I have a 1/4 acre pond that was completely covered in a thick layer of duckweed and mosquito fern. There are lots of posts on the internet reporting speculation that trash pump removal might work but not to many direct reports.
Recently I was able to essentially clear my pond of duckweed with a very cheap (cheapest amazon.com sells) 2 inch semi-trash pump. Just wanted people to know that this is an option for duckweed choked small ponds.
Before and after pictures attached.

Good information.

Hope I never need it!

That looks great! Did you use something to concentrate it into one area, then pump it out? How long does the surface stay clean before the duckweed comes back? Did you do/use anything else on it or just pump it from the pond?

I did not have any large boom to skim the entire pond. I mostly waited on the wind to be of assistance. I used a pcv intake setup (picture attached) zip tied to a metal stake in the corner of the pond. The pvc wye with a ball valve constantly under the surface helped maintain pump prime.

At first the duckweed was incredibly thick. I would just put the trash pump on low throttle and let it slowly skim off of the surface. Once it had thinned out some i waited for the wind to help me. I used some 4 inch landscape boundaries (visible in the first post pictures) as small booms to sweep the remaining duck weed into the intake.

No chemicals were used. I may consider using if the duckweed returns which it probably will. It has only been a few days since the after picture. The duckweed was so thick I feared using any herbicide would cause a DO crash.

Similar size pond, same coverage of duckweed. How did you separate the duckweed from the liquid and did you return the water to the pond (California is water-challenged!)? I have not used a trash pump before, but I think the idea makes sense once I figure out the collection of the massive amount of unwanted weeds and how to filter the water back to the pond. Any advice is welcome.

Many duckweed species have an alternate reproductive method using turions (sinking seeds) that stay in the mud bottom until light penetrates at which time they rise and start the process over. You have to stop the entire process.

I directed the trash pump output into an area where the water would flow back to the pond. Use a silt fence to block the duckweed. You will have to move the duckweed manually then, but it is a lot easier once it has dried.

I fully expect it will return. I hope that...

1. The hopefully decreased nutrients from removed duckweed
2. Tilapia have spawned so hopefully they can keep up with it.
3. Now i will feel more comfortable with some targeted herbicide applications.

Will keep the problem manageable

Keeping the water stirred up (aeration / pump/wind etc. )will help. If the DW is constantly turned over it tends to die.