Secchi Depth

"In this paper, long-term biweekly measurements on the various water quality parameters in Tolo Harbour from year 1982 to 1990, subsequent to the declaration of the area as water control zone, were analyzed and correlated. Correlations have been demonstrated between surface chlorophyll-a concentration with secchi depth and with total nitrogen concentration (TN) in the three sub-zones of Tolo Harbour in Hong Kong with different water quality objectives, The correlation between chlorophyll-a concentration and total phosphorus concentration (TP) is less significant which can be explained by the TN/TP ratio. The correlations are useful for water management, planning and effective pollution control on the land-locked estuary.

In this paper, long-term biweekly measurements on the various water quality parameters in Tolo Harbour from year 1982 to 1990, subsequent to the declaration of the area as water control zone, were analyzed and correlated. Correlations have been demonstrated between surface chlorophyll-a concentration with secchi depth and with total nitrogen concentration (TN) in the three sub-zones of Tolo Harbour in Hong Kong with different water quality objectives. The correlation between chlorophyll-a concentration and total phosphorus concentration (TP) is less significant which can be explained by the TN/TP ratio. The correlations are useful for water management, planning and effective pollution control on the land-locked estuary.

Keywords: Tolo Harbor; correlation; water quality parameters; total nitrogen; total phosphorus; secchi depth; surface chlorophyll-a"

"Tolo Harbour is an almost land-locked waterbody with only one narrow marine inlet to the open sea at Mirs Bay in the Eastern Waters of Hong Kong. Due to its enclosed nature, the waste assimilative capacity is very limited. Besides, it receives substantial pollutant loads from the two sewage treatment plants in the Tolo catchment, livestock rearing industry and other industrial discharges. The building-up of the organic matter and nutrients in the Harbour has caused an increasing occurence of red tides in the past decade. This paper describes the trophic status of the Tolo Harbour based on the monitoring stations results obtained from the Hong Kong Government with particular reference to the chlorophyll-a, secchi depth, total nitrogen (TN) and total phosphorus (TP) concentration.

Tolo Harbour is an almost land-locked waterbody with only one narrow marine inlet to the open sea at Mirs Bay in the Eastern Waters of Hong Kong. Due to its enclosed nature, the waste assimilative capacity is very limited. Besides, it receives substantial pollutant loads from the two sewage treatment plants in the Tolo catchment, livestock rearing industry and other industrial discharges. The building-up of the organic matter and nutrients in the Harbour has caused an increasing occurrence of red tides in the past decade. This paper describes the trophic status of the Tolo Harbour based on the monitoring stations results obtained from the Hong Kong Government with particular reference to the chlorophyll-a, secchi depth, total nitrogen (TN) and total phosphorus (TP) concentration.

Keywords: eutrophication; chlorophyll-a; secchi depth; total nitrogen; total phosphorus"