Science Question of the Week -- Where Does YOUR Rainwater Go?
Last Sunday, we were watching the History Channels The Shape of the States, when the host of the program asked five or six people, Where does the rainwater go that falls on your property? No one had any kind of answer, and looked at him blankly, as if to say, I never thought about it! I felt the urgency of a kid in class that has the answer and waves his hand frantically, while the teacher ignores him In short, the question is a good one. Where does the rainwater go that falls on your property? Got any idea?
The host on the program made one good point, It all depends on where you live. He is certainly right about that! However, the very nature of the precipitation and the overall characteristics of the climate and land area around your home will dictate what happens to the rainwater. For example, a long, slow rain will allow more water to soak into the ground, recharging the water table below, as opposed to those quick, gully-washers of a thunderstorm, which offer little time for the rain to soak into anythingmost of it runs off.
If you live on the side of a mountain, with a fairly steep slope, you will have a much higher runoff factor than if you live in a broad, relatively flat river valley. Also, if you live in a hot, dry climate, more of the rainfall will be lost to evaporation than if you live in a cooler, dry climate, or even a humid climate, whether it is cooler or hotter. There will be a much higher transpiration rate from plants in a highly vegetated environment than in an area that has little plant cover, or in a city, where there are miles of asphalt.
Lets take this a step at a time; so that we can all begin to understand where the rainwater goes on YOUR property. Along the way, well pick up some interesting ideas and concepts. Not only that, but all this information will make a lot of sense to you! (THIS is why I love geologyit makes sense.) First, lets look at precipitation .
Precipitation:
Scientists have a tendency to divide everything into groups, with certain scientists enjoying one branch and its applications over another branch. The comforting thought, to all scientists, is that no one person can know it all! Precipitation is under the realm of meteorologists, although it affects everyone, in one way or another. Precipitation is any atmospheric moisture that falls to the surface of the earth. Easy, isnt it? While we can go on and on about precipitation, lets just say, for brevitys sake, that precipitation can fall as either water or ice, (which includes rain, snow, and sleet). Fog is another matter entirely. As we all know, precipitation varies in intensity and duration. Scientists of all kinds just LOVE to state the obvious, because the obvious is easy to prove, scientifically, and, in general, everyone agrees with you
The amount of precipitation per year that falls on your property is averaged, and of course, weve all heard of it: Average precipitation for this day is. However, if you want to know just how much rainfall your area gets, on average, every year, you can visit this wonderful web site , Courtesy of the Oregon Climate Service. Pick out your state, and nice map will come up and you can see, fairly well, what your annual average precipitation rate is. Just for jollies, my home in Louisville, KY, receives an average of 44 to 46 of precipitation per year. Nice. I use this tool frequently to help calculate recharge rates for aquifers.
Evaporation:
As precipitation falls, some of it evaporates back into the atmosphere, where it stays under the overview of meteorologists and weathermen everywhere. I remember traveling in Wyoming, in the month of July, and the clouds in the distance had long gray fuzz stringing from the bottom of the cloud that almost reached the earth, but not quite. Wyoming is a very dry place, with little atmospheric moisture, so the precipitation that was falling from the clouds that day never reached the ground surface. This happens in the more humid Kentucky, as well, but not as often. Every time Ive seen it happen here, our humidity, as reported on the weather report, is less than 40%-- so evaporation of precipitation while it is still in the air is a source of water vapor returning to the atmosphere, without ever having gone through the rest of the Water Cycle.
Once the precipitation reaches the ground surface, it can be caught on vegetative surfaces, (leaves, sticks, twigs), and sit there until it evaporates, or fall into a lake or river, where it will add to the volume of the surface water body and evaporate, pool on rocks and cling to surfaces, or it can eventually reach the ground surface, where some of it will evaporate. Have you ever walked up under a tree after a rain and gotten drenched when a gusty breeze shakes the tree? Had that breeze not come along, the precipitation caught on the leaves would not have reached the ground surface, and evaporated back into the atmosphere.
