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Old man on the lake

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I wasn't aware that colorado river water went to the central valley. Imperial but not central.
The Saudis have bought a ton of ag.and are exporting our water. Farmers that are down stream from these farms are screaming.
Export Livestock feed needs to come from the midwest. Maybe we can get the corn growers to grow that, rather than be stuck on the ethanol disaster.The imperial valley needs to grow fruit and vegetables.
 

John P Funk

Well-Known Member
Perhaps we should stop subsidizing ethanol? Or for that matter a million other things; renewables, oil companies(about 1/3 of renewable subsidies), lazy people, and countries that hate us. I don't see how a nation with a debt of 28+ trillion dollars can afford to give money away every day. Austerity(or poverty) is in our future and the sooner we come to terms with it the better.
 

flowerbug

Well-Known Member
I wasn't aware that colorado river water went to the central valley. Imperial but not central.
The Saudis have bought a ton of ag.and are exporting our water. Farmers that are down stream from these farms are screaming.
Export Livestock feed needs to come from the midwest. Maybe we can get the corn growers to grow that, rather than be stuck on the ethanol disaster.The imperial valley needs to grow fruit and vegetables.

actually a big part of the problem is that fixed plantings like almonds, oranges, etc. trees are what requires water that could otherwise have left gone fallow during years of drought (like this one). in a dry year, plant dry farm crops or those that don't need as much water as trees. cactus fruit, plants for tequila, etc. are more suited to dry times. alfalfa can get by on less water, but then you don't get as many cuttings.

that's many many acre feet of water tied up that really shouldn't be.
 

flowerbug

Well-Known Member
when the river gets low enough (near dead pool) would be the best time to install some bypass valves to allow sediments to flow downstream.
 

drewsxmi

Well-Known Member
when the river gets low enough (near dead pool) would be the best time to install some bypass valves to allow sediments to flow downstream.
Surf a bit on the web and you will find proposals for digging up sediment in Lake Powell, barging it to the area near the dam, and re-injecting it into the water flow below the dam. (http://www.riversimulator.org/Resou...ntationAppraisalEngineeringReport2015USBR.pdf) They mentioned Navajo Canyon and the San Juan Arm as donor sites. I didn't bother reading all 70 pages. I suppose that they needed to make some study of it, but I have doubts about the cost/benefit ratios.
 

John P Funk

Well-Known Member
in a dry year, plant dry farm crops or those that don't need as much water as trees
It seems easy to say such things from behind a keyboard. The reality is something different. Planting trees is an incredibly long term investment and can't be changed every other year depending on the weather. These farmers have made commitments not only in terms of the crop, but the equipment required to harvest that crop. A farmer that grew hay last year, can't simply change to safflower(a good drought tolerant plant) this year due to the fact that the equipment required to harvest are completely different and getting more expensive every year. There are numerous inputs involved in agricultural planning(market, available equipment, costs, and weather). We plant dryland wheat in the fall to be harvested the following August with no clue whether there will be winter/spring moisture needed to have a profitable crop. In the irrigated case, if water became more expensive(as it should according to the law of supply and demand) as Havalina suggests, things would necessarily change as farmers would have to make up the difference in costs.
 

flowerbug

Well-Known Member
It seems easy to say such things from behind a keyboard. The reality is something different. Planting trees is an incredibly long term investment and can't be changed every other year depending on the weather. These farmers have made commitments not only in terms of the crop, but the equipment required to harvest that crop. A farmer that grew hay last year, can't simply change to safflower(a good drought tolerant plant) this year due to the fact that the equipment required to harvest are completely different and getting more expensive every year. There are numerous inputs involved in agricultural planning(market, available equipment, costs, and weather). We plant dryland wheat in the fall to be harvested the following August with no clue whether there will be winter/spring moisture needed to have a profitable crop. In the irrigated case, if water became more expensive(as it should according to the law of supply and demand) as Havalina suggests, things would necessarily change as farmers would have to make up the difference in costs.

i'm saying something that should be obvious. in an arid environment growing a hard water demand crop like a tree is foolish. why should society reward people for foolish choices?

you seem to think that i'm just typing things, but i garden here but it isn't an arid climate and long droughts are rare. this year the area is very dry, the grass is already going brown, the largest ditch that runs through the property is running very low (at less than a cubic foot per second). still for me it is possible to garden within my means in terms of ground water and rains.

