Sle 231- Hydrology And Water Resources Management

Front 1

What is river channelization and how can a stream respond?

Back 1

Channelization is the channel engineering for flood control, drainage improvement, maintenance of navigation, and erosion prevention.
-can cause degradation which moves upstream as a kickpoint, aggradation downstream may cause channel incision + bank instability.
-any change causes a knickpoint and induces a response by stream
-steeper slopes have
caused bed movement and bar formation, channel
widening and braiding

Front 2

Briefly describe the relationships between stream depth, velocity, and bed particle size in a pool-riffle OR pool-step sequence

Back 2

-a pool is a region of deeper, slower moving water with fine bed materials where a riffle is a region with coarser bed materials and shallower, faster-moving water.
-riffles cross sectional have square shape where pools have more asymmetrical profiles
-riffles have coarser bed material and higher width:depth ratios than pools

Front 3

What is the role of these bedforms (i.e. pool-riffle sequence and pool-step
sequence) in providing habitat for stream organisms?

Back 3

-p. 185 gordon
-young fish and small fish tend to inhabit riffles where as deep pools with overhanging banks and vegetation support larger fish. During low flows, riffles may be exposed and pools can become isolated pockets of water which allow the survival of aquatic organisms.
-most productive streams have a combination of pool sizes propose that the reason biodiversity is greatest in the middle of streams is because they typically have a pool-riffle morphology

Front 4

What affect does coarse woody debris have on banks and beds?

Back 4

Woody debris, bedrock, construction,
root-defended banks may stabilize
locations of bars (affecting downstream currents and backwater effects)
-Placing obstructions in channel may
cause formation of bars
-Bars may become attached to bank and eventually become part of floodplain

Front 5

importance of soils

Back 5

- hydrology
-engineering
-agriculture, food fiber
-geology
-raw material
-mining

Front 6

composition of soils

Back 6

-mineral particles
-organic material
-water
-air
-biota

Front 7

soil formation

Back 7

-parent material
climate
topography
-organisms
time

Front 8

watershed

Back 8

boundary line, marks a dramatic change in environments

Front 9

ISC

Back 9

Index of stream condition- take into account stream beds, stream banks, and instream beds, erosion and sedimentation, instream physical habitat, and connectivity

Front 10

bank stability indicator

Back 10

stable, limited erosion, moderate erosion, extensive erosion, extreme erosion

Front 11

importance of hydrology for river ecology

Back 11

river flow is essential to the ecology of river systems

Front 12

mesoscale

Back 12

-point where management focuses, flow regime at a single point (mesoscale) on river shows

Front 13

parent material (down a slope)

Back 13

alluvium
colluvium
aeolian
glacial
wind
ice
water

Front 14

colluvium

Back 14

material that accumulates at the food of a steep slope

Front 15

great barrier reef affected by erosion

Back 15

(sugar cane farming) global warming, tourists.

Front 16

soil erosion (main mechanisms)

Back 16

gravity
-soil creep, mass movement
water
-rainfall (when it exceeds absroption)
wind

Front 17

brown and red soil

Back 17

brown- more organic material
red- more erodible (sand)

Front 18

alluvium

Back 18

-deposit of sediment (clay, silt, and sand, gravel) left by flowing streams in a river valley or delta typically producing fertile soil

Front 19

Three main mechanisms for soil erosion

Back 19

-gravity (soil creep, mass movement)
-water( erosion occurs when rainfall rates exceeed absorption rate of soil)
-wind (more pronounced in areas with decreased vegetation curves)- can transport soil km away

Front 20

Vegetation and gravity affect on the thickness of the A horizon

Back 20

A is thicker downslope in a valley, A horizon is thicker in the presence of vegetation

Front 21

What are the A, B, C layers of soil

Back 21

A- top soil (rich in organic matter)
B- little organic matter
C- bedrock, cracked + weathered

Front 22

A horizon

Back 22

mixture of organic and mineral material, lost some of original materials to leeching

Front 23

O horizon

Back 23

surface layer of plant materials in varying stages of
decomposition not significantly mixed with the mineral soil;
may not always occur.

Front 24

Horizons in Forest (highest slope) (high in vegetation)

Back 24

-A is thinnest
-B is thickest
-C is slightly less than B

Front 25

Horizons in Grassland (middle slope)

Back 25

- A and B are equally thick
-C is the thinnest (very tiny)

Front 26

Horizons in Desert (lowest in slope) (no vegetation)

Back 26

-A is super thin on top
- B and C are thickest (equally)

Front 27

Horizons highest where on slope?

Back 27

A s highest in grassland (middle), and smallest in Desert
C is thickest in desert, and thinnest in desert (no veg and low slope)

Front 28

Briefly describe the role of headward erosion in river valley lengthening.

Back 28

-knickpoint formation allows for new streams to form by channel widening, deepening and slope lowering, erosion of tributaries

Front 29

Based upon what you now know, why do you think the study of physical
form (bed and banks) is important in the assessment of river health?

Back 29

study of bank flow allows for flushing flow, (banks help determine maintenance flow). Flow alteration has major impacts on aquatic ecosystems and is a focus of river health assessment.

Front 30

bifurcation ratio

Back 30

the ratio between the number of successive orders
(number of stream segments in given order/ number of stream segments in higher order).
(number of streams in one order, and the number of streams in the next highest number).

Front 31

braided streams

Back 31

-interlacing network of channels separated by coarse alluvium