Luận văn Optimal reservoir operation for water supply in dry season: The case study of Cua Dat reservoir in the Ma – Chu river basin
MINISTRY OF AGRICULTURE AND RURAL DEVELOPMENT
WATER RESOURCES UNIVERSITY
**************
OPTIMAL RESERVOIR OPERATION FOR WATER SUPPLY
IN DRY SEASON: THE CASE STUDY OF CUA DAT
RESERVOIR IN THE MA-CHU RIVER BASIN
TRINH XUAN MANH
MSc Thesis
September 2014
Optimal reservoir operation for water supply in dry season: the
case study of Cua Dat reservoir in the Ma – Chu river basin
Master of science thesis
By
Trinh Xuan Manh
Supervisor
Dr. Nguyen Mai Dang (WRU)
Mentors
HA NOI
September 2014
This research is finished for the partial fulfillment of requirements for the Master of science
degree at Water Resources University, Ha Noi, Viet Nam
i
Abstract
Water supply of reservoirs and especially reservoirs used for irrigation,
hydropower, aquaculture, navigation, environment…in the dry season are often
troubled due to increasing water demands according to the economic development and
society, while the flow to the reservoir is limited. In recent years, the depletion of the
river flow during the dry season occurs more frequently and at a more intense level.
This is partly due to forest coverage reduction in the upstream of river basins, and
partly due to the effects of climate change.
Hence, computation of the optimum water supply of reservoir for the water
demands in the dry season is needed. This study presents the initial research on
applying Fuzzy Logic Algorithm for optimal operation of water supply in the dry
season of 2011-2012 of the Cua Dat Reservoir in the Chu River basin, Thanh Hoa
province. The Cua Dat Reservoir is a multi-purpose reservoir for the following tasks:
flood prevention, water supply, irrigation, power generation, and environmental flows.
In addition, MIKE 11 model is also used to simulate the release from the reservoir to
the downstream to evaluate the efficiency of the optimal method.
The research used Fuzzy Logic algorithm based on the rule, the principle of "IF
- THEN" and built the membership functions for the input variables: water level,
inflow to the reservoir, the water demands, and discharge from the reservoir. It is
developed for the Fuzzy operating systems for the Cua Dat Reservoir and is meant to
determine the optimal discharge process in case of shortage of water in the dry season.
Inflows, releases and water levels of the Cua Dat Reservoir were collected from actual
operation of the reservoir. For water demand of stakeholders, the author determined
that the total water demand for whole area was about 4547 Mi.m3. For hydropower
based energy production water is used at the largest rate (67% of total water demand),
while domestic purposes water is obtained smallest rate of water use of the Cua Dat
Reservoir.
Finally, the results from optimal method, the reservoir can meet 80% of water
demand more than actual release throughout the dry season of 2011-2012. The initial
research has been successful and the results showed that this method can be applied
well to the optimal reservoir operation in Vietnam.
Key words: Cua Dat, reservoir operation, optimization, Fuzzy Logic, water
demand, Fuzzy rule, MIKE 11 model.
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MSc Thesis
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Acknowledgement
First of all, I would like to give a big thank to all people who have supported
and assisted me during the Master Thesis Research. Thanks for their support,
encouragement and guidance that allowed me to complete this study in time.
Especially, I would like to express my appreciation to Dr. Nguyen Mai Dang,
my supervisor, for his unlimited encouragement, guidance, comments and technical
supports on the Fuzzy Logic approach and other models as well as the thesis writing
process from the beginning of the thesis research.
I would like to thank NICHE-VNM-106 project from the Government of the
Netherlands for their financial support during the MSc study in the ThuyLoi
University. I thank to Mrs. Hoang Nguyet Minh and Mrs. Vu Thi Thuy Ngan who
made a linkage between me and NICHE. I also would like to thank Assoc. Prof. Dr.
Nguyen Thu Hien, Dean of the Faculty of Water Resources Engineering, for her help
and comments during the Master study in the ThuyLoi University.
I wish to thank Dr. Ilyas Masih and Ms. Martine Rutten for their feedback,
references and support from the proposal process.
I also wish to thank Mrs. Mariette Van Tilburg, my English teacher, for her
comments and support from the final thesis report.
