FINAL REPORT - Sri Lanka · FINAL REPORT ENVIRONMENTAL ... Figure 3:8 I: Anchoring boats along the U/S slope of dam cause bund erosion and scouring ... D/S - Down Stream - Down Stream

DAM SAFETY AND WATER RESOURCES PLANNING PROJECT (DSWRPP)

Ministry of Irrigation and Water Resources Management

FINAL REPORT

ENVIRONMENTAL ASSESSMENT FOR REHABILITATION OF ANGAMUWA DAM

(DSWRPPAF/CS/QCBS/0305A)

By UNI CONSULTANCY SERVICES

UNIVERSITY OF MORATUWA

October 2015

Environmental Assessment for Rehabilitation of Angamuwa Tank Draft Final Report

II

TABLE OF CONTENTS

TABLE OF CONTENTS ............................................................................................................... II

LIST OF ANNEXES ................................................................................................................... IV

LIST OF FIGURES .................................................................................................................... IV

LIST OF TABLES ...................................................................................................................... VI

ABBRIVIATIONS ...................................................................................................................... VII

1. CHAPTER 01 : INTRODUCTION ........................................................................................ 1

1.1 Project Description and Justification ..................................................................... 1

1.1.1 Background of the Project................................................................................ 1

1.1.2 Project Location ................................................................................................. 1

1.2 Scope of the Project and Environmental Assessment ....................................... 4

1.2.1 Scope of the Project ......................................................................................... 4

1.2.2 Environmental Assessment Requirements ................................................... 4

1.3 Objectives of the Study ............................................................................................ 4

1.4 Strategies to be Applied .......................................................................................... 4

1.5 Methodology .............................................................................................................. 5

1.5.1 Mobilization ........................................................................................................ 5

1.5.2 Scoping Meetings and Reconnaissance Visits ............................................. 5

1.5.3 Data and Information Collection ..................................................................... 5

1.5.4 Baseline Surveys ............................................................................................... 5

1.5.5 Institutional Arrangements ............................................................................... 7

1.5.6 Environmental Impact Analysis, Proposed Mitigatory Measures .............. 7

1.5.7 Documentation Procedure ............................................................................... 8

1.6 Expected Outcomes of the Report ....................................................................... 11

2. CHAPTER 02 : DESCRIPTION OF EXISTING ENVIRONMENT .......................................... 12

2.1 Overview .................................................................................................................. 12

2.2 Physical Environment ............................................................................................ 12

2.2.1 Climate .............................................................................................................. 12

2.2.2 Topography ...................................................................................................... 13

2.2.3 Soil and Geology ............................................................................................. 14

2.2.4 Hydrology.......................................................................................................... 15


III

2.2.5 Flooding ............................................................................................................ 21

2.2.6 Noise and Vibration ......................................................................................... 21

2.2.7 Air Quality ......................................................................................................... 21

2.2.8 Water Quality ................................................................................................... 23

2.3 Biological Environment with Flora and Fauna ................................................... 23

2.3.1 Existing Habitats in the Project Affected Area ............................................ 23

2.3.2 Existing Flora and Fauna in the Tank and Surrounding Habitats ............ 23

2.3.3 Ecological Signifcance of the Proposed Borrow Areas ............................. 27

2.3.4 Migratory Paths................................................................................................ 29

2.4 Socioeconomic Environment ................................................................................ 29

2.4.1 Local Administrative Units in the Project Area ........................................... 29

2.4.2 Land Use in Different Areas of the Irrigation Schemes ............................. 30

2.4.3 Demographic Data Relevant to the Project Area ....................................... 30

2.4.4 Economic Activities of Project Related Population .................................... 32

2.4.5 Other Water Uses............................................................................................ 34

2.5 Current Environmental Issues of the Project Area ............................................ 35

2.5.1 Physical Issues ................................................................................................ 35

2.5.2 Ecological Issues ............................................................................................. 35

2.5.3 Socioeconomic Issues .................................................................................... 35

3. CHAPTER 03 : PROPOSED INTERVENTIONS ................................................................. 36

3.1 Proposed Engineering Interventions ................................................................... 36

3.2 Proposed Borrowing Activities and the Identified Borrow Sites ...................... 40

3.3 Proposed Interventions that could Affect Neighboring Communities ............. 41

3.4 Proposed Interventions that could affect the Natural Habitats ........................ 41

4. CHAPTER 04 : PROJECT INDUCED IMPACTS ................................................................ 42

4.1 Identification of Project Induced Impacts ............................................................ 42

4.2 Quantification of their Significance ...................................................................... 55

5. CHAPTER 05 : ENVIRONMENTAL MANAGEMENT PLAN ............................................... 56

5.1 General Overview ................................................................................................... 56

5.2 Identification of Impacts and their Mitigations .................................................... 56

5.3 Implementation Schedules of Proposed Mitigation ........................................... 75

5.4 Formal Clearances and Approval Needed ......................................................... 76


IV

6. CHAPTER 06 : MONITORING PLAN ............................................................................... 77

6.1 Environmental Compliance and Monitoring ....................................................... 77

7. CHAPTER 07 : COST ESTIMATE OF ENVIRONMENTAL MANAGEMENT PLAN .............. 82

8. CHAPTER 08 : CONCLUSIONS AND RECOMMENDATIONS ............................................ 84

8.1 Conclusions ............................................................................................................. 84

8.2 Recommendations ................................................................................................. 84

LIST OF ANNEXES

Annex 1: Details of the Farming Community ......................................................................... II

Annex 2: Details of the encroached farmer families ............................................................. IV

Annex 3: Land area in Gravity and Lift irrigation systems in Angamuwa tank ........................ vi

Annex 4: Details of the cost benefit of an acre of paddy land in Angamuwa tank ................. vii

Annex 5: Annex 5: Map showing the vicinity of Angamuwa tank………………………………viii

Annex 6a & b: Location map for the identified quarry and borrow sites for Angamuwa tank .. ix


V

LIST OF FIGURES

Figure 1:1: Location Map of the Angamuwa Tank (Source: Survey Department, 1:50,000

Topo sheet) ........................................................................................................................... 2

Figure 1:2: Google Map Showing the access to Angamuwa Tank from Anuradhapuraya ...... 3

Figure 2:1: Monthly Average Rainfall in Rajanganaya tank catchment area during 2009 -

2014 (Source Divisional Irrigation Office, Rajanganaya) ..................................................... 13

Figure 2:2: Contour Map of the Project Area (Angamuwa Tank is locted beneath 40 m

contour line) ........................................................................................................................ 14

Figure 2:3: Distribution of Soil Groups (Panabokke, 1975) .................................................. 15

Figure 2:4: Land Use and Hydrological Features of the Angamuwa Basin .......................... 17

Figure 2:5: Location Map and Associated Hydrologic Features of Angamuwa .................... 18

Figure 2:6: Catchment of Mahavilachchiya within Modaragam aru-Uppu Aru Main Basin ... 19

Figure 2:7(a): Catchment of Angamuwa within Modaragam aru-Uppu Aru Main Basin ....... 19

Figure 2:8 (b): Catchment of Mahavilachchiya within Angamuwa aru-Uppu Aru Main Basin 20

Figure 2:9: Vegetation on the Dam...................................................................................... 24

Figure 2:10: Water logged or marshy lands in the downstream area of the tank bund......... 25

Figure 2:11: Rocky outcrop and associate vegetation ......................................................... 25

Figure 2:12: Tank and Irrigation canals ............................................................................... 26

Figure 2:13: Proposed gravel borrow area .......................................................................... 28

Figure 2:14: Proposed borrow site for earth extraction ........................................................ 28

Figure 3:1.1A: Washed away U/S slope and rip rap collapsed in some areas ..................... 38

Figure 3:2 B: Seepage areas along the D/S toes ................................................................ 39

Figure 3:3 C: Water stagnating at the dam .......................................................................... 39

Figure 3:4 D: Encroachments at the dam ............................................................................ 39

Figure 3:5 F: The bund road is with lots of pot holes and eroded places ............................. 39

Figure 3:6 G: Structural failures of the spillway such as failure of abutments, sliding of

sections............................................................................................................................... 39

Figure 3:7 H: Leakage through right wing wall of sluice and suspected areas in U/S .......... 39

Figure 3:8 I: Anchoring boats along the U/S slope of dam cause bund erosion and scouring

........................................................................................................................................... 40


VI

List of Tables

Table 1.1: The Method used for Impact Assessment............................................................. 6

Table 1.2: Work Plan............................................................................................................. 9

Table 2.1: Maximum Permissible Levels for air pollutants as given in The National

Environmental (Ambient Air Quality) Regulations, 1994 (amended 2008), and actual

measured air quality in Anuradhapura Town ....................................................................... 22

Table 2.2: details of the local administrative units related to the project .............................. 29

Table 2.3: Details of Project Relevant Population ................................................................ 31

Table 2.4: Distribution of Income Generation Activities among Families in Project Related

Villages ............................................................................................................................... 33

Table 2.5: Details Expressed by the Farmer Leaders .......................................................... 34

Table 3.1: Current issues in Angamuwa Tank Bund ............................................................ 36

Table 3.2: Location Details of the Identified Borrow Sites .................................................... 40

Table 4.1: Possible Impacts due to the Proposed Interventions and their Significance........ 43

Table 5.1: Proposed Mitigatory Measures for the Identified Impacts ................................... 57

Table 5.2: Formal Clearances and Approval Needed .......................................................... 76

Table 6.1: Summary of Monitoring Requirement ................................................................. 78

Table 7.1: Cost Estimate of EMP ........................................................................................ 82


VII

ABBRIVIATIONS

AMSL - Average Mean Sea Level

BPL - Below Poverty Level

CEA - Central Environment Authority

D/S - Down Stream - Down Stream

DBH - Diameter at Breast Height

DEM - Digital Elevation Model

DS Division - Divisional Secretariat Division

DSWRPP - Dam Safety & Water Resources Planning Project

EA - Environmental Assessment

EMP - Environmental Management Plan

EN - Species - Endangered Species

EPL - Environmental Protection License

FD - Forest Department

FFPO - Fauna and Flora Protection Act

GND - Grama Niladari Division

GoSl - Government of Sri Lanka

GPS - Global Positioning System

GSMB - Geological Survey and Mines Bureau

GTOP030 - Global 30 Arc=Second Elevation Data-Set

ICTAD - Institute for Construction Training and Development

ID - Irrigation Department

IDF - Intensify Durative Frequency Curve

IDF Curves - Intensity Duration Curves

IEE - Initial Environmental Examination


VIII

IML - Industrial Mining License

IUCN - International Union for Conservation of Nature

LB - Left Bank

KPI - Key Performance Indicators

MSL - Mean Sea Level

NEA - National Environmental Act

PM - Project Manager

PO - Project Office

PS - Pradeshiya Sabha

RB - Right Bank

STRM - Global Multi Resolution Terrain Elevation Data

TEC - Technical Evaluation Committee

ToR - Term of Reference

U/S - Up Stream

VU Species - Vulnerable Species

WB - World Bank


IX

TEAM OF CONSULTANTS FOR EA STUDY

Name Position

Eng. (Dr.) Mahesh

Jayaweera

Environmental Engineer/Civil Engineer (Team Leader)

Eng. (Dr.) Jagath Manatunge Natural Resources Management Specialist

Dr. Anusha Kasige Ecologist (Flora, Fauna and Ecosystems)

Mr. K. Jinapala Sociologist/Socio-economist

Uni-Consultancy Services Project Management


1

1. CHAPTER 01 : INTRODUCTION

1.1 Project Description and Justification

1.1.1 Background of the Project

Over 350 large/medium dams, headwork and trans-basin canals of Sri Lanka are aging and

suffering from various structural deficiencies and shortcomings in the operation and monitoring

facilities. Thirty-two dams have been identified as high risk with respect to their appurtenant

structures and operational efficiency. Those dams are required to have immediate interventions so

as to decrease the vulnerability of downstream populations and socioeconomic infrastructure, if

breached. This situation threatens the safety and operational efficiency of the dams and their

appurtenant structures and as a result increases the vulnerability of breaching.

