With respect to ecological and energy indices HTSs have large reserves, the realization of which can multiply reduce the consumption and pollution of large masses of water participating in hydraulic transport and filling with a simultaneous, and also multiple, decrease of energy expenditures. In terms of 1 billion tons of materials being transported, an increase of S/L just from 1∶20 to 1∶5 would approximately reduce water consumption by 15 billion m3 and energy expenditures by 1 billion kWh.The established practice of designing and operating HTSs with multiple reductions of the pulp consistency is explained mainly by the reliability requirements of the HTSs, which are most simply provided by increased water and energy expenditures.For a general evaluation of HTSs with respect to energy expenditures and water consumption it is recommended to use the proposed concept of efficiency of the system, which should figure in the main indices of HTSs characterizing its design virtues and perfection of operating technology.In the case of optimization, HTSs should be considered not closed systems but subsystems of a general system of constructing a hydraulic-fill structure. In view of the ever more obvious need to increase environmental protection measures in all areas of technology, the criterion of optimization of HTSs should include, in addition to reduced expenditures, efficiency as an index of water and energy consumption.