The only thing that will help is another pond that has better habitat. Some people have installed propane cannons set to fire at some interval that will scare those birds away, although there are reports that they get used to that after a time, too.

I hate to say this, but your problem is normal. Ducks and geese will want to spend much of their time on land, eating tender grass shoots, insects, garden plants, etc. Most places that have populations of these birds live to regret it. At least in those locations where the bird and human environment are in close proximity.

People that build those large water features as an amenity and don't understand how ducks and geese will use it are creating a real problem for the property owners. As you well know. Adding another pond will likely add to the problem rather than mitigate it.

Well, there are a number of spray on repellents that you should try. They will work for awhile. You should also use scare tactics such as imitation reptiles (large), in combination with the repellents. I think that motion activated sprinklers would help, too. The noise and water would startle them.

In my city, there is a small lake built within the campus of one of the universities. Ducks and geese pretty much took over the location, creating a health hazard and ruining the landscaping and grass. Repellents worked for a while, as did a remote operated car used to chase them all over the place (hilarious). But the thing that has really helped is the installation of three large alligator decoys that float all year long in the lake. They are secured to the bottom with weights and chains. The population of birds on that lake has been greatly reduced! (Not eliminated, but reduced.)

Type in 'goose repellent' into google and do some reading. I think that with a combination of simple things, you can keep the ducks and geese away.

May I recommend a dog? Even if the dog does not actually catch any of the birds, it can chase them away. (If it does catch one occasionally, look at the birds as free dog food.) You should probably check to find a breed that has the interest and enthusiasm for chasing. Some dogs will learn to tolerate intruders.

Renais

I'd be willing to bet a bunch that black-vette lives in a community with a leash law.

At my workplace trained border collies are used to keep the geese out away from the lake and out of the roads. The dogs herd without barking and do not injure the birds.

It has worked very effectively in training the birds to not congregate on the site.

A customer of mine had had enough. He grabbed his .22 revolver, waded through a few inches of duck and goose poop, and started blasting away, at point blank range, until the gun was empty.

He was amazed by his poor marksmanship since, none of these flying rats were showing any signs of injury.

His son had loaded the revolver with blanks while training their retriever. The birds were evidently traumatized enough by the incident. Now, they eat and poop all over all of the other neighbor's yards and docks. But, they stay clear of his place.

I also bet a pretty lil Jack Russell Terrier or Rat Terrier would do a fine job of "protecting" you and yours. It's what they love doing!

Me, I'd make sure there was real bullets in the revolver.

Try some tinsel, I had the same problem on the dock with ducks, laid down some foil(was advised to put tinsel) seems to work for now.
Might need to change it once in a while (different colors). They seem to be scared of it.