1 00:00:00,600 --> 00:00:01,735 [bright electronic music] 2 00:00:01,768 --> 00:00:04,237 >> Announcer: NASA's Jet Propulsion Laboratory presents 3 00:00:04,270 --> 00:00:06,239 the von Karman Lecture, a series 4 00:00:06,272 --> 00:00:08,474 of talks by scientists and engineers 5 00:00:08,507 --> 00:00:12,311 who are exploring our planet, our solar system, 6 00:00:12,344 --> 00:00:14,414 and all that lies beyond. 7 00:00:26,792 --> 00:00:30,496 >> Good evening, everybody, how is everyone tonight? 8 00:00:30,529 --> 00:00:31,931 Excellent, good, that's what we like to hear. 9 00:00:31,964 --> 00:00:33,833 Hope you all like the new chairs 10 00:00:33,866 --> 00:00:36,436 [chuckles] so anyway, shall we? 11 00:00:36,469 --> 00:00:40,239 Among the U.S. states, California is atypical in that it has 12 00:00:40,272 --> 00:00:43,576 both highly variable annual precipitation 13 00:00:43,609 --> 00:00:46,446 as well as a great disparity between 14 00:00:46,479 --> 00:00:48,815 where and when the precipitation falls. 15 00:00:48,848 --> 00:00:51,217 To deal with this, California has a vast array 16 00:00:51,250 --> 00:00:53,820 of infrastructure in place to store and move water 17 00:00:53,853 --> 00:00:56,589 throughout the state, much of which also serves 18 00:00:56,622 --> 00:00:58,691 to protect against flooding. 19 00:00:58,724 --> 00:01:00,960 Monitoring and maintaining this infrastructure 20 00:01:00,993 --> 00:01:04,097 is both critical and an enormous undertaking 21 00:01:04,130 --> 00:01:07,266 involving local, state, and federal resources. 22 00:01:07,299 --> 00:01:09,068 Today, most of the monitoring is done 23 00:01:09,101 --> 00:01:12,772 through visual inspection from motor vehicles or on foot, 24 00:01:12,805 --> 00:01:14,907 but researchers at JPL are working to change 25 00:01:14,940 --> 00:01:17,743 that by employing airborne radar techniques 26 00:01:17,776 --> 00:01:20,713 originally developed for earth science. 27 00:01:20,746 --> 00:01:23,549 Tonight's talk will tell us how it's done. 28 00:01:23,582 --> 00:01:25,218 Our guest tonight is a radar scientist 29 00:01:25,251 --> 00:01:27,987 at NASA's Jet Propulsion Laboratory where her main research 30 00:01:28,020 --> 00:01:30,656 is focused on applying radar remote-sensing 31 00:01:30,689 --> 00:01:32,692 to a variety of hazards. 32 00:01:32,725 --> 00:01:35,795 Her work includes developing methods to identify threats 33 00:01:35,828 --> 00:01:39,298 to levees, dams, and aqueducts, measuring subsidence 34 00:01:39,331 --> 00:01:42,835 in New Orleans, tracking and characterizing oil spills, 35 00:01:42,868 --> 00:01:46,472 and identifying ways in which the 2010 Gulf oil spill 36 00:01:46,505 --> 00:01:49,842 impacted land loss in coastal Louisiana. 37 00:01:49,875 --> 00:01:51,644 She has been working in the radar science 38 00:01:51,677 --> 00:01:55,348 and engineering section at JPL since 2004 39 00:01:55,381 --> 00:01:57,683 and currently is a member of the NASA-ISRO 40 00:01:57,716 --> 00:02:01,320 Synthetic Aperture Radar mission Science Definition Team 41 00:02:01,353 --> 00:02:03,923 leading the application's subgroup. 42 00:02:03,956 --> 00:02:05,825 Ladies and gentlemen, please help me welcome 43 00:02:05,858 --> 00:02:08,561 tonight's guest Dr. Cathleen Jones. 44 00:02:08,594 --> 00:02:11,764 [audience applauding] 45 00:02:17,369 --> 00:02:18,204 >> So 46 00:02:19,605 --> 00:02:22,441 I have to admit that when I was asked to give this lecture, 47 00:02:22,474 --> 00:02:24,911 I was really concerned because I know 48 00:02:24,944 --> 00:02:28,814 that the standard for these lectures is really high 49 00:02:28,847 --> 00:02:31,450 and I don't have any snazzy videos 50 00:02:31,483 --> 00:02:36,155 of Mars rovers or beautiful pictures of the moons 51 00:02:36,188 --> 00:02:40,360 but anyway, I think I have an interesting story to tell 52 00:02:41,527 --> 00:02:45,198 and you might enjoy it, so NASA does a lot 53 00:02:45,231 --> 00:02:48,334 of earth science and part of what they do 54 00:02:48,367 --> 00:02:52,004 is applications of earth science, so figuring out how 55 00:02:52,037 --> 00:02:56,509 to use the techniques that are developed in order to benefit 56 00:02:56,542 --> 00:03:00,613 society in some way and what I'm gonna to talk to you today 57 00:03:00,646 --> 00:03:03,249 is about water and what goes on 58 00:03:04,683 --> 00:03:07,220 whenever there's too much of it or too little of it. 59 00:03:07,253 --> 00:03:09,956 The title of my talk is Sink or Swim? 60 00:03:09,989 --> 00:03:13,726 Using radar to protect California's water supply 61 00:03:13,759 --> 00:03:16,696 and that's kind of a very, actually, 62 00:03:16,729 --> 00:03:18,998 what I do is a little less than that. 63 00:03:19,031 --> 00:03:22,668 I don't use radar directly to protect the water supply 64 00:03:22,701 --> 00:03:26,372 but what I use radar to do is to see things 65 00:03:26,405 --> 00:03:29,008 that are indicative of the health of the levees 66 00:03:29,041 --> 00:03:31,110 and aqueducts and I'm gonna explain to you 67 00:03:31,143 --> 00:03:32,812 how I do that today. 68 00:03:34,113 --> 00:03:36,382 Our testbed for developing these techniques 69 00:03:36,415 --> 00:03:38,918 is here in California and I work a lot 70 00:03:38,951 --> 00:03:43,923 with the California Department of Water Resources for this. 71 00:03:43,956 --> 00:03:47,593 So when people think of California, 72 00:03:47,626 --> 00:03:50,396 maybe they think about its natural beauty 73 00:03:50,429 --> 00:03:52,865 or they think about the theme parks. 74 00:03:52,898 --> 00:03:55,268 They almost always think about Hollywood 75 00:03:55,301 --> 00:03:59,439 and maybe that leads them to think of NASA or even JPL 76 00:04:00,639 --> 00:04:03,809 or the Mars program but I'm here to tell you 77 00:04:03,842 --> 00:04:06,812 that that's not what you should be thinking of 78 00:04:06,845 --> 00:04:10,116 whenever you think of California. 79 00:04:10,149 --> 00:04:13,486 California is all about the water, okay? 80 00:04:15,054 --> 00:04:18,958 There's one saying that exemplifies California. 81 00:04:18,991 --> 00:04:23,162 It's whiskey's for drinking and water's for fighting 82 00:04:23,195 --> 00:04:27,166 and believe me, that defines California. 83 00:04:27,199 --> 00:04:29,669 The history of California is one 84 00:04:29,702 --> 00:04:33,039 of amazing technical achievements 85 00:04:33,072 --> 00:04:36,909 and incredible political machinations 86 00:04:36,942 --> 00:04:40,446 in order to provide water for arid regions 87 00:04:41,780 --> 00:04:44,517 and just to show an example here, 88 00:04:46,285 --> 00:04:50,456 this is a Los Angeles aqueduct which was built in the 1910s 89 00:04:52,491 --> 00:04:55,528 in order to take water from the Owens Valley 90 00:04:55,561 --> 00:04:58,264 and supply it to Los Angeles. 91 00:04:58,297 --> 00:05:01,567 This actually engendered what is known in history 92 00:05:01,600 --> 00:05:06,372 as the Water Wars, there was a big conflict over this 93 00:05:06,405 --> 00:05:10,576 and pretty much, that's the history of water in California. 94 00:05:12,144 --> 00:05:15,315 It's contentious so what's the issues? 95 00:05:17,683 --> 00:05:19,618 Well, let's start with the weather, 96 00:05:19,651 --> 00:05:22,021 by considering California's weather. 97 00:05:22,054 --> 00:05:26,092 Well, California has floods; they have pretty epic floods. 98 00:05:26,125 --> 00:05:29,962 In 1862, there was a flood that extended from, 99 00:05:31,563 --> 00:05:34,767 it was in Oregon and extended all the way 100 00:05:34,800 --> 00:05:38,971 through Southern California; it went on for months. 101 00:05:41,340 --> 00:05:43,809 The entire Central Valley, 102 00:05:43,842 --> 00:05:46,512 300 miles long by 30 miles wide, 103 00:05:47,479 --> 00:05:50,383 was inundated for several months 104 00:05:50,416 --> 00:05:54,854 and people were rowing down K Street in Sacramento 105 00:05:54,887 --> 00:05:58,624 to get from one government building to another. 106 00:05:58,657 --> 00:06:02,194 So the reason that happens in California 107 00:06:02,227 --> 00:06:06,699 is because we get about 50% of our water 108 00:06:06,732 --> 00:06:10,202 through atmospheric river events, 109 00:06:10,235 --> 00:06:13,572 and so there's several atmospheric river events a year 110 00:06:13,605 --> 00:06:17,476 will provide the vast majority of the water in California, 111 00:06:17,509 --> 00:06:20,679 so this kinda shows what those events are. 112 00:06:20,712 --> 00:06:23,449 They're also called the Pineapple Express 113 00:06:23,482 --> 00:06:26,819 because they bring moisture from the tropics 114 00:06:26,852 --> 00:06:30,189 from here around Hawaii up to California 115 00:06:31,657 --> 00:06:35,027 and the West Coast of the United States. 116 00:06:35,060 --> 00:06:38,497 And when they're called atmospheric rivers, 117 00:06:38,530 --> 00:06:42,134 it's because they carry the equivalent of water 118 00:06:42,167 --> 00:06:45,805 of the Mississippi River or even sometimes more 119 00:06:45,838 --> 00:06:48,741 for the big events and they dump it 120 00:06:49,875 --> 00:06:52,645 on the mountain ranges in California 121 00:06:52,678 --> 00:06:54,847 and Oregon and Washington. 122 00:06:56,114 --> 00:06:58,951 So that becomes a source of floods 123 00:07:00,552 --> 00:07:04,457 whenever more than one happens in close proximity 124 00:07:04,490 --> 00:07:07,160 to each other and 1862 was epic, 125 00:07:08,760 --> 00:07:12,932 but 1997 and even this past year have had major floods 126 00:07:14,933 --> 00:07:19,638 in California but don't worry, we have droughts also. 127 00:07:19,671 --> 00:07:23,843 There's a very diverse history of weather in California. 