DIY trenchless technology -- what options would be suitable?
Thought about making your own? PVC conduit run from an excavation deep enough to go under to another hole deep enough to retrieve. Attach fittings to allow you to use water pressure through the conduit itself to hydraulically bore the hole? Then blow the water out with air, attach fittings, and fish your wire. I have done this for both conduit and water pipes (albeit never 30' across).

You could glue pipe pieces as you go to facilitate ease of insertion and operation. Think male threaded adapter with adapter to water hose thread (or fire hose thread, on a grand scale), as pipe proceeds you cut off and glue the next section, reusing your fittings each time.