ML 138419


Interview :04 - 5:43 Play :04 - More
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Father Angelos  








Environmental Recording 7:08 - 11:32 Play 7:08 - More
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Desert ambi  








Interview 11:57 - 1:35:48 Play 11:57 - More
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Farouk El-Baz  








NPR/NGS Radio Expeditions
12 May 1993

  • Egypt
    Al Buhayrah
  • Wadi El-Natrun; Saint Bishoy Monastery
  • 30.31911   30.35997
  • Desert
    Recording TimeCode
  • :04 - 11:32
  • Egypt
    Al Qahirah
  • Cairo; El Gezirah Sheraton Hotel
  • 30.03878   31.22469
  • Desert
  • Urban
    Recording TimeCode
  • 11:57 - 1:35:48
  • Stereo
    Sampling Rate
  • 48kHz
    Bit Depth
  • 16-bit
    Equipment Note
  • Stereo=1; Split track; Stereo

Water piece tape log - 4.


00:00:30 -AQ -what happened at founding of monastery?
when monastery founded, there was a church, this well and monk cells. This well is also called well of martyrs, because during raid that killed 49 monks, the killers washed their swords in this well. Presently being purified and cleaned.
00:01:45 -AQ -so fell into disuse? Yes, but being cleaned up now. still gives water. information on number of wells.
00:03:30 -AQ -any wells runs dry? No, until now nothing runs dry. Then describes day.
00:06:15 -gen'l courtyard ambi ...nice, birdy, but not too much
00:07:30 -desert ambi
00:08:43 -wind up.
00:09:00 -reset levels.
00:09:50 -wind up...good. (very light but there) good right through 00:11:30.

Farouk El-Baz, Interviewed for NGS/NPR Radio Expeditions
INTERVIEWER: Let's uh let's begin here because I know we we want to talk about this and that is the re¬lationship between the water that we see in the Nile River and the water that is a surprise to us to us who don't know about water, because we go out to a place like Elnotun and and uh the monks say I dig down three meters and here's this water. / And you take us out to the great empty desert, nothing around, and you have a crew drilling there, pfft, river in the desert. How is the water related?
FE: In uh the western desert of Egypt at the border of the Nile desert, the source of that water is the present day delta. The uh waday farok which means the Empty Valley, where the... is in Empty Valley, which sits just west of Waday Notu, and both of them are depressions. The reason for the fact that when you dig just a few meters you find water is that they are depressions in the desert floor. The water from the present day delta seeps through rock, the uppermost surface layer is exceedingly porous, I personally believe because it is an an¬cestral delta of the Nile because we've seen that shape of the delta in satellite images and went into the field and looked at it and we see these rocks right on the surface little pebbles that make a desert pavement of broken fragments of rock that do not occur locally at all. They must have been brought by the river Nile from deep in Africa from Aswan and beyond. And the combination between the fact that you see gravel and beneath it is sand mixed with silt in the shape of a delta con¬firm to us that this is an ancient delta of the Nile. Deltake deposit, meaning the stuff that is that makes the delta are very porous materials. And allows water to go right through. So when you have the present day delta with a great deal of water use that sits on top of an ancestral delta of the Nile that is very porous, all of the water that comes from the Nile channel the Nile canals the drainage canals the navigation canals and also the fields. Everything that seeps through the sur¬face and goes down below actually goes straight into the porous rock of the ancestral delta and moves away from the pressure source where the water is so it there's a gradient away from the Nile Delta and as additional waters are uh go through the uh the rock and therefore if you are west of the delta and you dig a few meters, you are going to find ground water, even very close to the surface. And as you go further and further you will find additional resources of ground water the vast majority of it comes from the recent seepage of water from present day delta.

INT: When you say recent seepage, uh uh it may not be possible to answer this question but when we see water coming out of the ground at at uh at at the sites where uh where we were drilling uh uh yes¬terday, when we see water coming out of the ground like that, how long ago was that water in the Nile?
FE: When I say recent accumulation of that uh water I really mean in historic times I mean perhaps dur¬ing the past five thousand years or so. Uh I say this because of the fact that uh if you go deeper and deeper in the rock even if you are confined within the ancestral delta of the Nile, at deeper levels you find water that is much older. A great deal of the water in the western desert of Egypt is dated back to something like 35,000 years ago. And then there are phases that are even older. So the one that is very close to the surface we say it has less than five thousand years of age. In reality it some of it might be quite recent, mean¬ing it would only take the time it will take a drop of water to go from the present day delta to the site where we are depending on how far we are which might be measured in only hundreds of years.
INT: When you're taking the water out is the same amount of water coming back in all the time?
FE: It depends on how much water you take out. The uh proper ground water use uh must begin with uh drilling several wells in various locations at the proper sites. And then pumping from one of them and measuring the effect of that pumping on the rest. And then you know that each well that is surrounded by an area let's assume a couple of miles, the pumping rate from that well at such and such rate per hour would not affect the nearest well. So if you actually pump f-uh based on that rate regularly maybe you're not going to affect the horizon and you're not going to affect the uh the level of water in general. Uh in cases of overpumping meaning that you're taking from the well more than what you're really supposed to do, then it would affect others and the infiltration of water that is coming in rather slowly as water makes its way around the grains of rock then you would perhaps not replenish the water as much as you are using it.
INT: When you say the Nile Delta is delivering water into the rock today even, how much water is sinking into the rock, how much water that we see going by as surface water is actually becoming ground water?
FE: I personally say that it would be no less than per¬haps twenty percent. Because you have the first water that goes out of the system goes out by evaporation and that's a small percent maybe ten to fifteen percents is up about uh roughlies. In the delta and along the banks of the river most of the water just goes flows northward for the uh end into the drainage ditches. Uh a very reasonable percentage of that water goes into making the the plants because the plants grow and they take a great deal of water and they also the leafy material in the plants uh allows water to eva¬porate through the pores in the plants them¬selves. Through the whole process of life of the of the plant. So you have regular evaporation, and then evapotranspiration from the plants and then some of the water going into towards the Mediter¬ranean and then I would say about 20 percent of that in this kind of environment seeping through the rock and moving outward.
INT: Is that true just of the Nile or is that true of do you think most bodies of water mo-or is that true of most rivers that that one would look at?
FE: No it depends on the way that river is and what the geologic nature of the rocks underneath the river. For instance in some cases you have a river going through uh solid rock that is not been fractured and you very little of it goes through. You go through a solid rock that's highly fractured and and enormous amount more than the Nile's case would go through. Quite a bit more. And in here where you have the delta is rather silty and the water takes its time going through the fine grains of silt until they get to the sandstone and you get that kind of work so it really depends on the basically on the poracity of the stratum of uh uh soil beneath the river water.
INT: Uh is it is it the case that uh most rivers with big delta basins uh w-would be like the Nile so that say the Mississippi and the and the Amazon would have the similar uh ground water conversion rate for surface water?
FE: In the uh Mississippi in general goes through rock that is water saturated anyway from rain much (break)
INT: We stopped at on the M-we had stopped on the Mis¬sissippi.
FE: Yeah why don't you ask again?