128 00:07:26,111 --> 00:07:30,283 These spikes are floods and these troughs are droughts 129 00:07:32,217 --> 00:07:36,655 and we just have come out of a pretty severe drought. 130 00:07:36,688 --> 00:07:40,860 In 2016, about half of the state was in the highest category 131 00:07:42,427 --> 00:07:46,565 of drought, which I always thought that they probably had 132 00:07:46,598 --> 00:07:49,535 to invent this name in order to add a category 133 00:07:49,568 --> 00:07:51,804 because it's called exceptional drought. 134 00:07:51,837 --> 00:07:56,408 You'd already had extreme drought so that was taken 135 00:07:56,441 --> 00:07:59,579 but in 2016, only this very small part 136 00:08:02,214 --> 00:08:05,518 of California was not in drought 137 00:08:05,551 --> 00:08:08,187 and it was called abnormally dry 138 00:08:08,220 --> 00:08:10,556 so this this was a bad year. 139 00:08:12,758 --> 00:08:16,896 This is Central Valley where the exceptional drought area 140 00:08:16,929 --> 00:08:20,866 was and this is a farm in the Central Valley 141 00:08:20,899 --> 00:08:22,401 and a lot of farms 142 00:08:24,870 --> 00:08:27,039 were too dry to be planted 143 00:08:28,373 --> 00:08:31,644 because there weren't sufficient surface water deliveries 144 00:08:31,677 --> 00:08:34,446 because there just wasn't sufficient rainfall 145 00:08:34,479 --> 00:08:36,482 in California that year. 146 00:08:37,883 --> 00:08:40,753 But just because there's a drought one year doesn't mean 147 00:08:40,786 --> 00:08:43,255 there's not can be a flood to next year. 148 00:08:43,288 --> 00:08:47,460 California also has the most variable interannual rainfall 149 00:08:48,660 --> 00:08:51,864 of any of the states in the union, so this shows 150 00:08:51,897 --> 00:08:55,134 Lake Orville in 2005 during the drought 151 00:08:56,602 --> 00:09:00,005 and you can see how low the reservoir was 152 00:09:00,038 --> 00:09:03,776 but in 2017, 2015, two years later, in 2017, 153 00:09:07,813 --> 00:09:11,016 the reservoir was full, in fact, there was problems 154 00:09:11,049 --> 00:09:15,588 where the emergency spillway was actually came into use 155 00:09:15,621 --> 00:09:20,259 and they had to evacuate 188,000 people downriver 156 00:09:20,292 --> 00:09:24,697 from this one structure, so that variability 157 00:09:24,730 --> 00:09:27,800 is a problem also in the state. 158 00:09:27,833 --> 00:09:32,237 But the fundamental problem is that there's a great mismatch 159 00:09:32,270 --> 00:09:35,775 between where and when precipitation falls 160 00:09:36,642 --> 00:09:39,745 and where and when it's used. 161 00:09:39,778 --> 00:09:43,950 So this map shows that about 75% of this precipitation 162 00:09:45,784 --> 00:09:48,354 occurs in the upper third of the state 163 00:09:48,387 --> 00:09:52,191 but if you look at where people live, about, 164 00:09:52,224 --> 00:09:56,395 most of the people live in the bottom 2/3 of the state, 165 00:09:57,562 --> 00:10:00,065 in fact, 80% of the water usage occurs 166 00:10:00,098 --> 00:10:03,235 in the lower 2/3 of the state. 167 00:10:03,268 --> 00:10:05,537 And I just wanna point out several things 168 00:10:05,570 --> 00:10:07,239 about this map here. 169 00:10:08,507 --> 00:10:11,577 The low value here, this orange value 170 00:10:11,610 --> 00:10:14,747 is under five inches of precipitation a year. 171 00:10:14,780 --> 00:10:18,284 The high-value up here is above 120 inches 172 00:10:19,885 --> 00:10:23,722 of precipitation a year, so whenever somebody says 173 00:10:23,755 --> 00:10:26,225 it's exceptionally dry down here, 174 00:10:26,258 --> 00:10:28,694 I'm not really sure what they mean 175 00:10:28,727 --> 00:10:31,797 because [chuckles] it seems like it's normally 176 00:10:31,830 --> 00:10:35,901 exceptionally dry but really, droughts that occur 177 00:10:37,369 --> 00:10:41,273 in the northern and the central part of the state 178 00:10:41,306 --> 00:10:44,577 have a huge impact on the water supply. 179 00:10:46,178 --> 00:10:49,882 So, most of the water falls in winter 180 00:10:49,915 --> 00:10:53,719 and it's stored as snowpack in the mountains and water usage 181 00:10:53,752 --> 00:10:57,523 actually peaks in summer because of that agriculture use. 182 00:10:57,556 --> 00:11:01,727 Agriculture uses about between 70 and 80% of the water 183 00:11:03,295 --> 00:11:05,564 in the state of California. 184 00:11:06,865 --> 00:11:10,502 So the way that California deals with this 185 00:11:10,535 --> 00:11:13,472 is through capturing the water 186 00:11:13,505 --> 00:11:17,042 and conveying it around the state. 187 00:11:17,075 --> 00:11:20,846 They have dams, levees, canals, aqueducts. 188 00:11:20,879 --> 00:11:25,084 Some of the aqueducts are open like the South Bay Aqueduct 189 00:11:25,117 --> 00:11:28,687 shown here and some of them are pipelines 190 00:11:28,720 --> 00:11:31,924 and some of them are a combination of those 191 00:11:31,957 --> 00:11:36,829 with using different types of structures in different areas. 192 00:11:36,862 --> 00:11:39,765 Most of them serve a dual use. 193 00:11:39,798 --> 00:11:42,234 They both convey water around the state 194 00:11:42,267 --> 00:11:45,871 and they also serve as flood protection 195 00:11:45,904 --> 00:11:50,275 for the land around it and that's true of the dams 196 00:11:50,308 --> 00:11:53,679 and the levees and the canals and in some cases, 197 00:11:53,712 --> 00:11:57,216 the aqueducts, and if you look at this map 198 00:11:59,718 --> 00:12:03,923 which shows the water in red are the state aqueducts 199 00:12:06,591 --> 00:12:10,562 and yellow are the federal aqueducts and green 200 00:12:10,595 --> 00:12:14,032 are the local aqueducts where cities have bought 201 00:12:14,065 --> 00:12:16,502 water supplies on their own. 202 00:12:16,535 --> 00:12:19,471 In the Central Valley, there are three main aqueducts. 203 00:12:19,504 --> 00:12:22,174 There's the Delta-Mendota Canal, 204 00:12:23,575 --> 00:12:27,112 the East Side Bike Pass and there's the California Aqueduct. 205 00:12:27,145 --> 00:12:31,317 The California aqueduct is the granddaddy of all aqueducts. 206 00:12:32,751 --> 00:12:34,520 It is 700 miles long. 207 00:12:36,621 --> 00:12:39,324 It's 30 feet deep on average 208 00:12:39,357 --> 00:12:41,694 and 40 feet wide on average. 209 00:12:42,828 --> 00:12:45,998 It carries over 10,000 gallons per minute 210 00:12:48,967 --> 00:12:50,903 through this structure. 211 00:12:52,337 --> 00:12:55,808 So the California Aqueduct is a major structure 212 00:12:55,841 --> 00:12:59,311 and a lot of work goes into maintaining it 213 00:13:02,480 --> 00:13:05,951 but before I move on, I actually wanna draw your attention 214 00:13:05,984 --> 00:13:08,053 to these blue lines here. 215 00:13:09,454 --> 00:13:12,691 Those are the major rivers and if you just follow 216 00:13:12,724 --> 00:13:14,760 the pattern of the major rivers, 217 00:13:14,793 --> 00:13:17,563 you see that they kinda form a funnel 218 00:13:17,596 --> 00:13:21,500 that goes into this one area and that area 219 00:13:21,533 --> 00:13:24,537 is the Sacramento-San Joaquin Delta. 220 00:13:26,171 --> 00:13:29,808 So when water managers around the state 221 00:13:29,841 --> 00:13:32,444 are having their 3:00 a.m. thoughts, 222 00:13:32,477 --> 00:13:34,813 it's a pretty good idea that they're thinking 223 00:13:34,846 --> 00:13:38,083 about the Sacramento-San Joaquin Delta. 224 00:13:39,084 --> 00:13:41,687 So the Delta, it collects water 225 00:13:43,521 --> 00:13:47,860 from about 2/3 of the state and it distributes water 226 00:13:47,893 --> 00:13:50,996 to about 2/3 of the residents of the state 227 00:13:51,029 --> 00:13:54,499 for a lot of the agriculture in the Central Valley 228 00:13:54,532 --> 00:13:58,437 and for industry in Silicon Valley and so on. 229 00:13:58,470 --> 00:14:03,141 A lot of industry uses the water from the Sacramento Delta. 230 00:14:03,174 --> 00:14:07,345 It was formed around the late 1800s to early 1900s. 231 00:14:10,415 --> 00:14:13,085 This natural estuary was drained 232 00:14:15,420 --> 00:14:20,158 to form islands that could be used for agriculture 233 00:14:20,191 --> 00:14:24,229 because the soil was extremely rich, high peat content, 234 00:14:24,262 --> 00:14:28,066 high carbon content soil in that area. 235 00:14:28,099 --> 00:14:32,404 There are over 60 reclaimed islands in this one area. 236 00:14:32,437 --> 00:14:36,175 There's 1,100 miles of levee in this one area 237 00:14:37,309 --> 00:14:40,112 and most of the islands in the area 238 00:14:40,145 --> 00:14:43,382 now lie below mean sea level, in fact, 239 00:14:43,415 --> 00:14:47,452 on this map over here, only this dark green color 240 00:14:47,485 --> 00:14:51,089 is above mean sea level and that means 241 00:14:51,122 --> 00:14:53,659 that all of these areas of islands, 242 00:14:53,692 --> 00:14:57,863 almost every island is below mean sea level in that area. 243 00:14:59,331 --> 00:15:03,002 And this being the water hub for the state of California, 244 00:15:04,569 --> 00:15:07,539 maintaining those levees is a big deal 245 00:15:07,572 --> 00:15:11,443 because if a levee breaks, then saltwater comes back 246 00:15:11,476 --> 00:15:16,214 in to this area and it reduces the quality of the water 247 00:15:16,247 --> 00:15:20,919 below the point where it can be used for human consumption 248 00:15:20,952 --> 00:15:24,957 and it's also in many cases, not usable by agriculture 249 00:15:24,990 --> 00:15:27,726 because of the high salt content. 