Running Water and Groundwater Chapter 5 Running Water and Groundwater Water cycle Running Water Rivers Gaining stream and Losing stream Stream flow Meandering & tributaries Work of streams Erosion & deposition Water beneath the surface Groundwater Who is Stan Hatfield and Ken Pinzke

5.1 Running Water The Water Cycle Water constantly moves among the oceans, the atmosphere, the solid Earth, and the biosphere. This unending circulation of Earth’s water supply is the water cycle.

5.1 Running Water The Water Cycle  Processes involved in the cycle are precipitation • evaporation • infiltration—the movement of surface water into rock or soil through cracks and pore spaces • runoff • transpiration—the release of water into the atmosphere from plants through the ground

5.1 Running Water Earth’s Water Balance  Balance in the water cycle means the average annual precipitation over Earth equals the amount of water that evaporates.

Distribution of Earth’s Water

The Water Cycle Makes no sense without caption in book

Rivers The water flowing in rivers still originates from precipitation, but it is not all from surface runoff. This groundwater seepage is vitally important to the hydrologic settings of the world because it is responsible for keeping water in rivers during times of no rainfall (base flow conditions). Gaining stream - Makes no sense without caption in book

Gaining Stream- river gains water from the groundwater. This diagram is a very general schematic of how groundwater contributes water into surface water (streams, rivers, and lakes). In this case, this is a "gaining stream", which generally gains water from the ground.

Losing Stream – river loses water from the streambed out into the ground. Other streams are "losing streams", which lose water from the streambed out into the ground. Rivers can be gaining and losing at different locations; they can be gaining one time of the year and losing in another time of year.

5.1 Running Water Streamflow  The ability of a stream to erode and transport materials depends largely on its velocity. • Gradient is the slope or steepness of a stream channel.

5.1 Running Water Streamflow • Channel Characteristics - The stream channel is the course the water in a stream follows. - Shape, size, and roughness • Discharge of a stream is the volume of water flowing past a certain point in a given unit of time.

5.1 Running Water Changes from Upstream to Downstream  While gradient decreases between a stream’s headwaters and mouth, discharge increases.  Profile • Cross-sectional view of a stream • From head (source) to mouth - Profile is a smooth curve - Gradient decreases from the head to the mouth

5.1 Running Water Changes from Upstream to Downstream  Profile • A tributary is a stream that empties into another stream. • Factors that increase downstream - velocity - discharge - channel size

Sea Level and Streams

5.1 Running Water Changes from Upstream to Downstream  Profile • Factors that decrease downstream include - gradient, or slope - channel roughness

5.1 Running Water Changes from Upstream to Downstream  Base Level • Lowest point to which a stream can erode • Two general types - ultimate—sea level - temporary, or local • A stream in a broad, flat-bottomed valley that is near its base level often develops a course with many bends called meanders.

Tributaries Rivers and streams begin their lives as smaller creeks, often called "the headwaters". These small tributaries (the small Drippies in the picture) run downhill until they merge to form bigger tributaries (the medium-sized Drippies), which continue merging to form larger rivers (the biggest Drippy). Rivers keep flowing to lower altitudes, towards the oceans.

Stages of a River

5.2 The Work of Streams Erosion  Streams generally erode their channels, lifting loose particles by abrasion, grinding, and by dissolving soluble material.

5.2 The Work of Streams Deposition  A stream’s bedload is solid material too large to carry in suspension.  The capacity of a stream is the maximum load it can carry.  Deposition occurs as streamflow drops below the critical settling velocity of a certain particle size. The deposits are called alluvium.

5.2 The Work of Streams Deposition  Deltas are an accumulation of sediment formed where a stream enters a lake or ocean.  A natural levee parallels a stream and helps to contain its waters, except during floodstage.

Delta & Natural Levees

5.2 The Work of Streams Stream Valleys  Narrow Valleys • A narrow V-shaped valley shows that the stream’s primary work has been downcutting toward base level. • Features often include - rapids - waterfalls

The Yellowstone River Is an Example of a V-Shaped Valley

5.2 The Work of Streams Stream Valleys  Wide Valleys • Stream is near base level. - Downward erosion is less dominant. - Stream energy is directed from side to side. • The floodplain is the flat, low-lying portion of a stream valley subject to periodic flooding.

5.2 The Work of Streams Stream Valleys  Wide Valleys - meanders • Features often include - meanders - cutoffs - oxbow lakes

Rivers with Many Meanders Oxbow Lake formation

Formation of a Cutoff and Oxbow Lake

5.2 The Work of Streams Floods and Flood Control  A flood occurs when the discharge of a stream becomes so great that it exceeds the capacity of its channel and overflows its banks.  Measures to control flooding include artificial levees, flood control dams, and placing limits on floodplain development.

Ohio River Flooding

5.2 The Work of Streams Drainage Basins  A drainage basin is the land area that contributes water to a stream.

 A divide is an imaginary line that separates the drainage basins of one stream from another.

