3Ocean CurrentsNASA Visualization of Ocean Currents3
4The Hydrologic CycleThe hydrologic cycle. Most exchange occurs with evaporation from oceans and precipitation back to oceans. About one-tenth of water evaporated from oceans falls over land, is recycled through terrestrial systems, and eventually drains back to oceans in rivers.4
5The Hydrologic Cycle Constantly Redistributes Water Water cycles through environmentDescribe cycle:evaporation from moist surfaces/waterprecipitationrun-off (rivers/lakes); soil percolation (ground water)through living organismssolar energy drives the hydrologic cyclewater and sunlight are unevenly distributed around the globe, thus water resources are very unevenThe water we use cycles endlessly through the environment. The total amount of water on our planet is immense—more than 1,404 million km3 (370 billion billion gal) (table 11.1). This water evaporates from moist surfaces, falls as rain or snow, passes through living organisms, and returns to the ocean in a process known as the hydrologic cycle (see fig. 2.17). Every year, about 500,000 km3, or a layer 1.4 m thick, evaporates from the oceans. More than 90 percent of that moisture falls back on the ocean. The 47,000 km3 carried onshore joins some 72,000 km3 evaporated from lakes, rivers, soil, and plants to become our annual, renewable supply of fresh water. Plants play a major role in the hydrologic cycle, absorbing groundwater and pumping it into the atmosphere by transpiration (transport plus evaporation). In tropical forests, as much as 75 percent of annual precipitation is returned to the atmosphere by plants.Solar energy drives the hydrologic cycle by evaporating surface water, which becomes rain and snow. Because water and sunlight are unevenly distributed around the globe, water resources are very uneven. At Iquique in the Chilean desert, for instance, no rain has fallen in recorded history. At the other end of the scale, 26.5 m (86.8 ft) of rain was recorded in 1860 in Cherrapunji in India. Figure 11.2 shows current patterns of precipitation around the world, but climate change is altering that map. Cherrapunji, for example, only receives about one-third as much rain today as it did a century ago.5
6Mean Annual Precipitation The distribution of precipitation in different parts of the earth is certainly not even. Lack of precipitation, either regularly or seasonally, is the source of enormous human suffering. The amount of precipitation a particular area receives largely dictates the nature of vegetation and animals there. Such human suffering is prevalent in northern Africa where this map shows that less than 25 cm (10 inches) of rain falls per year.
7Water in the Worldwater covers 71% of earth’s surface
8Unique Properties of Water H-+due to molecular structurea polar molecule - excellent solventhydrogen bonding-+between water moleculesOHcohesiontensile strengthOH-+OH-+between water and other moleculesadhesioncapillarity - from cohesion and adhesion
11Case Study: Ch 11, When will Lake Mead go dry? Reasons for dams?flood controlelectricity generationwater sourcerecreation
12Case Study: Ch 11, When will Lake Mead go dry? 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)
13When will Lake Mead go dry? Case Study:When will Lake Mead go dry?The Colorado River is the lifeblood of the American Southwest. More than 30 million people and a $1.2 trillion regional economy in cities, such as Los Angeles, Phoenix, Las Vegas, and Denver, depend on its water. But the sustainability of this essential resource is in doubt. Drought, climate change, and rapid urban growth are creating worries about the future of the entire watershed. In 2008, Tim Barnett and David Pierce from the Scripts Institute in California published a provocative article suggesting that both Lake Mead and Lake Powell could reach levels within a decade or so at which neither would be able to either produce power or provide water for urban or agricultural use if no changes are made in current water allocations. The roots of this problem can be traced to the Colorado Compact of 1922, which allocated water rights for the seven states that adjoin the river. The previous decade had been the wettest in more than a thousand years. The estimated annual river flow of 18 million acre-feet (22 billion m3) negotiators though they could allocate was about 20 percent higher than the 20th century average.As cities have grown, however, and agriculture has expanded over the past century, competing claims for water have repeatedly caused tensions and disputes. climate change is expected to decrease river flows by 10 to 30 percent over the next 50 years. There may be only half as much water in the river in a few decades as negotiators once thought they had to distribute between the states. Since the year 2000, water level in Lake Mead in Nevada has been dropping about 12 feet (3.6 m) per year. Estimates are that without changes in current management plans, there’s a 50 percent chance minimum power pool levels in both Lakes Mead and Powell will be reached by 2017 and that there’s an equal chance that live storage in both lakes will be gone by about Already, we’re at or beyond the sustainable limits of the river. Currently, Lake Mead is only 43 percent full and Lake Powell holds 58 percent of its maximum volume. The shores of both lakes now display a wide "bath-tub ring" of deposited minerals left by the receding water.The American Southwest isn’t alone in facing this problem. The United Nations warns that water supplies are likely to become one of the most pressing environmental issues of the twenty-first century. By 2025, two-thirds of all humans could be living in places where water resources are inadequate.11-1313
