The article deals with the application of rock material dams with watertight element in the form of a screen or core in hydraulic engineering construction. The authors developed a new technology of watertight element creation. The technology consists in quick-setting substance introduction into every deposited dam layer with the help of a special chute. Experimental model research on the form and size determination of the quick-hardening substance lamination area inside the dam was carried out. Further the article considered the comparative calculations of the quick-hardening substance volume required for forming screen or core impervious elements. The possibility of dam construction cost decrease according to the developed technology and the core IE implementation was shown.