Hello Lori,
Well, I,ve been holding off saying anything, because I didn,t want to be the guy to throw a monkey wrench into your plans --- But, knowing how that fan assy you are useing is constructed -- I seriously doubt it will work for you !!
A really quick test, would be to put a stick or 2 X 4 against that pulley and I bet you could stop it from turning, pretty easily --and you are going to need torque to spin any kind of generator !!
BUT, don,t be discouraged -- it could be modified to work better by adding some flat plates from some of the outer blades, to the inner shaft -- forming a simple paddle wheel !!
That won,t be the best design for this use, but will add power to it thru shear weight of the water !! BUT, one drawback I see is, being emersed in the stream, will cause the "back" of the blades, to push water -- this will rob some of your power ....Lifting it up, out of the stream, will help a lot !!
I wish I were a little more knowledgeable about computers -- I would draw you a picture and send it to you -- BUT, I,m old and dumb and it,s surprising that I can even manage email!!
Don,t know where you are located, but if you and your husband are anywhere near Washington state, I would be glad to come and take a look ( with my fishing pole, of course !!) and a drawing of something that "might" work !!
Ghurds idea for a gen, might do that part, but your turbine needs more work first and some of the other guys may come up with a better idea -- I remember seeing some turbines on this forum, just for water, you might try looking back thru the archives -- But , most were pretty complex !!
ONE question -- do you always have this flow of water, or will it deminish in summer
Above all, don,t be discouraged -- keep working --My best to you, Bill H....