The Dam Safety & Water Resources Planning Project (DSWRPP) intends to address these issues

through its dam safety and operational improvement component with financing from the World

Bank. The main objectives of the proposed project are to improve the development and

management of water resources within the country, reduce water induced hazards to public, and

enhance the effectiveness of water related investments. The proposed project intends to address

these objectives in 29 dams through its dam safety and operational improvement component.

For these objectives are to be met, there will be some interventions to be carried out. These

interventions may bring about environmental degradations, environmental issues in terms of

physical, ecological or/and social changes, alterations or irreparable losses. Hence, the project

needs to identify such environmental issues that are very likely and they should be reduced or

curtailed as practical as possible. The proposed assignment is therefore meant to address such

issues and the whole exercise is defined by the Term of Reference (ToR) which sets out the likely

problems associated with five dams that are operated by the Irrigation Department and Mahaweli

Authority under whose jurisdiction remedial actions would be proposed. The dams have been

selected based on comprehensive risk assessment studies carried out as part of project preparation

from a list of vulnerable dams in order to ensure their structural and functional safety. With the ToR

it is expected to carry out Environmental Assessments for the proposed interventions under the

DSWRPP for Padaviya, Angamuwa, Mahavilachchiya and Mahakanadarawa dams.

The World Bank (funding Agency) and Dam Safety & Water Resources Planning Project

(DSWRPP) have agreed that the four dams earmarked for rehabilitation under this study need only

an Environmental Assessment (EA) together with an Environmental Management Plan (EMP) as

the proposed rehabilitation works do not entail any significant civil works.

1.1.2 Project Location

The Angamuwa tank bund operates under Irrigation Department and located in the Anuradhapura

district and the Rajanganaya Divisional secretariat (DSD) of the North Central Province (Figure 1.1

and Figure 1.2).


2

Figure 1:1: Location Map of the Angamuwa Tank (Source: Survey Department, 1:50,000 Topo sheet)

Angamuwa

Tank


3

The Angamuwa tank is a medium size tank which operates under Anuradhapura Regional by

Rajanganaya Divisional Irrigation Engineer (DIE). This tank can be accessed through

Anuradhapura - Kebithigollewa Road (Figure 1.2).

Figure 1:2: Google Map Showing the access to Angamuwa Tank from Anuradhapuraya

The Angamuwa dam is an ancient dam built across a tributary of Kalaoya and restored in 1956.

This is an Earth dam having a length of 1,700 m and the maximum height is 8 m. The U/S and D/S

slopes are 1:2.5, FSL is 211 ft msl and the HFL is 215.6 ft msl. The capacity of the reservoir is

12,800 ac. ft and the irrigable area is 2,466 ac. The spillway of the dam is of masonry ogee type

with a length of 234 m which consist of 02 radial gates. The dimensions of the radial gates are 20ft

x 10ft and the sluice is located at the right end of the dam which made up of rubble masonry. The

water release from Angamuwa tank is feeding lower part of the Rajanganaya command area, while

feeding the RB main canal of Rajanganaya reservoir.


4

1.2 Scope of the Project and Environmental Assessment

1.2.1 Scope of the Project

The technical scope of the study is to carry out an environmental assessment based on the

identified interventions and their associated issues for the Angamuwa dam. The interventions to be

carried out during the rehabilitation work have already been defined at the inception stage of the

project based on the conceptual designs done by respective engineers. The present study focuses

on conducting the Environmental Assessment covering physical, ecological and socioeconomic

environment.

1.2.2 Environmental Assessment Requirements

This environmental assessment is prepared in pursuant to the World Bank’s Environmental

Safeguard Policies as outlined in OP/BP 4.01 and that of Safety of Dams OP/BP 4.37.

The overall objective of the proposed environmental assessment is to carry out the following

conforming to the World Bank’s Environmental Safeguard Policies and Procedures. For each dam,

an Environmental Management Plan will be prepared to address the objectives specified as given

below.

1.3 Objectives of the Study

The objectives of this assignment are to:

i. Identify and evaluate the potential environmental impacts that would arise as a result of the

proposed interventions

ii. Recommend appropriate mitigation measures to avoid, minimize, remedy or compensate

for the predicted negative impacts; and

iii. Provide a site-specific Environmental Management Plan that would give adequate project

options in terms of mitigation measures, project alternatives and a monitoring program to

achieve overall environmental sustainability of the project.

1.4 Strategies to be Applied

The strategies on which the environmental assessment will be done are based on the World Bank

Safeguard Policies and the National Environmental Act (NEA).

These environmental assessments are prepared in accordance with the World Bank’s

Environmental Safeguard Policies OP/BP 4.01 and that of Safety of Dams OP/BP 4.37. No

environmental assessment is required in accordance with NEA as the interventions do not belong to

categories that require either IEE or EIA. This had been confirmed by the Central Environmental

Authority.


5

1.5 Methodology

1.5.1 Mobilization

The team of experts from Uni Consultancy Services of Moratuwa University commenced work on

20th November, 2014 with a meeting of team members where the Team Leader briefed the team

members on the methodology for executing the consulting services. Documents required for the

study were also identified and team members were requested to collect those pertaining to their

areas of expertise. The team leader thereafter prepared the Scope of Work for all team members to

ensure that the quantum of work to be carried out would be done in an appropriate manner.

Documents pertaining to the ecological resources of the project area, topography, climate, geology,

soil, demography and other relevant data were collected and reviewed as an initial activity. The

reconnaissance survey was carried out from the 23rd to 25th of November 2014. The team visited all

the dams and their project areas. The team visited on individual capacity several times to gather

and collate necessary data from time to time.

1.5.2 Scoping Meetings and Reconnaissance Visits

The Consultants visited the five dams to observe the present conditions of the dams and to

understand the nature of the issues (Table 3.1). Initial discussions were held with the engineers and

other field officers in the Irrigation Department to gain clear understanding of the issues mentioned

in the ToR and to gather related information and design details that were available at the times of

visits.

1.5.3 Data and Information Collection

A detailed literature review of available data was done by the team of consultants at the project

initiation. Relevant data to identify impacts were collected during a reconnaissance visit as and

when available, and also desk studies. The data gaps were identified and the detailed field plan

was prepared to carry out baseline surveys.

1.5.4 Baseline Surveys

The study area of the assessment included the dam area, peripheral area (500 m minimum),

borrow areas, work site and any area beyond the project site where there is potential for

environmental impacts and off-site locations affected by construction activities.

Most of the physical assessment was restricted only to the exact sites where interventions are

applied and in some of the borrow sites. Erosion, flooding, noise and vibration issues, air quality

issues, water pollution potential, etc. were some of the attributes that were studied under the

physical assessment. Rainfall data, flood data if available, data on soil and geology, noise levels

were collected in order to understand the existing situation of the tank area.

An ecological survey was carried out to describe the existing baseline conditions to evaluate and

illustrate the magnitude of the problem. This identified the major habitats / flora and fauna in and


6

around the sites and to assess possible ecological impacts, existing environmental problems within

the proposed project areas. The study area was confined to the specific locations and immediate

surroundings directly affected by the activities. Under this part of the study, all trees of larger size

that need to be felled down were identified. The borrow areas were too scrutinized for the same

purposes in order to ensure no invasive species are transferred to the project site.

Methodology of social assessment mainly included the field visits of the sociologist and his

supporting staff with the other disciplinary team members that helped to gather primary and

secondary data. The stakeholders such as Irrigation Department, farmer organizations, fishing-

community, Grama Niladhari, affected people, beneficiaries and other direct and indirect users of

water in the reservoir were consulted to obtain data and their concerns related to the proposed

project. The Farmer Organization leaders and some general farmers were interviewed and the

details of them are shown in Annex 1.

Social surveys and related studies were carried out covering all the stakeholders, especially the

farmers and fishing communities in addition to other water users (e.g., villagers who use the water

for day-to-day activities, and/or other purposes). Grama Niladharis, Economic Development

Officers, Samurdhi Niyamakas, officials of the farmer organizations, and any other governmental

officers who are directly or indirectly involved with the functioning of the dam and its water

resources (such as the Divisional Secretariat, Irrigation officials, Agrarian Services Department etc.)

were also contacted. Data and information gathered from such social surveys were based to

identify and assess social impacts. Mitigation measures were proposed with clear justifications

based on the expectations of the stakeholders.

The socioeconomic data analysis was focused on the existing beneficial uses that would be

impacted due to each proposed development intervention. The method used for impact assessment

is mentioned in Table 1.1.

Table 1.1: The Method used for Impact Assessment

Issue to be dealt with Indicators Data Need

Livelihoods of the farming

community

No of farmers to be affected

The land parcels to be affected

(encroached land in the

downstream and upstream of the

reservoir)

under Details of cultivators the

tank, yield and income, details

on encroachments of the

reservations.

Other indirect livelihoods

No of water users affected

No of farming facilities affected

No of families using tank water for

bathing and washing

Data on the other water uses in

the tank


7

Issue to be dealt with Indicators Data Need

Disturbance to other

routine activities of the

communities in the project

area

No of people of the villages using

the tank bund as the access road

Data on users of the tank bund

as access road

1.5.5 Institutional Arrangements

The Acts, regulations, licenses, permits and other approvals that may be necessary for the

implementation of the proposed interventions were identified. These may include;

i. Irrigation Ordinance No. 32 of 1946 Irrigation (Amendment) No. 1 of 1951 Irrigation

(Amendment) No. 48 of 1968 Irrigation (Amendment) No. 37 of 1973 Agrarian

Development Act, No. 40 of 2002

ii. The National Environmental Act (NEA) No. 47 enacted in 1980 and NEA Amendment Act

No. 56 of 1988

iii. National Environmental Protection and Quality Regulations under extraordinary gazette

notification No. 1534/18 and No. 1533/16 of 2008 under NEA section 32 & 23A, 23B

iv. Fauna and Flora Protection Act (FFPO) No.2 of 1937 amended in 1993 and 2009

v. Felling of Trees Control Act No. 9 of 1951 as amended through Act No. 30 of 1953

vi. Water Resources Board Act, No. 29 of 1964 and (Amendment) Act, No. 42 of 1999

vii. Soil Conservation Act, No. 25 of 1951 and Amended No. 24 of 1996

viii. Agrarian Development Act No. 46 of 2000 (Section 32)

ix. Antiquities Ordinance No. 9 of 1940 and amendments

x. Mines And Minerals Act (No. 33 of 1992)

xi. Mahaweli Authority of Sri Lanka Act of 1979

xii. World Bank Guidelines pertaining to Dam Safety & Environment Assessment Guidelines

It is also imperative that the proper institutional arrangement be made available for smooth

operations of the EMP. It is the Project Office that is in charge of the entire project and the client,

Irrigation Department would be solely responsible in getting the project implemented with a selected

contractor. The contractor will be selected through a bidding process and the contractor is

responsible in implementing the EMP delineated herein this report. During the project

implementation period, the World Bank and the Project Office will evaluate the implementation of

the EMP. Once the EMP is implemented as per the World Bank Safeguard Policy Documents,

review of implementation of EMP would be done in order to ensure that all negative impacts are

addressed successfully.

