30 OCEANOGRAPHY IN THE UNITED STATES 



Fla., which consisted of sending a crew down there and measuring the 

 impoundment of sand behind a jetty and measuring tlie waves care- 

 fully during the period. We finally got it at Anaheim Bay — got 

 a set of even higher wave actions and sand movement at Anaheim Bay. 



We were grateful to find that we were able to make some kind of 

 pattern through these points and we think we are now about ready to 

 firm up this relationship of wave energy and the movement along the 

 shore. 



We are glad to see that we are finally making a little sense out of it. 



The next slide. The rate of movement of the sand along the shore 

 frequently tends to cause an inlet to migrate. This shows the history 

 of Rockaway Inlet, Long Island Sound, since about 1935. This shows 

 its progressive position. It has averaged moving about 250 feet a year 

 for the past 100 years so it has made quite a large migration here in 

 this historical period. 



It was finally fixed in position here by the construction of this jetty. 



These inlets as they are crowded by the migration begin to erode on 

 the other side. 



The next slide. We found out that if we set up an inlet in one of 

 our test basins — and this happened to be a basin we rented at the 

 Waterways Experiment Station — and if we put a deep bay in here and 

 put in the wave action we could cause this inlet to begin to migrate. 



We found, liowever, that the inlet always had the ability even when 

 it was sealed that it would break out again. It would seal and then 

 break out again and always remained open. We were never able to 

 form a very heavy bar out in this area. We began to suspect that 

 that was because we had such a deep lagoon so we changed the con- 

 ditions and, instead of having a 100-foot deep lagoon, we used about 

 a 20-foot depth. 



We repeated these conditions and found out that with the shallow 

 lagoon we were just about able to seal it off. 



You notice this lieavy bar as it moves in here and begins to seal off 

 this inlet. After it forced the migration tliis far, we decided to see if 

 we could break through the bar which we did by generating an artificial 

 storm on the particular basin. 



The next slide shows some of the studies we made on superelevation 

 of the water level or rise in the water level due to the tsunamis. 

 Tsunami is the Japanese term for a wave generated by a submarine 

 earthquake. We studied the runup of such waves on the shore; the 

 results had immediate application in Hawaii. 



Another is the "Quadratic Bottom Stress Fornmla." That means 

 if you have a surface flow into the bay due to wind, the bottom water 

 is trying to drain out in the other direction so that the normal laws of 

 water flow in the river do not hold because here you have a different 

 flow direction on the top and bottom. 



"Wave Runup on Permeable and Impermeable Slopes," to find out 

 how we need to build a levee or seawall. 



The next slide. These are some of the results we have had here on 

 Lake Okeechobee. We were requested to cooperate in the study down 

 in Lake Okeechobee to find out about the liurricane winds over the 

 lake. You can see these successive hours. The hurricane came out 

 of the southeast and moved across this corner of the lake. The winds 

 were first out of the north. Tliey started piling the water up in the 

 southeast corner of the lake and finally had dried out the top part of 



