Evaluation Method of Alternatives
for River Improvement Project with Public Participation
加賀屋誠一 1・生駒絵里 2・内田賢悦 3
Seiichi KAGAYA1, Eri IKOMA2and Kenetsu UCHIDA3
1

Graduate School of Public Policy, Hokkaido University
Koken Engineering Consultant Ltd.
3
Graduate School of Engineering, Hokkaido University
2

Abstract
Recently we have discussed the alternative of river improvement which involves thenature of river as much as possible is chosen by inhabitants. However, it is difficult that thealternative puts together various awareness and ideas of the inhabitants. Therefore,
workshops have been carried out as a field of opinion exchange of inhabitants andspecialists. It is important to arrange the stage which collects information of the watershed
in order to make the opinions of inhabitants reflect. In this study, we developed evaluation
method of alternatives for river improvement project with public participation. The method
includes the selection of an appropriate basic improvement plan, the concern to its
improvement plan and the evaluation of specific visual alternative project, and an choice ofthe optimal project. The concrete procedure is composed of those methods andparticipation of inhabitants and workshops. The conclusions are 1) After the discussion inworkshops, they agreed to determine the policy of the excavation of mid-scale riverbed inexisting waterway as an appropriate improvement system. This was evaluated for the mostbalanced idea between the aim of flood control and that of environmental protection interms of fuzzy integral, 2) Such an idea was recognized by inhabitants through CVM basedon the questionnaire. The concerns for the policy were very high and the value of total
WTP was larger than the cost of a supposed improvement project and 3) Based on such afundamental comprehensive plan, several alternative projects composed of several factors
were proposed to inhabitants. As a result, the project taking the nature friendly method in
was the optimal project of all alternatives due to Conjoint Analysis. In such a way, we built
the process of decision-making involving administrative organization and community,
furthermore, the adjustment section- workshops. It is very important to adjust the different
opinions among some interest groups. Moreover, we introduced some effective methods as
supporting system of decision-making. Actually, we used fuzzy integral, CVM andConjoint Analysis. These are appropriate to analyze the ideas or opinions from inhabitants
and to guide scientific information to a common stage of decision-making.
Key Words: river improvement, public participation, fuzzy integral, CVM, conjoint analysis

11. INTRODUCTION
In Japan, since the new river law was established, it has been necessary to introduce thesynthetic improvement scheme including river environment in addition to flood control and water
use in the river development project. Planning system which reflects the opinions in the watershedshould be also introduced into the aim of river environment improvement and its conservation. Thatis, the improvement system should be promoted in response to needs for regional inhabitant. In
these years various discussions have been developed on building the methodology. The mostimportant thing is to complete the decision process of planning and to make public participation in
the process. In our past researches, some results were obtained for the establishment of new decision
process of planning. However, the more detailed examination on the method for accurately catching
information of the inhabitant is still needed. It is essential to study the public participation withaccountability for the method of river environment improvement.
The objective of this study is to make a method of building the alternative plans and to build aprocedure for determining the most appropriate improvement plan in terms of public participation.
2. PROCEDURE OF THIS STUDY
2.1 Concept of Procedure
Here, the procedure of this study was constructed as shown in Figure 2.1. The workshop
promotes some discussions based on the procedure. The workshop is composed of several interest
groups including residents, administration as an organizing body, planners, consultants, and NPO forregional planning etc..
First of all, several candidates of fundamental river improvement method are prepared. The
appropriate method is evaluated by means of Choquet’s Integral that is a kind of Fuzzy Integral.
Determine a fundamental river improvement method
Overall evaluation of project
Questionnaire for contingent valuable method (CVM)
Model-building for estimation ofwillingness to pay (WTP) No.1
Factors effects on WTP

Model-building for estimation ofwillingness to pay (WTP) No.2
By respondents having higher awarenessfor flood control projectSpecific alternative evaluation
Select Attributes and their levels by workshop
Visualize alternatives
Practice the questionnaire for conjoint analysis
Select the most appropriate alternative
Figure 2.1 Procedure of this study
Next, we confirm the inhabitants’ consequences asking the willingness to pay (WTP) for theriver improvement method. The overall evaluation of the method is examined by CVM. Actually2

