Water chemistry survey of Boulder Basin, Lake Mead

The survey results indicate that the impoundment of water behind Hoover Dam has not adversely affected the dissolved oxygen (DO) content and that water quality and DO content were uniform regardless of depth. The study made in April-May 1964 will provide water quality data of Lake Mead prior to releases from Lake Powell as a basis for evaluating Lake Powell\u27s effect on water quality and limnology of Lake Mead. The performance of a DO analyzer was tested and found unsatisfactory at depths below 150 ft. Parameters tested by standard chemical analyses of water samples in the Denver Laboratory and by field tests from a boat laboratory at 16 sampling stations on the reservoir were: pH, electrical conductivity, temperature, dissolved oxygen, and dissolved carbon dioxide. Results were: (1) pH at all stations was relatively constant except at Station 1 where the increase was probably due to release of carbon dioxide by decomposition of organic matter. More plant growth was observed here than at any other station. (2) DO content averaged 9.8 ppm at the surface and 8.6 near the bottom. (3) Except at Station 1 no dissolved carbon dioxide was found in the surface water. (4) Regardless of station or water depth, electrical conductivity was uniform throughout the basin. (5) Water temperature to 100 ft varied from 54.8 to 61.5 deg F and below this depth was quite uniform at 52 to 53 deg F