Ponds require more structure than being a hole in the ground with water in them; they are eco-systems. Fresh water ponds exist in deserts as well as rain forests; and all require the same basic structures. Using the extreme in the high Arizona desert as an example, I will briefly describe how to construct a pond.
Water is the essential ingredient and the most overlooked. You require an adequate source (solar electric pumped from a natural aquafer in pic). It must be of high quality or you will have a weed infested mucky mess. Therefore, you must design the pond to accept an ecology that will keep the water healthy.
The design is from the bottom up. The bottom should slope (1:3) to a deep hole (12 feet) near the outflow. This leads to proper respiration. The shape of the pond should be irregular. Entire edges on shorelines result in wave action. When the shore is irregular, there are no waves resulting in a turbulent surface with low shear force to reduce evaporation of your water (as in pic on windy day).
Fractured soils on mesas (in pic) and on hills or mountains require liners. Ponds do not exist in such places. Ponds exist in sedimentary basins usually with layered clay millions of years in the making. The reason clay cannot seal a pond on a hill is the water flows into the pond through the fractures in the winter and out in the summer. Pond liners can be completely hidden and consist of poly-vinyl chloride (PVC) coated fiberglass fabric. They are origami folded at the liner company to easily unfold at the job site (six people unfolded the one in the pic; ¼ acre). A planting shelf needs to be placed under the liner to allow securing of the liner. Do not forget to ballast the bottom with rock or the liner will float up.
A river run round rock shelf (< ¾ inch) is constructed completely around the pond to act as bottom substrate for invertebrates and a planting bed for water plants. This shelf is about two feet deep perfectly level to the water surface. The surface of the shelf is used to plant slough sedge (Carex obnupta) and as a place to put a rotting deciduous log (pond food). I call this a pond engine because it takes care of the respiration and heat transfer in the pond; it does the work.
Trees and willows can be planted on the south, east and west side of the pond to provide a canopy (see foreground of pic with drip system). Trees are extremely important because they are “what is”. All natural waterways have them. Trees provide cooling for the pond and habitat.
Adding some fishes and crayfish establishes the basics for pond ecology. Providing nectar bearing flowers and seed plants to attract birds and insects completes the system. Frogs and turtles will come and soon you will have a functioning ecology. Add a chair for the top predator mammal: you. This makes for a closed system where Mother Nature can easily fill in the gaps. If you fulfill this much, the rest follows.
Unfortunately, froggie your house is often nothing but a hole in the ground with water in it, the pond standard. It is easier to set-up a forever pond that requires no care. The resulting system is complex but is constructed with nothing more special than a few plants, dead log and some rock. Keep it sweet and simple (KISS); and you can have an oasis in the desert for a plunge on hot days. Thank-you, Andrew, for showing us your PonDoc pond in the desert.
With the kindest of regards; yours always,