Tóm tắt ta nghiên cứu xây dựng các giải pháp tổng hợp nâng cao hiệu quả công tác quản lý thoát nước tại thành phố cần thơ

Tóm tắt ta nghiên cứu xây dựng các giải pháp tổng hợp nâng cao hiệu quả công tác quản lý thoát nước tại thành phố cần thơ Tóm tắt ta nghiên cứu xây dựng các giải pháp tổng hợp nâng cao hiệu quả công tác quản lý thoát nước tại thành phố cần thơ Tóm tắt ta nghiên cứu xây dựng các giải pháp tổng hợp nâng cao hiệu quả công tác quản lý thoát nước tại thành phố cần thơ Tóm tắt ta nghiên cứu xây dựng các giải pháp tổng hợp nâng cao hiệu quả công tác quản lý thoát nước tại thành phố cần thơ Tóm tắt ta nghiên cứu xây dựng các giải pháp tổng hợp nâng cao hiệu quả công tác quản lý thoát nước tại thành phố cần thơ Tóm tắt ta nghiên cứu xây dựng các giải pháp tổng hợp nâng cao hiệu quả công tác quản lý thoát nước tại thành phố cần thơ

MINISTRY OF EDUCATION AND TRAINING

CAN THO UNIVERSITY

-o0o -

SUMMARY OF DOCTORAL DISSERTATION Major: Land and Water Environment

Code: 9440303

NGUYEN THANH NGAN

RESEARCHING FOR BUILDING INTEGRATED SOLUTIONS TO IMPROVE THE EFFICIENCY OF DRAINAGE MANAGEMENT IN CAN THO CITY

Can Tho, 2024

THIS STUDY WAS ACHIEVED AT CAN THO

UNIVERSITY

Supervisor: Assoc Prof Dr Nguyen Hieu Trung

The dissertation is defended under the School-level Doctoral Dissertation Assessment Committee

Meeting at: …

Time and Date: …

Reviewer 1: …

Reviewer 2: …

The dissertation is available at:

Learning Resource Center of Can Tho University

National Library Vietnam

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LIST OF PUBLICATIONS

1 Nguyen Thanh Ngan, Nguyen Hieu Trung (2021) Application of

Kriging Interpolation Method on Building Digital Elevation Model for Ninh Kieu and Cai Rang Districts of Can Tho City Proceedings International Conference on GeoInformatics for Spatial-Infrastructure Development in Earth and Allied Sciences GIS-IDEAS 2021, Naresuan University, ISBN: 978-4-901668-37-8, pp 219-226

2 Nguyen Thanh Ngan, Nguyen Hieu Trung (2021) Application of GIS

for Building the Geographic Database for Ninh Kieu and Cai Rang Districts of Can Tho City Proceedings International Conference on GeoInformatics for Spatial-Infrastructure Development in Earth and Allied Sciences GIS-IDEAS 2021, Naresuan University, ISBN: 978-4-901668-37-

8, pp 364-369

3 Nguyen Thanh Ngan, Nguyen Hieu Trung (2021) Applying Google

Earth Engine to assess the impact of urban flooding in Ninh Kieu district in the period from 2018 to 2021 42nd Asian Conference on Remote Sensing (ACRS 2021), Curran Associates, Inc., ISBN: 978-1-7138-4381-8, pp 835-842

4 Nguyen Thanh Ngan, Dinh Diep Anh Tuan, Nguyen Hieu Trung

(2022) Application of GIS on building the spatial database for supporting drainage management in Ninh Kieu District IOP Conference Series: Earth and Environmental Science, IOP Publishing, Online ISSN: 1755-1315,

964, 012002, doi:10.1088/1755-1315/964/1/012002

5 Nguyen Thanh Ngan, Nguyen Hieu Trung (2023) Application of GIS

and SWMM model to assess urban flooding in Metro Residential Area of Ninh Kieu District IOP Conference Series: Earth and Environmental Science, IOP Publishing, Online ISSN: 1755-1315, 1170, 012007, doi:10.1088/1755-1315/1170/1/012007