Humans help this process by watering our lawns, washing our cars, filling our swimming pools, and other activities. While in most areas of our country, we really dont contribute enough to worry about, in some areas, it can be important to refrain from water use that will contribute to the loss of the water supply, as the water is expensive to treat and were just sending it back into the atmosphere. (Are you listening Las Vegas fountain owners?)
Sublimation is the conversion of ice and snow directly to water vapor, via a form of evaporation. This isnt a big deal in Kentucky, (although it does occur), because we dont have that much snow and ice. But, for the western states that rely on snowmelt as a source of recharge to their surface waters and groundwater, sublimation rates can be very important!
Infiltration
Infiltration is the next step in finding the answer to our query. Some of the precipitation that falls on the land soaks in the soils at the ground surface. It first hangs around in the vadose zone, where the water squeezes around the particles of the soils and around pockets of air on its quest ever downward. (Why does the water flow downward? Gravity, my man! Thank God for gravity, or wed all be swimming in soup!) The upper 6 or so of the vadose zone is the area where many of the plants, like grass and flowers, get their water for transpiration.
Any one that has a flower pot has a portable vadose zone. When you water the flower in the pot, you can watch the water soak into the soil around the plant, until it reaches the overflow thingy on the bottom, where it pools. The moist soil above the water-logged soil is analogous to the vadose zone in the soils around your home. A lot of water that has soaked into the vadose zone is lost to transpiration by plants. Luckily for the plants, I might add. Not all plants derive their moisture just from the vadose zoneplants with deep root systems, like trees and many native species, send roots all the way down to the water table.
Another factor, besides slope, temperature, vegetation cover, and precipitation amount and duration, is the kinds of soils you have around your property. Sandy soils allow water to percolate down from the surface much more quickly than clay soils. Loamy, well-drained soils are the best for your plants, because they can retain a lot of the water within the soil for the plants to use in transpiration. The water in the soils sticks to the particles in the soil by molecular attraction, allowing the roots of the plants to use it as it is needed. Clay soils are usually too tight to have much water in between the clay particles of the soil. The plants must then struggle to derive moisture from the soil after a short period of time after a rain.
Once the water reaches the edge of the water table, it is drawn into the water table by capillary actionthe molecules are attracted to one another, drawing the moisture downward more quickly in that small area. This is called the capillary fringe, and is the almost saturated, but not quite, zone just above the water table. Using our flower pot analogy, the overflow thingy on the bottom of the flower pot acts as both a capillary zone, water table, and saturated zone. Water pools in the bottom of the pot, and is drawn up by capillary action into the soils of the pot, keeping the soil around the roots of the plant moist for a longer period of time. The water surface in the overflow is the water table, and the water caught within the overflow is the water table.
The water table is the boundary between the saturated zone and the vadose or un-saturated zone. In this area, water fills most of the spaces between the materials, and the pore spaces within the materials. Thats right, all those soils and things have pore spaces within them, and the water fills the pore spaces in the materials, as well as the spaces between the materials. Water within the saturated zone becomes groundwater, and then, it comes under the study of groundwater/soil/rocks, called hydrogeology. This is what I do for a livingIm a hydrogeologist.
Experiment at Home!
You need:
- A paper cup
- Snow, snow cone ice, or finely crushed ice
- Freezer
If you have snow available, scoop up a cup of snow, using a knife to even the top. Dont pack the snow into the cup, but leave it as loose as possible. You can use snow cone ice, or crushed ice, but dont pack it in. Mark the top of the snow/ice with a ball point pen that wont run, and place it in the freezer. Leave the cup in the freezer for at least a couple of weeks, (a month is better), and check to see the level of the snow/ice in the cup. Most freezers are de-humidifiers, so the level in the snow/ice in the cup should be lower! Thats sublimation!
