Northern Prairie Wildlife Research Center
Rock sills have been used to reform wet meadows drained as a result of stream erosion, brought about by livestock grazing. On Willow Creek in California, grazing had impacted vegetation so severely that gullies 1-2 meters deep had formed through wet meadows and eroded in an upstream direction, changing the moisture regime so that native grasses and other meadow plants could no longer survive (Clay 1984). With loss of vegetative cover, erosion was accelerated and eventually the entire area was converted to bare ground or brush. Slots cut across the channel formed large rock sills that allowed deposition to fill the channel upstream from each sill to its crest, raising the channel bottom and thus the water table. The sides of the channel developed a gentle slope, which allowed wet grasses and shrubs to become established.
In urban areas, stream restoration is an alternative to conventional channelization involving stream straightening and deepening with heavily riprapped banks. On Briar Creek in Mecklenburg County, North Carolina, a channelized stream was restored by removing brush, debris, and dead trees that blocked water flow; sloping banks to less than vertical inclination; sloping meander bends to produce sandbars; seeding banks; and sparingly using riprap along highly erosive slopes (Keller and Hoffman 1976). The result was an esthetically pleasing urban stream with greater wildlife habitat potential and lower flood hazard.
On a relocated section of the South Fork of the Yuba River in California, efforts were made to provide fish habitat by: (1) correcting the ditchlike appearance by meandering the stream as much as possible within the limited area available, (2) sloping and stabilizing stream banks to prevent additional silt from entering the stream, (3) removing silt from the stream channel to provide food-producing and spawning areas for fish, (4) providing shelter for fish, and (5) providing streamside vegetation (Warner 1965). A tree-planting operation improved the appearance of the streambank and provided shade for both fish and anglers.
The need to relocate streams in surface-mined areas is quite common due to the great expanses of land that mines encompass. To better understand how to ensure proper aquatic habitat restoration in mine locations, fish and invertebrate populations were studied at three stream relocation sites: Pipestone Creek, Perry County, Illinois; Otter Creek, Fulton County, Illinois; and Honey Creek, Clay and Vigo Counties, Indiana (Thompson 1984).
Few habitat improvement techniques were used on Otter Creek, although some shale and small gravel was available within the new streambed for habitat development to occur. After 6.5 years, Otter Creek was not comparable in most aspects to the natural channel and appeared to be more sensitive to natural perturbations, such as flooding and drought conditions, than the other relocations.
The Honey Creek site had the most extensive habitat treatment, including creation of meanders, large pools, and riffles, and the installation of wing deflectors, log structures, and random placement of boulders. No extensive riparian tree zones existed along the sites, but they were at least partially shaded and had up to 100% cover. Of the three sites, Honey Creek developed the greatest amount of habitat diversity and showed the most habitat stability resulting in the closest match in species composition of fish and invertebrates with higher quality natural channels.
Traditional habitat reconstruction techniques appear to work well in stream relocations in surface-mined land, but the type and quantity to be included should be based on premine conditions and the anticipated postmine location. In addition, habitat replacement should be tied closely with proper stream channel design and erosion control. Based on results of Thompson's (1984) study, it appears that streams can be relocated and recover to premine conditions if all major habitat components are restored. This is accomplished primarily through proper preplanning and implementation.
Tributaries of the South Prong Alafia River in the phosphate mine district of west-central Florida were reclaimed by creation of ponds and marshes within the stream. Other techniques included transplanting topsoil and planting various woody and herbaceous plants (Robertson et al. 1987). Aquatic invertebrate data from the first several years after reclamation indicated that richness of stream systems reclaimed with marshy areas exceeded that of undisturbed streams, but richness of reclaimed lotic sections matched that of similar undisturbed streams.
Creation of ponds in a stream also was used in the Beaver Creek Relocation Project near Avon, Colorado (Tupa et al. 1988). A segment of the creek was relocated to facilitate construction of a ski lodge. Problems associated with pond construction included minor sedimentation. Detailed manipulation of pond flow characteristics had to be adjusted to ensure that the majority of stream sediment stayed in the channel and did not fill the ponds.
Restoration of a section of the Blue River near Breckenridge, Colorado, involved nearly complete restructuring of the channel (Roesser 1988). The area had been heavily gold-mined from the late 1800's through 1942. Rock and cobble piles reached 30 feet above old channel grades, and most of the river flowed beneath and through the piles. Restoration consisted mainly of removing rocks and cobbles, recontouring the channel, and revegetation. Drop structures were used to create a stable channel. Although considered highly experimental, these techniques appear to be successfully restoring the channel's stability.
In areas of the Mississippi Delta, shallow impoundments have been created to supply soil moisture to bottomland hardwoods that have experienced considerable dieback and mortality due to drought in the 1950's (Broadfoot 1967). Average increase of radial growth was about 50% for all species of hardwoods impounded on an experimental area near Greenville, Mississippi, and subjected to various flooding regimes. Oxygen supply could potentially be a problem in using this technique. However, most artificial impoundments are charged either by rainfall or ground wells within the forest and are relatively free of sediment.