Determination of Significance of Environmental Impacts of Development Projects: A Case Study of Environmental Impact Assessment of Indrawati-3 Hydropower Project in Nepal

doi:10.4236/jep.2011.28117

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Journal of Environmental Protection, 2011, 2, 1021-1031

doi:10.4236/jep.2011.28117 Published Online October 2011 (http://www.scirp.org/journal/jep)

Determination of the Significance of Environmental

Impacts of Development Projects: A Case Study of

Environmental Impact Assessment of Indrawati-3

Hydropower Project in Nepal

Ram B. Khadka1, Ajay Mathema1, Uttam Sagar Shrestha2

1School of Environmental Science and Management, Pokhara University, Nepal; 2Departments of Geography, Tribhuvan University,

Kathmandu, Nepal.

Email: [email protected], [email protected]

Received May 28th, 2011; revised July 7th, 2011; accepted August 26th, 2011.

ABSTRACT

The environmental impacts are commonly quantified in the EIA studies by rating, ranking and scaling. The National

EIA Guidelines , 1993, Nep al provides a guid eline to score th e impacts in terms of magnitud e, extent, and duration . Th is

step is commonly known as impa ct prediction in the EIA process. The predicted scores are multiplied b y the weightage

value of the resource likely to be affected. The application of the weightage transforms the predicted values of the im-

pacts into their “significanc e”—a concept used in the environmental decision making. In other words the significance

value entails assignment of relative judgment values to the impacts. The impacts, thus, can be ranked based on their

significance. The impact ranking is more useful in evaluating the socio-economic impacts. Unlike air, water and noise

quality, which can be assessed against established standards; the socio-economic impacts do not have standard scale

and are difficult to ra nk. Importance weighting of socio-economic impacts are commonly determined by the consensus

obtained fro m the interaction with th e local people, agencies, NGOs and experts. The impact ranking in the EIA process

is unavoidable, firstly to prioritize the urgent environmental issues and design mitigation measures accordingly and

also provide coherent linkages among the issues, and plan monitoring and auditing linkage with the proposed mitiga-

tion measures. Furthermore, it also provides strong basis for decision making, and thus facilitates the decision ma kers.

The process of impact predictio n, determination of sign ificance and ranking were applied in the EIA of Indrwati-3 Hy-

droelectric Project, which is one of the successful cases of EIA in Nepal. The authors believe that the impacts predicted

and quantified through this method are focused on the local concerns since it seeks an active involvement of the local

people who are likely to be affected.

Keywords: Environmental Impact Assessment, Environmental Significance, Ranking, Prediction of Impacts, Importance

Weighting, Judgment Values

1. Introduction

Environmental Significance is an anthropogenic concept

[1] used in decision making of the Environmental As-

sessment process. This concept remains undefined and

has become a source of controversy among the EA pro-

fessionals. Evaluation of the environmental significance

requires expert judgment values and scientific criteria [2].

However, EIA legislation of developed and developing

countries has catagorically mentioned that the law is en-

forcable only if the impact is environmentally significant.

The legal definition of environmentally significant in terms

of thresholds is usually not available [1]. Duinker and

Beanlands [3], Huge et al. [4], Sadler (1996), Gilpin [5]

and Thompson [2] have proposed various definition of

environmental significance and the common elements of

their definitions are following [1].

 Environmental significance is a judgment,

 The degree of environmental significance depends

upon the nature of the impacts (type, magnitude, ex-

tent and duration),

 The importance is based on biophysical and socio-

economic values, and the amount of changes to the

environment perceived to be acceptable to the com-

Determination of the Significance of Environmental Impacts of Development Projects: A Case Study of

Environmental Impact Assessment of Indrawati-3 Hydropower Project in Nepal

1022

munity.

Determination of the significan ce entails the assign ment

of relative judgment values of impact prediction associated

with the project and to determine the priority order in

which the impacts are to be avoided, mitigated or com-

pensated [6]. Evaluation of the significance of the pre-

dicted impacts can be made in different ways depending

on particular environmental component in question. For

example air, water and noise quality can be assessed against

the established quality standards whereas changes in socio-

economic conditions are more difficult to ev aluate [1].

The major elements of assessing the significant impacts

have been described for ecological and socio-economic

components and the assessment is mostly based on sub-

jective evaluation and includes the following [3]:

1) Ecological Component: This includes the criteria

related to ecology and environmental parameters criti-

cal to the operation of valued ecosystem such as

 Plant and animal hab itats,

 Rare, endangered and threatened species of biodiver-

sity,

 Ecosystem resilience, biodiversity and carrying ca-

pacity, and

 The viability of local species.

