FRESHWATER WETLANDS

 

I. Distribution

A. Wetland ecosystem distribution; wetland types in North America

B. Losses

C. Kunze classification system, lowland western Washington

II. General techniques for restoring wetlands (National Research Council 1992. Restoration of Aquatic Ecosystems; Science, Technology and Public Policy. National Academy Press, Washington, D.C.)

A. Reestablishing river flow

B. Restoring flood regimes

C. Halting drainage

D. Reestablishing topography

E. Controlling contaminant loading

F. Reestablishing biota

III. Steps in creating and restoring wetlands (D. Hammer 1992. Creating Freshwater Wetlands. Lewis Publishers, Boca Raton, 298 p)

A. Defining objectives

B. Site selection and evaluation

C. Project planning

D. Construction activities

clearing and grubbing

excavation

grading

transporting and placing fill

compacting

placing sand, gravel or rip-rap

installing liners

placing and tilling sealing substances

disposing of waste, excess fill

installing water control structures, piping

installing electrical equipment, other utilities

(planting vegetation)

(seeding)

(mulching or sodding disturbed areas)

IV. Plant selection and planting (M. Stevens and R. Vanbianchi. 1993. Restoring Wetlands in Washington; A Guidebook for Wetland Restoration, Planning and Implementation. Washington State Department of Ecology Publication 93-17, 110 p, Appendices.)

A. Specifications

tables relating species with inundation depth, duration, season

substrate

sources

storage

B. Planting

seed bank

propagule type

densities, spacing, dimensions of material

floating

tree seedlings

protection

post-planting water level management

V. Prairie pothole example (Susan Galatowitsch and Arnold van der Valk. 1994. Restoring Prairie Wetlands; an Ecological Approach. Iowa State University Press, Ames, 246 p.)

A. Seasonal wetlands; as much is farmed as possible

B. Reestablishment of species accomplished by 5 basic methods:

donor seed bank

innoculating with donor soil

seeding: stage 1, stage 2, stage 3

wild hay

transplanting

VI. Water level management example (M.W.Weller 1994. Freshwater Marshes; Ecology and Wildlife Management, 3rd ed. University of Minnesota Press, Minneapolis, 154 p.)

A. Simulating natural processes which may have been lost

B. Requires water-control structure

C. Drawdowns may be complete or partial

1. Complete drawdowns if there is total loss of central vegetation

draining

timing

duration

reflooding

managing for vegetation regrowth

2. Partial drawdowns if there is a decline in vegetation or wildlife

reduce to meadow-depth

lower in late summer

raise to normal water level in fall

D. Artificial methods

basin deepening

islands