As part of The Outer Banks of Virginia, the refuge's barrier islands feature large sand dunes, maritime forests, fresh water marshes, ponds, ocean beach, and large impoundments for wintering wildfowl.

They are stocked in dozens of large impoundments to control baitfish populations and provide sport for anglers.

Water released from the bottom of dams on such large impoundments is about 40 degrees at this time of year and from 45 to 47 degrees in summer.

Equally adaptable to large, cool-water impoundments and reservoirs, the smallmouth also spread far beyond its original native range.

It can withstand temperatures below 10 C and is mainly found in stagnant water, muddy dams and in large impoundments.

The barrier islands feature large sand dunes, maritime forests, fresh water marshes, ponds, ocean beach, and large impoundments for wintering wildfowl.

Skipjacks are no longer found in high numbers in the northern reaches of their distribution because of their inability to migrate over large impoundments.

There are also two large impoundments on Dell Creek.

Located in central Massachusetts, the Quabbin, one of the largest domestic water-supply impoundments in the country, was created to provide water for the Boston area, which by 1920 was exhausting its reservoirs.

It prefers sluggish, mud-bottom pools and backwaters of rivers and streams, and does well in lakes and large impoundments.