2) Social and Economical Components: Effects on

biophysical impacts when translated into human con-

cerns; the following effects are to be considered:

 Effect on human health and safety,

 Loss of commercially productive lands,

 Loss of public resources such as social services,

 Loss of transportation and other infrastructures, and

 Demography.

3) Environmental Standards: The use of national

standards enshrined into legislation/rules of the govern-

ment/agencies are the most common means to assess the

environmental significance. In most nations, standards/

criteria for air/water/noise are available fo r r e f erence [6].

While evaluating the impact significance, the current

status of the environment is analyzed. This is followed

by identification and prediction of potential impacts of

the proposed action. In the third stage, it is determined

whether the receiving environment will be able to absorb

the effects of the predicted impacts without suffering

irreversible change. This requires thorough understand-

ing of their resilience of receiving environment. It is also

required to evaluate whether the proposed proposal is

within the scope of national policy and covered by the

existing legislation and regulation and lastly the degree

of public interest [7].

2. Procedures for Determination of

Significance

Rau and Wooten [8] and Canter [9] have provided some

practical tools in evaluating environmental significance

of development projects. According to them, the effects

should be predicted in terms of magnitude, extent and

duration.

For the prediction, a number of ways have been pro-

posed such as symbolic signs, numerical values, (+) for

positive and (–) for negative effects, etc. However, the

most convenient way is to develop impact ranking

framework as proposed by Canadian Federal Environ-

mental Assessment Review [10]. National Environ-

mental Impact Assessment Guidelines. Nepal has also

adopted similar impact ranking method and applied suc-

cessfully in number of cases [11]. The impacts are pre-

dicted and classified in terms of:

Magnitude: It is determined based on severity of im-

pact. In case of high magnitude, the situation turns to be

irreversible. Medium and low magnitude is thus consi-

dered to be reversible and acceptable by the public.

The spatial extent: This is another characteristic of

the impact and indicates the zone of influence. The ef-

fects of the impacts may be of local or national or re-

gional or international scopes.

Duration of impact: This is the temporal aspects of

impacts, indicating how long the effects can last. Based

on the prediction made on the above characteristics of

the impacts, the following numerical values are assigned

to each of the character and the degree on which they are

likely to occur [11] (Table 1).

Each impact is predicted with its magnitude, extent

and duration and respective sco res. The to tal scores of all

three parameters are o ft e n computed.

Importance weighting schemes are the most structured

approach to impact scaling and permit direct transforma-

tion of impact ranking into impact significance. In order

to determine the appropriate weightings of the resource

expected to be affected, a procedure should be followed.

While assigning values for resources the EIA study group,

professionals, stakeholders, academicians, and know-

ledgeable people from the project area should be in-

volved in the series of meetings and discussions. An in-

teraction table is usually prepared where resources an-

ticipated to be affected should be listed on the vertical

column and the importance weighting should be marked

in the horizontal column with the degree of importance

from 1 to 3 where 1 indicates the least importance and 3

indicates the highest importance. Request should be

made to the participants to fill out the table based on

their own perceptions. The numerical values of the col-

umn are then summed up and individual value in the

column is divided by the total value. This gives relative

weighting of each resource to be considered [8].

The total score of magnitude, extent and duration is

Determination of the Significance of Environmental Impacts of Development Projects: A Case Study of

Environmental Impact Assessment of Indrawati-3 Hydropower Project in Nepal 1023

Table 1. Categorization of impacts and their ranking.

Magnitude Extent Duration

High/major ( H ) 60 Regional ®60 Long-term (L t) 20

Moderate (M) 20 Local (L) 20 Medium-term (Mt) 10

Minor (L) 10 Site Specific (SP) 10 Short-term (St) 05

Source: National EIA Guidelines, 1993.

multiplied by corresponding relative weightings of re-

source which is the significance of that particular impact.

In this way, significance can be determined for all the

impacts identified and further consideration for impacts

and mitigation measures can be proposed [6].

3. A Case Study on Determination of

Environmental Impact Significance of

Indrawati-3 Hydropower Project in

Nepal

Nepal is endowed with enormous hydropower potential.

