Opportunistic Flooding


Managing Wetlands When Your Water Source Is Not Guaranteed

Several landowners have developed shallow water impoundments in areas where a guaranteed source for re-flooding is not available. Under this circumstance, management practices may vary from those where consistent re-flooding capabilities exist.

Several options are possible for this type of wetland management. Landowners must decide whether to de-water the unit to encourage a vegetative response or to hold the water through the year.

Option 1

Conduct a drawdown (as discussed in the moist-soil management section) then allow the unit to re-flood opportunistically in late summer through fall or even winter. Then hold the water in the unit throughout the next year or two.

Under this management plan, moist-soil plant seeds would be available immediately after initial flooding, then invertebrates would be available until the unit is again de-watered in late spring up to two years later.

Option 2

Hold water in a unit from three to five years to encourage emergent or aquatic vegetation.

This technique will provide a lower number of plant seeds, but will still provide an important wetland habitat type for many wildlife species. In this option, food sources would be mainly invertebrates associated with a more stable water system. De-watering every three to five years will allow plant regeneration and encourage nutrient cycling (release of nutrients from organic matter by decomposition, making nutrients available for plant growth).

Once the unit is de-watered, disturb the soil by disking to encourage moist-soil plants to return. After disking, one of the above management options could again be initiated.

Option 3

Manage these units in a moist-soil system.

Following an annual spring drawdown, the unit might remain dry in the fall, but would often refill sometime in the winter or spring. Fall habitat would sometimes be available, but newly flooded habitat would be available in late winter or early spring in most years. These newly flooded spring areas are important and increasingly rare habitats for many migrating birds.

Whichever management option you select, remember that water will not necessarily be available when you want it. You should plan ahead and make the most of the water when it does become available.