we evaluate the estimate of WTP in terms of respondents’ attributes when we plan the river
improvement project.
Fundamental factors composed of the river improvement are devised in order to offer
information for the workshop. Next the alternative plans are composed of the factors and then areevaluated. Here, the preferential method for alternatives of the river environment improvement
project is examined simultaneously.
Visual expression of an alternative plan is devised in order to give a common image torespondents. Several visual alternatives obtained are composed of montage photograph and GIS
information.
Using this technique, it is possible to analyze the alternatives with high-gradereliability. The bias of the evaluation on alternatives is reduced in terms of the visualization. As
specific methodologies here, the conjoint analysis is introduced.
As an object area, the midstream of Tokachi River, which is called as Aioi-Nakajima District,
was selected. Tokachi River is located in the east part of Hokkaido, Japan.
2.2 Public Participation of River Environmental Improvement
Usually, river environmental improvement is executed by national or local government basedon the synthetic plan of a river basin.
More advanced plan they have, more dependent on theexecution the community is. As a result, the conflict often appears between them. Therefore, it isnecessary to make a communication system for acquisition of common information with each other.
This system is a kind of risk communication. We defined a workshop as a supporting group ofcommunication. We already developed a procedure of plan making process in view of SEA. SEA
is the formalized, systematic and comprehensive process of evaluating the environmental effects of apolicy, plan or program and its alternatives, including the preparation of a written report on thefindings of that evaluation, and using the findings in publicly accountable decision-making [1]. In
this study we examine a part of procedure from stage 1 to stage 3 as shown in Figure 2.2.
Here, the role of the workshop is important to prepare some basic information as follows:
1) Determination of overall framework: Based on the motivation proposed by the government, they
discuss the overall framework of project and devise the factors with relevant to it.
2) Determination of the evaluated alternatives: Based on the plan of the overall project, they selectseveral factors and comprise several alternatives using such factors.
3) Determination and confirmation of the optimal alternative: Based on the result of inhabitants’awareness, they discuss and confirm the optimal alternative plan of river environmental
improvement.
Concretely, the inhabitant interest is grasped as the river improvement project. The necessity ofriver improvement project is examined. And then, the effective factors which contribute tounderstanding of inhabitants are clarified. Moreover, the final aim is to build the decision-making
system for the river improvement plan which the inhabitants expect.

3Administration

Consultants & NPO etc.

Community(Process on(Process on support of decision)(Process on

execution of plan)

participation)
information managementsocial concerns

Proposal of improvement

Stage 1 (Problem-oriented)

Ideas

Diagnosis

Problem definition

Problem recognition

Problem finding & check

Offering existing data

Discussion on items
Establishment of frameworkof plan & selection ofthem

Prepare of decision-making

Response of importance
Problem structure &Policy determination

Evaluation of item importanceStage 2

Plan determination

among items(Alternative evaluation)

Data collection & survey
Choice of alternatives

Forecast of achievement

Choice of optimal plan
Satisfaction of alternatives
Stage 3
Program determination(Simulation & detailed check)

Simulation for project program

Specified plan of project

responsibility ofmanagement &participation

Figure 2.2 Procedure of plan making process in view of SEA
2.3 Support system in the adjustment stage(1) Residents participation system due to the workshop
The main adjustment stage is a workshop in this method. Here, the workshop is
composed of several interest groups including residents, administration as an organizing body,planners, consultants, and NPO for regional planning etc. in order to build a comprehensive plan
cooperatively. The adjustment stage by the workshop was proposed as shown in Figure2.3. A
purpose of the adjustment stage here is not only to propose the public participation method but also
to introduce workshop in the process of plan building and specifically to utilize it for making
alternatives.
1) Composition of the workshop: The workshop is composed of some groups. Here, the participantsfrom residents in the workshop are chosen by the public recruitment. The number of participants isabout 20 persons, and the final participant should be decided by the drawing from the applicants.

42) Present basic plan and its condition: The member of the administration did the information
disclosure of purposes, basic concept, planned goal, scales in the plan region, some relevant
constraints, etc., and the argued topics were given to workshop.
3) Execute each workshop: At first stage the contents of problem are chosen and adjusted.
Specifically, ideas are thought out due to brain-storming, and KJ method (morphological analysis
method) is introduced to adjust the ideas. In addition, a structural hierarchy is built by Fuzzy
Structural Modeling. It is composed of the items for the general river improvement project. And
then, the questionnaire is surveyed for evaluation of items. The utility analysis is executed using theimportance obtained by the questionnaire results. Conjoint Analysis is introduced for the analysis.
Moreover, the alternative plan is selected and those achievements are evaluated comprehensively atstage 2 and stage 3. As the result, the optimal plan is selected. Through the whole, the difference andsimilarity between workshop and residents around the study area is evaluated and then suchinformation reflects the decision of the workshop.
4) Present the alternative plan: The alternative plans are composed of evaluation items obtained by
the workshop. Here, the specified alternative plans are expressed in the visual form. In addition,
selection and adjustment of alternative plans are also carried out based on the information such asaccounted cost of a project.
5) Evaluate the alternative plan in each workshop; the information of preference is investigatedthrough discussion and adjustment in each workshop. In this study Fuzzy integral is supposed to use
as the comprehensive evaluation method. Fuzzy integral uses fuzzy measure consisted of thesubjective achievement and the relative importance of attribute.
Problem on improvement planning of river environment

