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Topographic Reconstruction
Mining requires the movement of massive quantities of soil and
rock. In the process, large alterations to the original landforms
(i.e. mountains, valleys, rivers, streams) occur which triggers
an acceleration of natural geomorphic
processes that further degrades the land. The understanding
of this concept originates from nature's desire to maintain a stable
environment where an approximate dynamic
equilibrium exists between geomorphic processes and the natural
landforms (i.e. mountains, valleys, river and stream channels) that
these processes shape. Nature's approximate balance creates an environment
where geomorphic processes change the resulting landforms relatively
slow. When lands are drastically disturbed, geomorphic processes
are rapidly out of balance with the newly altered landforms and
nature tries to rapidly regain a new dynamic equilibrium. As a consequence,
geomorphic process rates are accelerated resulting in land degradation
problems. A major goal of reclamation is to reconfigure the land
in such a way that approximate dynamic equilibrium is restored and
geomorphic process rates are slowed to prevent unnatural degradation
of the land. Attempt is commonly made to restore the landforms to
the way they were before disturbance, although exact replication
is not feasible because reclamation cannot restore some geologic-material
and soil properties.
For proposed mines, it is important to document all land features
in the area that will be disturbed. These features may include:
location, elevation, gradient, aspect, and soil type of all hillsides;
location, geometry, length, gradient, sinuosity, peak flow, and
bed material of all stream channels; locations of stream channel
convergence; locations of different drainage
basins in the area; and peak
discharge and sediment
discharge from each basin. Reclamation efforts attempt to reconstruct
drainage basins, which consist of valley hillsides, valley
head hillsides, spur-end
hillsides, and stream channels.
For more information on topographic reconstruction, see Barnhisel
(2000). Also, check out the following web links:
The Case Histories Section the Mineland Restoration Site gives
real world examples of topographic reconstruction with great pictures
and discussion on specific reclamation projects.
Problem | Compliance
| Health & Safety | Sampling
| Analytical | Data
Quality
Site Assessment | Prediction
| Construction | GIS
| Monitoring & Assessment
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