6 Nguyễn Thanh Ngân, Nguyễn Hiếu Trung (2022) Tổng quan về hệ

thống thoát nước đô thị bền vững SUDS Tạp chí Khí tượng Thủy văn

2022, EME4, Tổng cục Khí tượng Thủy văn, in tại Công ty TNHH Đầu Tư Nông Nghiệp Việt Nam, ISSN Print: 2525-2208, pp 158-168, doi:10.36335/VNJHM.2022(EME4).158-168

Chapter 1 INTRODUCE

1.1 Rationale of the research

Can Tho City is one of the important economic, political, scientific, educational, social and cultural centers of South Vietnam According to Decision 889/QD-TTg issued in 2009, Can Tho City is recognized as a grade I urban center directly under the Central Government, the largest city in the Mekong Delta region (Prime Minister, 2009; General Statistics Office, 2022) In terms of natural area, Can Tho City has an area of 1,440.4 km2, accounting for 3.52%

of the area of the whole region (40,921.7 km2), which is the smallest administrative unit in the Mekong Delta (General Statistics Office, 2022) In terms of population, the city has an average population of 1,247,000 with 619,100 men and 627,900 women (General Statistics Office, 2022) Population Can Tho City accounts for 7.16% of the whole region's population with 17,422,600 people (General Statistics Office, 2022) As of December 2021, the whole city has a population density of 866 people/km2, making it one of the administrative units with the highest population density in the Mekong Delta (General Statistics Office, 2022) Can Tho city is considered as a typical

“dynamic city” of the Southern Region, the city's development will play a role in the development of the whole Mekong Delta region (World Bank, 2014)

In the current period, along with economic growth, the phenomenon of urbanization in Can Tho City is also taking place at a fast pace and with a complicated direction This has caused great difficulties and challenges for urban managers in this area Besides urbanization, Can Tho City also faces a number of specific environmental problems such as climate change, urban flooding, sea level rise and land subsidence (World Bank, 2014) The combination

of these environmental problems creates a great pressure on drainage management activities in the city The traditional method currently used in drainage management in Can Tho City cannot meet the current demand for many subjective and objective reasons To solve these problems, city managers have applied many new technologies to drainage management The city has built a digital map system for the management of infrastructure of water supply and drainage systems as

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Nguyen Hieu Trung et al., 2012; Nguyen Hieu Trung et al., 2014) Besides, the city has also operated WebGIS to support environmental and water resource management (Ky Quang Vinh, 2010; Nguyen Hieu Trung et al., 2011, Truong Chi Quang et al., 2013; Le Van Thanh et al., 2014) as well as applying modeling tools to drainage management activities (Nguyen Thanh Loc, 2016; Nguyen Ngoc Toan, Nguyen Dinh Giang Nam, Nguyen Vo Chau Ngan, 2021)

The city government plans to renovate and build a new drainage system on 32 roads and two pumping stations in Ninh Kieu District (Tien Phong Electronic Newspaper, 2022) In addition, Can Tho City also proposes to use cameras, maps, drones, establish a network of collaborators to warn of floods, develop a planning plan that needs to take into account the topographical background (Tien Phong Electronic Newspaper, 2022) Sponsored by the World Bank and SECO, the ODA Project Management Unit in collaboration with city departments and agencies has implemented the project “Development of Can Tho City and Strengthening Urban Adaptability” (also known as Project 3) with three main components, in which Component 3 has the content

“Building a flood risk management information system for Can Tho City” named FRMIS (Can Tho City Portal, 2022) FRMIS is a support tool to help manage flood risks intelligently, automatically adjusting water levels, based on spatial data, water level data, hydrometeorological data, automatic control tools and equipments The system consists of two main parts, the FRMIS Operation Center and the SCADA system, which includes water level gauges, water quality probes, hydrometeorological probes, street cameras, data transmission system and the control system for the operation of culverts and pumping stations operates continuously all year round In addition, Project 3 also built a shared database component that has standardized

25 data layers of 3 sectors of Resources and Environment, Construction, Labor Invalids and Social Affairs (Traffic Electronic Newspaper, 2022) These projects show great efforts of scientists and managers in Can Tho City in renewing and improving management efficiency However, these projects have not been able to solve the existing problems with urban drainage management and flood reduction in Can Tho City

Ninh Kieu and Cai Rang are the modern economic, social, political, cultural and tourist centers of Can Tho City These are two of the nine district-level administrative units of the city, established under