14The Colorado River System 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, 201411-14
15Unique Properties of Water 1. liquid over wide range of temperatures due to cohesionboiling = 100°C (212°F)freezing = 0°C (32°F)2. high heat capacity (slowly changes temperature)stores heat well and can resists temperatures changescoastal areas have less temperature fluctuations than continental areasmoderates earth temperature3. requires much energy to evaporateskin furnishes heat and thus cools body
16Unique Properties of Water 4. great solvent (of polar compounds)polarity of water molecule keeps ions apartsalt (NaCl) ionizes in water
17Unique Properties of Water 5. surface tension and high wetting abilitycohesion and adhesion cause water to rise in plantsas water evaporates from the leaf surface,a column of wateris pulled upward from the soil water
18Unique Properties of Water 6. Expands when freezesice floats (insulates)7. Density increases as temperature decreases: most dense at 4°Cbodies of water (lakes and streams) remain liquid in winterturnover can occur in lakes in spring and fall
19Surface Waterwater that remains on earth’s surface as a result of precipitationwater in streams, lakes, wetlands, reservoirswatershedland region draining into a body of waterStagecoach Lakein lab we determined that lake’s watershedImpact of Rachel Carson’s Silent Spring
20Biological Amplificaiton Rachel Carson, Silent Spring10,000,000Xincrease in concentration
21Biomagnification cont’d Clear Lake, California (90 mi N San Francisco)copious numbers of gnats (not a mosquito)DDD (DDT relative) applied to lake1 part DDD : 70,000,000 parts water1/70 parts per millioncontrol repeated (now not as affective)1 part DDD : 50,000,000 parts water1/50 parts per million1955 Western Grebes starting to dierd wave of DDD applicationmore Western Grebes die; analysis of bird tissue:1600 parts DDD per million112,000 X increase in concentration
23Ground Waterwater that percolates downward through spaces in soil and rockzone of aerationupper soil layers that hold both air and waterzone of saturationregion of rock and soil that always maintains water in the spaceswater table begins at the zone of saturationaquiferwater-saturated layers of rock, sand, gravel through which groundwater flowsrelatively impermeable layers (rock & clay) keep water contained in aquiferrecharge area - land area that has water percolating downward into the aquifer
25Groundwater ProblemsTwo kinds of problems reduce groundwater’s utility:Discharge problemsGroundwater pollutionWithdrawal problemsDepletionLand subsidenceSalt water intrusionGroundwater 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.
31Ogallala Aquifer world’s largest know aquifer irrigation increases yields 2X to 3Xcentral pivot irrigation removes much water from the aquiferessentially nonrenewable (slow recharge rate)pumped 8-10X times faster than recharge rateexpect 25% reduction by 2020What are solutions?
34Groundwater Pollution Pollution of ground water is a serious water pollution issue that is largely out of sight. Pollution that seeps into the soil is gone as far as the people that created it are concerned; however, if it moves through that soil it can eventually contaminate groundwater. This polluted groundwater might be the source of drinking, industrial, or irrigation water.This figure shows the many potential sources of groundwater pollution. Note that the source of groundwater pollution, like other types of water pollution, is not necessarily in same place as the source of the polluted water. This is because the water moves laterally underground just as it does above ground.There is a very interesting recycling technique that millions of people in the U.S. practice. When a home relies on a well for its drinking water, it may also rely on an on-site sewage treatment of wastewater. This treated water is likely to be unknowingly recycled. Basically, water used in the home is introduced into the field adjacent to the home. This wastewater leaches through the soil and reaches the water table; then, the water is pumped through the home's well and reutilized by the people living in the home. Protection of ground water quality in Washington State from pollution is one of the state's highest priorities environmentally. Washington State has a policy of no net degradation of groundwater within the state.