However, only a small fraction of it has been exploited

so far. Additional quantity of power is required to fulfill

the power need of the country. Implementation of In-

drawati-3 hydropower was one of the responses to fulfill

the power need. The project started in 2002 and com-

pleted in 2007 and generated electricity which contri-

butes to National grid.

Indrawati-3 hydropower project was constructed in

Sindhupalchowk district located 58 km north-east of

Kathmandu-the capital city of Nep al. Th e head work was

built in the bank of Laps e River and the power house was

located in Ratmate village. The project covers three vil-

lage development committees viz Lagarche, Jaymire and

Bhotenamlang (See map Figure 1).

3.1. Project Area Description

The project is located within the mid-hills of mountain at

the altitude of 2000 m to 2500 m above the sea level. The

geology of the project area consisted mainly quartzite,

phyllities and schist. The sedimentation in river is quite

high and the specific load was recorded at 0.304 × 106

m3/year.

Indrawati is a snow-fed river originating from the Ju-

gal Himal range. The maximum flow of Indrawati River

near project area is 40.5 m3/sec in average and minimum

flow is 6.5 m3/sec recorded during the months of Febru-

ary to March. In the project area, a few patches of vege-

tation comprising particularly Lyonia ovalifolia, Pinus

ruxburghii, Alnus nepalensis, Castanopsis indica, and

Shorea robusta were present. Some species of the mam-

mals and birds were reportedly available in the area but

no rare, endangered and protected species were available.

Among the fish species in Indrawati River, 20 species of

the fresh water fish existed in the River with a few mi-

gratory species. The project area covered only three Vil-

lage Development Committees, consisting 7500 popula-

tions and were mostly farmers, traders, and service hold-

ers.

3.2. Project Description

The project consisted of 5-meter high diversion weir

constructed at the intake site, 2.9 km long headrace tun-

nel, a surface type of power house with 3 generating sets,

2.8 km long access road and accommodation complex

for workers and staff. The project was designed to divert

water flow of 17.2 m3/sec from the River to the tunnel

and the power house to generate electricity. As per the

rules 0.5 m3/sec of water flow has been released as envi-

ronmental flow for downstream during the dry period.

The project required occupying 120 ha of land. Most of

the land was acquired from the local farmers with ade-

quate compensation. Approximately, 1500 workers were

employed during the project construction and in the op-

erational stage, only 45 project staffs were employed

[12].

3.3. Environmental Impact Assessment (EIA)

As per the requirement Environmental Protection Regu-

lation of Government of Nepal [13], hydropower project

generating more than 5 MW required to undergo an EIA

process to obtain environmental clearance from the gov-

ernment of Nepal prior to the start of project construction.

Accordingly, an EIA was carried out for this project; for

which scoping and TOR documents were prepared and

were approved by the government on July 28 2004 [14]

The EIA study including public hearing was completed

on August 2005 and was submitted to the concerned

agency of the government for approval. The EIA was

approved by the government on October 2005. The pro-

ject was constructed and operated by a local Hydropower

company called “National Hydropower Company” [15]

and the electricity generated through this project is pur-

chased by Nepal Electricity Authority (NEA).

3.4. Methodology

After the approval of Scoping and TOR documents from

the concerned agency of the Government of Nepal, EIA

study was carried out. During the study, information on

the baseline condition s of the project area were collected

and compiled. Impact identification was made following

the methods given in National Environmental Impact

Guidelines, 1993 and particularly the following methods

were adopted [16]:

Determination of the Significance of Environmental Impacts of Development Projects: A Case Study of

Environmental Impact Assessment of Indrawati-3 Hydropower Project in Nepal

1024

Figure 1. Location of indrawati 3 hydropower project, Nepal.

 The use of structured questionnaires,

 Interaction Matrices; Simple Matrices and Leopold

Matrix,

 Use of GIS,

 Overlay techniques,

 Impact Networks,

 Task—specific Computer Models, and

 Ranking and weighting methods.

The second stage of the process predicting the impact

in terms of magnitude, extent and duration of each im-

pact identified. This was carried out through the inten-

sive interactions among professional experts, stake-

holders, and local people. A series of meetings were held

for impact prediction and finally they were accepted by

all.

