Monday, February 18Looking for Water Elsewhere: Impoundments•As droughts become more common, the idea of creating more impoundments to collect rainfall and water. However, they are not always safe for the public because lots of dams are high risk and not properly inspected.Groundwater•water that resides in rocks and soil beneath the ground•o.8% of Earth’s water•most in aquifers•aquifers = layers of sediment and rock saturated with water•wide variation of volume of water stored•confined aquifer = the water is trapped in between two layers of rock that it cannot penetrate through•unconfined aquifer = water can seep out•characteristics of groundwater•from rain that doesn’t evaporate or run of•percolates through rock to the water table•water table = underground depth where rock and sediment are completely saturated•recharge zone = area from which water enters the water table from surface•discharge zone = groundwater flows to surface•springs, seepsWarm Springs, GA•natural spring with 88-degree water that rushes out at approximately 914 gallons per minuteSapelo Island•used to be a natural spring but since the development of Brunswick, GA, this natural spring dried up•the fountain on Sapelo Island is now dry•point is that people’s actions afect natural water suppliesWater Depletion - Aquifers•Ogalalla aquifer is underneath 8 states and provides drinking water to 82% of the people who live within the aquifer boundary•also used to provide irrigation water for agriculture•balancing agricultural and municipal water use•about 30% of the nation’s groundwater is used for irrigation •in many places, it’s being overused (people are taking water at a faster rate than it can be replenished)•agricultural contamination is a problem•chemicals enter groundwater with rainfall or application of irrigation water •situation that the Geological Survey called “creeping normalcy”•According to a report by the U.S. Geological Survey in 2009, 90% of samples taken from shallow groundwater in Nebraska portions of the Ogallala contained nitrate from fertilizers. The Ogallala is a geologic formation, not an underground lake that can be widely contaminated by a localized spill. Water fills the spaces between sandstone, gravel, clay, and other sediments, which slow the water’s lateral travel. •Ogallala irrigation wells tested - 14% contained one or more pesticides•most common - Atrazine•used in cornfields•hormone disruptor, suspected of retarding fetal development•irrigation wells (5%) contained nitrate levels equal to or in excess of EPA safety standards•excess nitrate levels in drinking water can impair the body’s ability to deliver oxygen in infants (blue baby syndrome)•The Upper Floridian aquifer - primary source of freshwater for 24 counties in coastal Gerogia•first pumped in the 1800s•population pressures in coastal Georgia - saltwater intrusion below the surface•coastal aquifers have some naturally occurring saltwater intrusion•overpumping causes saltwater to intrude•withdrawals support public supply, industry, and irrigation•salt water intrusion in Brunswick, Georgia•salt contamination increases demands for the remaining freshwater and restricts the use of the aquiferWater Pollution•any change in water quality that aversely afects organisms•types:•chemical input•sediment input •thermal input •supply impacts (dams)Sources: Point vs. Non-Point•point sources •end of pipe pollution •effluent from a particular site •sources: •factories •sewage treatment plants•mines•oil tankers and oil wells•factories: oil refineries, pulp and paper mills, chemical, electronics or auto manufacturers•pollution is one or more pollutants contained in discharged water (effluents)•direct discharge into waterbody•treat and release•wastes to sewage treatment plants for treatment •combined sewer system - common in older municipalities•raw sewage can carry human bacteria and viruses•combined sewer overflows contain chemicals, oils, and other wastes•non-point sources •farms, forests, lawns streets •hard to find exactly where it’s coming fromAtlanta’s Problem: Municipal Water Supply System•joint storm and sewer lines built in the late 1800s•the larger problem is that the system can handle the demand due to:•new hookups strain the system•increased asphalt and concrete that prevents water from infiltrating soil and run of into storm sewers•broken pipes - discharge can occur through breaks•clogs from oil/gas•tree roots in broken pipes•In 1995, the Environmental Protection Agency, the Georgia Environmental Protection Division, the advocacy group Upper Chattahoochee Riverkeeper, and a citizen brought suit against the city of Atlanta for multiple water-quality violations. •The city settled the lawsuits with a $3.2 billion upgrade plan. •In 1998, the Department of Justice/EPA/EPD decreed that Atlanta must develop and implement a plan to stop combined sewer overflows from polluting the Chattahoochee River byNovember 2007. •This was later extended to 2014 and now 2027.•The city has funded the work through:•bond issues, •raising customers’ water and sewer rates by 45%,•a one-cent sales tax, and•a commercial paper program with a $1.2 billion line of credit. •Atlanta projects include construction of a deep-rock tunnel storage and treatment system to capture overflow from the sanitary and combined sewers and direct it to treatment facilities. Any overflows are screened, disinfected, and dechlorinated before discharge. •First tunnel project (Nancy Creek Tunnel) - Clayton Water Reclamation Center completed in