WSP08828 - Laserfiche WebLink

Home Browse Search

I . !, GROUNDWATER MODEL Model Features --inlet (recharge area) --lake or river ,--lagoon (landfill, wetlands, sewage lagoon, chemical plant disposal) --underground storage tank --wells --piezometers (observation or monitoring wells) --pumping wells (3) --injection wells --artesian well --outlet (discharge area) Materials --gravel --mixture of bentonite and fine sand --fine sand --lenses of course sand and very fine sand --coarse sand below lake, lagoon, underground storage tank Conceots Demonstrated with Model CONCEPT 1: Groundwater is contained underground in the spaces between pieces of gravel, grains of sand or other soil particles, or in cracks and fractures in rocks. Action: Fill one-liter bottle with water and invert it in the inlet. 'Allow water to run through the model. Discussion: Water enters the model. Students will observe the water filling in the gravel. If the sands are dry, they will be able to observe the sand.getting wet. If the sands are not dry, watch .the water rise in the piezometers and pumping wells. Students should note there are no observable rivers, channels, or lakes underground. Underground rivers and lakes rarely exist~ CONCEPT 2: The underground unit of soils and rock materials that hold water are called aquifers. Aquifers are not always uniform either horizontally or vertically. Aquifers may be separated by layers which do not hold or transmit much water. These layers are called confining layers. Action: Look at the sand and gravel layers in the model. Discussion: There is a thin band of material just above the gravel. This band of material allows very little water to pass through it, so it acts as a confininQ laver. The aquifer below the confining layer is the confined aquifer. The aquifer above the confining layer is the unconfined aquifer. 1