Ecology Report on Manly Dam
A qualitative and quantitative examination of the limnology of Manly Reservoir Catchment Word Count: 3,916
Abstract
Limnology of the Manly Reservoir Catchment was undertaken to assess the trophic status of the lentic system in the catchment area. Manly Dam is surrounded by urban development and bushland. It is of extreme importance as both a water supply for domestic and commercial use and as a site for a diverse range of flora and fauna. It has a large area of bushland which is an important ecological site. The whole catchment incorporates this bushland, urban areas (including recreational areas) and commercial developments. The extent of the urban development is increasing which is in turn applying pressure to this ecosystem.
The status of the water system can be established into three trophic classes, eutrophic, mesotrophic and oligotrophic. This status was observed at a number of different sites within the catchment area, at varying closeness to human population and the dam itself.
The sites were tested under a number of parameters such as light intensity, temperature, conductivity, turbidity, pH, Dissolved oxygen, nutrients and present species. All of these measurements can be indicative of the trophic status of a lentic water system and used together can be used as an index of the systems overall health and biodiversity.
It was found that there was little difference in the sites regarding dissolved oxygen. However site 3 which was a water body within the golf course showed significant increase in pH. While sites 3 and 4 both sites furthest from the dam showed higher levels of phosphates, turbidity and nitrates, corresponding with less total species showing a high chance of Eutrophication occuring. The sites closest to the dam ie the lake shore and the damn wall showed the lowest readings of nitrate and were within the guidelines of the ANZECC (1992).
Abstract
Limnology of the Manly Reservoir Catchment was undertaken to assess the trophic status of the lentic system in the catchment area. Manly Dam is surrounded by urban development and bushland. It is of extreme importance as both a water supply for domestic and commercial use and as a site for a diverse range of flora and fauna. It has a large area of bushland which is an important ecological site. The whole catchment incorporates this bushland, urban areas (including recreational areas) and commercial developments. The extent of the urban development is increasing which is in turn applying pressure to this ecosystem.
The status of the water system can be established into three trophic classes, eutrophic, mesotrophic and oligotrophic. This status was observed at a number of different sites within the catchment area, at varying closeness to human population and the dam itself.
The sites were tested under a number of parameters such as light intensity, temperature, conductivity, turbidity, pH, Dissolved oxygen, nutrients and present species. All of these measurements can be indicative of the trophic status of a lentic water system and used together can be used as an index of the systems overall health and biodiversity.
It was found that there was little difference in the sites regarding dissolved oxygen. However site 3 which was a water body within the golf course showed significant increase in pH. While sites 3 and 4 both sites furthest from the dam showed higher levels of phosphates, turbidity and nitrates, corresponding with less total species showing a high chance of Eutrophication occuring. The sites closest to the dam ie the lake shore and the damn wall showed the lowest readings of nitrate and were within the guidelines of the ANZECC (1992).