How to Design A Permaculture Pond For Your Edible Landscape delves deeply into the aspects of creating a permaculture pond, in general, sans the details about carving out a sustainable home for free-ranging your food forest ducks. 

A ledge or a slope. I went with a ledge for most of my own duck pond as I want to maximize the amount of water the pond can hold. This will also give ducks a place that is technically still in the water where they can rest, without swimming, if they need to stay a bit cooler during the summer heat. They enjoy standing on this ledge to bathe and preen on warm days as they still have full access to the water to keep their feathers wet during this process.

This ledge should also be heavily planted in order to avoid erosion and to give the ducks some cover from sun and flying predators like hawks. In an unlined pond, your ducks are going to eat the sides of the pond where the ground is soft, moist, and muddy, this is called drilling. They are looking for bugs, grubs, and plant roots to gobble up. 

You can protect your ledge and pond sides from your greedy water fowl by adding a layer of rocks or pea gravel to the pond edges. 

More Tips On Designing A Duck Pond:

Designing A Proper Duck Pond, from Land Vista Aquascapes

Well, that depends on how you're planning to seal and maintain your pond. Though the general rule of thumb is that it is easier to sustain a pond ecosystem on a larger body of water. This does not mean that it is impossible to do with a smaller pond as a pond ecosystem can also be achieved in a pond with a liner, a converted swimming pool, or even a kiddie pool.

A deeper pond also gives you more space to grow more plants for not only your garden ducks, but for you to harvest, if you're willing to go in there to get the food. It is also useful to have a deeper pond if you are planning to stock your pond with feeder fish for the ducks because the fish will need to be able to dive down away from the ducks in order for some of them to survive long enough to spawn and make more fish, giving you an endless supply for your ducks to feed on.

Great choices for bog or plants nearby your duck pond include:

-rhubarb

-bamboo

-asparagus

-Japanese Maple Trees

-Phormium

-Blackberries

-Comfrey (nearby but not in bog area)

-Sweet Grass   

-Sweet Potatoes

-Strawberries

Some ideas for marginal (the "ledge") of your pond:

-Sweet Grass

-Taro (edible elephant ear)

-Juncus (Arrows Rush)

-Sedges

-Non-Edible Elephant Ears

It is also important to note that there will likely be plenty of grasses that pop up along the sides and edges of yoru pond. These will also help support the structure of the pond as the plants you add get established and grow in. A lot of grasses are also edible to ducks so it might be worthwhile to leave those grasses in place to keep the sides of your pond stable.

Duckweed and vallisneria (jungle val) are two very inexpensive, fast-growing options. The vallisneria can be planted in the bottom of your pond and allowed to spread on its own. Duckweed grows on the surface of the pond as a floating plant, is high in protein, is easy to grow, and spreads quickly. 

If there is already water in your pond and, like me, you have no intentions on going for a cold swim every time you need to add a plant to the deepest parts of your pond, you can tie each plant to a small rock, aim, and toss it in the general spot that you would like for it to grow in. Something you'll want to keep in mind is that your ducks do not care about whehter or not your plants are established before they start gobbling them up, so in order to prevent your garden ducks from eating your newly "planted" pond plants before they can get to spreading is to keep the water level high on your pond. 

For those who have access to a source of water to fill up the pond, this, of course is easy. Otherwise, this is something you'll want to take care of several weeks before the arrival of your ducks, if possible. 

Although you don't need to "add" common garden weeds like dandelions, ducks have also been known to snack on these too, adding more variety to their diets.

It has been noted by aquarium keepers and in my own experience with trying to get duckweed established in my own duck and fish ponds that jungle val (vallisneria) releases a chemical compound to weed  😬😬😬 out the competition. The competition being... duckweed. What this means is that you cannot grow both vallisneria and duckweed in a single pond unless you plan on flooding the pond on a regular basis (which removes some of the compond produced by the jungle val making it possible for the duckweed to survive). 

I don't recommend this as it can be a lot of additional work, but, there is also the benefit to your plants of being regularly flooded with high nutrient duck or fish water, and as ducks will eat both, duckweed, and vallisneria, it might be worth the effort to pump out the duck water as liquid fertilizer for your plants, or to just flood the system every now and then. 

Also be sure to check out: How To Prepare Your Edible Landscape to Welcome Indian Runner Duck(lings)

Here you can see many of the wetland plants that I recommended, including the sweet potato vines, taro, asparagus, goji berries, and blackberries, which all really took off once the ducks began living outside and using their duck pond on a daily basis. 

I have since added banana plants, golden oregano, ferns, bamboo, hostas, juncus inflexus, beijing grass, and tree collards. Many of these plants are edible for ducks and for people, so it makes use of the duck pond nutrition, acting as a wetland filter to grow more food for the water birds and for me.