1.5.6 Environmental Impact Analysis, Proposed Mitigatory Measures

Environmental impacts of the proposed project were identified during field investigations and

through the analysis of project interventions. Their significance was assessed on physical,

ecological and socio-economic resources due to project activities during construction and operation

phases. The World Bank Environmental Safeguard Policies and applicable GoSL laws and

http://www.google.lk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=8&cad=rja&uact=8&ved=0CEEQFjAH&url=http%3A%2F%2Fwww.commonlii.org%2Flk%2Flegis%2Fnum_act%2Fmama33o1992221%2F&ei=YmuCVNHlD5eMuATbs4HYBg&usg=AFQjCNEhIH82JksvJcDE_Qr5pQlavkMTPA&bvm=bv.80642063,d.c2E


8

regulations were followed in identifying and quantifying such impacts.

A site-specific EMP that would provide mitigation strategies, project alternatives and a plan for

monitoring program was prepared. Proper management of the catchment and the watershed that is

essential for ensuring continued economic benefits envisioned from the dam was paid due attention

in quantifying the impacts. These were also considered in the EMP.

1.5.7 Documentation Procedure

The following documents are to be prepared and delivered to DSWRPP.

i. Inception Reports for each Dam

Already submitted to the Project Office and approval was obtained.

ii. Draft Final Reports for each Dam

The Final Report includes the following:

a. A comprehensive Environmental Management Plan (EMP) to manage the on-site as well

as off-site environmental impact comprising mitigation strategies for each impact identified

b. Appropriate institutional arrangement to implement the proposed measures

c. Implementing schedule

d. Reporting procedures

e. Cost estimates for implementing mitigation measures

f. An environmental monitoring plan that will specify monitoring indicators to measure the

performance of the each mitigatory measure, monitoring mechanism and frequency.

g. Clearance approvals needed by the project prior to its implementation

h. Recommendations on the adequacy of the assessment

i. Final conclusions and recommendations in response to environmental viability, of the

project based on the findings

j. Annexure and Appendices

iii. Submission of Final Reports

The Final Report will be submitted within two weeks after receiving comments from the client once

the TEC evaluates and reviews the Draft Final Report. The final report will be reviewed by the

World Bank as well.

The main activities to be followed to complete above deliverables are summarized in Work Plan

given below (Table 1.3).


9

Table 1.2: Work Plan1

Activity Month Nov

’

201

4

December

2014

January

2015

February

2015

March 2015 April 2015

Week 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4

1 Primary Data Collection

2 Reconnaissance Survey

3 Meetings to discuss about

intervention/designs

4 Develop the detailed methodology

5 Scoping of environmental impacts

6 Submission of the Inception Report

7 Detailed field visits (Chapter 2 & 3)

8 Assessment of Anticipated Environmental

Impacts (Chapter 4)

1 Submission date of the Final Report is extended to the 25th of April 2015 in the meeting with DSWRP Project Officials held at Mahaweli Authority on 12th Feb. 2015


10

9 Formulation of the Environmental

Management Plan (Chapter 5)

1

0

Identification of needs/approvals to

implement EMP (Chapter 5)

1

1

Drafting of Environmental Monitoring Plan

(Chapter 6)

1

2

Cost Estimates (Chapter 7)

1

3

Compilation of Conclusions and

Recommendations (Chapter 8)

1

4

Compilation & Submission of the Draft

Final Report

1

5

Compilation & Submission of the Final

Report

.


11

1.6 Expected Outcomes of the Report

The expected outcomes are categorized as follows.

a. Comprehensive Environmental Management Plan (EMP) to manage the on-site as

well as off-site environmental impacts

b. An environmental monitoring plan that will specify the monitoring indicators to

measure the performance of the each mitigatory measure, monitoring mechanism

and frequency

c. Clearance approvals needed by the project prior to its implementation

d. Recommendations on the adequacy of the assessment

e. Recommendations regarding the environmental viability of the project based

findings


12

2. CHAPTER 02 : DESCRIPTION OF EXISTING ENVIRONMENT

2.1 Overview

It is imperative that the existing environment in the project area and the borrow areas are

identified in terms of different environmental elements. In order to perceive the likely

alterations of the existing environment due to the proposed interventions present status of

the existing environment needs to be recorded and then the impacts on such elements need

to be discussed.

In general, the entire existing environment is described in three main components, namely,

physical, ecological and socioeconomic environments respectively. Data were collected

focusing on these three components and are presented below.

2.2 Physical Environment

2.2.1 Climate

The Angamuwa tank is located in dry zone where the environment of the area consists with

dry and hot climatic conditions throughout the year. The climate of the Angamuwa is typical

to that of Anuradhapura district.

Temperature, which is warm throughout the year, shows little variation over the year and

between places in the district. The annual average temperature is 27.3oC. Humidity is an

important climatic consideration, which expresses the degree of dryness or wetness of the

air. The relative humidity varies in 70 – 82% within the year.

The rainfall generally follows a bimodal pattern of distribution. The major one of the two

rainfall peaks is spread over a period of three months commencing between late September

and mid October and extending to late December or up to mid January. These are called as

Maha rains, and due to relatively long period of rain filling the tanks and even causing

floods. As the Maha rains fade away, a dry season sets in during which period there is little

or no rain, in March soil dries up, the forest becomes less lush and the season turns less

tranquil. During the dry season decline the water reserves within the district. The second

rainy season of the year begins any time from mid March to mid April and lasts until May or

even June, which is called Yala rain corresponding to Yala season. This is shorter

compared to Maha rain. This rain replenishes the depleted tanks and ground water reserves

to a substantial level. When the short wet season is over, dry weather sets in again from

May or June. In August, the condition of the climate is arid, tanks are dried up, and the mud

is lined cracked. However, this district receives an annual average rainfall of 1,420 mm,

which is high enough in Maha season and mainly by North East monsoonal component.

The monthly average rainfall recorded in the Rajanganaya tank catchment area, which is the

closest rainfall station to Angamuwa tank, for the last 5 years is shown in Figure 2.1.


13

Figure 2:1: Monthly Average Rainfall in Rajanganaya tank catchment area during 2009

-2014 (Source Divisional Irrigation Office, Rajanganaya)

Unlike rainfall the temperature, which is warm throughout the year, shows little variation over

the year and between places in the district. The annual average temperature is 27.3oC.

Humidity is an important climatic consideration, which expresses the degree of dryness or

wetness of the air. The relative humidity varies between 70 – 82% within the year. During

the South Western monsoons, the wind speed accelerates to 12 km/hr or it rises further to

16 km/hr.

2.2.2 Topography

The general topography of Sri Lanka comprises of three distinctive peneplains or erosion

plains made up of a central highland massif rising above 2,500 metres in altitude and a low

gently undulating plain surrounding it and extending to the sea. The lowest peneplain

extends from the coastline to approximately 20-30 kilometres inland in a steep step of about

300 meters above mean sea (MSL). Angamuwa is located in the North Central Province,

lies within this lowermost peneplain. The landscape in the vicinity of the site is characterized

by flatlands, with almost no altitude changes, partly due to the fact that the land has already

been cleared and prepared for the agriculture, secondary development with people in-

migrating to these areas recently. According to the pre-existed topography, the elevation in

the proposed site area had varied from 110 m MSL in the northestern boundary to 40 m

MSL in western edge, with a gently sloping landscape in the western and south-west

direction (Figure 2.2).

0

100

200

300

400

500

600M

on

thly

ave

rage

Rai

nfa

ll (m

m)

2009

2010

2011

2012

2013

2014


14

Figure 2:2: Contour Map of the Project Area (Angamuwa Tank is locted beneath 40 m

contour line)

At a larger scale, the present topographical variation is somewhat different. The elevation

towards the south eastern areas (Tambuttegama) have higher ground propagating up to 100

m, whereas south western areas have lower elevations dropping to below 40 - 50 m towards

Kalaoya and Wilpattuwa area (western direction). The downstream of the tanks is

characterized by very gentle slopes with 0.5% – 1.0 % surface gradient in the north-western

direction (Figure 2.2).

2.2.3 Soil and Geology

According to the Geomorphological Map of Sri Lanka (1987/88), the area is located between

the boundary of hornblende gneiss and low plantation surfaces with thin soils (dry zone).

The soil types that are dominant in the area are dominantly reddish brown earth, low humic

gley soils and non-calcic brown soils (see figure 2.3) and regosols and alluvial soils in some

places in the subsurface layers. Predominant rocks are Precambrian, essentially gneissic

and crystalline rocks. Main rocks are Vijayan and Wanni series rocks of the Precambrian

and the Palaeozoic eras.

Up to 90% of the subsurface geological structure of Sri Lankan territory mainly consists of

highly crystalline, non-fossilifferous rocks of Precambrian age with a history of over 500

million years. The broad coastal plains of south-western Sri Lanka, along with the southern

India, are founded on these basement rocks (mainly basic igneous intrusive) on the lower

margin of a broad syncline which tilts downwards to the southwest and also known as one of

the most stable parts of the earth’s crust of the Indian shield. On the basis of the rock types


15

and structure, they are divided into three main complexes; namely, Highland Complex (HC),

Wane Complex (WC) and Vijay an Complex, and one subordinate unit Kadugannawa

Complex (KC).

Soils in the proposed site area are mainly of Non Calcic Brown with the top soil texture

varying from dark brown and dark grayish brown to brown or yellowish brown in the

subsurface layers. Predominant rocks are Precambrian, essentially gneissic and crystalline

rocks. Main rocks are Vijayan and Wanni series rocks of the Precambrian and the

Palaeozoic eras.

Figure 2:3: Distribution of Soil Groups (Panabokke, 1975)

2.2.4 Hydrology

The hydrology in the proposed site area is mainly governed by seasonal streams, cascade

system man-made reservoirs and associated irrigation canals. Surface water resources in

the project area mainly consist of inland reservoirs, which are used for water storage,

irrigation, and drinking water supply. Many such small reservoirs are located to the south

along the 2.0 km borderline and several minor tributaries of length 0.3-0.6 km are found,

draining the relatively high stretches in the middle of the 2.0 km radius circle peripherally

outwards in the downstream direction. Dendritic drainage pattern could be observed in the

area, with several waterways and man-made canals inter-connecting small reservoirs and

irrigation service canals via anicuts and sluices. Groundwater is used for daily needs

through dug wells. The depth of the groundwater table in the vicinity of site area is known to

vary from 3 m to 5 m and a definite seasonal variation could be expected in the groundwater

table following the rainfall regime.

According to the terrain contour layout, the gravity drainage in the proposed site area is in

western direction (Figure. 2.2), which is linked to the lower valleys of Aruvi-Ara and


16

Modaragam aru- Malwathu Oya. However, it is noted that there is no proper off-site

drainage route provided at present and the entire drainage from the surrounding area is

naturally channeled either to the small stream (North-West or conveyed to North-East

direction, across the sloping ridge. Due to the subsequent leveling and land preparation

activities carried out at site with stepped land plot set up with slopes maintained in north-

west direction has restored the similar flow regime with same flow directions. However, it

was noted that the surface drainage and culverts provided at the site at present are under

designed and tend to over flow even during regular rain events.

The main data required for the hydrological and hydraulic assessments apart from the

topographic information are;

Rainfall Intensity-Duration-Frequency Curves (IDF Curves) for catchment areas

Information on runoff coefficients and time of concentration

The site is situated in the belt of monsoon climates and governed by its tropical location as

well by the monsoonal regime, thus rainfall exhibits a strong seasonal variation. The area

falls under the dry zone and receives a long-term mean precipitation of which 75%

expectancy value of annual precipitation is > 900 mm. More than 50% of the total rainfall is

received during the Second Inter Monsoon and North-Eastern Monsoon (October to

December).

The sub-catchment area is presumably not subjected to any flooding under seasonal

monsoonal storm event, except for extreme events where backwater flows from downstream

accumulation due to flow constrictions may cause localized temporary inundation in some

areas. Historical flood data are not available in the area.

