The proposed temporary underdrain system may be used as part of the permanent system. The end of the drainage pipes could be installed with a valve (one-way valve) along with a standpipe for measuring the water level in the sand as shown in Figure 45. Sump pits with automatic pumps may be incorporated in the permanent drainage system. If there is a rise of the water level in the secondary canal during the initial stage of the storm, the valves of the drainage pipes should be closed (or one-way valve will prevent the reverse flow of water into the subgrade sand), and the pumps should take control of the water level of the sand layer instead of the drainage pipes. The proposed water level control scheme may be the only feasible option for maintaining the water level to acceptable values.