In many cases, the modeler can simply grab the latest calibrated model from the master planning study and apply it to address an operational problem. However, water and wastewater systems are constantly evolving as new facilities are brought online, customers are added, or adjustments are made to system operations.

In general, water quality tends to deteriorate with water age as disinfectant residual decreases, microbial activity increases, and disinfectant by-products increase. Locations at the end of long dead-end pipes generally have the highest water age and hence the poorest water quality.

Pumps & Systems magazine had a good article recently on the need to calibrate pressure gauges. They pointed out that pressure gauges (and sensors) tend to lose accuracy over time; specifically, that gauges should be calibrated at a regular interval, suggesting annually as typical.

Pressure zones are important but can be difficult to understand. OpenFlow WaterGEMS and OpenFlows WaterCAD makes creating and managing pressure zones easy.

In the blog A Multi-Species Decay Model to Support Cost-Effective Chlorination in Distribution Systems, a cost-effective chlorination strategy is defined as the least-cost combination of doses (locations and rates) that achieves effective chlorination for a given stable flow regime and water temperature. Searching for such a strategy requires extended-period simulations for many dosing location and rate combinations.

Water utilities are required to achieve effective chlorination by maintaining a detectable free chlorine concentration to the system extremities. The initial dose required to inactivate pathogens may subsequently completely react with chemical contaminants remaining after treatment but before the water reaches these extremities. Then, either the initial dose must be increased, or booster doses are required at intermediate locations.

Electromagnetic Pulses (EMPs) are short bursts of electromagnetic radiation. While small EMPs can occur normally, large EMPs can interfere with or even destroy electric power supplies and electronic equipment. EMPs can occur naturally from solar flares or lightening, or they can be created by human threat actors. They can be produced by high and low-altitude nuclear weapons; geomagnetic disturbances (GMD) caused by coronal mass ejections; and by small portable devices employed to produce electromagnetic interference (IEMI).