The topographic data with contours and road layout has been obtained from the Survey

Department. Topographic maps with 1: 50,000 scale were primarily used (1: 10,000 maps

were not available) together with the collected Global Positioning System (GPS) coordinates

to locate the manor canals and structures while supplementary topo - and land use

information from Google Earth maps, Google terrain data and other relevant images have

also been obtained as required. The SRTM/GTOPO30 (USGS) global raster satellite DEM

(Digital Elevation Model) data were downloaded and used in identifying sub-/major

catchments in the region. These maps and terrain data in combination with identified land

use data were used to distinguish and demarcate respective catchment areas for the tank

under consideration. In the present version of the analysis, a 5.0-m interval contour map in

the coastal to upstream regions, developed based on DEM data from GTOPO30 and

modified with SRTM (Refined) arc 3.0 data has been used in initial catchment demarcation

(Figure 2.3 – 2.8).


17

Figure 2:4: Land Use and Hydrological Features of the Angamuwa Basin


18

Figure 2:5: Location Map and Associated Hydrologic Features of Angamuwa


19

Figure 2:6: Catchment of Mahavilachchiya within Modaragam aru-Uppu Aru Main

Basin

Figure 2:7: Catchment of Angamuwa within Modaragam aru-Uppu Aru Main Basin


20

Figure 2:8 : Catchment of Mahavilachchiya within Angamuwa aru-Uppu Aru Main

Basin


21

2.2.5 Flooding

Past flooding records indicated that the project area was flooded particularly in the recent

past for a height of 2-3 feet. However, water level recedes soon after the rainfall ceases as

the direct catchment seems to be small compares to those of adjacent ones. However,

during flooding, people in the area find difficult to travel in the area.

The ground level of the project area is about +60 m above MSL and the surrounding low

lying valley, manmade water bodies, and natural waterways are at about +60 - 70 m above

MSL. No past records are available on occurrence of flooding and return periods, however,

the water levels had not reached beyond 60 m above MSL, even in the aftermath of

torrential rains in January-February 2011 that triggered unprecedented floods in

Anuradhapura and other nearby districts, also causing a large number of reservoirs to reach

their spill levels simultaneously, presumably for the first time in recent history after a similar

event in 1958 (Source: Irrigation Department, Ministry of Irrigation & Water Resources

Management, Sri Lanka). Available past rainfall records indicate that the accumulated

precipitation in the February 2011 event surpasses the 60-year return period flood event.

Therefore, no risk of flood inundation is foreseen in the proposed site area.

No past records are available on occurrence of flooding and return periods in the proposed

site area. However, minor floods have been recorded in the downstream valley area once in

3-4 years with up to 1 – 2 feet (0.3 – 0.6 m) of stagnant water due to downstream control of

increased water level in the inlet to Mahavilachchiya Wewa, however the maximum

inundation period was less than 2-3 days, during such recent flood events.

No records are available of occurrence of floods of this magnitude in the area for the past

100 years. However, the low lying flatland surrounding a section of the main entrance to the

site resembles a natural depression and seemingly becomes flooded during heavy rains,

causing a temporary problem of inundation.

2.2.6 Noise and Vibration

Background noise levels in the area were found to be very low varying in the range of 40 –

54 dB (A) during the site visit, indicating that no any artificial noise levels be generated in the

project area. The existing noise levels are attributed by the noise generated from the rattling

of leaves of trees by the wind and the occasional screech of birds passing and roosting in

the area.

No significant vibration levels were perceived during the field visit indicating that vibration

induced activities were almost absent.

2.2.7 Air Quality

Air quality in the entire study area appears to be good. However, there is a chance of


22

deteriorating temporarily the air quality along the transport routes due to traffic congestions.

The major source of atmospheric pollution in the area is from road traffic especially heavy

vehicles in the form of diesel and petrol engine vehicle fumes. Domestic sources of air

pollution will include emissions from burning of forest patches for Chena cultivation, wood

and kerosene burning stoves in settlements, villages and town areas. Also, emanation of

dust from the gravel quarry sites existing in the project area would contribute to air pollution.

Any such emissions will be very well dissipated in the open terrain and absorption by forest

vegetation. Air quality parameters measured in Anuradhapura city is presented in Table 2.1.

Since the surrounding areas of the proposed site is mostly surrounded by the homesteads,

small forested patches and rural settings, the ambient air quality in the vicinity should fall

within the limits of The National Environmental (Ambient Air Quality) Regulations, 1994

(amended 2008). Ambient air quality had been measured by the Central Environmental

Authority in 1999 (reported in Environmental Atlas of Sri Lanka in 2005), and their

observations are included in Table 2.1.

Table 2.1: Maximum Permissible Levels for air pollutants as given in The National

Environmental (Ambient Air Quality) Regulations, 1994 (amended 2008), and actual

measured air quality in Anuradhapura Town

Pollutant Maximum Permissible

Level

Air pollutant levels measured in

Anuradhapura Town

(Source: Environmental Atlas of Sri Lanka,

2005)

Average Maximum

NO2 0.13 ppm (1 hr) 0.005 ppm (1 hr) 0.01 ppm (1 hr)

SO2 0.08 ppm (1 hr) 0.003 ppm (1 hr) 0.012 ppm (1 hr)

CO 26 ppm (1 hr) 1 ppm (1 hr) 2.5 ppm (1 hr)

PM10

PM2.5

100 µg/m3 (Annual)

50 µg/m3 (Annual)

30 µg/m3 (1 hr)

Not measured

40 µg/m3 (1 hr)

Not measured

O3 0.10 (1 hr) Not measured Not measured

In view of the above observations it was evident that all air pollutant levels in Anuradhapura

are well below the permissible levels even though the road traffic especially heavy vehicle

movement has been reported to be moderately high within the City limits. Therefore, we can

safely extrapolate this observation and conclude that the air quality in the vicinity of the site

and surroundings are well-below the observations obtained for Anuradhapura and below

Maximum Permissible Levels.


23

2.2.8 Water Quality

The water quality of the tank seems to be not degraded significantly even with moderate

levels of anthropogenic activities that are found to be accruing in the surrounding of the

tank. However, slight turbidity issues were seen during the site visit, particularly in the area

of rip rap as the soil underneath was stirred up due to wind induced currents striking the rip

rap. This issue was very much localized and was not considered to be an adverse issue for

aquatic ecosystems. Nevertheless, it was mentioned by the villagers that during the windy

periods, there have been a substantial level of turbidity that could be found as the rip rap

was not properly placed in certain sections. In other words, soil particles beneath the rip rap

are washed off, causing turbidity plumes in the local areas resulting in smothering effects on

fauna. This scenario in the long run may tend to fail the rip rap completely in different

sections, hence neglecting corrective actions in the long run may create safety issues.

Other than the sporadic turbidity issues there have not been other water quality issues

reported in the tank.

2.3 Biological Environment with Flora and Fauna

2.3.1 Existing Habitats in the Project Affected Area

Biogeographically, the Angamuwa dam located within the low country dry zone. Floristically

it is under Dry and Arid Lowlands Floristic Zone and Tropical Dry Mixed Evergreen Forests

{Manilkara Community, Mixed community (Chloroxylon-Vitex-Berrya-Schleichera series)},

Tropical Thorn Forests (Manilkara-Chloroxylon-Salvadora-Randia series), Damana and Villu

Grasslands, Flood-plain Wetlands, Riverine and Gallery Forests are typical natural

vegetation formations in the Dry and Arid Lowlands Floristic Zone.

However, none of the above mentioned typical natural vegetation formations are not exists

in the dam area as the area is highly man modified. Dam and associate vegetations

(vegetations on the dam, vegetation associate with water logged or marshy lands in

downstream area, vegetation associate with rocky outcrop, cultivated lands and home

gardens in downstream area), tank and irrigation canals, vegetations in the tail canal are

major existing habitats / vegetations in the dam area. Secondary scrublands and seasonal

marshy vegetation can be observed in the proposed material (Gravel and Earth) obtain

area.

2.3.2 Existing Flora and Fauna in the Tank and Surrounding Habitats

2.3.2.1 Flora and Fauna in the Tank bund Area

Weedy, exotic and pioneer herbs, shrubs, climbers and trees, Chromolaena odorata

(Podisinnamaran), Cassia tora (Peti Tora), Vernonia cinerea (Monara Kudumbiya), Mimosa

pudica (Nidikumba), Flueggea leucopyrus (Heen Katu Pila), Sida acuta (Gas Bebila),

Xanthium indicum (Uru Kossa), Phyllanthus reticulatus (Kaila), Ocimum americanum (Heen

Tala), Tephrosia purpurea (Pila), Calotropis gigantea (Wara), Ricinus communis (Beheth

Endaru), Tribulus terrestris (Nerinchi), Bauhinia racemosa (Maila), Chloris barbata (Mayuru


24

Tana), Cardiospermum halicacabum (Wel Penela), Cassia occidentalis (Peni Tora),

Panicum maximum (Rata Tana), Sida cordifolia (Wal Bevila), Aerva lanata (Pol Pala), Hyptis

suaveolens (Madurutala), Hibiscus micranthus (Bebila), Crotalaria verrucosa (Nil Andana

Hiriya), Lantana camara (Gandapana), Leucaena leucocephala (Ipil Ipil), Hibiscus vitifolius

(Maha Epala), Azadirachta indica (Kohomba), Commelina sp., Boerhavia diffusa (Pita Sudu

Pala), Cleome viscosa, Dipteracanthus prostratus (Nil Puruk), Evolvulus alsinoides (Visnu

Kranti), Mikania cordata (Wathu Palu), Pergularia daemia (Medahangu), Tephrosia villosa

(Bu Pila), Rauvolfia tetraphylla, Abutilon hirtum (Wal Anoda), Achyranthes aspera (Gas

Karal Heba), Tridax procumbens, Passiflora foetida, Indigofera sp., Coccinia grandis

(Kowakka), Clitoria ternatea (Katarodu), Morinda coreia (Ahu), Ipomoea marginata (Rasa

Tel Kola), Lannea coromandelica (Hik), Gomphrena celosioides are common in the

vegetation on the dam.

Holoptelea integrifolia (Goda Kirilla), Schleichera oleosa (Koon), Azadirachta indica

(Kohomba), Tamarindus indica (Siyabala), Mitragyna parvifolia (Helamba), Syzygium cumini

(Madan), Ficus racemosa (Attikka), Ceiba pentandra (Pulun), Ficus benghalensis (Maha

Nuga), Bauhinia racemosa (Maila), Lannea coromandelica (Hik), Lepisanthes tetraphylla

(Dambu), Cordia dichotoma (Lolu) are common inhabiting trees and Ziziphus oenoplia

(Heen Eraminiya), Vernonia zeylanica (Pupula), Croton aromaticus (Wel Keppetiya),

Argyreia populifolia (Giritilla), Toddalia asiatica (Kudu Miris), Diospyros montana, Pongamia

pinnata (Magul Karanda), Ficus mollis (Wal Aralu), Strychnos nux-vomica (Godakaduru),

Strychnos potatorum (Ingini) are other inhabiting plant species in the vegetation on the dam.

Figure 2:9: Vegetation on the Dam

Persicaria attenuata (Sudu Kimbul Wenna), Typha angustifolia (Hambu Pan), Nymphaea

pubescens (Olu), Cyperus ssp, Fimbristylis ssp, Colocasia esculenta (Gahala), Alocasia

macrorrhizos (Habarala), Lasia spinosa (Kohila), Pandanus amaryllifolius (Rampa), Mikania

cordata (Wathu Palu), Eichhornia crassipes (Japan Jabara) are common plant species

associate with water logged or marshy lands in the downstream area.


