The study analyzed sediment quality in Nansi Lake over four years. Sediment organic matter, TN, and TP levels were high, with a decline during a drought period. Sediment TP increased while organic matter and TN decreased from north to south in the lake. Laoyun River and Guangfu River had higher levels than other areas. Sediment in the lake region had higher organic matter, TN, and TP than in the joining rivers.