Streams and Rivers Practice Flashcards

Fundamentals of Watersheds and Drainage Systems

  • Watershed Definition and Synonyms: A watershed is a land area that channels rainfall and snowmelt to creeks, streams, and rivers, and eventually to outflow points such as reservoirs, bays, and the ocean. It is also known as a:

    • Basin

    • Catchment

    • Contributing area

    

  • Watershed Boundaries: These are defined by drainage divides, which are the high points or ridges that separate one drainage basin from another.

  • Pour Points (Outlets): These represent the specific point on a map where water flows out of a watershed, often the lowest point in that drainage area.

  • Key Components of a Watershed System:

    • Precipitation: The primary input of water into the system.

    • Headwaters: The furthest place in a river or stream from its estuary or downstream confluence.

    • Watershed Boundary: The perimeter defining the catchment area.

    • Wetlands: Areas where water covers the soil or is present either at or near the surface of the soil all year or for varying periods during the year.

    • Floodplain: An area of low-lying ground adjacent to a river, formed mainly of river sediments and subject to flooding.

    • Tributary: A river or stream flowing into a larger river or lake.

    • Hillside: The sloped land leading toward the water body.

    • Bankside: The land immediately bordering the stream channel.

    • Water Table: The upper level of an underground surface in which the soil or rocks are permanently saturated with water.

    • Ground Water: Water held underground in the soil or in pores and crevices in rock.

    • Stream Channel: The physical confine of a river or slough consisting of a bed and banks.

    

Classification and Anatomy of Aquatic Ecosystems

  • Lentic Systems (Still Water): Ecosystems involving standing water bodies, which include:

    • Lakes

    • Ponds

    • Bogs

    • Swamps

    • Marshes

    

  • Lotic Systems (Running Water): Ecosystems characterized by flowing water, including rivers, streams, and creeks.

  • Physical Features of Lotic Systems:

    • Overhead Canopy: The layer of leaves and branches from riverside trees that shades the stream.

    • Woody Debris: Logs, branches, and twigs that fall into the stream, providing habitat.

    • Riparian Zone: The interface between land and a river or stream.

    • Stream Bank: The terrain alongside the bed of a river.

    • Stream Bed: The bottom of the stream channel.

    • Channel: The main path of the water flow.

    • Substrate (Stream Bottom): The material (silt, sand, gravel, rocks) resting on the bottom of the stream.

    

  • The Hyporheic Zone: This is the region of sediment and porous space beneath and alongside a stream bed where there is a mixing of shallow groundwater and surface water. This process is known as Hyporheic Exchange.

    

Geomorphic Stream Habitats and Floodplain Morphology

  • Habitat Zones:

    • Riffles: Shallow, fast-moving sections of a stream where water flows over rocks, creating turbulence and high dissolved oxygen. These are primary Erosional Zones.

    • Pools: Deeper, slower-moving sections of a stream where water is calm. These are primary Depositional Zones.

    • Runs: Intermediate areas connecting pools and riffles with a smooth, rapid flow.

    

  • Vegetation Types:

    • Submerged Vegetation: Plants growing entirely underwater.

    • Emergent Vegetation: Plants rooted in the substrate but extending above the water surface.

    

  • Floodplain and Channel Dimensions:

    • Topographic Floodplain: The broad land area that may be covered by water during extreme flood events.

    • Hydrologic Floodplain: The section of the landscape that is reached by water during common high-water events.

    • Bankfull Width: The width of the stream at the stage where the water just begins to overflow into the active floodplain.

    • Bankfull Elevation: The vertical height of the bankfull stage.

    • Bankfull Depth: The distance from the stream bed to the bankfull elevation.

    • Wetted Width: The actual width of the water surface at a given time.

    

Stream Hierarchy and Flow Categories

  • River System Ordering (Strahler Stream Order): This is a method used to rank the size and nesting of tributary networks.

    • Headwater streams are designated as 1st order.

    • When two 1st-order streams join, they form a 2nd-order stream.

    • When two 2nd-order streams join, they form a 3rd-order stream, and so on.

    • The system can reach 5th order or higher in large river networks.

    

  • Categories of Stream Flow Persistence:

    • Ephemeral Stream: A stream that flows only in direct response to precipitation. The channel is always above the water table.

    • Intermittent Stream: A stream that flows during certain times of the year when it receives water from the seasonal high water table or from a spring. It may be dry during the seasonal low water table.

    • Perennial Stream: A stream that has continuous flow in parts of its bed all year round during years of normal rainfall. Its bed is located below the seasonal low water table.

    

Questions & Discussion

  • Question: In this figure, which watershed are we within at Dalton State?

  • Answer: Based on the regional map of Georgia's 52 major watersheds and the 14 major river basins, Dalton State is situated within the Conasauga Watershed (Basin ID 03150101), which is located in the Coosa River Basin.