Chapter 10 S3 Water Underground

Essentials Questions Ch10 S3 1. How does water move through underground layers of soil and rock? 2. How do people obtain water from an aquifer?

When precipitation falls on the ground, what happens to it? Evaporates and/or is transpired (plants) back to the atmosphere runs over surface Infiltrates (soaks) the surface and percolates downward due to gravity becomes ground water

Ground Water As Part of the Hydrologic Cycle

How Water Moves Underground Water underground trickles down between particles of soil and through cracks and spaces in layers of rock. Much of the water in soil seeps downward until it reaches the zone of saturation. The zone of saturation is the area where water fills all of the open spaces in sediment and rock. Groundwater is the water within this zone Groundwater moves by twisting and turning through interconnected small openings. The groundwater moves more slowly when the pore spaces are smaller

Effects of Different Materials Permeable materials allow water to pass through have large connected pores or cracks Ex. sand and gravel allow water to pass easily Impermeable materials don’t allow water to pass through have few or no pores or cracks Ex. clay and granite don’t allow water to pass easily

Water Zones Saturated zone Unsaturated zone Once water reaches an impermeable layer, it is trapped. It can’t soak down any deeper. Instead, it begins to fill up the spaces above the impermeable material. Saturated zone area of permeable rock or soil that is totally filled with water The top of the saturated zone is the water table. Unsaturated zone area of permeable rock or soil that is not saturated The area above the water table contains moisture too but contains air as well. Therefore, the layer of rocks and soil above the water table is unsaturated.

Bringing Up Groundwater Aquifers are permeable rock layers or sediments that transmit groundwater freely (any underground layer of rock or sediment that holds water) A well is a hole bored into the zone of saturation. People can obtain groundwater from an aquifer by drilling a well below the water table.

Using Pumps People use to dig wells by hand and lined with bricks. To bring up water, they lowered and raised a bucket. Today, most wells are dug with well-equipment. Mechanical pumps bring up the groundwater. Pumping water out of an aquifer can lower the water table. Pumping can form a cone of depression in the water table.

Cone of Depression

Relying on Pressure An artesian well is any formation in which groundwater rises on its own under pressure. An artesian well forms when groundwater becomes trapped between two layers of impermeable rock or sediment. If the top layer is punctured, the pressure sends water spurting up through the hole. No pump need.

Springs & Geysers Spring A spring forms whenever the water table intersects the ground surface. (forms where groundwater bubbles or flows out of cracks in the rock) Most springs contain water at normal temperatures.  Hot Springs contain water that is warmed by the hot rocks deep below the surface. The hot water bubbles to the surface in a hot spring.

Springs & Geysers Geyser A geyser is a type of hot spring from which the water periodically erupts. A geyser forms when very hot water that has been circulating deep underground begins to rise through narrow passages in the rock.

Geyser Eruption Cycle

Essentials Questions Ch10 S3 1. How does water move through underground layers of soil and rock? It trickles down between particles of soil and through cracks and spaces. 2. How do people obtain water from an aquifer? by drilling a well below the water table