I am curious if any experienced pond builders out there have principles they use to guide the construction of small ponds? (by small we're talking anywhere from 4 - 10' diameter)
More details - We have a less than 1 acre market garden in Coastal Southern California nestled amongst 3 swales planted with lines of fruittrees (see attached Google Earth shot). As part of our efforts to increase the species diversity and thus resilience of our market garden operation we have created habitat zones bordering most of our market garden paddocks - our attempt to create patches of pollinator habitat, shade, wildlife forage etc. amongst our no-till annual vegetable raised beds. We would very much like to add some sort of perennialwater element to bolster these habitats - something to lets the bees, butterflies and birds come and drink, to give dragonflies an opportunity to thrive, and hopefully entice some frogs up from the creek lower on the land into the market garden area.
Our soils are heavy clay, we are in USDA zone 8b/8a (last winter low was 26, can get down to 22), low/non-existent summer rainfall but with a semi-consistent fog cycle. Lots of sun in the market garden currently and regular diurnal winds - up canyon in the afternoon and gently down canyon at night.
Our current vision - we have automatic irrigation on all of our veggie "paddocks" and will be installing some pressure activated drains on the lines to help prevent bursting when we get into frost season. This means on a regular basis we will have a few gallons of water slowly draining from our irrigation lines, which we would love to put into a water basin of some sort. We have looked at just burying a stock tank, but we feel this would eliminate many of the benefits a more natural water body would provide the landscape - sloping sides, better access, less embodied energy, slow-but-steady hydration into the surrounding soil etc.
I'm specifically looking for input on 1) how small can we go? , 2) how can we manually seal a small water body? (we have pigs, but they're dangerous near the market garden...), and 3) species ideas or guild construction principles for reducing evaporation from wind and sun? And of course anything else that you think is important to consider that I have not listed here.