It’s water cycle time!!!!!!!!!!!!!!!!!!!!!!!!!
I love the water cycle! No, really, I do! Out of all the cycles we have on Earth, this is the one that fascinates me the most. Without the water cycle, none of the other cycles could actually happen. In fact, without water, there would be no life on Earth! In my previous water post, I talked about how much water we really have to use. Today, we are going to talk about how the water we have gets recycled so we can use it again and again.
So, first and foremost, let’s look at the cycle itself.
Thank you to the United State Geological Service for the awesome picture! You can find it at http://water.usgs.gov/edu/watercycle-kids.html.
As you can tell, this is far from circular as a water cycle might suggest. Remember back when we talked about the carbon cycle? We defined cycle as: “a set of events or actions that happen again and again in the same order; a repeating series of events or actions” according to http://www.merriam-webster.com/dictionary/cycle.
Once again, this definition stands true. Water goes up, water goes down, up, down, up, right, left, left, right—you get the picture, eh?
Sooooo, let’s look at what really happens. Let’s start with up.
First we have evaporation, which means water becomes a vapor or gas and travels to the atmosphere. About 90% of the moisture in the atmosphere comes from evaporation (Thank you again USGS, http://water.usgs.gov/edu/watercycleevaporation.html!) Oh, and how does evaporation occur? Why, the sun, of course!
Then we have something called evapotranspiration, which is the off gassing of water into the atmosphere via vegetation—you know? Plants!
We also have a small amount of water that goes directly from ice or snow (a solid) to gas without going through the liquid state. This is known as sublimation.
Oh, I forgot one. This is for my friends in the Pacific Northwest. Steam from volcanoes is another form of water going up! I think I will combine these two!
Now this guy named Isaac Newton—you know that guy? He is the one that came up with those pesky Laws of Motion and Calculus? Yeah, him! Well, he came up with this great thought that what goes up, must come down. And I think water agreed with him, because that is exactly what happens!!!
PRECIPITATION!!!!!!!!!!!!!!!! Okay, so if you are in a drought, you hope for rain. If you live in the Pacific Northwest or you want to go on a picnic and it’s raining, you probably hope it doesn’t rain. Or snow. Or sleet. Or a fog bank doesn’t roll in.
Sorry, I digress. Anyway, so when the moisture from the evaporation, evapotranspiration, steam, and sublimation become concentrated, you end up with clouds. When the clouds get too concentrated, you end up with precipitation in the forms of rain, snow, mist, or fog. I am certain I have forgotten some types of precipitation, but you get the drift—of snow. Sorry, that was bad.
Anyway, so where does the precipitation go? Well, we have snow on mountains and ice other places, and those, given the right temperature, will melt. We have rain and mist that falls from the sky. So, it goes to the ground, right?
Well, kind of. Okay, here is where right and left come in!!
Precipitation recharges two types of water: surface water and ground water.
Surface water is recharged (or added to) rivers, lakes, streams, ponds, bogs, swamps, gulfs, sounds, etcetera, etcetera, etcetera, via run off or direct precipitation. Of course, then you have snow melt which runs into streams and rivers and that water flows down to other bodies of water.
As a note, this is why you have floods in Missouri when there is a big melt off in Minnesota. The snow melts, adds to the water already in the Mississippi river, flows down river, gets to a point in the river where the water overwhelms the carrying capacity of that location, the water over flows the banks and you have a flood!
So, what does this really mean? It means you don’t have to have rain in your area to have a flood in your area! Kind of crazy, eh?
Anyway, back to water movement! So, some of that direct precipitation, runoff, and snowmelt seeps into, or infiltrates, into the earth. We call this water Groundwater. Now, groundwater is a funny thing. You see, groundwater doesn’t always move how we think it should move. It doesn’t just go tootling along. Sometimes, it just stays in what we call aquifers. Sometimes, it hangs out in areas that are sandy or rocky and does not have a particular area to call home.
Digression time! So, when you drill a well, the idea is you drill down to a pocket of water called an aquifer. These aquifers can be small or really large. The most talked about aquifer in central Texas is the Edwards aquifer.
Now, if you drill a well in this aquifer, you would drill down to the “cavern” or space the aquifer is in, and basically siphon the water out. If that aquifer runs out of water or goes low on water, your well would be considered dry. Ground water is a big deal here in Texas and they have been managing it since the Spanish colonized the area! (I would like to say thank you to Todd Strait, Education Coordinator, Clearwater Underground Water District for that tidbit—had no clue that Texas was far more progressive about water issues than California!!! If you are interested, please visit their website at http://www.cuwcd.org/aquifer-science/edwards-bfz-aquifer/. You will see more of them in the next post!) The problem with aquifers is that everyone is drinking off them which mean they can become threatened very quickly.
Now, sometimes you have a water source that is not a perfect aquifer. In other words, the underground landforms, rocks, and sediment are such that the water flows and hangs out in tiny crevices and mixed with sand. This makes it VERY difficult to utilize this water. For example, our very own Trinity Aquifer.
Once again, thanks Clearwater Underground Water District for both of these pictures!!!
However, all is not lost!!! Plants like that kind of moisture in the earth because plants and trees take moisture up from the soil and starts the transpiration process all over! Also, we have these things called springs!
Springs are spots in the Earth where the water table (water in the aquifer) is higher than the land. The earth over that point may be weaker than others or have crevices that are close to groundwater. The pressure of the ground water pushes through these spots and erupts on the surface. These springs may bring up fresh water, water with different minerals that are present in the soil such as sulfur or may come up far warmer than you would expect! This is how we get sulfur springs (like those in the Lampasas county area) and hot springs (like in Yosemite)!
Oh my. I’m so sorry! I made this a bit long. I will say that given the opportunity, I could talk about water for hours and hours. It is such an important topic! And timely too!
So, the moral to the lesson (in case you skipped to the end!), is that be careful how much water you use! It may be recycled but it can’t be renewed!!!
Well everyone, with that thought in mind, I will leave you with water on the brain and will meet back here next week with some very cool things about cleaning the water we have!
Smiles to all!