all the things you talk about farmers having to invest in specific equipment and such, that's a choice they made based upon false assumptions and when you ignore reality there is usually a price to pay.
 

flowerbug

Well-Known Member
Surf a bit on the web and you will find proposals for digging up sediment in Lake Powell, barging it to the area near the dam, and re-injecting it into the water flow below the dam. (http://www.riversimulator.org/Resou...ntationAppraisalEngineeringReport2015USBR.pdf) They mentioned Navajo Canyon and the San Juan Arm as donor sites. I didn't bother reading all 70 pages. I suppose that they needed to make some study of it, but I have doubts about the cost/benefit ratios.

that would be an expensive way to do it, but we do move fish around by truck in places too when needed. :)

i was thinking more in terms of dead pool river running where sediments would actually be arriving in the area of the dam to make this sort of thing worth doing, you keep the dam for flood control and power generation in the years when there are enough rains to make it work.

i think any dam now built should include such a sediment bypass valve so that both the cooler water and also the sediments can be let go downstream when the conditions are right for fish spawning and ensuring survival of the species which need the cooler water in certain seasons. and any existing dams that are getting major work done should also be retrofitted if sediments and temperature are issues for those rivers. like requiring fish ladders it just makes sense to include thinking in design about how to make it possible for the fish to survive even when we're using their water.

i do agree that the dams were built for multiple uses and they are serving those purposes now during this dry spell. i just wish there was a way for the entire system to be let loose just a little bit more so that the whole river (including some of the delta) does actually flow again like the river it once was.
 

Bill Sampson

Well-Known Member
that would be an expensive way to do it, but we do move fish around by truck in places too when needed. :)

i was thinking more in terms of dead pool river running where sediments would actually be arriving in the area of the dam to make this sort of thing worth doing, you keep the dam for flood control and power generation in the years when there are enough rains to make it work.

i think any dam now built should include such a sediment bypass valve so that both the cooler water and also the sediments can be let go downstream when the conditions are right for fish spawning and ensuring survival of the species which need the cooler water in certain seasons. and any existing dams that are getting major work done should also be retrofitted if sediments and temperature are issues for those rivers. like requiring fish ladders it just makes sense to include thinking in design about how to make it possible for the fish to survive even when we're using their water.

i do agree that the dams were built for multiple uses and they are serving those purposes now during this dry spell. i just wish there was a way for the entire system to be let loose just a little bit more so that the whole river (including some of the delta) does actually flow again like the river it once was.
Flowerbug, please excuse the dumb question, but do some dams have sediment bypass valves? It sounds like a good idea.
 

nzaugg

Well-Known Member
Flowerbug, please excuse the dumb question, but do some dams have sediment bypass valves? It sounds like a good idea.
They do on smaller dams where you can open floodgates at the bottom to allow sediment flushing. Something the size of Glen Canyon or Hoover would not really work out well since you can't operate the dam on the level swing you need to create the flushing flows through the associated reservoirs. It is much easier with smaller dams where you aren't carrying multiple years of water storage.
 

John P Funk

Well-Known Member
why should society reward people for foolish choices?
Good question, why is society rewarding almond growers? It's called the free market and last I checked we weren't in communist Russia where the "smart" people get to choose what gets planted and save us all from our own "foolishness". Maybe if those almond farmers don't change their tune, we should take their land and plant something more sensible(golf courses,perhaps) and maybe move some inner city kids out there to farm the land. Wait, I think I've heard this story before, read up on the Kulaks in the history books. Almonds are one of the most profitable plants for an acre foot of water at $1200/acre foot. Alfalfa was at $175/acre foot. If you raise the price of water as Havalina suggests, it won't be almonds that disappear, it will be alfalfa and other lower value crops. The move will be toward almonds, and that will bring almond profits down slightly as supply increases, as alfalfa production decreases those prices will increase. The law of supply and demand works for water crops and nearly everything of value unless the government(or some other outside entity) gets involved.
Below is the report where the crop values appear(Note that the first sentence on page 5 reads eerily similar to my earlier post):

 
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flowerbug

Well-Known Member
Flowerbug, please excuse the dumb question, but do some dams have sediment bypass valves? It sounds like a good idea.

