I doubt this is true, not with 127 vehicles already IDed with sonar. Most all the cases will be "cold" missing person cases, but there are probably many tens to hundreds of people who've been living with the idea that, "Jonny's alive somewhere, he just up and left us broke'......since 1978. Except "Jonny's" been underwater the whole time, in a worm-eaten Dodge Dart.
The Houston police should get special funding to do this, but they should do it. Given the size of their force, they must have grant-writers who could apply for coverage.