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chapter 10 freshwater resources and water pollution water is another one of those natural resources that we oftentimes don't really think of that much about in our daily lives I mean use it everyday life wouldn't be possible without water but generally speaking especially in this country we always are able to turn the water faucet on and get water out to do whatever we need to do with it when we have years like we're having now in California and really the last three years where we've been in a drought situation then we start really thinking and worrying about it water allocations for agriculture impacts to wildlife lakes that are built behind dams for recreation that aren't full enough how does that impact the economy all of the businesses that depend on the the recreation that comes to an area so again I think we're all pretty much in agreement that water is a very important part of our earth but again we oftentimes unfortunately take it for granted all living things on this planet contain water and humans are about seventy percent water and again every day every one of us depends on water for everything from from drinking it and cooking to washing dishes to taking showers agriculture for the food we depend on transportation and manufacturing mining again basically it involves everything that we depend on to sort of compound this challenge we look at the earth and water is plentiful on the earth the problem is however that about ninety-seven percent of it is salty water that's in our oceans less than three percent of the water on this planet is actually usable by humans to drink and do all the other things that I just listed and then you add to that the fact that water is not equally available across the globe it's very much unevenly distributed I read something at some point in the past that indicated if all of the precipitation that hit the earth were equally distributed across the dry land everybody would have about three feet of water and that's about the average rainfall that reading gets but again there are some places on the planet that get no rainfall in a given year and other places they get more than 100 inches so again it's it's unevenly distributed which makes it a challenge for those who live in areas where water isn't plentiful it's estimated that by the year twenty 25 more than one-third of humans will live in areas that do not have an adequate freshwater supply either for drinking or for producing food and also remember of that roughly three percent of the water on the surface of the earth is freshwater only a very small percentage of it is not tied up in ice and glaciers so of that hundred percent of all the water on this planet only about point O three percent and then about 0.5% more of that is typically available for us to actually access and utilize not really going to go into a ton of chemistry but water is a unique molecule that exists on this earth because it exists in three different forms a gas liquid and a solid each individual molecule of water contains one hydrogen and excuse me one oxygen and two hydrogen atoms that are held together by bonds and water molecules are considered be polar meaning they have a positive charge on one end the hydrogen end and a negative charge on the other end so they can attract to each other multiple water molecules can easily attach to each other and this is done by hydrogen bonds so each end of every water molecules attached to the opposite end of an adjacent water molecule basically forming a hydrogen bond between multiple molecules of hydrogen and again it's these covalent bonds or hydrogen bonds I mean that that are responsible for the fact that water has a high freezing point and it has a high melting point it has a high boiling point it can hold a lot of heat and it can actually work as a solvent meaning it can dissolve other chemicals so again it's all of these properties that that have contributed to how important water is for life on this planet we talked about the biogeochemical cycles and of course they're all important for life on this planet but again we'll revisit the hydrologic cycle because of how important water is to everything so again basically we're looking at water that circulates throughout the environment from the atmosphere where it eventually enough water molecules kind of bond together that they get too heavy to stay in the atmosphere they fall back to the earth they either land snow or rain the rain either flows across the surface of the earth into a nearby water system or and i should say some of that water also percolates or infiltrates into the soil where it accumulates in the groundwater however ultimately that groundwater is still going to be moving underground and work its way into nearby lakes rivers streams and then ultimately the ocean and then all of the land mass that that holds water whether it's lakes or streams rivers oceans are going to be subject to the evaporation process or that water because of the sun's energy and movement of the water causes those molecules to enter into the atmosphere where the process starts all over again and then of course in addition to that you have the evapotranspiration which is basically the equivalent to a plant sweating giving off moisture through the pores and its leaves when the temperature is hot or dry and basically this whole process provides a balance of water that's in the atmosphere on the land and in the ocean and is what recharges or renews our freshwater supply so we as humans for all the needs we have for water depend on surface water which is the precipitation that remains on the surface of the land that doesn't get into the soil and it gets there by runoff through drainage basins and watersheds into again rivers streams lakes and when we then build dams in systems then we're basically increasing the ability to store that runoff as surface water but we also very much depend on groundwater supplies which are the freshwater systems that create these underground aquifers or underground reservoirs of water this is replenished by again water infiltrating through the soil profile down to the water table it can take relatively short amounts of time to replenish these groundwater tables or it can take hundreds to thousands of years for those groundwater tables to be formed those underwater underground aquifers so a lot of times especially when we're not using them wisely those aquifers can be considered a non-renewable resource because again if we're drawing water out of them quicker then they can be replenished naturally then it's like any other non-renewable resource like fossil fuel again just another diagram kind of showing examples of how the the water table might look the confined aquifer which is a water that's contained within soil that's trapped between two impermeable layers and basically the bottom line to really take from this is a lot of people have this notion of the water that's underground is is there in some sort of underground lake or underground river and in reality the