Future Climate: What does it mean for reservoir water quality Future Climate: What does it mean for reservoir water quality? WRA 1050/ WaterRF 4468 Comprehensive assessment of the Impacts of Climate Change on Reservoir Water Quality in a Range of Climatic Regions Leon van der Linden SA Water, Research and Innovation Water RA Forum, WA, November 2013

Business Issue: Problem Statement Climate change Water security (quantity and quality; supply and demand), operational costs and asset longevity. Impacts SA Water source waters. Presents additional challenges to planning and operations. “Managing these changing environmental conditions pose challenges in unchartered territory and require long-term planning based on scientifically sound research.” - Denise Kruger, Water Research Foundation, Chair of Board of Trustees.

Climate: Variability and Change Variability: interacting geophysical phenomena Our understanding is still developing Instrumental record has limited temporal and spatial extent Proxies: flood debris, germination events, etc Global circulation models still have major uncertainties; the science is underpinned by real data Understanding the past and present weather is challenging

Projected temperature rises for South Australia 2020 2050 2080

Projected precipitation for Southeastern Australia 2020 2050 2080

Post, D. , Chiew, F. , Teng, J. , Wang, B. & Marvanek, S Post, D., Chiew, F., Teng, J., Wang, B. & Marvanek, S. (2012) Projected Changes in Climate and Runoff for South-eastern Australia Under 1 °C and 2 °C of Global Warming. A SEACI Phase 2 Special Report.

Potential climate change impacts to the water business Cost Assets / Investments Energy (pumping, desalination and price) Coagulants Disinfectants Compliance Pathogens / DBPs / Toxins Outfalls Greenhouse gas emissions Customers Aesthetics / tastes and odours Demand Water Quality Impacts

Projects on climate change impacts on water quality Water Research Foundation / Water Research Australia: Comprehensive assessment of the impacts of climate change on reservoir water quality in a range of climatic regions VT, NCKU, UA Literature review; integrated modelling analysis Goyder Water Research Institute: An agreed set of climate projections for South Australia Task 4 – Development of an application test bed UniSA, SARDI, UA, FU, DEWNR Reservoir model sensitivity analysis; downscaling product evaluation

Potential climate change impacts on water quality Elevated temperatures Impacts on catchment biogeochemistry Increased stratification Release of ions from the sediments Growth of cyanobacteria Less frequent but more intense rainfall Altered flow regimes Increased transient inputs of: sediment pathogens organic matter Fe Mn PO4 WTP

Risk assessment Historically valid coupled model Water quality Skilled GCM Climate Projections Change Statistics Distributions Variable correlation Weather Generator meteorology demand change Historically valid coupled model land use change Catchment Data Reservoir Data Water quality scenarios Hydrological Model Hydrodynamic Model Water quality Model Catchment and Reservoir Planning Options Expert knowledge Climate change impacts on water quality Risk assessment

Model Sensitivity – ELCOM-CAEDYM – Happy Valley Res. Overlay: Empirical sensitivity of monthly average chlorophyll to temperature anomaly

Integrating impacts into risk management framework

Risk Matrix - Defines management vigilance

Anticipated Outcomes Identification of risks to water quality Reservoir stratification Rainfall extremes Catchment impacts Develop methods to quantify risks Contribute to corporate risk management Provide information for long term planning Comprehensive climate change scenarios Quantified changes in risk Hi Leon,   The Outcomes required from the SA water Corporate Business Plan related to Climate Change are: Compliance with relevant legislation, regulations standards and voluntary agreements A suite of tools for climate change scenario planning for impacts on source water, water quality, assets, customer demand, and price (adaptation). The second one is the relevant one for your study The long term 2023 goal identified is: Develop sound knowledge and improved forecasting on climate variability and determine their impacts on SA Water’s operations, including water security (quantity and quality), waste water treatment, land management