i think there are in some small cases, but i haven't found any for sure yet on the bigger dams. however, as sedimentation does become an issue for some dams i think the cost of boring a tunnel and installing some valves would make it a very cost effective alternative to dredging out the sediments in some dams for the future.

the really large dams the issue only becomes critical when the river and dam is operating near dead pool because otherwse the sediments are falling out long before they get down to where the dam is at. currently for Lake Powell i don't think it's close to a problem or a solution that would make sense, but something to study and think about for the future.

they put the Third Straw in Lake Mead and the lake level there is still significant, so the technology has already been at least sort of trialled. Shasta has a cool water outlet valve system but that is probably not set up for sediment movement. i think the real interesting issue here is when the cost of capacity loss is greater than the cost of the water itself then something is going to change. it may be hundreds of years for some dams, but the cities that need the water storage behind the dams will have the incentive to provide the funds.
 

Dorado

Well-Known Member
Good question, why is society rewarding almond growers? It's called the free market and last I checked we weren't in communist Russia where the "smart" people get to choose what gets planted and save us all from our own "foolishness". Maybe if those almond farmers don't change their tune, we should take their land and plant something more sensible(golf courses,perhaps) and maybe move some inner city kids out there to farm the land. Wait, I think I've heard this story before, read up on the Kulaks in the history books. Almonds are one of the most profitable plants for an acre foot of water at $1200/acre foot. Alfalfa was at $175/acre foot. If you raise the price of water as Havalina suggests, it won't be almonds that disappear, it will be alfalfa and other lower value crops. The move will be toward almonds, and that will bring almond profits down slightly as supply increases, as alfalfa production decreases those prices will increase. The law of supply and demand works for water crops and nearly everything of value unless the government(or some other outside entity) gets involved.
Below is the report where the crop values appear(Note that the first sentence on page 5 reads eerily similar to my earlier post):

The problem is, it is not really a totally free market. Water comes at an artificially cheap price, which spurs wasteful use.
 

Bill Sampson

Well-Known Member
They do on smaller dams where you can open floodgates at the bottom to allow sediment flushing. Something the size of Glen Canyon or Hoover would not really work out well since you can't operate the dam on the level swing you need to create the flushing flows through the associated reservoirs. It is much easier with smaller dams where you aren't carrying multiple years of water storage.
Thanks for this.
 

drewsxmi

Well-Known Member
When they built Hoover Dam they made a big deal about the intakes for the power plant being at the bottom of the lake, so that the sediment would be passed through and the lake would not fill up with sediment. Over time with the lake level constant there would probably be a sediment delta most of the way to the dam, with an underwater angle of repose slope down to the level of the intakes at the dam. As a wild guess I would think that the slope would be 10 miles in length to drop 500 feet. (My wild guess was way off, see below for better numbers.) The sediment gets transported pretty far by underwater turbidity currents, and I've heard stories of muddy water boiling up at the face of Hoover Dam many hours after a flash flood dumps a load of mud and sand directly into the reservoir. I don't know of any massive reservoirs that have silted in, but the flood control reservoirs below the San Gabriel Mountains have this issue on a smaller scale.

(A little more Internet research later...)

The 1986 Lake Powell Survey (sedimentation rates) https://www.usbr.gov/tsc/techreferences/reservoir/1986 Lake Powell Survey.pdf has a chart showing the slope of the sediment delta on page 30. In 1986 the slope extended from about Dark Canyon (mile 163, about 3,680 elevation) to mile 140 and about 3,430 elevation. That's a drop of about 250 feet in 23 miles, or about 10 feet per mile as an easy approximation. If we figure the elevation of minimum power pool at 3,490, that's 210 feet below full pool, so the final sediment delta at full pool with power generation draining the silt from the face of the dam would be 21 miles from the dam, which I think is between Warm Creek and Gunsight Bays. That still leaves about 100 miles of main channel from where the sediment delta is now.
 

JFRCalifornia

Well-Known Member
When they built Hoover Dam they made a big deal about the intakes for the power plant being at the bottom of the lake, so that the sediment would be passed through and the lake would not fill up with sediment. Over time with the lake level constant there would probably be a sediment delta most of the way to the dam, with an underwater angle of repose slope down to the level of the intakes at the dam. As a wild guess I would think that the slope would be 10 miles in length to drop 500 feet. (My wild guess was way off, see below for better numbers.) The sediment gets transported pretty far by underwater turbidity currents, and I've heard stories of muddy water boiling up at the face of Hoover Dam many hours after a flash flood dumps a load of mud and sand directly into the reservoir. I don't know of any massive reservoirs that have silted in, but the flood control reservoirs below the San Gabriel Mountains have this issue on a smaller scale.

