Hydrological Cycle and River System Evaporation – water turning from a liquid into a gas (water vapour). Evapotranspiration – the sum of evaporation from the Earth’s surface together with the transpiration of plants. Groundwater flow – movement of water underground. Hydrological cycle – the cycle of water between air, land and sea. Infiltration – water seeping into the soil. Input – water entering the system through precipitation. Interception – collection of water by vegetation. Precipitation – moisture that falls from the atmosphere in any form. Stores – water stored in lakes, rocks, soil or vegetation. Surface runoff – all water flowing on the Earth’s surface. Sustainable – capable of existing into the long term. Through-flow – movement of water through the soil. Transfers – processes that move water through the system. Transpiration – loss of moisture from plants. Water table – the upper level of underground water