What causes groundwater to flow downward?
Water falling on the ground surface as precipitation (rain, snow, hail, fog, etc.) The water in the unsaturated zone may be used by plants (transpiration), evaporate from the soil (evaporation), or continue past the root zone and flow downward to the water table, where it recharges the groundwater.
Does groundwater flow up or down?
As already noted, groundwater does not flow in straight lines. It flows from areas of higher hydraulic head to areas of lower hydraulic head, and this means that it can flow “uphill” in many situations.
What direction does groundwater flow?
To first approximation, groundwater flows down-gradient (from high to low hydraulic head). As is the case with surface water, or a ball rolling down a hill, the water flows in the direction of the steepest gradient, meaning that it flows perpendicular to equipotentials.
Can groundwater flow upwards?
Groundwater can actually move upward or downward. Groundwater can move upward against gravity because the hydraulic head at any point is a combination of both elevation and pressure. Hydraulic head is the level to which groundwater will rise in a well. Groundwater flows from high hydraulic head to low hydraulic head.
What is groundwater storage?
Groundwater storage refers to the holding or storing of groundwater underneath the Earth’s surface.
What forces cause groundwater flow?
The two most important forces controlling water movement in rock are gravity and molecular attraction. Gravity causes water to infiltrate until it reaches impermeable zones where it is diverted laterally. Gravity generates the flow of springs, rivers, and wells.
How does water flow through an aquifer?
After entering an aquifer, water moves slowly toward lower lying places and eventually is discharged from the aquifer from springs, seeps into streams, or is withdrawn from the ground by wells. Groundwater in aquifers between layers of poorly permeable rock, such as clay or shale, may be confined under pressure.
How does water enter the groundwater system?
Water seeps into the ground much like a glass of water poured onto a pile of sand. As water seeps into the ground, some of it clings to particles of soil or to roots of plants just below the land surface. Water seeping down from the land surface adds to the ground water and is called recharge water.
What direction does the water table slope?
The water table slopes downwards towards the north-east (Figure 5a). c. Undulations in the water table tend to follow undulations in the topography. The twomajor topographic features are the Ryton and Poulter river valleys, beneath which there are corresponding dips in the water table.
Do river basins flow down from aquifers?
What I mean is, groundwater contributes to streams in most physiographic and climatic settings to a certain degree; some of the water flowing in rivers comes from seepage of groundwater into the streambed. The water flowing in rivers still originates from precipitation, but it is not all from surface runoff.
What does groundwater storage mean in the water cycle?
Groundwater storage– water existing for long periods below the Earth’s surface. The water is still moving, possibly very slowly, and it is still part of the water cycle. Most of the water in the ground comes from precipitation that infiltrates downward from the land surface.
What is groundwater water cycle?
Groundwater is a part of the natural water cycle (check out our interactive water cycle diagram). Some part of the precipitation that lands on the ground surface infiltrates into the subsurface. Water in the saturated groundwater system moves slowly and may eventually discharge into streams, lakes, and oceans.
What controls the direction of groundwater flow?
The driving forces that control groundwater flow are a bit more complicated than those controlling flow in rivers and streams. As you learned in Module 3, surface water flows downhill due to gravity, and the flow direction is defined by the topography.
What direction does groundwater flow in the Skagit River?
Groundwater flow in the alluvial and recessional outwash aquifer generally moves in a southwestward direction away from the Skagit River and towards the Swinomish Channel and Skagit Bay ( figs. 5–8 ).
What causes groundwater flow patterns?
Groundwater-Flow Directions. These flow patterns likely reflect variations in hydraulic conditions within the aquifer resulting from spatial variations in aquifer material properties (clay, silt, and sand). Local groundwater withdrawals and agricultural drainage systems also may influence the groundwater-flow patterns.
What processes are involved in groundwater recharge and discharge?
Processes that contribute to groundwater recharge include precipitation, streamflow, leakage (reservoirs, lakes, aqueducts), and artificial means (injection wells). Groundwater discharge is any process that removes water from an aquifer system. Natural springs and artificial wells are examples of discharge processes.