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Old 10-24-2003   #31
Join Date: Oct 2003
Posts: 97
Just because Ref A makes no sense does not mean that it will go down in flames. I don't belive that there is any need to cite examples.

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Old 10-24-2003   #32
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Jeffro and Farmer,
Guys thanks for some info, yes I misspoke and meant dams decreased surface area. I still stand by this. Water that would normally be available for evaporation is now at the bottom of a dam. This removal of water from the natural cycles is a problem and does decrease its turnover. Surface area per gallon or any other measure of volume is exactly what we are discussing. Also, I don't claim to be a meteorologist either nor do I even know how to spell it. I do know that storms dump moisture back in some areas and not in others. Just because you are in the path of a storm doesn't mean that you will experience rain. Colorado is a great example of my point. We experience afternoon showers on a regular basis during the summer. Two points arise. One, why do these storms tend to take place in the afternoon? my answer would be that this would have something to do with evaporation as the day heats up which the clouds are unable to hold as it starts to cool in the late day 4-5 oclock. Secondly, how are these storms created? once again the answer is in fresh water evaporation. a weathermap of the western u.s. is very different in the summer than it is in the winter. Winter storms are a product of oceans and large bodies of water. Summer storms in colorado pull from different sources. And if a storm doesn't gain its power in part from fresh water sources how else is a storm created over the pacific able to increase intensity all the way to the east coast? Again, I believe I'm able to be swayed with evidence to the contrary but this process just seems logical. (not all logic is backed by solid quanitative evidence and I don't have any, every thing I've said except the geometric anaylsis is qualitative and I'm confident that surface area is decreased with the building of a dam)

I'm off to try that exercise,

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Old 10-24-2003   #33
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I checked out the exercise and it is correct. More surface area does lead to more evaporation. The point is that dams create less surface area. Think about it this way: if you take two equal amounts of water and you pour one into a container that is 2 inches deep by two inches wide and ten inches long. Volume is 40 inches to the third power. Surface area is 20 inches squared. (10*2=20 and your adding a second dimension) this container represents a river. Now take the same volume of water and put into a container that is representative of a dammed river. Lets say 4 inches deep by five inches long and two inches wide. The new surface area is 10 inches squared. The river container has more surface area per inch to the third power.
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Old 10-24-2003   #34
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every thing I've said except the geometric anaylsis is qualitative and I'm confident that surface area is decreased with the building of a dam)
I guess it's nice to have confidence. Too bad you're wrong.

On another note, I recently moved out of the state, and don't have a good local perspective; somehow I doubt that the sentiment exrpessed amongst a bunch of boaters is indicative of the general population. Is ref A expected to pass or be defeated? Or is it just too close to call?

I ask just so I know how much bodily harm to threaten my CO friends with if they vote the wrong way.
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Old 10-24-2003   #35
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Colorado summer storms early in the season (June and July) are usually a result of the atmosphere picking up moisture from the snow on the mountain peaks and depositing it elsewhere due to temperature and humidity levels changing. If you have noticed, late in July, when the snow is gone, there are fewer afternoon showers. The August storms are generally a result of the moist flow coming off the gulf (monsoon flow).
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Old 10-24-2003   #36
Join Date: Oct 2003
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Ok, I'll agree that much of a storms power can come from over land. This however is due to evapotranspiration from plants and the soil; not evaporation from open water (rivers, lakes, and such add little in comparison). The poodreh river does not add significant levels of water from evaporation.

However, dams do increase surface area. Your quantative analysis was fouled from the start...because you are assuming that the river (2*2*10) had the same volume as the lake (4*5*2). No one would design such a lake. It would not be able to hold any more water than the river.

Look at lake powell. It covers 252 mi^2. It is 186 miles long. If you assume that the river was originally an average of 150 feet wide through Glen Canyon, then you get the following surface area:

189mi * 150 ft * (1mi/5280ft) = 5.36 mi^2

The surface area covered by the dam is two orders of magnitude larger than the surface area from the river.

Note that the volume of the river and the lake also differ. The lake is about 25*10^6 acre-ft. If whe assume that our 150'x186 mi river is 40 ft deep across the entire cross section, then we get the following volume:

186 mi * (5280 ft / 1 mi ) * 150 ft * 40 ft * (1 acre / 43560 ft^2) = .14x10^6 acre-ft.

Powell's volume is likely a little less than 25 million acre-ft due to its current low levels, but that would not be significant compared to the orders of magnitude in diffrence between the volumes. Equal volumes should not be a constraint when you compare a lake + river's SA.
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Old 10-24-2003   #37
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For the guys/gals arguing about surface area...

I'm not going to argue the surface area of the dam vs. river, mainly because I think you guys are looking at the evaporation problem rather myopically. Rather, I would like to see this debate go in a new direction. It seems that water left in a hypothetically undisturbed water shed, like the Colorado, would have less chance to evaporate (while in the watershed) because it would make it to the oceans rather expeditiously. If damned....I mean dammed, I think the creation of a relatively stagnant body of water creates a rather dynamic problem for you engineering types. Based on the rate of evaporation, you would have to figure out how often a new molecular planar surface occurs. Then figure how long the exposure to the evaporative elements occurs in both models - that is the free flowing model and the dammed model. Then, I think you could solve your problem. Of course, evaporative rates are dynamic based on elemental (wind, sun, etc) exposure. One thing I know - I'm against my money evaporating into some dumb sh!t politicians hands. VOTE NO on A bad idea!!!!
Looks like you've been missing a lot of work lately.

I wouldn't say I've been *missing* it, Bob.
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Old 10-24-2003   #38
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Excelent ideas tim. That might make a good doctorate thesis!
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Old 10-27-2003   #39
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Well this discussion could very well get out of my league, but that is good. Compare the conversation on this site to recent threads at boatertalk and be happy that people are civil here. Thanks for the discussion, I have some profs. who i need to go discuss this with. This is all important because water is becoming more scarce and many people throughout the world are in a position of tension due to commodification of resources such as water. For example, the palestinian/isreal conflict is more about water and natural resources then it is about religion. Many wars will be fought very soon over water. The solution, even locally, is not to allow big business to exploit this "commodity" for huge profit margins with little overhead because those being exploited are paying for it with tax dollars. Blank checks like this destroy communities. They kill ecosystems and they take away from social programs like education and healthcare that are being removed on a daily basis. We should be creating laws based on the best science available while reorienting ourselves to believe that clean/available water is a human right and wasting water is a crime against humanity and our world. Please conserve and vote for those with these ideals!!

P.S. lets enjoy it before it all gets damned (pun intended)
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Old 10-28-2003   #40
Have paddled a Quest
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Vote NO on A

Referendum A is indeed a bad deal for CO boaters. The Colorado Water "Conservation" Board would have the financial green light to go ahead with what ever project they please. Note that only 5% of the bonding authority is set aside for conservation and repair of existing projects. The CWWA opposes referendum A, and has made a financial contribution to the Vote NO on A campaign. Here are some more links for info: **,00.html,00.html

This will be a close vote, so be sure to get the word out to all friends & family.


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