It was a family affair, but the significance was national: President Bush and his brother Jeb, the governor of Florida, signed an agreement yesterday to guarantee that water captured by a $7.8 billion Florida Everglades restoration effort will indeed go toward reviving the national park. Because the state and federal governments have potentially competing interests in the project — the feds want to protect the park, the state wants water for business and agricultural interests as well — Congress mandated that both parties sign a water-use agreement. Although environmentalists have frequently expressed concern about the regulations guiding the restoration project, many green groups said they were pleased with the Bush-Bush agreement.