The hydrologic cycle describes the continuous movement of water through precipitation, evaporation, transpiration, interception, infiltration, runoff, and groundwater flow, with precipitation as the principal driver of streamflow relevant to water resources engineering. Precipitation is classified by physical form (liquid: drizzle, light/medium/heavy rain; solid: snow, hail, sleet, glaze) and by the atmospheric lifting mechanism that cools moist air to condensation (frontal, convective, orographic, cyclonic), and is measured as depth or intensity using non-recording and recording (tipping-bucket, weighing, float) rain gauges. Rain gauge network design and data quality rely on statistical measures such as coefficient of variation for determining required gauge density, and on techniques such as normal-ratio estimation for missing data and double-mass curve analysis for correcting inconsistent records caused by station relocation or environmental change.
The hydrologic cycle describes the continuous movement of water through precipitation, evaporation, transpiration, interception, infiltration, runoff, and groundwater flow, with precipitation as the …