the aquifers are really just water that's in soil that's in between all the little particles of soil so while there are some larger sort of underground caverns the majority of the water that we pump out of the ground for our use are in aquifers that are again just water that's in between the soil particles so we can have water problems where we have too little water which is kind of what we're really worried about now in California way under the average amount of rainfall that we have typically gotten so snowpack in the mountains that feeds the streams is going to be really low the water that's stored in the reservoirs that humans have built is way way down and so that can potentially have a huge impact on the environment much less all of the other demands that humans have for so again that's typically what we worry about in this country when we don't have enough water but there's certainly our problems when you have too much water think about floods that happen in the spring or floods that happen from hurricanes where areas are flooded with water inundated with feet or tens of feet of water which can certainly do a lot of damage and really be a disease issue spreading diseases and so that happens in this country obviously but really the the bigger problem for the bulk of the people on planet those especially in less developed countries is having water that is too poor of equality to either drink safely or basically you know just isn't clean enough to keep them healthy they have to rely on water that's in rivers they don't have the money or the technology to pump it out of the ground for everybody that lives out in the countryside so they really depend on that water that's in the nearby river systems and again that water is not purified or cleaned in any way for the people use it so animals have been in the water pollutants from other places upriver and people are forced to drink it because they need water but again it's it's not cleaned in any way so a lot of the disease issues are direct result of drinking poor quality water so again too much water basically comes in the form of flooding when a rivers system can't keep up with the amount of runoff that's occurring in it within its normal channels now nature certainly has a plan for this before we came along and mess things up there are flood areas floodplains that naturally form areas where rivers then have a place to lose all their excess overflow and they also carry with the flood waters a lot of soil particles from higher up the river which provides for extra nutrients for that soil but we as humans have have straightened rivers we've channelized them we've removed a lot of the vegetation along the rivers for building and so we've really affected the rivers ability to buffer those flood periods so anytime you replace plant cover native cover and in normal meandering rivers that wind around with paved areas and areas that have no vegetation you're going to dramatically again increase the risk of having more major floods bathing is really one of the largest problems that we have with respect to a lot of things it affects the climate of cities especially but more pavements you have the more of that rainfall that hits the ground runs off rather than it percolating and recharging the groundwater the image on the Left shows kind of on average what happens when you have precipitation hit the surface of the earth about forty percent of it is absorbed or intercepted by vegetation and then it either evaporates back off the ground or it's transpired back to the atmosphere by the plants about ten percent of it would run off which means it's going to head for the nearest stream lake river ocean and then about fifty percent of it in a pre urban sort of setting where again we don't have a bunch of pavement on the ground would make it into the groundwater now you compare that to a typical urban setting where less of the water evaporates and transpires back to the atmosphere because you don't have as much plant material a whole lot more of it about forty three percent of it runs off through storm sewer systems from roads from buildings from parking lots and then you only have about one third of that water actually making it down to the ground water to recharge it so again dropping from fifty percent to about thirty percent groundwater is a substantial change and then of course you tie into that the fact that the people in those urban areas are drawing a lot of water out of the ground for all their uses so these land development changes with us being on the planet and paving and building have dramatically changed the natural flow of water so therefore upsetting the hydrologic cycle so too little water is always an issue in very dry types landscapes those desert biomes that we spoke about earlier in the class plants that live in those climates and the animals that live in those types of habitats basically have adapted to it they survive even with a very limited amount of precipitation the plants have adaptations like loss of leaves so cacti generally are green they photosynthesize but they don't have all those little leaves that can dry out quickly and die in a very hot dry climate and a lot of the animals have adapted to that climate as well by getting the moisture they need for their survival from the food they eat a lot of desert animals don't even drink water even if it were available which again normally it isn't then we also have semi-arid lands they get more precipitation than deserts desert by definition is such because it gets less than 10 inches of rainfall a year so semi-arid lands get more rainfall than that but they also have extended periods of dry conditions or drought that again the native plants have to adapt to it's interesting I don't know if any of you knew this but if you look at the average rainfall that we get down in the San Joaquin Valley so the valley south of Sacramento down to around Bakersfield that whole area very rich in agriculture lots of tree fruits lots of vegetables on the on the west side that area gets typically about eight inches of rain a year so it's classified technically as a desert boy reason that we can grow as much food as we do is number one because it's really good soil all the mountains around the valley you rode down into Valley and then we used to have an inland ocean here so a lot of time that went by that was able to really build really good soil but then of course that doesn't matter is if you don't have water and again fortunately in normal years we've got all the mountains around the valley in snow pack and the reservoirs and the rivers that feed the valley with the water it needs this year they're already talking about a zero allocation from the surface water supplies for the farmers and ranchers 0% of their normal water so they're going to have to try and depend on groundwater this year more than they ever probably do and again doesn't mean that the groundwater supplies are endless either so it's going to be a really interesting year again we know that basically farmers in many areas use