INT: Are other other delta rivers with delta systems are they like the are the like the Nile River's like the Mississippi?
FE: Each and every river system has its own character¬istics. In general terms the rivers provide a measure of ground water to the water below. But how much ground water is uh taken from the river system depends on many factors. The first one is the slope of the of the terrain. If the slope is very high, then water passes through very high and it has no stay time so very little of it would have the time to go through the rock. Second is the nature of that rock, whether it's fractured or not, whether it is porous or not, and all of these factors then uh make each river system unique. only in the amount of water that might seep through it and the kind of sediment that comes to its mouth but in general the rivers bring in sedi¬ment and some of the wa-the water of the river goes through the rock to be stored as ground water as a matter of of principle.
INT: Uh when you look at the desert when we think of the desert uh we think of it as a great open empty place with no water. Why is it that that uh you are able to find water there in huge quantities?
FE: When I studied geology, my perception of the desert is a waste space that has no signs of life and therefore one should not really expect any water in here. Because water has a negligible influence on the terrain and therefore a negligible in¬fluence on its history. However, the more I looked at desert terrain and the more we studied the regional setting of desert areas especially very large areas, that you can only see in satellite images because a photograph from space covers a very large area, then we began to see that there are certain concentrations of things that could not happen except by water action. For example, you see that all of the sand dunes of the world in any desert accumulate in depressions. The things that accumulate in depressions are usually carried to these places by water runoff. Meaning rain water would fallon mountain highs, break up rock, take little pieces of it, grind it as it flows, keep it running through the turbidity and ground¬ing that material into tiny little fragments which is really sand size, and then deposit it in layers in low areas. It's only when the weather condi¬tions change and the water no longer is present and rainfall no longer comes that you begin to have the wind that will actually reshape the layer sands into dunes. And therefore we should be look¬ing at desert terrain in a completely different way of thinking because we are to look at it as a place that was born by water not by wind but only reshaped by the wind. And if that if that's the case then some of that water that used to be there must still be stored in rocks beneath the surface.
INT: Why? Why must it still be there?
FE: Because no matter how small the porosity some water goes through. In most cases¿ these uh sand accumulations happen over uh porous sedimentary rock, like sandstone or limestone. In both cases water goes through very easily because sandstone to limestone have a porosity of maybe anywhere be¬tween 20 percent and 30 percent. Meaning that there are open spaces between the grains that make up rock that form 20 percent of the volume that that rock occupies. So if that 20 percent is open space, water would fill it very easily. And there¬fore, uh water over sandstone or limestone will seep through these pores and accumulate and be stored there.
INT: Um, you made this discovery uh during the during the uh uh i-i-during the time when you worked with NASA worked with space satellites. Uh I've heard a story about about how you first uh dis¬covered this in uh in in Africa when you first found these reservoirs uh in in uh uh under the Sahara. I wonder if you could tell me that?
FE: The first uh realization of the fact that the uh a major desert landforms are really the creation of water rather than of the wind and therefore some of that water would be stored beneath the surface came from the search that I did in the Western Desert of Egypt while I was uh at the smithsonian Institution there uh directing the Center for Earth and Planetary Studies at the National Air and Space Museum. And that was a ten-year period where we just emphasized the study of desert land¬forms in satellite images. And we began with uh images of the Apollo-Soyuz mission the first only joint American-Soviet mission. It was through the photographs that were taken by this mission that uh I was able to recognize the former the an-cestral delta of the Nile. And therefore began a completely different thinking about the geology of the western desert since then. Then when the Space Shuttle began uh there was a plan to fly a uh shuttle imaging radar. The shuttle imaging radar flew the first time on the Space Shuttle in 1981. During that year and the two years preceding it I was emphasizing in my research the area in the western desert in Egypt between the borders of Egypt and Sudan. I called uh Charles Alatchi the principal investigator for the and the designer of the shuttle imaging radar and asked him to run the... over that part of the world. To acquire some additional data, more than what we had from Land¬sat images. He asked what is the terrain like. said well it's rather flat and it's covered by sand and there's not too many features and that's why we need to see whether the radar would expose some features. He said uh well Farouk if it is flat and covered by sand you'll see nothing it will actually be a a useless bit of data well if you know that radar reflects back from solid rock. And if you don't have rock exposures then you'll see very few structures. Well there are maybe hills in there with very fine structures that will help us a little because we don't really see much in the Landsat images. Anyway he was convinced to run it for a short period of time to give us some¬thing. And it was really amazing because when he first sent me the strip of shuttle imaging radar data over the area that we were interested in I thought they turned the instrument over the wrong time, because I had the picture in my hands a strip of land that had three huge rivers. I said well that's somewhere else that's not Egypt. So I called them up and said you seem to have run the instrument the wrong time. They said that's im¬possible. I said what what I see in here they they sent me the tape from your lab and there's three rivers and so it's not our desert. He said it's impossible we'll check over and he checked it and said no. We turned it on exactly on the right time and it was turned off exactly on the right time. So I took the pictures back and went to re-look at it and 10 and behold I recognized two tiny little hills in that image that are in the Landsat image so that is the right place. The only difference is that the radar penetrated all of the sand cover because it has absolutely no moisture and is fine grained and it went through it as if it does not exist. And brought back the reflection from the first solid rock layer and that first solid rock layer had incised into it the channelways of three enormous rivers. One eight kilometers wide, one twelve kilometers wide and other twenty kilometers wide.
INT: These are these are three ancient rivers that once flowed through Southern Egypt and Southwestern Egypt?
FE: These are three ancient rivers that went through in Egypt within the space of a hundred kilometers. One river is eight, one river is 12 and one river is 20 and that is the total width of the Nile val¬ley, not the Nile channel, but the whole Nile val¬ley. So these are two and within 100 kilometers there are at least two widths of the Nile valley made of rivers. Enormous rivers. Must have been bigger than the Nile at the time in this part of the desert that is now incredibly dry where you can drive for 500 kilometers and not see a single blade of grass.
INT: And how long ago w-did these rivers flow, oh you must have asked yourself that.

