You may not need a Bottom drain, but run a pond side by side with one that doesn't have one and you'll find that once they are operating correctly, the maintenance is more on the pond without. I stayed away from Bottom drains for many years, when I finally decided to take the plunge I still was very slow about getting it hooked up to a filtration system. Once I did, the water quality is greatly improved, the bottom seldom has any collected muck as it's constantly removed. Two years running and I've never had a issue with it clogging, However, consideration needs to be thought about how to block it off or be able to get to and service as needed should be addressed ahead of time. my pond is shallow enough I can walk across the pond without my head going under water, so with waders I can get in the pond and service even in cold water. Also I made a tool that allows me to remove the cover and replace it f it does clog without having to take a plunge.