motivation on planning

Preparation stage
Composition of workshop

recruit participants

Presentation of plan proposition and its conditions

administrative disclosureand release
operation of some sub-workshops and presentation of the results

adjustment stage 1
gathering and adjustment of ideas in workshop

discussion/choice of items/
introduction of BS and KJ
method and FSM/
evaluation of utility by
conjoint analysis

discussion of alternative plansadjustment in each sub-workshop
adjustment stage 2
proposition and evaluation of alternative plansadjustment in whole workshop

multi-criteria analysis/
Fuzzy integral
appropriate alternativedecision of appropriate alternative plan under whole agreement

visual presentation

Figure 2.3 Method for public participation in terms of workshop
2.4 Existing Condition of Study Area
The capacity of the river discharged flow in the district is insufficient on present state. That is,
the flow of the river is prevented in affects of the heavy rainfall, etc. in this district. As a result, theaffect reaches to the upstream seriously:

51) Tokachi River around the Aioi-Nakajima district has 7,100m3/sec as the planning flood flow. But
now it secures only 3,200m3/sec as the existing safe flow.
2)Aioi-Nakajima area is composed of a large sandbank. it is not possible that the flow run smoothly
because of high land level. Therefore in the upstream, water level increase when the flooding occurs.
It has a possibility of a large damage in the urban district caused by running over the levees. it is
only run.
3) In Aioi-Nakajima area there is no damage in life and property directly, because the inhabitant does
not live there when flooding occurs. However, it becomes necessary to execute the river
improvement for prevention of overflows and reduction of the damage from flooding.
Many trees such as the willow flourish in the river would prevent the flooding flow. Moreover thelarge zigzag of the river smoothly would not flow in the downstream. On the other hand, it isimportant to reserve the forest of a special kind of willow and rich nature such as the nesting place ofthe rare swallow, nevertheless urban suburban area existing in Obihiro City, Otofuke town,and
Makubetsu town.
3. ALGORITHM OF THIS STUDY
3.1 Method of grouped fuzzy structural modeling
In fuzzy structural modeling (FSM), the difference of importance between each item isindicated in continuous space of [0,1]. The algorithm of FSM is composed of estimating the direct
and indirect relationship due to fuzzy extensive principle and drawing the results using graph theory.
Here, the method was proposed to estimate the difference of importance in each item and to adjust
the values developed by Zarhariev et al [2]. First of all, let us explain the algorithm of determining
the preferential structure using fuzzy contributive rule. Let two preferential contents be ai and a j .
~We define the preference of a group by the following equation by using the contributory function C k .
This function represents the degree of contribution to the group preference.
(1)
ai Ra j iff C~mk (ai , a j ) > 0~
C mk (ai , a j ) = u~k (ai ) − u~k (a j )(2)

Where a relation ai Ra j means a i is superior to or equals a j for the decision maker k and issatisfied with connective and transitive conditions. The contributory function C~mk (ai , a j ) is the degreeof preference of the decision maker k in case of ai against a j . ～ represents fuzzy number. The
difference of importance in whole group is defined as minimum distance among each relationship asequation (3).
q(3)
R M = min d ( R, R )

∑
k =1

k

Where R1 , R 2 ,...., R k ,...., R q are fuzzy preference relations that express the decision-maker’s
estimations and let us assume thatµ R1 (ai , a j ) ≤ µ R 2 (ai , a j ) ≤ ......... ≤ µ Rq (ai , a j )(4)

We can determine the fuzzy relation R M as the group including member 1 to member k using
the median among the group like the following equation:µ RM (ai , a j ) = µ Rk (ai , a j ) , where k = (1 / 2)(q + 1) , if q is odd, (5)µ RM (ai , a j ) = ( µ Rk (ai , a j ) + µ Rk +1 (ai , a j )) , where k = (1 / 2) if q is even. (6)Thus fuzzy relation that is the nearest in the sense of Hamming distance to given fuzzy
preferential relations is determined by equation (4) to equation (6). The obtained variable µ RM (ai , a j ) isa median in total preferential relation and is defined as the minimum distance of every difference
between preferential relations. The matrix is composed of the total items m by each obtained relation.
Then, the direct or indirect influences are computed due to the Cartesian product of the matrix.
Finally the relational graph is indicated.
3.2 Fuzzy Integral as a Multi-Criteria Analysis - Choquet Integral