Groundwater

Groundwater

What’s Groundwater? Water that seeps down into the soil and fills in the spaces (pores) between soil particles. In the US alone, groundwater supplies 14.58 % of our fresh water needs.

5.3 Water Beneath the Surface Distribution and Movement of Water Underground 5.3 Water Beneath the Surface  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. • The water table is the upper level of the saturation zone of groundwater.

5.3 Water Beneath the Surface Distribution and Movement of Water Underground 5.3 Water Beneath the Surface  Movement • Groundwater moves by twisting and turning through interconnected small openings. • The groundwater moves more slowly when the pore spaces are smaller.

Porosity Deals with % of available space in given volume of rocks Good porous rock have spaces, same size particles, & are well-sorted. What influences porosity? Particle size and Shape Sorting

 Movement • Porosity Distribution and Movement of Water Underground - The percentage of pore spaces - Determines how much groundwater can be stored

Define What is the difference between porosity and permeability??? Permeability-a measure of a rock or sediments ability to transmit water through interconnected pore spaces. Impermeability-not allowing passage, especially of liquids; waterproof What is the difference between porosity and permeability???

 Movement • Permeability Distribution and Movement of Water Underground  Movement • Permeability - Ability to transmit water through connected pore spaces

Very Porous/Very Permeable Semi-porous/semi-permeable Low porosity/low permeability

Features Associated with Subsurface Water

- Aquifers are permeable rock layers or sediments that transmit groundwater freely

Virginia’s Aquifer System

Aquifer Aquifer: a body of water thru which water flows or is stored. An efficient aquifer is one whose pores are spacious and water is able to flow freely.

Regions of Groundwater Zone of Aeration: between water table and Earth’s surface. Water Table: upper surface of the Zone of Saturation Zone of Saturation: layer of ground where all pores are filled with water.

How does groundwater move? Permeability of the rock in Zone of Saturation Permeability of soil Steepness of the Land Surface

Level of the water table Topography: the water table usually follows the contour of the land.

Wells and Springs Well: a hole dug into the water table and fills up; water must be pumped to surface. Spring: Natural flow of groundwater that flows the earth’s surface. Cold-water Geysers: wells in which water spouts out of an aquifer due to pressure from surrounding water.

5.3 Water Beneath the Surface Springs 5.3 Water Beneath the Surface  A spring forms whenever the water table intersects the ground surface.  Hot Springs • Water is 6–9ºC warmer than the mean air temperature of the locality. • Water is heated by cooling of igneous rock.  Geysers • Intermittent hot springs • Water turns to steam and erupts.

Hot Spring Hot water from below earth’s surface that rises to the surface.

Geyser Eruption Cycle

Geyser A hot spring that periodically ERUPTS!!!

5.3 Water Beneath the Surface Wells 5.3 Water Beneath the Surface  A well is a hole bored into the zone of saturation. • An artesian well is any formation in which groundwater rises on its own under pressure. • Pumping can cause a drawdown (lowering) of the water table. • Pumping can form a cone of depression in the water table.

Cone of Depression

Groundwater and Weathering Mineral (hard) water: water w/ large amounts of dissolved minerals. Soft water: water w/ few dissolved minerals.

5.3 Water Beneath the Surface Caverns 5.3 Water Beneath the Surface  A cavern is a naturally formed underground chamber.  Erosion forms most caverns at or below the water table in the zone of saturation.  Travertine is a form of limestone that is deposited by hot springs or as a cave deposit.

Dissolving of Groundwater Creates Caverns

5.3 Water Beneath the Surface Caverns 5.3 Water Beneath the Surface  Characteristics of features found within caverns • Formed in the zone of aeration • Composed of dripstone • Formed from calcite deposited as dripping water evaporates • Common features include stalactites (hanging from the ceiling) and stalagmites (growing upward from the floor).

Cavern Formation Water causes rock to weaken and weather. Caves join to form Caverns Caves can form when water table is too low & caverns are no longer filled with water

Stalactites Stalactites-water drips from the top and calcite solidifies. Mnemonic: Stalactiteslights hang from the ceiling.

Stalagmite Stalagmite: dissolved calcite deposits on floor Mnemonic: stalagmite “G” from ground

5.3 Water Beneath the Surface Karst Topography 5.3 Water Beneath the Surface  Formed by dissolving rock at, or near, Earth's surface  Common features • Sinkholes—surface depressions - Sinkholes form when bedrock dissolves and caverns collapse. • Caves and caverns  Area lacks good surface drainage.

Sinkhole Formation

Karst Topography Regions where chemical weathering occurs because of groundwater.

5.3 Water Beneath the Surface Environmental Problems Associated with Groundwater 5.3 Water Beneath the Surface  Overuse and contamination threatens groundwater supplies in some areas. • Treating it as a nonrenewable resource • Land subsidence caused by its withdrawal • Contamination

Groundwater Contamination Runoff from industry, fertilizers, pesticides, salt from oceans will all pollute our groundwater.