irrigation to increase the productivity of their arid and semi-arid lands again without irrigation in the valley and in most of the areas of California we could not grow food so the compound problems like we're having now with the drought you look at the ever-increasing amount of land that's being irrigated for crops 71 percent of the water that we use in the world is used for irrigation again that's this country and that's all the other countries in the world on average 71 percent of our water supply goes to grow food and depending on the type of irrigation it can be something pretty efficient like drip irrigation or it can be something pretty inefficient like flooding or using those overhead sprinklers where a lot of that water is actually lost back to the atmosphere before it ever touches the ground so we'll talk about some of the conservation issues here shortly so looking at aquifer depletion is always something that we worry about in the dry and arid parts of the world when we have more groundwater being removed then it can be recharged by precipitation or snowmelt we are in a situation where we're depleting our aquifer so the lower the water table gets the less accessible that water becomes and less water there is the water table is basically if you go down below the surface of the soil to where the soil is saturated with water that's the level of the water table as we pump more and more water from our aquifers all of the spaces between the soil particles that were once filled with water become empty just oxygen air space between those soil particles when there was water between those soil particles they kind of held their shape but when you remove that water they weaken and they can collapse or what's called subsidence and you can see all kinds of examples around the valley of california where in in areas where the aquifers have been depleted you have large areas of land that have kind of sunk down dropped i also mentioned earlier about saltwater intrusion with rising ocean levels the saltwater will push farther up rivers up freshwater rivers making less of that fresh water available to us but again you also have that salt water pushing und
rground into the aquifers making those aquifers saline and therefore again no longer usable by us for the things we need fresh water for so there are a lot of water problems and unfortunately we face all of these in California your book uses an example of the Ogallala Aquifer which is the largest groundwater deposit in the entire world you can see that it spans from South Dakota heavily through Nebraska Colorado Kansas Oklahoma New Mexico and down in through the panhandle of Texas this also if you remember is the breadbasket of our country this is agricultural land a lot of it is where we grow a lot of the staple foods like corn and wheat in this aquifer even though it's very deep in some places excess of 300 meters which is a thousand feet there are so much demands on this water from agriculture that it's being removed 40 times faster than its being replenished by nature the water table has dropped upwards of 100 feet in some areas since we've been paying attention to these issues again the time to worry about that problem is now not when the water gets is less available so there has been a lot of water conservation being done doing much more efficient irrigation practices again getting away from overhead sprinklers that are among the most wasteful to far more manageable systems like drip line and micro irrigation and certainly those kinds of practices will continue to slow the rate of aquifer depletion but we're still taking water out quicker than it can be replenished so that's not ultimately a sustainable process I don't recall if I placed it in here somewhere else but there's an aquifer in the Edwards Plateau which is kind of in the san antonio austin area kind of in the middle or lower right part of texas there's a big aquifer there called the Edwards aquaphor in the Edwards Plateau area of Texas and for decades now they've actually been creating recharge zones areas where they forbid any any new developments no new roads no paving no parking locks none of that to maintain large areas of natural vegetation that facilitate the most amount of water getting into the aquifer of course again you've got two fairly large cities in that area that demand a lot of water so they've been thinking ahead and being proactive now for quite a while to try and make sure they don't deplete that very important aquifer so we overdraw our aquifers and that's not sustainable we also have a tendency to overdraw our surface waters when we do that the wetlands that are so important to cleaning and keeping the water in our environment clean dry up the more we use the fresh water as it flows down the rivers the more that those estuaries become saltier because again if there's less freshwater pushing out towards the ocean it means there's more salt water pushing up the freshwater and because of how important the estuaries are to so much marine life that we depend on there's there's a lot of concern that as these estuaries become saltier because of the balance in balance with freshwater that a lot of those species could start disappearing water shortages are not only an inconvenience they're they're serious economic issues as well as the ecological problems that can occur because of water shortages again before we were so populous pretty much water was the only use for water was the the environment now we demand water directly we demand a huge amount of water to grow the food we need and it becomes harder and harder to balance our needs with needs of the native plants and animals and that just becomes a bigger and bigger and bigger problem there are lots of water supply and quality problems in the United States but again often times less that right in our backyard we just don't ever think about the fact that we could not have water in an area throughout the western us all we need are drier than average years and we have water problems if you're on city water you may not notice a whole lot there may be warnings like there will be if and there have been already this year about everybody being more conservation minded and not washing your car every other day not hosing down your driveway to get the grass off it you know watch how much you're irrigating your landscape all those little things that we can all do are going to be more and more important and again it should be that we want to do that not when there's a problem that we suddenly got fixed but so that there are no problems we should be thinking conservation of water we live up in in a small little town outside reading and we have a well a couple years ago our well kind of started slowing down and not running as well we had a lot of plants that were on irrigation it was all drip line so it was as good as it could be we started cutting back on watering some of the vegetation and things that survived we you know give a little water when we could but if they didn't survive then we just quit watering them we