250 00:15:29,861 --> 00:15:33,265 Just to give you a personal perspective 251 00:15:33,298 --> 00:15:37,469 of what it looks like in the area, I took this photo 252 00:15:37,502 --> 00:15:40,973 from the top of a levee on Twitchell Island. 253 00:15:41,006 --> 00:15:43,542 This is the water and this is the land 254 00:15:43,575 --> 00:15:47,045 and the land is about 20 feet lower 255 00:15:47,078 --> 00:15:50,015 and that's really not unusual. 256 00:15:50,048 --> 00:15:53,385 Many areas have 30 feet, 20, 25, 30 feet 257 00:15:55,653 --> 00:15:58,324 so it didn't start out this way. 258 00:15:59,424 --> 00:16:02,060 Whenever these islands were formed, 259 00:16:02,093 --> 00:16:06,265 the land was in equilibrium with the natural processes 260 00:16:08,466 --> 00:16:12,070 of sediment accumulation and subsidence 261 00:16:12,103 --> 00:16:15,340 and so all of this subsidence has occurred 262 00:16:15,373 --> 00:16:18,043 since those islands were formed. 263 00:16:19,144 --> 00:16:22,714 In the Sacramento Delta, the primary cause 264 00:16:22,747 --> 00:16:26,051 of subsidence is aerobic oxidation 265 00:16:26,084 --> 00:16:29,321 of the soil, so it's not groundwater extraction 266 00:16:29,354 --> 00:16:31,523 like it is in some other areas, 267 00:16:31,556 --> 00:16:35,728 actually oxidation of these high carbon content soil. 268 00:16:37,562 --> 00:16:41,333 There are other processes at play like compaction 269 00:16:41,366 --> 00:16:44,836 from water withdrawal but the primary thing 270 00:16:44,869 --> 00:16:48,640 is that whenever you reduce the water content, 271 00:16:48,673 --> 00:16:51,944 the carbon began to oxidize off as CO2. 272 00:16:53,311 --> 00:16:56,681 So that's been going on since these islands are formed 273 00:16:56,714 --> 00:16:59,718 and the net result is that the higher, 274 00:16:59,751 --> 00:17:02,687 the richer the soil was at the beginning, 275 00:17:02,720 --> 00:17:05,657 probably the lower the land is now. 276 00:17:07,926 --> 00:17:11,997 So if that didn't keep people awake at 3:00 a.m., 277 00:17:13,531 --> 00:17:16,968 then thinking about the geological setting of the Delta 278 00:17:17,001 --> 00:17:19,738 certainly will, here's the Delta. 279 00:17:20,839 --> 00:17:23,509 It's all these jewel green islands 280 00:17:25,176 --> 00:17:29,948 and here's the Greenville Fault, here's the Concord Fault, 281 00:17:29,981 --> 00:17:32,851 the Calaveras Fault, the Hayward Fault, 282 00:17:32,884 --> 00:17:35,420 the San Andreas Fault. 283 00:17:35,453 --> 00:17:38,457 You've got a fault 10 miles, 15 miles, 284 00:17:38,490 --> 00:17:41,159 20 miles, 30 miles, 50 miles away 285 00:17:41,192 --> 00:17:44,229 and they just keep getting bigger and bigger. 286 00:17:44,262 --> 00:17:46,598 Any rupture, a major rupture 287 00:17:48,533 --> 00:17:52,637 on any of these faults could cause liquefaction 288 00:17:52,670 --> 00:17:55,841 that causes the levees to fail 289 00:17:55,874 --> 00:18:00,479 and the likelihood is that in a major earthquake, 290 00:18:00,512 --> 00:18:04,750 you'll have more than one levee fail in the Sacramento Delta 291 00:18:05,617 --> 00:18:08,087 and so saving the clean water, 292 00:18:11,055 --> 00:18:14,192 the clean water actually is coming in 293 00:18:14,225 --> 00:18:17,329 from the Sacramento River in the north 294 00:18:17,362 --> 00:18:20,899 and the water that comes in and the San Joaquin River 295 00:18:20,932 --> 00:18:24,536 from the South isn't nearly as high quality 296 00:18:24,569 --> 00:18:28,340 because it's runoff from these agricultural lands, 297 00:18:28,373 --> 00:18:31,409 has a lot of salts in it already. 298 00:18:31,442 --> 00:18:34,379 So these channels through the Delta 299 00:18:35,747 --> 00:18:39,151 don't only protect the islands from flooding 300 00:18:39,184 --> 00:18:42,154 but they also route the clean water 301 00:18:42,187 --> 00:18:45,257 from the Sacramento River through the Delta, 302 00:18:45,290 --> 00:18:47,125 through the east side of the Delta, 303 00:18:47,158 --> 00:18:50,962 down to pumps that puts the water into the aqueducts 304 00:18:50,995 --> 00:18:55,734 and sends it south and west to San Francisco area 305 00:18:55,767 --> 00:18:58,270 and Los Angeles and San Diego. 306 00:18:59,370 --> 00:19:02,707 So there's this delicate dance that's done 307 00:19:02,740 --> 00:19:06,912 with the control of these canals in order to prevent 308 00:19:08,546 --> 00:19:12,718 the low-quality water from the south from interfering with, 309 00:19:14,085 --> 00:19:16,588 from getting into these pumps. 310 00:19:18,022 --> 00:19:21,827 So it is a major source of concern for the state. 311 00:19:23,461 --> 00:19:27,299 And indeed, levee failures are not unheard of. 312 00:19:29,767 --> 00:19:33,572 On average, there's been about slightly less 313 00:19:33,605 --> 00:19:36,108 than one levee failure a year. 314 00:19:37,575 --> 00:19:41,680 It's kind of hard to see here but these yellow blips up here 315 00:19:42,847 --> 00:19:46,351 are the number of failures in winter years 316 00:19:47,518 --> 00:19:50,489 from 1900 to 2010, and there's a few, 317 00:19:53,958 --> 00:19:56,795 not many, but certainly notable failures 318 00:19:56,828 --> 00:19:59,164 that occurred in summer. 319 00:19:59,197 --> 00:20:04,035 So a lot of these winter failures or overtoppings 320 00:20:04,068 --> 00:20:07,606 are caused by high water but in the summer, 321 00:20:07,639 --> 00:20:11,810 that was not the case and the last serious levee break 322 00:20:13,177 --> 00:20:17,882 that occurred in the Sacramento Delta was on Jones Tract, 323 00:20:17,915 --> 00:20:20,986 no relation and it [audience chuckles] 324 00:20:21,019 --> 00:20:23,789 was in 2004 and this is the canal 325 00:20:26,624 --> 00:20:28,994 and this is the island; you see the island 326 00:20:29,027 --> 00:20:31,029 is just totally flooded. 327 00:20:32,630 --> 00:20:36,368 In fact, when this end of the island flooded, 328 00:20:36,401 --> 00:20:39,404 there was a berm that went across the center of the island 329 00:20:39,437 --> 00:20:41,239 which is then broke and flooded 330 00:20:41,272 --> 00:20:43,708 the other half of the island. 331 00:20:43,741 --> 00:20:47,679 It took about five months to fully repair this. 332 00:20:49,881 --> 00:20:53,084 The state's water supply from the Sacramento Delta 333 00:20:53,117 --> 00:20:54,686 was down for weeks. 334 00:20:56,287 --> 00:20:59,491 It took three weeks to repair the breach here 335 00:20:59,524 --> 00:21:04,229 and then it took about five months to pump all the water 336 00:21:04,262 --> 00:21:07,732 out of the island and it cost about $90 million 337 00:21:07,765 --> 00:21:10,935 and that's for one levee break. 338 00:21:10,968 --> 00:21:13,705 So the state worries about these levees 339 00:21:13,738 --> 00:21:16,241 and they try to maintain them. 340 00:21:17,975 --> 00:21:20,245 So this is where I came in. 341 00:21:22,714 --> 00:21:24,383 It was back in 2007. 342 00:21:25,783 --> 00:21:28,687 I was a new system engineer at JPL. 343 00:21:30,288 --> 00:21:34,259 I was working on this new instrument that was being built 344 00:21:34,292 --> 00:21:37,562 for the NASA Airborne Science Program. 345 00:21:37,595 --> 00:21:41,866 It was a radar, it had nice properties that I'll talk about 346 00:21:41,899 --> 00:21:46,071 and my colleagues and I would go and do test flights 347 00:21:48,106 --> 00:21:52,177 around California and the name of this instrument 348 00:21:53,611 --> 00:21:57,749 is UAVSAR and I'm sure you notice these portholes 349 00:21:57,782 --> 00:22:00,885 in these windows in the aircraft. 350 00:22:00,918 --> 00:22:04,522 This is not a UAV; it was actually designed 351 00:22:04,555 --> 00:22:08,660 so that the radar was in this pod underneath the aircraft 352 00:22:08,693 --> 00:22:12,664 so it could be popped off and maybe put on one 353 00:22:12,697 --> 00:22:14,999 of the larger UAVs but it actually flies 354 00:22:15,032 --> 00:22:16,702 on a Gulfstream III. 355 00:22:18,236 --> 00:22:22,407 And one day in March 2007, we were collecting data 356 00:22:23,841 --> 00:22:27,479 over San Francisco to look at some of the faults there 357 00:22:27,512 --> 00:22:31,683 and I noticed this, all these islands out the window 358 00:22:31,716 --> 00:22:35,420 and I came back and I looked into what that was 359 00:22:35,453 --> 00:22:40,358 and I realized that this instrument would be perfect 360 00:22:40,391 --> 00:22:43,828 for looking at the levees and so the next time 361 00:22:43,861 --> 00:22:47,198 we went out of that area, I collected a radar image 362 00:22:47,231 --> 00:22:50,569 and the reason that it's able to be used 363 00:22:52,170 --> 00:22:56,274 is that you can resolve the levees themselves. 364 00:22:56,307 --> 00:23:00,412 It has high enough spatial resolution to resolve the levees. 365 00:23:04,248 --> 00:23:07,919 If you can resolve the levees and monitor their condition 366 00:23:07,952 --> 00:23:11,956 from remote-sensing, then there's many advantages, 367 00:23:11,989 --> 00:23:16,027 obvious advantages over doing this from the ground. 368 00:23:16,060 --> 00:23:20,899 The first is that you can, this plane flies pretty fast. 369 00:23:20,932 --> 00:23:24,235 You can look at the entire Delta in a few hours. 370 00:23:24,268 --> 00:23:27,505 That means you can get a snapshot of the conditions 371 00:23:27,538 --> 00:23:32,310 at one time, driving around and looking at 1,100 miles 372 00:23:32,343 --> 00:23:36,648 of levees does not happen in a day or an hour or two hours. 373 00:23:36,681 --> 00:23:38,983 So this allows you to get a snapshot 374 00:23:39,016 --> 00:23:42,654 and go back and do frequent imagings. 