Board Members

Photo of Bereket M Derie PhD, PG
Professional Member
Work P O Box 13225 Austin TX 78711 Work Phone: (512) 936-4400

Biographical Info

Bereket M. Derie, PhD, PG, of Round Rock is a licensed Professional Geoscientist and Chief Executive Officer with Round Rock Geophysics. Prior to that, he was the Geophysics Department Manager at Renewable Resource Consultants. He is a member of the Society of Exploration Geophysicists, Engineering and Environmental Geophysicists Society and Austin Geological Society. Dr. Derie received a Bachelor of Science in physics and Masters of Science in geophysics from Addis Ababa University in Ethiopia and a Doctor of Philosophy in geophysics from Loughborough University, UK. His term is set to expire February 1, 2021.

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Photo of Steven Fleming PG
Professional Member
Work P O Box 13225 Austin TX 78711 Work Phone: (512) 936-4400

Biographical Info

Steven Fleming, PG, of San Antonio is a licensed Professional Geoscientist and the Environmental Supervisor for Apache Corporations’ North American Unconventional  Resources region. He is a member of the Permian Basin Petroleum Association, New Mexico Oil and Gas Association and Society of Texas Environmental Professionals. Fleming received a Bachelor of Science in biology from Sul Ross State University and a Master’s of Science in limnology from Baylor University. His term is set to expire February 1, 2021.

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Photo of C. Thomas Hallmark PhD, PG
Chairman, Professional Member
Work P O Box 13225 Austin TX 78711 Work Phone: (512) 936-4400

Biographical Info

Charles Thomas Hallmark, PhD, PG, of Hearne is a Professor Emeritus in the Texas A&M University Soil and Crop Sciences Department. He is a former member of the American Registry of Certified Professionals in Soil Science, a current member and past President of the Professional Soil Scientists Association of Texas, and past President of the Post Oak Soil and Water Conservation Society. He is also a past member of the Soil Scientists Certification Board, the American Society of Agronomy, and the Soil Science Society of America.  Hallmark served in the U.S. Army. He received a Bachelor’s degree from Texas Technological College, a Master’s degree in Soil Science from Texas Tech University, and a Doctorate of Pedology from Ohio State University.  Currently, he is serving a second appointment to the Board, and his term is set to expire February 1, 2019.

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Photo of Becky Johnson PG
Secretary/Treasurer, Professional Member
Work P O Box 13225 Austin TX 78711 Work Phone: (512) 936-4400

Biographical Info

Becky Johnson, PG, of Fort Worth is a board certified Professional Geoscientist and Geologist, an Environmental Science Professor at Texas Christian University, and Consultant/Trainer with  more than 26 years of experience.  She is a founding member of the  Society of Texas Environmental Professionals Sustainability Chapter, and a volunteer with the Texas Commission on Environmental Quality EnviroMentor Program.  She served for the last 10 years as past president / officer of Society of Texas Environmental Professionals.   Johnson received a bachelor’s degree in geology from the University of Texas at Arlington and a master’s degree in environmental science and hydrogeology from Texas Christian University. Her term is set to expire February 1, 2023.

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Work P O Box 13225 Austin TX 78711 Work Phone: (512) 936-4400

Biographical Info

Drusilla Knight-Villarreal of Corpus Christi is a retired teacher. She is an emeritus member of the Board for Coastal Bend CASA – Court Appointed Special Advocates. Knight-Villarreal received an Associate degree from Del Mar College, Bachelor of Science in political science, speech, and secondary education from Texas A&I University, and a Master of Science along with other state teacher certifications in specialized areas.  Her term is set to expire February 1, 2019.

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Photo of Lindsey Lee
Public Member
Work P O Box 13225 Austin TX 78711 Work Phone: (512) 936-4400

Biographical Info

Lindsey Lee of Edna is owner of L2 Cattle Company, a realtor with Twin Rivers Real Estate, Vice President of the Jackson County Farm Bureau, and a member of the Edna Lions Club. She is treasurer of the Jackson County Cattle Raisers Association, member of Jackson County Farm Bureau and the Texas Farm Bureau’s Natural Resource Committee. She is a board member of the Texana Arts Council, volunteer with Helping Hands of Jackson County and member of both the Texas Community Futures Forum Group and Jackson County 100 Club. In 2015, she was named Jackson County Rancher of the Year. Bradford received a Bachelor of Science in political science from The University of Texas at Austin. Her term is set to expire Feb. 1, 2021.

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Photo of W David Prescott II PG
Vice-Chairman, Professional Member
Work P O Box 13225 Austin TX 78711 Work Phone: (512) 936-4400

Biographical Info

W. David Prescott II, PG, of Amarillo is president of Talon/LPE LTD. He is a member of the Texas Association of Professional Geoscientists and Texas Food and Fuel Association, and a Board Member of the Amarillo Tri State Exposition, Boy Scouts of America Golden Spread Council and West Texas A&M University Engineering and Enterprise Center Advisory Boards. He is a past Board Member of the Amarillo Chamber of Commerce, Don Harrington Discovery Center, and Texas Panhandle Chapter of the American Red Cross and West Texas A&M University Alumni Association. Prescott received a Bachelor’s Degree in Environmental Science and Master of Business Administration from West Texas A&M University. His term is set to expire February 1, 2019.

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Photo of Brandon Stowers
Public Member
Work P O Box 13225 Austin TX 78711 Work Phone: (512) 936-4400

Biographical Info

Brandon Stowers of Austin most recently worked as account executive for an Austin based information technology firm. Stowers received an Associate of Arts & Sciences degree in biology and social sciences from Weatherford College and a Bachelor of Arts in corporate communications from Baylor University.  His term is set to expire February 1, 2023.

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Photo of Mark Varhaug, PG
Professional Member
Work P O Box 13225 Austin TX 78711 Work Phone: (512) 936-4400

Biographical Info

Mark Varhaug, PG, of Dallas is vice president and senior geologist at DeGolyer and MacNaughton, with over forty years of experience in the practice of geology. He is a life member of the Society of Petroleum Engineers and a member of the American Association of Petroleum Geologists, Geological Society of America, and the Geological Societies of Dallas, Houston, and West Texas.  Varhaug received a Bachelor of Science from Southern Methodist University.  His term is set to expire February 1, 2023.

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