Importance Weighing is the most structured approach

to impact rating. It permits direct transformation of a

sum of impact magnitude, extent, and duration into im-

pact significance. Importance weightings of the resources

likely to be affected were determined by organizing a

workshop or a meeting to discuss at which representa-

tives of the local people, local agencies, NGO stake-

holders and the technical experts involved in EIA study

have participated, A series of steps were followed by

each participant/organizer as given by Rau and Wooten

[8] while conducting meetings for the determination of

weighting. Total scores of prediction were multiplied by

importance weighting which resulted in developing a

framework for determining the impact significance.

Thus, determination of significance provided the im-

pact framework which contributed in the following:

 Categorization of impacts into most detrimental and

most beneficial,

 Prioritization of impacts for which major resources

Determination of the Significance of Environmental Impacts of Development Projects: A Case Study of

Environmental Impact Assessment of Indrawati-3 Hydropower Project in Nepal 1025

and efforts can be allocated for minimizing the effects

of highly detrimental impacts and enhancing the be-

nefits from highly beneficial ones, and

 Dropping down the insignificant impacts of project

implementation [6].

4. Results and Discussion

4.1. Identification of Environmental Impacts

Indrwati-3 Hydropower project constitute the construc-

tion of a water diversion weir, headrace tunnel, power-

house, and other ancillary infrastructures. In the process

of project construction and operation, the following ad-

verse and beneficial impacts were likely to occur.

Physical Impacts (Adverse and Beneficial)

Micro-climate and air quality

Topography, land use, and stability

Surface erosion

Disposal of excavated materials

Hydrology and Sedimentation

Water Quality/Pollution

Solid Waste

Noise and Vibration

Impacts on Biological resources

Loss of forest cov er

Increase in felling of trees

Exploitati on o f NTFP

Impact on Biodiversity

Impact on Rare Endangered and threatened

species

Impact on fish migration

Effect on Riparian Habitat

Downstream effect

Impacts on Socio-Economy and Cultural Resources

Impacts in agricultural land

Women and Child Labor

Culture and Religio n

Public Health

Occupational Health and Safety

Law and Order

Impact on local Life Style

Increase Pressure on Local Services

Increased local Employment

Increase in Local Trade

Improvement in Road Condition

Rural Electrification

Industrialization

Promotion in Eco-tourism

4.2. Predicting Anticipated Impacts

Based on the list above, the impacts were predicted. Each

impact was predicted in terms of magnitude, extent, and

duration. In predicting the impacts, ranking methods as

given in National Environmental Impact Assessment

Guidelines [11] and Canadian Federal Environmental

Assessment Review [10] were followed. As specified

earlier, a series of meetings were held with the participa-

tion of professional experts, stakeholders, affected peo-

ple, and beneficiaries. In the preliminary meeting, a list

of anticipated impacts was prepared and presented. The

meeting was attended by all the experts involved in the

EIA study. Each impact was discussed and predicted in

terms of magnitude, extent, and duration. Based on the

outcome of the preliminary meeting a Framework of

Impact Prediction (FIP) was developed and presented in

following meeting. A confirmation meeting was held

immediately upon the finalization of FIP. The opinions

and expressions of local p eople, local authorities, NGOs,

and other stakeholders present in the meeting were re-

corded. The final meeting of experts made the necessary

modifications to the predictions. The prediction made for

the anticipated impacts of Indrawati-3 Hydropower Pro-

ject are given in the Table 2:

4.3. Ranking of the Predicted Impact

Each of predicted impact is categorized into magnitude

extent and duration. Further, on the basis of severity,

impacts are classified as high (H), moderate (Mo) and

low (Mi) under magnitude, in which (H) is irreversible,

and (Mo) and (Lo) are reversible. Under the extent, im-

pact are classified as site specific (Sp), local (L) and re-

gional (R). Similarly under duration, impacts were clas-

sified into short term (St), medium term (Mt) and long

term (Lo). Each of the categories were the trans- lated

into numerical value as giv en in National EIA guidelines

(1993). The total numerical values were summed up to a

maximum of 140 and minimum up to 35 (Table 3).

4.4. Determining Importance Weighting

Importance weighting is a structured approach to impact

rating and permit a direct transformation of sum of im-

pact magnitude, extent and duration into impact signifi-

cance. Weighting can be determined by organizing a

workshop or a meeting represented by local people, local

agencies, NGOs stakeholders and the experts involved in

EIA study.

