captioning sponsored by wnet >> brangham: on this edition for sunday, august 14: violent protests in milwaukee after police shoot and kill a man police say was armed and fleeing. in our signature segment, one man's campaign to rid the oceans of plastics. at first a lot of people told me it was not possible, but the only way to find out is to actually try and go and do it. and, the most decorated athlete in olympic history, michael phelps, calls it a career. next on "pbs newshour weekend." >> pbs newshour weekend is made possible by: bernard and irene schwartz. judy and josh weston. the cheryl and philip milstein family. the john and helen glessner family trust. supporting trustworthy journalism that informs and inspires.

sue and edgar wachenheim, iii. barbara hope zuckerberg. corporate funding is provided by mutual of america-- designing customized individual and group retirement products. that's why we are your retirement company. additional support has been provided by:ompany. and by the corporation for public broadcasting, and by contributions to your pbs station from viewers like you. thank you. from the tisch wnet studios at lincoln center in new york, hari sreenivasan. this is pbs newshour weekend. >> brangham: good evening, and thanks for joining us. there is no relief in sight along the flood-ravaged gulf coast of louisiana and mississippi today. the national weather service has extended flood watches for parts of southeastern louisiana through this evening, following three days of relentless rainfall that sent many rivers flowing over their banks. forecasters say more than 20 inches have fallen over the last few days. what louisiana governor john bel edwards calls "historic" and" unprecedented" flooding has now claimed at least three lives.

the governor said today the number of rescues from homes and stranded cars has risen sharply to more than 7,000 people and 500 pets. >> even with the sunshine out today intermittently, the waters are going to continue rise in many areas and so this is no time to let the guard down, we actually have to remain vigilant. >> oh my god, i'm drowning! >> we're coming! >> brangham: in one dramatic rescue near baton rouge, a man pulled a woman from her car that was fully submerged in floodwaters, and then went back underwater to save the woman's dog. a louisiana emergency official says more than 5,000 flood evacuees are staying in shelters. calm is returning to milwaukee after a night of violent protests over the fatal police shooting yesterday afternoon of a man who police say was armed and fled a traffic stop. even so, wisconsin governor scott walker has activated the national guard to help milwaukee law enforcement, if needed, keep the peace.

the protests erupted after an officer fatally shot the suspect in a predominantly african- american neighborhood. milwaukee's police chief identified him as 23-year-old sylville smith and said he had a quote "lengthy arrest record." the police chief told reporters today smith did not obey orders to drop his weapon-- which was a stolen handgun loaded with 23 rounds of ammunition. the milwaukee journal-sentinel reports the officer was also black, citing police sources. after the shooting, protesters hurled rocks and bricks, smashed windows of two police cars, and set fire to a gas station and other businesses. one police officer was hit in the head with a brick, and police arrested at least three protesters. the milwaukee district attorney has opened an investigation into this shooting, and the officer involved has been placed on administrative leave. turning to the presidential race, today donald trump's running mate-- indiana governor mike pence-- dismissed a letter issued last week by 50 former national security officials, all from republican administrations, who argued that trump is too reckless to be trusted as commander-in-chief.

pence told fox news that the gop establishment levied similar criticisms of candidate ronald reagan back in 1980. pence also called for an investigation of contributions to the clinton foundation-- particularly the donations received while hillary clinton served as president obama's secretary of state. >> the public has a right to know. really and truly, this is exactly the kind of pay to play politics that the american people are sick and tired of. but frankly it is just one more example of the way i do believe the clintons have been operating for over 30 years. >> brangham: this request follows the release by the gro"" judicial watch" of 296 pages of emails it obtained in a "freedom of information act" request from the state department. the clinton campaign has said she never took action as

secretary of state because of donations to the foundation. learn why the aedes aegyptee mosquito transmits the zika virus better than nearly 200 other species in the u.s. visit www.pbs.org/newshour. at the olympic games in rio, the u.s. olympic committee confirms, american swimmer ryan lochte and three teammates were robbed at gunpoint early this morning by men posing as police officers who had stopped their taxi en route to the olympic village. none of the swimmers was injured. lochte has 12 olympic medals, second only in u.s. men's swimming to his teammate, michael phelps, who says he is retiring from competition-- for good, this time. this comes after phelps won his record 23rd gold medal last night-- his fifth gold in rio-- swimming the butterfly leg on the u.s. team's 4 x 100 meter medley relay. overall, from athens to beijing, london and rio, phelps has won 28 olympic medals, the most ever for any athlete in any sport. joining me now via skype from rio to discuss his incredible career is new york times reporter karen crouse.

