[en] This report presents results and description of hydrologic test activities for the Rattlesnake Ridge interbed and Pomona basalt flow top at Borehole DB-15. Hydrologic tests conducted include constant discharge air-lift and constant discharge submersible pumping tests. An observed hydraulic head for the test interval was 409 ± 1 feet above mean sea level. Transmissivity values determined from hydrologic tests performed, ranged between 493 and 469 ft²/day. The best estimate of transmissivity is 480 ft²/day. The best estimate of equivalent hydraulic conductivity, based on an effective test thickness of 56 feet is 8.6 ft/day. 4 refs., 7 figs., 2 tabs