The meeting held on 25 January, 2002 assigned impor-

tance value to the resources to be affected. An interact-

tion table was prepared where resources anticipated to be

affected were listed in the vertical column and the im-

portance weighting was marked in the horizontal co-

lumn, indicating the degree of importance from 1 - 3

where 1 stands for the least importance and 3 indicates

the highest importance. Table 4 provides the overall

Determination of the Significance of Environmental Impacts of Development Projects: A Case Study of

Environmental Impact Assessment of Indrawati-3 Hydropower Project in Nepal

1026

Table 2. Impact prediction in terms of magnitude, extent and duration.

Impacts Magnitude Extent Duration

H Mo Mi R L Sp Lt Mt St

Physical Environment

Micro-climate and air quality - - Mi - - Sp - - St

Topography, land use and stab i li t y - Mo - - L - - - St

Disposal of excavated materials - Mo - - L - - Mt -

Hydrology and S e d i mentation - - Mi - L - - Mt -

Water Quality/Pollution - Mo - - L - - - St

Solid Waste - - Mi - - Sp - - St

Noise and Vibration - Mo - - L - - - St

Biological Environment

Loss of forest cover - Mo - - L - - Mt -

Impact on Biodiversity - Mo - - L - - - St

Impact on Rare Endangered and t hreatened species - Mo - - L - - Mt -

Impact on fish migration - - Mi - L - - Mt -

Effect on Riparian Habitat - - Mi - L - - Mt -

Downstream effects - Mo - - L - - Mt -

Socio-economic/Cultural Impact

Loss of agricultural land H - - - L - - Mt -

Women and Child Labor - Mo - - - Sp - - St

Culture and Religions - Mo - - L - - - St

Public Health - Mo - - L - - Mt -

Occupational Health and Safety - Mo - - - Sp - - St

Law and Order - - Mi - - Sp - - St

Impact on local Life Style - Mo - - L - - - St

Increase Pressure on Local Services - Mo - - L - - - St

Increased local Employment - Mo - R - - - Mt -

Increase in Local Trade - Mo - R - - - Mt -

Improvement in Road Condition - Mo - R - - - Mt -

Rural Electrification - Mo - R - - Lt - -

Promotion in Eco-tourism - Mo - R - - Lt - -

Decrease in Dependence on Fuel wood - Mo - - - - Lt - -

H = High, Mo = Moderate, Mi = Minor, R = Regional, L = Local, Sp = Site Specific, Lt = Long Term, Mt = Medium Term, St = Short Term (National Planning

Commission, GON and IUCN-The World Conservation Union, 1993).

framework for assigning importance. The individual

ranking of importance was then divided by the total score

of importance value which provided the importance weight-

ing of each resource to be affected by project implemen-

tation.

4.5. Determination of Significance of Predicted

Impacts in the Context of Indrawati-3

Hydropower Project

The total score of numeral value of prediction of each

impact (Table 3) was multiplied by importance weighting

given in (Table 4). The product gives the relative impact

of significance (Table 5). The higher the product, the

more effects are associated w ith it. The impacts were then

categorized and prioritized to invest greater efforts and

resources for mitigating significant detrimental effects,

while dropping down less significant effects.

4.6. The Prioritization of Impacts for Designing

Effective Mitigation Measures

Table 5 provides a framework for impacts prioritization

for designing an effective mitigation measures. Based on

Determination of the Significance of Environmental Impacts of Development Projects: A Case Study of

Environmental Impact Assessment of Indrawati-3 Hydropower Project in Nepal 1027

Table 3. The predicted impacts translated into numerical ranking as given by National Planning Commission, GON and

IUCN-The World Conservation Union, 1993. [11]

