First picture is pennywort, 2nd, 3rd and 5th look like water willow, also looks like you have some pickerel weed (purple flowers) mixed in. 4th picture looks like creeping/water primrose (does it have yellow flowers?)

that's a tough mix you got there, if you're interested in a mechanical option give me and Annamarie a call down here at the Lake Mower company here in San Marcos.

If at first you don't succeed...look in the trash for the directions.