ENV100Y5 Lecture : env100 note 33.docx

• School: UTM
• Department: Environment
• Course: ENV100Y5
• Professor: murk

Document Summary

Groundwater is earth"s largest unfrozen freshwater reservoir: aquifer = underground reservoirs of rock and sediment that hold groundwater, water table = upper surface of water in an aquifer, groundwater may stay for thousands of years in an aquifer. In canada there is much more water underground than on the surface: 26% of canada"s population depends on groundwater (8 million people, 2/3 are rural users. Groundwater flow is controlled by gravity: water table mimics topography, where water table intersects surface = surface water, recharge = water flows into an aquifer via precipitation/infiltration, discharge = water flows out of an aquifer via percolation/streams/springs/ocean. Water use has increased four-fold over the past 40 years: per capita access to clean water has declined, water supply, water-stressed = 1000-2000 m3/person/day (overuse, water-scarce = < 1000 m3(2700 l)/person/day (unavailability) 42 countries water-scarce: 1. 2 billion without access to clean water, 1. 7 billion without access to sanitation, most are in developing nations.