35Water Quality TodayThis figure shows the percent of water quality impaired U.S. rivers in 1998 (U.S. EPA). It's important to notice that in some cases the percentages seem more a function of political boundaries then they are likely of reality, as this information is reported by states voluntarily. According to this data, Washington State is among the least polluted states in the United States. The State of Mississippi is by far the most polluted. It is a known fact that Washington State has suppressed the release of information on mercury contamination in the upper reaches of the Columbia River. Also, there are different standards by which states determine whether water is impaired in quality; however, it's obvious from this figure that water quality impairment is a serious issue in U.S. rivers.
36Pollution of Water Sources turn to neighbor and think of as many kinds of water pollution as possibleI’ll give you a short time to do this (minute or less)The group with the most, of course, wins
37Classes of Water Pollution 1. disease-causing agents (pathogens)bacteria (causing dysentery, enteritis)coliform bacteria (Escherischia coli = E. coli)normally live in intestinal tract of animalsindicators of fecal contamination if present in water0 bacteria/100ml water for drinking - WHO recommendation200 bacteria/100ml water for swimming - EPA recommendationvirusesinfectious hepatitisparasitesprotozoans (Giardia)worms (Schistosomiasis)Schistosomiasis occurrenceGiardia
38Classes of Water Pollution 2. Oxygen-demanding wasteswastes that decompose (organic) by oxygen requiring (aerobic) bacteriathe bacteria thus reduce DO in waterthis impacts all aquatic life - food chain (web)
39Classes of Water Pollution 2. Oxygen-demanding wastesBiological Oxygen Demand is the amount of oxygen required for microbial metabolism of organic compounds in waterhigh organic compounds increases BOD, leading to low quality watermicroorganisms feed on organic compounds in waterrestricts biodiversity in waterfeeding depletes oxygen in waterlarger organisms with gills have inadequate oxygen to breathmore organic compounds = greater feedingreduces oxygen in water greatly
40Classes of Water Pollution 3. water-soluble inorganic chemicalsacids, salts, compounds of toxic metals (mercury & lead)
41Classes of Water Pollution 4. Inorganic plant nutrientswater-soluble nitrates, phosphatesfrom where do these originate?
42Classes of Water Pollution 5. organic chemicalsoil, gasoline, plastics, pesticides, cleaning solvents, detergentsJan 9, 2014: Elk River (Charleston, WV)MCHM (4-methylcyclohexanemethanol), a chemical foam used to wash coal to reduce pollution; 7500 galupstream from drinking water intake and distribution centerPipeland 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)
43Classes of Water Pollution 6. sediment or suspended mattersoil erosion7. water-soluble radioactive isotopes8. thermal pollutioncooling of industrial and power plantscoal, nuclear & oil fired electric plants create steam to drive turbines
44Classes of Water Pollution 9. genetic pollutionintroduction of non-native speciesWater 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.
45Sewage Treatment Rationale Natural Processes More than 500 pathogenic bacteria, viruses, and parasites can travel from human or animal excrement through water.Natural ProcessesIn 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 MethodNatural water purificationEffluent can be used to irrigate crops or raise fish for human consumption.The rationale for continuing to improve on sewage treatment procedures and number of facilities is unquestionable. If for no other reason, the large improvement in water quality has resulted in a massive drop in mortality rates in developed countries during the 20th century. Many less developed areas, however, cannot afford or operate high technological water purifying facilities. In such areas, natural systems might be used to clean water. In fact, at low population densities, natural processes quickly eliminate wastes.As water infiltrates soil and moves through wetlands, it is also purified. Recently, artificial wetlands have been developed as an inexpensive means of purifying water. Similarly, forest soils clean water of organic compounds and pathogens. Wetlands, in particular, have become a partial solution to cleaning water for areas where there is currently not enough money or know-how to develop sewage treatment facilities.