Impacts Magnitude Extent Duration Total

H Mo MiR L Sp Lt Mt St

Physical Environment

Micro-climate and air quality - - 10 - - 10 - - 5 25

Topography, land use and stab i li t y - 20 - - 20 - - - 5 45

Disposal of excavated materials - 20 - - 20 - - 10 - 50

Hydrology and S e d i mentation - - 10 - 20 - - 10 - 40

Water Quality/Pollution - 20 - - 20 - - - 5 45

Solid Waste - - 10 - - 10 - - 5 25

Noise and Vibration - 20 - - 20 - - - 5 45

Biological Environment

Loss of forest cover - 20 - - 20 - - 10 - 50

Impact on Biodiversity - - 10 - - 10 - 10 - 30

Impact on Rare Endangered and t hreatened species - 20 - - 20 - - 10 - 50

Impact on fish migration - - 10 - 20 - - 10 - 40

Effects on Riparian Habitat - - 10 - 20 - - 10 - 40

Downstream effects - 20 - - 20 - - 10 - 50

Socio-economic/Cultural Impact

Loss of Agriculture land 60 - - - 20 - - 10 - 90

Women and Child Labor - 20 - - - 10- - 5 35

Culture and Religions - 20 - - 20 - - - 5 45

Public Health - 20 - - 20 - - 10 - 50

Occupational Health and Safety - 20 - - - 10 - - 5 35

Law and Order - - 10 - - 10 - - 5 25

Impact on local Life Style - 20 - - 20 - - - 5 45

Increased on Pressure on Local Services - 20 - - 20 - - - 5 45

Increased local Employment - 20 - 60 - - - 10 - 90

Increase in Local Trade - 20 - 60 - - - 10 - 90

Improvement in Road Condition - 20 - 60 - - - 10 - 90

Rural Electrification improvement - 20 - 60 - - 20 - - 100

Promotion in Eco-tourism - 20 - 60 - - 20 - - 100

Decrease in Dependence on Fuel wood - 20 - - 20 - 20 - - 60

Source: National Hydropower Company Pvt, 2002; The values have been assigned as per the values given in National Environmental Impact Assessment

Guideline s (NPC Government of Nepal and IUCN , 1993).

Determination of the Significance of Environmental Impacts of Development Projects: A Case Study of

Environmental Impact Assessment of Indrawati-3 Hydropower Project in Nepal

1028

Table 4. Importance weighting as decided by exper t group (Extracted f ro m E IA of Indrawati-3 Hydropower Project).

Impacts Importance Value

Physical Environment 1 2 3 Total Importance Weighting

Micro-climate and air quality  1 0.01960

Geology and topography  2 0.03921

Hydrology and S e d i mentation  2 0.03921

Water Quality  1 0.01960

Solid Waste  1 0.01960

Tranquility of the area  2 0.03921

Biological Environment

Forest cover  2 0.03921

NTF  1 0.01960

Cultivated land  1 0.01960

Wild Life Habitat  2 0.03921

Rare Endangered and threatened species  3 0.05882

Fish species  2 0.03921

Riparian Habitat  1 0.01960

Socio-economic/Cultural Impact

Land property  3 0.05882

Women and Child  2 0.03921

Culture and Religions  2 0.03921

Occupational Health and Safety  2 0.02489

Law and Order  1 0.01960

Local Services  2 0.03921

Employment  3 0.05882

Water Use  1 0.01960

Local Trade  2 0.03921

Road Condition  1 0.01960

Rural Electrification  3 0.05882

Industrialization V 3 0.05882

Eco-tourism  2 0.03921

Total 51 1.000

Note: 1 = least importance, 2 = moderate importance and 3 = most important.

Determination of the Significance of Environmental Impacts of Development Projects: A Case Study of

Environmental Impact Assessment of Indrawati-3 Hydropower Project in Nepal

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Table 5. Impact significance and prioritization for mitigation prescription.

Predicted Impacts Total Score

from Ranking

(Table 3) Importance

Weighting

(Table 4)

Significant

Values Impact Prioritization

(1 = top priority)

Physical Environment

Micro-climate and air quality 25 0.01960 0.490 18

Topography, land use and stab i li t y 45 0.03921 1.764 9

Disposal of excavated materials 50 0.03921 1.960 8

Hydrology and S e d i mentation 40 0.01960 0.784 15

Water Quality/Pollution 45 0.01960 0.882 14

Solid Waste 25 0.03921 0.980 13

Noise and Vibration 45 0.03921 1.764 9

Biological Environment

Loss of forest cover 50 0.01960 0.980 13

Impact in Biodiversity 30 0.01960 0.588 17

Impact on Rare Endangered and t hreatened species 50 0.03921 1.960 8

Impact on fish migration 40 0.05882 2.352 7

Effect on Riparian Habitat 40 0.03921 1.568 10

Downstream effects 50 0.05882 2.941 5

Socio-economic/Cultural Impact

Loss of Agriculture land 90 0.05882 5.293 2

Women and Child Labor 35 0.03921 1.372 11

Culture and Religions 45 0.03921 1.764 9

Occupational Health Hazardous and Safety 35 0.01960 0.686 16

Law and Order 25 0.03921 0.980 13

Impact on local Life Style 45 0.05882 2.646 6

Increase Pressure on Local Services 45 0.01960 0.882 14

Increased in local Employment 90 0.03921 3.528 4

Increase in Local Trade 90 0.01960 1.521 10

Improvement in Road Condition 90 0.05882 5.293 2

Rural Electrification 100 0.05882 5.882 1

Promotion in Eco-tourism 100 0.03921 3.921 3

Decrease in Dependence on Fuel wood 60

0.01960 1.176 12

Source: N ational Hydropower Company Pvt, 2002.

