Water level sensors for water pump
Just buy a pump with integral float switch (that's the red thing): -

(source: reuk.co.uk)
I use a similar one to this to pump waste water from my koi pond 10m up a slope to a drain. It works but, if you don't value your time enough to spend (maybe) $100 then my advice is useless.
Try searching &quot;submersible water pump with integral float switch&quot;. Of course the 10m depth means you have to possibly refine the search parameters.