karen, we are just running out of superlatives to describe this incredible career of michael phelps. can you help put his arb chievements into some context for us? >> reporter: he's not just a once-in-a-generation swimmer. he's a once-in-every-10 generation swimmer, or athlete, for that matter. it really is hard to wrap your head around 28 olympic medals when you know how hard it is to win a single one. michael last night called it insane, and i think that's as good a superlative as anything i can come up with. >> brangham: 31 years old, for most of us mortals, is pretty young, but not for an elite swimmer. how do you explain how he is able to keep this incredible record going? >> he has put in the work. he has a huge appetite for work, so i think it starts there.

he has wonderful talent. his long torso and short legs, but i think you saw in a couple of his races in rio what his will to win is. he gutted out that fly. i still don't know how he won it. he was seizing up in the final 10 meters, and i know that feel. he somehow found a way to get his hands to the wall first. it really speaks to the competitive nsync. >> brangham: phelps' return to the podium, certainly wasn't guaranteed, especially here in rio. for people who don't remember, can you remind us of some of the deviations his career-- maybe you call them ruts-- he went into that could have really stunted his progress. >> the year after beijing, he

was at a party with a few friends. everyone in that room he thought was a friend, and there was a marijuana bong in play, and that picture got out. so that was the first blemish. then he had a d.u.i., and a second d.usmed i.n2014, and that was rmally the turning point for michael. because after that second d.u.i., he went into recovery, a six-week program at the meadows in arizona. and it is astonishing the difference in him. it's almost as if he is a different person. he's the same swimmer but a completely different person, so much more self-aware, and so much more comfortable. >> brangham: as phelps leaves the world stage and leaves professional swimming,

apparently, what is his legacy on the sport itself? >> i believe what he's done in just bringing more people from more countries to sports. there were so many when there were six or seven countries represented in the top eight. i can remember a time when that was not the case. there would have been four countries at the most. so we owe that to michael, i believe. he had so many swimmers come up to him during the course of this competition and share with him, you know, i got my picture taken with you when i was six." "i got my picture taken with you when i was nine." katie ledecky had her picture taken with him when she was nine. the swimmer who finished fifth had her picture taken with michael at a meet in japan when he was eight.

these are people in the sport largely because michael inspired them to take it up. he made swimming look cool. and in my mind, that's his lasting legacy. >> brangham: already, karen crouse for the "new york times," thank you for your reporting and thank you for talking with us. >> thank you. >> brangham: as we make and use more and more plastic globally, the amount of plastic garbage ending up in our waters has increased dramatically. the united nations estimates plastic waste alone causes $13 billion in damage to marine ecosystems every year. this summer, a mostly-privately funded project launched its first major test to try and get some of that plastic out of our oceans and seas. in tonight's signature segment, newshour weekend's saskia demelker went to the netherlands to see how this model might work. >> reporter: 14 miles off the coast of the netherlands, boyan slat is conducting an experiment to rid the world's waters of

plastic trash. >> it's a perfect day to install a barrier. we've been working on this for quite a few years, and actually having something physical in the ocean that you can see work. >> reporter: this floating barrier in the north sea is the first test of this dutch 22- year-old's project that he calls "the ocean cleanup." >> ultimately, i hope that we can get to a future where the oceans are clean again. i would say that i think within 10 years from now, we would already be really close to getting clean oceans again, and perhaps in 20, 30 years, i think the oceans can be like they were in perhaps the 1950s, before we were using plastic at this scale. >> reporter: to call that goal ambitious would be an understatement. about 9 million tons of plastic are dumped into the world's oceans every year-- from littering on beaches, fishing vessels disposing of old nets, and improper waste management. that's enough plastic to fill a

football stadium and rise 23 miles in the air. scientists expect the amount of plastic trash in the oceans to double in the next decade as developing countries increasingly use plastic without adequate systems to recycle it. not only do fish and marine animals get entangled in plastic, they eat it. >> it's very likely that that was bites from a fish with a hard beak or it could be even a baby turtle. >> reporter: julia reisser is the ocean clean up's lead oceanographer. she says in water, plastic breaks down into microscopic pieces. so fish ingest plastic particles and may pass the harmful chemicals contained in them along the food chain. that's why it's critical to capture the large pieces of plastic before they break down. >> quantifying the microplastics, the very tiny pieces, you probably are looking at the levels of plastic pollution from a few decades ago. so it's like climate change: what we're doing now we might

feel in a few decades to come. so we see our operations as a way to intercept the big plastics before it becomes very small, tiny, millimeter-size plastics. >> reporter: rotating ocean currents suck plastic and other trash into concentrated areas-- one of the largest is the so- called "great pacific garbage patch" located between hawaii and california. scientists estimate that up to 170,000 tons of plastic accumulate here. ocean garbage patches are vast but dispersed making it difficult to collect or even see the plastic. last year, "the ocean cleanup" deployed 30 vessels to map more than 21,000,000 square miles of the pacific ocean and collect data on plastics. the team discovered more and larger pieces of plastic than expected. >> we got hundreds of times more plastic than marine life on the sea surface of these oceans. >> reporter: there's more plastic than fish? >> yes, at least at the sea

