I was assigned this question, although it is out of my area of expertise. I suggest
you contact the Oregon Department of Fisheries and Wildlife (link below). They
have programs for habitat and wildlife improvement and can probably answer your question and may even be able to assist with implementation.
Another resource to consider is the US department of agriculture, natural resources conservation services (link below).
Waterfowl love areas that have many aquatic plants ranging from water lilies, tall grasses, and berry bushes. Native plants would be best to plant in and around your pond to prevent the spread of invasive species. Some species you could consider planting would be Duck Potato (Sagittaria laifolia), Water-cress (Rorippa nasturtium-aquaticum), Slough Grass (Beckmannia-syziganche), Cattail (Typha latifolia), and Salmonberry (Rubus spectabilis) to name a few. These plants will provide and attract food sources, create cover from predators, and nesting areas for future generations of waterfowl. You could also go to your local pond shop or contact the Oregon Department of Fisheries and Wildlife to get recommendations for other non-invasive plants to help attract more waterfowl to your pond.