ENVS1017/ENVS6202 Assignment Scientific Report

ENVS1017/ENVS6202 Assignment 1 – Scientific Report Template
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Introduction (approx. 200 words)
 Short literature review on the topic, using an appropriate referencing style.
 You will need to define terms such as urban hydrology. Answer assignment Question 1 as
part of the introduction.
 State the aims of the assignment.
Write your text here:
Stream flow characteristics are impacted by human activities and is a reflections of soil and
vegetataion types, human use, weather and climate consitions, and land characteristics. Human
activities such as increasing development and construction of roads, buildings, parking spaces
inevitably alter the timing and strength of runoff events consequencing “flashy” systems (Birch,
Lean, and Gunns, 2015).. This variation impacts the biotic diversity within the stream ecosysem by
influencing essential habitat consitions. During a storm, a portion of the rainfall evaporates while
some infiltrate into the ground (Rutherfurd, Jerie, and Marsh, 2000).. The rest flows as a thin layer
of flows over land surface otherwise termed as overland flow. For a critically impervios stratum, the
the infiltrated water moves laterally in the soil surface joining the stream flow. This flow is termed
as interflow or underflow or sub-surface flow (Chin, O’Dowd, and Gregory, 2013). This has a
bearing on flow rate and velocity of stream at given conditions. This generally defines flow
Methods (approx. 200 words)
 This has been completed for you. You do not need to write or add anything to this section.
 Methods sections set out how the experiments and research were conducted.
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In the field we surveyed a channel cross-section perpendicular to the channel. Slope was
surveyed longitudinally along the top of the bank. We used an automatic level and staff for
these surveys. Levels were recorded to millimetre accuracy and our calculations checked
in the field. Slope was originally calculated using the rise over run method.
In the laboratory we calculated bankfull discharge for a range of different Manning’s n
roughness coefficients ranging from 0.009 to 0.2. These Manning’s n coefficients were
provided for us, but were originally derived using the component method.
We used the discharge equation as follows:
Q = V x A, where
Q = discharge (m 3
/s)
V = velocity (m/s)
A = cross-sectional area (m 2 )
Bankfull flow velocity was calculated using the following equation:
V = [(D 2/3
) x (S 1/2 ) ÷ n], where
V = mean channel velocity (m/s)
D = flow depth (m)
S = water surface slope (m/m; often approximated by the slope of the bed)
n = Manning's roughness coefficient
Cross-sectional area (A), bankfull channel depth and bankfull channel width were all
calculated from our processed cross-section.
Results (approx. 250 words)
 This is where you transfer the answers to the calculations you completed in the section
‘Assignment data to use’ of the assignment instructions onto Figure 1, and into Tables 1
and 2.
 Answer assignment Question 2 in the text box. You need to describe, in the text box, the
values you have calculated and any trends you see in the data. You need to cite your tables
and figures when describing the results.
 If you wish supplement your results with additional figures or graphs, you can. An
additional box for these is provided. The good use of figures in the results sections of
scientific reports is often critical. Be imaginative! If you choose to include additional
figures or graphs make sure you add figure numbers and titles to them. However, you
should never put a figure or table into a report and then provide no description of what
they show in the text.
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7.5
8.0
8.5
9.0
9.5
10.0
10.5
0 10 20 30 40 50 60 70
Height (m)
Distance (m)
Figure1Cross section acrossurban streamat MacquarieUniversity
floodplainchannelfloodplain
Figure 1 Cross-section across an urban stream in a coastal catchment near Sydney.
Table 1 Hydrology of an urban stream in a coastal catchment near Sydney.
Channel slope (m/m) 0.006
Bankfull channel depth (m) 2.1
Bankfull channel width (m) 25
Bankfull channel cross-sectional area (m2) 49.3
Table 2 Roughness scenarios, flow velocity and discharge characteristics of an urban
stream in a coastal catchment near Sydney.
Manning's n roughness for scenario 1 (smooth stormwater pipe) 0.009
Manning's n roughness for scenario 2 (moderate in-channel
vegetation)
0.05
Manning's n roughness for scenario 3 (woody debris and dense in-
channel vegetation)
0.2
Bankfull flow velocity for scenario 1 74.68
Bankfull flow velocity for scenario 2 13.44
Bankfull flow velocity for scenario 3 3.36
Bankfull discharge for scenario 1 3681.72
Bankfull discharge for scenario 2 662.59
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