TEMPLE TERRACE — Standing at the shoreline of Riverhills Park in Temple Terrace, where the Hillsborough River is wide and majestic, Bob Luce points out something unnatural in the vista, a plastic blob about the size of a five-gallon water bottle floating in the middle.“It just kind of ruins the whole image,’’ he says.That was the motivation more than a decade ago for his one-man campaign to protect the river. He wanted to take wildlife photos, but trash kept getting in the way, so he removed it. It became a never-ending effort.In his inflatable kayak, he patrols a 5-mile stretch of the river in Temple Terrace usually twice a week, going out for two or three hours at a time. Using litter grabbers of varied lengths, he fills up a tub and trash bags until there is no more room in the boat. He figures he has removed more than 40,000 gallons of trash from the river in 10 years.Not just river-going litter bugs put it there. Someone riding on the street a few blocks away could have tossed out a candy wrapper, which the next rainstorm swept into a storm drain, which dumped it in the river. If it misses the clutches of Luce’s litter-grabber, the river carries it through South Tampa to the bay and possibly beyond.“We live in a plastic, throw-away society,’’ said Luce, a bespectacled, fair-skinned man of 73, who wears a fisherman’s floppy hat and sun-protective shirt for river work. “Everyone has plastic water bottles and plastic bags and Styrofoam cups, and they don’t dispatch with them properly, so they just figure, ah, throw them here and there, willy-nilly, whatever. But stuff out in that street is going to end up right here.’’Along with the waterborne plastic and polystyrene, Luce retrieves big trash. One time, he took a sledgehammer out with him to break apart a couch someone had dumped in shallow water, taking it in pieces to shore for the city to pick up. He’s pulled up television sets, bicycles, tires, wheels and more than a few open safes, always empty. He calls the police when he finds a safe, figuring it was dumped after a burglary.In addition to removing eyesores, Luce records the river’s beauty. He frequently posts pictures on Facebook of great blue herons, great egrets, roseate spoonbills, night herons, limpkins and alligators, lots of gators.Usually, the gators take off when he comes near, he said. The females stand their ground, especially if babies are around. Sometimes one will glide toward him, mouth open and hissing. He wants to get in closer for a good picture, so he talks to them gently, as one would talk to a dog. He tells of one he’s watching about a half-mile upstream.“The first time I got close to her, she got real huffy, and I backed away,’’ he said. “Each time she takes a little longer to get upset, and now she doesn’t come all the way to the boat with her mouth open. Now she just looks at me and watches me.’’A retired computer programmer, Luce began his clean-up effort in Sweetwater Creek off Dale Mabry a few years after he and his wife, Christine, moved to Carrollwood in 2003. For a long time, he wore waders to go into the water and retrieve trash that gathered at the stream’s edge. He still used waders when he started concentrating on the Hillsborough River in 2008, then bought his kayak in 2011.It takes about 20 minutes for him to inflate his kayak and load it up. He carries an anchor in case he wants to wade to shore to retrieve a piece of litter. He brings along a gallon jug of ice water and lunch, perhaps a can of salmon. In addition to the square plastic tub, which he fills up first, he brings along a couple of 18-gallon bags and at least one 42-gallon bag. And he also takes along his Sony RX10 digital camera, which he keeps in a waterproof bag. When the trash containers are full, he comes back in.His efforts have not gone unnoticed. Environmental groups have honored him, and recently he was given the River Stewardship Award by the Hillsborough River Interlocal Planning Board and Technical Advisory Council.“I think Bob is a tremendous asset to the community,’’ said Temple Terrace City Council Member Andy Ross, who represents his city on the river planning board. “He has a passion for the river and what he does is hard to put a value on.’’Luce said what he would prefer over awards would be for government to spend more money managing the litter by installing and maintaining Watergoats, litter dams at storm water outlets in the river. He would like to see a strong public relations effort against littering. He wants to see the result of littering — waterways filled with trash — taught widely to school children.“They’ve got to show them the impact,’’ he said.Contact Philip Morgan at email@example.com or (813) 226-3435.