Geophysical logs were recorded in 32 wells in the confined-aquifer monitoring well network maintained by the Rio Grande Water Conservation District. Logging results were used to determine well construction, zones contributing water to the wells, and the purposes for which the ground-water levels measured in the wells can be used. The confined-aquifer well network consists of 42 flowing and nonflowing wells. This network consists of wells used to supply water for irrigation, household use, wildlife refuge supply, and stock use, and wells for water-level monitoring. Geophysical logs recorded in the wells included video, caliper, water specific conductance, water temperature, and water flow. Most wells in the confined-aquifer well network yield a composite water level representing water levels in multiple permeable zones in the confined-aquifer system of the San Luis Valley. A potentiometric-surface map constructed using November 2000 water levels indicates that water levels from most wells in the network are correlated with water levels from nearby network wells. Potentiometric-surface maps that are constructed from water levels measured in most of the wells in the network can be used to understand long-term local and regional changes in water levels in the confined-aquifer system. Water levels measured in 8 of the 42 wells in the confined-aquifer network are not representative of water levels in the confined-aquifer system.