(A little more Internet research later...)

The 1986 Lake Powell Survey (sedimentation rates) https://www.usbr.gov/tsc/techreferences/reservoir/1986 Lake Powell Survey.pdf has a chart showing the slope of the sediment delta on page 30. In 1986 the slope extended from about Dark Canyon (mile 163, about 3,680 elevation) to mile 140 and about 3,430 elevation. That's a drop of about 250 feet in 23 miles, or about 10 feet per mile as an easy approximation. If we figure the elevation of minimum power pool at 3,490, that's 210 feet below full pool, so the final sediment delta at full pool with power generation draining the silt from the face of the dam would be 21 miles from the dam, which I think is between Warm Creek and Gunsight Bays. That still leaves about 100 miles of main channel from where the sediment delta is now.
So many great pieces of info in that survey! Thanks for finding this. To name just a couple, there's all the stuff about sedimentation as you point out. Figure 14 on Page 30 stands out to me. In 1986, you had two areas of lots of sediment building--at the head mostly above Good Hope Bay, and toward the foot of the dam, mostly below Last Chance. That's quite an interesting profile, and can only imagine its been accentuated since, mostly in the northern end of the lake, but to some extent near the dam too.

But the other real eye catcher is the information about historic inflows. Figure 4 on Page 11 really tells the story--generally often above the 15 maf from 1910-30 (12 times in that period), and of course in the middle of that you had the Colorado River Compact of 1922, which assumed 15 maf. They might have thought that to be a reasonable planning threshold at the time. But from the 1930s into the 1970s, it was generally under 15 maf. Maybe a dozen big years exceeded that amount in those 4 decades, and a handful right on the 15 maf number, but most below the line. The big flow years of the late 70s and most of the 80s were a huge anomaly in that context, because it's been generally well below 15 maf ever since.

I'll have to study the report some more... thanks again...
 

stevenk2

Well-Known Member
I understand the premise behind building the dams, but the big picture is you're trying to turn the Colorado/Sonoran Desert into cropland, which on its' face seems rather foolish. Then on top of that, you're trying to grow crops there that require comparatively huge amounts of water to grow. Folks can debate economics and free market and human concerns till the cows come home, but in the end, Mother Nature is going to win out - the Imperial Valley is a desert and will continue to be so.
 

flowerbug

Well-Known Member
So many great pieces of info in that survey! Thanks for finding this. To name just a couple, there's all the stuff about sedimentation as you point out. Figure 14 on Page 30 stands out to me. In 1986, you had two areas of lots of sediment building--at the head mostly above Good Hope Bay, and toward the foot of the dam, mostly below Last Chance. That's quite an interesting profile, and can only imagine its been accentuated since, mostly in the northern end of the lake, but to some extent near the dam too.

But the other real eye catcher is the information about historic inflows. Figure 4 on Page 11 really tells the story--generally often above the 15 maf from 1910-30 (12 times in that period), and of course in the middle of that you had the Colorado River Compact of 1922, which assumed 15 maf. They might have thought that to be a reasonable planning threshold at the time. But from the 1930s into the 1970s, it was generally under 15 maf. Maybe a dozen big years exceeded that amount in those 4 decades, and a handful right on the 15 maf number, but most below the line. The big flow years of the late 70s and most of the 80s were a huge anomaly in that context, because it's been generally well below 15 maf ever since.

I'll have to study the report some more... thanks again...

the history of the flows in that river basin were studied and the amount of reliable flows was gauged at less than 15maf but the studies were ignored. check out the latest book by John Fleck and Eric Kuhn's _Science Be Dammed_...

"Arguing that the science of the early twentieth century can shed new light on the mistakes at the heart of the over-allocation of the Colorado River, authors Eric Kuhn and John Fleck delve into rarely reported early studies, showing that scientists warned as early as the 1920s that there was not enough water for the farms and cities boosters wanted to build. Contrary to a common myth that the authors of the Colorado River Compact did the best they could with limited information, Kuhn and Fleck show that development boosters selectively chose the information needed to support their dreams, ignoring inconvenient science that suggested a more cautious approach."
 
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