Why not use your new waterfeature to collect and store water for you!
      See the Toprock "Reservoir System" below...

The principal is to better-utilise the waterfeature terrain,
getting it to act as a water-catchment area.

Below is a model of how the System could catch more water for you.

The Toprock Water-Catchment System  makes a beautiful garden, that also gains water for you!

(1) You underlay the entire section of garden that you have allocated for the waterfeature (or even
      further garden area if possible), with a tough liner, and slope the terrain towards your in-ground
      reservoir, to store up to 1500 litres of extra water for the garden.

(2) You can also enlist the catchment of the roof and direct it to the in-ground reservoir as an
      alternative to an aboveground tank.

(3) River stones and plants are laid over the liner, and the entire effect is a natural and pleasing one. 
    You then ordinarily, but not compulsorily!, add a waterfall and stream.

(4) Rainwater is then collected on the liner you laid down in point (1) above,  and directed to your
      reservoir, which is then covered with sleepers or similar.

(5) Mosquitoes are kept out of the tank by a choice or combination of Toprock techniques.
      Leaves and debris washed toward the reservoir are similarly arrested via Toprock techniques.

(6) Even if your waterfall loses water to evaporation, you will have more than enough top-up water
      efficiently caught through your larger catchment area. 
      (You can also use your captured water to green-up the rest of the garden.)

(7) Plants are usually contained in pots and flourish on drip watering, with any unused drip water
       also being collected, since it also trickles down into your reservoir!

(8) You can also supplement your in- ground tank water via roof water, easily and cheaply
       captured from your downpipes and piped to your tank underneath the stones.

(9) Soil dug out to make space for your in-ground tank is subsequently used to slope the
       terrain towards the tank. Your surplus soil can also shape your terrain with hills and dales,
       and you can hold such shapes in position using the (patented) Toprock “Hard-Coat”(TM).