priority and severity the predicted impacts were classi-

fied into following three categories:

Impacts having significant adverse/beneficial effects

Rural Electrification—beneficial

Local employment—beneficial

Promotion in Ecotourism—beneficial

Loss of Agricultural land—adverse

Disposal of excavated materials—adverse

Decrease in dependence on fuel wood—beneficial

Promotion of ecotourism—beneficial

Loss of forest cover/forest biomass —a dv erse

Impact on rare/endangered/endemic species of plants

and animals downstream effects—adverse

Topography, land use and stability—adverse

Noise and vibration—adverse

Habitat encroachment—adverse

Effects on culture and religious—adverse

Hydrology and sedimentation—adverse

Impact on fish migrati on— adverse

Impacts with Moderate/Adverse/Beneficial Effects

Occupational health hazards—adverse

Women and child labor—adverse

Exploitati on o f NTFP—adverse

Impacts on life style—adverse

Water quality / pollution—adverse

Effects on ripa ri a n habitat—adv erse

Impacts with Less Significant Adverse/Beneficial Ef-

fects

Improvement in road condition—beneficial

Law and order—adverse

Micro-climate and air quality—adverse

Solid waste—adverse

5. Conclusions

The entire process as outlined above for the identifica-

tion of significant impacts is a subjective exercises in-

volving mostly judgment values of experts, stakeholders,

project affected and beneficiaries and other concerned

people of the local area. But for those parameters of en-

vironment, whose national and international standards or

Determination of the Significance of Environmental Impacts of Development Projects: A Case Study of

Environmental Impact Assessment of Indrawati-3 Hydropower Project in Nepal

1030

norms are available, the values anticipated from the

study can be compared and the thesholds can be deter-

mined. For example, air and water quality and noise level

can be compared against national quality standards. For

impacts, whose severity is not quantifiable such as social

issues, this process of quantification, would be most ap-

propriate, since it involves the project affected stake-

holders of project areas. The authors believe that the im-

pact predicted and quantified through this method would

likely to be more closer to the reality of the local area,

since it involves the lo cal people likely to be affected by

the project implementation [14].

Determination of significance provides the impact

framework on categorization of impacts into most detri-

mental and most beneficial ones and prioritizes the im-

pacts for which major resources and efforts can be allo-

cated for reducing highly detrimental effects and en-

hancing benefits from highly beneficial impacts [6]. All

scores are relative and computation methods are based

on subjective judgment value. Therefore, it does not have

any scientific foundation [8]. However, in the process of

EIA of a development project, many impacts are usually

identified; some of them are significantly detrimental or

beneficial but most of them are insignificant in terms of

their severity, albeit, they are equally treated and wrongly

predicted. In such circumstances, the project proponent

faces dilemma as to where to place more resources and

efforts in order to minimize the detrimental effects or to

enhance beneficial effects of project implementation.

Therefore, categorization of impacts in terms of severity

is more desirable [14] for:

 Designing the most effective mitigation measures

investing adequate amount of time, money and efforts,

to minimize the most significant adverse impacts,

 Paying less attention and efforts on moderate and less

significant impacts,

 Providing a coherent linkage among the various is-

sues addressed in EIA report,

 Providing specific monitoring and aud iting linkage to

the specific impacts and mitigation measures pro-

posed, and above all, concentrating more on highly

significant impacts, thus, avoiding the insignificant

ones.

Furthermore, the quantification of impacts and their

categorization is important because the decision makers

usually require a strong basis to make a decision on the

proposed project implementation. It would be rather dif-

ficult for project proponent to convince the decision

maker through descriptive narration; but quantification

of the description is likely to ease the decision makers to

grasp the essence of the issues to be decided particularly

in developing country.

6. Acknowledgements

The authors are highly grateful to the Authorities of In-

drawati-3 Hydropower Project Nepal for the permission

to use their information. The help prov ided by the people

responsible for collecting information, the local stake-

holders who provided their valuable suggestions, and the

experts who examined the validity of the issues are

highly appreciated.

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