Decree No 05/2004/ND-CP dated 02/01/2004 of the Government (Government, 2004) In the eyes of urban managers, these two central districts are considered as the development nucleus of Can Tho City, playing a role in promoting the overall development of the whole city Similar to the general characteristics of Can Tho City, the urbanization process in Ninh Kieu and Cai Rang takes place at a fast and strong speed This has made the drainage system no longer able to meet the current needs of the residential community, which has resulted in urban flooding becoming more and more serious over time This phenomenon has increased pressure as well as created great difficulties and challenges for drainage management in Ninh Kieu and Cai Rang

In order to have a basis for building practical, effective and synchronous solutions to this situation, the problem is to determine the current status of drainage management, urban flooding and flooded water quality in the two urban districts, where the drainage system is rapidly deteriorating and urban flooding is complicated

Because of the above reason, this research is carried out with the goal of building integrated solutions to improve the efficiency of drainage management and reduce urban flooding under the impact of uncertain factors on natural conditions and rapid socio-economic development like Can Tho City These solutions will help managers solve many outstanding problems, improve the efficiency of drainage management and reduce urban flooding in the study area The scope of the research focus mainly on solutions to manage drainage system and reduce urban flooding in the inner districts of Can Tho City because this is a very urgent problem that the city needs to solve immediately The results of the project will be the basis for improving people's quality of life and socio-economic development in Can Tho City

1.2 Research objectives

1.2.1 Overall objectives

Researching for building integrated solutions to improve the efficiency of drainage management and reduce urban flooding under the impact of uncertain factors on natural conditions and rapid socio-economic development like Can Tho City

1.2.2 Specific objectives

- Assessing the current status of drainage management, urban flood reduction and flooded water quality in the study area

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- Determining the impacts of changes in natural and socio-economic conditions on drainage management and urban flood reduction in the study area

- Proposing groups of integrated solutions to improve the efficiency of drainage management and reduce urban flooding in Can Tho City

1.3 Research contents

- Content 1: results of assessment of the current status of drainage management, urban flood reduction and flooded water quality in the study area

- Content 2: types of impacts and magnitude of changes in natural and socio-economic conditions on drainage management and urban flood reduction in the study area

- Content 3: integrated solutions to improve the efficiency of drainage management and reduce urban flooding in the study area

1.4 Scientific and practical significance

1.4.1 Scientific significance

In scientific terms, the research has systematized theoretical and practical issues related to drainage management and urban flood reduction in conditions of high natural variability and urbanization like Can Tho City The research is the methodological basis, orientation and reference for further studies on urban drainage management and flood reduction that will be implemented in Can Tho City as well as in the Mekong Delta in the future The research has evaluated the applicability of the SWMM drainage model in the simulation of urban drainage and flooding Besides, the research will also be a useful scientific basis for building solutions to improve the efficiency of drainage management and reduce urban flooding in areas of similar nature

1.4.2 Practical significance

In practical terms, the research has collected and built a comprehensive dataset on drainage management and urban flood reduction in Can Tho City This is a useful reference data source for future studies in the field of water supply and drainage as well as environmental science in the study area in particular and Can Tho City

in general The developed drainage scenarios and the forecast results of urban flooding are a reference source for assessing the impact of urban flooding on the population in the study area, this is a source of useful information for urban managers in Can Tho City With reliable input data sources, combined with appropriate research methods, the

integrated solutions built from this research will be the basis for solving the remaining problems, improving the efficiency of drainage management and reducing urban flooding, thereby reducing the impacts of flooding, contributing to stabilizing people's living conditions and ensuring stable economic development in the Can Tho City

1.5 New point of the thesis

- The research proposed a scientific and integrated approach to urban flood management, including calculating flood dynamics (mathematical model), analyzing the impact of drainage infrastructure management, assessing the impact of urban communities on drainage capacity and flooded water quality under the impact of uncertain factors such as changes in the Mekong River flood regime, rainfall regime due to climate change and local socio-economic development activities

- The research analyzed the feasibility and effectiveness of new solutions in reducing urban flooding according to the Green Infrastructure approach in scenarios of changes in flow and rainfall in the future under impact of climate change Through integrating this Green Infrastructure solution into mathematical models and Geographic Information Systems to quantitatively analyze the spatial distribution and flooding time of the study area Thereby quantifying the effectiveness of the solution, creating a scientific foundation for making flood management decisions as well as planning and designing urban residential areas in the Mekong Delta

