Trousers (Advanced): Below The Rippling Waters

Head to the Lakeside Hut, and wade through the muddy waters to the southern part of the expansive lake, heading roughly northeast, toward the relatively small island just off the shore line.

Turn and face south once you’re on the small island, and optionally use your Witcher Senses to find the orange glow of a chest just below the water’s surface on the southern bank of the island.