Biddle Street, Yatton (grid reference ST423648) is a 44.8 hectare biological Site of Special Scientific Interest (SSSI) near the village of Yatton in North Somerset, notified in 1994.

Management practices and the variation in the soils has resulted in the watercourses supporting a wide range of aquatic plant communities.

Where open water occurs plants such as Common Water-starwort (Callitriche stagnalis), European Frogbit (Hydrocharis morsusranae), Fan-leaved water-crowfoot (Ranunculus circinatus).

The calcareous influence of the underlying Compton soils also encourages Whorled Water-milfoil (Myriophyllum verticillatum) and Stonewort (Chara sp).

Also present are the nationally scarce Rootless Duckweed (Wolffia arrhiza) and Hairlike Pondweed (Potamogeton trichoides).