46Lincoln 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 facilitiesTheresa Street Facility27th & Cornhusker20 million gallons of water dailyNortheast Facility5 million gallons of water dailyCombined this would fill Holmes Lake in 3.5 days
48Municipal Sewage Treatment 1. Primary Treatment - Physical separation of large solids from the waste streamscreening, pumping, grit removalget the big stuff outmaterial collected hauled to landfillprimary clarificationremoves settleable solidsremoves floatable materials like grease2-4 hrsprimary clarifier
49Municipal Sewage Treatment 2. Secondary Treatment - Biological degradation of dissolved organic compoundsBiological TreatmentAeration basinremoves pollutants with bacteria and protozoansmust be aerated8 hrsSecondary clarificationseparates treated wastewater from microorganism (from aeration basin)Disinfectionchlorination or UV light
50Municipal Sewage Treatment Anaerobic Digesters2. Solids processing - Biological degradation of dissolved organic compoundssolids digestionanaerobic digesters to stabilize organic solidsproduce methane gas (CH4) which can power turbine to generate electricity18-20 dayssolids dewateringremoves excess watersolids (organ rich material)Belt Filter Press Dewatering
51Municipal Sewage Treatment Subsurface Biosolids Injection2. Solids processing - Biological degradation of dissolved organic compoundsland applicationsoil amendment and fertilizeralternatively dewatering is replaced by collecting liquid and using it as fertilizer on city owned land
52Municipal Sewage Treatment 3. Tertiary Treatment - Removal of plant nutrients (nitrates and phosphates) from secondary effluent.Chemicals, or natural wetlandsLincoln does not have tertiary treatmentIn 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
53Unusual Pollutants are Now Being Detected in Surface Waters
54WATER LEGISLATION Clean Water Act (1972) Areas of Contention 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 ContentionDraining or Filling of WetlandsMany consider this taking of private land.Un-funded MandatesState or local governments must spend monies not repaid by Congress.
55Water Remediation Containment methods Extraction techniques confine liquid wastes in place, or cap surface with impermeable layer to divert water away from the siteExtraction techniquesused to pump out polluted water for treatment.oxidation, reduction, neutralization, or precipitationLiving organismsused to effectively to break down polluted waters
56FISH CONSUMPTION ADVISORIES: Locations and Contaminants Water Body Location Primary ContaminantBeaver Creek Albion DieldrinBig Nemaha River Preston PCBs, Dieldrin*Czecchland Lake Prauge Mercury*Box Butte Reservoir Hemingford MercuryCarter Lake Omaha PCBsElkhorn River Waterloo & Norfolk PCBs, DieldrinJeffrey Reservoir Brady PCBsLake McConaughy Ogallala PCBsLake Ogallala Ogallala PCBs, Dieldrin*Liberty Cove Lake Lawrence Mercury*Little Blue River Steele City MercuryLoup River Canal Genoa PCBs*Merritt Reservoir Valentine MercuryMidway Canyon Reservoir Cozad PCBsMissouri River Omaha & Plattsmouth PCBs, DieldrinMissouri River Rulo Dieldrin*Oliver Reservoir Kimball MercuryPapillion Creek Bellevue PCBs, DieldrinWest Papillion Creek Ralston PCBs, DieldrinPlatte River North Bend to Missouri River PCBs, DieldrinSalt Creek Lincoln to Platte River PCBs, Dieldrin*Skyview Lake Norfolk MercurySouth Platte River Paxton PCBsSutherland Outlet Canal Sutherland PCBsSutherlan Reservoir Sutherland PCBs*Wehrspann Lake Millard MercuryWest 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.
57Carcinogenic Water Pollutants: 1. PCBs = polychlorinated biphenyl compoundsmarketed in the U.S. since 1929Before 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.
58Carcinogenic Water Pollutants: 2. Dieldrin = pesticidecarcinogenDieldrin 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.
59Carcinogenic Water Pollutants: 3. Mercury (organic form) carcinogenMercury 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.