6

Fuzzy evaluation is based on the fuzzy integral using the degree of importance indicated byfuzzy measure [2]. Yager developed the theoretical evaluation method combined multi-criteria [3]analysis with the fuzzy evaluation. In the fuzzy multi-criteria analysis, we should obtain bothachievement of the evaluation criteria and their importance basically. Here, we introduce Choquet
integral as a kind of fuzzy integral. In the case of applying multi-criteria to planning like river
improvement project, the data are often ambiguity. So we should consider such characteristics.
Choquet integral is generally formulated as shown in equation (7).
∞(7)(c) ∫ h( x)dg = ∫ g ( x / h( x) ≥ α )dα0Equation (10) represents the integral with the function h : x → [0, ∞] .
When function h is represented asnh( x ) = (α − α ) χ ( x ) h : x → [0, ∞] , χ xi is defined function of set X i ,

∑
i =1

i −1

i

xi

(8)

Choquet integral is redefined as:n(c) ∫ h( x)dg = ∑ (α i − α i −1 ) g ( X i ) .

(9)

i =1

Where α i ; achievement of each attribute, g ( X i ) ; a set of importance, and0 ≤ α 1 ≤ α 2 ≤ ... ≤ α n , α 0 = 0 , X 1 ⊃ X 2 ⊃ ... ⊃ X n .

(10)

3.3 Contingent Valuation Method (CVM)(1) Environmental Value
The value of environmental quality is divided into use value and nonuse value. (sometimes
we consider positive use value as use value and passive use value as nonuse value ). The use value
is the value which is indicated by resource utilization and spatial utilization of the environment.
Moreover the use value can be classified into direct use value and indirect use value. The direct use
value is the value which is brought in case of consumption of resource from environment. The
indirect utility value receives the service from environment. Meanwhile the nonuse value does not
relate to the value mentioned above. Typical one is existence value. The existence value does notconnect with utilization at present or in the future both directly and indirectly. But it is given byindividual preference such that the environment would not be lost. It is called a peculiar value. In
addition, there are bequest value and option value that have both properties of use value and nonuse
value. The bequest value is a value for leaving environment and resources for the future generation.
It is also the value which is related to future utilization.
(2)Evaluation in terms of CVM
When there is originally no market on the evaluation, CVM makes a market imaginarily
and intends to consider it.
In this method, first of all, the contents of environment and administrative service are introduced to
the respondents. And then, willingness to pay is asked toward heightening the level of environment.
On the other hand, we can consider willingness to accept compensation if environment oradministrative service is declined. WTA is indicated as the necessary money to obtain the originalutility again. CVM can also evaluate both the use values and holdover value. Direct and indirect use
value and option value are measurable even in terms of usual consumer's surplus analysis andHedonic approach which is a kind of the analyses on the non-market material. But it is only possible
to evaluate the existing value in terms of CVM. The CVM is possible to estimate not only the valuesof substantial environment or administrative service but also their virtual values. On the basis of thequestionnaire supposed to the imaginary situation, it is possible to ask monetary values ofenvironment and the administration service directly. The questionnaire of WTP in CVM is divided
roughly into the following four methods.
1) Method due to free answer: to ask sum of payment freely.
2) Method due to bid price using game mode: to ask agree or disagree with the proposed price torepeat until obtaining the answer of No.
3) Method due to payment card system: to answer the appropriate value within some alternative
choices.

74) Method due to a pairing choice system: to ask agree or disagree with proposed priceThis study adopted the payment card system.
(3)Estimate Model of WTP
Suppose the probability of agreement with a given WTP price to Pr[ yes] , it is formulated as
Equation(11).

Pr[ yes] =1
1 + e − ∆V

.

