Technical Reports Document Library

2006 marked the fifth year of operations for the Edwards Aquifer Authority (EAA) by the Southwest Texas Rain Enhancement Association (SWTREA). The project this year was business as usual, with seeding taking place in Uvalde County from May until October. There was caveat this year. Due to the continuing drought of most of South Texas, seeding missions were hard to come by throughout most of the year. A few months of the year did see increased activity, but the majority of it was hot and dry.

Drought conditions did tend to improve towards the latter part of the year with the development of a moderate El Nino episode in the South Pacific off the coast of South America. When El Nino’s tend to develop, the southern half of the United States tend to benefit greatly from the increase intensity of the subtropical jet.

Seeding in the Authority target area of Uvalde County saw a total of twenty flights for the 2006 operational year compared to twenty flights in 2005. Also, with the continued cooperation between the two seeding projects, SWTREA flew a total of two missions in Medina County and one in Bandera County for the South Texas Weather Modification Association (STWMA). As seen above, there were more missions in 2005 than 2006, due to the lack of convection across the Aquifer area. Most of the systems seeded in the EAA target were classified as small clouds, or systems that were not large in area. 2006 was very dry for most parts of Texas as a whole. For the most part, a very aggressive seeding approach was taken over Uvalde County during the year due to the drought that was classified as severe to exceptional across the area.

At the conclusion of the 2006 operational season for the Authority EAA target area, October 31st 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 2006 seeding season are on the following page.