25

Figure 2:10: Water logged or marshy lands in the downstream area of the tank bund

Sansevieria zeylanica (Niyanda), Bauhinia tomentosa (Kaha Petan), Ficus mollis (Wal

Aralu), Evolvulus alsinoides (Visnu Kranti), Flueggea leucopyrus (Heen Katu Pila),

Tephrosia purpurea (Pila), Ziziphus oenoplia (Heen Eraminiya), Morinda coreia (Ahu),

Azadirachta indica (Kohomba), Lannea coromandelica (Hik), Hibiscus micranthus (Bebila),

Pterospermum suberifolium (Welan), Hugonia mystax (Bu Getiya), Ventilago madraspatana

(Yakada Wel), Manilkara hexandra (Palu), Hyptis suaveolens (Madurutala), Chromolaena

odorata (Podisinnamaran), Lantana camara (Gandapana), Grewia orientalis (Wel Keliya),

Carissa spinarum (Heen Karamba), Benkara malabarica (Pudan), Aglaia elaeagnoidea,

Catunaregam spinosa (Kukurumanna), Derris scandens (Bo Kala Wel), Psilanthus

wightianus, Jatropha gossypiifolia, Hibiscus lobatus, Acacia pennata (Goda Hinguru),

Oxystelma esculentum (Usepale), Ehretia laevis, Reissantia indica, Mallotus repandus are

common inhabiting plant species in the rocky outcrop and associate vegetation

Figure 2:11: Rocky outcrop and associate vegetation

2.3.2.2 Flora and Fauna in the Tank and Irrigation Canals

Channa striata (Murrel), Etroplus suratensis (Pearl spot), Oreochromis niloticus (Tilapia),

Oreochromis mosambicus (Tilapia), Lepidocephalichthys thermalis (Common spiny loach),

Puntius bimaculatus (Redside barb), Rasbora microcephalus (Carverii Rasbora),


26

Heteropneustes fossilis (Stinging catfish), Dawkinsia singhala (Filamented Barb) are

commonly observed fish species in the tank and irrigation canals. Fish species, Dawkinsia

singhala (Filamented Barb) is endemic to the country.

Water and water associate bird species, Ardea cinerea (Grey Heron), Ardeola grayii (Indian

Pond Heron), Anhinga melanogaster (Oriental Darter), Ardea purpurea (Purple Heron),

Casmerodius albus (Great Egret), Egretta garzetta (Little Egret), Mesophoyx intermedia

(Intermediate Egret), Anastomus oscitans (Asian Openbill), Mycteria leucocephala (Painted

Stork), Phalacrocorax niger (Little Cormorant), Phalacrocorax fuscicollis (Indian Cormorant),

Amaurornis phoenicurus (White-breasted Waterhen), Threskiornis melanocephalus (Black-

headed Ibis), Vanellus indicus (Red-wattled Lapwing), Halcyon smyrnensis (White-throated

Kingfisher), Alcedo atthis (Common Kingfisher), Chlidonias hybrid (Whiskered Tern), Sterna

albifrons (Little Tern), Actitis hypoleucos (Common Sandpiper), Dragonflies, Pantala

flavescens (Wandering Glider), Crocothemis servilia (Oriental Scarlet), Copera marginipes

(Yellow Featherleg), Ceriagrion coromandelianum (Yellow Waxtail), Brachythmis

contaminata (Asian Groundling), Rhyothemis variegata (Varigated Flutter), Amphibians,

Euphlyctis cyanophlyctis (Skipper frog), Fejervarya shyadrensis (Common paddy field frog)

are common associate fauna species with tank and irrigation canals.

Figure 2:12: Tank and Irrigation canals


27

2.3.2.3 Rare, Threatened and Endemic Flora and Fauna in the Tank and

Surrounding Habitats

Vernonia zeylanica (Pupula), Argyreia populifolia (Giritilla) are recorded endemic plant

species and Strychnos nux-vomica (Godakaduru), Strychnos potatorum (Ingini) are

recorded nationally vulnerable (VU) plant species. Holoptelea integrifolia (Goda Kirilla),

Diospyros montana are recorded near threatened (NT) plant species.

Manilkara hexandra (Palu) and Psilanthus wightianus are recorded nationally vulnerable

(VU) plant species and Sansevieria zeylanica (Niyanda) is recorded near threatened (NT)

plant species in the rocky outcrop and associate vegetation.

Fish species, Dawkinsia singhala (Filamented Barb) was recorded in the irrigation canals

and streams of the project area and it is endemic to the country.

2.3.3 Ecological Signifcance of the Proposed Borrow Areas

2.3.3.1 Proposed borrow sites for obtaining gravel

Gravel for Angamuwa dam rehabilitation work to be obtained from nearby location and

secondary scrublands are the major existing vegetations/ habitats observed in and around

the proposed gravel obtain area. Dichrostachys cinerea (Andara), Flueggea leucopyrus

(Heen Katu Pila), Ocimum americanum (Heen Tala), Sida acuta (Gas Bebila), Hibiscus

micranthus (Bebila), Aerva lanata (Pol Pala), Ipomoea marginata (Rasa Tel Kola), Lantana

camara (Gandapana), Chromolaena odorata (Podisinnamaran), Tephrosia purpurea (Pila),

Cardiospermum halicacabum (Wel Penela), Hyptis suaveolens (Madurutala), Evolvulus

alsinoides (Visnu Kranti), Lannea coromandelica (Hik), Grewia helicterifolia (Bora

Daminiya), Cassia fistula (Ehela), Holoptelea integrifolia (Goda Kirilla), Ficus mollis (Wal

Aralu), Ziziphus oenoplia (Heen Eraminiya), Ventilago madraspatana (Yakada Wel), Grewia

orientalis (Wel Keliya), Carissa spinarum (Heen Karamba), Benkara malabarica (Pudan),

Catunaregam spinosa (Kukurumanna), Psilanthus wightianus, Acacia pennata (Goda

Hinguru), Vernonia zeylanica (Pupula), Strychnos potatorum (Ingini), Bauhinia tomentosa

(Kaha Petan), Ocimum gratissimum (Gas Tala), Cissus vitiginea, Premna latifolia, Dioscorea

tomentosa (Uyala), Diplocyclos palmatus (Pasengilla), Momordica charantia (Batu Karavila),

Ipomoea obscura (Tel Kola), Triumfetta pentandra (Epala), Coccinia grandis (Kowakka),

Tinospora cordifolia (Rasakinda), Tinospora sinensis (Bu Kinda), Drypetes sepiaria (Weera),

Allophylus cobbe (Kobbe), Cissus quadrangularis (Hirassa), Euphorbia antiquorum (Daluk),

Premna alstoni (Gal Kera), Ochna lanceolata (Bo Kera), Abrus precatorius (Olinda), Vitex

altissima (Milla), Curculigo orchioides (Heen Bin Tal) are observed common plant species in

the area.

Vernonia zeylanica (Pupula), Premna alstoni (Gal Kera) are recorded endemic plant species

and Psilanthus wightianus, Strychnos potatorum (Ingini), Tinospora cordifolia (Rasakinda)

are recorded nationally vulnerable (VU) plant species. Vitex altissima (Milla), Holoptelea

integrifolia (Goda Kirilla) are recorded nationally near threatened (NT) plant species. Plant

species, Lantana camara (Gandapana), Chromolaena odorata (Podisinnamaran) that


28

observed during the study within the proposed gravel obtain area are consider as alien

invasive plant species.

With respect to fauna, two endemic species, one bird, Gallus lafayetii (Sri Lanka Junglefowl)

and one butterfly, Appias galane (Lesser albatross) were recorded within the area.

Figure 2:13: Proposed gravel borrow area

2.3.3.2 Proposed borrow sites for obtaining earth

Earth for the Angamuwa dam rehabilitation work will be obtained from tank bed in the

periphery of the tank. The area is seasonally inundated and Eichhornia crassipes (Japan

Jabara), Actinoscirpus grossus, Nymphaea nouchali (Manel), Nymphaea pubescens (Olu),

Ottelia alismoides, Pistia stratiotes (Diya Paradel), Panicum repens (Etora), Ludwigia

adscendens (Beru Diyanilla), Ceratophyllum demersum, Persicaria attenuata (Sudu Kimbul

Wenna), Cyperus ssp, Fimbristylis ssp, Marsilea minuta are inhabiting aquatic and semi

aquatic plant species in the area. No endemic plant species observed and Nymphaea

nouchali (Manel) is inhabiting nationally vulnerable (VU) plant species.

Figure 2:14: Proposed borrow site for earth extraction


29

2.3.4 Migratory Paths

According to the information received from the villagers, there are no elephant paths

recorded in the area. However, the tank area is a preferable habitat for the migratory birds

which can be seen during the migratory season during October to April of every year.

2.4 Socioeconomic Environment

2.4.1 Local Administrative Units in the Project Area

The reservoir and its related other features are located in Rajanganaya Divisional

Secretariat of Anuradhapura District in North Central province. The specific details of the

local administrative units related to the project are mentioned below table 2.2:

Table 2.2: details of the local administrative units related to the project

Features of the irrigation

scheme

Relevant Grama

Niladhari divisions Relevant Villages

Head works and catchment area 448 Angamuwe Angamuwe Fishery Village

Command area

448-Angamuwe

449-Thumbullegama

450-Alivanguwe

451-Gamunupura

452-Track 9 and 10

453-Vijayapura

454-Track 12

455- Veheragala

456-Track 18

457-Adikaripura

458-Youth Farm

Angamuwe

Track 6 and 8

Thumbullegama

Akkara 50

Karuwalagaswewa

Lift irrigation area

Alivanguwe

Track 7

Siyambalagahagama

Gamunupura

Ingammaruwe

Temple Canal

Lunupitiya

Bogasela

Track 9 and 10

Track 11 and 12

Vijayapura

Banakoloniya

Veheragala

Track 13 and 14

Track 18 and 15

Adikaripura

Track 16 and 17

Namalsevanagama

Residential areas of farmers -do- -do-


30

2.4.2 Land Use in Different Areas of the Irrigation Schemes

2.4.2.1 Catchment Area

The catchment area of this tank has not been encroached for any economic activities. The

entire extent of the catchment area gets filled with water at the FSL level and it is about 350

Acres. There are no encroachments in the catchment area of the tank.

2.4.2.2 Downstream of the Dam

The downstream of the Dam can be divided in to 2 areas for the ease of describing the land

use. The right side of the downstream area falls from end of the bund up to flat stone on

middle of the bund. The left side starts from the stone and runs up to the end of the bund

(See Sketch attached). The land area below the Dam on right side which belongs to ID has

been demarcated and it has not been encroached for any purpose.

The land belt below the dam on left side from the spill has been encroached for some socio-

economic purposes. This land belt is about 1,000 m long and 9 persons have encroached it

for several purposes. They have grown 39 coconut trees, 45 Banana bushes and also

constructed 2 shallow wells, one toilet pit and one poultry farm (with 10x 20 feet extent). The

schematic diagram to show the land use of the immediate dowanstream area of the tank

and the details of the 9 encroachers are shown in Annex 2.

2.4.2.3 Command Area

The total command area of the reservoir is 6,181 acres distributed among 22 Farmer

organizations (FOs). About 5,194 acres of this total command area falls under gravity

irrigation systems and the balance 987 acres is fed under a lift irrigation system. The land

use pattern of the gravity irrigation system is as follows:

The plot size ranges from 2 acres to 2.5 acres of each farmer family

About 20% of the total area is grown with perennial and semi-perennial crops such

as Banana and coconut.

The 80% of the command area is cultivated with 100% paddy in Maha seasons.

In Yala seasons about 75% of the area is grown with paddy and the balance is

with other seasonal field crops (OFCs)

Each farmer family in lift irrigation system has about 2 to 2.5 acre plot. Each plot has been

grown with perennial and semi-perennial crops such as coconut and Banana. Further details

of the land use pattern existing in gravity and lift irrigation systems are shown in the Annex

3.

