Ok so here is my idea take a brigs and Stratton pressure washer mount it on a trailer (yes it is gas powered Reliable, easy starting Briggs & Stratton® 500 Series™ engine (158cc) )
Put the water exit into a pipe mount a turbine drive system on a shaft between the wheels the and make a return hose into the a water tank that has a coupling that goes into where you have the water going in to the system. so you reuse the same liquid!
AND AWAY YOU GO!!!!!