375 00:23:42,687 --> 00:23:46,491 Also, it provides a consistent monitoring 376 00:23:46,524 --> 00:23:48,427 across all of the area. 377 00:23:50,595 --> 00:23:54,699 The levees in the Sacramento Delta are maintained 378 00:23:56,901 --> 00:24:00,705 by the owners with funding from the state 379 00:24:00,738 --> 00:24:04,042 but the owners, there's a lot of variance 380 00:24:04,075 --> 00:24:08,012 between the engineering firms and what kind 381 00:24:08,045 --> 00:24:10,982 of instrumentation they use to monitor the levees. 382 00:24:11,015 --> 00:24:15,086 There's not a consistent method for surveying 383 00:24:15,119 --> 00:24:18,590 or keeping track of what's going on in those levees. 384 00:24:18,623 --> 00:24:22,794 And also, it's just difficult to access some 385 00:24:22,827 --> 00:24:26,197 of these levees, some of these islands, 386 00:24:26,230 --> 00:24:29,701 you only get to through by a ferry that runs a few times 387 00:24:29,734 --> 00:24:32,404 a day and also most importantly, 388 00:24:35,506 --> 00:24:39,711 radar can do things that you can't do with the human eye. 389 00:24:41,145 --> 00:24:45,083 And a lot of that could be very useful in an emergency. 390 00:24:46,284 --> 00:24:48,987 So just what's so cool about UAVSAR? 391 00:24:52,890 --> 00:24:56,327 Well, it has to be able to do more 392 00:24:56,360 --> 00:24:58,663 than just image the levees. 393 00:24:58,696 --> 00:25:02,567 It's got to be able to measure something quantitative 394 00:25:02,600 --> 00:25:05,403 that relates to the health of the levee 395 00:25:05,436 --> 00:25:09,240 in order to be useful because we don't want to use it 396 00:25:09,273 --> 00:25:11,876 after the levee failed when an image will tell you 397 00:25:11,909 --> 00:25:14,746 where the levee failed, we probably already know that. 398 00:25:14,779 --> 00:25:18,216 We want to use it to tell where problem spots are 399 00:25:18,249 --> 00:25:22,153 before a levee fails, so let me just tell you 400 00:25:22,186 --> 00:25:25,023 a little bit about the instrument. 401 00:25:25,056 --> 00:25:29,227 It's actually a radar, side-looking radar and it hangs 402 00:25:30,561 --> 00:25:33,898 on this pod that's mounted below the fuselage 403 00:25:33,931 --> 00:25:38,102 of the Gulfstream III, the antenna is on one side 404 00:25:38,135 --> 00:25:40,638 and all the electronics that controls it 405 00:25:40,671 --> 00:25:42,974 on the other side in the pod. 406 00:25:43,007 --> 00:25:45,777 It operates at what's called L-band. 407 00:25:45,810 --> 00:25:50,148 That means it has about a 10-inch wavelength, 408 00:25:50,181 --> 00:25:53,518 microwave wavelength, and the advantage of that 409 00:25:53,551 --> 00:25:57,422 is that with that long a wavelength, you can see through 410 00:25:57,455 --> 00:26:00,692 most vegetation, so that you're not measuring the top 411 00:26:00,725 --> 00:26:02,694 of the vegetation; you're measuring what's happening 412 00:26:02,727 --> 00:26:06,130 on the ground below the vegetation. 413 00:26:06,163 --> 00:26:09,934 It's got really high spatial resolution, 414 00:26:09,967 --> 00:26:14,339 something like 5.5 feet by 3.5 feet pixel size 415 00:26:14,372 --> 00:26:17,308 for the instrument resolution and it operates 416 00:26:17,341 --> 00:26:21,446 from 41,000 feet above most traffic, air traffic, 417 00:26:22,647 --> 00:26:24,849 so it has a really wide swath width. 418 00:26:24,882 --> 00:26:29,053 It's got a 22-kilometer or 14-mile swath width 419 00:26:29,086 --> 00:26:33,258 so you're picking up your imaging a lot of area at one time. 420 00:26:34,825 --> 00:26:38,196 It moves, it really goes along at a clip about 421 00:26:38,229 --> 00:26:41,499 490 miles per hour and it's what I call 422 00:26:44,568 --> 00:26:49,107 a happy marriage between the aircraft and the instrument. 423 00:26:49,140 --> 00:26:52,443 The instrument tells the aircraft what to do 424 00:26:52,476 --> 00:26:55,913 and the aircraft does it; it's perfect. 425 00:26:55,946 --> 00:27:00,051 So the instrument tracks the aircraft position 426 00:27:00,084 --> 00:27:03,354 and controls the flaps of the aircraft 427 00:27:03,387 --> 00:27:08,259 so it flies a repeat tube and it flies the same position 428 00:27:08,292 --> 00:27:11,329 to an accuracy of about 16 feet, 429 00:27:11,362 --> 00:27:15,467 so about five-meter accuracy, and what you can do 430 00:27:16,834 --> 00:27:20,472 with that is something called radar interferometry 431 00:27:22,139 --> 00:27:24,976 where you can use the radar pulses 432 00:27:25,876 --> 00:27:28,546 to measure surface deformation 433 00:27:28,579 --> 00:27:32,850 and the way it works is kind of schematically shown here. 434 00:27:32,883 --> 00:27:36,587 So on the first pass, the aircraft goes over. 435 00:27:36,620 --> 00:27:38,289 It sends out pulses. 436 00:27:39,423 --> 00:27:42,126 They scatter from the surface down here 437 00:27:42,159 --> 00:27:46,564 and whenever they come back, you measure the amplitude 438 00:27:46,597 --> 00:27:50,034 of the signal that comes back and you measure where it is 439 00:27:50,067 --> 00:27:53,671 in that wavelength, and that relates 440 00:27:53,704 --> 00:27:57,508 to the distance to the ground but you only know 441 00:27:57,541 --> 00:28:00,912 the distance to the ground to that kind of wavelength scale, 442 00:28:00,945 --> 00:28:02,980 so you're only measuring, you're not really 443 00:28:03,013 --> 00:28:05,383 measuring the distance to the ground. 444 00:28:05,416 --> 00:28:07,919 You're tracking a phase along here 445 00:28:07,952 --> 00:28:11,456 so you'd get a first image and then you come along 446 00:28:11,489 --> 00:28:15,860 and you image a second time and the grounds moved 447 00:28:15,893 --> 00:28:19,030 and now, this is gonna scatter down here. 448 00:28:19,063 --> 00:28:23,334 It adds a distance and so the phase changes 449 00:28:23,367 --> 00:28:27,438 and the amount that the phase changes is related directly 450 00:28:27,471 --> 00:28:30,408 to the change in the distance to the ground 451 00:28:30,441 --> 00:28:34,879 along that line of sight, so now you can map 452 00:28:34,912 --> 00:28:39,684 the ground movement that occurred between these two passes. 453 00:28:39,717 --> 00:28:43,488 You can get a deformation map of the surface. 454 00:28:44,355 --> 00:28:46,357 So I just wanna show you 455 00:28:50,227 --> 00:28:54,298 a demonstration of what an interferogram, 456 00:28:54,331 --> 00:28:58,936 that's what we call that color fringe picture, tells you. 457 00:28:58,969 --> 00:29:03,541 So this is a picture of the San Andreas Fault. 458 00:29:03,574 --> 00:29:06,410 It's in Central California, north of Park Field. 459 00:29:06,443 --> 00:29:08,713 It's in the creeping section of the fault 460 00:29:08,746 --> 00:29:12,016 and the San Andreas Fault runs right along here. 461 00:29:12,049 --> 00:29:15,319 This is a radar image from UAVSAR. 462 00:29:15,352 --> 00:29:18,723 I think it's beautiful but I've been told by other people 463 00:29:18,756 --> 00:29:22,894 that this is not a terribly interesting image. 464 00:29:22,927 --> 00:29:26,697 You can see certain things; you can see individual trees, 465 00:29:26,730 --> 00:29:29,467 so we've got really good resolution 466 00:29:29,500 --> 00:29:33,671 but now let's compare this intensity image 467 00:29:33,704 --> 00:29:35,640 with the interferogram. 468 00:29:37,041 --> 00:29:41,079 Wow, now we know that there are three slow creep landslides 469 00:29:42,613 --> 00:29:45,583 within this one small area. 470 00:29:45,616 --> 00:29:49,788 This one image, interferogram, tells us the location 471 00:29:51,188 --> 00:29:54,992 and the outline and how much each of those areas has moved 472 00:29:55,025 --> 00:29:58,296 between the two imaging times. 473 00:29:58,329 --> 00:30:02,167 So that's what I wanted to apply to the levees 474 00:30:04,034 --> 00:30:07,205 in the Sacramento Delta, in this case, 475 00:30:08,606 --> 00:30:12,243 this is a very broad area, this is a really large landslide 476 00:30:13,777 --> 00:30:17,715 so I'm looking for much, much smaller features. 477 00:30:19,049 --> 00:30:22,954 So in 2008, I put in a proposal to NASA Applied Science, 478 00:30:24,588 --> 00:30:29,193 which was funded in order to do a pilot study, 479 00:30:29,226 --> 00:30:32,330 just a feasibility study, to see if we could really see 480 00:30:32,363 --> 00:30:36,534 motion on the levees, it's been going on since 2009. 481 00:30:39,270 --> 00:30:43,574 It was initially funded by NASA and more recently, 482 00:30:43,607 --> 00:30:45,676 it's been funded by California Department 483 00:30:45,709 --> 00:30:49,547 of Water Resources, with whom we work very closely 484 00:30:49,580 --> 00:30:53,851 in providing data on what's going on in the Delta. 485 00:30:53,884 --> 00:30:57,889 So we've had about 55 acquisitions and we image, 486 00:30:59,089 --> 00:31:02,493 we fly along and we collect swaths 487 00:31:02,526 --> 00:31:06,664 in kind of a racetrack pattern so we go back and forth 488 00:31:06,697 --> 00:31:10,034 and look at, that way we image every levee 489 00:31:10,067 --> 00:31:13,771 from multiple directions so that if that line of sight 490 00:31:13,804 --> 00:31:17,208 movement is along the slope, we can tell. 491 00:31:19,243 --> 00:31:23,047 There's a lot of things that can go wrong with levees 492 00:31:23,080 --> 00:31:26,150 that you would hope to be able to monitor 493 00:31:26,183 --> 00:31:29,820 with remote-sensing and I just wanted to talk to you 494 00:31:29,853 --> 00:31:33,257 a little bit about the kinds of things that happen 495 00:31:33,290 --> 00:31:35,493 and the kinds of things that happen 496 00:31:35,526 --> 00:31:38,462 specifically in the Sacramento Delta. 