Bio RIvers & Lakes Exam 1

Cascade Reach

Steep slope, disorganized/tumbling streambeds, large sediment, large particles rarely move

Step-pool reach

Steep terrain, large sediment, small pools alternate with steps, act like dams

Plane-Bed

intermediate gradient, long, flat, gravel/cobble sediment

Pool-riffle reach

Intermdiated gradient, midsize stream variable sediment, erosion + deposition create structure

Braided reach

higher order stream, variable/steep gradient, sandle/gravel sediment, multiple channels

Dune-ripple reach

low gradient, small particles, rapples, waves, sediment always moving

Stream segment

specific portion of flowing water between 2 sources

stream reach

speciifc length of a river/stream

pool

area of slow flowing deep water, often on the outside of bends

riffle

fast, shallow flow over boulders and cobbles which break the water surface

run

smooth, unbroken flow, connecting riffles & pools

thalweg

bottom or lowest points in cross-sectional area of a stream

hyporheic zone

area where groundwater interacts with surface water

colluvial

shaped by gravity dumping hillside debris directly into water

alluvial

segments are shaped by water itself moving & sorting its own sediment

perennial stream

flowing all the time

intermittent stream

flowing some of the time and receiving

ephemeral stream

flowing rarely and not receiving input from groundwater

Lentic

non flowing or slow flowing open body of water in a depression that is not in contact with the ocean

pond

waterbody surface area less than 2 hectacres

lake

waterbody surface area more than 2 hectacres

large lake

water body surface area 50,000 hectare

reservoir

waterbody behind a dam

tectonic lake formation

formed by movement of earths crust

glacial lake formation