Televised ducts under slab floor. Ducts are concrete possibly Transite with metal connections and fittings that are rusting and deteriorated in the front of the house. There are drainage issues with downspouts and a retention wall that could be contributing to the deterioration in the front of the house. Suggest making changes to the landscape and downspouts then spin cast mortaring the metal fitting and spray lining the system with Duct Armor duct lining material.