FE: Yeah what we did was to dig through the sand uh down we were only able to go down to the about 16 feet and uh most of the things that came from the edge of the river in on the river banks were dated by by a colleague who who's a archaeologist to be just about 200,000 years meaning the bank of the river was about 200,000 years. This does not mean this was the last period when there was water in could have had water since but the oldest date that were able to to establish was 200,000 and 220,000 years ago. So here are three rivers that existed in that strip 100 kilometers 220,000 years ago supplying enormous amounts of water surrounded today covered today by sand yes, but surrounded by a flat area that has some wonderful fertile soil. So we made a plan looking into this fertile soil and whether there's groundwater or not and we started looking into the the ... of using that.
INT: Just just explain briefly w-how how it dawns on you that this is fertile soil and not just you know because we don't think of it as fertile soil we think of it as pft, sand.

FE: The uh reason for thinking about that in in terms of fertile soil is we actually found out that these rivers feed into a huge lake that may be like 250 KM ...that's the size of Lake victoria. This is some some huge lake that used to exist be¬tween the border of Sudan and Egypt. Today, which is a parched desert and and the lake deposits in general are good uh mixtures of sand and silt and maybe some carbonates that they make good soil in general. We call them pliers and these plier deposits in general are very good fertile soil. Since as soon as we found this enormously flat uh area and recognized later because of these river systems that it is it must have been a lake and actually we should see today some effects of uh wave motion along that enormous edges of that enormous lake of that are still incised in the rock and rock exposure is at some corners. So you you're standing there in an incredibly hot place where absolutely nothing lives, not a bird not an insect not a thing, and you're standing there on a place that you know that there was a huge lake that you could not see the edge of, there was a great deal of fish, there were hippopatomus we si¬we find hippopotamus teeth we and you can imagine that the whole area around it was completely gover-covered by grasses tall grasses was a savanna like environment, lots of trees here and there, ostriches roaming allover the place be¬cause we find the pieces of ostrich egg shells strewn allover the uh the place today. So it is just in a completely different setting. And then the weather condition changes~ and the rains no longer come. And all of the water on the surface evaporates. And the place becomes deserted. By plants, animals and man. Now when we go back to the place today, you see the wasteland that this on the surface but right beneath the thin cover of sand the soil is preserved and beneath that soil is a component of the water that used to be there that is stored as ground water. In this specific area, there were enough wells that were drilled and enough experiments were made in an experimen¬tal farm to establish beyond any doubt that within this area there is nearly 200,000 acres of land and the water that exists right underneath these 200,000 acres is good enough for agriculture on this land for 200 years. And that is something that can certainly help the Egyptian economy.
INT: You must confront um, skeptics on this. There must be many people who say uh alright here are your here are your satellite images and uh uh you say they mean this but I look out there and I see desert. No one you know people have given up trying to live there, if there was any worth to it people would be there.
FE: The objections we had at the be-very beginning some of them might exist to this day, are by the uh the uh people that are trained in agriculture in Egypt, most of their thinking is really con¬fined within the Nile valley and they know how to irrigate from Nile water that flows in this direc¬tion that has that kind of a slope so when you make it a a irrigation canal running this way you would have a drainage gran-canal running parallel to it and everything moves and there is a system and there is a plan. Now we go into the river, the soil might change from place to place, some of the water as it evaporated left a little bit of salt so you know how to deal with these salts that and when you don't see the water in a channel by flow¬ing in front of you as all Egyptians are familiar with this view, of this enormously wide channel with water flowing all the time consistently so they can see the water, then if you are going to depend on water that's sitting down there that some pe-people will tell you if you pump this water it will run out. But will dry up. They tell you that they exist now today but maybe next year it will not be there. It's psychologically not it it's disturbing that you're depending on something that you can't even see. Whether this water is going to be there or or not, how much can you pump for it they tell you that it's gonna be there for so many years, but how do you know that? I don't see it? How much of it is gonna, what if it be¬comes saline and I can't use it for irrigation so that all of these uh uh questions in addition to the fact that uh there were also objections as to the potential utilization of what is called fossil water, meaning that is water that accumulated at the time when there was a great deal of rain. Now there is basically no rain. So that you are start¬ing to use water that is not going to be replenished. So you're really mining water as if it is like gold or silver. You go there and you find a vein of water an aquifer and you're gonna mine it and it's gonna run out and you have to move on. So that's also unsettling.
INT: That is unsettling, I mean should should you do that with fossil water?
FE: Yes, because you do that with oil you do that with minerals. Water as far as I'm concerned is a mineral resource. Just like oil just like gold just like silver, you go out there it is one of the resources that God has given you. You look around and you look what these resources are and you evaluate the economic potential, and you util¬ize them, even if it runs out you should know when it's gonna run out and then move on to utilize some other resource of water somewhere else. So it is part of the resources that you should you should utilize for the benefit of the economy. Of course for the Egyptians when I first realized how much land was there and the time that the water would suffice agriculture on this land and I was very happy with the results and happy with myself about the whole thing and they came here and I talked about it and the first meeting and the and the geographical society here in uh Egypt somebody stood up and said, 200 years only, then it is not worth working there at all! Of course the Egyp¬tians by nature are used to seven thousand years of history he said, you you can't make a society over 200 years. I was stunned at this response. At the beginning. And I caught myself by saying, what why don't we see what the united states of America did in 200 years. You can't tell me that 200 years is too short to to to develop anything. Cause they really thought that 200 years is not good enough to do anything. And it is very dangerous to to es¬tablish a whole society in one place and then 200 years uproot them or so it is it that is also an¬other unsettling thought. What if this water real-ly runs out after 200 years and we cannot find nearby resources, uh additional resources. So that is also unsettling, so we have to take all of this into account.
INT: How do you respond to that?
FE: The response to that in general is that there is there is most likely this is not the only source of water around. There may be uh rises of water vertically that we have not thought about that we have not drilled to, or there may be sources of water farther away horizontally that we have not looked at or studied. And therefore you can think about using something that is farther down or far¬ther away. In addition, what do I know about the technologies of 200 years from today? If I have really developed this land fabulously and it is prod-producing a lot of good food and s-satisfy¬ing the Egyptian requirements of food uh security for many varieties of food and this and that, maybe after 50 years I would run a little tube from Lake Nasser or from the Nile to mix with the ground water so it would not be used fast or whatever, so there could be other ways of of uh think about that if this society that was created in the middle of nowhere based on ground water can no longer be self-sufficient for a long period of time there are other ways of doing it as long as you're utilizing this uh resource you'll be able to think about using things below it, away from it or bring some water from the Nile in the future.

