Operational Challenges in Maintaining Potable Water Quality: A Case Study on Water Age and Flushing Failures in Riyadh’s Strategic Pipelines

This dataset contains the full manuscript and supporting information for a case study investigating potable water quality deterioration caused by prolonged stagnation in a newly constructed 1400‑mm trunk main in Riyadh, Saudi Arabia. The pipeline remained stagnant for more than 30 days during peak summer temperatures (38–44°C) due to incomplete commissioning and the absence of flushing and disinfection procedures. Field measurements showed complete chlorine depletion (0.00 mg/L), elevated turbidity (4.8 NTU), and significant microbial activity, including HPC counts exceeding 500 CFU/mL. Visual inspection during drain‑down confirmed early biofilm development on the pipe walls.

The dataset documents the operational, hydraulic, and public‑health implications of this event and compares the findings with international guidelines from WHO, EPA, AWWA, and Saudi MEWA standards. The analysis highlights how high temperatures, long water age, and lack of flow accelerate chlorine decay, promote biofilm growth, and increase turbidity in large‑diameter transmission mains. The study also examines the hydraulic challenges of achieving effective flushing velocities (≥1.5 m/s) in large pipes, where required flow rates exceed 2.3 m³/s.

The dataset includes:
• The full manuscript (PDF)
• Field observations and measured water‑quality parameters
• A summary of commissioning requirements and deviations
• Discussion of risks under PPP contractual frameworks
• Recommendations for utilities, including improved flushing strategies, automated water‑age monitoring, and enhanced commissioning controls

This dataset aims to support researchers, water‑utility engineers, and policymakers in understanding the risks associated with stagnation in large transmission pipelines and in developing more resilient commissioning and water‑quality management practices.