497 00:31:38,495 --> 00:31:42,667 Well, there's seeps and when the seeps carry material, 498 00:31:44,068 --> 00:31:47,571 they're called sand boils; this is a sand boil. 499 00:31:47,604 --> 00:31:51,776 There's cracks and slumps and erosion along the side. 500 00:31:54,812 --> 00:31:58,983 This is a slump where you just have a failure of the slope. 501 00:32:01,151 --> 00:32:05,022 This is a a slope where you have that slow creep 502 00:32:05,055 --> 00:32:09,660 that doesn't show up as a failure but it shows up 503 00:32:09,693 --> 00:32:13,264 as very slow deformation of poles or things 504 00:32:14,965 --> 00:32:17,535 that are put out in this area. 505 00:32:17,568 --> 00:32:20,604 You can get cracks where the levee just, you know, 506 00:32:20,637 --> 00:32:22,440 one of the slope just pulls away 507 00:32:22,473 --> 00:32:26,410 from the center line, and you can get subsidence. 508 00:32:26,443 --> 00:32:30,615 Broad area subsidence causes the levees to go down also 509 00:32:31,982 --> 00:32:35,720 and that raises the potential for overtopping. 510 00:32:35,753 --> 00:32:39,323 This is a a road and you can kinda see this dip over here 511 00:32:39,356 --> 00:32:43,728 where subsidence has caused the levee to be lower 512 00:32:43,761 --> 00:32:46,931 in that one spot and I point this out 513 00:32:46,964 --> 00:32:49,967 because it kinda shows the whole challenge 514 00:32:50,000 --> 00:32:53,671 of working in the Sacramento Delta. 515 00:32:53,704 --> 00:32:57,875 The soils there are so heterogeneous that they just, 516 00:32:59,910 --> 00:33:04,215 you will get subsidence that's dramatically different 517 00:33:04,248 --> 00:33:08,186 in one area from a really closely adjacent area 518 00:33:09,586 --> 00:33:13,691 and so the levee might be fine here or around the corner 519 00:33:13,724 --> 00:33:16,627 but it doesn't look so great there. 520 00:33:18,028 --> 00:33:21,298 And the Sacramento Delta, the speed limit on the levees 521 00:33:21,331 --> 00:33:23,701 is really should be taken seriously 522 00:33:23,734 --> 00:33:25,970 because potential problems. 523 00:33:28,539 --> 00:33:32,710 So the challenge with looking for problems on earth 524 00:33:35,746 --> 00:33:39,683 and levees this is demonstrated in this photo. 525 00:33:39,716 --> 00:33:44,622 This is a photo of the most rapidly subsiding levee 526 00:33:44,655 --> 00:33:47,291 in the Sacramento Delta, it's showing 527 00:33:47,324 --> 00:33:50,528 the most rapid movement and I'm just gonna let you 528 00:33:50,561 --> 00:33:53,431 look at it for a second and see if you can tell 529 00:33:53,464 --> 00:33:56,467 what's wrong with this levee. 530 00:33:56,500 --> 00:34:00,204 Because people would have to spot it driving. 531 00:34:02,639 --> 00:34:06,811 So there's a crack and that crack is about four inches wide. 532 00:34:09,079 --> 00:34:11,282 You practically have to step in the crack 533 00:34:11,315 --> 00:34:15,753 in order to find it, but it runs the length of this levee. 534 00:34:15,786 --> 00:34:19,290 So the levee here is pulling away 535 00:34:19,323 --> 00:34:22,660 and really, you have to be walking there 536 00:34:25,362 --> 00:34:28,065 or you have to use a remote-sensing technique 537 00:34:28,098 --> 00:34:32,270 in order to see this in any readily accessible way. 538 00:34:35,906 --> 00:34:39,443 So, I'm gonna show you the results that we got 539 00:34:39,476 --> 00:34:42,980 from remotely sensing the surface displacement 540 00:34:43,013 --> 00:34:45,783 on that levee, so that photo was taken 541 00:34:45,816 --> 00:34:48,819 from approximately here looking in this direction 542 00:34:48,852 --> 00:34:51,088 so the cracks ran along here. 543 00:34:51,121 --> 00:34:54,725 This is a surface deformation pattern in that area 544 00:34:54,758 --> 00:34:58,028 and the different colors correspond 545 00:34:58,061 --> 00:35:02,233 to different subsidence rates so downward movement rates 546 00:35:03,634 --> 00:35:07,905 on the levee and that shows that those cracks formed 547 00:35:07,938 --> 00:35:10,775 where there was a stress that was, 548 00:35:11,942 --> 00:35:14,812 differential subsidence was causing the levee 549 00:35:14,845 --> 00:35:17,115 to pull apart in that area. 550 00:35:18,182 --> 00:35:21,318 So we've done similar things looking 551 00:35:21,351 --> 00:35:25,523 for other potential problem spots and I show you this map 552 00:35:27,090 --> 00:35:29,760 that where we've just identified 553 00:35:29,793 --> 00:35:33,931 the most rapidly moving areas that are within about 500 feet 554 00:35:33,964 --> 00:35:37,735 of the crown of the levee and I show you this 555 00:35:39,136 --> 00:35:43,141 because it looks like there's a lot of really bad spots 556 00:35:44,508 --> 00:35:46,844 on this island; this is Jersey island. 557 00:35:46,877 --> 00:35:49,446 It's in the western part of the Delta 558 00:35:49,479 --> 00:35:54,118 and we're looking at the western end of Jersey Island 559 00:35:54,151 --> 00:35:58,322 but by working with the state, we learn which areas are, 560 00:36:01,325 --> 00:36:03,727 they assess from a map like this 561 00:36:03,760 --> 00:36:06,230 which areas are probably a problem 562 00:36:06,263 --> 00:36:09,667 and which areas are probably not. 563 00:36:09,700 --> 00:36:12,803 So for instance, this area is a levee 564 00:36:13,971 --> 00:36:17,107 that was relatively recently repaired 565 00:36:17,140 --> 00:36:20,678 and when they repair the levee, they add a lot of material 566 00:36:20,711 --> 00:36:25,249 and they pack it down and so they load the levee. 567 00:36:25,282 --> 00:36:30,187 It adds a load to the levee and it begins to subside, 568 00:36:30,220 --> 00:36:34,392 compressing the soils that are underneath the levee. 569 00:36:35,892 --> 00:36:38,596 And that's really not a problem because they account 570 00:36:38,629 --> 00:36:41,599 for the fact how much material they put on, 571 00:36:41,632 --> 00:36:44,635 accounts for the fact that it's gonna subside some. 572 00:36:44,668 --> 00:36:48,639 But this is an area where there was a levee break 573 00:36:48,672 --> 00:36:52,376 in the past and there, you might be having seepage 574 00:36:52,409 --> 00:36:56,581 or some other phenomenon and over here is another area 575 00:36:57,881 --> 00:37:02,219 where subsidence that appears to be centered 576 00:37:02,252 --> 00:37:06,357 in a field inland appears to also be encroaching 577 00:37:06,390 --> 00:37:10,461 on the levee, so I've been working with the state 578 00:37:14,665 --> 00:37:19,436 in the Sacramento Delta and during when the drought 579 00:37:19,469 --> 00:37:23,774 happened, the people, the engineering group 580 00:37:23,807 --> 00:37:26,610 that's responsible for operations and maintenance 581 00:37:26,643 --> 00:37:29,847 of the California aqueduct came to JPL 582 00:37:29,880 --> 00:37:34,051 and talked to several people and I showed them the results 583 00:37:35,185 --> 00:37:38,689 from the Sacramento Delta and they could see 584 00:37:38,722 --> 00:37:41,892 that with the kind of resolution that we were getting, 585 00:37:41,925 --> 00:37:45,062 that perhaps they could use it to tell 586 00:37:45,095 --> 00:37:48,565 whether there was an issue with the California Aqueduct. 587 00:37:48,598 --> 00:37:51,602 Now they thought, it was 2014, so they thought 588 00:37:51,635 --> 00:37:53,937 that there was potentially an issue, 589 00:37:53,970 --> 00:37:56,140 going to be an issue because they were in the middle 590 00:37:56,173 --> 00:37:59,943 of a drought and when there's a drought, 591 00:37:59,976 --> 00:38:02,613 there's increased groundwater pumping 592 00:38:02,646 --> 00:38:05,416 and when there's increased groundwater pumping, 593 00:38:05,449 --> 00:38:08,185 there's very frequently subsidence, 594 00:38:08,218 --> 00:38:11,989 particularly in the Central Valley of California. 595 00:38:12,022 --> 00:38:15,026 So the reason is because groundwater 596 00:38:18,061 --> 00:38:21,732 is kind of the fallback that the farmers use 597 00:38:24,401 --> 00:38:28,272 whenever surface water supplies are decreased 598 00:38:28,305 --> 00:38:32,943 so they make up a shortfall through using groundwater. 599 00:38:32,976 --> 00:38:36,280 And in a typical year, something like, average year, 600 00:38:36,313 --> 00:38:39,216 40% of the water demand would be met 601 00:38:39,249 --> 00:38:42,619 through groundwater withdrawal but in a dry year, 602 00:38:42,652 --> 00:38:46,657 it could go much higher than that, 60% or even more 603 00:38:46,690 --> 00:38:50,361 for some individual areas so we were looking 604 00:38:52,829 --> 00:38:57,001 at these two groundwater basins and what was going on 605 00:38:57,934 --> 00:39:00,137 in this stretch along here. 606 00:39:02,305 --> 00:39:06,310 So subsidence is not new to the Central Valley. 607 00:39:08,478 --> 00:39:12,149 It's been going on for as long as the people 608 00:39:13,083 --> 00:39:15,018 have been farming there. 609 00:39:15,051 --> 00:39:18,889 This poll shows the surface elevation in 1925, 610 00:39:20,390 --> 00:39:22,960 1955, 1977, so this was not new 611 00:39:27,364 --> 00:39:30,701 and this is a USGS scientist Joe Poland. 612 00:39:33,537 --> 00:39:37,708 More recently, another USGS scientist Michelle Sneed 613 00:39:39,810 --> 00:39:43,747 has kinda updated this poll with what's happening 614 00:39:43,780 --> 00:39:47,952 recently to show that the land has basically subsided 615 00:39:49,052 --> 00:39:52,223 her height since between 1988 and 2013. 