2.4.3 Demographic Data Relevant to the Project Area

The population in the 11 GN areas of Rajanganaya DSDs is defined as project relevant

community. The community members in these 11 GN divisions have established 22 Farmer

Organizations (FOs). Some of the families in these 11 GN divisions are land owners under

the tank command and therefore, they are members of the 22 FOs. Nearly 50% of total


31

families in these GN divisions do not have land under Angamuwe irrigation scheme. The

99% populations residing in 11 GN areas are Sinhala ( except few Muslim families). The

details of population relevant to the proposed project are mentioned in Table 2.3.

Table 2.3: Details of Project Relevant Population

FO

GN

Total

Famili

es

Land owners Landless

No of

families Population

No of

families Population

Arunnalu –

Track 6

448 Angamuwe

449

Thumbullegama

433 84

912 550 1784 Track 6 BOP

Dimuthu 402 81

Track 7 BOP

Purasanda 120

Track 7 BOP

Suhada

450 Alivanguwe

451 Gamunupura

421 59

1452 574 2010

Track 7

Jayasri 568 92

Track 8

Mahasen 149

Track 8 BOP

Navajaya 115

Track 9

Nethsiri

452 Track 9,10

453 Vijayapura

518 180

2270 305 1218

Track 9 BOP

Pubudu 356 41

Track 10-

Ruhunu 98

Track 11

Ranketha 250

Track 12

Predeepalok

a 454 Track 12

455 Veheragala

438 179

2167 631 2261

Track 13 798 161


32

Ekamuthu

Track 13

Pregathi 72

Track 14-

Vijaya 193

Track 15-

Jayamaha

457 Adikaripura

720 217

2630 54 214

Track 15

BOP

Ekamuthu

360

Track 15

BOP Udara 89

Track 15-

BOP Track

11, 15 456 Track 18

438 122

962 165 582

Track 18 Sri

Vijaya 151

Track 16

Youth Farm

458 Youth Farm

930 268

2260 342 1316

Track 17

Saraketha 320

Total 6022 3401 12653 2621 9385

The population of 9 families captured downstream reservation of the tank bund is 35. Only 5

families out of 9 are residing in the encroached land. The details of these families are given

in Annex 2.

2.4.4 Economic Activities of Project Related Population

The distribution of income generation activities among families in the project related 11 GN

divisions is given in Table 2.4.


33

Table 2.4: Distribution of Income Generation Activities among Families in Project

Related Villages

Economic Activity Percentage of Families

Farming 55

Government employment 15

Private sector employment 20

Others (fishery, small business & foreign employment) 10

Source: FO leaders, GNs

The employments of the 9 families belong to encroached land of downstream of the dam

includes

Agriculture – 4 families

Growing ornamental flowers- 1family

Private sector- 1 family

Self employments- 2 families

Labor- 1 family

The details of the employments and the family size of the 9 families are given in Annex 2.

2.4.4.1 Yield and Income from Agriculture

a). Yield and Income from Agriculture

Paddy farming is the main source of income of the project relevant families in Angamuwa

irrigation scheme. According to the leaders of the farmer organizations and the 12 general

farmers interviewed (Annex 1) yield of the farmers in the scheme are fairly homogeneous.

Therefore, the information related to one farmer on yield and income of an acre cultivated

with paddy is mentioned below as representative case of the Padaviya irrigation scheme.

Yield – 2,442 kg per acre per season

Selling price and the gross income – 2,442kg * Rs 35/- = Rs 85,470/-

Average expenditure – Rs. 46,450/-

Net income – Rs 38,820/- per season ( Rs. 85,470 – Rs.46,450 )

Further details of the calculation of cost benefit are shown in Annex 4.

b). Cost Benefit Analysis of the Yield and Income from the entire irrigation

scheme

The team further worked out the cost benefit of the entire Angamuwa irrigation scheme

(Gravity Irrigation System) with the experience of the leaders of farmer organizations. The


34

details expressed by the farmer leaders are shown below table 2.5:

Table 2.5: Details Expressed by the Farmer Leaders

Yield Gross income Rs. Expenditure items Expenditure Rs.

Total land area =

5,194 acres, Yield of

an acre = 2,442 Kg ,

Total Yield = 2,442 *

5,194= 12,683,748

Kg

4,439,311,080

(12,683,748 kg * Rs.

35/-)

Total land area 5,194

acres, expenditure of

1 acre per season

Rs. 46,650/-,

Total expenditure of

the entire scheme

242,300,100 (5,194 *

46,650)

Note:

Total gross income – Rs. 4,439,311,080/=

Total expenditure – Rs. 242,300,100 /-

Net income – Rs 201,631,080/-

2.4.5 Other Water Uses

Three other direct and indirect water uses are reported in Angamuwa irrigation scheme

area. The details of these water uses are described below:

2.4.5.1 Fishing Activities

Fishing is a significant economic activity taking place in Angamuwe tank. The fishermen

have formed a separate organization and has registered it as a cooperative named

"Angamuwe Inland fishery cooperative Society". There are about 200 persons who have

registered as members in this Community-based Organization (CBO). They operate their

fishing activities from 4 boat landing sites and the members of the cooperative have 77

fishing boats. A fisherman is able to catch a quantity worth about Rs 1000 to 1,500/day. The

fish buyers from other areas around Rajanganaya/Tambuttegama visit to buy fish from

fishermen to sell in other villages in the area. The distribution of fishing boats among 4 boat

landing sites is shown below:

Angamuwe landing site - 30 boats

Navasirigama landing site - 30 Boats

Sirimapura ( Horombagama) Landing site – 12 Boats

5th Mile post Landing site - 5 boats

2.4.5.2 Bathing and Washing

There are about 150-200 families residing in Angamuwe Fishery village and Track 6 colony

used to go for bathing and washing in the reservoir


35

2.4.5.3 Small Industries

About 21 rice mills are available in the project area and their performance is completely

depended on the agriculture in Angamuwa Irrigation system (6 large scale mills and 15

minor scale mills). Another about 10 mills use for rice processing and grain milling are also

available.

2.5 Current Environmental Issues of the Project Area

This subsection discusses the other issues pertaining to the area other than those that

would be caused by the project activities. The project activities may trigger some of them,

resulting in adverse impacts. Hence it is of paramount importance to mention such issues in

brief in order to lessen such impacts, if envisaged.

2.5.1 Physical Issues

There is no any major physical issue recorded in the project area.

2.5.2 Ecological Issues

There is no any major ecological issue recorded in the project area.

2.5.3 Socioeconomic Issues

The majority of the population in the project area can be defined as agriculture community of

which livelihood activities are heavily dependent on irrigation water and crop cultivation.

Therefore, most of the community members who were consulted expressed several issues

related to water and agriculture. The issues they expressed are summarized below:

Rapid fragmentation of land (both residential and irrigated). This has resulted in the

second and third generation families attempting to make their residences in the

irrigated lands plots

The cost of production under lift irrigation system is increasing rapidly

The fish fingerlings have not been provided for about 10 years and therefore, fish

population in the reservoir is very low at present

The small tanks located along the main canals are congested with water weeds

creating water management problems in main system (e.g. Thummulla tank,

Phalamaragahawewa).

Tendency of Farmers of Mahaweli System H located in the upstream of Angamuwa

Reservoir to expand their irrigated land towards the catchment area of Angamuwa.


36

3. CHAPTER 03 : PROPOSED INTERVENTIONS

3.1 Proposed Engineering Interventions

The structural and operational issues of the dam, which are identified and observed during

the initial site visit are summarized in Table 3.1 and the photographic evidences for the

identified issues are given in Figure 3.1.

Table 3.1: Current issues in Angamuwa Tank Bund

a. Issues identified as per the ToR

Issue Intervention Construction methodology

1. Washed away

U/S slope and

rip rap

collapsed in

some areas

(Figure 3.1 A)

Improvements to tank

bund U/S slope and

bund crest (0+000 m to

1+775 m)

Removing the existing riprap and placed in

stockpiles in D/S identified areas for re-

measurement and re-use

Stripping topsoil to a depth of 100 mm

Benching along the tank bund slope by

machinery and backfilling including watering and

compaction

Furnishing, placing, spreading, watering and

compacting of gravel as wearing layer for dam

crest road and rip rap base.

Furnishing and placing a Geo textile along the

slope as directed

Furnishing and placing new graded rip rap as

directed

Turfing

2. Seepage areas

along the D/S

toes (Figure

3.1B)

Slope stabilization

and seepage control

Clearing and grubbing vegetation

Felling, logging uprooting trees on U/S and D/S

Reinstating cavities as directed

Removal of ant hills on D/S

Backfilling using suitable burrow material with

watering and compaction

Construction of toe drain and toe filter 0+150 m

to 0+200 m

3. Water

stagnating at

the dam

(Figure 3.1C)

Construction of pond

in D/S of tank bund

to collect toe drain

water at 0+067 m

and 0+310 m

Clearing and Grubbing of weeds

Stripping topsoil to remove loose soil

Borrow earth from identified borrow areas and

forming around the pond including watering and

compacting using manual labour

Furnishing and compacting rubble for U/S slope

of pond

Construction of spillway for proposed pond

Preparing and installation of measuring gauge


37

for measuring pond water

4. Encroachments

at the dam

(Figure 3.1D)

Consult the

unauthorized settlers

and explain the need

of having a toe road

for the inspection

and safety of the

dam

Clear out the tank

reservation

Consultation process with all stakeholders

Formulation of action plan for relocation as per

law of the country

b. Issues identified during the initial site visit

Issue Intervention Construction methodology

5. The bund road

is with lots of

pot holes and

eroded places

(Figure 3.1F)

Construction of

access road from

0+000 m to 1+775

m

Construction of a

vehicle turning point

at the end of bund

road

Clearing and grubbing of weeds

Trimming and levelling the top surface of the

bund road by machinery

Furnishing, placing and compacting of the gravel

layer on the surface, including watering and

compacting by machinery

6. Structural

failures of the

spillway such as

failure of

abutments,

sliding of

sections (Figure

3.1G)

Construction of

curtain wall at U/S of

spill

Construction of coffer dam as required

Fixing dowels to existing rock surface as

directed

Fixing tor steel reinforcement net as directed

Placing and compacting cement concrete as

directed

7. Malfunction of

spillway radial

gates

Repairing radial

gates by removing

corroded parts of the

gates

Replace seals and

cables and related

attachments

Provision of motor

driven arrangements

for operation

In-situ repairs carried out for the gates –

removal of parts and replacing

Installation of motor driven system for the radial

gates

8. Leakage

through right

wing wall of

sluice and

Repairs in D/S of

sluice

Construction of

Gabion wall for slope

protection

Excavation for construction of gabion walls

Construction of gabion boxes

Transportation of rubble for gabions


38

suspected areas

in U/S (Figure

3.1H)

Providing emergency

gates

Placement gabions and backfilling as needed

9. No bathing

steps and

inspection steps

Construction of

bathing steps at

0+100m,

0+500m,1+450 m,

and inspection steps

at 1+325 m of tank

bund

Displacement of rip rap as required

Construction of bathing steps and inspection

steps

Rearranging the rip rap as needed

10. Lack of security

facilities

Construction of

watcher hut and

storage area for the

field equipments at

the left end of

spillway

Site clearance

Material transportation for construction of the hut;

material storage

Construction of the hut

11. Anchoring

boats along the

U/S slope of

dam cause

bund erosion

and scouring

(Figure 3.1I)

Construction of boat

yard in Angamuwa

tank at 1+500 m of

tank bund

Transportation of material for the construction of

the boat yard

Removal of rip rap as required for construction of

the boat yard

Construction of boat yard

Rearrangement of the riprap and filling the bund

as needed

Figure 3:1.1A: Washed away U/S slope and rip rap collapsed in some areas


39

Figure 3:2 B: Seepage areas along the

D/S toes

Figure 3:3 C: Water stagnating at the dam

Figure 3:4 D: Encroachments at the dam Figure 3:5 F: The bund road is with lots of

pot holes and eroded places

Figure 3:6 G: Structural failures of the

spillway such as failure of abutments,

Figure 3:7 H: Leakage through right wing

wall of sluice and suspected areas in U/S


40

sliding of sections

Figure 3:8 I: Anchoring boats along the U/S

slope of dam cause bund erosion and

scouring

3.2 Proposed Borrowing Activities and the Identified Borrow Sites

The details of the borrow sites identified for the rehabilitation of Angamuwa tank are

described briefly in Error! Reference source not found. below.

