Final - Surface Water Flashcards
Define Wetlands
Land where an excess of water is the dominant factor determining the nature of the soil development and the types of animals and plant communities living at the soil surface. It spans a continuum of environments where terrestrial and aquatic systems intergrade
Define Marshes
Wet most of the time. Grassy or reedy. Can be salty (tidal) or fresh. Shallow. Most common wetland in N.A.
Define Swamps
Woody plants, often treed. Deeper water (>1m). Shrub and forested swamps. Nutrient rich.
Define Bogs
Water from precipitation, mostly. Thick mat of vegetation (peat) rather than soil. Often acidic. Soft, spongy, organic
Define Fens
Like bogs, but fed more from surface water or groundwater. More nutrients, higher pH. Often associated with glacial kettles.
Which three countries account for the most peat stock, and therefore carbon storage of this source type?
- Canada, 2. Russia, 3. Indonesia
Which three countries account for the largest emissions from peat degradation?
- Indonesia, 2. Russia, 3. China
How much of canada is covered in peatlands?
12%, or 1.2 x 10^6 km2
How much of Canada is covered in wetlands?
14%, or 1.4 x 10^6 km2
How much of global wetlands occur in Canada?
14%
Which provinces account for the majority of Canada’s wetlands?
Ontario, Yukon, Manitoba
How many lakes are there in Canada?
> 32,000
What is the largest lake in the world and how much of global lake water does it account for?
Lake Baikal, 20%.
How much of Canada’s area is freshwater?
8.9%, 891,163km2
What constitutes laminar flow?
Re less that 500
What constitutes turbulent flow?
Re greater than 2000
What factors influence river velocity change?
- shape of channel
- input
- surface characteristics
- slope
What is a downfall of a stilling well?
Being automated, it’s subject to errors if not routinely checked
What are three methods of measuring discharge?
- Velocity-area method
- Tracer Dilution method
- Float measure method (surface only)
What are two tracer dilution methods?
- Constant
2. Dump
What are some advantages/disadvantages of the tracer dilution method?
Advantage: useful in turbid waters where meters can be damaged
Disadvantage: must consider stagnant water, vegetation, water movement
What two things does hydrograph character depend on?
- Precipitation characteristics (magnitude, intensity, duration, distribution, phase)
- Basin Characteristics (slope angle, slope shape, soil type, soil thickness, initial soil moisture conditions, anthropogenic impacts, basin size, basin shape)
How are unit hydrographs used?
Use type of precipitation event to predict discharge/flooding conditions
What are the three mechanisms of fluvial transport?
- Advection
- Diffusion
- Dispersion
Define Advection
Movement of tracer resulting from the current (mean flow of water)
Define Advective Flux
Amount of tracer transported per unit time, per unit area perpendicular to current
Define Diffusion
Tracer mixing and spreading from random molecular motion within fluid
Define Dispersion
Mixing due to velocity gradients in fluid (shear dispersion)
How can solute tracers be lost?
- temporary storage
- decay or sorption of solute
What are the two methods of quantifying stream order?
- Strahler
- Shreve
What 6 factors influence overland flow?
- Precipitation intensity
- Snow melt rate
- pre-existing soil saturation level
- soil type (hydraulic permeability)
- Ground cover
- Topography/terrain characteristics
Under what two conditions does surface runoff occur?
- Infiltration excess overland flow (unsaturated soil, infiltration can’t keep up)
- Saturation excess overland flow (saturated soil, no room for infiltration)
Define Interflow
Lateral movement of water through the unsaturated zone
Define Artificial Recharge
Practice of artificially increasing the amount of water entering a groundwater reservoir
What is artificial recharge used for?
waste disposal, secondary oil recovery, land subsidence problems, water resource management
Define Flooding
a rising stage level associated with excess discharge in response to storms or seasonal melt
Why is it useful to understand flooding?
- land-use planning and zoning
- insurance
- infrastructure design
- floodplain delineation
Define bankfull
threshold stage before river flows over banks
Define mean annual flood and how often does it occur?
breaches channel banks onto floodplain every 2.33 yrs (P = 43%)
What are the three methods of flood prediction?
- Hydrographs
- Recurrence Interval
- Rational Method
Why is BC subject to some of the largest floods in NA? (4)
- rain on snow melt events
- autumn and winter frontal rains
- spring melt or “freshet”
- heavy summer rains (convectional and frontal)
