Water Resources
Where is our water? * Water makes up 71% of our planet and 2/3 of our body * One in every eight people lack access to clean fresh water * Water is abundant globally, but water we can actually use is rare
Where is our water?
Water * Water is both a renewable and a limited resource Renewable: The Water Cycle Limited: Salt Water and Ice Caps
Water The Hydrologic (Water) Cycle
Water Per capita water resources
Water * Many areas with a high population density do not live near water * Some areas only receive rainwater during a certain season Why do people chose to live there?
Surface Water Surface water: easily accessible freshwater on the Earth's surface (~1% of all water) i.e. ice caps, glaciers, rainfall, snow melt, lakes, ponds, rivers, streams Runoff: water that flows over land and has not been absorbed into the ground
Surface Water River system: a network of connected rivers and streams carrying water that flows downhill according to gravity * Streams can flow into small rivers (tributaries) then into larger rivers, then eventually into a large body of water (lake or ocean)
Surface Water
Surface Water Watershed: includes all of the land area that supplies water to a particular river system (a.k.a. drainage basin)
Surface Water
Surface Water NY Watersheds
Ground Water groundwater: water found below the Earth's surface zone of aeration: layer containing empty spaces (pores) * water can pass through the zone of aeration making it a permeable layer zone of saturation: layer in which pores are filled with water (saturated) water table: boundary between the zone of aeration and the zone of saturation
Ground Water
Ground Water * layers with few or no pores are called impermeable (water cannot flow through) aquifer: sponge-like formations of rock, sand, or gravel that hold water recharge zone: any area where surface water soaks into the ground and reaches an aquifer
Ground Water
Ground Water well: a hole dug into an aquifer to reach groundwater artesian well: a hole dug to reach groundwater confined in an aquifer between two impermeable layers
Ground Water
Ground Water
Ground Water Hydraulic Fracturing (Hydrofracking): a method used to harvest natural gas from shale (Marcellus and Utica shale)
Ground Water
Water Uses The three main ways humans use freshwater are: * Agriculture (~70% globally) * Industrial (~22% globally) * Personal Use (~8% globally) How much water does it take to...... fill the average swimming pool 19,000 gallons water the average suburban lawn 750 gallons take a 10 minute shower 40 gallons flush the toilet 6 gallons run a load of dishes in the dishwasher
Water Uses
Water Uses 77% of freshwater used in agriculture, industry and personal use comes from surface water (lakes, ponds, rivers, streams) * Water has to be pulled from it's source then moved to where it will be used
Surface Water Uses water diversion: moving water from it's source to where humans use it * if agricultural, then it's called irrigation
Surface Water Uses Dam: any obstruction placed in a river or stream to block its flow * Dams create artificial reservoirs Reservoir: large lakes that store water for human use
Water Uses
Water Uses
Water Uses
Water Uses
Water Uses
Water Uses
Water Uses
Surface Water Depletion Drought and overuse leads to dried up rivers and lakes The Aral Sea
Using Groundwater In the US, 26% of all fresh water used is groundwater * 68% of the groundwater is used for irrigation and is increasing * most irrigation is inefficient, why?
Using Groundwater waterlogging: saturating soil in a dry area with water to promote plant growth salinization: the buildup of salts in the surface layers of soil
Using Groundwater groundwater mining: withdrawing groundwater faster than it can be replaced i.e. Las Vegas and the Great Basin
Using Groundwater In Asia and in the Middle East, ground water is falling 3-10 ft. per year * can cause salt water to move into aquifers * surface above aquifers can subside
Solutions to Freshwater Depletion Desalination: removal of salt from seawater, creating fresh water Two ways: * reverse osmosis (artificial membrane) * evaporation (distillation)
Desalination
Desalination
Ways to reduce water use Other ways to reduce demand: Agriculture: drip irrigation Industry: recycling water within the plant Personal: water gardens/lawns at night, turn faucets off, switch to low-flow, fix leaky pipes xeriscaping: use drought tolerant plants
Water Pollution Point source pollution: comes from distinct locations, such as a factory or sewer pipe (you can see it enter the water)
Water Pollution Nonpoint-source pollution: comes from any places spread over a large area (i.e. runoff collecting pollutants)
Water Pollution
Water Pollution
Water Pollution Nutrient Pollution eutrophic: body of water that is high in nutrient content but low in oxygen * Eutrophication can be a natural process (plants decaying in water) or a cultural process (humans polluting water)
Water Pollution cultural eutrophication: nutrient pollution caused by humans wastewater: water that has been used by humans in some way * excess phosphorus (in detergents and fertilizers) from nonpoint-source pollution is a major cause of eutrophication
Eutrophication
Water Pollution
Water Pollution algal blooms: sudden explosions of algal growth caused by excess nutrients
Water Pollution red tide: algal bloom of red algae (phytoplankton and dinoflagellates) * can be caused naturally and culturally
Water Pollution
Water Pollution Toxic-chemical pollution (organic or inorganic) * Petroleum and petroleum products * plastics (Bisphenol-A aka BPA) * Pesticides * Detergents * Heavy metals (usually point source) * arsenic * mercury * lead
Water Pollution
Water Pollution Sediment Pollution: caused by erosion Sediment can cause: * cloudy water * decreased photosynthesis * food web collapse * degraded water quality
Water Pollution Thermal pollution: putting warm water into surface water * warm water cannot hold as much oxygen as cold water * plants and fish cannot tolerate drastic temperature changes or decreased oxygen
Water Pollution Thermal Pollution
Water Pollution Biological Pollution pathogens: disease-causing organisms (bacteria, protozoa, fungi, viruses) * when pathogens enter our air, soil or water, it is called biological pollution * may also include intestinal worms
Water Pollution
Shanghai River Hengliaojing Creek in Shanghai
Water Pollution Groundwater Pollution * usually not discovered until it is found in drinking water * human activity is the main cause * fertilizers, pesticides, leaky underground storage tanks leach below the water table
Water Pollution
Water Pollution Ocean Water Pollution * Oil Spills * Mercury Pollution * Nutrient Pollution (Red Tide)
Water Pollution
Water Pollution
Controlling Water Pollution The Clean Water Act in 1977 * no point source pollution without a permit * set standards for pollution levels
Controlling Water Pollution Drinking Water Treatment 1. Filtration 2. Coagulation 3. Settling 4. Second Filtration 5. Chlorination 6. Aeration 7. Additional Treatment
Controlling Water Pollution Wastewater treatment 1. Raw Sewage enters 2. Screens and grit tank (solid filtration) 3. Primary clarifier (oils, greases, and solids removed 4. Aeration basin (oxygen added for bacteria) 5. Secondary clarifier 6. Filtering and disinfection 7. Effluent discharged into waterways
Controlling Water Pollution
Wastewater Treatment Septic System