Northern Prairie Wildlife Research Center
In the past, governmental reclamation agencies have relied heavily on planting design techniques dependent on exotic plant materials to achieve simplistic goals of erosion control, environmental tolerance (e.g., drought or flooding tolerance, soil tolerance, browsing tolerance), and aesthetic improvement (Dawson 1984). Today, use of exotic plant materials still is entrenched in riparian projects. But the use of native riparian plants should be expected to increase as more managers realize the value and ecological diversity that native riparian systems offer. Perhaps the largest influence on riparian design philosophy has been a new attitude among the general populace and increasingly among environmental designers toward management of public lands. This new attitude places less value on engineered landscapes and more emphasis on the aesthetics of native landscapes (Dawson 1984). This is especially true in the West where native riparian plant communities provide a landscape pattern to otherwise homogeneous rangelands and biological diversity to largely evergreen forestlands. The traditional "garden" design of engineered landscapes is being replaced by the native riparian landscape.
Reclamation and re-creation of landscapes after drastic disturbance, such as phosphate mining, requires an understanding of the interplay between physical characteristics and ecological organization (Gross and Brown 1987). General design principles of reclaimed riparian ecosystems are acquired through systematic study of natural landscape organization. Gross and Brown (1987) studied general basin parameters (slope, stream length, percent hydric soils, watershed area) and vegetation types of 12 first order streams in Florida to design reclamation schemes for various types of streams.
Recently, planners have used the services of landscape architects to enhance the native character of the created or restored site, fitting the built landscape into the natural design of the surrounding area. Landscape architects on the Tangipohoa Scenic River Project, Tangipohoa Parish, Louisiana, were involved from the initial right-of-way planning through the pipeline maintenance phase (Abbey 1988).
Design objectives of relocating a segment of Beaver Creek due to construction of the Plaza Lodge in Avon, Colorado, identified the need to redesign the stream channel to provide visual and physical access to the stream; create flat, ponded areas; and restore native vegetation and stream habitat (Tupa et al. 1988). To address design objectives, a design team, consisting of a landscape architect, a hydrologist, and an ecologist, was assembled. The landscape architect was involved with aspects such as visual analysis, site conditions, pedestrian concerns, developer's ideas, and planting plans. The hydrologist provided input on sediment load, meander frequency, channel flood levels, channel design, control structures, and water features. The ecologist provided advice on vegetation types, habitat conditions, wildlife and fisheries, habitat treatments, and construction plans.
Information needed for an adequate engineering design for the restoration Of a gold-mined section of the Blue River near Breckenridge, Colorado, included drilling wells to monitor groundwater levels, establishing stream measuring stations, collecting sediment transport data, and surveying existing channel and adjacent rockpiles (Roesser 1988). From observation of the existing channel and accounts of historical behavior, it was obvious that the system in its existing condition was highly unstable. The design consisting of reducing channel slope, installing drop structures, and constructing localized areas of bank protection was the most economical and aesthetically pleasing alternative.
Highway construction projects may involve relocation of a portion of a stream or river. Design of these relocated sections should follow natural, high quality sections of the stream. In highly degraded streams, designing a more stable stream channel may be prerequisite to reestablishment of channel bank and floodplain vegetation (Jackson and Van Haveren 1984). Especially important is assessing the direction of the disturbance from the geomorphic norm and determining both the probable cause and current watershed conditions. A disturbed channel is an effect of watershed conditions, and the conditions causing the disturbance must be corrected or the design will most likely fail. Channel design involves duplicating the geomorphic characteristics of the more stable channel reaches in the same physiographic setting and making necessary modifications for sufficient bank stability to promote vegetation.