Bullfrogs can also occasionally be found inhabiting urban areas near ditches and culverts. Ruts prevent rainwater from flowing to the side of the road into ditches or gutters. These use irrigation ditches or farm ponds to raise fish. Bodies were piled high and blood flowed like rivers in the ditches and trenches. Some artificial larval habitats are barrels, sewage ditches, and intermittent puddles. These marshes are criss-crossed with drainage ditches. The Janissaries dug in behind ditches and two palisades. Farmers plowed and planted seeds in the fields, which were irrigated with ditches and canals. Fields are generally large and bounded by drainage ditches. They were unable to dig the customary ditches or trenches around the fort. These fences are combinations of banks, logs, water, ditches and other elements. One such example was the maintenance of agricultural drainage ditches. Many unofficial crossing points were blocked with ditches and barricades. Many populations can be commonly found growing near drain ditches and bayous in Houston, Texas. It has two deep defensive ditches and ramparts.