Civil Engineering Project: Hydrological Analysis of Catchment Areas

This project focuses on evaluating variations in catchment response behavior in pre-developed and post-developed settings within a specific region. It involves estimating physical parameters, constructing rainfall hyetographs, and generating storm hydrographs. The methodology includes detailed steps for rainfall analysis, excess hyetograph construction, desired duration unit hydrograph construction, and network diagram creation. The student engineer must apply critical thinking and engineering judgments to address potential challenges and create a functional design. The project utilizes learning models and computational simulations, including verification using HEC-HMS, to analyze the floodplain of the catchment areas. The analysis covers various aspects of hydrology, including rainfall, runoff, and the impact of urban development, with the aim of providing solutions to mitigate potential risks and improve water management. The project also involves obtaining and processing temporal rainfall data from the ARR website and applying relevant formulas for accurate hydrological analysis. The student must consider the effect of various parameters such as area, length, and time, for complete project analysis.

Contents
SCOPE........................................................................................................................................................2
INTRODUCTION.......................................................................................................................................3
STEP 1: PHYSICAL PARAMETERS ESTIMATION...............................................................................5
METHODLOGY
STEP 2: RAINFALL HYETOGRAPH CONSTRUCTION........................................................................9
STEP 4: DESIRED DURATION UNIT HYETOGRAPH CONSTRUCTION.........................................18
STEP 5: STORM HYETOGRAPH COMPUTATION..............................................................................24
STEP 6: NETWORK DIAGRAM CONSTRUCTION..............................................................................28
STEP 7: CONSTRUCTION OF POST DEVELOPMENT HYDROGRAPH...........................................34
STEP 8: VARIFICATION BY HEC HMS................................................................................................42
CONCLUSION.........................................................................................................................................52

SCOPE
This research aims to evaluate and evaluate variations in catchment response behavior in pre-
developed and post-developed settings within a specific region and to propose solutions that can
address possible difficulties along the route.
The physical parameters for the clock and the generation of the respective rainfall patterns and
storm hydrographs will include an evaluation of different parameters and the application of
various techniques to fulfil the tasks indicated in the project brief to achieve the correct definitive
results for the clock assigned.
In order to overcome problems and create a functional and safe design in compliance with the
directives of the Council, critical thinking, analytical skills and Engineering judgments will have
to be implemented at various stages of the project design and analysis by the student engineer.
The project gives the student engineer the capacity to examine and plan the floodplain of the
catchment areas during the pre-development and post-development process. Furthermore, the
student engineer could offer a response to challenges that could develop at any time in the
project.
For the development of the project, several learning models and computational simulation should
be employed and a real-life problem that needs to be solved should be associated and worked on.
INTRODUCTION
Hydrology is important to civil and environmental engineers, hydro geologists, and earth
scientists, and it plays an important part in water management, droughts, and floods, as well as
the techniques for dealing with them. Issues relating to urban storm water and runoff, water

safety, and watershed conservation have prompted comprehensive and in-depth studies and
measures to be implemented in order to protect water balance and support productive production
while minimizing potential risks. Multiple storm events (such as hurricanes, cyclones, torrential
rains, and so on) have triggered major urban disasters in recent years, particularly in coastal areas
where economic growth has been rapid, and potential responses to these problematic events
(Bedient, Huber, and Vieux) must be investigated and addressed.
The total amount of precipitation (also known as rainfall) remains in the area where it fell and
contributes to the atmosphere through evaporation and transpiration (water vapors leaking
through plant tissue and leaves). Evapotranspiration is the term used to describe these two
mechanisms. Any water that reaches the surface causes infiltration. The permeability of the soil
and its ability to absorb and hold water have an impact on this mechanism. Percolation, the
process of replenishing groundwater sources, can begin after this stage. Pumping groundwater
for farm and urban water sources is possible (U.S. Geological Survey Agency, 2017).
When the surface is totally saturated or the surface has weak permeability properties, the
remainder of the precipitation goes overland or run-off. Run-off travels in a downward direction,
accumulating in isolated, local water sources before migrating to the main. This is the larger
body of water. Excess run-off is a parameter that needs to be addressed as cities grow (Loaiciga,
Valdes, Vogel, Garvey & Schwarz, 1996).
It is feasible to define regions where improvements in topography and construction can have a
significant impact on flood behaviour by being able to identify and consider floodways, and so
take a critical step toward recognising flood activity and developing viable flood control
techniques (Albert, Murtagh, Babister, McLuckie, 2017).

By increasing nutrient retention within the channel network and improving downstream water
quality, as well as raising channel roughness, effective approaches can be achieved, such as
mitigating channel erosion (protecting soil and reducing sediment supplies to downstream water
bodies), increasing nutrient retention within the channel network and improving downstream
water quality, and finally, decreasing floods in the lower catchment area.
Finally, with today's improved data on radar precipitation and moisture gauges, advanced
processing capacity, and improved hydraulic simulation tools, simulations covering wide regions
using diverse approaches may be easily analysed. This provides a lot of benefits, but it also
causes some uncertainty. This is because precipitation is the most important factor in calculating
runoff, and the improved spatial clarity provided by radars, when combined with computer
simulation, can aid in better understanding the total catchment response, as long as these
apparatuses and instruments are properly configured for the simulation to be performed. If proper
calibration can be ensured, efficient and accurate hydrological analysis for floodplain control
programmes and planning strategies can be implemented (Daly, Reichard, Hansell & Clark,
2016).

1. PHYSICAL PARAMETERS ESTIMATION

1.1. Allocation of basin/watershed.
Basin A was given to the student engineer since the student's identification number fell within
the boundaries of that range. As student ID is 19309705 thus it comes under the category of
Basin A. The centroid of this basin is located at 150.58o East longitude and 33.53o South latitude.
The basin is depicted below.
Using Approximation 1000m
We can convert the said Catchment area as

1.1.1. Area of the Sub-Catchment
Sub-Catchment Area
1 3.96 Km2
2 5.87 Km2
3 3.01 Km2
Total 12.84 Km2

1.2. Estimation of Total area of Basin.
Area of Total Basin: Area of sub basin 1 + Area of sub basin 2 + Area of sub basin 3.
Area of Total Basin: 3.96 km2 + 5.87 km2 + 3.01 km2.
Area of Total Basin: 12.84 km2.
1.2.1. Total Area of the Catchment-A
128 Square Kilometer = 12.84 Square Kilometer as per Given Approximation
Similarly, Area calculated as 12.84 Km2
1.3. Estimation of Length of Channels.
1.3.1. Length of Channels
Length of Channel as
Channel A (Including 1 and 2 outlet)
Total Length = 9.86 Km

Channel B (Including 1 outlet only)
Total Length = 10.7 Km
Channel C (Including 1 outlet only)
Total Length = 9.56 Km

METHODOLOGY
2. RAINFALL HYETOGRAPH CONSTRUCTION
RAINFALL HYETOGRAPH CONSTRUCTION.
From Bureau of Meteorology web site (http://www.bom.gov.au) IDF table and graph are shown
below.
2.1. IFD Design Rainfall Depth (mm)