Since the spring is constant, those tanks will fill up, and when they do, the overflow comes back down the mountain and through that first food forest underground right to here. This smaller pipe is the overflow from those tanks. The larger pipe is from the floor drain in the barn. When the duck pond, which is about four to five feet deep, fills up, it will overflow over the embankment here and flow down into the food forest area to irrigate the crops.
It's called a duck pond because, when the owners decide they're ready, they'll get some ducks in here, and their poop will add nutrients to the water that'll mix in. When that overflow happens, it will not just irrigate with nutrient-rich water from the duck pond.
There will also be overflow that leaves through a pipe, below grade and over to three different swales in other areas of the food forest. Here are the incoming and outgoing pipes one of the outgoing pipe comes down to this second of three swales. Swale number three has a feeder pipe only, and it's overflow will run over its embankment and feed and fertilize and irrigate the crops below it.
This the southern food forest and its fertigation system in this area. It doesn't really matter whether the owners put the ducks in there or not, it's at least an irrigation system. With the Ducks in the pond, the nutrients will help these crops grow, live and produce better for generations to come.
It's all part of the self-reliance, self-sustaining Permaculture farming approach. It's a beautiful thing, and I know these owners are real excited to get get going start living off the land.