The Hydrologic Cycle Constantly Redistributes Water Water cycles through environment Describe cycle: evaporation from moist surfaces/water precipitation run-off (rivers/lakes); soil percolation (ground water) through living organisms solar energy drives the hydrologic cycle water and sunlight are unevenly distributed around the globe, thus water resources are very uneven
Water in the World water covers 71% of earth’s surface
Unique Properties of Water due to molecular structure O HH - ++ a polar molecule - excellent solventpolar molecule adhesion hydrogen bonding between water molecules between water and other molecules cohesion O HH - ++ O HH - ++ O HH - ++ tensile strength capillarity - from cohesion and adhesion
Reasons for dams? flood control electricity generation water source recreation
I tell you gentlemen; you are piling up a heritage of conflict and litigation of water rights, for there is not sufficient water to supply the land. –John Wesley Powell (1893) Case Study: Ch 11, When will Lake Mead go dry?
CASE STUDY: When will Lake Mead go dry? l 11-13
l 11-14 LAKE MEAD, Nev. — The sinuous Colorado River and its slew of man-made reservoirs from the Rockies to southern Arizona are being sapped by 14 years of drought nearly unrivaled in 1,250 years. Colorado River Drought Forces a Painful Reckoning for States, New York Times, MICHAEL WINES JAN. 5, 2014MICHAEL WINES JAN. 5, 2014 The Colorado River System
Unique Properties of Water 1. liquid over wide range of temperatures due to cohesion boiling = 100°C (212°F) freezing = 0°C (32°F) 2. high heat capacity (slowly changes temperature) stores heat well and can resists temperatures changes coastal areas have less temperature fluctuations than continental areas moderates earth temperature 3. requires much energy to evaporate skin furnishes heat and thus cools body
Unique Properties of Water 4. great solvent (of polar compounds) polarity of water molecule keeps ions apart salt (NaCl) ionizes in water
Unique Properties of Water 5. surface tension and high wetting ability cohesion and adhesion cause water to rise in plants as water evaporates from the leaf surface, a column of water is pulled upward from the soil water
Unique Properties of Water 6. Expands when freezes ice floats (insulates) 7. Density increases as temperature decreases: most dense at 4°C bodies of water (lakes and streams) remain liquid in winter turnover can occur in lakes in spring and fall
Surface Water water that remains on earth’s surface as a result of precipitation water in streams, lakes, wetlands, reservoirs watershed land region draining into a body of water Stagecoach Lake in lab we determined that lake’s watershed Impact of Rachel Carson’s Silent Spring
Biological Amplificaiton 10,000,000X increase in concentration Rachel Carson, 1962 Silent Spring
Biomagnification cont’d Clear Lake, California (90 mi N San Francisco) copious numbers of gnats (not a mosquito) 1949 - DDD (DDT relative) applied to lake 1 part DDD : 70,000,000 parts water 1/70 parts per million 1954 - control repeated (now not as affective) 1 part DDD : 50,000,000 parts water 1/50 parts per million 1955 Western Grebes starting to die 1957 - 3rd wave of DDD application more Western Grebes die; analysis of bird tissue: 1600 parts DDD per million 112,000 X increase in concentration
Ground Water water that percolates downward through spaces in soil and rock zone of aeration upper soil layers that hold both air and water zone of saturation region of rock and soil that always maintains water in the spaces water table begins at the zone of saturation aquifer water-saturated layers of rock, sand, gravel through which groundwater flows relatively impermeable layers (rock & clay) keep water contained in aquifer recharge area - land area that has water percolating downward into the aquifer
Groundwater Problems Two kinds of problems reduce groundwater’s utility: Discharge problems Groundwater pollution Withdrawal problems Depletion Land subsidence Salt water intrusion Groundwater is very vulnerable to pollution, which is costly and time- consuming to clean up. Withdrawal problems occur because human pumping can remove water from aquifers much faster than they recharge.
Ogallala Aquifer world’s largest know aquifer irrigation increases yields 2X to 3X central pivot irrigation removes much water from the aquifer essentially nonrenewable (slow recharge rate) pumped 8-10X times faster than recharge rate expect 25% reduction by 2020 What are solutions?
