Diagnosing Seasonality Matters More Than Selecting an Algorithm: A Protocol-Controlled Evaluation of Machine Learning Models for Urban Water Demand Forecasting in Nakuru, Kenya
Dalmas Chituyi Wakhusama, Nelson Masese, Moses M. Thiga
The purpose of this study was to evaluate the accuracy and operational suitability of machine learning models for demand-side water forecasting at Nakuru Water and Sanitation Services Company, where 21.7 per cent of the water entering the London Ward network never reached a paying consumer. Four models (ARIMA, FB Prophet, LSTM and Bidirectional LSTM) were re-evaluated on a 964-day operational series under a chronological protocol with a 192-day held-out window, each compared against the naive baseline admissible under its own information set. Models were separated by forecast horizon: lag-based models consume yesterday's realised consumption whereas decomposable models consume only the calendar date, and a rationing schedule must be published in advance. As configured in the parent study, Prophet achieved a mean absolute error of 128.3 m³/day, effectively identical to a straight line fitted to the training data (129.2 m³/day): it had recovered the trend and nothing further. The training partition's autocorrelation showed a dominant 30-day cycle (r = +0.867) and negligible weekly structure (r = +0.203), the reverse of the configured seasonality. Re-specifying Prophet with a cycle length selected on an inner validation split reduced held-out error to 47.7 m³/day, a 62.8 per cent reduction, outperforming the best lag-based model by 16.9 per cent without observed consumption. The study concluded that diagnostic-driven seasonality specification contributed more to forecast accuracy than algorithm choice, and recommends deriving seasonal structure from the training autocorrelation rather than from software defaults.
@artical{d15102026ijcatr15101004,
Title = "Diagnosing Seasonality Matters More Than Selecting an Algorithm: A Protocol-Controlled Evaluation of Machine Learning Models for Urban Water Demand Forecasting in Nakuru, Kenya",
Journal ="International Journal of Computer Applications Technology and Research (IJCATR)",
Volume = "15",
Issue ="10",
Pages ="35 - 42",
Year = "2026",
Authors ="Dalmas Chituyi Wakhusama, Nelson Masese, Moses M. Thiga"}