are you sure it's only 100 gallons of water you need to move? that's less than half a cubic meter of water, or are you saying per day you'd need to take that much load off. If your not going that far an extension cord for the outdoors isn't unreasonable so you could run a lower input pump for longer. I use an
energy hog pump that couldn't be run on
solar and it takes me an hour to fill a cubic meter tank = to 250 liters. That last me about 1 week in the
greenhouse if it doesn't get any rain water off the roof. You could do it over longer with a smaller hose but solar is going to bite the dust on you in overcast weather without a battery store. if you can put in swales you most likely could build a 500 gallon
pond in a day, and put multiple ponds along the back of the swales allowing you to slow the run down and store more for the drought. Dig a pond a weekend and in a month you could be holding much more water than you could manage to recycle by pumping it back up over an over when it's already wet. Pumping back up is not bad for trying to give the water another chance to infiltrate, maintenance of drip irrigation along the swale isn't worth it unless you had a large storage you were dripping from uphill all through the dry season. What you'd get out of more ponds/ mega micro dam is allot of micro climates, sun reflector's, increased humidity and water storage you could syphon down onto the lower swale makes the manual digging a minor input with a much greater output of multiple benefits. Throw a few feederfish into the ponds and you'll have no mosquito issues, and you have spots to stick aquatic plants in the summer. Even in my
lawn I have dug holes and placed bathtub's in them in no time at all, just to add another water source for ducks, frogs, fish and plants.