Table 3.2: Location Details of the Identified Borrow Sites

Burrow Material Description GPS Location

Quarry site

The quarry site owned by N.S.K

Construction (Mr A.M.T. Adhikari) in

Singharagama Village within a Mahaweli

Land.

It is a “B” grade quarry site with GSMB and

CEA licenses

08o 16.431

080o 15.178

Gravel & Earth The site is located in the tank bed closer to

the bund and the area is inundated

08o 10.071

080o 13.500

Gravel Site 2 Existing site 08o 10.938

80o 12.809

Earth Site 2

The earth site is located in the tank bed

closer to the bund and the area is

inundated

08o 09.991

80o 13.474

The location maps for the identified borrow sites are given in the Annex 6a and 6b.


41

3.3 Proposed Interventions that could Affect Neighboring Communities

Almost all the interventions will affect the neighboring communities in some manner;

however, they are not significant. The following interventions among what have been

proposed can be listed as interventions that could affect neighboring communities:

Material transport, stockpiling especially for graveling the bund road, rip rap

construction, correcting the slopes of the bund etc.

Providing toe filters, toe drain and the toe road along the toe area of the bund

Rehabilitating the bund (including construction of the rip rap) will prevent access to

the tank

3.4 Proposed Interventions that could affect the Natural Habitats

There is no significant impact anticipated, however removal of weedy shrubs and grasses

will disturb the associated faunal groups those who use such habitats as feeding, breeding

or nesting areas. Since there are enough similar habitats in the surrounding area, there will

be no or minor impact to such species.

The noise and dust created as a result of increase of vehicular traffic and heavy machinery

operations would temporary affect the existing fauna specially the avifauna.

The proposed rehabilitation work will take place within the Padaviya Sanctuary area and the

noise, vibration and hindrance to access paths will create a temporary disturbance to the

existing wild life in the area.


42

4. CHAPTER 04 : PROJECT INDUCED IMPACTS

4.1 Identification of Project Induced Impacts

Note: The anticipated impacts described under this section are mainly for the construction

phase only. However, any impacts that are induced during operational stages (if any) are

also presented where applicable. The impacts are confined to negative impacts, as the

positive impacts as a result of improved dam safety and improved operational capacities of

Headworks are obvious and perceived.

Impacts were classified into three categories:

No: Environmental effects are perceived to have been no change at all.

Low: Environmental effects are not detectable or are so minor that they will neither

destabilize nor noticeably alter any important attribute of the resource.

Moderate: Environmental effects are sufficient to noticeably alter important

attributes of the resource, but not to destabilize them.

High: Environmental effects are clearly noticeable and are sufficient to destabilize

the resource.

Table 4.1 depicts the possible impacts together with their significance on each intervention

proposed.


43

Table 4.1: Possible Impacts due to the Proposed Interventions and their Significance

Issues identified as per the ToR

Issue Intervention Anticipated Impacts Significance

1. Washed away

U/S slope and

rip rap

collapsed in

some areas

(Figure 3.1 A)


bund U/S slope and

bund crest (0+000 m

to 1+775 m)

Impact on Ecological Environment:

i. Damage to terrestrial and aquatic habitat

Clearing weedy shrubs, grasses and trimming the branches of the trees would

create habitat loss for the faunal species that use such habitats as their

feeding, breeding and nesting grounds. However, since there are enough

similar habitats available in the surrounding area, such species will get adapted

to the new conditions and hence the impact will be very low or none.

Low

ii. Threat of spreading of invasive species

The material to be extracted from the tank bed which is inundated during the

most of the time of the year. So there is a very less possibility of spreading

such species during material extraction.

Low

iii. Effect on fauna

There can be insignificant levels of noise and dust produced during material

transportation and construction work. In addition, due to heavy machinery there

may be temporary disturbances to the animals (especially migratory birds)

inhabiting the tank area.

However, the quantity of work will be less and hence the impact will be low.

Low


44

Impact on Social Environment

i. Impact due to Material Transportation

Transportation routes of the borrow material (earth and Gravel) not associated

with the residential area and hence impact will be low or none

Low

ii. Impact due to lowering the water level in the tank

No negative impacts on the farming community if the work is carried out during

the dry season when the water level is lowest. Repair and rehabilitation work

will be undertaken only in Yala season.

No

Impacts on Physical Environment:

i. Hindrance to surface runoff

Borrow material once brought to the site has to be unloaded and stockpiled for

subsequent use. This might block the existing run – on and off paths which

may create erosion problems elsewhere.

However the quantity to be handled seems to be small, hence the impact may

not be significant.

Low

ii. Raw water quality of surface water bodies

Runoff through material borrow areas and unloading sites could lead to wash

off of soil particles to nearby water bodies such as canals, tanks streams etc.

resulting in temporary turbidity problems. However, the quantity to be handled

seems to be very low, hence adverse impacts anticipated would be

insignificant.

Low


45

iii. Increasing the possibilities of erosion of the U/S/and D/S slopes

Exposed areas of the bund are susceptible to erosion. Low

iv. Increase in vehicular traffic during transport of construction materials

Material transport may result in air pollution through giving rise to elevated

levels of airborne dust. There are dwelling units along haulage routes and

elevated levels of airborne particulate matter can become a minor temporary

adverse impact during the construction period.

Low

v. Health and sanitation of worker’s camps and that of residents in the

adjoining areas

This impact is common for all the activities. The temporary camps, if not

managed properly, may create an unhealthy environment causing health

hazards to both workers and nearby residents. However, the number of

workers to be employed

Low

seems not many. Hence the impact is insignificant.

vi. Management of construction waste and excavated material and

wastewater

No significant quantities of construction waste are expected. In contrast, food

items even in small quantities may attract stray animals. However, the overall

impact is very low.

Low

vii. Generation of noise, vibration and dust affecting the social and

biological environment

Noise and vibration is very low due to the small-scale nature of construction

activities. Activities that would produce airborne dust are temporary and limited

Low


46

to short durations and will be restricted to a small area.

viii. Impact of low water levels in the reservoirs during repairs

This impact could be very significant if the water levels are lowered suddenly.

However, the construction is planned to be carried out particularly during Yala

season where water level is expected to be lower compared to other seasons.

Low

2. Seepage areas

along the D/S

toes (Figure

3.1B)

Slope stabilization

and seepage

control


i. Damage to aquatic habitat

Sediments, oil & grease and other chemicals that can be mixed into tank water

can pollute the aquatic habitat and will affect the fish and other aquatic faunal

species.

Low

Impact on Social Environment:

No negative impacts are envisaged on the farming community if the work is

carried out during the dry season.

No



The borrow material once brought to the site has to be unloaded and stockpiled

for subsequent use. This might block the existing run–on and off paths which


However, the quantity to be handled seems to be small, hence the impact may

not be significant.

Low



Low


47




insignificant.

iii. Increase in vehicular traffic during transport of construction materials





Low

iv. Health and sanitation of worker’s camps and that of residents in the

adjoining areas




workers to be employed seems not many. Hence the impact is insignificant.

Low

v. Management of construction waste and excavated material and

wastewater



impact is very low.

Low

vi. Generation of noise, vibration and dust affecting the social and





Low


48

3. Water

stagnating at

the dam

(Figure 3.1C)

Construction of

pond in D/S of tank

bund to collect toe

drain water at

0+067 m and

0+310 m


Positive impact on ecological environment as it will create better habitats for the

surrounding fauna.


No negative impacts are envisaged No



4. Encroachments

at the dam

(Figure 3.1D)

Consult the

unauthorized

settlers and

explain the need of

having a toe road

for the inspection

and safety of the

dam

Clear out the tank

reservation


No significant ecological impacts during construction is envisaged

Impact on SocialEnvironment:

No impact on the economic activities of the people as they have their own main

income sources and lands other than the encroached portion

No



c. Issues identified during the initial site visit

Issue Intervention Anticipated Impacts

5. The bund road

is with lots of

Construction of

access road from Impact on Ecological Environment:


Low


49

pot holes and

eroded places

(Figure 3.1F)

0+000 m to 1+775

m

Construction of a

vehicle turning

point at the end of

bund road

Clearing weedy shrubs, grasses and trimming the branches of the trees

would create habitat loss for the faunal species that use such habitats as

their feeding, breeding and nesting grounds. However, since there are

enough similar habitats available in the surrounding area, such species will

get adapted to the new conditions and hence the impact will be very low or

none.


The material to be extracted from the tank bed which is inundated during the

most of the time of the year. So there is a very less possibility of spreading

such species during material extraction.

Low

iv. Effect on fauna

There can be insignificant levels of noise and dust produced during material

transportation and construction work. In addition, due to heavy machinery there

may be temporary disturbances to the animals (especially migratory birds)


However, the quantity of work will be less and hence the impact will be low.

Low

ii. Effect on aquatic habitat



species.

Low



Transportation routes of the borrow material (earth and Gravel) not associated

with the residential area and hence impact will be low or none

Low

ii. Impact due to blockage of access


50

The bund road is not used as an access to residence or it is not linked with

other settlement. However, there will be a temporary disturbance to the people

those who access tank for their domestic purposes.



Borrow material once brought to the site has to be unloaded and stockpiled for

subsequent use. This might block the existing run – on and off paths which


However the quantity to be handled seems to be small, hence the impact may

not be significant.

Low






insignificant.

Low

iii. Increasing the possibilities of erosion of the U/S/and D/S slopes

Exposed areas of the bund are susceptible to erosion. Low

iv. Increase in vehicular traffic during transport of construction materials





Low


51

v. Health and sanitation of worker’s camps and that of residents in the

adjoining areas




workers to be employed seems not many. Hence the impact is insignificant.

Low

vi. Management of construction waste and excavated material and

wastewater



impact is very low.

Low

vii. Generation of noise, vibration and dust affecting the social and





Low

6. Structural

failures of the

spillway such as

failure of

abutments,

sliding of

sections (Figure

3.1G)

Construction of

curtain wall at U/S

of spill


No significant ecological impact during the construction No


No significant negative impacts during the construction are envisaged as the

construction will be carried out during dry season and using coffer damning

No

Impact on Physical Environment:

Increasing the possibilities of erosion of U/S/and D/S slopes

Low


52

Excavated and exposed areas of the bund are susceptible to erosion

In addition to those, general impacts such as generation of construction waste,

excavated material, wastewater, generation of noise and vibration and dust

which affect the social and biological environment could be envisaged. Since

the amount of work that has to be carried out is small, the impact is insignificant

7. Malfunction of

spillway radial

gates

Repairing radial

gates by removing

corroded parts of

the gates

Replace seals and

cables and related

attachments

Provision of motor

driven

arrangements for

operation


No significant ecological impact during the construction No


No significant negative impacts during the construction are envisaged.