INT: You know now in the united states uh, and and elsewhere in the world uh but certainly we en-countered this in urn, uh in Nebraska people talk¬ing about the Ogalala aquifer uh there there is unease and resistance to the idea of using a resource when we don't understand how to replen-replenish it when it does look as though it's being uh used up rno~e quickly than it's being replenished. You spoke earlier about the wise use of ground water and establishing a rate. Uh is that is that in contradiction to what you're saying now?

FE: Not at all. No matter what is the uh or uh not at all it really is not contradictory at all. No mat¬ter what in desert areas, water should be used sparingly. This is good for the water use in addi¬tion to the and the fact that it is best for the soil to... itself. If you use a lot of water then you leave behind a lot of salt, so it will decrease the crop productivity of the land with time. The uh the smaller the amount of water the least amount of s-salt that you leave behind so you can keep the productivity of the land for a longer period of time so you should use the least amount of water no matter what. In addition to that, the use of the rate of uh water should be planned because if you create a society and the society is based on agriculture and then you find that agriculture is taking more water than its share for the living of the people then you can re-reduce agriculture a little and let people's use come as a first priority. We have this problem in the in the Southwestern States in in the united States even California where we have water being used both for municipalities and industry and water used in agriculture. If the agricultural community uses a great deal then that will hurt the potential sources for uh water for municipalities and the uh and the uh industry. And if that happens, then you can lessen the utiliza¬tion of that water in agriculture for the benefit of municipalities and and industry so that there is there should be a a balance and there should not be a uh a sta-or a uh stage of utilization of all of that water up to certain limits consistent¬ly. The use of the water can change with the with the time. In addition to the fact that it is best to know how much water is there how much I'm going to use and when will it run out and what do I do next. I personally believe that the problem of the Ogalala aquifer was quite well-known from the time of the utilization I remember as a graduate stu¬dent in the uh in the united states there was quite a bit of discussion about that ogalala aquifer and it was that it would the water if it is used at such and such rate it will run out in in 20 years. And indeed the level that went down to that became to shake up people was about 22 years from that time. So if we know what how much is there, and using it at such and such rate when it will be become scarce and when will it uh real¬
ly become to hurt us, then I should be planning of what do I do next. Like in Egypt. If we find that these 200,000 acres are going to be only for 200 years then at about 150 years from ~oday I should begin to think, Okay, what do I do? We have fifty years from today. If you know how much, what is the rate of use, that's safe rate of use, and what do I do next then it will be perfectly alright.
INT: Let me ask you a a few more questions that that derive from satellite imaging and remote sensing. Um, Russ do you want some coffee or to take a rest of your arm or anything? Okay? Um, how useful is this technology what do you see from the satellite images that that uh that helps you, and and what is the application of it that is uh could someone listening to this program say gosh he he -did that because he was studying Egypt uh let's let's get him to look at Arizona let's get him to look at uh Central China, let's look at Central Australia. Uh you know maybe maybe there's water everywhere or or look at uh you know other parts of the united states.
FE: Very good this is an excellent question because it really relates to how do you begin to look for water in today's science. One of the most sig¬nificant things as far as the location of uh ground water is the understanding of the drainage pattern. Meaning when a drop of rain falls on that spot what happens to that drop of water, where does it go, how fast and where. That you can see from the system of drainage, the little streams that connected to bigger streams and bigger streams and on until it goes into a major river course. That tells you a great deal about the slope, the nature of the rock, the uh how fast would will water go along that uh surface. Whether it will erode in it or not, and how much of that water have would potentially go through to the ground. So first of all you really figure out the the drainage system and the drainage basin of the area. Next you would see whether this area is fractured or not. Because the more the fractures in the rock the more the porosity of the rock the more it has capacity to accumulate and keep water. Then you make a relationship between the drainage basins and the drainage lines the streams and the fractures. If the stream is coming at right angles to a fracture, then it will just pass by and move along. But if a stream comes along the fracture, then its stay time over the fracture will be long, it would be a long period and a great deal of that water will seep through the porosity of that frac¬ture. Therefore you're actually looking at the up¬permost surface layer only. And satellite images a satellite image does not tell you anything about the subsurface at all. It just give yous gives you the nature of the terrain and outermost layer. And from the outermost layer you interpret what the subterranean structure might look like. And there¬fore since we don't really know how to tell here is water and here is oil and here is mineral, all you really do is to select the best spots that have potential. So that you after the selection of a spot that has the most potential or the li-the most likelihood, then you go into the field and do the...physical surveys to figure out the exact en¬vironment, and then select a exact point for a well to dig. So it real the satellite images I think they're best use is to help you to select the places that have the gretest potential. Now if you take that technology and apply it in a desert area, then it is easy for you to apply in other desert areas. with no question at all because you gain expedience as long as you are trying to fig¬ure out where water collects and where some of it might be stored. If you are working in uh highly vegetated terrain, you need the people that know about how much water goes into this kind of ter¬rain where you have a great deal of forest and what happens because the vegetation plays a a very important role in the concentration and dispersal of water. So to be able to pick up the way water would accumulate in uh in areas in high vegetated terrain like in a forest region like the Amazon or in Central Africa then you'd have to have somebody that knows how to do that and therefore you can apply all of that knowledge in these kinds of of uh of terrains anywhere else.
INT: But would you be able to use the the the uh would your your radar work the same way that it did revealing these .these rivers to you in say central Australia in uh in uh part of the the American uh uh desert in utah and Nevada and indeed in uh well high plains are vegetated although that's called the great American desert bit it's it's vegetated.
FE: Yes the the satellite images as you look at them they can work in the all deserts in the world in the same way. The radar images that actually pene¬trated through the sand to take to give us a view of the first solid layer beneath the sand would work in any sandy area, that's why we for instance we have plans for the same kind of photography in the Western Sahara and the Arabian Peninsula and in parts of China and so on, because the radar has the capability to go through fine sand that has no moisture or the least amount of moisture go through as if it does not exist. To reveal what is beneath it. So the answer is yes it would work in the same way provided the sand is not wet. The only places where the sand might be wet it would not work may be Nemedia where you have a great deal of fog and sand has a great deal deal of moisture, and in some parts of Australia where there's a great deal of moisture with the sand it¬self because moisture tends to reflect the uh radar rays waves so the radar would not be able to penetrate it.