surface of this garbage patch, yes. >> reporter: boyan slat is focused on cleaning up this infamous patch. he was motivated six years ago, when he was on a family vacation. >> i was 16-years-old, and i was diving in greece, and then suddenly i realized i came across more plastic bags than fish. so i thought, well, somebody should do something about this. and then one day i realized that these currents between hawaii and california are rotating, so the plastic doesn't stay in one spot. i then asked myself, ¡hey, wait a minute, why would you go through the oceans if the oceans can also move through you?' >> reporter: in other words, slat wondered if the same ocean currents that pushed the plastic deep into the ocean could be harnessed to clean it up. slat came up with the idea to anchor a structure to the ocean floor similar to an oil rig-- a passive barrier that could trap plastics. >> the oceanic currents moving

around is not an obstacle, it's a solution. >> reporter: when slat, as a s idea in this "ted talk" four years ago, the video went viral. and with thousands of supporters, he decided to drop out of college to start the ocean clean up. what were the reactions to your idea at that time? >> at first a lot of people told me it was not possible. i thought, well, i don't know whether it's possible, but the only way to find out is to actually try and go and do it. >> reporter: through crowdsourcing, he raised $2.2 million dollars within 100 days and now has attracted a staff that includes dozens of scientists and engineers. two years ago, slat co-authored a 528-page report with nearly 100 scientists outlining how his vision could work and then began testing scale model barriers in wave pools. in june, he began testing out at sea. the flexible barrier, as shown in this animation will float atop the ocean's surface, its arms outstretched in a "v" shape.

a rubber screen will extend six- and-a-half feet below which the designers claim is deep enough to catch plastics, but shallow enough that marine life can swim underneath it. as plastic accumulates in the center of the barrier, it will be pulled up into a tower and stored until it can be transported back to shore and recycled. >> in the north sea the waves and currents are actually stronger than those out in the pacific ocean. that's why the ocean cleanup team is testing the structural integrity of the floating barrier here first. >> so we have the big yellow buoys those are the buoys that will hold the barrier. >> reporter: allard van hoeken is an offshore engineer and the project's chief operating officer. he's overseeing the year long barrier test. what do you expect from this test here? >> so now we're going to see how the barrier will behave in a real offshore environment, real sea conditions. and also we're going to do tests. so we're going to do a capturing test with the fake plastic, it's not real plastic, it's made out of corn. and we're going to release it here in front of the barrier and see how the barrier holds that. >> reporter: after this test, van hoeken's team of engineers will set their sights on the

pacific ocean, where they hope to deploy a full scale 62 mile barrier by 2020. >> to put a structure like this in the ocean far away from the coast, thousands of miles away in an area where humans have no control at all. to place it there, make it survive year after year. that's really a lot of things together that have never been done before. >> reporter: the ocean cleanup team has yet to secure funding for the full scale barrier, which it estimates will cost hundreds of millions of dollars. while most of boyan slat's funding has come from private donations the dutch government recently gave $550,000 for the prototype test. sharon dijksma is the dutch minister for the environment. >> we don't have a pocket full of money waiting for boyan after this, but i think the first step getting the prototype out and to be paid for that was probably the hardest step. when this is a success, and he is going to scale up, i think the investors will stand in line to assist him.

>> reporter: but nick mallos, director of the "trash free seas" program at the ocean conservancy in washington d.c. is among the skeptics. from what you know about the ocean cleanup plan, is it a feasible proposition? >> i think there are a lot of factors that are quite concerning. we're talking about putting the largest manmade object ever known into an ocean in an environment that is one of the most, if not the most, dynamic and, and dangerous ecosystem on the planet. i think at the moment we believe the risk of catastrophe outweighs the potential benefit of plastics extraction. >> reporter: boyan slat says that that risk can be mitigated. that's why they're testing extensively. mallos says a more cost effective low risk approach is to slow plastic consumption and capture plastics in coastal areas. >> we believe very strongly that we should focus on stopping debris and plastics from entering waterways and the ocean at its source through beach cleanups and waterway and near

shore clean ups and redesigning and minimizing the amount of waste that's available to ever enter the system. >> i think that prevention and cleanup is highly complementary. because already there is a massive amount of plastic in the ocean, and it doesn't go away by itself. it's a dirty job, but someone's got to do it, i suppose. >> brangham: russian prime minister dmitry medvedev said friday that russia could break diplomatic ties with ukraine over what it says were recent ukrainian attempts to sabotage infrastructure in crimea. russia annexed the small ukrainian peninsula two years ago, prompting an international outcry. on thursday, ukraine puts its army on combat alert, after reports came in that russia was amassing thousands more troops and equipment in crimea. joining me now by skype from moscow to discuss this tense situation is "washington post" reporter andrew roth.