don't have a lawn appear that we have to water so right now especially this year we're more in the mode of just thinking about saving water for our necessities and not wasting it on other things taking quicker showers not flushing the toilet when you pee in it every time just little things that make a huge difference a lot of soil in the southwestern Valley of California has a sale anization problem where because of improper irrigation in the past it is allowed for the slow gradual accumulation of salt again you get a hot dry climate where there's a lot of evaporation because again the humidity is low and then you heavily irrigate areas there's always going to be salt and mineral deposits and so as so much of that moisture evaporates way it leaves behind the assault normally in an area where precipitation would occur it would carry those salts away and kind of keep flushing the soil out but in these very arid and semi-arid areas that doesn't have a lot of precipitation remember that part of the valley down there might get eight inches of rain a year those salts remain in the soil and eventually they accumulate to the point where they're too toxic for plants to grow in and then basically that that soil can no longer be used to grow any crops there have been a lot of things going on with developing salt resistant plants but there were areas down there that I haven't seen utilized and then the entire time I've lived in California you drive by those areas you see kind of a gray looking soil and that's usually a pretty good indicator it's got some saline issues again because of the uneven distribution water it's pretty typical around the world that not all humans are located where there's water and then as population pressures continue to grow and the the demand on the land continues to increase we continue to reduce the natural ability of the water to recharge itself then you add into that pollution from the industries that make the products we depend on pollution from agricultural activities which could just be run off of fertilizer and and so many other things that generate different types of pollutants you further reduce the availability of that fresh water because now it's been contaminated where it's no longer safe to drink or to use on our plants so because again this becomes a worldwide issue we have to continue to do a better job of cooperating with other countries that share watersheds you know us with Mexico or Canada to the north other countries in Europe that are more closely you know bordering each other and not take the attitude of you know i'm just going to pillage and plunder all the water i can get and don't really care about the neighbors that's a example even that we see just here in california sometimes people tapping into water systems taking water out of streams illegally that might otherwise flow through other people's land all those kinds of things are going to have to continue to become a priority and again again it's not just about becoming a priority today because we're in the middle the drought it's about becoming sustainable with our water use so that when there are droughts and we've already been conserving our resources we don't suddenly run out it's kind of the idea that you hear about that half Americans are more than half aware of the Americans and in the US are living paycheck to paycheck you get two thousand dollars a month and you spend two thousand dollars a month and then what happens if you get laid off or you get ill you basically have no reserve to draw on if you need to for a month or a year it's really the same exact example that we should be looking at with our resources water soil our air we should be thinking ahead of time trying to conserve it use it wisely put some in the bank if you will so that when we have these kinds of droughts we're having now that we've kind of been conserved conservation-minded maybe we even have to come back a little more than we did before but at least if we've been conserving all along instead of just well I better start today we're going to be better off so again it's all about reusing and recycling water improving the efficiency of our use of water all those things are very important part of sustainable use but of course when water is cheap which it really still is it encourages us to waste it because we aren't really accountable for it when gas hit five dollars a gallon a few years ago all of us were just freaked out and and you know I'm not going to take vacations I'm not going to you know do excess driving I'm a dolmen all my shopping in one day and plan my route and save all the gas and then when it drops down below four dollars a gallon after we get kind of used to the sticker shock we just pretty much have gone back to what we've always done before we thought about conserving the fuel and it's again it's the same with water especially with water I don't know how much you know an average water bill is but whatever you're paying for water it really isn't enough for what that resource really is worth and so again when things are cheap we don't think about saving them as long as we turn the tap then there's water coming out we feel like we're in pretty good shape again we have to kind of get over that attitude to be seen making conservation all the time even on those years when we get twice the amount of precipitation that's normal so the technology that we've used for a long time now to increase the amount of surface water that we can store our v8 building dams and reservoirs find a good location and build a dam the snowmelt or the rainfall feeds that system and fills it up above the dam and then in many cases those dams are also used to generate electricity so we also then not only have a year-round water supply in areas that might not otherwise have had a year-round water supply but we also got some relatively inexpensive energy we can generate the problem is back when we started building most of the big dams shasta dam up north the columbia river the dams along the Snake River all the dams along the Mississippi River we really again didn't fully understand the hydrologic cycle and all the negative impacts that dams and reservoirs have on fish populations for example in California now we've had it for probably 20 years a priority to have to manage these river systems and even get rid of some dams to benefit the salmon so they can get back up river and still spawn and not be not be subject to going extinct most of the major river systems in this country and in the world to a degree that could be damned have already been dammed so there's not a lot of opportunity for us to build more dams to store more water you probably have heard the the latest talk about shasta dam the idea of raising shasta dam so there's no other river system to dam but maybe we can raise shafts and allow for more water storage in the years when we get enough rainfall to fill it up obviously you know the shasta dam could be a hundred feet taller and it would still be at thirty percent of its capacity because we just haven't been getting