Yes it's a beautiful area - our own little slice of native New Zealand bush. The slope continues down some way unfortunately, so it's there or nowhere.
The water source will be trucked in (pricey!) / rainwater collected from our property, there's no other option unfortunately.
If you are using a pond liner, why can't you go nearly vertical for the pond side slope of the dam? That would help your geometry considerably. Just spoil your excavated material downstream of the pond liner location.
This is exactly the info I'm looking for thanks! Everything I had read has suggested a 1:3 slope on the water side - but reasons ranged from ease of exit to decreasing chance of water leak. My concern (seeing as in am lining it) it simply dam strength. Does the strength only come from the non-water side and crest width, or does it come from the water side too? Ideally, seeing as I'm lining it I'll go for a steeper uphill slope and the problem will be solved.
Down hill I cant see a way I can get steeper than 2:1 with an earthen dam. I'll plant it with lomadra which has a super strong root system to minimise the chance of slippage.
