Hydrogeologic cross section through Sunshine Valley, Taos County, New Mexico
— W. Kelly Summers and L. L. Hargis

This paper presents a reinterpretation of hydrogeologic conditions in the Sunshine Valley area, east of the Rio Grande in Taos County. Winograd (1959) collected and studied an extensive suite of well records in this area and concluded that perched or partly perched aquifers are present, particularly in the large part of the area underlain by finegrained deposits which he thought were lacustrine. Our interpretation is based on data from 145 wells (Fig. 1), including many of those studied by Winograd. We have also used the records of 16 additional wells just beyond the northern and southern boundaries of the area shown in Figure 1. Our analysis led us to doubt the lacustrine origin and hydraulic-confining function of the fine-grained sediment, and we concluded that perched conditions are much less extensive than Winograd thought. We therefore proceeded to investigate the form of the main or regional water table on the assumption that any perched aquifers are local phenomena. 

We first describe our assumptions and procedures. Then we present an analysis of the vertical form of the flow field along a cross section normal to the river (Fig. 2), and discuss the difference between our interpretation and that of Winograd (Fig. 3).