Is the Weather Making your Demand Hard to Predict? Planning for Demand Variability Due to Weather


  • Reed Palmer, Jack Kiefer - Hazen and Sawyer
  • Kenneth Waldroup - City of Raleigh

Forecasting water demand is an important activity for any water utility whether the outlook period is for tomorrow, next week, the upcoming summer, or for a long-range planning program looking many years into the future. There are a number of drivers for utility demand including weather, the economy, pricing, and water efficiency among others. On time scales as short as a day or as long as a year, weather variations can significantly influence a utility’s total demand. This presentation will describe a technique used to quantify a demand range attributable to a region’s weather fluctuations and describe several applications of this knowledge to utility planning activities. The technique centers on two primary weather parameters, temperature and precipitation, which together with a sample period of historical demand can be used to estimate inter-annual and month-to-month demand fluctuations. The authors demonstrate its application to several utilities in North Carolina undertaking different planning activities. Three utilities applied this technique to establish the magnitude of demand depression that recent wet years have had on the overall demand growth. Of these, one was able to reconfirm the need for addition water supplies over the coming decades despite relatively flat demand growth during the past 8-10 years. Two others were able to demonstrate the need for water plant expansions to cover anticipated maximum day demands that could be expected to occur within the next decade. The fourth utility applied the technique post-hoc to evaluate the effectiveness of mandatory conservation measures taken during the 2007-08 drought to more accurately estimate its ability to conserve during future drought events.

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Horizons Fall 2017 (pdf)

Horizons showcases significant water, wastewater, reuse, and stormwater projects and innovations that help our clients to achieve their goals, and can help you achieve yours. Articles are written by top engineers and process group leaders, demonstrating and explaining the beneficial application of a variety of technologies and tools.

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