JOE ROSATO JR. >> Reporter: THE WORLD KNOWS NAPA AS A DESTINATION FOR VINEYARDS, FOOD, NATURE. IN THE MIDDLE OF THE CITY WHERE THE PEARL STREET BRIDGE CROSSES THE RIVER, ANOTHER KIND OF NATURE IS CARVING OUT A NAME FOR ITSELF. >> Reporter: IN BETWEEN THE CAT TAILS AND WILLOW BRANCHES YOU'LL FIND A DIY DAM. >> WE HAVE ALGAE, MUD, ROCKS. >> Reporter: BROCK, OF THE OBJECTION ACCIDENTAL ARTS AND ECOLOGY CENTER, IS AN ADMIRER OF THE ARCHITECTS. >> RECENTLY CHEWED DOWN. >> Reporter: THE COLONY OF BRIEFERS THAT MAKES ITS HOME ON THIS STRETCH OF RIVER. >> WE ARE IN THE CITY OF NAPA. THEY'RE IMPOUNDING THE CREEK AND INCREASING THE DEPTH OF THE WATER. >> Reporter: BEAVERS SWIM, FORAGE AND HIDE FROM PREDATORS. >> THEY STRIPPED IT OFF. >> BEAVERS HAVE SOMETIMES BEEN RECORDED AS A NUISANCE AND TRAPPED TO NEAR EXTINCTION. >> BY CREATING THIS NICE OASIS HERE, THEY'RE PROVIDING THESE BENEFITS TO A BUNCH OF OTHER SPECIES, THE FISH AND BIRDS. >> Reporter: DUCKS BASKING IN THE DAMMED UP WATER. THE ELUSIVE BUILDERS OF THESE COMPLEXES TAKE THEIR BOW. >> AMAZING, RIGHT? THE SUN HAS GONE DOWN. GOING UP ALL OVER LAND AND THEN HARVESTING WILLOWS AND THEN EATING THE FRESH WILLOW LEAVES LIKE A SALAD. >> Reporter: THEY HELP STORE WATER AND WETLANDS AND BUILDING IDEAL HABITATS. >> THE REST OF THE STATE IS CATCHING UP AND RECOGNIZING THAT. >> Reporter: KATE LUNDQUIST OF THE OBJECTION ACCIDENTAL ARTS AND ECOLOGY CENTER'S BRING BACK THE BEAVER CAMPAIGN SAYS GOVERNOR GAVIN NEWSOM DEDICATED FUNDING TO CREATE A RESTORATION PROGRAM. IT IS AIMED AT RELOCATING THOSE CREATING ISSUES WHERE THEY'RE NEEDED. >> THEY CAN HELP US BECOME MORE RESILIENT TO ALL OF THE IMPACTS OF CLIMATE CHANGE. >> Reporter: HERE IN THEIR PUBLIC NAPA HABITAT THE BEAVERS ARE GIVEN PLENTY OF APPRECIATION. >> IT IS URBAN WILDLIFE WATCHING. >> Reporter: IN THIS DESTINATION FOR WINE, FOOD AND NATURE, THESE CRITTERS ARE PUTTING SOME TEETH INTO THAT OLD EXPRESSION BUSY AS A BEAVER WITH PLENTY MORE WORK AHEAD. JOE