I also want to thank the ThuyLoi University (TLU), Song Chu Irrigation
Company, National center for Hydro-Meteorological Service (HMS) for providing me
very useful data sets.
Thanks to all of my colleagues at the HaNoi University of Natural Resources
and Environment in Vietnam for your assistance in the last two years. You will always
be in my mind.
Last but not least, I want to take this opportunity to show my appreciation to my
family, my close friends for their inspiration and support throughout my life; this
research is simply impossible without you.
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Table of Contents
I.2. Problem statement..................................................................................................2
I.3.1. Objectives of the study..................................................................................3
II.3. Overview of hydraulic and hydrological modeling..............................................9
III.1. Description of the study area.............................................................................13
IV.1.1. Meteorological data..................................................................................30
IV.1.3. Cua Dat reservoir operation data..............................................................34
IV.3.1. Determination of the model inputs...........................................................62
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List of Figures
Figure 3-2: Ma – Chu River Network in Viet Nam.......................................................16
Figure 3-5: The main dam of the Cua Dat Reservoir ....................................................28
Figure 3-6: The spillway of the Cua Dat Reservoir ......................................................28
Figure 3-7: The storage of the Cua Dat Reservoir ........................................................28
Figure 3-8: The intake tower of the Cua Dat Reservoir................................................28
Figure 3-9: The gate of spillway of the Cua Dat Reservoir ..........................................28
Figure 3-10: The Bai Thuong weir................................................................................28
Figure 4-6: Schematization of hydrological station network ........................................34
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Figure 4-31: Structure of fuzzy system for Cua Dat reservoir ......................................73
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List of Tables
Table 3-2: Characteristics of river shape of some large tributaries...............................15
Table 3-4: Annual rainfall characteristics......................................................................20
Table 4-1: Kinds of data have been used in the study...................................................29
reservoir..........................................................................................................................36
Table 4-3: Plant coefficients of paddy...........................................................................39
Table 4-4: Plant coefficients of other plants..................................................................39
Table 4-5: Water requirement of Spring paddy in 2011................................................40
Table 4-6: Water requirement of winter paddy in 2011 ................................................41
Table 4-7: Water requirement of sugar cane in 2011 ....................................................42
reservoir..........................................................................................................................45
Table 4-11: Structure of water use of whole area in 2011.............................................48
Table 4-13: List of tributary basin on the Ma – Chu river basin ...................................64
Table 4-16: The NASH for calculation of alternatives..................................................74
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CHAPTER I
INTRODUCTION
I.1. Background
Reservoirs play an important role in the development of many countries.
Nowadays, there are many reservoirs and dams which were built in many developing
countries for various purposes, for example, water supply, flood control, electric
generation, environment and recreation…However, in 18th Century reservoirs were
built to supply water, flood control and navigation as the main purposes, after that
reservoirs were built for hydropower generation purpose by increasing demand for
energy consumption of human.
As mentioned above, most of reservoirs are used for multiple-purpose. All
those purposes need to be satisfied but the capacity of reservoir is limited. For this
reason some conflicts may happen among the water users who have other interests and
conflicts also may happen in reservoir itself. For hydropower generation, higher
storage of water is needed, on the contrary, much water should be relaesed for
cultivated areas in dry season especially. Besides this, there are also many other
conflicts in user factors such as transportation and hydropower generation, flood
control and environment…etc.
Vietnam has many big river networks with nine major river basins spread along
the country. At present, many multi-purpose reservoirs were built to serve the socio-
economic issues such as Cua Dat, Hoa Binh and Dau Tieng Reservoir...etc. The
management and operation for many purposes are really difficult. On the other hand,
the operation of each reservoir is a challenge for management and operators. Reservoir
operation is needed to balance efficiently interests of water users and satisfy constraint
systems aim to get maximum interests. An optimal policy is necessary to accomplish
the problem objective and rule curve is one of appropriate methods to determine
operation policy of reservoir. Reservoir operation policy specifies the criteria to retain
or release water in or from a reservoir at different times of the year depending upon the
inflows and demands.
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Optimization model used the mathematical programming technique to find the
best possible solution based on a specific performance function and some physical
constraints. Mathematical programming includes several techniques such as dynamic
programming (DP), nonlinear programming (NLP), linear programming (LP), genetic
algorithms (GAs) and optimal control theory (OCT) (Hirad and Ramamurthy 2000).
