Water quality of selected lakes in the Auckland Region (1992-2005). ARC Technical Report 268 (TP268). 

G Barnes; N Burns 

2005 

 

 

Report 

Reviews status of Lake Ototoa between 1992-2005. Indicates that the water quality of the Lake has declined and that changes could be cyclic. Conclude that water quality was declining because the average PAC determined from the four key variables (Chlorophyll a, secchi depth, total nitrogen, and total phosphorus) indicated a significant decline in water quality between 1992-2005, with all four deteriorating. However, water clarity data showed a cyclic pattern with El Nino Southern Oscillation (ENSO) phenomenon, thus suggesting observed changes to Lake Ototoa water quality may haven been cyclic, climate driven behaviour rather than a typical linear trend. This could suggest that using linear regressions of PAC adn TLI may not be appropriate measures of change in Lake Ototoa. There has been found deficiencies in the overall dataset (from ARC up to 1998) which may affect results obtained by Barnes & Burns (2005). 

 

Kaipara, south head--Lake Ototoa--water quality--biogeophysical