the precipitation but what about in the really good years if we built it ten or twenty feet taller than it is now which I think that's somewhere in the range of what they're looking at 10 feet or 20 feet something like that then that provides a substantially greater volume of water that we could store and then again use in the years when we get in a frame fall to fill it but even though there's already a damn there there would be additional ecological problems cultural problems there'd be campgrounds that would have to go away that people have maybe been using and their families have been using their whole lives cultural Native American sites that would be underwater think about all the the houseboat places on shasta that would have to either move farther above the water line or in some cases there may not be enough dry land for them to even stay there so lots of economic lots of ecological and lots of cultural effects just to raise shasta dam so part of the solution comes from making more water available by you know creating reservoirs which again I've said that we've pretty much already done as much of that as we can so the solution really has to come from the other end using the water that we do have access to wisely again in other words conserving it continuing to develop better ways to irrigate our land and therefore reducing water waste not letting it run off letting all of that water that hits the ground percolate into the soil like it does when we use things like drip line reducing the amount of water that's wasted in industry water is is because of its heat capacity the ability for it to hold heat water is used a lot in industries just as a way to cool machinery water is consumed as well but a lot of water is just used to cool things and then it's dumped back into the environment much hotter which creates pollution so just finding ways to be more efficient with the water use and then reducing municipal water waste again this is where it really matters this is all 300 plus millen million of us in the United States and the thirty six or seven million of us in California each doing something to help if you look at kind of a typical household we use water in our bathrooms our sinks for brushing our teeth in the morning showers the toilet we use water in our kitchens for doing dishes for cooking for cleaning we use water to clean our clothes you do our laundry we use water to some degree for outside to water plants to irrigate our lawns to fill our our fish ponds outside to wash our cars all those things again it all involves breaking down these processes being as efficient as you can in California you really can't buy a water faucet that isn't the water saving device for quite a while now California has been ahead of the game on that a lot of people don't like the low flush toilets for a lot of reasons but we've been involved in that for quite a long time if you have a very old house let's say something that goes back to the 50s or maybe 60s and you still have the original toilet or the original fixtures they probably are not low flow and for a relatively small amount of money you can replace shower heads and fixtures that are much much more efficient big part of this though even if you whatever type of fixtures you have a lot of this is going to be really just changing your habits not leaving the faucet run while you're brushing your teeth or washing your face or shaving taking showers that are shorter get in clean up rinse off and then move on appliances like dishwashers have continually gotten more and more efficient and actually it's from what I've read it's generally more efficient to actually use the dishwasher to do dishes it uses less water it does use electricity obviously but if you avoid doing dishes during the peak times no you put them on to run ten o'clock at night or early in the morning you're not using as much energy or it's cheaper I should say and again if you use the dishwasher and you always wash a full load not a partial load it really is a more efficient use of your water when you have to replace your washing machine spend as much money as you can afford to get the most efficient washing machine you can they use far less water they spin more water out of the clothes so that when you put those in the dryer the dry
r doesn't have to work as hard to get your clothes dry and then again a big big waste of water is in the toilets on average we as a typical family in the United States use about 60 gallons of water per day and again the biggest use of that typically is in the toilets you think of a family of four and how many times while you're home during the day or at night that she use the toilet again simply not flushing everything every single time that's why there's a lid on the toilet if you don't want to see the bluish green water you can put the lid down and then again just making sure that as you need to replace things you just get the lowest flow toilet that you can afford so many of us waste water outside without even knowing it one of those things that really drives me crazy driving through town sprinkler sprinklers and people's lawns will be running in the middle of the day in the summer that is the absolute worst time of the day to use sprinklers because a large percentage of that water is just going to evaporate not even do the grass any good because how hot it is sprinklers should be set to run at say four o'clock in the morning you get less evaporation but then within a few hours the sun's up and so you don't get the mold or any of the diseases that might otherwise happen plus people that never check or adjust their sprinklers anytime you see water running off of the lawn and down the street and into the gutter you're using too much water again adjust the timer to run less and less and you know again for that matter think about even alternatives to landscaping using native plants and in garden beds that are mulched drip line instead of sprinklers all those things can make a huge difference but there's so much water that's wasted on improperly set irrigation systems for lawns and then of course again you know washing your car people that use their hoses to rinse or clean things off like their driveways too lazy to use a broom I guess I've been guilty that a few times in the past myself before I really thought about it and decided that wasn't a good thing to do but then really again there's there's so much other technology that's available that we just haven't incorporated yet if every house had a great water storage tank either underground or in the basement it would catch all the water that comes from basically everything except the waste that leaves the toilet so the water that runs out of the dishwasher or the sinks or the tub or the the clothes washing machine again that's not water that's drinkable for us but what can it be used for well it can fill the toilet up again to flush the toilet it can be used to irrigate your lawn and if we started incorporating that into all construction new home construction that we had grey water tanks it