Monocacy Battlefield has a number of streams and a river that traverse its landscape. The largest is the Monocacy River, which flows through and along the boundary of the park and is a tributary of the Potomac River. There are also three small streams that are tributaries of the Monocacy River. Bush Creek flows through the Gambrill Farm area, Harding’s Run flows through the Baker Farm and around Brooks Hill, and an unnamed tributary flows through the Thomas Farm.
Due to the size of the Monocacy River and that much of the park is in the floodplain, the visitor center and surrounding fields are often flooded. This flooding has caused some damage over the years to the foundation and electrical wiring within the visitor center, as well as damaged crops in the nearby fields.
The small, unnamed tributaries located in the battlefield are intermittent or seasonally inundated. If buffered with vegetation, these small streams may offer water quality benefits to the receiving Monocacy River which will, in turn, affect the entire river system downstream. The park is currently developing a water quality monitoring plan to ensure the health of our waterways.