outwardly to the perimeter thereof it is necessary to utilize a vehicle which is operable on water and maneuverable in sludge and clay therefore a lightweight amphibious vehicle 21 which is floatable upon water is utilized in fig6 the vehicle is shown as including rotary driven hollow pontoons 33 and 34 which support the frame of the vehicle in an elevated position with respect to the water appropriate power means are provided on the vehicle for rotating the drums which drums are provided with fluted surfaces for purposes of creating propulsion through water and clay one such type of vehicle is disclosed in applicants 39 copending application ser no 07 906 446 filed jun 30 1992 entitled amphibious land reclamation vehicle with particular reference to fig6 the lightweight amphibious vehicle 21 carries a high pressure centrifugal pump 26 to which is mounted a discharge line 36 the pump extends downwardly relative to the vehicle and through thin crusted surface areas so that it is located within the clay layer 11 of the settling pond the pump is inserted well within the clay layer to avoid pumping of water in order to allow pumping of the clay a mechanical agitator such as a rotatable blade 37 may be mounted adjacent to the pump which blade is used to mix the pudding consistency clay to a.