HF012

Attribute: UNIT_DESC

code		description
CASC		A channel unit with a very high-gradient, characterized by white water tumbling over bedrock or boulders. Boulders generally not organized into channel spanning steps.
DAM		Pool caused by a dam, blockage, or other feature raising downstream water surface.
FALL		Small (<2m), but distinct, channel-spanning waterfalls caused by cobbles, boulders, bedrock or wood oriented perpendicular to the channel axis.
GLIDE		A channel unit that is run-like, except that flow is not noticeably concentrated toward the center or thalweg.
HGR		A riffle that is relatively steep (slope 4% - 7%), often with large cobbles or boulders present in clusters, but not organized into steps or ribs.
PLUNGE		A pool formed below a step by spilling, or plunging water.
POOL		A channel unit with a low or very low gradient, areas of slow tranquil flow, a well-defined depression in the bed, and relatively shallow water at the downstream end.
RAPID		A channel unit characterized by, swift, very turbulent water, often flowing over and around large boulders.
RIFFLE		A channel unit characterized by moderate gradient (slope < 4%), and swift, but relatively shallow water flowing over substrates of mixed size that are often only partially-submerged. Flow is moderately turbulent and
RUN		A channel unit that is pool-like, except that velocity is greater, shallow water at the downstream end is lacking, and flow is noticeably concentrated toward the center or thalweg.
SCOUR		A pool formed by the deflection of current (by an outcroppings, boulders, or wood), causing a scoured depression. Often associated with a well-defined re-circulating eddy.
TRENCH		An elongated pool in a narrow section of stream; often associated with bedrock outcroppings.