Once upon a time, there was almost too much ground water in the Blackwater Draw area to deal with in deep excavations. Center-pivot irrigation came into vogue in the region from 1967.
Stories from the gravel mining era indicate that water was early on considered a hindrance here. Over time, the mine operators learned to utilize the water and isolate or flood pits as necessary, floating part of the operation on a barge built for that purpose. The water was consistent enough that the mine company kept the lakes stocked with fish, providing the employees and local people the rare chance to fish in Roosevelt county.
The archaeological crews, mostly students from Eastern New Mexico University, took advantage of the water for screening sediments and to cool-off in during the hot summer days on the Llano. By 1974, the near-surface water was gone, never to recharge. The long-term effects on deeply buried fauna is unclear. Although the area has seen continuous drying-out over the past 8,500 years, shallow, subsurface water was readily available until the mid-20th Century.
The Blackwater Draw National Landmark includes the disturbed gravel mine area in the center of the above photo, the center pivot field to the west, and the 1/2 Section to the south with the relatively undisturbed surface. Of course, the cultural and paleontological materials extend outwards in all directions from this arbitrary designation. Work has been done in all these areas over the past 80 years.