Pollution of Water Sources turn to neighbor and think of as many kinds of water pollution as possible I’ll give you a short time to do this (minute or less) The group with the most, of course, wins
Classes of Water Pollution 1. disease-causing agents (pathogens) bacteria (causing dysentery, enteritis) coliform bacteria (Escherischia coli = E. coli) normally live in intestinal tract of animals indicators of fecal contamination if present in water 0 bacteria/100ml water for drinking - WHO recommendation 200 bacteria/100ml water for swimming - EPA recommendation viruses infectious hepatitis parasites protozoans (Giardia) worms (Schistosomiasis) Schistosomiasis occurrence Giardia
Classes of Water Pollution 2. Oxygen-demanding wastes wastes that decompose (organic) by oxygen requiring (aerobic) bacteria the bacteria thus reduce DO in water this impacts all aquatic life - food chain (web)
Classes of Water Pollution 2. Oxygen-demanding wastes Biological Oxygen Demand is the amount of oxygen required for microbial metabolism of organic compounds in water high organic compounds increases BOD, leading to low quality water microorganisms feed on organic compounds in water feeding depletes oxygen in water more organic compounds = greater feeding reduces oxygen in water greatly larger organisms with gills have inadequate oxygen to breath restricts biodiversity in water
Classes of Water Pollution 3. water-soluble inorganic chemicals acids, salts, compounds of toxic metals (mercury & lead)
Classes of Water Pollution 4. Inorganic plant nutrients water-soluble nitrates, phosphates from where do these originate?
Classes of Water Pollution 5. organic chemicals oil, gasoline, plastics, pesticides, cleaning solvents, detergents Jan 9, 2014: Elk River (Charleston, WV) MCHM (4-methylcyclohexanemethanol), a chemical foam used to wash coal to reduce pollution; 7500 gal upstream from drinking water intake and distribution center Pipeland oil leaks – many each year, most with no attention (Arkansas – Mar 29, 2013, Missouri – Apr 30; North Dakota – Sep 29) BP Deepwater Horizon oil spill (Apr 20, 2010) Exxon Valdez oil spill – tanker, Mar 24, 1989)
Classes of Water Pollution 6. sediment or suspended matter soil erosion 7. water-soluble radioactive isotopes 8. thermal pollution l cooling of industrial and power plants l coal, nuclear & oil fired electric plants create steam to drive turbines
Classes of Water Pollution 9. genetic pollution introduction of non-native species Water hyacinth has been called the worst aquatic plant in the world! It is native to South America, but has been naturalized in most of the southern United States and in many of the world's subtropical and tropical climates. It has a tremendous growth and reproductive rate and its free-floating mats cause substantial problems when it grows outside of its native range. Millions of dollars are spent each year in the United States for its management. Water hyacinth has been widely distributed because of the beauty of its large, purple to violet flowers.
Sewage Treatment Rationale More than 500 pathogenic bacteria, viruses, and parasites can travel from human or animal excrement through water. Natural Processes In many areas, outdoor urination and defecation is the norm. When population densities are low, natural processes can quickly eliminate waste. Artificial Wetlands Are a Low Cost Method Natural water purification Effluent can be used to irrigate crops or raise fish for human consumption.
Lincoln Wastewater Facilities Underneath and throughout Lincoln are over 1,000 miles of sanitary sewer lines and 16 pumping stations 114 employees at solid waste and wastewater facilities Theresa Street Facility 27 th & Cornhusker 20 million gallons of water daily Northeast Facility 5 million gallons of water daily Combined this would fill Holmes Lake in 3.5 days
Municipal Sewage Treatment 1. Primary Treatment - Physical separation of large solids from the waste stream screening, pumping, grit removal get the big stuff out material collected hauled to landfill primary clarification removes settleable solids removes floatable materials like grease 2-4 hrs primary clarifier
2. Secondary Treatment - Biological degradation of dissolved organic compounds Biological Treatment Aeration basin removes pollutants with bacteria and protozoans must be aerated 8 hrs Secondary clarification separates treated wastewater from microorganism (from aeration basin) Disinfection chlorination or UV light Municipal Sewage Treatment
2. Solids processing - Biological degradation of dissolved organic compounds solids digestion anaerobic digesters to stabilize organic solids produce methane gas (CH 4 ) which can power turbine to generate electricity 18-20 days solids dewatering removes excess water solids (organ rich material) Municipal Sewage Treatment Belt Filter Press Dewatering Anaerobic Digesters
2. Solids processing - Biological degradation of dissolved organic compounds land application soil amendment and fertilizer alternatively dewatering is replaced by collecting liquid and using it as fertilizer on city owned land Municipal Sewage Treatment Subsurface Biosolids Injection