Chapter 2 SUBJECTS AND METHODOLOGY

2.1 Research subjects and scope

- Applicability of the "Green Infrastructure" solution in drainage management and urban flooding reduction in Can Tho City

2.1.2 Research scope

- Spatial scope: the study area of the research is Can Tho city, the geographical location of this city is located in the center of the Mekong Delta region (Can Tho Department of Natural Resources and Environment, 2019):

+ The north borders Dong Thap province

+ The northwest borders An Giang province

+ The east borders Vinh Long province

+ The south borders Hau Giang province

+ The southwest borders Kien Giang province

The research topic focuses mainly on two urban districts of Can Tho City, including Ninh Kieu District and Cai Rang District In each

of the above districts, the author chooses a typical residential area frequently affected by urban flooding to simulate this phenomenon by SWMM drainage model and propose appropriate management solutions The selected areas are Metro Residential Area in Ninh Kieu district and Hung Phu 1 Residential Area in Cai Rang District

- Scope of time: the research period is expected to be from 2019 to

+ Researching theoretical foundations of drainage management and urban flood reduction in Can Tho City

+ Researching legal bases, legal documents, policies on drainage management and urban flood reduction in Can Tho City

+ Researching practical basis of drainage management and urban flood reduction in Can Tho City

- From the research of the above issues, it will systematize the scientific, legal and practical bases on drainage management and urban flood reduction in the study area This is an important step to orient and define the objectives, contents, scope of research as well as methods and processes to carry out the research

- Consulting with supervisors, experts and colleagues to assess whether the research orientation is consistent with the actual requirements at the study area

- Conducting field surveys at the study area to update detailed and factual information for the research process:

+ Collecting data and documents on: (1) natural and socio-economic conditions in the study area, (2) hydro-meteorological characteristics in the study area, (3) the current status of the drainage system, (4) current status of drainage management, (5) urban flooding

+ Taking pictures and preliminary assessment of the current status of the drainage system by actual observation Surveyed objects include sewer lines, water collection manholes, receiving sources, rivers and canals

+ Taking photos and preliminary assessment of urban flooding by actual observation Surveyed objects include flooded locations, inundation depth, inundation time, and damage caused by flooding

- Collecting digital maps, CAD drawings, satellite images for research including: (1) administrative boundaries, (2) transportation systems, (3) waterways systems, (4) topographical surfaces, (5) land use features, (6) drainage systems, (7) urban flooding, (8) satellite images with different spatial resolutions

- Using GIS software to reprocess digital maps, CAD drawings with the same structure, format and coordinate system to be able to overlay and analyze data

- Using statistical software to perform descriptive statistics about the parameters of the drainage system and the current flood situation in the study area

- Carrying out survey by survey form for households living in two residential areas Metro and Hung Phu 1 The number of subjects to conduct the survey is determined based on Slovin's formula (published

in 1960) Slovin's formula looks like this:

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In there:

- n: the minimum sample size required

- N: the overall size

- ε: the allowed error (%)

The content of the survey includes 18 questions related to the research content

+ Metro Residential Area: 86 survey votes

+ Hung Phu 1 Residential Area: 90 survey votes

- Using statistical software to synthesize and process interview results with survey questionnaires

- Planning for sampling and analysis of flooded water quality at frequently flooded locations in the study area The number of selected indicators of flood water quality analysis is seven:

+ pH: analyzed according to TCVN 6492:2011

+ DO: analyzed according to TCVN 7325:2016

+ BOD5: analyzed according to TCVN 6001-1:2008

+ COD: analyzed according to SMEWW 5220C:2017

+ Total N: analyzed according to TCVN 6638:2000

+ Total P: analyzed according to SMEWW 4500-P.B&E:2017

+ Coliform: analyzed according to SMEWW 9221B:2017

- Using statistical software to synthesize and process flood water quality analysis results, build graphs showing the results

- Using GIS software to digitize and build data layers on the current status of urban drainage system and flooding on digital maps

- Using GIS software to determine the boundaries of drainage basins and main drainage directions in the study area

