is a part of that same area. This revealed that this pink colored area contained a crop that had not been identified previously. It is a new crop in the Imperial Valley. It is an elysian grass that is being grow. for the first time this year in that valley. It is a hay crop harvested in the late winter, in December. This, then, illustrates the fact that the land use analysis was right, that a new crop was identified and in fact now becomes a part of the crop inventory in that area.

The CHAIRMAN. What are the deep red areas; what crop is that? Mr. MATHEWS. Well, these are probably something like alfalfa fieldor possibly sorghum. I am not quite sure what the detailed identifications are in all cases. The grays are generally fields that are fallow fields and the darkest grays are ones that are the most moist, for example. Senator GOLDWATER. I might say you are looking at Utah's and Arizona's water. [Laughter.]

The CHAIRMAN. The results of it.

Mr. MATHEWS. I will turn to some of the water aspects in just a moment.

Next slide, please.

I will talk about geology a little bit first.

Figure 353 is a map of Alaska and part of Canada. The lower part of the chart is a similar map on a slightly smaller scale.

GEOLOGICAL ANALYSIS

Now, prior to ERTS, these major faults had been identified. They had been identified by Nimbus space photography, but also they had been identified to a limited extent by land surveys, although this is a generally remote area. With the analysis of the topography and these outlines, the geological analysis indicated that they were likely mineral deposits of the nature shown up here.

The ERTS images, which show information in more detail than Nimbus, established the location of these crustal fractures that you see running more or less at right angles to the major fault lines. What has resulted is that a new geologic map has been made that now iden tifies in a more pinpoint fashion where the likely sources of these minerals are, that being generally at the intersections of these major fault lines and lineaments. So, instead of having to investigate very large areas, it serves to narrow down the areas where the possible mineralization does in fact occur.

This has also been done up in the north bank in terms of looking at geological configurations and Dr. Fletcher referred to identification of areas of high potential for oil that had not been known before.

The CHAIRMAN. I suggest you might slide the map around on the end of the table and then you can talk more directly into the microphone. We can hear you most of the time but sometimes it fades away when you turn and look directly at the screen.

Mr. MATHEWs. For instance, over in Africa, similar geological mapping has taken place in remote areas that has identified very similar features which now allow the new areas to be investigated with much higher confidence.

Let's get to the water part. Next slide, please.

Figure 354 contains two images of a river system in Iowa that pro

WATER RESOURCES ANALYSIS

duced a severe flooding condition in this particular area. It is the Nishnabotna River system. These ERTS images were taken before, on the left, and after, on the right, the flood. The Missouri River is the wide feature cutting across the lower right corner of the images. Under normal conditions, the vegetation is so dense that you would hardly see the Nishnabotna River. But during the flooding conditions these areas were flooded as indicated in the image on the right by the darker area, even though at the time the picture was taken, it was 5 days after the flood had really crested and dissipated. However, the damage to the vegetation and other features very carefully outlines the flooded area over the entire west and east Nishnabotna system.

I might mention that this was also looked at with aircraft, but certain parts were missed or were surveyed at the wrong time in terms of the flooding condition. It has been established that the ERTS image on the right very accurately outlines the flood.

Now, what good is this? Well, this allows assessment of the total damage for use in possible litigation. In terms of insurance claims, insurance companies can establish what the nature of their overall problem might be. The Federal Government in terms of compensation can establish what the nature of their problem might be and also what the effect of the crop production in these bottom lands might be since the bottom lands there are heavily cultivated.

The next chart (fig. 355) depicts a different application with respect to water resources. Now, this happens to be an area near Lubbock in western Texas and these are computer derived images from ERTS that

FIGURE 355

show only water. Here you can see an almost starlike constellation of markings that go down to smaller and smaller water areas.

Now, these water areas are known as playa lakes and they feed the underground water supplies. They come and go with extreme rapidity and the ability to really use underground water or surface water for irrigation is very much dependent on whether these lakes are full or

not.

Actually in one ERTS image there were over 6,600 of these particular lakes that were counted and water areas determined.

Now, the next image (fig. 356) shows the same area about a month later, and many of these small playa lakes have in fact disappeared.

The last slide (fig. 357) shows the analysis of actual water area changes between the 9th of October, the 14th of November, and the