The document reports on the applicability of the DSDT hybrid computer techniques to the simulation of water resources systems and the solution of hydrology problems. The research objective was to investigate the feasibility of applying the DSDT method involving the use of an analog subroutine in a closed loop with a digital computer to the treatment of fluid flow. Previous and current studies using the DSDT technique were reviewed. The DSDT method was initially tested on the San Fernando Valley Basin. Six published papers dealing with the DSDT method were reproduced in the report. The authors demonstrated that various hydrology problems can be treated successfully using the analog subroutine approach. Small-scale simulations of aquifers will be continued in the future but attention will shift to the area of modeling and identification. Research is now underway to develop algorithms and program packages for processing raw field data since that is a major obstacle to the development of successful and dependable models of water resources systems.