would get less and less expensive and if we had even the gutter system on our house attached to a storage tank so that in the rainy season all the rain that runs down our gutters could go into an underground storage tank we could fill that up over the course of a winter even easily in a place like reading and then depending on how big of a tank you have that could be used to again irrigate your lawn or do other things that you need to do with that water rather than you know tapping into other water supplies so lots and lots of things that we can and should be doing in our own homes to save water any physical or chemical change to water that makes it unhealthy for humans to drink or that can impact other living things is considered water pollution this could be examples of things like sewage could be disease-causing agents that are native you know natural or things that we dump into our water system just like soil particles in the air is air pollution sediment that gets into the water is a type of pollution as well and then again so many other substances chemicals compounds that get into our water supplies because of things we've done the other one that I briefly mentioned is thermal pollution water that's heated up as it's used in industry and then it's dumped back in the water much hotter that it was really really I removed from so just having much warmer water being dumped into a system is a type of pollution because it can affect the type of life in that area so again table 10.1 shows some of the examples of the types of pollutions I just listed where they come from a specific example and then the effects that these things can have on living things so for the purpose of a of a quiz probably good to know these items what they are where they come from what effects they caused so I'll go through each of these real quick quickly here for you sewage is basically waste water from drains or sewers that include human waste or other items that we use like soaps or detergents that can be again when they're in excess amounts can be a detriment to the environment human waste or animal waste can contain disease-causing agents that compose a health threat to public if it's not treated detergents and soaps the chemicals like phosphorus or phosphates that are in soaps and detergents are our fertilizer and so they can actually enrich an environment but not in a good way these kinds of chemicals being dumped into an environment can create this change in the balance of microorganisms because of this biochemical oxygen demand every living thing needs a certain amount of oxygen to survive whether it's a little microscopic thing living in a lake or whether it's a human when these chemicals like the phosphates and other fertilizers get into water systems and they decompose they basically affect the availability of lot of oxygen in the water and so then again some organisms that don't need as much oxygen can actually thrive things like algae but all the other living things that need oxygen there may not be enough so it really can cause an imbalance in the in the ecosystem so this look I basically summarizes what I was just talking about including showing how the oxygen concentration changes and relates to this killing off of things like fish that live in that water a couple other terms here that we need to go through Lakes just like land age over time they go through a process of change we called it succession on the land and it's basically the same process in water except we refer to it as eutrophication and basically it's going from being a young body of water to aging and being an older body of water when a lake starts out like like say Lake Tahoe it was scoured out by glaciers down to bare rock and then when the when the glaciers melted they filled in the lake with crystal-clear water because it was all rocky bottom so it was clean water no nutrients in that water and so it supported very small populations of living things if there were streams or rivers connected to these lakes or streams or rivers were created after these lakes were created and you could get fish that would migrate up river and get into these lakes they just didn't have a lot of food to eat because again you've got a rocky bottom very little vegetation very little nutrients to fuel the food chain so these types of bodies of water that are clear water lots of light can penetrate and very deep little algae growth low nutrients and then typically if fish live in these areas there were called cool water fish these are called oligotrophic which again we just kind of listed all characteristics so Lake Tahoe for example if you've ever been there you can see down 40 50 60 feet in some places although it's not as clear as it once was crater lake up to our north would be examples of illegal traffic lakes so that means again that they're relatively young Lakes Lake Tahoe's was probably created about 10,000 years ago when the glaciers retreated from the mountains 10,000 years one time humans but not not a very long time geologically so given time all lakes will age and they will you to phi which basically means that you have soil eroding into these lakes from the areas around them that soil contains nutrients so the bottoms of lakes go from being rocky to being more sandy and silty and clay so they're basically like the soil around the lakes that nutrient that gets in their causes more microscopic life to exist the more the microscopic life lives the the darker the water gifts just because those hal-g and all the other microscopic living things just take up space and then when that water gets darker you can't see down as far because it's got lots of stuff in it it holds heat better darker colors absorb more heat so the darker the water gets the warmer it tends to get and because you've got the soil eroding into the lake the lakes generally start getting shallower so a eutrophic lake then is a much older lake the water is cloudy or because of all the living things in it all the the soil particles as well the waters got a lot of nutrients in it and basically the fish species that live in these lakes are warm water species sometimes we think of many of these species is being kind of garbage fish like carp but basically a eutrophic lake is a much older lake now again that's that that's a natural process but humans have also caused artificial eutrophication again when we have run off of agricultural fertilizer fertilizer fertilizer it'll fertilize microscopic things in the water or it will fertilize the plants that we're trying to grow so by over fertilizing even our lawns if we over fertilize them and then over irrigate them those chemicals fertilizers flush into the water system and so by over nourishing an aquatic ecosystem we basically are speeding up the aging process and we end up with smaller lakes and ponds like the one on the left that are green that we call pea soup all of them algae and stuff that lives in there basically is demanding so much oxygen now that the other fish and things don't have enough to live in there so again just like