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Subsections
Things to bring:
- a good coat, gloves and hat (if the weather is cold or wet)
- wading shoes or boots, shorts or fast-drying pants (only
needed if the ground is wet or creek is high)
- a field notebook and pen or pencil
Lab equipment: (all equipment except your lab notebook) will be supplied by the TA)
- General
- timer (stopwatch, watch with second hand, etc.)
- floats (for velocity determination)
- field notebook
- High Discharge Conditions
- impeller flowmeter
- measuring tapes and/or taglines
- anchors for taglines (stakes or nails)
- surveyor's tape or marker for marking tag line
- graduated pole or weighted measuring tape (for depth measurement)
- Low Discharge Conditions
- yardsticks (a substitute for tagline)
- rulers (for depth measurement)
Lab2 Parameters to be Measured
Please refer to the textbook (Chapter 3, Sanders, 1998) for a
detailed description of the measurement of each parameter listed
below. In the field, we will break up into 3-4 groups, each group
will be responsible for measuring the parameters listed below at a
station assigned by the TA or professor. We will then move to the
picnic area in the park to discuss data analysis, and compare results.
At this time or later you will write up your laboratory procedures and
results (due at the beginning of the next lab). In your discussion
you will describe your group's results, compare them to those of the
other groups, and explain any observed variation.
Parameters to be measured:
Stream Cross-Section
- measured directly using simple
surveying techniques (Fig. 3.3). Used to determine the
cross-sectional area of the stream, also hydraulic radius and wetted
perimeter (see text p. 53-55).
Stream Velocity
- determined by float method (Fig.
3.7) and direct measurement when possible (impeller velocity meter,
Fig. 3.10 and Section 3.1.3).
Used to compute discharge (see also text p. 73-74).
Parameters to be calculated:
Discharge
- given cross-section and stream velocity
measurements described above
- At 3 or 4 places along the stream, we will install a tag line (either
a distance-marked string or chalk-mark on the concrete) approximately
perpendicular to the stream. In your notes, identify these
stations using roman numerals, starting with I at the
upstream-most line.
- Each group will use yardsticks or rulers provided by the TA to measure
the vertical distance from the tagline to the water surface, and to the stream bed
at suitable intervals along the line. These intervals must be
spaced closely enough to allow accurate determination of the
stream cross-section (see Figs. 3.2-3.3).
- A second line will be installed an appropriate distance
downstream from the tag line, to allow velocity determination by
the float method
- Each group will measure the surface velocity at several points
along the tag line, and determine an average surface velocity
(Figs. 3.7-3.8).
- If there is sufficient water depth, each group will also
utilize the impeller flowmeter to determine the
variation of velocity with depth, and to compare to their
float-method velocity values. The flowmeter can be used to
measure an average velocity across small stream cross-sections
- If low water conditions are present, use the blue tub to
measure the discharge from the stream. Time how many seconds it
takes to fill the tub to the indentation mid-way up the side
(which is the 15 liter volume mark). Divide the volume by the
time to get the discharge.
- Calculate your discharge values and report them to
the other groups (preferably via WebCT) within one week after the
lab.
Suggested form for recording stream cross section data:
Stream Cross Section Measurements |
Name: |
Date: |
Team Members: |
Location: |
Tag line endpoints (lat, long, elev): |
Point Number |
Horizontal Position |
Distance to Water Surface |
Distance to Stream Bottom |
Notes |
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Suggested form for recording stream velocity data, float method
(after p. 63, Sanders, 1998)):
Stream Velocity Measurements (float method) |
Name: |
|
Date: |
Team Members: |
Location: |
Stream Section Number |
Section Width |
Downstream Distance |
Trial Number |
Time |
Surface Velocity |
Average Surface Velocity in Section |
Notes |
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See page 67, Sanders (1998) for a suggested form for
recording stream velocity data, velocity meter method.
In your lab writeup, please pay attention to the grading criteria
(section 1.2). In your discussion, you may want to
consider the following factors that can affect stream discharge
(after p. 50 Sanders, 1998):
- General topographic setting
- Site-specific topography and relief (a sketch or profile may
be helpful.
- Character of the floodplain and floodplain development.
- Description of the stream banks and bed.
- Sediment and rock exposed in cuts and in the stream bed.
- Soils on the bank and washover deposits.
- Vegetation: plant species, density and condition
- Evidence of animal activity in the stream
- Field observation of moisture content of the floodplain soils.
- Depositional features
- Erosional features
- Human development
- Evidence of flooding events
- Bank stability
For those who missed the field portion of this lab, do the following.
- set up a lab notebook
- begin with table of contents (i.e. one entry, plus a few
blank pages). Notebook should produce carbon copies, or be
prepared to photocopy each lab report to turn in for grading.
- start a lab report for Stream Gauging (title, date, purpose
sections)
- write a procedures section. This will be difficult, since
you weren't at the field lab. See the Stream Gauging
Parameters for a description of the measurements made. For
detailed explanation of procedures, use the textbook Chap. 3; or
the USGS National Handbook of Recommended Methods for Water-Data
Acquisition, UTD Library call # I 19.15/3:W4S/2/Chap1-4, pages
1-20 to 1-29.
- Reference the Class Results, pretend you were a member of one of the
three groups (A-C) and analyze their data for you Discussion
section. Compare your adopted group's results to the other
group's results for the remainder of your Discussion.
- Turn you lab notebook copies in at the beginning of the next lab
Next: Lab2 T.A.'s Notes
Up: Streamflow/Stream Gauging (Lab 2)
Previous: Lab2 Background
GEOS 3110 Professor's Notes, Summer 2007
Dr. T. Brikowski, U. Texas-Dallas. All rights reserved.