Water Sources, Supply, and System Layout
Sources, yield, and layout
A Class I operator must separate groundwater from surface water and know how each shapes design. Groundwater sits in aquifers - unconfined (water-table) and confined (artesian) - and is usually low in turbidity and microbes but may carry iron, manganese, hardness, arsenic, or nitrate. Surface sources (rivers, lakes, reservoirs) vary seasonally in turbidity, algae, and temperature and normally need full treatment. Safe yield is the long-term withdrawal a source can sustain; exceeding it causes declining levels, subsidence, or saltwater intrusion in coastal wells. Wellhead and watershed protection are the first barriers, and source choice drives treatment, storage, and pumping.
Transmission mains move water from source and treatment to storage and distribution. Distribution mains form a grid or looped network that provides redundancy, better fire flow, and fewer dead ends; tree (branching) systems create dead ends where sediment collects and chlorine residual decays. Pressure zones follow topography, with pressure-reducing valves or booster stations at boundaries. Fire flow depends on main size, looping, and stored volume, not just pump capacity.
Traps: assuming an artesian well needs no pump (it may flow only if pressure is sufficient); confusing permitted capacity with safe yield; forgetting that looping is a water-quality measure as well as a hydraulic one; treating storage as only a pressure device rather than emergency and fire supply.
Rule of thumb: psi × 2.31 = feet of head, and 100 ft of head ≈ 43.3 psi. Always convert elevations and pressures to the same units before comparing them.