succession is a natural process that we can speed up eutrophication is a natural process that we as humans can speed up when we look at water pollution there are basically two sources of water pollution those that we call point sources and those that we call non-point sources point sources are like this image there's a pollutant being dumped into the environment typically through a pipe and we could trace that pipe backwards to the factory that it came from or wherever it came from so point sources are easy to detect because again we can trace it directly from where it's going into the environment back to where it came from the ones that are really challenging are the nonpoint sources of pollution these are pollutants that get into a body of water over a large area not a specific single point of entry in other words you have rainfall the rain flows across the surface and it carries with it fertilizer or other pollutants that eventually may reach the groundwater or they'll reach the nearest flowing water system so again these non-point sources are accumulated over a large area and so it's not always possible to tell exactly where they're coming from groundwater pollution basically has rendered about half excuse me about half of our us water supply comes from groundwater so when those groundwater supplies get polluted there's basically nothing we can do to clean them if a river gets pollution in it or lake gets pollution in it there's at least the potential that we could you know treat it or stop the source of the pollution from occurring and then given time it'll fix itself especially when you get really nasty compounds organic compounds and really persistent chemicals that get into the groundwater from leakage or from factories that water becomes contaminated and basically then it is not usable cleanup is is almost never feasible for groundwater you might be able to pump it out of the ground and you may be able to partially treat it depending on exactly what's in it but there are some chemicals that are so nasty that there's just really no way to make those water supplies safe and drinkable again or if you could technically do it it is so expensive that it's generally not done unless there were no other alternative and there may not be alternatives for example in years like we have now I really hope I mean I'm a little worried about this but I also kind of hope that we take a serious look at our water policy in California and make some serious long-term changes to our policy for for a lot of things but again in here's like this we start freaking out and then we try and do things and then as soon as we get one good year we forget about it all we need to make changes that are going to be in place forever that that make us think about conserving water every day so this image just kind of gives you a sense of some of the ways that groundwater can be from the left side the pesticides like nitrates and phosphates that that are chemicals that we use to kill pests on crops or fertilized crops can seep into the groundwater they are toxic chemicals of course to to us we can have deep well injection of hazardous waste that were intentionally dumping down in the ground to get rid of it and then it can get into an aquifer we had a big a big change going on back in probably before a lot of you are on this planet but probably more than 20 years ago they changed the regulations on the underground gasoline storage tanks at gas stations then I remember there were a lot of small gas stations that went out of business because they couldn't afford to to change out the tanks for the kinds that were required by law and so that was another one of those economic hardships some small little stores you know country stores and things that had gas that just couldn't afford it had to go out of business or they just had to quit selling gas and in many cases gas was a huge part of their income but now we have a better system in place you know thicker requirements for the gasoline storage tanks septic tanks that that discharge chemicals into a system if you have your own well you have a septic tank and if you dump nasty stuff in down your drain or down your toilet a lot of the chemicals we use to clean we don't really think about how toxic they are but a lot of the cleaning products we use should never go down the sink discharges from sewers from landfills and again all the chemicals that get dumped in the environment through the process of manufacturing things so it's pretty simple how we improve our water supply we either remove the contaminants that get in there before we dump the water back to the environment or after we use that water we purify and reuse it there's there's really one technology that could solve our problems and deals with taking salt water and making it fresh water so we could drink it I believe we'll talk about that but cities basically have to provide a clean drinking water supply to the residents and they do that by municipal water treatment plants where the water is taken from wherever it's taken from behind a dam or a river or wherever and then it goes through a process to be treated and filtered and disinfected so that we can drink it then that water again if you're in a city the water you flush down the toilet or the water that goes down the sinks goes back to these water treatment plants in many cases anyway and then it's treated again so that it can be usable again by us for the same things I'm not going to go into a huge amount of detail here the book describes the actual process of treating sewage the primary secondary and tertiary treatment and there's an image in the book that shows that that you can look at there is one other thing to consider however the process of taking sewage and treating it and purifying the water still does create primary and secondary sludge the solids that were in that sewage so that's still always been an ongoing challenge of how to use that stuff for how to get rid of it in the past typically we would take it to a landfill that solid material would go into a landfill just like other solid waste but we've started getting a little more creative lately with better solutions building artificial wetlands to treat this water that's been reclaimed so that it filters through the system and eventually gets dumped back out into the rock that way we're using nature and the normal process is that wetlands fill to clean
