Tpwd does most stockings in public lakes and community ponds. Google to figure out the nearest tpwd fish hatchery to Alvarado lake, give them a call to determine what state biologist is over Alvarado. The guys at the hatchery and usually even the biologist are happy to talk to the public.
In some cases letting them know there's a community of cat fisherman on the lake that would like to see them stocked can get the ball rolling. In other cases the lake has been determined not fit for a certain species like bluecat, so it's a waste of state money to stock them. If you say according to surveys they "don't last", this could be the issue with no stocking.