Exam 2 Flashcards
Who was Lowdermilk?
An early soil conservationist who was active in the field of soil protection, land reclamation, flood control, and is known for his work on the National Water Carrier of Israel.
What event in the U.S. inspired Lowdermilk to undertake his travels?
The Great Depression and the Great Plains drought of the 30’s which culminated in the Dust Bowl.
What is the difference between the reach length and a longest flow path?
Reach length is node to node on a stream.
Longest flow path (LFP) is the stream path that extends the furthest watershed boundary from its node outlet.
2 primary forces that control water movement in soils?`
- Gravity
2. Capillary action
What are the 3 possible fates of water at the outlet of a variable source area?
- End up in a stream or lake
- Groundwater recharge
- Evapotranspiration
A closed elevation ring on a topographic map represents what landform on a hill slope?
Summit
Lowest part of the floodplain?
Slackwater
For x=0.0
Outlet is a lake
For x=0.5
Inflow = Outflow Hydro
For x=0.2-0.22
Urban areas
Define catena
Subset of a landscape having hydrologic interconnectivity of landforms
Define landscape
A portion of Earths surface with recurring patterns of geology, soils, topography, climate and hydrology
Define Landform
A portion of a Catena with a common microclimate, hydrology, biology, and soils
Define Soil
A 4 dimensional body that bears the record of the processes which have and are occurring at the location
Soil Forming Factors
- Climate and Bioata modified by
- Geology and Topography
- Over Time
Define Variable Source Area
Part of the watershed that provides supplies base flow to perennial stream. VSA’s lie below the shoulder of hillslopes near ephermal drainages and in hillslope concavities. Dependent of precipitation, evapotranspiration, and soils
5 functions of soil
- Medium for plant growth
- Water supply and purification
- Recycling system for nutrients and organic waste
- Habitat for soil organisms
- Engineering medium
Define Streams
Conduits that move water from areas of higher elevation to areas of lower elevation. The stream dissipates energy.
Define Source
The beginning of the stream.
Ex: lake
Define Mouth
The outlet of the stream.
Ex: Lake, another stream, ocean
Define tributary
A smaller stream that flows into a larger stream
Define Distributary
a stream that splits from its main channel into two or more channels, usually in a delta
Define a Delta
The region near the mouth of the stream. Name after the shape of the nile river mouths in egypt
Define Thalweg
Line along deepest part of the channel
Define Main Channel
Portion of the stream that conveys water when the stream is not in flood
Define Meander
A loop in a stream that dissipates energy by increasing the distance that water must travel along its course
Define Oxbox
Meander that has been cut off from the main channel
Define Floodplain
The area adjacent to the bank that can be inundated during high flow events
Define Natural Levee
The highest part of the floodplain directly adjacent to the bank
Define Slackwater
The lowest part of the floodplain and often the part of the floodplain most distant from the main channel
Fr<1
Subcritical
Fr>1
Supercritical
Fr=1
Critical flow
