(Tiểu luận) simulate the outflow of la nga river basin (or sub basin) by the hec hms model, find out the set of model parameters after calibration and validation, and analyze the results

HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY
FACULTY OF ENVIRONMENT AND NATURAL RESOURCES
DEPARTMENT OF ENVIRONMENTAL ENGINEERING

PROJECT WORK: Environmental Hydrology

Simulate the outflow of La Nga River basin (or
sub-basin) by the HEC-HMS model, find out the
set of model parameters after calibration and
validation, and analyze the results
Supervisor:

Assoc. Prof. Huynh Cong Hoai
Dr. Nguyen Thi Thuy Hang
EN2023
La Dang Khoa-1852472
CC001

Course code:
Group member:
Class:

Ho Chi Minh City, 1st October 2022

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Table of Content
Part I............................................................................................................................... 4
I

Introduction of La Nga river:..............................................................................4
1.1 Location of La Nga River – Phu Ngoc catchment............................................4
1.2 Input Data.........................................................................................................6

II. Catchment delineation............................................................................................7
2.1

The concept of catchment delineation..........................................................7

2.2

Catchment delineation method.....................................................................7

III Discussion on the results...................................................................................15

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Table of Figure
Figure 1 Location of La Nga river............................................................................... 4
Figure 2: Phu Ngoc catchment - Lam Dong, Binh Thuan, Dong Nai provinces (La
Nga River) (107.315 0E, 11.098 0N)....................................................................................... 5

Figure 3: Collecting information from earthdata.nasa.gov....................................... 7
Figure 4: Datas are inputed......................................................................................... 8
Figure 5: Result of using “Mosaic to new raster”...................................................... 9
Figure 6 Result of using "Fill" tool........................................................................... 10
Figure 7 Result of using "Flow Direction" tool........................................................ 11
Figure 8: Result of using "flow accumulation"........................................................ 12
Figure 9: Result of using “raster calculation” tool................................................... 13
Figure 10: Result of “watershed” tool....................................................................... 14
Figure 11: Result of calculating catchment area...................................................... 15

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Part I
I

Introduction of La Nga river:
La Nga is the name of a river which located at the southern of Vietnam and also a

tributary of Dong Nai River. La Nga river originates in Di Linh plateau flowing along Bao
Loc city of Lam Dong province, It flows through Lam Dong, Binh Thuan and Dong Nai
provinces for over 272 km and has a catchment area of 4,710 km² and finishes at Tri An
lake.

1.1 Location of La Nga River – Phu Ngoc catchment:

Figure 1 Location of La Nga river.

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Phu Ngoc is a commune of Dinh Quan District, Dong Nai Province, Vietnam.

Figure 2: Phu Ngoc catchment - Lam Dong, Binh Thuan, Dong Nai provinces (La
Nga River) (107.315 0E, 11.098 0N).

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1.2 Input Data:
From we can collect data with this code
“C1575726572-LPDAAC_ECS”, use rectangle tools scan the needed research area and then
download it.
The ASTER Global Digital Elevation Model (GDEM) Version 3 (ASTGTM) provides
a global digital elevation model (DEM) of land areas on Earth at a spatial resolution of 1 arc
second (approximately 30 meter horizontal posting at the equator).
The development of the ASTER GDEM data products is a collaborative effort between
National Aeronautics and Space Administration (NASA) and Japan’s Ministry of Economy,

Trade, and Industry (METI). The ASTER GDEM data products are created by the Sensor
Information Laboratory Corporation (SILC) in Tokyo.

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Figure 3: Collecting information from earthdata.nasa.gov.

II. Catchment delineation
2.1

The concept of catchment delineation

Catchment is the area contributing to the discharge at a particular river cross section.
The size of catchment increases if the point is selected as outlet moves to the downstream of
river.
Delineation is based entirely on topographic and river network information. The
catchment boundary to any required (usually gauged) point on the river network is defined
by applying GIS tools to an appropriate digital elevation model.

2.2

Catchment delineation method

a. Manual Delineation
– Hand-drawing watersheds on the map

b. Automatic Delineation (Digital Elevation Model DEM Based)
– Use Hydrology tool in ArcGIS. It is a geographic information system for working
with maps and geographic information maintained by the Environmental Systems Research
Institute.

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In this research, I use Arcmap10.5 to automatically preform catchment delineation
from the given “ by following these steps:
Step 1: Download DEM. This step has been described in “1.2 input data”.
Step 2: Combine multiple raster datasets.

Figure 4: Datas are inputed

To combine multiple raster datasets, using the “mosaic to new raster” tool from
“catalog” or we can search this tool by press “Ctrl + F”.

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Figure 5: Result of using “Mosaic to new raster”

Step 3: Fill DEM to remove gaps and errors.

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Figure 6 Result of using "Fill" tool.

Step 4: Calculate Flow Direction

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Figure 7 Result of using "Flow Direction" tool.

Step 5: Calculate Flow Accumulation

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Figure 8: Result of using "flow accumulation".

Step 6: Create Stream Network
Set ‘FlowAccumulation’ > 40,000

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Figure 9: Result of using “raster calculation” tool.

Step 7: Create watershed Pour points
Watersheds are defined by outlets (pour points)
• Pour points should be placed in high-flow pathways
• Basins will be generated from pour point to ridgeline or to upstream sub-basin
• Pour points should be numerically coded per sub-basin
• Pour points must be converted to a grid layer
Step 8: Create watershed boundary
After combining pour point and flow direction, we have watershed boundary.

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Figure 10: Result of “watershed” tool.

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Step 9: Calculate area of the catchment

Figure 11: Result of calculating catchment area.

2.3. The area of La Nga river – Phu Ngoc catchment.
According to figure 11, the area of Phu Ngoc catchment is 646.032774 km2.

III Discussion on the results
This article is a small research about the Phu Ngoc river catchment. It showed the way
how we apply GIS to delineate the catchment of Phu Ngoc. There were some problems
while program were running like program stop working, time-consuming in using fill tool,
some errors appear, etc. However, Arcmap 10.5 is automatic useful program that we can use
for catchment delineation, which is much easier than hand-writing. ArcGIS creates maps that
require categories organized as layers. Each layer is registered spatially so that when they’re
overlaid one on top of another, the program lines them up properly to create a complex data
map. The base layer is almost always a geographical map, pulled out of a range of sources
depending upon the visualization needed (satellite, road map, etc).

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