Water Source, Storage, Water Quality and Energy Efficiency
Source, storage and water quality
This domain tests whether a water source can meet peak demand, how to size storage, and how quality affects clogging, soil and equipment. It also covers energy efficiency: pump selection, pipe sizing, solar systems and avoiding unnecessary head.
Core rules
- Source yield must exceed peak daily demand, not just average demand; test well yield in the dry season.
- Storage volume = daily demand × days of autonomy, plus fire/utility reserve if required.
- Test pH, EC/TDS, hardness, iron, manganese, carbonate/bicarbonate, chloride, sodium and suspended solids; these indicate scaling, corrosion and clogging risk.
- Use filters and treatment matched to the test, not a universal filter.
- Energy: reduce total head, use efficient pumps and correct pipe sizes, avoid throttling, and consider solar or VFD where the load profile fits.
Worked example
A 1 ha field needs 5 mm/day peak. Volume = 10,000 m² × 0.005 m = 50 m³/day. If the pump runs 5 h/day, required flow = 50 ÷ 5 = 10 m³/h. For two days of storage, tank volume = 50 × 2 = 100 m³. If the pump actually runs only 4 h/day, flow must be 12.5 m³/h, which changes pipe and filter sizing. The lesson is to size storage and pump together.
Traps
Do not size storage on average demand; do not ignore dry-season yield; do not choose a filter without a water test; do not oversize a pump and throttle it; do not forget that EC and pH affect fertigation and soil salinity.