ERE 412: Final Exam

River corridors are complex, __,__ and when minimally altered with fluxes of energy, water, and material across __ dimensions

dynamic; heterogeneous; 4

(T/F) The Rosgen river classification type D is a multi-threaded channel; these are common to river deltas, where sand is a common substrate and dune ripple patterns can form.

false

Match the Rosgen river classification letters with the Montgomery and Buffington classification words. When uncertain, make the most likely matches and match the remainder.

B- plane bed

D - dune riffle

C - pool riffle

A- cascade or step pool

\n Albert Einstein had worked some on settling in sediment suspension, and was known to ___ his child to work sediment transport, thinking it was ___ and ___.

discouraged; difficult; intractable

\n Potential uses of data from established permanent river channel reference sites that use trusted river measurement techniques and classification:

Monitoring trends in fluvial and geomorphic condition over time

Assessing stream and watershed response to management or impact

Providing channel and flow facts for water allocation

Supporting resource inventories (habitat

Allowing valid comparisons based on stream type

restoration

reestablishing structure and function of ecosystem

\
Returning degraded ecosystem structure and function holisitically, and as closely as possible, to pre-disturbance levels.

rehabilitation

making ecosystem useful after disturbance

\
Returning degraded ecosystem structure and function to some new use supporting the natural mosaic.

reclamation

changing biophysical capacity of ecosystem

\
Returning degraded ecosystem structure and function to some new use supporting human needs.

Approximately how many miles of rivers are there in the US?

3\.5 million

\n Sort the order which Montgomery and Buffington river types (classes) are likely to follow, from mountain top to ocean bottom:

Cascade

Step Pool

Plan Bed

Pool Riffle

Dune Ripple

threshold

not easily mobilized by the stream design flow

alluvial

continuously or frequently reshaped

\n In our lecture, what percentage of US river and stream miles did not support healthy aquatic life due to stressors such as nutrients, poor vegetation, degrading banks?

50-60

River system key variables number up to ___, but with only ___ governing equations known and ___ variables fixed by site conditions, rivers are considered ___ systems.

13; 3; 6; indeterminate

\n Sort the 8 major variables used to classify river systems in the order listed in our course lecture and the USDA FS (C. Harrelson) text.

width

depth

velocity

discharge

slope

roughness of bed/bank

sediment load

sediment size

(T/F) \n River classification measures form and makes inferences about processes, presuming rivers with similar classifications act in similar ways.

false

shear stress equation

Tao = Gamma \* R \* S, where Gamma is specific weight, R is hydraulic radius, S is longitudinal slope

river power equation

Omega = Gamma \* Q \* H, where Gamma is specific weight, Q is discharge, H is hydraulic head available

(T/F) \n Based on the NRCS Chpt 1, the hyporheic zone of the river corridor is the unsaturated interstitial area below the river channel where surface and subsurface waters mix.

FALSE

If you take a BS = 5.24 ft to a BM with an ELEV = 100 ft, the HI = ___.

\n

105\.24 ft

\n Based on the NRCS Chpt 1, threshold channels have ___ fixed variables and ___ independent variables than alluvial channels because their ___ does not change.

more; fewer; form

If you complete a differential leveling circuit with a total distance = 350 ft, for your survey closure assessment the allowable error is ___ or = ___.

(T/F) \n Based on the NRCS Chpt 1, scientists often misinterpret river corridor processes across space and time because they usually study pristine systems - those already cleared of large woody debris, dammed, channelized, leveed, or constrained by other hard structures.

FALSE

\n According to the USDA FS Stream Channel Reference Sites, 2 meander lengths is approximately ___ bankfull widths in length.

20

Based on the NRCS Chpt 1, organize these river and watershed restoration actions from largest to smallest temporal and spatial scale:

Native fisheries recovery

\
Decreased erosion sedimentation from road improvements

\
Riparian fencing to reduce hoof-shear

\
Instream improvements to create habitat

Based on the NRCS Chpt 1, initially river or fluvial ___ were inferred based on river or fluvial ___; we now know ___ are needed to predict the behavior of river corridors.

processes; forms; process-based approaches

\n According to the USDA FS Stream Channel Reference Sites, a river station with the value 0 + 75 is at ___ feet along the river ___.