Thanks for coming by to see me! Up Next: Surface Water Runoff and Watersheds!
Note: I have had 6 cups of ice in my freezer for 3 years, while Peep waits for it to entirely sublimate...
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I've been working on this since Sunday, despite numerous glitches in my mapping software at work. The photos are from the USGS, and the KGS, who have given me permission to use them as I need to do so. All I've done is crop and size the images.
The TV program ended up talking about Poland Water, a brand of bottled water. I was appalled, as I heartily disapprove of bottled water, which is monitored by the FDA, not the EPA. They lost such a good opportunity to really describe what a watershed is!!!
Thanks for coming by!
Great article!
Scientists of all kinds just LOVE to state the obvious, because the obvious is easy to prove, scientifically, and, in general, everyone agrees with you
(Why does the water flow downward? Gravity, my man! Thank God for gravity, or wed all be swimming in soup!)
These are great quotes. I used to tell my geology 101 students, "If you are asking yourself why does some geologic process work: Think Gravity. Then Think:More surface area. Most times they will not lead you wrong, and if it is on a test, at least I will know that you paid attention once in class."
The water that falls here, that doesn't return to the atmosphere, flows to the Atlantic Ocean first via the Schroon, and later the Hudson, rivers.
Rock On! Pun intended.
When are you gonna discuss the beer cycle ?
I am in it right now. Haven't started the major out-gassing events or the flow-testing yet.....
Are you a geologist, Broliver?? I never knew that! Maybe we could co- author some articles! A nd maybe we either know each other in real life, or have mutual friends!!
LOL!!!
We used to often find the "fossil" beerus bottlius...
Brokenbottlite
Great article. When my grand sons were in high school, this was a huge topic for the science classes. They studied, diagrammed experimented and on and on. They kind of got into it. I was surprised the teacher could get the kids that interested, but he did.
Your a Dowser after my own heart!
I taught earth science for 20 years, and this is a most excellentexplanation, better than most text books!
I had a hookydoo (I call all my neatexperimentshookydoos) that looked just like your diagram. Really neat, totally enclosed. Fill it up with a bit of water, seal it, and put it on a sunny window. It did a neat job of showing the water cycle. It did it all but sublimation. This is one of the harder concepts to teach kids, and I didn't have a freezer. Do you know of any other way to show this?
I am a Long Islander, and we live on one of the largest aquifers in the US.
We don't depend on the upstate watersheds.
I am looking forward to your next installment and I am printing this up for my girlfriend who has taken over my old class. (If I had my way, I'd tear the page out of the text book)
When my grandsons were doing their erosion experiments, I told them that the most accurate definition of erosion was a 10 year old boy washing his hands.
It' s so much fun! Evenwhen it's deadly serious, and you have a city' s water supply hanging in the balance, it's a lot of fun...
Thanks, dear grump!
I wish I could share that with my professors!
LOL Grump! So true!
In a land far-far away at a time long-long ago....
Haven't done anything but dance around the edges of geology for a long, long time. I do have a Bachelors degree somewhere around here... (mumbles to self, coughing as the dust kicks up from the various stacks of life littered about him)
Sure, that might be fun to team write an article. I like Geology, and just about every other thing that I have tried my hand at over the past 30 years. I was that annoying kid in class who always knew the answer to the questions that the teacher asked. One day, I think it was in Earth science, my teacher made me sit under a lab table... He would ask the question, (crickets chirping)... my hand would raise involuntarily, smack the bottom of the desk. Finally, I could contain myself no longer and shouted out the answer.... :/
Bless your heart, that must have been traumatizing!!! Good for you to give him the answer, whether we wanted it from you or not!
I loved earth science, and knew, in 8th grade, that I wanted to do something with earth science, which is a whole lot more fun than any other kind of science. At least to me! Besides, as you say, it makes sense. Rocks roll downhill. Big rocks land on the bottom and little rocks fill in the spaces between the big rocks. It's SUCH fun!
