water Pollution Control Ordinance (WPCO), which happened progressively across Hong Kong as individual Water Control Zones were established between 1987 and 1996. Regular inspections of dischargers have been and continue to be conducted, and many expedient connections and polluting discharges have been rectified. One way of measuring the impact of the various initiatives is by calculating the ‘pollution load’ being carried by rivers and comparing these pollution loads across time. It is estimated that WPCO enforcement has resulted in an over 80% reduction in the domestic, industrial, commercial and institutional pollution load of the rivers monitored over the past twenty years.

	The impact of the Water Pollution Control Ordinance on river pollution loads
	Regions Before control (kg BOD/day) At end of 2005 (kg BOD/day) Percentage reduction Eastern New Territories (sum of 7 rivers) 13,365 2,566 81% Northwestern New Territories (sum of 11 rivers) 20,095 3,990 80% Lantau Island (Mui Wo River) 15 0 100% Southwestern New Territories and Kowloon (sum of 4 rivers) 7,204 511 93% Total (23 rivers) 40,679 7,067 83%

Improvements arising from the Livestock Waste Control Scheme

As has been demonstrated continually throughout this report, one of the most significant permanent changes to have affected river water quality was the introduction of the Livestock Waste Control Scheme under the Waste Disposal Ordinance in 1988, which had the dual effect of encouraging many farmers to close down their polluting livestock operations, and of requiring those that remained in business to treat their livestock waste to specified standards. It is estimated that 90% of the pollution load from livestock farms has been removed since the regulation took effect. Most of this reduction took place in the rivers of the Northwestern New Territories, where the bulk of livestock farming was concentrated.

	The impact of the Livestock Waste Control Scheme on river pollution loads
	Regions Before control (kg BOD/day) At end of 2005 (kg BOD/day) Percentage reduction Eastern New Territories (sum of 7 rivers) 3.033 0 100% Northwestern New Territories (sum of 11 rivers) 67,187 1,620 98% Lantau Island (Mui Wo River) 178 0 100% Southwestern New Territories and Kowloon (Tuen Mun River) 9,520 0 100% Total (20 rivers) 79,918 1,620 98%

Sewerage improvements

Village house waste water discharged into open channel (before sewer connection)

Village house waste water connected to sewer

Finally, the Government initiated improvements to the sewerage infrastructure by preparing and implementing the 16 Sewerage Master Plans since 1987 that provide blueprints for a comprehensive sewerage network covering all of Hong Kong. The improved sewerage infrastructure has helped minimise sewage pollution in rivers in some areas, especially in the Eastern New Territories. Reviews of the plans have been carried out in the light of new population forecasts and changing patterns of urban development. Further progressive extension of the sewerage system and upgrading of the existing network has also taken place, with clearly positive results for many areas of river water.

Specific initiatives for the future

Hong Kong’s problems with pollution of its river waters are not completely solved yet, as this report has pointed out in various places. Some 14% of monitoring stations still received WQI grades of ‘Bad’ or ‘Very Bad’ in 2005, and the EPD’s target is to have none obtaining such grades. It is clear that this pollution is largely being caused by remaining livestock farms and by the large areas of village housing that are still unsewered.

The Government has put aside more than $8 billion to fund new sewerage programmes in Hong Kong over the next eight or nine years. As public sewers are extended throughout Hong Kong under the various Sewerage Master Plans and their reviews, the EPD will continue to require village house owners to connect to the public sewer as soon as it becomes available, or maintain efficient septic tanks so as to minimise pollution from village areas. The ongoing enforcement of the Water Pollution Control Ordinance is continuing to ensure that expedient connections are eliminated, and other polluting discharges are dealt with quickly and effectively.

Livestock waste should be further reduced under the Government’s Voluntary Surrender of Poultry and Pig Farm Licence Schemes, initiated in 2005 and 2006 respectively. These schemes invite pig and poultry farmers to turn in their Government livestock licences, for which they will be compensated financially. Poultry farmers opting for the scheme have to close down in 2007. Further improvements in river water quality as a result of this initiative are expected in the next few years.

River water quality monitoring

As further changes take place over the coming years, the EPD will continue its comprehensive programme of monitoring and reporting on river water quality so that detailed, scientific information about Hong Kong’s rivers remains widely available to everyone who requires it. Since 1986, the programme has been reporting on the health of Hong Kong’s major rivers, and providing evidence of the critical work necessary to save some of them. Over the years, the programme has been important in helping the Government assess compliance with its Water Quality Objectives, and evaluate how effective its various water quality control measures have been. It has also created a solid basis for the planning of future pollution controls and initiatives. After twenty years of providing this service, the EPD is proud of the programme’s achievements, and is looking forward to many more years of its successful operation.

The EPD will continue to monitor river water quality and provide scientific data for future planning and pollution control work (Photograph taken in the Shing Mun River)