| Numerous articles discuss the merits and shortcomings
of the Geormorphic Stream Classification System developed by Dave Rosgen
(1985). This article discusses the Feather River Coordinated Resource Management
(FR-CRM) group's experience using this system in the FR-CRM watershed restoration
program.
Rosgen first exposed the FR-CRM to the classification
system in 1988. The system has been revised since then (1994), as should
be expected with any new technology. The FR-CRM, a 21-entity consortium
of public and private agencies and landowners, was formed in 1985 and began
an ambitious program of geomorphic watershed assessment and channel restoration.
Beginning in 1990, Rosgen was frequently involved with the group as a project
designer and a trainer of local resource professionals in geomorphic restoration
techniques and classification system use. The groups active restoration
professionals accepted the classification system as a common language in
referencing channel conditions throughout the 3,222 mi Feather River watershed
that contains virtually every streamtype described by the system.
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The classification system provides for a 4 level hierarchy
in river inventory. The most commonly used component of the system incorporates
Level I, geomorphic characterization, and Level II, morphological description,
to identify fluvial geomorphic characteristics that typify a channel's
current
condition (class). When these inventories are completed, reaches are assigned
a single letter/single number classification (B2, F4, E6, etc.). This information
allows assessment of the channel's present stability/instability, past
conditions, and probable trend if left undisturbed.
The nature of the geomorphic assessment also provides
insight into possible habitat improvement or restoration alternatives using
the channel and valley characterization provided by this system. Data intensive
Level III, stream condition assessment, and Level IV, field data verification,
inventories are then performed to analysis flow regimes, sediment loads,
size distributions, debris, watershed condition, hydraulic geometry, vegetative,
and biological data. Upon completion of the 4 inventory levels, specific
design alternatives can be |