It's good to know someone to partner with!
I know that you'll think I'm nuts, but I worked in Great Neck, NY on Long Island many years ago, in wells drilled into the Magothy aquifer! WOW!
I read this while I was rolling my hair at home and thought, hmmmmm, I don't know... But, on the way to work, it occurred to me that dry ice sublimates in normal termperatures. That might be a thought! I know it isn't easy to find, but if you could find some, it might be of use as a hookydoo!
I taught earth science and physical science for 3 years, over 30 years ago... I taught, Astronomy, Meteorology, Geology, Physics, Chemistry, Auto Mechanics and Aviation. I loved the subjects! What fun!!!
Dear Perrie, we have LOTS in common!
LOL, dear Grump!
Our backyard is a pretty good definition of erosion, too! Erosion via canine...
Fantastic article Dowser!
Our rain water eventually winds up in the Red River...one of the muddiest rivers you will ever see. Never paid attention to rainwater 'till visiting Colorado while my sister-in-law lived there. Rainwater is a very big deal there and there were some attempts to prevent folks from collecting rainwater from their own property. Same ol'wranglingover resources.
Raparian rights, is what we call it... Here, while the water company doesn't want people to collect rainwater, the sewer district DOES! But, we have no laws against it, and rain barrels are a big deal.
It's a whole different matter out west where every drop of water is precious! (Every drop is precious here, too, but not as criticial.)
Thanks so much, Larry-- I'm really glad you liked the article! I just finished Part 2, and will try to publish it this evening.
Thank you!
I spend a lot of my time at the water company writing educational materials for homeowners, and this is a subject near and dear to my heart!
Thank you, again!
That is bad. But, as I've told my husband for years, the day of reckoning is coming.
All those deep aquifers are going to dry up, and they are not being recharged. It took millions of years to form them, and it will take millions of years to recharge them, especially when there are continual droughts.
Hoover Dam has now dropped to the point that the intakes for the City of Las Vegas have been lowered 300' below the original level. Yet, all those fountains, etc. keep spewing precious water up into the atmosphere to evaporate, and homeowners/etc. continue to water their lawns. If they want to live in a desert,LIVE in one, darn it! STOP watering the lawn! They waste more water than they ever use...
SIGH!
I can't imagine lettuce being grown in a desert. I mean, does that make sense to anyone?
OMG, You worked in Great Neck. I live 2 towns away in Roslyn and my in-laws live in Great Neck. So you must be a real expert on our water tables and our geography!
Dry ice is a great idea. Just a little dicey on the safety factor, but other than that... perfect! Thanks a bunch!
I can't believe you taught all those subjects! You are one bright lady. It seems you tend towards the physical sciences and I go more with the living sciences (although I did teach basic chem and of course coveredAstronomy, Meteorology, Geology, Physics... but nothing likeAuto Mechanics and Aviation. You are aRenascencewoman!
And yes we do have LOTS in common!
Not ya usual chixs, LOL!
LOL!
Dry ice was the only thing I could think of, for sure... I wonder if ice cream stores would have it, as opposed to having to track some down... I know it has to be hard to drive all over creation on Long Island-- having done it in rush hour, before, in a rental car that bucked. Yep, Great Neck was a great place to work! Everyone I worked with were lovely people! (I was so lucky to always get to work with nice, friendly, kind people!)
Get a carbon dioxide cylinder. Then you can make dry ice at will.
Wear heavy gloves (CO2 will "burn" you it is so cold, frostbite! Eeek!) Wrap a heavy towel around the nozzle such That you have enough enough free space for the dry ice to accumulate and turn on the nozzle. Voila, dry ice!
At least, that is how we did it when I was in school.
Wow! I wonder if we could do that with the CO2 tanksat work...