INT: When you talk about the dryness of sand uh, the the dryness of a region, uh we think of uh parts of uh uh our American landscape as being very very dry, uh but you're talking about a whole nother scale of of dryness here. Uh how do you measure that and what what is it that you're measuring?
FE: There's the measure of of uh oh, how to say, yeah dryness is a matter of degree. The uh best way that we are able to measure dryness and compare different desert areas is by aridity index. Which is a relationship or a ratio between the uh received solar radiation and the received rainfall over the same area. And this uh ratio in the driest places on earth the very very dry areas which is a tiny little strip in South America and a whole vast part of the Eastern Sahara has an a measure of what a contour line around it that says 200. That 200 means that the the received solar radiation is capable of evaporating 200 times the amount of rainfall. But these are the driest places on earth. Particularly in the eastern Sahara. Most of the deserts of the world have the real dry deserts of the world have numbers between uh 10 and 50 and that includes the western Sahara the Rorahali, the Anterquart of Arabia the Tek¬lamakan desert of China and the Rajistan of India and uh so on. The uh the American southwest, the driest place in North America is called Death Val¬ley in. California. And the number for that is seven. So dryness is certainly a matter of degree and the uh the the North American uh deserts are not as dry as most of the deserts of the world.

INT: Uh earlier when you were you were uh telling the story of the discovery of these rivers and you you went back and told the geologic story of the formation of uh of the Sahara desert uh you de¬scribed how different it it was how wet it was then you said and then the weather changed. The weather pattern changed. How oft-how how does that occur an how often does it occur and is it ever gonna change back?

FE: And when I say the weather uh changed I mean that there was a major change in the climate. It is something that must have been part of a global change in weather patterns, because what happened is that an area that used to receive over 100 mil¬limeter uh of rain per year and now gets less than 10 so this is a major change in in weather uh pat¬tern. And as far as we can tell the oldest thing that we see from this the present dry spell that we live through now something like five thousand years ago meaning that uh five thousand years ago all of the North African d-uh Sahara, including all of the western Desert of Egypt and and the Sudan and all of the Arabian Peninsula and so on, was wet or was experiencing wet clima~tic condi¬tions five thousand years ago. Between five thou¬sand years ago and eleven thousand years ago the wet period persisted which means that the lakes in the Sa-in the Sahara existed the rivers were had water flowing in them and there were glass¬grasses on the land and there were trees and there were animals and humans allover the place.
INT: This is during the time of the civilization the foundation of civilization in in in Egypt seven seven thousand years ago w-the land would have looked substantially different even then.

FE: At the beginning of the Egyptian civilization the land would have been very different then, and all the beginning of the, maybe not the beginning of the civilizat-at the at the beginning of Egyptian history that is recorded today, the conditions in the deserts of Egypt would have been very dif¬ferent, because this is seven thousand years ago and there was still some grasses and some lakes and some trees and there were all kinds of people roaming allover this place. But the real age of the creation of the state in ancient Egypt was about five thousand years ago when the two coun¬tries northern Egypt and Southern Egypt, separated by Memphis which is near Cairo, they were two dif¬ferent countries and they were unified and they were ruled by the same Pharaoh and there was an organization and a real state from the Mediter¬ranean all the way to Aswan. That creation of the state is exactly five thousand years ago and that is what we find from geologic uh geological evi¬dence is the change in the weather condition over the Western desert of Egypt.

INT: Do you think that's a coincidence?
FE: Not at all. From this I surmise I personally be¬lieve that between five thousand years ago and and seven thousand years ago, the conditions in the western desert region was okay for a lot of people to live. So people lived around this place, and they produced enough food and they had all kinds of animals roaming and they hunted them and lived fine. And uh when the dryness began to occur five thousand years ago therbegan to emigrate and find a source of water.
(end of side one)


FE: ...kept on getting away from the lakes and farther away and so on until because the lakes began to dry and the when the final drought occurred just about five thousand five hundred years ago, they moved all of them to the only source of water that was trustworthy which is the Nile. So they all came the whole population from the desert on to the Nile valley. Now the Nile valley was not empty, it was filled with people using agriculture and doing all kinds of things for for at least two thousand years, as far as we know.

INT: Already there when the people from the the western Desert...
FE: Already there.
INT: ...showed up and said uh...
FE: Showed up and said make me a place in here. And it was really when you had that infusion of popula¬tion in my thinking that you had they had to organize so that the land where you had a limited population would be good enough to be utilized to feed an additional population. So they had to organize things a little better. And that was the the the basis of the state when you're organized and you have you can divide the labor between society and you can let these people do this and do that and do this you produce this and so on so on. Soon as they organized they created the con¬cept of the state, and that allowed them to have high concentrations of individuals in cities and uh these people were able to eat and feed them¬selves without having to produce food because somebody else is doing this their job for them, and they began to do good they were the artists would make better art and the musician would make better music and the...would find more resources and they began civilization.
INT: So a-you you find water the lack of water actual¬ly, uh the demand for water as uh uh an organizing force for civilization.
FE: Yep. Because it was a demand for uh organization of the labor force and uh and utilization of the resources and the best possible way because the population was increased many fold instantaneous¬ly.
INT: Um how often do uh as as a geologist how often do you see these changes in in uh weather patterns this one was uh very dramatic maybe you this hap¬pens uh you know once I don't know every five thousand years or something and but and but but how often do you see significant changes in in weather patterns?

