
%0 Journal Article
%A Royle, RN 
%A King, RJ 
%T Nutrient status of Lake Liddel, New South Wales: mass loadings of nitrogen and phosphurus, industrial modification, and trophic state
%J Marine and Freshwater Research
%D 1992/04/01
%V 43
%N 2
%P 443-455
%K 
%R https://doi.org/10.1071/MF9920443
%U https://www.publish.csiro.au/paper/MF9920443 
%X The concentrations of nitratehitrite-N, Kjeldahl-N and total P in point-source additions to and losses from Lake Liddell (32&#176; 22'S,150&#176; 1'E) were measured fortnightly from September 1987 to September 1988. These data were used in conjunction with flow-rate data to construct a nitrogen and phosphorus budget from Lake Liddell. The annual net point-source loadings of nitrogen and phosphorus were 23 400 and 5700 kg, respectively. There was little relationship between changes in lake nutrient concentrations and fortnightly mass loadings. The mean molar N: P ratio for point source mass additions was 13: 1, whereas that within the lake was 33: 1. These features indicate that within-lake processes were the dominant processes in determining lake nutrient concentrations. Retention in the sediments of a greater proportion of the total P pool than of the total-N pool appeared to be one of these processes. The use of Lake Liddell water in power-station operations resulted in substantial increases in nitrate/ nitrite-N and total-P concentrations in waters returned to the lake. The use of Dillon's model to predict mean annual total-P concentrations from mass loadings indicates that Lake Liddell is on the border between mesotrophic and eutrophic states. 
