Final Test Compilation Flashcards
What use do holding ponds serve in a watershed?
Stabilize water flow. Act as a storage system until water is fed back into the main stream.
Movement of water actually has allot to do with soil. Explain why this is and indicate which texture of soil holds more water. mkay?
Since water that hits the earth is stored and moves through soil we have to know how it effects water. Most soils have around 40 - 50% pore space so there is allot of space for water to occupy.
Fine textured soils like silts and clays tend to hold more water and are more susceptible to mass wasting and slope instability issues when exposed to high volumes of water.
Explain in detail the effects of rain on snow.
eg. how does it effect drainage?
- infiltration?
- mass erosion, debris channels and culvert blowouts
Rain on snow can be problematic because it adds large volumes of water that in some cases exceed the capacity of culverts and even natural stream formations, resulting in high turbidity and habitat degradation. Rain on snow also causes increased erosion of soil substrate which does not infiltrate the frozen soils and carries the sediment and debris into streams.
How can rain on snow events be avoided?
Sustainable methods include harvesting areas that are susceptible to rain on snow events over long periods of time so that the canopy creates a buffer zone and the natural processes that allowed the forest to grow in the first place can be maintained.
Another method would be to simply reduce or decide not to harvest rain on snow sensitive areas
What is the basis of the BC stream classification system?
-2 main conditions
Channel width
Use by fish at any time throughout the year
What is the biggest factor in road degradation?
Precipitation
especially usage during precipitation events!!!
This might be an old question but these are fair game on the test
What is the adiabatic lapse rate?
Adiabiatic lapse rate refers to the rate at which air cools as it rises
it is roughly -6.5 degrees per 1000m
How does a sedimentary bedrock composition effect water movement?
Sedimentary rocks are porous and create channels for water to permeate. They get tilted due to plate tectonics which results in the movement of subterranean water in and out of watersheds.
What are 2 things that influence Basin Geology?
Bedrock composition
Water location and flow
List some drainage patterns
There were 5 listed in the lectures… mkay?
- Dendritic
- Parallel
- Trellis
- Angular
- contorted
Give 3 examples of stream types and briefly differentiate.
Perennials
-flow throughout the year due to ample groundwater and precipitation inflow. Usually found near the bottom of slopes and are fed by multiple smaller tributaries.
Intermittent
-Flow for at least one month per year in response to seasonal runoff. Usually mid slope
Ephemeral
-Do not flow year round due to inadequate precipitation and groundwater availability. Usually upper slope, small streams
What is alluvium?
material that has been transported by running water. Very coarse, rounded material due to loss of loss of most clay/silt fraction downstream.
What two soil qualities heavily influence infiltration, percolation and storage of water that hits the earth.
Depth of soil
Soil texture (Bulk density/Porosity)
what two terms are used to describe the depths of soil?
Hint: based on thickness…
if you don’t think this relates to hydrology feel free to skip this
Blankets - Deeper than one meter
Veneers - Less than one meter (rocky outcrops)
What is an indirated soil horizon and how does it effect water movement?
Also what color is it?
what conditions make it possible?
Indirated soil horizons are red and are the result of water evaporation which causes oxides and other minerals to be deposited as the water moves upward. Creates a restrictive layer that stops water from permeating it.
It is a result of seasonal changes in the water table
In what case will water not infiltrate soil? What is the result?
If the soil is frozen or fully saturated, water will not infiltrate it and will instead cause “overland flow” which leads to mass erosion, stream flashiness and sedimentation.
What is viscosity? What important process does it effect?
Viscosity is a measure of a fluids resistance to deformation and changes in response to temperature.
It has an effect on infiltration of soil by water. The warmer the water the better it will infiltrate a soil.
Explain field capacity
When soil has been saturated and left for 2 days, how much water is left in its pore space.
Basically equates to the water available to plant life.
Whats the PWP?
Permanent Wilting Point
Point at which no water is left for plant life
what two properties of water contribute to Field Capacity?
Adhesion and Cohesion
What does stream gradient refer to?
The slope of stream. During a transect the gradient would be recorded at every station.
What are some shapes that stream gradients can take?
Hint: there were 6 listed in the lecture but the last 3 are just combinations of the first 3… mmmkay?
Concave (thicker soils) Convex (thinner soils) Straight Concave convex Convex concave Concave straight
How is the shape of a stream determined?
What does it effect naturally? industrially?
Largely a function of bedrock geology, glaciation and erosion
effects bank stability, groundwater flow, road location and harvesting methods.
How can you define alluvium in a stream bed?
Coarse rounded material
Different vegetation complex than land above
What is the basic definition of a stream?
A natural water course having an alluvial channel and consistent banks.
What is a stream reach?
A section of stream with repeating characteristics
ex. pool, riffle etc.
As long as the pattern is constant the reach can be as long or as short as those conditions last… mkay?