(11)

where ∆V ; a difference of utility between proposed prices.
Here, supposed that Equation (11) is transformed into Equation (12), it can be estimated parametersof estimate equation by means of maximum likelihood method [4].
n

m

i =1

k =1

∆V = α + β T + ∑ γ i y i + ∑ δ k z k(12)

where α , β , γ , δ ; parameters,

T is a proposed price, y i ; variables of
attributes( i = 1, n ), and z ; variables of a respondent’s awareness ( k = 1, m) .

a respondent’s

3.4 Conjoint Analysis as Supporting Approach of Workshop
The alternatives handled in this study are combined of the multiple river improvement
measures. Each service level has also been considered from various categories. The conjoint
analysis is applied to planning fields, environment economics, etc. in these years [5]. The analysis
procedure is summarized as following aspects briefly:
1) Evaluated Attributes: Several attributes are introduced to determine the value of plans. Each
attribute is consisted of several levels. The alternatives are combined of the multiple river
improvement measures to increase environmental level of river basin. Each attribute is evaluated
due to utility value of some respondents. The evaluated levels of each attribute are considered as
various categories.
2) Comprise Profiles: The card called a profile is prepared and used. The profile is a lattice of thefactors composed of a series of attributes. This is specific plans consisted of multifactor. Each
attribute value (partial utility value) is evaluated by showing this profile to the respondent, andasking the whole utility of the profile,.
3) Analyze the Obtained Data:
Equation (13) represents an estimate of the whole utility.
p(13)(i = 1,2,....., n )rˆ = βˆ + ∑uˆ (k )where û (k ) ; an estimate of the partial utility of the level kji in the attribute j in the profile i. βˆ ; an
0

i

j

j =1

j

ji

ji

0

estimate of the constant parameter β 0 , and γˆi ; an estimate of the evaluation γ i for the evaluation
object (profile), and n ; a total number of the profiles, and p ; a total number of the attributes.
Moreover, importance score of attribute j for indicating the relative importance of each factor isshown in Equation (13). Here, RANGE is a difference between maximum and minimum of utility
value of attribute j in Equation (14) and Equation (15).
RANGE j(14)
IMPj = 100 p∑ RANGE
j =1

RANGE j = maximum of uˆ j ( k ji ) - minimum of uˆ j ( k ji )(15)

The remarkable advantage of Conjoint Analysis is to estimate how the value changes, when it
rearranged the value element of alternative plan, and when it added the new value element in it.
Namely, it is not only to clarify in which part there is a problem on the whole plans but also toestimate the variation when it measures the value by the decomposition of the whole plans at the
moment. Some river improvement plans are considered as the alternatives in the river basin. Based8on the approach, the preference measure of the citizen was surveyed in terms of the conjoint analysis.
The profiles with whole concepts are presented to the examinee.
4. EMPIRICAL RESULTS
4.1 Outline of Questionnaire Surveys(1) Attributes of surveyed residents and participants in the workshop
Table 4.1 Outline of questionnaire surveys to the inhabitants and to the workshop
Age
20-29
30-39
40-49
50-59
More than 60(%)
7(8)
20(13)
22(46)
28(23)
24(8)Distance
between Less than 4km-5.9km 6km-7.9km 8km-9.9km
More
than
dwelling and district
4km
10km
(%)
8
17
28
23
25
Consequence of flood Very
Important
FairlyNo
controlimportantimportantimportant
(%)
41
47
7
5
Consequenceof Very
Important
FairlyNonatural environment
importantimportantimportant
(%)
52
38
7
3
Notes: only number represents ratio of inhabitants and (number) shows ratio of workshop members
The questionnaire survey was executed to grasp the fundamental ideas from the inhabitants andthe workshop members. The ratio for attribute of both residents and workshop members are shownin Table 4.1. The inhabitants were selected from almost every generation and every occupation
equally. Most of them have much consequence for both flood control and conservation of naturalenvironment. The participants in workshop are from various occupancies, but in the generation of
forties [6].
(2)Analytical results of basic concepts to the general river improvement plan
On basis of the proposal of discussion and the adjustment of ideas due to KJ method, weanalyzed the hierarchical structure for improvement items of the concept.
Table 4.2 result of FSM analysis
respondent
Preference
structure bydegree ofimportanceresidents
A>E=F>B=C=D
Workshop member
A>E>F>B=C=D
Notes: symbol >: superior, symbol= indifference

legend: A: flood control, B: access to theriver site, C: communing the river nature, D:land use in the river, E: maintenance of
natural environment, F: protection of floraand fauna

Table 4.2 shows the result obtained from the survey for residents and workshop members.
This shows the flood damage prevention is the most important. Both the approach of naturalenvironmental conservation and flora and fauna protection are ranked at the next stage. It is similar
to the result of the survey due to the workshop participants. Namely, both groups think that the basic
items river improvement planning are significant. The items of the familiarity with river, the accessto riverside and the improvement of land use in the river are ranked at the bottom.
That is to say, large difference is not seen between residents and workshop members in thefundamental attitude on the river sustainable improvement.
(3)Analytical results due to conjoint analysis
Next, the specific problem on the alternative plan was considered. We proposed basic
alternatives which were built by several factors and their levels. As an analytical method, Conjoint

