Simpson’s 1969s Sci Fi movie ref...

 I think it references West World with Mr. Brenner. That is an iconic film.

You need to think hard and research some things- color or black and white, any actor or actress names, character names? 

Thanks for the reply dk!  I've seen original movie West World a couple of times back in the day, and I watched the entirety of the chase scene much more recently just looking for this scene.  But I'm quite sure the Simpson's river scene is not from WW (original or new series).  In the movie (or perhaps Sci Fi series - I've poured through Outer Limits episodes too looking for this), the robot chasing the protagonist acts like a robot - stiff walking and all - and heavy enough to not be swept away while walking under the river.  The movie/episode was black and white. I believe it was also raining in the scene.  I was like 10 years old (so that's over 40 years ago) when I saw it and of course recall no actors or character names.  All I have is the incredible, haunting image of the 'unstoppable robot'* pause briefly at the downed-bridge, and then walk slowly, determinedly down its bank and under the water to reappear on the other side, devoid of emotion and determined to catch its pray.   *In the Simpson's chase scene, as Skinner emerges from the river, Bart says something to the effect of "...he's like some kind of non-giving up school guy..."  I've searched ad nausea using terms like "unstoppable..." thinking that phrase was a clue to the scene's origin - but no luck so far.

A bit more detail... The original scene was in and 'older' movie or episode.  So I"m thinking the original is of late 50's or early to mid 60's  origin.  And I"m not sure, but I think it took place on another planet and the protagonist is trying to get back to his spaceship. I'm far less certain of these details as I am of the river scene -which is indelible. 

Anther curios soul: https://ask.metafilter.com/241684/Did-Yul-Brynner-walk-into-a-river-in-Westworld