Municipal Sewage Treatment 3. Tertiary Treatment - Removal of plant nutrients (nitrates and phosphates) from secondary effluent. Chemicals, or natural wetlands Lincoln does not have tertiary treatment In many US cities, sanitary sewers are connected to storm sewers. Heavy storms can overload the system, causing by- pass dumping of raw sewage and toxic runoff directly into watercourses
Unusual Pollutants are Now Being Detected in Surface Waters
Clean Water Act (1972) Goal was to return all U.S. surface waters to "fishable and swimmable" conditions. For Point Sources, Discharge Permits and Best Practicable Control Technology are required. Set zero discharge for 126 priority toxic pollutants. Areas of Contention Draining or Filling of Wetlands Many consider this taking of private land. Un-funded Mandates State or local governments must spend monies not repaid by Congress. WATER LEGISLATION
Water Remediation Containment methods confine liquid wastes in place, or cap surface with impermeable layer to divert water away from the site Extraction techniques used to pump out polluted water for treatment. oxidation, reduction, neutralization, or precipitation Living organisms used to effectively to break down polluted waters
FISH CONSUMPTION ADVISORIES: Locations and Contaminants Water Body Location Primary Contaminant Beaver Creek Albion Dieldrin Big Nemaha River Preston PCBs, Dieldrin *Czecchland Lake Prauge Mercury *Box Butte Reservoir Hemingford Mercury Carter Lake Omaha PCBs Elkhorn River Waterloo & Norfolk PCBs, Dieldrin Jeffrey Reservoir Brady PCBs Lake McConaughy Ogallala PCBs Lake Ogallala Ogallala PCBs, Dieldrin *Liberty Cove Lake Lawrence Mercury *Little Blue River Steele City Mercury Loup River Canal Genoa PCBs *Merritt Reservoir Valentine Mercury Midway Canyon Reservoir Cozad PCBs Missouri River Omaha & Plattsmouth PCBs, Dieldrin Missouri River Rulo Dieldrin *Oliver Reservoir Kimball Mercury Papillion Creek Bellevue PCBs, Dieldrin West Papillion Creek Ralston PCBs, Dieldrin Platte River North Bend to Missouri River PCBs, Dieldrin Salt Creek Lincoln to Platte River PCBs, Dieldrin *Skyview Lake Norfolk Mercury South Platte River Paxton PCBs Sutherland Outlet Canal Sutherland PCBs Sutherlan Reservoir Sutherland PCBs *Wehrspann Lake Millard Mercury West Fork, Big Blue River Dorchester Dieldrin *Zorinsky Lake Omaha Mercury * No cancer risk level involved. Mercury advisory is for pregnant or nursing women, infants and children under 15.
Carcinogenic Water Pollutants: 1. PCBs = polychlorinated biphenyl compounds marketed in the U.S. since 1929 Before 1971, they were used as plastisizers, heat transfer fluids, lubricants and wax extenders. Since 1971 PCBs have been limited to use in closed electrical systems (capacitors and transformers). The production of PCBs was discontinued in the U.S. in 1977, and their importation was greatly reduced in 1979 and completely stopped in 1982. Before 1979 the disposal of PCB compounds was not subject to federal regulation. Of the approximately 1.25 billion pounds purchased by U.S. industry, about 60% are still in use in capacitors, 36 percent are in landfills of dumps and about 4 percent had been destroyed by incineration or degraded by the environment.
Carcinogenic Water Pollutants: 2. Dieldrin = pesticide carcinogen Dieldrin was once widely applied to corn fields as a pest control agent, and it has been used to treat wood products for termite protection. The legal use of dieldrin in the U.S. was halted in 1974, except for its use as a means of subteranean termite control. In 1985 importation of dieldrin ceased, and in 1987 its registration was cancelled. Dieldrin remains in the environment as it is extremely persistent. This carcinogen is believed to emanate from both agriculture and urban runoff.
Carcinogenic Water Pollutants: 3. Mercury (organic form) carcinogen Mercury occurs naturally in the earth's soil, but is also present in the atmosphere from natural and man-induced sources. The primary industrial uses of mercury are in the manufacture of batteries, vapor discharge lamps, rectifiers, fluorescent bulbs, switches thermometers, and industrial control instruments. The products usually end up in landfills or incinerators. Mercury also has been used as a slimacide in the pulp and paper industry, as an antifouling and mildew-proofing agent in paints and as an antifungal seed dressing. Of the existing sources of mercury, it is widely accepted that atmospheric deposition of both natural and man-induced mercury is the major contributor both in our state and nation-wide. Cycling of mercury in the environment is facilitated by the volatile nature of its metallic form and by bacterial transformation of metallic and inorganic forms to stable mercury compounds, particularly in bottom sediments. It is the stable or organic mercury (methyl-mercury) that is detected in fish tissue and is harmful to humans.