Couderay River is considered a Coldwater, Deep Lowland, Cool-Cold Headwater, Two-Story, Impounded Flowing Water, No Classification, Warm Mainstem under the state's Natural Community Determinations.
Natural communities (stream and lake natural communities) represent model resultsand DNR staff valiation processes that confirm or update predicted conditions based on flow and temperature modeling from historic and current landscape features and related variables. Predicated flow and temperatures for waters are associated predicated fish assemblages (communities). Biologists evaluate the model results against current survey data to determine if the modeled results are corect and whether biological indicators show water quaity degradation. This analysis is a core component of the state's resource management framework. Wisconsin's Riverine Natural Communities.
Warm Mainstem waters are moderate-to-large but still wadeable perennial streams with relatively warm summer temperatures. Coldwater fishes are absent, transitional fishes are common to uncommon, and warm water fishes are abundant to common. Headwater species are common to absent, mainstem species are abundant to common, and river species are common to absent.
This classification includes waterbodies created by dams (mill ponds, reservoirs, flowages, and other impoundments) with a residence time of 14 days or more
(under summer (June – Sept) mean low flow conditions with a 1 in 10 year recurrence interval (US EPA 2000)). Many natural lakes also have dams or water level control structures. However, to be included in the Impounded Flowing Waters category, the dam or water level control structure, must account for more than half of a waterbody’s maximum depth. Impoundments with a residence time of less than 14 days should be covered under the rivers and stream assessment methodology process.
Shallow headwater lake describes the depth and location of the lake in a watershed. These variables affect the lakes response to watershed variables.
Deep lowland lake describes the depth and location of the lake in a watershed. These variables affect the lakes response to watershed variables.
Cool (Cold-Transition) Headwaters are small, usually perennial streams with cold to cool summer temperatures. Coldwater fishes are common to uncommon (<10 per 100 m), transitional fishes are abundant to common, and warm water fishes are uncommon to absent. Headwater species are abundant to common, mainstem species are common to absent, and river species are absent.