FE: First you go to this lar-rather ra-large segments of uh of thousands of years of different kind of environment. The uh present dry spell the present drought in the Sahara and Arabia began five thou¬sand years ago and between five thousand years ago and eleven thousand years ago the ha-the whole region experienced a wet climatic conditions. Be¬fore that there was another wet period. I'm sorry, before that there was another dry period. Before the dry period was another wet period that per¬sisted between 25,000 years ago and 35,000 years ago for 10,000 years. And before 35,000 years ago another dry period. And before that another wet period between 45,000 and 60,000 years ago. And so on that goes back until the wettest of all the pe¬riods, which was somewhere around 200 to 220,000 years ago. So we know that there has there have been uh wet and dry climactic periods and these cycles were over many thousands of years. within the last five thousand years there were also cycles. Perhaps even one or two thousand years be¬cause the ancient Egyptians talk about uh droughts in their in in their uh written history. In addi¬tion to that we found that the Nile records kept by the ancient Egyptians during the last 2,000 years, uh tell us that there is a cycle for the river floods a great deal of water to much less a great deal or much less and so on everyone hun¬dred and thirty five years. And superimposed on that is another cycle which is about 22 years and this cycle is wetter more more wet and more dry and more wet and more dry and so on. That appears to be related to the uh spo-the uh the cycle of the sunspot because it is 22 years. In addition to all of that the smaller cycle that we know for certain is the seven year cycle which is every seven years you have a dry spell or a wet spell for ex-for example and this we're all familiar with we have seen it, in my lifetime, uh even as a scientist uh between 1968 and 1973 there was an enormous drought that affected the northern Sahara very badly and and uh thousands of people died and thousands hundreds of thousands of herds died and so on from during this period. And that was fol¬lowed by a wet reasonably good uh period and then a drought again came between 79 and 86 and then it is a much better condition uh right now and then maybe we believe that there is another dry period that comes after that. And this is the period that is uh uh written up in the in the the Bible, giving us an an idea that there is a change be¬tween uh wet climates and dry climates and wet climates and dry climates from the from the story of Joseph who interpreted Pharaoh's dream talking about uh seeing uh seven cows one fat and healthy followed by by some of them that are shriveled and thin and blasted by the East wind and so on and so this was something that even from from the ancient uh uh culture came to us to tell us that there are cycles uh cycles upon cycles of this wet and dry. And the cycle that we are familiar with in daily life is that of the seasons because these are really climactic cycles that depend on the move¬ment of the Earth along its axis and the position of the Earth relative to the Sun. Because this whole weather engine is driven by the dynamo that's called the sun. The energy from the sun af¬fects the amount of rain that comes to earth.

INT: Urn, let me go back and ask a ask a question that uh uh k-kind of I didn't ask earlier, uh b-but it follows from something earlier. If you take the water out of the ground you take fresh water out of the ground, you use it. What happens to it?

FE: What happens to the water is three things. Some of it goes right back again. Back into the reservoir or back into the the uppermost soil anyway. Part of it evaporates instantaneously, and part of it would fill the the plant root the plant stem and the plant leaves and also evaporates from the uh from the plant leaves itself. So these are the three sources of water loss so to speak. Two of them are lost for good and the third one the one that seeps through the ground, will be stored at least in the near surface that as to be like new surface ground water.

INT: But various people have said at the National Geog¬raphic and people in the water Freshwater In¬stitutes and would say all the fresh water that's ever existed on the earth still exists now in some form and uh and how is that it's it's hard to get over the idea that we have this amount of fresh water and the the amount never really changes.

FE: The amount never really changes because you have some of the water goes back into the ground, and the rest of it evaporates. What evaporates goes in the upper atmosphere and cools off and it forms clouds and it rains so that water comes right back towards earth. And it is a continuous flow this way, so we say the world is nearly 80 percent ocean so much of that rain water falls over the ocean anyway, but you say yes but the oceans also are the the places where there's a great deal of evaporation and the water that comes from the ocean leaves the salt behind, so we have a much higher percentage of water contribution to the clouds and rains from the ocean. So there is a continous flow because of the nearly continuous flow of energy from the sun. So that's the cycle meaning.
INT: I don't know if that's a that's the explanation you want of the hydrologic cycle.
WOMAN'S VOICE: It's a perfectly good one. I'm wondering if it's possible just to do it as if Alex were an eight-year-old child. And you wanted to really have him understand how the hydrologic cycle works.
INT: Which has explain for Carolyn's daughter Hadley who is eight and is a very smart eight year old and uh would would get it.
WOMAN: ...hydrologic cycle works.
FE: okay. See the hydrologic cycle works this way. You have an amount of water on the surface and some of it below the surface in the ground. The ground water stays there. The water on the surface much of it evaporates and as it evaporates it goes higher and higher an higher in the atmosphere and as it goes higher it gets colder and colder and colder because the atmosphere as you go up in the air you get colder. And as it gets to a specific level when it is cold enough it will form beads of water which is which are the clouds. And then it will rain meaning it will come back towards earth. Now the earth is nearly between seventy five and eighty percent of water in the ocean. So much of that rain would actually fallon the ocean. But the ocean is also the source of water evaporating leaving the salts behind in the ocean because the water that evaporates from the heat of the sun is clean fresh water that leaves all of the salts be¬hind. So that water goes up and up in atmosphere and forms the clouds and it rains again. So it it comes to the the land and the surface it goes back into the air forms clouds it rains it goes back into the land and surface it evaporates and so on and keeps making that continuous cycle so basical¬ly the fresh water amount on earth remains the same only because it goes on continuously evaporating and coming back as rain evaporating coming back as rain.

INT: Now some of the some of the people who uh are against uh using uh water resources say but things are different now because what we're doing to water is uh contaminating it in a way that's very difficult for for uh uh the cycle to uh to deal with so this water is not uh not cleaned properly it's contaminated in a way that it hasn't been. Are there are are we doing things to water in mod¬ern times that uh that are dangerous and different from what has happened to water in the past?

FE: Not in terms of the hydrologic cycle. Because the energy from the sun as it af-hits water and the water evaporates the water goes up there leaving everything behind. So not as far as hydrologic cycle we cannot poison the hydrologic cycle what certainly we can poison the bodies of water. For the fish or for humans or whatever it is by intro¬ducing things that are causes like lead mercury vernatium "and nu-uh and radioactive elements all of these things that are no good for humans or or or fish or plants. So definitely the things that we introduce into the environment uh can affect water bodies very badly. But they cannot affect the water cycle because as water leaves the earth to eva-uh into in the form of vapor, it goes out there clean water.

INT: Okay I'm just gonna stop here for a sec-(break) 'Kay restarting this interview again. Um, this is the question about the quantity of of water be¬cause you said in the earlier interview uh that uh the surprise to you in searching for water is that everywhere you look whenever you look there is more ground water than you expected. It is more plentiful resource than you had thought.

FE: It is really always surprising to me. Uh to think about water in the middle of desert areas and then think about it from the scientific point of view and then find out that there is actually more water than what our signs would tend to imply there is. In every oasis in the Western desert there had been a scare of overpumping and there-fore this water would run out and this and this and that and then they go and drive a few wells a little deeper or a little farther from where they are, and they find additional resource. In every¬where we we looked in in Somalia in Sudan in the Sinai about areas where there has never been any water that is known and there has never been any drilling and we sink wells and the first one brings in water. And we would when we sink wells we would say at least it's test well at least we know the stratigraph what do the layers down there look like how thick are they and SQ on. That the first well, nothing say it's gonna bring water but we will at least know what the strata fissure be¬low the surface is like. And then the well brings water. So I have been personally amazed at the amount of water that is there and whenever we drill or whatever we thought that there may be water there there would be. I shouldn't say that this is uh nationwide or everywhere in the world because there are many dry wells that have been driven. But at least the scientifically chosen locations for where you drill say in a fracture zone in intersecting fractures and so on that that area visible and known water exists. So I have been personally amazed at the amount of water there is in the places where we actually look and thought about it from the scientific point of view.