9Analysis was introduced to find combinational optimum plan with some partial utilities. The selectedfactors and their levels are shown in Table 4.3. On basis of these factors and levels, the profiles ofalternatives were drawn, and each profile was evaluated by full profile analysis. Factors here are
four contents, namely, the improvement for flood control, the improvement for communing withriver, the utilization of the land in riverside and the protective measure of flora and fauna. These
factors express the basic concept of the future plan in view of sustainability, and the level consists ofthe specific level proposed in the discussion.
The results of analysis brought the following findings as shown in Table 4.3.
1)The relative importance of residents was different from that of workshop participants. In case ofresidents, the protection of flora and fauna was the most important factor but workshop members
evaluated the improvement of flood control as the most important factor.
2) In case of the other factors, two groups had different ideas. That is, the residents thought that the
projects for river sustainable improvement should be promoted in the study area. But workshop
members thought that the area should be stood still. In other words, the environment in the rivershould be kept with the existing conditions.
Table 4.3 Factor and level introduced into the analysis.
FactorLevel 1
Level 2(attribute)
Improve flood control
existing Method of nature friendly
Commune with river

existing

Fishing and walking

Improve land use
Protect flora & fauna

existing
existing

Planting trees & green coverProtection of flora & fauna

Level 3
Conventional flood
controlBoating and outdoor
sportsNatural park

Table 4.4 Results due to conjoint analysis in case of workshop members
Factor(attribute)
Level
Partial utility
Relative importance
Improve flood control
Commune with river
Improve land use
Protect flora & fauna

Level 1
Level 2
Level 3
Level 1
Level 2
Level 3
Level 1
Level 2
Level 3
Level 1
Level 2

Residents workshop
-0.54
9.98
5.14
3.20
-4.00
-13.18
-2.33
8.40
0.95
-6.80
1.39
-1.60
-5.37
4.80
3.56
2.90
1.71
-7.70
-6.46
-4.50
6.46
4.50

Residents workshop
27.70

41.88

10.57

27.12

25.08

18.49

36.66

12.51

4.2 Evaluation of Alternatives in Workshops(1) Discussion of alternatives in workshop
In the Aioi-Nakajima area, workshops for river improvement have been opened since thebeginning of 2002. By the discussion in the workshop, the alternatives were obtained mainly as
excavation of the new waterway, excavation of the intermediate water channel, widening of theexisting waterway, etc.
It is shown in Table 4.5.

10

Table 4.5 Alternative discussed in the workshop
Alternative plan
Contents
Demerit and merit
1.Excavation of new/Excavation with straight line
/Impossible access to sandbank
waterway with straight line /Modification of waterway width /Risk of stoppage/Risk of destruction of bird nests
2. Excavation of mid-scale/Excavation intermediately with
/Use intermediate bed only on
riverbed in existingstraight line
flooding time
waterway/Construction of some ponds/Use ponds for application ofwithin riverflood control and water use/Possible access to sandbank
3. Expansion of existing/Expansion of existing waterway /Deforestationwaterway/Construction of floodwater/Risk of erosion in riversidestorage area
/Use ponds for application offlood control and water use
4. Expansion of existing/Expansion of existing waterway /Large-scaled deforestationwaterway and up-stream/Construction of stored/Risk of erosion in riverside
improvement
floodwater area
/Use ponds for application of/Change of waterway in upstream flood control and water use
5.Excavation of new low/Excavation of new shallow/Risk of stoppage due tohead waterwaywaterway
sedimentation/water flows along waterways at/Large cost of maintenance
usual time(2)Decision of the whole alternative project
Table 4.6 Evaluation of alternative projects due to Choquet integral
1) Important weight due to fuzzy measure

α 1 = 0 .25

α 1 = 0 .20

α 1 = 0 .16

α 1 = 0 .13

α 1 = 0 .35

2) Achievement degree of each item
Alternative project

Factor1

Factor2

Factor3

Factor4

Factor5

1.new channel excavation

0.8

0.1

0.5

0.1

0.5

2.mid-scale riverbed excavation

0.9

0.8

0.8

0.5

0.6

3.channel expansion

0.3

0.5

0.8

0.8

0.1

4.upstream control & channel expansion

0.3

0.5

0.8

0.7

0.1

5.new low-head channel excavation

0.7

0.3

0.6

0.5

0.3

3) Results of comprehensive evaluation
Alternative project

1

2

3

4

5

Evaluation value (order)

