1 00:00:00,020 --> 00:00:04,080 2 00:00:04,100 --> 00:00:08,200 3 00:00:08,220 --> 00:00:12,290 Flooding is the most common 4 00:00:12,310 --> 00:00:17,360 and most costly natural disaster in the country. 5 00:00:17,380 --> 00:00:20,400 In the last two years, more than 8.5 billion in damages 6 00:00:20,420 --> 00:00:24,440 7 00:00:24,460 --> 00:00:28,460 more than 130 lives lost 8 00:00:28,480 --> 00:00:32,480 How many are there of you? - There's about 40 9 00:00:32,500 --> 00:00:35,510 In the bus? 10 00:00:35,530 --> 00:00:40,560 The question, is what can we do to mitigate this destruction? 11 00:00:40,580 --> 00:00:46,600 12 00:00:46,620 --> 00:00:49,290 a FIRM, as they call it, a Flood Insurance Rate Map 13 00:00:49,310 --> 00:00:52,950 is a panel which depicts flood zones 14 00:00:52,970 --> 00:00:56,330 and these flood zones give an idea of specific risk. 15 00:00:56,350 --> 00:01:00,870 How likely you may or may not be to encounter a flooding event within a given period of time 16 00:01:00,890 --> 00:01:04,190 These maps need to be updated because the factors upon which 17 00:01:04,210 --> 00:01:07,530 the engineering is based change over time. 18 00:01:07,550 --> 00:01:11,660 You have changes in the composition of the ground material, 19 00:01:11,680 --> 00:01:17,980 you may have an increase in the impervious area. You may have better flood study methods available. 20 00:01:18,000 --> 00:01:21,080 One of the ways to keep 21 00:01:21,100 --> 00:01:25,160 these FEMA maps up to date is by tracking urban change 22 00:01:25,180 --> 00:01:30,210 using satellite imagery. Take this suburb of Atlanta, Georgia 23 00:01:30,230 --> 00:01:33,250 If we look at Landsat images spanning a 27 year period 24 00:01:33,270 --> 00:01:37,310 we can pinpoint areas of the earth's surface that have changed. 25 00:01:37,330 --> 00:01:41,340 usually because of construction. Like here, 26 00:01:41,360 --> 00:01:45,370 where the Mall of Georgia was built. 27 00:01:45,390 --> 00:01:49,390 A product called NUCI help to mine these images. 28 00:01:49,410 --> 00:01:53,420 Well, NUCI is especially important when considering risk, 29 00:01:53,440 --> 00:01:57,440 because it allows us to identify trends in urbanization. 30 00:01:57,460 --> 00:02:01,490 Now if you identify areas where urban change is accelerating, there are consequences. 31 00:02:01,510 --> 00:02:05,560 That increase in impervious area are going to mean altered flood characteristics 32 00:02:05,580 --> 00:02:09,630 likely, and increased risk, because people are probably building houses there. 33 00:02:09,650 --> 00:02:13,670 Impervious area essentially means ground cover which has been changed 34 00:02:13,690 --> 00:02:17,730 from the natural state to, say, a paved area, which is going to be concrete or asphalt. 35 00:02:17,750 --> 00:02:21,770 The infiltration characteristics of that ground material 36 00:02:21,790 --> 00:02:25,830 have been altered significantly, such that the ground is no longer able to hold water 37 00:02:25,850 --> 00:02:29,870 which means that local flooding sources are going to receive more water 38 00:02:29,890 --> 00:02:33,890 and the flooding characteristics are going to change. 39 00:02:33,910 --> 00:02:37,970 Tracking urban change from space helps everyday people 40 00:02:37,990 --> 00:02:42,040 understand their flood risk, and take action 41 00:02:42,060 --> 00:02:46,100 You can't see them, or hear them, but since 1972 42 00:02:46,120 --> 00:02:50,200 Landsat satellites have been sending us data 43 00:02:50,220 --> 00:02:56,250 and today, that data helps us manage the high cost of flooding here on earth. 44 00:02:56,270 --> 00:02:58,290 45 00:02:58,310 --> 00:03:02,320 46 00:03:02,340 --> 00:03:04,865