水茅（学名：Scolochloa festucacea）为禾本科水茅属下的一个种。

Scolochloa is a genus of grasses in the family Poaceae / Gramineae, now containing a single species, Scolochloa festucacea. Common rivergrass is a common name for the species. Scolochloa festucacea grows in Europe, temperate Asia, and North America. Its culms are erect and 100–150 centimetres (39–59 in) in height; its leaf blades are 15–30 cm (5.9–11.8 in) long and 5–10 mm (0.20–0.39 in) wide.