QA-OB-2: My drive went into an OB pond which is surrounded by tall reeds. One meter from where the disc was last in-bounds puts me in the middle of the reeds. Can I just go back to the tee?

Yes. Going back to the previous lie is one of the OB options. Alternatively, you could declare an abandoned throw with the same result. You can also take optional relief back along the line of play (without it costing you an additional penalty throw) because you would be taking optional relief following a penalty for out-of-bounds. That is probably your best option.