INT: Uh however much water there is some people worry that we are are poisoning the water for our chil¬dren's generation.
FE: Yes, no matter how much water there is it's certainly should be used sparingly because no mat¬ter how much water you should think about it as an a resource to be used not only by you but if it is not going to be replenished then it will be used by your children and grandchildren and therefore it should not be squandered. No question about it. And used very sparingly. But in cases where water is essential for. a country or is essential for food security or is essential for feeding people that otherwise would go hungry then utilize it, use the least possible amount, but utilize it for food production.

INT: I guess I always thought that eventually any well would run dry. But we see a well like this well in Notrun which has been bringing up water uh since the fourth century the same well.
FE: Uh, this well has been running consistently because it has not really been overpumped. I should say that every well would run dry if you overtax it if you pump more than its capacity. So you can run anywhere in the world no matter how huge the aquifer that's around it you can increase the pumping rates enough for it to completely run dry because you will just suck out all the water from from the layer around it would, would would would run dry for a while at least until some water from nearby locations would come to fill the voids that this water left, so you can run any well dry if you overutilize it or overpump it or over utilize its capacity. If you know the capacity of the well and the capacity of either the aquifer horizontal layer from which you're pumping or the fracture zone from which you're pumping, wells would would would would continue to supply until the stored supply in the ground is completely done.

INT: Let me ask you another basic science, a question a research question. Uh since you can't really see beneath the surface even with your your X-rays you only see to the to the r-to the rock in and then only in these very uh uh dry desert desert condi¬tions. How do you know when you're when you're drilling underneath the water how do you know how big an aquifer is how do you know that one well is connected to another well. Are they all connected somehow underneath the ground?

FE: Drilling usually occurs until the uppermost layer that you can utilize for the purposes you need. For instance you drill and if you find enough water for the amount that you need only at a hun¬dred meters you stop. Even if there's more water there's better water a about a thou-uh two-three hundred meters below. Nobody really drills higher because the drilling costs itself in addition to the pumping cost. Most of these waters are not do not have enough pressure to come out to the sur¬face of the ground on their own pressure. So they have to pump it out and pumping costs that expen¬are expensive high because you're using oil on motors to pump the water out. So that's gone. So you only really drill to the level where you have enough water to live by for your use. Now some of these layers or lenses of water are connected horizontally, some of them are connected vertical¬ly and we now believe that most of them are really connected through a very intricate system of frac-tures and joints and so on except for a few cases where there may be faults or fractures that are completely and totally nonporous, so they would separate rock from one place to the next. Totally and therefore would not allow water or fluids or gases to go through.

INT: Wonder if there's a question that we should ask about the Nile that we haven't asked? Know how to put that into question form but uh okay...
FE: Uh the ancient Egyptians were uh very good bureaucrats when it came to water. It was very significant it was their livelihood it was the most important thing in their uh life. They wanted to protect uh the Nile and the water vehemently for an ancient Egyptian uh to be received by the gods after death every individual had to say three things: I never killed a person, I never cut a tree, I never polluted the river. So these are the things if you can say these things then you can meet the gods if you can't you won't meet the dogs after in the afterlife. So the protection of the Nile and not polluting it became a very sig¬nificant aspect because it was really their lifeblood. As Urotogus said, the first tourist that came to Egypt about 2,500 years ago, he said, that Egypt is the gift of the Nile and it really is. Because if there was no Nile here it would all be desert and no one could live. And uh so they really knew that this is their livelihoods and that had to be protected and it's ups and downs became a very significant event in their uh lives and the amount of water became the controlling factor of uh of taxes and uh therefore most of the of the uh condition of the state became tied to the Nile itself so they knew what it levels are and they knew how much water came through and they were able to utilize it to the best of their abilities to make it to allow them to develop their civilization.

INT: The m-the Ni-the Nile is managed now by uh a group of countries uh acting together there's also an Egyptian uh authority which uh manages uh Egypt's part of the part of the Nile I'm sure there's a Cairo Nile Authority to to manage. Uh how do you think the river how would you say the river is being managed today is it wisely handled or...
FE: Uh, there are Nine uh, there are nine countries that utilize water of the of the Nile. And these Nile uh countries or the Nile Basin Countries nine of them have formed this...committee and uh that committee looks into the utilization of Nile water from the source all the way to the mouth of the river. I think there has been a quite a good plan for how to use the river and quite reasonable cooperative agreements between these uh countries of who uses how much because they need how much water and there is a kind of a a friendly rela¬tionship between these uh counties and the or the when the uh the uh Aswan Dam was being built there was a need to additional to add uh uh agreements to how much water should Egypt use and how much water should the Sudan use at that uh water from the uh from the Nile from behind the dam and therefore there is I believe that most of the water of the Nile is being well managed and well used.
INT: Okay. There's a a uh a question that Carolyn has written down here. Which is a little foreboding. Uh, uh and I don't know if you uh if you can I don't know what I would say question but she she wants you to talk about uh philosophical thoughts uh uh concerning man and water and the and the earth. Man and earth. And having seen such mag¬nificent performance of woman and the earth yes¬terday afternoon I I leave you to carryon.
WOMAN'S VOICE: Well you won this very prestigious award for just your ....
INT: For your ability to express your thoughts.
FE:. (Laugh) There is no question that uh water must be the most significant thing on anybody's mind. Because our bodies are made mostly of water we live off what we eat from the earth that could not be without water and the clouds shade us in during hot times or hot days the water that comes into rivers feeds us with fish and all kinds of things. The water in the ocean provides all kinds of food potential. The water dissolves things and accumu¬lates things and concentrates them for us to use. Or else would not be able to have salt mines for instance and that is all done by water. Water purifies things water changes the chemistry of things water combines with things it is the most malleable uh compound in nature. It is certainly one of the things that has come to us or has it is certainly one of the things that is talked about in religion. It is said that uh the Prophet Muham¬mad once said that The end of the world is not going to come until the land of the Arabs goes back to be covered by lakes and rivers. This means that this man only 14 hundred years ago, actually knew from word of mouth that uh Arabia used to be covered by lakes and there were many rivers there. Meaning that after a very long time the end of the world is not gonna come after many many thousands of years the way the earth used to be or this the land of ours used to be way back then. So if they the the existence of water in places where water does not exist even today has even been ingrained in the mind of humanity. What water is what ice is and what does it go and how how much ...water has certainly shaped our thinkings and is part of our consciousness. And uh when I think about Egypt and think about the drought that actually forced people to leave the desert and populate an area that's already populated along the banks of the river, then you think about water moving lnto the channel of the river as the place on which civi¬lization began in Egypt. So you can just think how water was a critical factor in shaping human his¬tory and in shaping even shaping the human mind and the way we think about things and the way we approach uh uh the problems in life and the way we have we are think about the future potential of human beings that where would w-w-w-we be many yaers from today when I first started to think about the deserts of Egypt, I think about them in terms of places that are now yellow hot miserable and deserted. but the way I think about them in the future as places that are green inhabited, utilized from the use of ground water. So it can even change my perception about a country or a whole people. So certainly it's been something that that sits very deep into human consciousness and whether we think about it or not it his there that is affecting our thoughts and affecting our actions. Is that sort of good enough?

