Water, water, every where,

Water, water, every where,and all the boards did shrink.Water, water, every where,nor any drop to drink.Water BasicsWater is considered to be the Universal Solvent.As we search for extra-terrestrial life, we look for conditions that would allow water to exist in all 3 phases.Water is continually moving in what we call the Hydrologic Cycle.The Hydrologic Cycle

The Hydrologic Cycle (continued)Evaporation, evapotranspiration, and sublimation is movement of water from the surface of the Earth to the atmosphere.Condensation is when water vapor cools, coalesces into droplets, and becomes visible.Precipitation (rain, snow, sleet, and hail) is movement of water from the atmosphere to the surface of the Earth.Advection is the movement of a substance (in this case, water) by a fluid (in this case, air).

Amount of water moved per day.Average rainfall4,200,000,000,000Evaporation2,800,000,000,000Water Remaining1,400,000,000,000Runoff to Oceans1,300,000,000,000Water Remaining100,000,000,000Agricultural Use60,000,000,000Water Remaining40,000,000,000Industrial Use19,000,000,000Water Remaining21,000,000,000Population of US314,000,000Amount of water available per person67Distribution of WaterMore than 97% of the water on Earth is held in the oceans.Of the water not in oceans, about is held in glaciers.The remaining water is identified as groundwater and is present in lakes, streams, soil, and aquifers.Aquifers are reservoirs of water beneath the surface of the soil.AquifersSubsurface groundwater represents the largest reservoir of fresh-water available for use by humans.Unfortunately, this water is not uniformly distributed and is not necessarily found near population centers or farmland.Two types of aquifers hold this water unconfined and confined.

Aquifers

SpringsWater flowing from subsurface in a, seemingly, continuous supply regardless of weather.The result of the water-table intersecting with the surface of the soil.Hot-springs are types of springs with water temperature that averages 10-15o Fahrenheit warmer than the ambient air temperature.Geysers are types of hot-springs that eject water in columns rising with great force at various intervals. These columns can rise as high as 200 feet.WellsA hole bored into a zone of saturation used to withdraw water.This is frequently used by agriculture to irrigate crops in the US accounts for 65% of groundwater use.As water is drawn from a well, the water table drops and this is known as draw-down. In some cases, this can cause a conical depression of the water table known as a cone of depression.

Artesian WellsNamed after a region in France where this type of well was developed.The pressure from an confined aquifer causes water to rise toward the surface. When the wellhead is below the potentiometric surface, water will freely bubble in a seemingly endless supply (a flowing Artesian well). When the wellhead is above the potentiometric surface, the well will need to be pumped to get water to the surface (a nonflowing Artesian well). Problems with Aquifer DepletionMistakenly treating groundwater as a renewable resource. Recharge of aquifers is contingent on precipitation and pervious surfaces. As we pave large areas of land, this water is diverted into culverts and drainage ditches which leads to streams, rivers, and bays.As a result, aquifers are being depleted and not allowed to be recharged with water.SubsidenceAs water is withdrawn from porous soil and rock, the surface can subside (drop) due to lack of support from below.As the land settles, building, roads, and pipes are affected.

SubsidenceA prime example of this is the San Joaquin Valley in California. The subsurface soil has been drained to irrigate crops.As a result, in some areas the valley floor has dropped more than 28 feet since 1925.

Groundwater ContaminationSaltwater, sewage, leaking petroleum tanks, and other sources of pollution can contaminate wells.

Surface WaterWater on the surface of the Earth can be saline, brackish, or fresh.Saline water is typically found in the oceans, but may appear in inland lakes.The salt concentration for saline water varies from 3.5% in the ocean to more than 27% in inland lakes (Great Salt Lake, UT) and up to 40% in Lake Don Juan (Antarctica).Being salty does not indicate an absence of life. Organisms identified as halophiles thrive in salty water.As water feeding into inland salt lakes drops (diversion for irrigation and municipal use), the salt content rises.Surface Water (continued)Brackish water describes water found in an estuary where salt and fresh water mix.The Chesapeake Bay is the largest estuary in the United States.The Chesapeake Bay watershed covers 64,000 mi.2 and is home to more than 17 million people and includes land from 6 states.The Chesapeake Bay watershed sits atop several large aquifers which would normally provide fresh water for irrigation and municipal use.As the area continues to be developed (farmland converted to housing developments, urbanization), the recharge of these aquifers is inhibited.Baltimore then and now

Surface Water (continued)Freshwater is described as water with a solute concentration below 0.05%.Freshwater is found in ponds, lakes, streams, and rivers.Precipitation at altitude flows toward lower elevations due to the effects of gravity.Velocity of stream flow is a useful tool in determining if a stream could be used for generation of energy.This kinetic energy can be converted into both mechanical (grinding grain, powering machinery) and electrical (hydroelectric dams).StreamflowThe velocity of water is determined by the location within the stream.Centripedal force shifts the area of highest velocity toward the outer bank near a curve in the stream.Water near the banks (sides) flows more slowly due to the effect of friction.Mills and factories dammed the water flow to create sufficient energy near the banks of a stream.

Stream DynamicsWater near the source tends to be swiftly moving, is cold, and contains high amounts of dissolved oxygen.As this water flows downward, the velocity slows, the temperature rises, and the dissolved oxygen level drops.Organisms are well-adapted for the prevailing conditions and when the stream or river is modified, the organisms must move (unlikely), adapt (unlikely), or die (likely).This is cause for concern when considering modifying a stream to use the available kinetic energy.Stream Energy in BaltimoreThe Jones Falls valley was home to dozens of mills and factories that relied on the Jones Falls stream to power their equipment.

Stream Energy in BaltimoreThe mills that lined the Jones Falls produced sailcloth used to power the famous Baltimore Clipper.As a result of the speed difference between these ships and their competitors, Baltimore became a major trading hub for goods in the colonial and post-colonial times.With the opening of the B&O Railroad, Baltimores prominence in trading was cemented.Recently, other ports have been successful in drawing away shipping companies and Baltimore is no longer a leader in goods moved.Advection in StreamsStreams can carry sediment in three ways.In solution (dissolved load), which involves minerals and organic material carried in solution from groundwater.In suspension (suspended load), which is most typical. In suspension, large particles are carried by water currents.By large objects being pushed along the bottom (bed load), large particles, and small debris are carried by stream currents.The amount of debris increases dramatically during periods of flood.Sedimentation

Flooding and FloodplainsSeasonal flooding is to be expected and has always been part of the nutrient replenishment process that leaves soil fertile.Organic material that accumulates in water is carried by rising waters and deposited in fields.As people settled near rivers, flooding became an issue we have tried to control.We build levees and dikes to channel and divert water away from settled areas.These levees are expensive to build and maintain.The Mississippi River

The Mississippi River (continued)

The Mississippi River (continued)

Standing FreshwaterPonds and Lakes can be natural or constructed.If water is held behind an edifice (dike, levee, or dam) or pumped into a constructed lake for future use, it is called a reservoir.The construction of these reservoirs changes the environment and results in extinctions.