that water before it filters back into the groundwater or whatever nearby water system it goes into and then along the way of course it's also providing habitat for wildlife they may not have that kind of habitat available to them in in around cities so like with a lot of things that we talk about in this class most effective way of controlling pollution is to minimize it even being created so there's legislation it's been in place since the Safe Drinking Water Act and the Clean Water Act in the 1970s that are very effective on point sources of pollution if you're a factory and you're discharging water out into a waterway it's pretty easy to regulate that because you can tell exactly where it's coming from but there's still a lot of work that needs to be done especially on those non-point sources of pollution again the safe drinking water act pretty much set uniform federal standards for drinking water that would guarantee that we have a safe drinking water supply the EPA ultimately determines the maximum levels of contaminants that are allowable going back to an earlier chapter how much of a chemical is safe basically and then having you know something around that level as being the maximum allowable amount it's not as great as it would be it's not feasible to have zero amount of chemicals and water there's just no feasible way for that to be the case but again we're trying to regulate it so that there are absolute maximums that are allowed based on that value of chemical being safe non-toxic are not harmful to humans and of course these acts have been mended over time as we've learned more or as new chemicals have been created for processes since the Clean Water Act in 77 our rivers and lakes and waterways have become better we've eliminated a lot of pollution from being dumped into our waterways we've achieved levels that are safe for fishing and swimming in many cases but there are still situations that we are worrying about in the future when I was growing up in Wisconsin in the 70s there was a limit on how much salmon we could eat out of Lake Michigan because of the levels of PCBs that is no longer an issue up there those chemicals have been more heavily regulated time has elapsed to allow those chemicals to work their way out of the environment but we've still got a lot of problem with things like lead mercury heavy metals that have been used for a long time in a lot of processes especially those heavy metals and things like PCBs they persist in the environment for a long time they bioaccumulate they magnify up the food chain and and could cause problems for decades and decades and decades after they're no longer produced so again it's really all about each of us doing a little bit of prevention so that collectively the effect is big enough to be noticeable not dumping stuff down toilets like medicines that's one of the worst things people can do that they don't often think about using the smallest amount of household cleaners that you can and the little video that I posted from YouTube about some of the typical household chemicals that we should avoid there are so many green products out there today because of our ever growing awareness of these problems so read the labels when you buy products and as we as consumers start buying more of the safe stuff the other stuff will will go away or the manufacturers will have to adjust and start making products that are safer for the environment even just putting cooking waist down sinks through our garbage disposal again we're talking about organic material which when it breaks down is fertilizer and then you know greases and oils that can be really hard for wastewater treatment plants to deal with or if you have a septic tank same thing septic tank can really get bogged down by having a lot of grease coffee grounds that kind of stuff in there and then of course you know if you have a little bit of space all that stuff could be composted instead of being thrown away or dumped down the drain I think most people have gotten away from doing these kinds of things that the people used to do a lot when people would change oil on their cars they would just dump the oil and driveway or or dump it somewhere out you know I'm the property or if they changed anti-freeze or any of those chemicals little extra gas and a gas can that got a little flat over winter I just kind of dumped it on the driveway or dump it on plants they didn't want to grow people just didn't understand how connected everything is so hopefully we all understand how bad that is for the environment but again more of these products are made to be biodegradable not that that means we should dump them on the driveway but you know there's so many places we can recycle oil and products that we don't need household chemicals and things that we don't need are picked up her we can take them free to you know places around town so the whole society is moving in that direction of being aware of disposing of these chemicals properly but again every one of us have to be aware of that so that we don't contribute to the problem we have plenty of problems in this country even though we have money and technology but the 1.4 billion people in the world in those less developing countries don't even have safe drinking water it's an inconvenience for us on those rare occasions when you might hear a warning on TV not to drink the water coming out of your faucet and might have to boil your water for a day or two till the system can get cleaned out but that's not a luxury that lots of people this world have they don't have access to simple water treatment water that's treated properly again they go down to the nearest river they bathe in it they they their cattle drink from it and they drink from it 250 million cases of water related illnesses are are identified every year and resulting in a 5 million people dying or more again a lot of these remote areas just don't even document these things but again it's safe to say that millions of people every year die because they don't have access to clean water to drink so municipal water around cities in developing countries is a huge problem again they may start having large populations and they may start having some rudimentary system but generally they don't have the infrastructure like we do a lot of sewage in these really big cities is still dumped directly into the nearest river or the ocean and again then every other person that depends on that water is is putting you know them being put at risk for for diseases the Ganges in India which is its holy river is used every day for bathing for washing clothes for drinking for everything that I just mentioned earlier it's very polluted largely by untreated sewage and all the industrial waste is being dumped in there as well as its typical prob practice for people who pass away to be burned at the edge of the river and their ashes to be put in the river and so again creating another sort of waste China again second of the largest country severe water safety issues in and around the big cities because they just don't have the wastewater treatment facilities in place so again I I know I've said this several times but I just want to end by reminding us every one of us should be thinking about every little thing we can do to conserve water whether we have a lot of rainfall or a little it becomes a habit that we just are used to doing we get used to not taking this long showers or just all the little things that can add up to tens of gallons of water every single day and again then it becomes just a normal part of our lifestyle we don't miss certain things and with every one of us doing that little bit we can definitely as a whole then make a difference
