Monday, November 17, 2008

Rainfall Calculations and Blogger Friends to the Rescue, OR 59 Thousand Gallons of Rain on the Ground

Jeanie, here you've just gotten married only hours ago, and now you're already solving mathematical problems for the weak-minded, rain deluged Louisianians!? You are a generous "jeanie-ous"! Thanks, my lack of working out math problems past 1+3=4 or something like that, sorting out the bills and bank statements, etc. has made me weak-brained, I'm afraid. I used to like math, though I never excelled in it. (another post sometime, maybe.)

THANK you for the web site you mentioned. I went there and worked with the lovely formula. Since I'm not a surveyor, and since I'm assuming (and in good mathematics one never assumes anything) that our property is the approximate 1/2 acre I was once told it probably was, I'll use the figure of 21780 square feet to be the figure to monkey with. So after all the calculations, checking of calculations and thinking a bit and rechecking my calculations, I've arrived at a number to represent (perhaps loosely) the possible number of gallons that fell on our entire property last week in a 24 hour period. That number is . . . drum roll, please! 59,735.28 gallons total (give or take a few inches, or quarts, or sprinkles, or . . . whatever!) Anyway, after finding another formula, I came up with this way of determining how much water fell in my yard (approximately, of course) by using the following chart found at Somehow, it looked easier to comprehend, but the math works out so closely, it's all good! (In case you're wondering, the chart didn't copy, so this is what did copy!)

Amount of water received when an inch of rain occurs
Area Area(square miles) Area(square kilometers) Amount of water(gallons)

1 acre .000156 .004 27,154 gallons

Just to make it easier on myself, this is how I calculated:

Whereas 1 acre of surface = 27,154 gallons of water per 1 inch of rain

27,154 x 4.4 inches = 119,477.6 gallons on 1 acre. With me so far?

Then, since I only have approximately ½ acre of surface, I divided the 119,477.6 gallons by 2. That equals 59,738.8 (which is really close to the above calculations) then since a ½ acre equals 21780 square feet, the number of gallons that fell that day must be . . . 59738.8 divided by 21780, or 2.74 gallons per square foot, or something remotely close to that figure. Nearly 3 gallons of water over a square foot in one day. I think I need to get a cistern and work out a capture system to save some of that liquid for when the rains don't come! (Almost forgot to convert to liters for my friends "down under". It's about 14.16 liters per square foot.)

Whew! My brain hasn’t worked that hard since I took a college pre-calculus class over 11 years ago. And as you might guess, my ten year old son, who came with me (I was home schooling him—you might say) helped ME with MY homework for that class. What a twist, huh?

So, thank you Debby and Jeanie-ous for taking me more seriously than I take myself and actually helping me find a way to figure it all out.

However, I still want to know . . . don’t mind me if I seem a little silly, ‘cause I am, but what about all the pine straw and leaves that fell at the same time with the rain, and whether it sprinkled or torrentially poured, or the wind blew some of my rain onto the street or into the neighbor’s yard, or . . . or . . .

Okay. I’m stopping. It’s very late and my soft brain has done all it can do for one day.

Thanks again to my friends, and Jeanie, enjoy being married. Kiss V and ‘Salina for me. (I hope that doesn’t scare any of you, too much!)

I’m calling it a night. I’m not going to dream about rain, either. In gallons, or cubic or square feet. I’ll probably dream of the cleaning, scrubbing, dusting, washing, cooking I’ll be doing for the rest of the month getting ready for and enjoying Thanksgiving with my family!

1 comment:

jeanie said...

Glad you got it sorted - we are getting a little bit, but I figure nature will work out what it needs and let the rest sit or drain away!!