[en] This document comprises four letter reports containing information that has been used in preparing the plan to characterize the site of the prospective repository at Yucca Mountain. The Yucca Mountain Project is studying the feasibility of constructing a high-level nuclear waste repository in the Topopah Spring Unit of the Paintbrush Tuff. One activity of site characterization is the construction of two exploratory shafts. The information in this report pertains to (1) engineering calculations of the potential distribution of residual water from constructing the exploratory shafts and drifts, (2) numerical calculations predicting the movement of the residual construction water from the shaft walls into the rock, (3) numerical calculations of the movement of the residual water and how the movement is affected by ventilation, and (4) measurement of the movement of water into a welded tuff core when a pulse of water pressure is applied to a laboratory test sample for a short time (100 min)