As the days get warmer, there are two places nearby that I'd particularly like to recommend: Hillebachsee and Hennesee.
Hillebachsee near Niedersfeld is rather small and quiet – perfect for a short break. Here you can go for a walk, enjoy the sun, or simply sit by the water. The atmosphere is particularly relaxed and pleasantly intimate on warm days. The waterski and wakeboard facility is especially popular, suitable for both beginners and experienced users.
Hennesee is a bit larger and offers more options for a day trip. Whether it's a walk along the shore, a short bike ride, or simply a spot by the water – you can enjoy a variety of activities here throughout the day. The view over the lake is particularly beautiful, always appearing different depending on the time of day.
What I like about both places is that they have very different atmospheres – yet both convey a sense of peace and spaciousness.