- Using GIS software to interpolate to create DEM from topographic data at the study area

- Using GIS software to build spatial database on drainage management for the study area

- Using the Sentinel-1 satellite image interpretation tool on the Google Earth Engine platform to determine the flooded area over the years in the study area

- Researching, evaluating and selecting a suitable drainage model to simulate the main parameters of the drainage system and the flooding phenomenon in two residential areas Metro and Hung Phu 1

- Calibrating model parameters by actual measurement results and advice from experts

- Using the selected drainage model to simulate the main parameters of the drainage system and urban flooding for the current scenario in two residential areas Metro and Hung Phu 1

- Consulting with supervisors, experts and colleagues to evaluate the results obtained from the simulation process with the drainage modeling software selected for the current scenario

- Assessing the current status of drainage system and flooding in two residential areas Metro and Hung Phu 1

- Presenting research results at conferences, seminars, scientific papers and synthesizing opinions and comments of experts and managers to have a basis for assessing whether the results are consistent with reality

or not

2.2.2 Content 2

- Collecting data and documents on: (1) socio-economic development, (2) land use planning information, (3) drainage planning information, (4) policy system of the State for the management of urban drainage and flood reduction, (5) the impact of climate change on the research area

- Inheriting research results on climate change and sea level rise to serve as a basis for determining impacts as well as as input data for building simulation scenarios using drainage modeling software

- Using statistical software to synthesize and process results of climate change and sea level rise scenarios for the study area along with various types of land use and drainage planning information as input data for the drainage modeling software

- Using GIS software to perform the following tasks:

+ Digitizing data layers showing changes in natural and economic conditions in the study area

socio-+ Digitizing and processing data layers showing information on land use planning and drainage planning in the study area

- Using selected drainage modeling software to simulate key parameters of urban drainage and urban flooding for future scenarios in two selected residential areas

- Consulting with supervisors, drainage experts, colleagues, managers

at the study area to evaluate the results obtained from the simulation process with selected drainage modeling software for future scenarios

+ Using GIS software to present simulation results from models in the form of maps

- Organizing conferences and seminars to present the results and synthesize comments from experts in many related fields and local managers to have a basis for assessing whether the results are consistent with reality or not

- Identifying locations where green infrastructure solutions can be deployed in the study area based on maps and drainage planning

- Developing appropriate solutions based on green infrastructure for locations that can be deployed in the study area Using GIS software to represent these solutions on digital map data layers to present the results

- Using selected drainage modeling software to simulate the main parameters of the drainage system in two selected residential areas in the case of application of green infrastructure solutions to evaluate the effectiveness of the drainage system

Chapter 3 RESULTS AND DISCUSSION

3.1 Current status of urban flood and drainage management in the study area

3.1.1 Survey results on the current status of drainage system in Metro and Hung Phu 1 Residential Area

According to the survey results, 100% of people in two residential areas Metro and Hung Phu 1 answered that their area has a drainage

system Through the interview process, the surveyed subjects also demonstrated their understanding of the layout of drainage system components in these areas Most of the surveyed subjects assessed that the drainage system in two residential areas was operating normally (Metro residential area 91.86%, Hung Phu 1 residential area 93.33%)

In addition, there are also a small number of surveyed subjects evaluating that the drainage system in two residential areas is in good working order (Metro residential area 5.81%, Hung Phu 1 residential area 6.67%) Particularly in Metro Residential Area, two surveyed subjects rated the drainage system not working well (2.33% of the survey votes) Residents in Metro Residential Area said that this area operates food services and hotels, so sometimes the smell from the sewers affects their lives and work In addition, people in this area also said that when there is heavy rain, rainwater mixes with sewage and sludge in the sewers to form a black, foul-smelling and viscous mixture

- Sanitary wastewater is pre-treated by a septic tank before being discharged into the manifold

- The process of wastewater drainage can be deposited at manholes, which can take advantage of tidal water to wash and dissolve wastewater

- Rainwater contributes to washing and cleaning the drain

- The manifold is built with bricks in the form of an open ditch covered with a reinforced concrete knit cap

- The common drainage system uses circular sewer pipes made of centrifugal reinforced concrete

The design and material characteristics of the drainage system are one of the main reasons why the sewers are prone to clogging due to