Technical Reports Document Library

2009 marked the eighth year of operations for the Edwards Aquifer Authority (EAA) by the Southwest Texas Rain Enhancement Association (SWTREA). The project duration was the same as it has been the past couple of years, with seeding taking place in Uvalde County from May until September. Drought conditions that originated in late 2008 continued into most of 2009, which in tum had an effect on seeding operations for most of the summer. …. Seeding in the Authority target area of Uvalde County saw a total of twenty-four seeding flights for the 2009 operational season. …

As was the case last year, in addition to normal weather modification activities in the Edwards Aquifer Authority (EAA) target area, 2009 was the third year for a randomized seeding experiment. The randomized seeding experiment was also conducted by the EAA’s other weather modification contractor, the South Texas Weather Modification Association (STWMA). … Due to bias that could occur the experin1ent was double blind so that ground operations staff would not know which clouds were seeded and which were not seeded. …

No randomized seeding flights took place in Uvalde County during the 2009 season. The reason for no flights during the season was due to the fact that most ofthe convection in the EAA target area did not meet the randomized criteria. …

At the September 30th conclusion of the 2008 operational season for the EAA target area, a radar evaluation was completed for the program. The findings are presented and discussed towards the end of this report. The flight logs for the 2009 seeding season are [shown].