18.03 (3)29.52 (1)17.01 (4)16.51 (5)18.93 (2)The basic ideas on river improvement plan of residents and workshop participants were
grasped by discussion in workshop and support planning system. Alternative projects should be
evaluated relatively. Here, the alternative projects were mainly composed of five plans. The
evaluation items(factors) were selected such as i ) prevention of flood damage, ii)access to theriverbed, iii)substantiality of the communing with the river, iv)substantiality of the land use in the
district, and maintenance of the natural environment. Table 4.3 demonstrates these evaluation items
are evaluated in the continuous interval from 0 to 1. The larger the numerical value is, the higher the
expectation is. The degree of importance was also shown in Table 4.6.
The comprehensive evaluation was executed by using Choquet Integral. The results represent inTable 4.6 as well.

11

Alternative 2 was optimum plan as a result of analysis. That is, the mid-scale riverbed
excavation should be chosen as the optimal project. On basis of the result, the evaluation by
inhabitant around the study area is carried out. Another analysis mentioned that it became 1.5 billion
yen for improvement cost of the optimum plan by estimate.
4.3 Analysis due to CVM(1)Outline of survey for CVM
As mentioned in the previous section, we discussed the appropriate basic river improvement
plan in workshops. As a result, we could find a optimal plan for workshops. Based on such a plan,we examined if it would be accepted by inhabitants. The following suppositions were provided forinhabitants.
1) River improvement would be promoted as a new waterway in the sandbank, which has 400 meters
width and 2 meters depth.
2) A part of the budget would be provided by expense of the area in river basin for twenty years.
In this condition, we asked how much they would pay for promoting this project. On thesurvey, we adopted the paid card which is selected by inhabitants and all concept method for profile.
The obtained WTP is regarded as the necessity of the project. We also built the Logit model basedon random utility theory as the estimate model. By using this model, we can argue the inhabitant’sconsequences for river improvement with relevant to their attributes and awareness. In this way, theopposed answers towards expenses paid by tax were excluded.
60

number of samples

Number ofsamplesratio of agreement

%

100
90

50

80
70

40

60
30

50
40

20

30
20

10

10
0

¥1
,0
00
¥2
,0
00
¥3
,0
00
¥5
,0
0
¥1 0
0,
00
0

¥5
00

¥3
00

¥2
00

¥1
00

¥0

0

Figure 4.1 Results of calculation due to CVM questionnaire
Figure 4.1 demonstrates the distribution of respondents’ WTP. The simple average WTP isprovided for 2,516 yen.
The model discussed in section 3.2 was estimated by using maximum likelihood method. The
result is represented in Table 4.7. In this model the proposed WTP, annual income, consciousness offlood control contributed to the model strongly. In particular, the consciousness of flood control
influenced to the estimated WTP largely. In this case, smaller the discrete number represented thecategory of flood is, the higher the concern for flood control is.

12Figure 4.2 demonstrates WTP values in the different segments, that is, high-concerning group
and all the respondents. The difference between two groups is 1,235 yen as median. Inhabitants who
have the high-grade concerns for flood control also value high WTP. At the same time such
inhabitants have the experience of voluntary activity and flood drill activity simultaneously.
contents
Proposed sum β
Annual income γConstant αConcern to flood control
Age generation
Likelihood ratio
Hit rate (%)

Table 4.7 parameter in the model due to CVM
unit
parameter
T value
judgmentyen-0.0007-17***
1 to 5
1 to 71 to 50.481
84.64