so, andrew, i've been reading somewhat observers are saying that this russian military buildup could be preparations for a big, possibly substantial fight, possibly into u.n. security council. is that your sense of what's happening there? >> well, i think it's a little bit early to jump to any conclusions like that. there have been warnings from some observers about impending invasions, serious invasions from russia into ukraine, basically since the conflict began in 2014. but it is a fairly serious ebb alation at the moment in terms of the sort of souring of diplomaticitize between the two countries. and russia has moved some fairly substantial amount of tanks and also certain other weapons into crimea. they're holding military exercises there at the moment. >> brangham: russia says in recent days it's disrupted several attempts by what they argue are ukrainian special forces to go in and sabotage

something inside crimea. is there evidence those attacks were being planned? >> i think this is difficult to tell. it's sort of a he said-she said situation at the moment. the russians came out with this sort of bombshell accusations this week that the ukrainians had been, through their intelligence director, trying to carry out some high-level sabotage attacks, and . putin called them pertryst attacks. but in terms of concrete proof, we're not quite there yet. we've seen, though the russians have made public basically a confession by yevgeny pomov, who used to fight in ukraine as a member of the armed forces. but it's not very clear whether or not any of the allegations that they've made that he's a member, sort of intelligence agent, are true. but what is clear is that they made a decision based on that to

escalate this and for putin to call it a terrorist attack. it's sort of the most serious rhetoric they could use. >> brangham: if this isn't for a conventional incursion into ukraine, what else might russia be up to? >> i mean, there are suggestions that one thing the russians might be interested in is increasing instability, as a sort of means to gain leverage in international negotiations. it's possible the russians want to change the way negotiations about ukraine are run. currently it's in the context of the normandy four, which is france, germany, ukraine, and russia. president putin says that's not possible to do anymore, although, in ukraine, they say that it still is. another thing that could be happening is the russians have decided that that he want to put ukraine on notice, and that they decided that this is sort of the best way to do it. >> brangham: all right, andrew roth of the "washington post," thank you very much for joining

us. >> thank you. >> brangham: the islamic militant group boko haram has released a video that purports to show dozens of the nearly 300 nigerian girls it abducted from their school more than two years ago. in the video, posted today to twitter, one of the girls says that 40 of them have been married to militant men, and that some girls have been killed in nigerian air strikes aimed at the militant camps. while a militant held her microphone, she also appealed to the nigerian government to free jailed members of boko haram. the militant in the video said if the government does not free boko haram prisoners, the kidnapped girls will never be released. a spokesman for the "bring back our girls" campaign-- and one of the girl's mothers-- said the video appeared to be authentic. 218 girls remain missing. new york city police are searching for the killer who gunned down an imam and his assistant in broad daylight near

a queens mosque that serves the local bangladeshi muslim community. police say security camera video shows both victims were wearing traditional muslim religious clothing when a man approached them from behind, shot them in the head, and ran away. both men had just attended afternoon prayers. the imam was carrying more than a thousand dollars in cash, which was not taken. some members of the community are asking the n.y.p.d. to treat the murders as a hate crime, but police say nothing yet indicates the victims were targeted because of their faith. a milestone in flint, michigan, today, though most residents may hardly be aware of it. the federal "emergency declaration" for the city's lead-tainted drinking water has expired. the state will now pay the full cost for supplying residents' bottled water and filters for their taps. the federal government had been covering 75-percent of those costs, which ran to three-and- half million dollars a month. federal health and environmental monitoring programs will continue as before.

>> brangham: returning to rio, golf is back at the summer olympics for the first time since the st. loose games of 1904 and she today the winner of golf's first gold medal in 112 years was britain's justin rose. with a birdie on the last hole, he beat stenson, who shot a bogey and settled for silver. that's all for this edition of "pbs newshour weekend." i'm william brangham. good night. captioning sponsored by wnet captioned by media access group at wgbh access.wgbh.org

>> pbs newshour weekend is made possible by: bernard and irene schwartz. judy and josh weston. the cheryl and philip milstein family. the john and helen glessner family trust. supporting trustworthy journalism that informs and inspires. sue and edgar wachenheim, iii. barbara hope zuckerberg. corporate funding is provided by mutual of america-- designing customized individual and group retirement products. that's why we are your retirement company. and by the corporation for public broadcasting, and by contributions to your pbs station from viewers like you. thank you. [jazz plays]

man: it's called "the movie palace," and it's sort of like a little temple. it's almost like a religious shrine to the movies. these are like sort of depictions of different movie genres. this would be like the epics, "ben hur" type movie. this is sort of film noir. egg shell up here. this is actually chicken egg shells. these are wood, but they're made to look like they're copper. are you ready? people kissing and smooching.