Surface Water Hydrology Project Autumn 2021: Catchment B Analysis

This Surface Water Hydrology Project, conducted in Autumn 2021, focuses on the analysis of Catchment B near Macquarie Field. The project begins with the allocation and physical parameter estimation of the basin, calculating the area and channel lengths. It then delves into rainfall intensity and depth calculations using IDF curves and AEP. The core of the project involves the application of the Unit Hydrograph method to predict flood hydrographs, supported by detailed calculations and Excel sheets. The Muskingum routing method is utilized to analyze flow, with step-by-step calculations of routing parameters and discharge. Furthermore, the project includes HEC-HMS files to verify calculations and present the storm hydrograph. The project concludes with results, conclusions, and recommendations, emphasizing the importance of advanced learning models and computational simulations for future improvements. The project provides a comprehensive analysis of the catchment, incorporating various hydrological methods and tools.

Surface Water Hydrology
Project
Autumn 2021

INTRODUCTION
PHYSICAL PARAMETERS ESTIMATION.
Allocation of basin/watershed.
The Catchment assigned to me according to my Roll No. was Catchment B, this Catchment B is
situated near Macquarie Field, Picnic Point area has a centroid situated at 33 o 358’ S latitude and
150 o 35’ E longitude.
Using Approximation 1000m
We can convert the said Catchment area as

1 - Area of the Sub-Catchment
Sub-Catchment Area
1 2.89 Km2
2 5.85 Km2
3 3.36 Km2
Total 12.1 KM2
2 – Total Area of the Catchment-B

121 Square Kilometer = 12.1 Square Kilometer as per Given Approximation
Similarly, Area calculated as 12.1 Km2
3 – Length of Channels
Length of Channel as
Channel A (Including 1 and 2 outlet)
Total Length = 9.83 Km

Channel B (Including 1 outlet only)
Total Length = 10.7 Km
Channel C (Including 1 outlet only)
Total Length = 9.51 Km

Figure 1 rainfall depth IFD for basin 2

Figure 2 rainfall intensity IDF for basin 2

Figure 3 Rainfall depth (mm) chart

Figure 4 Rainfall intensity (mm/hr) chart

Relationship used here is
AEP = 1−e( −1
ARI )
AEP = 1−e(−1
10 )
= 1-0.90483 =0.095*100 = 9.5%

As per above data we can calculate the depth as
Considering duration of rain is 6 hours
Then
As per AEP = 10% Duration 6 hours the Depth will be
50.8 mm
(As Per Latest Method of Calculation)

UNIT HYDROGRAPH
• Very often it is required to predict the flood hydrograph resulting
from a known storm
• A large number of methods are available to solve this problem
• Unit Hydrograph Method is the most popular and widely used
method for predicting flood hydrograph resulting from a known storm
Definition : A unit hydrograph is defined as the hydrograph of direct
runoff resulting from one unit depth (1cm) of rainfall excess occurring
uniformly over the basin and at a uniform rate for a specified duration
(D hours)
FOR UNIT HYDROGRAPH AND STORM HYDROGRAPH, SEE THE EXCEL
SHET ATTACHED FOR DETAILED CALCULATIONS

Solution
Using Muskingum routing Method and Assuming x=0.2
And average channel velocity is 1.2m/sec
Time (Min) Discharge (m3/sec)
0 0
5 0.54
10 1.76
15 3.28
20 3.75
25 3.36
30 2.55
35 1.59
40 1.05
45 0.72
50 0.48
55 0.32
60 0.21
65 0.14
70 0.09
75 0.06
80 0.04
85 0.03
90 0.02
95 0.01
100 0

Calculation of basic parameters as
D = (K-Kx)*0.2+0.5Dt
D =(5-0.54)*0.2+0.5*3 = 4.89 + 1.5 = 6.39
Now Calculating C0
C0 = (0.5Dt-Kx)/D = (0.5*5-0.54*0.2)/6.39=0.07
Similarly, for C1
C1 = (0.54*0.2+0.5*5)/6.39=0.07=0.560
Similarly, for C2
C2 = (5-4.69*0.2-0.5*5)/6.39=0.07=0.38
Check if
C0 + C1 + C2 = 1
0.07 + 0.570 + 0.38 = 1.01 (Change the Largest Weight)
C1 = 0.55
Now using Routing equation
O2 = CoI2 + C1I1 + C2O1 = 0.07I2 + 0.55I1 + 0.38O2
Time (Min) Discharge (m3/sec) O (m3/sec)
0 0
5 0.54 0.46
10 1.76 1.50
15 3.28 2.79
20 3.75 3.19
25 3.36 2.86
30 2.55 2.45
35 1.59 1.88
40 1.05 1.28
45 0.72 0.98

0 10 20 30 40 50 60 70 80 90
0
1
2
3
4
5
6
0
0.948
2.1744
3.9588
4.806
4.0704
3.2904
2.3976
1.7736
1.2828
0.948 0.72480.50160.39 0.27840.22320.11160
Basin 'B'
0 5 10 15 20 25 30 35 40 45 50
0
0.5
1
1.5
2
2.5
3
3.5
4
Time (Min)
Discharge (m3/sec)
Also include Muskingum HEC-HMS Files
Basin B:

0
60
120
180
240
300
360
420
480
540
600
660
720
780
840
900
960
1020
1080
1140
1200
1260
1320
0.00
5.00
10.00
15.00
20.00
25.00
30.00
Basin B
Storm Hydrograph Moving average (Storm Hydrograph)
Figure 5 storm hydro graph basin 2 (pre development)

Check Calculations in Excel Sheet Attached
Basin A
Basin B
Outlet
Basin C

Check Calculations in Excel Sheet Attached
Attached HEC HMS Files shows and verified the desired
calculations and Results

Verification from HEC HMS Sofware

Results and Conclusion and
Future Recommendations
This basic task required the plan engineer to deal with a self-ruling explanation and
to think about the portion, measures and rules to be taken in the pre-and post-
improvement floodplain assessment of the catchment area. The idea incorporated a
watershed study containing three sub-gets and one channel with different
highlights and properties. Particular arranging choices and techniques and
references have been fundamental and applied to make ideal and positive/clear
results, while simultaneously having the decision to pass on a respectable result
that fulfills the depicted assignment necessities.
My Recommendations is to apply more extraordinary learning models and
computational reenactment, while at this point getting a chance to accomplice and
work on a certified issue that needs an authentic plan too.