Culverts enable wetland managers to control the water depth inside the impoundment. Standard water control mechanisms include riser boards and flap gates which block the inflow or outflow of water. Several riser boards slide into a slot at the culvert mouth. Individual boards can be added or removed according to seasonal water depth objectives. Similarly, flap gates can be propped open, clamped shut, or left loose to flap open with the influx of water from the estuary. Culverts are typically capped on the impoundment-interior side, but culverts capped on both ends provide for better water control capabilities.

     To do this, they need to know what time of year each avian group has need of the wetland, what their water depth and food resource requirements are, and how these specifications dictate management practices. For effective and practical management, it is helpful to have some baseline data on habitat selection by different species, species population sizes, prey availability, and of course, knowledge of weather patterns at a particular wetland area (e.g., a refuge).

Wetlands managed for shorebirds should be kept shallow, no deeper than 10 cm for the larger species. This is necessary due to physical size constraints (body height, leg length) and foraging techniques (for example, probing and gleaning).

Management should limit vegetation cover so that the habitat remains relatively open for improved ability to detect predators. Locations targeting shorebirds should provide an adequate prey base for migrants, so soil substrate properties and colonization potential (e.g., culverts open for immigration of invertebrates) should be taken into consideration. Many refuges hold water deep throughout the late summer, into fall and winter for waterfowl. The water is then drawndown in late winter, around the time that waterfowl begin migrating out and shorebirds start to arrive.