Interannual variability in rainfall and its impact on nutrient load and phytoplankton in Myponga Reservoir, South Australia

Abstract

Rainfall in Australia is highly variable and this lends complexity to nutrient loading models. Nutrient loads are important to reservoir management from the perspective of eutrophication and associated algal problems. We describe a flow‐weighted monitoring program, nitrogen and phosphorus nutrient budgets and a hydrology based iterative phosphorus loading model. This model can predict reservoir total phosphorus load in an inter‐annually variable system, Myponga Reservoir, South Australia. Rainfall variability is partially attributed to the El Niño Southern Oscillation (ENSO), and the implications for long‐term forecasting of algal biomass for reservoir management are discussed.

Keywords:

• Rainfall
• flow
• interannual variability
• nutrient load