75 ft; centerline

\

\n Based on the NRCS Chpt 1, an idealized process-based conceptual model is the ___ which describes changes in ___ alluvial channels undergoing ___ incision.

incised channel evolution model; straightened; headward

\n During a profile survey of the thalweg, with the station at a fixed location and the rod at a fixed length, your FS measurements are getting ___ so the ELEV should be getting ___. The person on the rod is likely moving downstream.

larger; lower

\n Based on the NRCS Chpt 1, no perfect river model exists, but they may be useful by showing the ___ changes in a river corridor when ___ treatments are considered.

relative; alternative

lateral dimension

width of the river corridor

longitudinal dimension

length of the river

vertical dimension

depth of the river corridor

\n If you take a BS=4.00 ft to BM1 with ELEV = 100 ft, and a FS = 6 ft to TP1, and then move your station and take a BS = 3 ft to TP1, your HI = ___.

101 ft

If you take a FS = 3.12 ft to a TP with a HI = 94.76 ft, the TP ELEV = ___.

91\.64 ft

If you take a FS = 5.24 ft to a BM with an unknown ELEV, the HI = ___.

not able to be computed

(T/F) Based on the NRCS Chpt 1, dynamic metastable equilibrium posits the physical characteristics of channels remain relatively constant during long period and undergo rapid changes during short episodes when the system exceeds some internal threshold.

TRUE

(T/F) The reading on a survey rod by an auto level will be too small if the rod is tilted and not vertical; at vertical the reading is accurate.

FALSE

According to the USDA FS Stream Channel Reference Sites book, the average discharge fills about 1/3 of the channel and is reached or exceeded only ___ % of the time. Please note, average is not the same as median when the shape of the variable's distribution is skewed rather than normal; discharge tends to be skewed.

25

\n Based on our discussions, rank the following channel features from most to least difficult to identify in a braided river with flowing water.

thalwag

edge of water

bankful depth

bankfull depth

thalwag

edge of water

\n Bankfull discharge is synonymous with ___ and ___, the flow that transports the ___ amount of sediment in the long-term under current climatic conditions.

effective discharge; channel maintaining; largest

\

\n Luna Leopold and Reds Wolman consider bankfull discharge to occur about every ___ yrs or less. Erosion, sediment transport, and bar building by deposition are most active at discharges near bankfull. Floodplains are formed by lateral migration of rivers during meander bar building and cut-bank erosion.

2

the floodplain ___ flow width and constrains the rate which flow depth and hydraulic radius increases. Hydraulic radius is a major driver of the flow's ___.

does not; increases; boundary shear stress

\

bankfull indicators

.

Top of point bars

\
Change in perennial to annual vegetation

\
Change in channel bank side slope

\
Change in bank materials

\
Bank undercuts

\
Stain lines

\n The USGS Bankfull Discharge and Channel Characteristics of Streams in New York State estimates BKF width = ___ feet (to 0.1 places) for a drainage area = 65 square miles in Region 7. Please use the regression equation for regions in Figure 1, rather than reading the graph for a value.

73\.1

The USGS Bankfull Discharge and Channel Characteristics of Streams in New York State estimates BKF depth = ___ feet (to 0.1 places) for a drainage area = 65 square miles in Region 7. Please use the regression equation for regions in Figure 1, rather than reading the graph for a value.

3\.4

The USGS Bankfull Discharge and Channel Characteristics of Streams in New York State estimates BKF cross-sectional area = ___ square feet (to 0.1 places) for a drainage area = 65 square miles in Region 7. Please use the regression equation for regions in Figure 1, rather than reading the graph for a value.

245\.8

The USGS Bankfull Discharge and Channel Characteristics of Streams in New York State estimates BKF discharge = ___ cubic feet (to 0.1 places) for a drainage area = 65 square miles in Region 7. Please use the regression equation for regions in Figure 1, rather than reading the graph for a value.

904\.2

\n The USGS Bankfull Discharge and Channel Characteristics of Streams in New York State estimates BKF width = ___ feet (to 0.1 places) for a drainage area = 65 square miles in Region 5. Please use the regression equation for regions in Figure 1, rather than reading the graph for a value.

88

\n The USGS Bankfull Discharge and Channel Characteristics of Streams in New York State estimates BKF depth = ___ feet (to 0.1 places) for a drainage area = 65 square miles in Region 5. Please use the regression equation for regions in Figure 1, rather than reading the graph for a value.

3\.9