Within the development of soft computing technique, optimal technique has
been used in number water resources issues. In this thesis, the author will use Fuzzy
technique combine with hydraulic model to develop an operation policy for multi-
purpose reservoir in an efficient way.
I.2. Problem statement
The Ma river basin is located in the North-West region of Vietnam, it borders
Laos on the West. The upstream basin is located in Vietnam, the middle basin is
located in Laos and the downstream is located in Vietnam. The Ma river basin is an
international basin. The catchment area of Ma river basin is about 31.060 Km2 of
which that in Vietnam is 20.190 Km2 (IWRP 2003). The Chu River is a main tributary
of the Ma River. It is located in the downstream area (IWRP 2003).
Based on potential water resources of this river system, many kinds of reservoir
such as single purpose and multi-purpose were built on the main river of the Ma river
system. The Cua Dat Reservoir is one of the biggest projects related to water resource
projects in Thanh Hoa province. The Cua Dat Reservoir is a multi-purpose reservoir.
Those purposes include as: to reduce flood peak and protect downstream area due to
probability of flood of 0.6% and control water level in downstream area at Xuan Khanh
station on the Chu river (under 13.71m) in high flow season; To supply discharge of
7.715 m3/s for domestic and industrial water demand; To irrigate about 86.862 ha
cultivated area; To generate electricity with capacity of 97 MW; To prevent salt water
intrusion lower than 1‰ at Ham Rong measured station (MARD 2013).
As mentioned above, the Cua Dat Reservoir has purposes are to supply water for
some water users such as hydropower generation, agriculture, industry, domestic and
environment. However, in dry season the increasing water demand of water users is
one of the important problems within water shortage in this river basin due to less
rainfall will enhance the conflicts among all the factors. In order to balance different
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water interests and solve the problems which related to using water, the Cua Dat
reservoir needs to optimize reservoir operation.
I.3. Objectives and Research questions
I.3.1. Objectives of the study
The main objectives of this research are:
- To optimize operation of the Cua Dat Reservoir in dry season, Thanh Hoa province
by using simulation model (MIKE 11 model) and optimal model (Fuzzy Logic
Technique).
- To provide management recommendations or alternatives and suggest appropriate
method of operation of the Cua Dat Reservoir in the Ma – Chu river basin.
I.3.2. Research Questions
1. What is Fuzzy logic theory and how to apply fuzzy logic in reservoir operation?
2. How to balance the water demand and water interests of the stakeholders in
operation of the Cua Dat Reservoir?
3. What are the objective functions and constraints in operation of the Cua Dat
Reservoir?
4. Does the Cua Dat Reservoir supply enough water for all of sectors in downstream
area regarding to current scenarios?
I.4. Structure of the thesis
This thesis structure includes those parts as below:
Chapter 1: This chapter discusses an overview of the study, the problem
statement and the objectives of the study are presented.
Chapter 2: This chapter reviews several researches of optimal reservoir
operation. Overview of hydrological model and optimization formulation are
presented. MIKE 11 model also is briefly introduced in this chapter.
Chapter 3: This chapter presents natural characteristic, natural conditions of the
study as well as population and economic characteristics of the study. Moreover, this
chapter also briefly introduces characteristics of the Cua Dat Reservoir and water
demand of each water user in downstream area.
Chapter 4: This chapter describes all kind of data collection and data analysis
which are used in this study. In this chapter, the author also shows the results of data
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calculation as the input of hydrological modeling and calculating water demand of each
water user in the downstream area. This chapter determines the objective functions and
all of constraint systems in the Cua Dat reservoir as well as using optimization model
to determine optimal rule curve (standard rule curve). Hence, the author also presents
MIKE 11 model set up for calibration and validation model and the results of routing
flow from the Cua Dat Reservoir by MIKE 11 model in this chapter.
Chapter 5: The results of optimal model and simulation model are shown in this
chapter through figures and evaluation tables. The chapter also analyzes the results
from two models in order to achieve the objectives of the study.
Chapter 6: This chapter also focuses on the main performances, conclusions and
recommendations for future studies.
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CHAPTER II
LITERATURE REVIEW
II.1. Studies on reservoir operation using optimal theory
Optimization is scientific field about best choice in some possible alternatives.
