[2] During his time in Seguin, Wirtz became involved in a group interested in developing the Guadalupe River as a source of hydroelectric power.

Wirtz provided legal assistance to the Insull holding company Emery, Peck, and Rockwood as they built a chain of privately owned dams and hydroelectric projects on the Guadalupe River.

In 1932 Wirtz was assisting the Emery, Peck, and Rockwood firm in a similar project on the Colorado River when the Insull empire collapsed.

To complete the dam, Wirtz promoted the creation of the Lower Colorado River Authority (LCRA).

Wirtz was the Austin lobbyist for many oil and natural gas companies, who coordinated the successful lobbying against the New Dealer Leland Olds re-nomination for the chairmanship of the Federal Power Commission.