Ground Water Vocabulary Porosity – a measure of the % of pores (open spaces) in a material Permeability – a measure of how easy it is to force water to flow through a porous material
More Vocab Aquifer- – An underground formation that is capable of transmitting H 2 O. Water Table – the surface between the saturated zone and the unsaturated zone (zone of aeration)
Unsaturated Zone (Zone of Aeration)- – the zone above the H 2 O table where all the pores are filled with air. Saturation Zone (Zone of Saturation)- – the zone beneath the H 2 O table where all the pores are filled with H 2 O
Types of Aquifers Unconfined Aquifer- – an aquifer that has a free connection upward to the surface Confined Aquifer- – aquifers that are isolated from the surface by an overlying layer of impermeable material called an AQUICLUDE or confining layer Aquiclude : - Impermeable layer separating the unconfined and confined aquifer animation
Recharge Area Recharge – water that falls as precipitation and infiltrates the ground to become groundwater. Recharge Area – The area where permeable soil allows water to seep into the ground. Discharge Area – place where groundwater becomes surface water
Spring- – when groundwater simply bubbles up at the surface of the ground. Naturally occurring Wells – place where groundwater is withdrawn for use in homes, farms, and industry. Human made Artesian Well- – well in which H 2 O rises above the level it was encountered. Must be confined and recharge must exert enough pressure to allow H 2 O to flow upward
Groundwater Flow Ground water moves through subsurface material much like run off – Except a lot more slowly – If the soil is mostly sand or gravel, it can move 5 ft/day Like streams and rivers, ground water moves from high areas to low areas
Gaining Stream- – When ground water is discharged to the surface water. Losing Stream – When water is lost from the surface water to the ground around it.
Water Level Declines Water pumped from the ground-water system causes the water table to lower and alters the direction of ground-water movement. Notice that some water that flowed to the stream no longer does so, thereby reducing the amount of stream flow.
Ground Water Contamination Piezometers- – wells installed to monitor water level and water quality Plume- – a concentration of contaminants that flows along the same path as ground water
What properties of water make it unique? Water can dissolve more substances in greater quantities than any other liquid. – However, this means that water can be easily be contaminated Most groundwater contaminates enter the system from the surface, not at points deep within the aquifer.
Human activities at or near the land surface can contaminate groundwater by moving through the unsaturated zone to the water table. Then contamination can continue to move within the saturated zone and discharge area. Sources of groundwater contamination include: fertilization misuse of pesticides oil spills leaky landfills leaky septic system leaky underground storage tanks
Different chemicals react differently with different soils. Contaminated groundwater may pollute surface water Contaminated surface water can pollute groundwater Water quality can vary within the aquifer