Optimal theory has been developed and investigated for many years over the world.
Optimization has been applied to a lot of fields in human life. Especially, in water
resource issues are used optimal theory as one of the effective tools for management
and decision making. Furthermore, optimization techniques have become increasingly
important in management and operations of complex reservoir systems. In reservoir
management, a lot of researchers have developed reservoir optimal operation during
the past four decades using dynamic programming (DP), linear programming (LP),
nonlinear programming (NLP), etc.(Cheng et al. 2008).
Rama and Sharad (2009) have developed operation policy for multi-purpose
reservoir in India using Neuro – Fuzzy technique including Fuzzy Mamdani and
ANFIS (Adaptive Neuro Fuzzy Interactive system). Their research determined
operation policy for monsoon period and non-monsoon period of Ramganga reservoir
and optimum releases against demands for domestic supply, irrigation and hydropower
generation. In other research, Omid et al. (2008) used optimal algorithm (HBMO-
Honey Bee Mating Optimization) for single and multi-purpose reservoir to minimize
the total present net cost of the system and maximum possible ratio for generate
electricity with installed capacity. In a case study of Hirakud Reservoir in Mahanadi
basin, India, D.Nagesh Kumar et al. (2009) used Folded Dynamic Programming (FDP)
to develop a long -term optimal operation policies for flood control. He showed that
FDP is a new search technique which can take care of all difficulties of other methods
to certain extend faced.
Long N.L et al. (2007) presented successfully a method as a tool for optimizing
operation of reservoir by using a combination of the simulation model and optimal
model. The authors optimized control strategies for the largest reservoir in Vietnam,
Hoa Binh Reservoir, in order to neutralize the conflicts in regulating water between
flood control and hydropower generation. The authors also organized two main
purposes in the flood season. With simulation model, they used MIKE 11 to guide the
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releases of the reservoir system according to the current storage level, the hydro-
meteorological conditions, and the time of the year. Afterward, the shuffled complex
evolution (SCE) algorithm was chosen as a perfect tool for optimizing the reservoir
operation. Babel et al. (2011) analyzed that the tradeoff between hydropower
production and environmental flow requirements for the hydropower system and the
impact of alternative scenarios of a hydropower system operation on energy production
and natural flow regime in the La Nga river basin in Vietnam. The authors used
different alternative operation policies to simulate the system by the Range of
Variability Approach (RVA) method. Hirad and Ramamurthy (2000) showed a new
composite algorithm as an alternative model to solve the problem related to the size of
reservoir when operating policy of multi-reservoir systems is applied based on
Pontryagin’s minimum principle.
Genetic algorithms have been widely applied in optimization to solve water
resources system. Cheng et al. (2008) used Chaos Genetic Algorithm (CGA) which
based on the Chaos Optimization Algorithm (COA) and Genetic Algorithm (GA) to
apply to the global optimum of the Rosenbrock function, the Schaffer function and the
optimal operation of hydropower station reservoir. M.Habese, Y. Nagayama (2002)
used Neural Network and Fuzzy System to optimize multi-purpose Dam of flood and
non- flood seasons. Base on their results, the fuzzy system is an effective operation
system when the major objective is water use. Besides that Network Fuzzy System is
effective for flood control. In other research, fuzzy mathematical programming was
used in research of Jairaj and Vedula (2001), their study area is a three reservoir system
in the upper Cauvery river basin, south China. As the results illustrated that, use of
fuzzy linear programming in multi-reservoir system optimization presents a potential
alternative to get the steady state solution with less efforts than classical stochastic
dynamic programming (Jairaj and Vedula 2001). Panigrahi and Mujumdar (2000) also
used Fuzzy Logic in their study to reservoir operation modeling, the case study of the
Malaprabha irrigation reservoir in Karnataka, India.
