Definitely Eurasian watermilfoil. TPWD probably won't get too alarmed since it is already present in many TX private lakes and several public reservoirs. But, as bcotton mentioned, they'll probably recommend its aggressive management (on your own dime) and advise you of your obligation to avoid transporting it anywhere and in any manner.
EWM isn't terribly difficult to control in small lakes and ponds, assuming static water conditions (no flow-through) and no irrigation occurs from the BOW.

Kelly Duffie
Cypress, TX