Short-term water demand forecast considering SPEI and climate indices

Water demand is influenced by a number of factors with temperature and precipitation being among the key elements. Especially during longer dry and heat periods, water demand changes due to changes in consumption patterns, filling of swimming pools and increased garden irrigation. 

Therefore, a reliable water demand forecast is very important for Austrian water utilities in order to be able to react to increasing water demand peaks. In a previous study (Stelzl A.; Fuchs-Hanusch D.), long-term forecasting models were developed using climate indices. The developed modeling approach achieved satisfactory results in terms of prediction accuracy. However, it was found that the effect of dry and hot periods could not yet be modeled with sufficient accuracy. For this reason, this study attempts to improve the modeling approach by adding the Standardised Precipitation Evapotranspiration Index (SPEI) as an additional parameter into the model. In addition, the new work targets short-term water demand forecasts to provide water utilities with a basis for taking timely action to cope with peak water demand or inform customers about necessary water saving measures. Current short-term forecasts of the meteorological situation (e.g. SPEI) are provided by Land Steiermark (Land Steiermark, 2024). The water demand forecasting model developed in this study can be applied to these short-term forecasts.

In a first step, the relationship between SPEI, climate indices and water demand was determined. The SPEI and the climate indices are calculated from historical weather records for the selected study sites. During the model building process, a stepwise forward variable selection process is carried out to determine the significant parameters. The SPEI was found to be a significant parameter for water demand forecasting. The model building process and evaluation is still ongoing. It is expected that the use of the SPEI will improve the accuracy of peak water demand forecasting model. The final results will be available at the conference.

References:

Stelzl, A.; Fuchs-Hanusch, D. Forecasting Urban Peak Water Demand Based on Climate Indices and Demographic Trends. Water 2024, 16, 127. https://doi.org/10.3390/w16010127

Land Steiermark, A 14 (2024) Dürreindex - Wasserversrogung. [online] https://www.wasserwirtschaft.steiermark.at/cms/beitrag/12903795/173854972. (Accessed:  10. January 2024)