INT: (Laughs)
FE: Is it?
WOMAN: Yes. Perfect.
INT: What happened uh uh what happened yesterday afternoon and I I let me just tell our listeners I won't I won't uh I won't actually say this on net¬on the tape but uh it is possible for uh uh for you to be surprised by what uh what water does be¬cause this this out of nowhere this storm uh uh appeared yesterday and was very dramatic. What what happened there?
FE: or the sand storm or the dust storm. The whole thing.
INT: The whole thing.

FE: Yeah. That was an incredibly uh unique condition. Nothing like that ever happened I have never seen the sequence of event yeah, I have never seen the sequence of events happen the way we saw them in in this one. The very first thing that I I saw and recognized is in the distance, before anybody really noticed that there was a huge cloud of dust that came in from a front of uh wind front that picked up the fine grain material way out there, not where we were standing but way out there in a front moving down the slope and then some of the a-some of the dust was picked up high in the at¬mosphere making a couple of mushroom uh shapes. Well this is a dust storm a little more than usual but but's okay I've seen dust storms in the in the past in this part of uh the desert. But that was followed instantaneously by a weird rain storm where the black cloud came from nowhere and it started to rain of course it was not a very huge deluge of rain but enough to be unusual in this kind of setting at that kind of time of the year. And in this particular area anyway no no rain ever occurs in in the month of May. The most unusual thing is that after the rain or some of the rain occurred then the wind picked up even more and then the sandstorm began, actually when rain oc¬curs it stabilizes the soil a little bit because it gets the soil wet and it it aglumerates so it actually makes a a wet soil that protects every¬thing below. But apparently that has been so much uh work in this uh region where there is a little bit of uh plantation and there is a great deal of car movement over this land that's on to expose much of the fine grain material to the actual wind and therefore this very strong wind was able to pick up uh sand and the sand was flying maybe two to three meters high because it's covering us all completely and totally and so you're really con¬fronted by this uh curtain of sand that moves towards us and it kept on increasing and increas¬ing, consistently and constantly after the rainstorm, so that's a very unusual thing that you're you're actually very lucky to see this even in the desert very few people have seen a real honest to god sandstorm "and this was one honest to god sandstorm. And sand began to accumulate around uh the jeeps it began to accumulate around the drill for ground water so there was a great deal of of movement...because that was a very unusual event in the terms of the amount of particulate material that was moved. Particularly since it be¬gan with a¿ a gentle rather usual dust storm and then came the uh clouds with a great deal of uh rain followed by the uh sandstorm followed by thunder and it actually rained again so this se¬quence of events I had never seen in the desert before. So it was a very unusual event.

INT: I just I'll just ask one more question that we might use uh put in somewhere uh uh you know a great deal about the history of of uh uh the earth geologically and you've you have used uh uh uh all that you learned in uh in uh flights to the moon and putting men in space to to to better un¬derstand uh the Earth, uh I wonder if you are able to uh uh better than than uh than than other people to predict the future uh as regards water to say what you expect will happen with water on earth?
FE: There is no question in my mind that uh water will be needed in the future more than it is needed today because of the increase of population worldwide and the expectation of better foods for everybody in the future. And if you want to in¬crease food production worldwide you need more water resources, so there is really no question in my mind that the the demand for water is going to increase. If all of the river systems are being utilized to the hilt I mean to their utmost capac¬ity there is no other source for water for agri¬culture except ground water because these are ini¬tial plans can provide water economically for drinking purposes and human use. But they really would not be economical at all to produce uh water for agricultural purposes or else they cost the cost would be prohibitive. So we have to depend on ground water. And therefore if we are going to need to increase the ground water utilizing agri¬culture in the future considerably, maybe we should look for additional resources today. Geo¬logical evidence says there is more water than we used to believe we geologists used to believe and therefore we should look at ground water through a whole new perspective maybe new glasses to look and s-at some new ideas and uh better vision of where that water might be because we should be better prepared in the future for the need to use more water than we are using today.

INT: Do you think there is a finite identifiable amount of water on earth that that we can economically use that we can get to?
FE: There's no way of telling. Because also it really depends on where you are.
INT: Hmm.
FE: And h-where it is. Because all of this that uh every every meter means some money so it's not uh, there is no way.
INT: Well, Miss Jensen has raised her hand (break)
FE: All of the dry places on earth, the deserts and the semiarid zones are created in exactly the same way. These places used to host kinder climates and they used to host more surface water than they there is there today. And when the climaftic con¬ditions change the wind began to reshape the sedi¬ments into the shape of dunes so the dunes of Yuma Arizona or South of Salton Sea, Calif., are identical in formation in history in genesis to the dunes in Egypt. The only difference between these types of places are the conditions of climate today how dry is it and the conditions of subrace cover in some parts of Egypt there may be absolutely no surface cover whatsoever. In Death Valley or in Southern California you have all kinds of uh of uh vegetation cover because there is more moisture and because there is uh there is verge-there there uh enough rain so that vegeta¬tion grows. So the distinction between the two is only really in these forms. As far as the nature of the how it originated and how it evolved in space and in time it's exactly the same. And this is very good for us as geologists, because whatever we can get on information or knowledge from one place we can apply to the other and that is really was the driver behind my need to go and visit not only the American Southwest but all of the deserts of the world in China and in India and Australia and Arabia all of North Africa the I never really was able to begin to understand the desert of Egypt until I fully understood these other deserts and tried to make relations between all of them. Good?


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