616 00:39:58,195 --> 00:40:02,633 So what happens whenever you have groundwater withdrawal 617 00:40:02,666 --> 00:40:06,837 that causes subsidence is kind of outlined over here. 618 00:40:08,271 --> 00:40:12,576 Normally, you'll have, in an aquifer, you'll have sand 619 00:40:12,609 --> 00:40:16,413 and gravel and the water is stored in the pores 620 00:40:16,446 --> 00:40:20,618 between the little individual particles of sand and gravel 621 00:40:22,085 --> 00:40:25,189 and then there's also what are called aquitards 622 00:40:25,222 --> 00:40:29,393 which are layers of clay and silt and they're interspersed 623 00:40:30,861 --> 00:40:34,298 with the sand and gravel layers. 624 00:40:34,331 --> 00:40:38,502 And when you withdraw water, then the land surface 625 00:40:40,036 --> 00:40:43,740 does go down because you get some compaction 626 00:40:43,773 --> 00:40:47,478 from withdrawing the water but when it rains 627 00:40:47,511 --> 00:40:51,682 and you get recharge, then the part that's in 628 00:40:51,715 --> 00:40:54,518 the sand-and-gravel layer, it can be restored 629 00:40:54,551 --> 00:40:58,456 by adding the amount of water that you withdrew 630 00:40:59,823 --> 00:41:03,561 but whenever you withdraw water from these clays aquitards, 631 00:41:05,862 --> 00:41:08,999 then they collapse permanently. 632 00:41:09,032 --> 00:41:12,903 So think of those aquitards, those clay particles 633 00:41:12,936 --> 00:41:17,107 as being like flat plates and whenever you pull out 634 00:41:19,075 --> 00:41:22,847 the water, they will collapse and kind of sit 635 00:41:24,214 --> 00:41:27,484 on top of each other and there's no fluffing them up again. 636 00:41:27,517 --> 00:41:31,388 They're just permanently in this arrangement 637 00:41:31,421 --> 00:41:35,159 of their skeleton, so over time, what you see 638 00:41:37,994 --> 00:41:41,999 is a kind of soil variations in the water levels 639 00:41:44,200 --> 00:41:47,705 that correspond to recharge and withdrawal 640 00:41:48,905 --> 00:41:51,975 and then you see this long-term subsidence 641 00:41:52,008 --> 00:41:55,245 that either corresponds to withdrawing 642 00:41:55,278 --> 00:41:59,416 more than your recharging or to collapsing the aquitards. 643 00:42:02,719 --> 00:42:06,624 So this has been going on in the Central Valley 644 00:42:09,025 --> 00:42:12,829 and the amount of permanent subsidence depends a lot 645 00:42:12,862 --> 00:42:16,600 on upon how much of those aquitard layers they are. 646 00:42:16,633 --> 00:42:19,703 This is a map, this is Stockton here. 647 00:42:21,037 --> 00:42:25,042 Modesto, Merced, Fresno, Visalia and Bakersfield 648 00:42:26,109 --> 00:42:28,011 and then there's the Grapevine 649 00:42:28,044 --> 00:42:30,981 going over the mountains down here. 650 00:42:31,014 --> 00:42:35,185 California Aqueduct runs along here and in some areas, 651 00:42:36,586 --> 00:42:40,357 there have been up to a 30 feet of subsidence 652 00:42:41,691 --> 00:42:44,862 in the 56 years between 1949 and 2005, 653 00:42:49,165 --> 00:42:52,536 so just to put that in perspective, 654 00:42:52,569 --> 00:42:56,573 20 feet of subsidence, you have a two-story building. 655 00:42:56,606 --> 00:43:00,711 It's now below the ground, except the whole ground's 656 00:43:02,278 --> 00:43:06,550 gone down but it's now gone down that far. 657 00:43:06,583 --> 00:43:10,187 So that might not bother this cow over here 658 00:43:11,655 --> 00:43:15,793 but if you're have a well and a pipe connected to that well, 659 00:43:17,027 --> 00:43:21,098 then that subsidence is going to potentially 660 00:43:21,131 --> 00:43:24,702 cause some structural damage, shall we say. 661 00:43:25,969 --> 00:43:28,739 So critical infrastructure and structures 662 00:43:28,772 --> 00:43:31,875 in the Central Valley are often impacted 663 00:43:31,908 --> 00:43:34,144 by this kind of subsidence. 664 00:43:36,079 --> 00:43:39,817 So the aqueduct in particular can be affected 665 00:43:41,017 --> 00:43:43,988 by two things and I have examples here. 666 00:43:45,321 --> 00:43:49,826 One is subsidence from nearby groundwater pumping. 667 00:43:49,859 --> 00:43:54,364 So what happens is that the aqueduct is gravity fed 668 00:43:54,397 --> 00:43:56,567 and so if a part subsides, 669 00:43:59,269 --> 00:44:02,473 then the water comes closer to the top. 670 00:44:03,973 --> 00:44:08,345 It has less, what they call freeboard, and it can overtop 671 00:44:08,378 --> 00:44:12,082 more easily and so what they have to do 672 00:44:12,115 --> 00:44:16,386 is reduce the amount of water that flows through this area. 673 00:44:16,419 --> 00:44:19,890 They have to cut the water flow in the aqueduct 674 00:44:19,923 --> 00:44:23,193 in order to deal with the fact that there's a low spot, 675 00:44:23,226 --> 00:44:26,063 so that they don't get overtopping. 676 00:44:26,096 --> 00:44:29,766 I love this photo; this is a bridge going across 677 00:44:29,799 --> 00:44:33,971 the aqueduct and I promise you, they did not design 678 00:44:35,171 --> 00:44:37,474 the bridge so that the water of the aqueduct 679 00:44:37,507 --> 00:44:39,910 was lapping at the bottom of it 680 00:44:39,943 --> 00:44:43,313 but that's the situation today. 681 00:44:43,346 --> 00:44:45,416 This is just one example. 682 00:44:46,583 --> 00:44:49,052 There are many examples of this kind of thing 683 00:44:49,085 --> 00:44:52,389 that's happening in the Central Valley. 684 00:44:52,422 --> 00:44:54,524 But the other thing that can happen 685 00:44:54,557 --> 00:44:57,094 is that for some reason or another, you get a crack 686 00:44:57,127 --> 00:44:59,563 in the aqueduct lining and here's an example. 687 00:44:59,596 --> 00:45:01,598 This is a human pumping. 688 00:45:02,732 --> 00:45:05,535 They're pumping concrete in to fill 689 00:45:05,568 --> 00:45:07,671 this crack in the aqueduct. 690 00:45:07,704 --> 00:45:10,207 This is not a small structure. 691 00:45:11,674 --> 00:45:15,612 But you get water going through that crack 692 00:45:15,645 --> 00:45:18,181 to blow the aqueduct or to the side 693 00:45:18,214 --> 00:45:20,784 of the aqueduct and it causes compaction 694 00:45:20,817 --> 00:45:25,388 of the soil and that causes, ultimately, it can cause, 695 00:45:25,421 --> 00:45:30,026 show up as subsidence on the surface and it can also lead 696 00:45:30,059 --> 00:45:32,863 to further cracking of the aqueduct 697 00:45:32,896 --> 00:45:36,633 because it loses the soil support from below. 698 00:45:43,640 --> 00:45:47,811 In 2014, we started imaging the California Aqueduct 699 00:45:48,978 --> 00:45:52,649 and we were not given any new money to collect 700 00:45:54,584 --> 00:45:57,654 additional flight time so what we did 701 00:45:57,687 --> 00:45:59,623 was when we flew up to the Sacramento Delta, 702 00:45:59,656 --> 00:46:03,527 we would just aim the plane along the aqueduct 703 00:46:03,560 --> 00:46:07,130 and turn on the radar and collect the data. 704 00:46:07,163 --> 00:46:11,134 And this shows the cumulative displacement map 705 00:46:11,167 --> 00:46:15,005 between April of 2014 down here and June 2016. 706 00:46:18,441 --> 00:46:21,878 And we had collected some lines ahead of that, 707 00:46:21,911 --> 00:46:26,249 so we have a longer time series for this northern line. 708 00:46:26,282 --> 00:46:29,620 It goes back to July 2013 and this shows 709 00:46:34,824 --> 00:46:39,262 the pattern of subsidence that we see, which is very similar 710 00:46:39,295 --> 00:46:43,266 to what has historically been seen with the exception 711 00:46:43,299 --> 00:46:47,237 down here and this was something that showed up 712 00:46:48,638 --> 00:46:53,009 as a hotspot in the very first time I looked at the data. 713 00:46:53,042 --> 00:46:56,780 This is California Aqueduct runs through here 714 00:46:58,414 --> 00:47:01,685 and this is kind of a bull's-eye pattern 715 00:47:03,052 --> 00:47:06,824 is standard for pump groundwater withdrawal from a pump 716 00:47:09,425 --> 00:47:13,263 that would be located near the center of this feature. 717 00:47:13,296 --> 00:47:16,233 So I was pretty startled when I saw 718 00:47:16,266 --> 00:47:20,437 this kind of a deformation so quickly I went and showed it 719 00:47:21,838 --> 00:47:24,674 to the engineers and they drove out 720 00:47:24,707 --> 00:47:26,877 and they really couldn't see anything wrong 721 00:47:26,910 --> 00:47:29,479 so they sent out a leveling survey and sure enough, 722 00:47:29,512 --> 00:47:33,016 they, too, measured more than a foot of subsidence 723 00:47:33,049 --> 00:47:37,921 of the California Aqueduct over less than a two-year period 724 00:47:37,954 --> 00:47:42,459 and what I had seen was that I had watched it develop 725 00:47:42,492 --> 00:47:45,896 and I'd seen eight inches of subsidence in this area 726 00:47:45,929 --> 00:47:50,100 over a four-month period, so over the summer of 2014, 727 00:47:51,401 --> 00:47:53,637 there was eight inches of subsidence 728 00:47:53,670 --> 00:47:58,275 and they had no idea really how rapidly these things 729 00:47:58,308 --> 00:48:02,512 could form and how localized they could be. 730 00:48:02,545 --> 00:48:06,450 So this was a very useful information for them 731 00:48:07,617 --> 00:48:10,888 and they continued to support this work 732 00:48:12,689 --> 00:48:17,093 and use the results from it, so this is a photo 733 00:48:17,126 --> 00:48:19,029 of that subsiding area. 734 00:48:20,430 --> 00:48:23,500 I promised you they would not be very thrilling 735 00:48:23,533 --> 00:48:27,704 but you really don't see anything really hitting end, huh? 736 00:48:31,074 --> 00:48:33,510 So I'm gonna now show a movie that shows 737 00:48:33,543 --> 00:48:37,514 how the progression of the subsidence, how it occurred, 738 00:48:37,547 --> 00:48:41,952 and there's a date down here saying when the scene is from 739 00:48:41,985 --> 00:48:46,690 and I start at a time, not when there wasn't any subsidence, 740 00:48:46,723 --> 00:48:50,794 but before there was six inches of subsidence at the area, 741 00:48:50,827 --> 00:48:54,698 so this whole area, probably it subsided some 742 00:48:54,731 --> 00:48:57,300 but it was less than six inches so it doesn't show up 743 00:48:57,333 --> 00:49:00,103 on this map, so whenever you start to see colors, 744 00:49:00,136 --> 00:49:03,874 it'll be six inches up to 28 inches or more. 745 00:49:07,377 --> 00:49:08,211 Let's see. 746 00:49:11,014 --> 00:49:13,016 So here is the aqueduct. 