Can't remember the valving, but I think that it was pretty much straight forward. The trick is to catch it in something, the towel, and to let physics and the gas laws work. The CO2 is under pressure in the tank, and when that pressure is released it undergoes the phase change to a solid because the pressure differential is so great between the room temp tank and the rapidly reduced temperature (after all, the gas laws are in effect) of the co2. Makes me wonder if there is a you tube video
Perrie, did you ever read my "Hick in New York" series? I need to republish it somewhere.
Our tank at work is likely 15' high, and 5' diameter.. I' d likely get into real trouble if I tried to use it to make dry ice...
Oh well!
[[riparian rights n. the right of the owner of the land forming the bank of a river or stream to use water from the waterway for use on the land, such as for drinking water or irrigation. State laws vary as to the extent of the rights, but controversy exists as to the extent of riparian rights for diversion of water to sell to others, for industrial purposes, to mine the land under the water for gravel or minerals, or for docks and marinas. Consistent in these questions is that a riparian owner may not act to deny riparian rights to the owner of downstream properties along the waterway, meaning the water may not be dammed and channelled away from its natural course.]]
As long as it's not ' official', maybe I could. The company loves to sell water...
Love you, dear Neetu!
thanks for the definition!
Most states around us, and we do, too, have laws that state if you ruin someone's water supply, you have to replace the supply. So, up in Northern Indiana, when Corning Glass de-watered many square miles of land that contained the "middle aquifer", they were required to drill new wells for all those homeowners...
The "middle aquifer" is an un-named aquifer occurring approximately 150' deep in the glaciated terrain of the Teays River Valley. It actuallybegins, as a rule,somewhere between 100' - 200' deep and can be up to 80' thick in spots.
Thanks, very much, for your wonderful reply!
Oh my... But, not surprising!
When the native tribes were there, they were able to balance their population's needs with the amount of recharge available. But, we've managed to move one of our largest population centers to the exact spot in the country that gets the least rainfall and has the highest evaporation rate, etc. Just WHO on earth dreamed up this nonsense? I once wrote an article with pictures showing this, and people called me nuts. They won't in a few years.
We may be trading them water from the Ohio River/Mississippi Valleys for energy. Thank God, we have recharge.
Hi Dowser. Very interesting article!
I don't believe we've met. I am an old friend of Perrie's (and Matt & their two lovely teenage daughters, and one mischievous pussycat who goes by the screen-name of "Wally"). The picture is from this article. Left to right: Matt, Perrie, myself, Larry's wife Arlene, & Larry on the beach of Easthampton, L.I.
Are you really a dowser? The reason I ask is because the night before last a friend invited me to a meeting of the NYC Dowsers. I didn't know anything about dowsing, but learned a lot there. It was quite fascinating!
It certainly is!
I'm a hydrogeologist-- I do all the work in the professionally accepted manner. BUT, before we drill, I use a green forked stick, and 'witch' it. Sort of an added insurance!
Wish I could have gone to your meeting, I'm sure I would have learned a lot!
PLUS, it is very nice to meet you!
Hi Michael! Hows it going?!
:~)
Good idea! Science can be pretty accurate....but just in case I suppose its always a good idea idea to have a backup....
Previously, I had known just about nothing about dowsing. Several interesting speakers were there. Perhaps I will go to another of their meetings in the future.
Nice to meet you too.
Good-- how's by you?
I've been going to more interesting events (like the dowsers' mtg)-- lectures and and so on.
The Water Cycle ... I used to ride one to work.
But seriously ... thank you for immersing us in knowledge.
Thanks, dear A. Mac! I thought everyone might like it...
I can always count on learning something in your "Earth Science" class. You now rank up there with Thomas Jefferson and his use of usufruct as it relates our earth. Riparian is definitely in that ball park. And of latin etymology too. Riparian from ripa, bank of a river or shore. [Riparius (m.), riparia (fem), riparium (neut)]
Always know who is upstream and how they use the water.
BTW- Speaking of Great Neck, I know you are modest, but the Great Neck series of yours was always one of my favorites. Very good.