 Water that sinks deep into the zone of saturation and fills available spaces in cracks and between grains of sediment or rock.

 Less than 3% of Earth’s water is freshwater,  More than 2 % of the freshwater is frozen in glaciers or sea ice,  The accessible freshwater supply is less than 1% of Earth’s total water supply!!!!!

Many Factors Involved!  Porosity  Permeability  Season  Climatic conditions such as drought or flood

Both are influenced by: 1. shape of grains 2. grain size 3. how the grains fit together

 Well sorted material will have high porosity  Poorly sorted material will have low porosity

Lowest porosity is found with igneous rock, and sedimentary rocks like shale.  Igneous rock is crystalline with no pore space. Water can only be found in igneous rock if it has been fractured.  Shale is made with clay cemented together. Clay has flat grains that fit tightly together with minimal space between the grains.

High Permeability =  Impermeable material has water trapped in pore spaces so that the water cannot flow through between the spaces. = Low permeability

Permeable layers of rock and sediment that store and carry enough water to supply wells.  Aquifer near the surface is the water table.  Aquifers that are sandwiched in between permeable and impermeable rocks are called artesian formations.

Water table depth depends on: 1. The amount of rainfall 2. Season 3. Slope of the ground 4. Thickness of the soil 5. Climate 6. Time between rains

 In swamps, lakes, and rivers – the water table is at the surface.  In deserts – the water table is 100s of meters or more below the surface. *Seepage from the water table keeps streams flowing!

 A well can be dug so that it reaches the groundwater to provide freshwater.  The water must be pumped up to the surface.  The well must be deep enough to reach the lowest level the water table may fall during dry weather.

 30 to 70 feet  Water has not filtered very far through the soil,  pH has probably not changed much from that of rain,  The water may be more acidic if it passes through a layer of decaying leaves and may have a “swampy” odor.

 Average 300 to 500 feet  Water has filtered through the ground for a long time,  It will have passed through rock layers that can effect pH - limestone = makes water more basic -granite = make water more acidic

Occurs when groundwater is removed too much or too fast near coastal areas. - the groundwater recharges by pulling in ocean water - this contaminates the freshwater

Even “pure” water contains dissolved chemicals of various kinds. Water Quality = determined based on TDS (amount of total dissolved solids).

 Water is hard when it has a high amount of calcium and magnesium ions.  Hard water is responsible for: - spots on drinking glasses - white scale around bathroom fixtures - scale in water pipes - prevents soap from lathering - laundry looks grey *Scale = mineral build up that can clog pipes

 Iron: -found naturally in water -stains sinks, tubs, clothes rusty orange  Copper: -small amounts found naturally in water -used to control algae -can dissolve from copper pipes if water is acidic -leaves blue-green stains in tubs/sinks

 Chlorine: -not naturally found in water -added at water treatment plants to kill bacteria and control algae -too much smells and tastes bad, can irritate skin, can kill plants and fish  pH: -ranges from 0-14, neutral = 7 -rainwater is typically just below 6 (acidic) -seawater is typically around 8 (basic) -acidic water can lead to corrosion of pipes -basic water contributes to scale and clogging of pipes