Besides that, there are many researches in reservoir operation in Vietnam. They
also used many optimization and simulation methods. Nghia T.T (2009) used
combination method between optimization and simulation model within advanced tools
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such as hydraulic dynamic model MIKE 11 and optimal technique GAMS. The
research had three major contents as follow: i) Determining water demand of water
users (such as Industry, Agriculture, Navigation and Environment); ii) Determining
upstream constraints of system due to periods; iii) Propose the operation process for
three reservoirs including Thac Ba, Hoa Binh, Tuyen Quang based on optimal
calculation in order to ensure that multi-reservoir can supply enough water for water
requirements in downstream. Hung N.T et al (2010) proposed models for optimal
operation of multiple purpose reservoir. The research proposed three distinct
alternatives including: i) Reservoir has mutual purpose for irrigation and hydropower;
ii) Reservoir’s major purpose is hydropower generation and second is irrigation; iii)
Reservoir has major purpose is irrigation and hydropower generation is second. Based
on models of the authors were built by using Delphi programming language and
applied Dynamic programming. The models were applied on Dinh Binh Reservoir
(Binh Dinh province) and A Vuong Reservoir (Quang Nam province). In other
research, optimization and simulation method were also used in the research of Tuyen
M.H (2009) for supplying water in dry season of reservoir system on Huong River
basin. The research combined GAMS optimization model and MIKE 11 hydraulic
dynamic model to control flow in downstream. The author illustrated that
environmental flow is about 31,5 m3/s in location of Thao Long Weir thoughout GAMS
optimal model. In dry water year with probability of 90%, the reservoir system can still
ensure the lowest discharge into dowstream area is 75m3/s.
Finally, optimization theories have been applied in a number of water resources
issues, especially in reservoir operation. Fuzzy logic technique is one of the useful
optimal tools for supporting reservoir operation and decision making. Using
optimization and simulation models in reservoir operation research are common over
the world. However, the Fuzzy Logic theory has been never applied in any research
about reservoir operation in Vietnam. That is reason in this research the Fuzzy theory
will be used as an optimization tool to optimize operation policy of Cua Dat Reservoir
thoughout objective function and constraints.
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II.2. Fuzzy logic theory
According to Rama and Sharad 2009, the Fuzzy logic is another area of artificial
intelligence. It has been applied successfully in different water resources applications.
The key content about fuzzy logic theory is that it allows for something to be partly this
and partly that, rather than having to be either all this or all that. The degree of
“belongingness” to a set or category can be described numerically by a membership
number between 0 and 1.0 (Rama and Sharad 2009).
In fuzzy logic theory, variables are “fuzzification” through the use of
Membership Function (MF) that defines the membership degree to fuzzy sets. These
variables are called linguistic variables. A fuzzy subset A of a universe of discourse U
is characterized by a membership function μA(x) in the interval [0,1] and represents the
grade of membership in A (Rama and Sharad2009).
The fuzzy objectives and constraints are characterized by their membership
functions. Membership functions are curves that define how each point in the input
space is mapped to a membership value (or degree of membership) between 0 and 1. It
can be of different forms including triangular, trapezium, Gaussian, B-spline, sigmoid
etc. Membership function can be symmetrical or unsymmetrical (Rama and
Sharad2009).
Fuzzy rule base system can be used as a suitable representation of simple and
complex physical systems. The fuzzy rule based model operates on an “IF–THEN”
principle, where the “IF” is a vector of fuzzy explanatory variables or premises and
“THEN” is fuzzy consequence. Fuzzy logic theory allows the user to capture
uncertainties in data. A fuzzy tool is available with the MATLAB software. Two types
of fuzzy inference systems including: Mamdani type and Takagi Sugeno type.
Fuzzy logic theory also has been used widely in modeling of reservoir
operation. According to Panigrahi and Mujumdar 2000 when applying fuzzy theory
need to follow several steps: (a) Fuzzification of inputs, where the crisp inputs such as
the inflow, reservoir storage and release, are transformed into fuzzy variables, (b)
Formulation of the fuzzy rule set, based on an expert knowledge base, (c) Application
of a fuzzy operator, to obtain one number representing the premise of each rule, (d)
Shaping of the consequence of the rule by implication, and (e) Defuzzification.
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Similarly, the Fuzzy logic will be used in this study for the Cua Dat reservoir
operation. And this is the initial research using the Fuzzy Logic in operating reservoir
in Vietnam.
II.3. Overview of hydraulic and hydrological modeling
Any scientific field always need a developed process including monitoring data,
recording and measuring data, simulation and explanation of natural phenomenon.
