28 May 2009

Tarps on Reservoirs Bleg

One of my engineering friends suggested that it's possible to create water "rights" by covering a reservoir -- as cement lining of an earthen canal can "create" water by preventing it from seeping away. That water, of course, can then be sold elsewhere. (I suppose that Ray would call this "non-tributary.")

Is this a legal way to "create" water? If so, why isn't it done everywhere -- like in LA. Please tell me!

Bottom Line: It's unlikely that you will find $10 on the road, i.e., "if it's too good to be true, it is."


WaterSource/WaterBank said...

Please don't put "words in my mouth"...!

Every thing I have ever said to describe the nature of my NON-TRIBUTARY fresh water Source for CA & NV is accurate and must be completely defendable in the highest Court in the land !

As for creating a "water right" by covering a reservoir and showing that a savings in water has occurred, a plus in the consumptive use side of the equation could occur.

The value of a "water right" rests solely in the records that substantiate how much water was consumed ... ie consumptive use.

A reservoir captures water when it is legally in priority to do so. I need a hypothetical storage facility to explain, so let's say your reservoir holds 100,000 acre feet and has a known surface area of 500 acres.

Let's assume that your reservoir is "on stream" rather than "off stream", which means that the river/stream runs into the reservoir and back out again.

There are undoubtedly senior surface water rights that pre-date the storage water rights of your reservoir, so when the stream comes under "call" because the seniors want their surface (stream flow) water, you have to 1) stop storing and 2) decrease the amount you have in storage to compensate for evaporation losses.

Computations of inflow, outflow and evaporation losses are usually done on a monthly basis.

Depending upon where your reservoir is located in elevation, your evaporation losses will be between 3 & 7 vertical feet per year. Each month of the year will have a different evaporation loss based on data that is acquired from pans that are monitored by government agencies in your particular region (called pan evaporation numbers).

Let's say your evaporation loss per year averages 5 vertical feet. Assuming the walls of your reservoir are straight up and down ( which they can't be), your 500 surface acre reservoir would evaporate 500 X 5 or 2500 acre feet per year which would be subtracted off of the use of your 100,000 acre feet of total storage. If somehow the reservoir were "covered" to eliminate that 2500 AF loss, it would simply be available under the existing storage water right, ... not a new water right. The same holds true for efforts that are made to line canals/ditches ie the All American Canal lining which prevents 68,000 acre feet from escaping for the benefit of San Diego and to the detriment of Mexicali which has enjoyed the recharge made possible by the seepage.

Such legal & administrative rules is why it is so hard for CA, NV, AZ and the Bureau to consider a simple investigation to verify that a MILLION acre feet of new NON-TRIBUTARY fresh water is possible for the region.

Such a Source solution is just too big a number for them ...

To think that a new Source could be developed without damage to the environment or the water rights of anyone and be accumulated to keep Lake Mead reasonably FULL with 28.5million acre feet and generating 2000 megawatts of RENEWABLE ENERGY each year is beyond their collective ability to formulate a legal way to receive a complete confidential disclosure of the Source for FREE!

WaterSource/WaterBank waterrdw@yahoo.com

Mister Kurtz said...

Raises hell with the water-skiers.

Fixed Carbon said...

Fishing sheds, which purchase holes in the tarp through which to drop their lines? A huge new source of revenue. We need to call Garrison Keillor in on this one.

Mister Kurtz said...

On a more serious note, the biggest problem I see (presuming the economic and engineering issues are not a problem) is biological. Everything in the reservoir except anaerobic bacteria will die. I suppose the methane could be harvested until all the drowned Vegas gangsters and other stuff rots away, but the fish folks will go nuts. I don't suppose there is anything too precious in Lake Mead, (doubtless the Friends of the Chub are already fulminating) but there sure is in Shasta, Bonneville, other huge reservoirs.
A biologist might be able to figure out if it were practical to have a patchwork of tarps that would allow oxygen and sunlight to keep the critters alive, but of course the holes would allow evaporation, and such a design would increase the cost while lowering the yield. Then the water users and enviros could have a whole new thing to fight over. And the water skiers would still be pissed.

WaterSource said...


You asked a water rights question based on your engineer friend's suggestion. I simply gave you a detailed evaluation so that your readers might benefit by further understanding water rights administration and consumptive use credits.

Under no circumstances would I suggest actually salvaging water in this manner. Needless to say, it would not be economically nor environmentally feasible. As Mister Kurtz points out, the water quality problems that would be created would be disasterous.

David Zetland said...

@Ray -- sorry to "put words in your mouth" and thanks for the useful explanation of how evap losses are calculated. I am confused by the AAC lining story, as those 68,000 af were SOLD to SD as "gains from conservation." Please explain.

@MisterKurz -- good point on biology. Skiers, I am not so sure :)

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