Grand Canal is a 9.1 mile stream, with the associated WBID(s): 1968D.

The Grand Canal is a 10 mile-long network of shallow canals that created an expansive waterfront residential community on Siesta Key. Construction first began on the feeder canal from Roberts Bay and the heart-shaped, inner loop surrounding what is known today as Palm Island in 1945 with the onset of residential development. The remaining canals were dredged in the 1950's and 1960's to provide fill for residential lots and boat access to Roberts Bay and ultimately the Gulf of Mexico. Since there is only one inlet to refresh the canal water through tidal exchange with Roberts Bay, the canals farthest upstream in the system undergo limited flushing. There is an advanced wastewater treatment plant that is permitted to discharge highly treated wastewater to the main canal. Although most of the shoreline has been hardened by vertical, concrete seawalls that limit shoreline habitat value, there are some unaltered areas that provide significant mangrove habitat. Wading birds, manatees, dolphins, shellfish, and numerous fish species are commonly seen throughout the canal system.