747 00:49:15,451 --> 00:49:18,388 Here is I-5 and here at this center 748 00:49:21,290 --> 00:49:25,462 is an irrigation well that was installed in July 2013. 749 00:49:26,796 --> 00:49:29,699 It's a 2,500-gallon-per-minute pump and it's drilled 750 00:49:29,732 --> 00:49:32,302 to a depth of about 1,600 feet. 751 00:49:33,636 --> 00:49:37,807 And in January, it decreased in size slightly 752 00:49:37,840 --> 00:49:41,378 because it got some recharge and then after that, 753 00:49:41,411 --> 00:49:45,082 it began expanding in size so this was 2015. 754 00:49:46,649 --> 00:49:49,819 By now, you're up to 15 inches. 755 00:49:49,852 --> 00:49:54,024 Now you're around 18 to 20 inches by the beginning 756 00:49:55,358 --> 00:49:58,094 of the planting season of the next year 757 00:49:58,127 --> 00:50:02,299 and before it was done, there was something like 26 inches 758 00:50:03,699 --> 00:50:07,738 of subsidence directly of the aqueduct at that one area. 759 00:50:09,205 --> 00:50:13,676 And about five miles of the aqueduct had subsided 760 00:50:13,709 --> 00:50:16,546 by more than 10 inches, so this is 761 00:50:19,749 --> 00:50:22,018 very useful information for the state 762 00:50:22,051 --> 00:50:24,888 because they usually go out 763 00:50:24,921 --> 00:50:29,092 and they will repair the aqueduct in 40-mile sections 764 00:50:30,793 --> 00:50:34,664 but this tells them which sections to focus on. 765 00:50:34,697 --> 00:50:38,769 It allows it to be much more efficiently repaired 766 00:50:40,069 --> 00:50:42,639 and much more cheaply repaired. 767 00:50:44,107 --> 00:50:48,178 Oh, I do want to say that that one site decreased the pump, 768 00:50:48,211 --> 00:50:51,581 that one feature decreased the capacity 769 00:50:51,614 --> 00:50:55,786 of the California Aqueduct through this area by 20%. 770 00:50:58,254 --> 00:51:02,259 One, so there's also historically subsiding area. 771 00:51:04,160 --> 00:51:08,331 They have seen over 20 feet of subsidence in this area 772 00:51:09,866 --> 00:51:12,335 and we see that it's still subsiding 773 00:51:12,368 --> 00:51:16,172 in kind of a generalized pattern like they had seen before. 774 00:51:16,205 --> 00:51:19,275 We looked, went to look for more 775 00:51:19,308 --> 00:51:21,878 of these small-scale features 776 00:51:21,911 --> 00:51:25,749 that were not as drastic as the one at Avenal. 777 00:51:27,850 --> 00:51:31,788 This is a photo taken from this road back here 778 00:51:31,821 --> 00:51:35,024 looking across this field and here you have 779 00:51:35,057 --> 00:51:37,460 about nine inches of subsidence 780 00:51:37,493 --> 00:51:40,764 in this area and about six or so inches 781 00:51:42,365 --> 00:51:45,202 maximum along the aqueduct itself. 782 00:51:46,536 --> 00:51:49,639 This is an example of something that's just starting. 783 00:51:49,672 --> 00:51:53,009 Here is an example of hydro-compaction of the soil. 784 00:51:53,042 --> 00:51:55,645 In this case, we know that that's what's happening 785 00:51:55,678 --> 00:51:59,783 because the center of this feature is on the aqueduct itself 786 00:52:02,351 --> 00:52:04,854 and extends below it and that means 787 00:52:04,887 --> 00:52:08,691 that whatever's happening is happening below the aqueduct 788 00:52:08,724 --> 00:52:13,229 and so it has the classic signature of a crack 789 00:52:13,262 --> 00:52:15,598 in the aqueduct that's causing compaction 790 00:52:15,631 --> 00:52:19,969 of the soil below it and then this is an example 791 00:52:20,002 --> 00:52:23,840 where the state knew they had seep in the past 792 00:52:25,174 --> 00:52:28,811 and they had gone and repaired it all but we also see 793 00:52:28,844 --> 00:52:32,882 a small subsidence feature that seems to be centered 794 00:52:32,915 --> 00:52:36,886 less on the aqueduct itself, the side of the aqueduct 795 00:52:36,919 --> 00:52:41,091 is here, and more on the ground to the side of it. 796 00:52:42,425 --> 00:52:45,395 In that case, if you go to Google Earth, 797 00:52:45,428 --> 00:52:48,531 this has this arc pattern and you can find 798 00:52:48,564 --> 00:52:52,669 that the plants in that area are growing in an arc pattern 799 00:52:52,702 --> 00:52:56,540 because they have more moisture in the cracks. 800 00:53:01,677 --> 00:53:04,247 So the next thing that we're gonna try to do 801 00:53:04,280 --> 00:53:08,451 is to do seep detection; the current method is shown here. 802 00:53:09,619 --> 00:53:11,888 You're driving along and it's a hot day 803 00:53:11,921 --> 00:53:14,557 and it hadn't rained in a long time and you notice water 804 00:53:14,590 --> 00:53:18,127 running across the road at the bottom of the levee. 805 00:53:18,160 --> 00:53:21,197 Well, that's it. [audience chuckles] 806 00:53:21,230 --> 00:53:24,334 The other technique is to drive along 807 00:53:24,367 --> 00:53:28,104 and look for wetland vegetation in an area 808 00:53:28,137 --> 00:53:32,275 that should be dry, so we're trying to use, 809 00:53:32,308 --> 00:53:36,479 instead radar images and these slightly blue areas are areas 810 00:53:39,915 --> 00:53:43,386 where there's increased moisture in the soil. 811 00:53:43,419 --> 00:53:47,390 And in this case, this is a Mississippi River levee 812 00:53:47,423 --> 00:53:51,194 and these are relief wells that have been put in. 813 00:53:51,227 --> 00:53:55,231 This was during the big flood of 2011 and you can see 814 00:53:55,264 --> 00:53:59,736 these fingers of moisture coming in from probably 815 00:53:59,769 --> 00:54:04,240 from the relief wells that have been installed. 816 00:54:04,273 --> 00:54:07,844 You can also use the interferometry technique 817 00:54:07,877 --> 00:54:10,747 that I talked about before where you're just looking 818 00:54:10,780 --> 00:54:13,283 for something that's just a huge change. 819 00:54:13,316 --> 00:54:16,419 It's not really looking for a surface movement 820 00:54:16,452 --> 00:54:18,621 but just for a place where the surface 821 00:54:18,654 --> 00:54:20,623 has change dramatically. 822 00:54:20,656 --> 00:54:24,494 This is an example where we flew at high tide and low tide 823 00:54:24,527 --> 00:54:28,698 one day and we noticed change right along the bottom 824 00:54:30,766 --> 00:54:33,770 of the levee and when we went out 825 00:54:33,803 --> 00:54:36,372 to look at it in the field, we actually saw, 826 00:54:36,405 --> 00:54:39,609 this is the photo of that particular site. 827 00:54:39,642 --> 00:54:43,112 But this technique, where you're just looking for a change 828 00:54:43,145 --> 00:54:45,214 in the surface doesn't doesn't tell you 829 00:54:45,247 --> 00:54:47,350 what the cause of the change is. 830 00:54:47,383 --> 00:54:51,754 You really have to go out and see what happened there. 831 00:54:51,787 --> 00:54:54,324 And we saw several signatures like this 832 00:54:54,357 --> 00:54:57,527 and I just want to point out that in one case, 833 00:54:57,560 --> 00:55:00,363 [audience chuckles] we were looking at sheep, 834 00:55:00,396 --> 00:55:04,100 so having that partnership with the state 835 00:55:04,133 --> 00:55:07,203 where they have knowledge of what's going on 836 00:55:07,236 --> 00:55:09,205 and we can work with them has been 837 00:55:09,238 --> 00:55:13,142 really, really valuable in this particular project. 838 00:55:13,175 --> 00:55:15,679 So today, we use this aircraft 839 00:55:17,580 --> 00:55:21,751 and it's kind of the prototype for the NISAR mission, 840 00:55:22,852 --> 00:55:25,421 which NASA is now developing. 841 00:55:25,454 --> 00:55:29,125 It's supposed to launch in 2021 and it will provide 842 00:55:29,158 --> 00:55:32,962 comprehensive coverage of most of the land surface 843 00:55:32,995 --> 00:55:36,799 of the planet and certainly, all of the United States. 844 00:55:36,832 --> 00:55:39,535 Could be used for all kinds of hazards. 845 00:55:39,568 --> 00:55:42,405 You can still do things with the aircraft 846 00:55:42,438 --> 00:55:44,107 that you can't do with a satellite. 847 00:55:44,140 --> 00:55:46,676 In an emergency, you have to wait for the satellite 848 00:55:46,709 --> 00:55:49,145 to come over an area in order to image it, 849 00:55:49,178 --> 00:55:53,750 whereas, you can send the aircraft out to image right away. 850 00:55:53,783 --> 00:55:58,421 So they're complementary but one thing that you can't do 851 00:55:58,454 --> 00:56:02,291 with the aircraft is image every 12 days consistently 852 00:56:02,324 --> 00:56:04,794 the entire country and that's something 853 00:56:04,827 --> 00:56:07,864 that will be possible with this satellite. 854 00:56:07,897 --> 00:56:10,400 So takes a village, of course, 855 00:56:12,168 --> 00:56:14,904 so I had a lot of funding from NASA, 856 00:56:14,937 --> 00:56:17,640 from California Department of Water Resources 857 00:56:17,673 --> 00:56:21,611 and from the Department of Homeland Security 858 00:56:21,644 --> 00:56:23,980 in getting this project going and I have 859 00:56:24,013 --> 00:56:26,916 many, many colleagues who contributed 860 00:56:26,949 --> 00:56:29,719 to the work that I've shown and finally, 861 00:56:29,752 --> 00:56:32,789 I wanna really thank the UAVSAR teams 862 00:56:32,822 --> 00:56:34,991 at both JPL and Armstrong. 