Chapters 15 and 16- Pages 411 to 438 & Supplemental Information Surface Water Systems Chapters 15 and 16- Pages 411 to 438 & Supplemental Information

Hydrologic Cycle You know it as the “water cycle” It is a a model that describes the storage and movement of water between the Biosphere- living things Atmosphere- gases surrounding the Earth Lithosphere- rock Hydrosphere- water on Earth

Major Reservoirs Water is stored in these: Atmosphere Oceans Lakes Rivers Soil Glaciers Snowfields Groundwater

Name some processes which move water through the “water cycle” We know where it is stored, but how does it move throughout the hydrologic cycle ? Name some processes which move water through the “water cycle”

Evaporation- liquid to a gas Condensation-gas to liquid Precipitation- clouds are saturated liquid water falls to ground Deposition Run-off Infiltration Sublimation- solid to a gas Transpiration Melting Groundwater flow

Porosity The percentage of open spaces between rock or sediment particles is POROSITY. If rock has tightly packed particles, it has LOW POROSITY, and a lower ability to store water.  Things that affect porosity: Sorting- poorly sorted rock = low porosity; well sorted = higher porosity Particle packing- the more tightly packed the less porous Grain shape- the more irregular shape the grain of the rock, the more porous it is.

Permeability Pores and fractures in the rock are empty spaces that can be filled with water make the rock porous. Rock is permeable if the empty spaces are connected so the water may flow from one space to the next.

How Earth’s Water is Distributed

Water Input and Output What flows in and out of streams, rivers, lakes, wetlands, seas and oceans on a continuous basis. Inputs- rainwater, ice, snow, any other precipitation. Outputs- Evaporation, use by humans, diversion of water to other contained holding areas.

Aquifers An aquifer is a body of saturated (full of water) rock through which water can easily move. Aquifers must be both permeable and porous and include such rock types as sandstone, conglomerate, fractured limestone and loose (unconfined) sand and gravel.

Aquifer Diagram

Aquifers (cont.)

Earth's aquifers are in danger!

Major U.S. Aquifers

Major cause of depletion of aquifers Widespread overpumping Removing and using the water faster than it can be replenished or refilled.

Residence Times The various reservoirs in the hydrologic cycle have different water residence times. Residence time is defined as the amount of water in a reservoir divided by either the rate of addition of water to the reservoir or the rate of loss from it.

Typical residence times of water found in various reservoirs: Soil Moisture   1 to 2 months Rivers   2 to 6 months  Seasonal Snow Cover   2 to 6 months  Glaciers 20 to 100 years Lakes   50 to 100 years  Groundwater: Shallow   100 to 200 years  Groundwater: Deep   10,000 years Oceans 37,000 years

Water Quality Water quality is a term used to describe the chemical, physical, and biological characteristics of water, usually in respect to its suitability for a particular purpose. Example: Water you wash a car with may not be suitable for drinking. Things that affect water quality: pesticides from lawns and farming; chemicals and waste from factories (VOC’s); pouring chemicals and medications down sinks in homes; air pollution and emissions from motorized vehicles; salt used on roads; bacteria from sewage and waste, etc.

Water Quality Diagram

Land Use Land use and land cover largely determine the type and amount of contaminants entering streams, lakes, and underground pathways, including aquifers. Factors that can affect the movement of contaminants from source areas to wells are: The chemical nature of the contaminant; The physical properties of the soil and aquifer material; The amount and timing of recharge; and The direction and velocity of groundwater movement.

Land Use Diagram

Sustainability Water tables all over the world are falling, as "world water demand has tripled over the last" 50 years. When these aquifers are depleted, food production worldwide will fall. March 2003   Earth Policy Institute Despite its importance, over 1 billion people around the globe still lack access to clean water and thousands perish daily for lack of it. In the natural world, many of our most important aquifers are being over-pumped and half of the world's wetlands have been lost to development. There is a political dimension to water as well: Almost every major river system on the planet is shared by two or more nations, making water a source of international conflict and a matter of national security.

Challenges of fresh water: Uneven distribution on the planet Economic and physical constraints of tapping glacial water Contamination of supplies High distribution costs Regional scarcity solutions are not easy: Reduce demand Move the demand to where water is available. Shift to costly sources, such as desalinization. 70% of the globe is covered by water, but most of it is saltwater. Desalinization can convert saltwater into freshwater, but it is only useful on coastlines and is 15 times more expensive than natural freshwater. 2% of the earth's water is considered freshwater, most of which is locked up in glaciers, permanent snow cover and in deep groundwater.

How we can sustain and improve our water quality Green infrastructure includes rain gardens, porous pavements, green roofs, infiltration planters, trees and tree boxes, and rainwater harvesting for non- potable uses such as toilet use and landscape irrigation. At a much larger scale, green infrastructure includes natural landscape features such as forests, floodplains, and wetlands. “Soft path" solutions: conservation, efficiency, and community-scale infrastructure: can bring clean water to billions who don't have it while helping protect our natural world.

Green Infrastructure Alley renovated with permeable paving located in Chicago, IL A rain garden collects a good portion of parking lot runoff and allows water to seep into the soil.

Buffer strips Control soil erosion by both wind and water. Improve soil quality. Improve water quality by removing sediment, fertilizers, pesticides, pathogens, and other potential contaminants from runoff. Enhance fish and wildlife habitat. Reduce flooding. Conserve energy. Protect buildings, roads, and livestock. Conserve biodiversity. Buffer strips