0.17272.3077-0.8469
0.18572.253
6.536-9.305
3.169

**
***
***
***

mean
2.302
1.711
3.459

** 5% and *** 1% significance

100%
90%

average

80%
70%
60%

high concerns of flood
control

50%
40%
30%
20%
10%
0%
¥0

¥2,000¥4,000¥6,000¥8,000¥10,000¥12,000

Figure 4.2 Differences of WTP between the segments of concerns of flood control
Finally, WTP was estimated for total amount in the whole municipality. Table 4.8 shows thetotal amount of WTP. WTP per household is 2,682 yen in a year, and 37,900 yen for twenty years.
The total amount of WTP in the region is 279 million yen in a year, and 3,944 million yen for twenty
years. In this connection, the total cost is counted for 1,500 million yen to complete the river
improvement project. Therefore, the inhabitants require for the project, because the total WTP
exceed the total cost in the long term plan.
Table 4.8 Total amount of willingness to pay(WTP)
Annual WTP per household
2,682 yen
Accumulated WTP in twenty years per household
37,900 yen
Annual total WTP of residents in the district
279 million yen
Accumulated WTP in twenty years of residents in the district
3,944 million yen
4.4 Evaluated Results of Alternatives by Conjoint Analysis(1) Outline of Questionnaire
As mentioned above, it is necessary for inhabitants to promote river environmental
improvement. Here, the specific alternatives were assumed in terms of several attributes. Table 4.9
represents four attributes and their levels of category. Using these attributes and their levels, we
proposed eight alternatives combined with them to the respondents. The alternative which the13inhabitants desired was grasped in terms of this analysis. In this survey, the alternatives visualized
were adopted to be understood more easily.
Table 4.9 Attributes and their levels of Conjoint Analysis
Attribute (factor)
Level 1
Level 2
A. forests along riverside
Nature friendly method
Conventional method
B. trees in a waterway
Nature friendly method
Conventional method
C. ponds in waterway
Nature friendly method
Conventional method
D. roads along riverside
Nature friendly method
Conventional method(2) Analysis of Results by Questionnaire
Figure 4.3 shows the partial utility of each attribute.
evaluated utilities for method of nature friendly.
6

In all attributes, the inhabitants

nature friendly method
exisitng method

4

2

0

forests along
riversidetrees in awaterway

ponds in awaterwayroads along
riverside

-2

-4

-6

Figure 4.3 Partial utility of each attribute
Considering the importance of each attribute, trees in a waterway (B) and roads along
riverside (D) is evaluated for higher concerns. At the same time, the utility of Nature friendly
method is higher in every attribute than that of conventional method. Figure 4.4 represents theimportance of each attribute in terms of difference of flood drill activity. When inhabitants
experienced flood drill activity, they have more importance for forests along riverside and roads
along riverside.
On the other hand, when respondents do not have experiences of flood drill
activity, they have more important for trees in a waterway compared with the other attributes.
Figure 4.5 shows importance of attributes in terms of the difference of river environmental
improvement. The respondents who selected much of nature friendly method evaluated forests
along riverside for more importance, but ponds in a waterway for less importance relatively. The
respondents who have same rank for two methods evaluated trees in a waterway for more
importance, but forests along riverside relatively. Moreover, the respondents who preferred theconventional method evaluated road along riverside for more importance.

14

40%
35%
30%
25%
20%
15%
10%
5%
0%
forests along
riversidetrees in awaterway

ponds in awaterwayroads along
riverside

Figure 4.4 Importance of each attribute45

nature>existing
nature=existing
nature<existing

40
35
30
25
20
15
10
5
0
forest along
riversidetrees in awaterway

ponds in awaterwayroads along
riversidenature>existing: the concern of nature friendly method is larger than that of existing method
nature=existing: both concerns are almost same.
nature<existing: the concern of nature friendly method is smaller than that of existing method.
Figure 4.5 Importance of each attribute among segments of idea for river improvement
5. CONCLUSION
In this study, we developed evaluation method of alternatives for river improvement projectwith public participation. The method includes the selection of an appropriate basic improvement
plan, the concern to its improvement plan and the evaluation of specific visual alternative project andthe choice of the optimal project. The concrete procedure is composed of those methods andparticipation of inhabitants and workshops.

15

Analyzing and adjusting the specific river environmental improvement, we concluded thefollowing contents:
1) After the discussion in workshops, they agreed to determine the policy of the excavation of midscale riverbed in existing waterway as an appropriate improvement system. This was evaluated forthe most balanced idea between the aim of flood control and that of environmental protection interms of fuzzy integral..
2) Such an idea was recognized by inhabitants through CVM based on the questionnaire. The
concerns for the policy were very high and the value of total WTP was larger than the cost of a
supposed improvement project.
3) Based on such a fundamental comprehensive plan, several alternative projects composed ofseveral factors were proposed to inhabitants. As a result, the project taking the nature friendly
method in was the optimal project of all alternatives due to Conjoint Analysis.
In such a way, we built the process of decision-making involving administrative organizationand community, furthermore, the adjustment section- workshops. It is very important to adjust thedifferent opinions among some interest groups.
Moreover, we introduced some effective methods as supporting system of decision-making.
Actually, we used fuzzy integral, CVM and Conjoint Analysis. These are appropriate to analyze theideas or opinions from inhabitants and to guide a scientific information to a common stage ofdecision-making.
In the future study, the pilot system should be advanced and refined, adding more discussion
stage and more useful methods. And then, the risk communication in the field of river improvement
should be established in terms of the comprehensive system simulation.

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