61 



A very important research project in the actual use of 

 water. 



For example, one of the things that the farmers did 

 was to have a ditch so low that unless it was very full they 

 couldn't get any water out of it. Things like that. The 

 problem was to raise the watercourse so that, in fact, the 

 water would flow from it into the field. Very, very simple 

 things, but very critical. And I know it was one of the 

 research outcomes. 



Another one was the building of the Tarbela Dam. Ayub 

 Khan and the Pakistanis in general were very anxious to do 

 this. There wasn't any money to do it in the basin 

 settlement plan, which the bank was really basically 

 responsible for financing. There had to be extra money, and 

 where was the extra money going to come from? It was 

 eventually, I guess, a loan to the Pakistani government. It 

 was a big project, a billion, $2 billion project. The 

 biggest -dam in the world, the biggest earth-filled dam in 

 the world, about 400 feet high and about two miles long. It 

 only holds about 10 million acre feet of water, compared to, 

 say. Hoover Dam which holds 80 million acre feet of water, 

 just because of what I spoke about yesterday, the geology of 

 the country. 



They had a lot of trouble with it. The main trouble 

 is that the flow of the Indus at that point is about 90 

 million acre feet it per year, and they can store 

 essentially only 10 percent of that water. The other 90 

 percent has to go over the spillway. The spillway is 

 essentially the Indus River. There's very little difference 

 between the river and the spillway. Of course, the spillway 

 is at the top of the dam, that's the nature of dams, that 

 you have to build a spillway so you can fill the dam. 

 Otherwise you couldn't fill the dam. But you can't have the 

 spillway at the level of the dam or else it will flow over 

 the whole dam. 



But the water flowed down that spillway at ninety 



miles an hour, so it was an incredible sight to see it. It 



dropped then a couple of hundred feet in this huge waterfall 



into the river valley underneath. The force of the water 



and the volume of the water eroded and undercut the bottom, 



so they had to build a new spillway and a new base for it, 



pouring couple of million tons of concrete at the base of 

 the spillway. 



Sharp: Just to keep the dam intact. 



Reveller To keep it intact. 



The other problem was that the bottom of the dam 

 leaked, so they were getting water under the dam, coming out 

 on the lower side. They had to put in what they call relief 

 wells so that they could control that water. Then they put 

 thousands and thousands of tons of clay on the bottom of the 

 lake to try to stop the leaks. They eventually did fairly 

 well with that. Otherwise, again, the dam would have 

 eventually destroyed itself by undercutting. 