Hydrology is a science of water on the earth. To understand the hydrological events
can be described in laboratory by physical models. Based on theory and practice,
people have explained clearly the most of hydrological phenomenon such as rainfall,
infiltration, evaporation, and simulated them by hydrological models (hydraulic and
hydrological models).
Accordingly, hydraulic and hydrological models are tools to address the real
hydrological cycle in a simplified way. That kind of models are used for understanding
the hydrological processes as well as making hydrological prediction if there are some
water resources management and utilization activities are implemented (Tuan 2012).
The models are applied several algorithms to provide a quantitative relation between
the input data (e.g rainfall, meteorological data) and output (e.g runoff). The
mathematical models have been developed from 19th century with the simplest
rainfall-run off model by Mulvaney (1851) to more sophisticated models such as MIKE
Package developed by Danish Hydraulic Institute; Soil and Water Assessment Tools
(SWAT), HEC model developed by Hydraulic Engineering Center- USA; SIMONA
2D/3D hydrodynamic models by the Dept of Public Works and Delft 2D/3D by
WL|DELFT HYDRAULICS. Those models are used for simulation of flow, water
quality and sediment transport in estuaries, rivers, irrigation system, channels and
others bodies. They are fundamental to integrated water management as used for
planning and decision making (Tuan 2012).
The figure below shows the relationship between the various representations of
a model (Van Waveren et al 1999).
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The conceptual model is developed on the
basis of knowledge of the system and
serves as the basis for a mathematical
model. This model may be solved either
analytically or numerically. The model
reated is further refined into a model
program and finally into a Computer
Model by entering the proper input data.
(Van Waveren et al 1999).
Figure 2-1: Relationship between the
various representations of a model
Hydrological models have been used frequently in water resources planning and
management such as hydrological forecasting, reservoir operation, water quality,
research on flood, inundation and drought, designing irrigation system, supporting for
the integrated water resources management…etc. Appropriate model selection are
essential for each research or project. These selections should based on study
objectives, considering input data and output data, expected results and solutions.
There are many studies on water field that using model as an effective tool to solve
problems. According to Piman et al (2012), the authors used HEC and SWAT models
to simulate and evaluate flow changes from hydropower development and operation in
rivers: SeKong, Se San and Sepork of the Mekong basin. Long et al (2007) used MIKE
11 simulation model to set up control strategies for Hoa Binh reservoir operation. They
concluded that this model is an effective tool for optimizing complex system.
Bahremand and Smedt (2007) used distributed hydrological modeling (WETSPA) and
sensitivity analysis in Torysa Watershed, Slovakia to predict daily discharge value.
They also presented that a strategy by incorporating a model-independent parameter
estimator PEST for automatic calibration and sensitivity analysis.
In this study, MIKE 11 model will be selected to rout the flow, which is released
from the Cua Dat Reservoir operation to the downstream area in order to evaluate or
test discharge value within constraint system at control points. MIKE 11 model is a
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strong model. This model has been applied widely in Vietnam for many projects,
especially in field of water resources.
II.4. MIKE model
Many kind of hydraulic models have been applied widely in water resources
issues. MIKE 11 model is one of hydraulic models which have used popularly in
Vietnam. The MIKE 11 model has been developed by DHI water and environment
(Danish hydraulic institute). This model is a professional engineering software package
for simulation of flow, water quality and sediment transport in estuaries, rivers,
irrigation system, channels and others bodies (DHI 2011).
The study area has slope topography, short length of river and combine complex
rain regime to make flood regime change complicatedly. In this study, the author
selects the MIKE 11 model for routing the flow on the Ma-Chu river network. To apply
this model for study area, the understanding of model theory plays an important role.
The briefly description of the model theory according to DHI user’s manual as
following (Kmenl 2008):
The most commonly applied Hydro-Dynamic (HD) model is a flood
management tool simulating the unsteady flows in branched and looped river networks
and quasi two-dimensional flows in floodplains. When using a fully dynamic wave
description, MIKE 11 HD module solves the equations of conservation of continuity
and momentum (the ‘Saint Venant’ equations) as bellow:
Continuity equation:
Q
x t
A
(2-1)
(2-2)
q
Momentum equation:
Q2
A
Q Q
C2 AR
Q
t
h
x
gA g
0
x
Where:
Q: discharge (m3/s).
x: distance along flow direction (m).
g: gravity constant (m3/s)
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