863 00:56:36,692 --> 00:56:40,864 JPL operates the radar and Armstrong operates the aircraft. 864 00:56:42,064 --> 00:56:45,835 So I will take questions while you look 865 00:56:45,868 --> 00:56:50,106 at this rapidly subsiding area in the Central Valley. 866 00:56:50,139 --> 00:56:52,408 [audience chuckles] 867 00:56:52,441 --> 00:56:56,446 Thank you. [audience applauding] 868 00:56:59,515 --> 00:57:02,752 So I'll take questions but I'm gonna ask that you use 869 00:57:02,785 --> 00:57:06,122 the microphone over there so that it's recorded 870 00:57:06,155 --> 00:57:09,659 for posterity [chuckles]. 871 00:57:23,506 --> 00:57:27,410 >> Hello, very interesting, in regard to JPSS-1, 872 00:57:30,379 --> 00:57:34,350 can you tell me whether or not it's equipped with radar? 873 00:57:34,383 --> 00:57:36,552 >> Catherine: I'm sorry, can you repeat the question? 874 00:57:36,585 --> 00:57:38,822 >> Yes, in regard to JPSS-1, 875 00:57:41,557 --> 00:57:45,728 can you tell me whether or not it's equipped with radar? 876 00:57:47,162 --> 00:57:50,900 >> I don't know what JPSS-1 is, I'm sorry [chuckles]. 877 00:57:50,933 --> 00:57:54,537 >> Okay it's Joint Polar Satellite Systems-- 878 00:57:58,040 --> 00:57:59,509 >> Oh. >> One. 879 00:57:59,542 --> 00:58:01,911 >> Okay, >> And it's gonna go 880 00:58:01,944 --> 00:58:05,348 from Vandenberg in November, next month, 881 00:58:06,515 --> 00:58:09,886 and one of a series of four that will go up 882 00:58:11,086 --> 00:58:14,491 and hopefully, utilize radar if they have it. 883 00:58:17,159 --> 00:58:19,395 >> I'm sure is not the same frequency 884 00:58:19,428 --> 00:58:21,864 as this particular radar. 885 00:58:21,897 --> 00:58:25,568 It would have probably a shorter wavelength 886 00:58:25,601 --> 00:58:29,038 so it would be one of the things that's better 887 00:58:29,071 --> 00:58:32,542 for looking at ice, and less good 888 00:58:32,575 --> 00:58:35,878 for looking through vegetation at the soil 889 00:58:35,911 --> 00:58:39,248 but we should talk afterwards and I can get you 890 00:58:39,281 --> 00:58:41,718 more information. >> Thank you. 891 00:58:43,052 --> 00:58:46,723 >> So I have some questions from people online. 892 00:58:50,159 --> 00:58:54,330 Lazy TV asks [chuckles] I'm assuming that's not his name, 893 00:58:56,365 --> 00:59:00,470 are the UAVSAR image scans used with ground surveys? 894 00:59:01,637 --> 00:59:04,974 What we do is how often we don't do it 895 00:59:05,007 --> 00:59:08,344 in conjunction with them because it's such a large area 896 00:59:08,377 --> 00:59:12,448 that rapidly subsiding site where I showed you 897 00:59:12,481 --> 00:59:15,718 the cracked levee and that does have 898 00:59:15,751 --> 00:59:20,456 some ground survey data there and whenever we give the state 899 00:59:20,489 --> 00:59:23,593 a particularly bad spot like that Avenal hotspot, 900 00:59:23,626 --> 00:59:27,797 they will go out and do a survey to verify what they see. 901 00:59:30,532 --> 00:59:33,836 Lucas asked, what is the probability 902 00:59:33,869 --> 00:59:36,739 of subsidence due to an earthquake? 903 00:59:36,772 --> 00:59:39,709 That's a very good question, Lucas. 904 00:59:39,742 --> 00:59:43,680 So I don't know what the probability is per se. 905 00:59:46,015 --> 00:59:49,285 That has been calculated and there's 906 00:59:49,318 --> 00:59:52,322 some uncertainty in the calculation. 907 00:59:55,024 --> 00:59:58,527 The subsidence that happens whenever there's an earthquake 908 00:59:58,560 --> 01:00:02,732 is called liquefaction so it's like you've jostled the soil 909 01:00:04,833 --> 01:00:09,271 and it settled out and the water has come out on top of it 910 01:00:09,304 --> 01:00:13,676 and you get rapid, very rapid subsidence when that happens 911 01:00:13,709 --> 01:00:16,279 and there's an issue about how, 912 01:00:18,180 --> 01:00:21,717 whether that would happen in the Sacramento Delta. 913 01:00:21,750 --> 01:00:25,922 They've done calculations for the levees themselves 914 01:00:27,723 --> 01:00:30,726 to show that the levees themselves 915 01:00:30,759 --> 01:00:34,597 are almost certainly gonna survive independent 916 01:00:37,833 --> 01:00:42,638 of what happens interior, however, you could get subsidence 917 01:00:42,671 --> 01:00:47,343 inside the island that causes a loss of support 918 01:00:47,376 --> 01:00:49,879 on the landside for the levee. 919 01:00:51,046 --> 01:00:55,051 Anyway, I don't know what the probability is 920 01:00:55,084 --> 01:00:57,754 but definitely is one, yes, sir? 921 01:00:59,555 --> 01:01:03,026 >> So you showed examples of the subsidence 922 01:01:05,060 --> 01:01:09,165 right next to the aqueduct caused by the pumping. 923 01:01:10,566 --> 01:01:14,404 Is there any plans to tell those people please stop pumping? 924 01:01:17,506 --> 01:01:20,943 >> Yeah, so I'm not sure whether the state 925 01:01:23,979 --> 01:01:26,916 approached them but in California, 926 01:01:26,949 --> 01:01:31,487 there isn't a law that prevents people from doing that. 927 01:01:31,520 --> 01:01:35,191 There's a law that prevents people from wasting water 928 01:01:35,224 --> 01:01:39,295 but there's not a law that prevents them from using water 929 01:01:39,328 --> 01:01:41,931 and since that pump was permitted, 930 01:01:41,964 --> 01:01:44,900 they have the right to use that water. 931 01:01:44,933 --> 01:01:48,437 So what the state is gonna do in the future, I think, 932 01:01:48,470 --> 01:01:51,640 I'm pretty sure that they've already done this 933 01:01:51,673 --> 01:01:54,610 is go to local communities and say, 934 01:01:54,643 --> 01:01:58,914 don't permit wells this close to these structures 935 01:01:58,947 --> 01:02:00,382 in the future. >> Yeah. 936 01:02:00,415 --> 01:02:03,686 I would think they would need to be a boundary layer, 937 01:02:03,719 --> 01:02:07,523 a boundary region around the aqueduct where no permits 938 01:02:07,556 --> 01:02:11,427 are permitted when the aqueduct was built. 939 01:02:11,460 --> 01:02:13,863 It's a little late to do it now. 940 01:02:13,896 --> 01:02:16,799 >> I don't think that they realized what the problem was. 941 01:02:16,832 --> 01:02:19,602 This was built in 1960s and '70s. 942 01:02:21,003 --> 01:02:23,339 It's kind of a shame but they are building 943 01:02:23,372 --> 01:02:27,676 the high-speed rail and other transportation structures 944 01:02:27,709 --> 01:02:29,879 that this can be used for. 945 01:02:32,815 --> 01:02:35,584 >> Thank you for the lecture. 946 01:02:35,617 --> 01:02:38,320 I actually enjoyed even more than I anticipated [chuckles]. 947 01:02:38,353 --> 01:02:40,289 [Catherine laughs] 948 01:02:40,322 --> 01:02:43,692 With all of the pumping that causes this subsidence, 949 01:02:43,725 --> 01:02:46,095 do we have a much of an understanding 950 01:02:46,128 --> 01:02:49,298 of what it takes to recharge the aquifer 951 01:02:49,331 --> 01:02:53,135 from rainfall and how long that might take? 952 01:02:53,168 --> 01:02:57,340 I think that people now are looking at how quickly 953 01:02:58,540 --> 01:03:01,177 the ground is coming back in this area 954 01:03:01,210 --> 01:03:04,380 with the rains from this past season. 955 01:03:04,413 --> 01:03:08,851 There are models of how fast it could be restored. 956 01:03:08,884 --> 01:03:12,321 I don't think all of the elevation change 957 01:03:14,056 --> 01:03:18,727 is reasonable to restore but part of it could be restored 958 01:03:18,760 --> 01:03:22,431 from that, so there are models and data like 959 01:03:23,632 --> 01:03:25,701 this helps to improve the models. 960 01:03:25,734 --> 01:03:27,837 >> Man In Cap: Okay, thank you. 961 01:03:27,870 --> 01:03:32,041 >> So Oscar asks, how can we contribute as educators? 962 01:03:33,208 --> 01:03:36,979 We have eager students for citizen science. 963 01:03:37,012 --> 01:03:39,682 That's a really interesting question. 964 01:03:39,715 --> 01:03:43,886 I think that citizen science, if I understand correctly, 965 01:03:43,919 --> 01:03:47,256 is people, just regular people going out 966 01:03:48,590 --> 01:03:52,127 and providing data to scientists so they take photos 967 01:03:52,160 --> 01:03:55,665 of ares or they report when there's a leak 968 01:03:57,099 --> 01:04:00,903 or something like that, so I actually could see 969 01:04:00,936 --> 01:04:05,007 a lot of value in something like that in areas 970 01:04:05,040 --> 01:04:08,277 where there's public access, of course. 971 01:04:09,378 --> 01:04:11,213 So that's a great question. 972 01:04:11,246 --> 01:04:14,383 Oscar, you should contact us. [chuckling] 973 01:04:14,416 --> 01:04:15,251 Okay. 974 01:04:16,551 --> 01:04:19,121 >> I know that there's certain members 975 01:04:19,154 --> 01:04:21,757 of certain congressional committees 976 01:04:21,790 --> 01:04:25,828 who have oversight over NASA who have said that NASA 977 01:04:25,861 --> 01:04:28,664 can look at all the planets except Earth. 978 01:04:28,697 --> 01:04:31,200 Have you run into that at all? 979 01:04:36,271 --> 01:04:39,642 >> What I know is that the earth science budget 980 01:04:39,675 --> 01:04:43,846 this year is really robust, so we're quite lucky, yeah. 981 01:04:47,316 --> 01:04:50,319 And I do, you're probably well aware, that NASA 982 01:04:50,352 --> 01:04:53,289 does a lot of earth science. >> Oh, yes. 983 01:04:53,322 --> 01:04:54,156 >> Yes. 984 01:04:56,591 --> 01:04:59,095 Thank you, any more questions?