No




In addition to those, general impacts such as generation of construction waste,

excavated material, wastewater, generation of noise and vibration and dust

which affect the social and biological environment could be envisaged. Since

the amount of work that has to be carried out is small, the impact is insignificant

Low

8. Leakage

through right

wing wall of

sluice and

suspected areas

in U/S (Figure

Repairs in D/S of

sluice

Construction of

Gabion wall for

slope protection

Providing



No



No


53

3.1H) emergency gates Impact on Physical Environment:

No significant impacts during the construction are envisaged No

9. No bathing

steps and

inspection steps

Construction of

bathing steps at

0+100m,

0+500m,1+450 m,

and inspection

steps at 1+325 m

of tank bund



No



No


No significant impacts during the construction are envisaged. However, general

impacts such as generation of construction waste, excavated material,

wastewater, generation of noise and vibration and dust which affect the social

and biological environment could be envisaged. Since the amount of work that

has to be carried out is small, the impact is insignificant.

Low


facilities

Construction of

watcher hut and

storage area for

the field

equipments at the

left end of spillway



No



No


No significant impacts during the construction are envisaged. However, general

impacts such as generation of construction waste, excavated material,

wastewater, generation of noise and vibration and dust which affect the social

and biological environment could be envisaged. Since the amount of work that

Low


54


11. Anchoring

boats along the

U/S slope of

dam cause

bund erosion

and scouring

(Figure 3.1I)

Construction of

boat yard in

Angamuwa tank at

1+500 m of tank

bund


i. Effect on aquatic habitat



species.

Low


There can be temporary impact to the fishermen, but there are enough of other

areas to carry out their activities and hence the impact will be low/none

No




Low


55

4.2 Quantification of their Significance

Determining the significance of impacts places value on impact magnitude. It relates to the

importance society places on the resources affected, the importance of the impact to system

stability and sustainability.

Quantification of impact magnitude in this study has been objective-based backed by prior

experience of the team of consultants, rather than applying numerical and/or scientific

principles and theories. Once the impact magnitude was determined based on the proposed

construction methodology for each intervention, each expert has decided on the significance

of the impacts based on their area of expertise. Significant impacts will be the focus of

mitigation measures and subsequent monitoring, as outlined in the report.

Factors that have been considered in determining of impact significance include

(but are not limited to):

Area of Influence: Impact significance is often directly related to the size of the area

affected.

Amount of Resource Usage: The greater the amount of resource usage, the more

significant the impact.

Status of Resources: Impacts due to usage of limited resources are usually

considered more significant than impacts to common or abundant resources.

Persistence of Impacts: Permanent or long-term changes are usually more

significant than temporary ones. The ability of the resource to recover, after the

activities are complete, is related to this effect.

Sensitivity of Resources: Impacts to sensitive resources are usually more

significant than impacts to those that are relatively resilient to impacts.

Regulatory Status: Impacts to resources that are protected (e.g., endangered

species, air quality, cultural resources, water quality) typically are considered more

significant than impacts to those without regulatory status.

Societal Value: Some resources have societal value, such as archaeological,

cultural and sacred sites, traditional practices, and recreational areas.

Hence, quantification of impacts was done based on the above-mentioned criteria

only for the impacts that are perceived to be either moderate or high.

All the impacts identified for the proposed interventions are either low or none and hence the

quantification of such impacts are not required for Angamuwa Dam rehabilitation work.

Environmental Assessment for Rehabilitation of Padaviya Tank Draft Final Report

56

5. CHAPTER 05 : ENVIRONMENTAL MANAGEMENT PLAN

5.1 General Overview

The purpose of this Environmental Management Plan (EMP) is to manage the anticipated

on and off-site environmental impacts due to the interventions proposed to remedy identified

issues of the dam. Therefore, it is necessary to first scan the issues that have arisen to

compromise the safety and operational efficiency of the Angamuwa Dam. The following

issues and their mitigation measures were identified and presented in the EMP.

5.2 Identification of Impacts and their Mitigations

This section summarizes the mitigation measures to be implemented for the identified

environmental impacts that can potentially occur predominantly during the construction

phase of the proposed interventions (Table 5.1). This table indicates only the ones that need

mitigation measures and those that are not listed would not require any mitigation

measures.

The DSWRPP has a strong focus on proper environmental management. Therefore, the

focus of environmental management of the project has not been limited to managing those

impacts arising due to the proposed interventions but also to improve adverse

environmental conditions that will prevail during rehabilitation work by applying proper

mitigation strategies.

As a part of the EMP, appropriate institutional arrangements to implement the proposed

measures and clearances and/or approvals needed by the project prior to its implementation

have been proposed after discussing with the responsible authorities 9Table 5.2). For each

proposed intervention, the EMP defines the technical content, roles and responsibilities of

stakeholders, schedule of implementation and methods of monitoring etc.


57

Table 5.1: Proposed Mitigatory Measures for the Identified Impacts

Issues identified as per the ToR

Issue Intervention Anticipated Impacts Proposed Mitigation

1. Washed away

U/S slope and

rip rap

collapsed in

some areas

(Figure 3.1 A)


bund U/S slope and

bund crest (0+000 m

to 1+775 m)



Clearing weedy shrubs, grasses and trimming the branches

of the trees would create habitat loss for the faunal species

that use such habitats as their feeding, breeding and nesting

grounds. However, since there are enough similar habitats

available in the surrounding area, such species will get

adapted to the new conditions and hence the impact will be

very low or none.

The easily decomposable

vegetation could either be

utilized as a soil conditioner

after drying or be composted in

a proper manner. Large

vegetation parts could be sold

or else be used as firewood.

The contractor is responsible

for proper management of all

vegetative parts that are to be

uprooted.

The project area must be

covered or fenced properly to

avoid disturbances to the

surrounding habitats including

the tank water


The material to be extracted from the tank bed which is

inundated during the most of the time of the year. So there is a

very less possibility of spreading such species during material

extraction.

Close monitoring of

transportation, storage of

borrowing material for the

spread of any invasive species

must be done. Vehicles should

be covered during


58

transportation.

Borrow material to be brought

from properly identified borrow

pits and quarry sites with

proper licenses

Washing the vehicles

periodically to prevent carrying

any invasive species

All the gravel transporting

vehicles must be covered

during transportation. Frequent

checks for invasive species

must be undertaken

iii. Effect on fauna

There can be insignificant levels of noise and dust produced

during material transportation and construction work. In

addition, due to heavy machinery there may be temporary

disturbances to the animals (especially migratory birds)


However, the quantity of work will be less and hence the impact

will be low.

The construction area of the

tank should be temporary

barricaded to restrict the

movement of animals into the

construction area.

The other habitat areas in the

vicinity of the tank should not

be disturbed so that fauna

inhabiting the area will move to

such areas.



Transportation routes of the borrow material (earth and Gravel)

The required mitigation is

mentioned below (see Impact

on Physical environment).


59

not associated with the residential area and hence impact will

be low or none

ii. Impact due to lowering the water level in the tank

No negative impacts on the farming community if the work is

carried out during the dry season when the water level is

lowest. Repair and rehabilitation work will be undertaken only in

Yala season.

No mitigation is required



Borrow material once brought to the site has to be unloaded

and stockpiled for subsequent use. This might block the

existing run – on and off paths which may create erosion

problems elsewhere.

However the quantity to be handled seems to be small, hence

the impact may not be significant.

Surface run on and off paths

should not be selected for

material unloading areas.

Erosion of material heaps can

be minimized by covering

them during rainy seasons.

Avoid stockpiling of materials

close to water bodies; Stripped

materials should not be stored

where natural drainage will be

disrupted. There are several

areas identified, especially the

eastern part of the bund

(downstream side) as suitable

for stockpiling and for

machinery, tools and vehicular

parking spaces. Use of these

areas for such purposes might

not pose negative impacts on


60

residential and cultivated areas

and also to the water body.


Runoff through material borrow areas and unloading sites could

lead to wash off of soil particles to nearby water bodies such as

canals, tanks streams etc. resulting in temporary turbidity

problems. However, the quantity to be handled seems to be

very low, hence adverse impacts anticipated would be

insignificant.

Surface run on and off paths

should not be selected for

material unloading areas.

Erosion of material heaps can

be minimized by covering

them during rainy seasons.

Avoid stockpiling of materials

close to water bodies; Stripped

materials should not be stored

where natural drainage will be

disrupted. There are several

areas identified, especially the

eastern part of the bund

(downstream side) as suitable

for stockpiling and for

machinery, tools and vehicular

parking spaces. Use of these

areas for such purposes might

not pose negative impacts on

residential and cultivated areas

and also to the water body.

iii. Increasing the possibilities of erosion of the U/S/and

D/S slopes

Exposed areas of the bund

slopes will be covered with


61

Exposed areas of the bund are susceptible to erosion. turfing material as soon as

possible to prevent any

erosion.

All the measures mentioned

above are valid for this impact

as well.

iv. Increase in vehicular traffic during transport of

construction materials

Material transport may result in air pollution through giving rise

to elevated levels of airborne dust. There are dwelling units

along haulage routes and elevated levels of airborne particulate

matter can become a minor temporary adverse impact during

the construction period.

Restrictions on the

transportation activities:

a. Maximum axial loads

and speed limits for

vehicles moving on the

bund will be imposed

b. Time limits for carrying

out transportation

activities to control

excessive noise

generation and to

prevent nuisance to

neighbouring

communities (6.00 am –

6.00 pm)

Dust emission due to transport

operations should be

controlled by wet spraying and

tarpaulin covering in

mandatory on trucks/lorries

which are used for transporting

materials particularly in built up


62

areas.

Transport, loading and

unloading of materials should

be carried out in such a way as

not to cause nuisance to the

people by way of noise,

vibration of dust. Care must be

taken while unloading material

on the bund so as the material

may be not rolled down on

either side of U/S and D/S

slopes causing damages

v. Health and sanitation of worker’s camps and that of

residents in the adjoining areas

This impact is common for all the activities. The temporary

camps, if not managed properly, may create an unhealthy

environment causing health hazards to both workers and

nearby residents. However, the number of workers to be

employed seems not many. Hence the impact is insignificant.

Conditions of worker camps to

be checked by the Public

Health Officer in charge of the

relevant area on a regular

basis.

All food leftovers and organic

garbage should be disposed of

in a proper manner so that it

will not attract stray and wild

animals. Solid waste should

not be burnt in the open air

within or outside the proposed

site.

Proper sanitation facilities

should be provided on-site for

the workforce. Ideally, this can


63

be a pit latrine in which the pit

is located above the ground

water table. Covering the

deposit (with earth or sawdust)

is necessary to prevent smells

and to discourage flies.

This measure is common for

all the interventions and

therefore applicable for the

whole project period.

vi. Management of construction waste and excavated

material and wastewater

No significant quantities of construction waste are expected. In

contrast, food items even in small quantities may attract stray

animals. However, the overall impact is very low.

Construction waste shall be

collected regularly and

disposed of periodically in an

environmentally safe and

nuisance free manner.

Wastewater will be disposed,

by way of a pit latrine/soakage

arrangement. This measure

too will be common and valid

for the entire construction

period.

vii. Generation of noise, vibration and dust affecting the

social and biological environment

Noise and vibration is very low due to the small-scale nature of

construction activities. Activities that would produce airborne

dust are temporary and limited to short durations and will be

restricted to a small area.

Hydraulically driven machinery

is preferred over Pneumatic

machinery to minimize

vibrations

No high noise generating

machinery is encouraged.

Extreme precautions need to


64

be taken on vibration levels as

it could affect the core of the

bund. Watering may be

necessary if any activity

generates dust particles.

Excessive noise and vibration

at the quarry site has to be

controlled. Implement the

conditions such as noise

monitoring and other

recommendations stipulated in

the permit; Obtain approval

from the Local Authority and

Divisional Secretary and

Controller of Explosives (for

quarry sites only) and CEA.

All raw materials (sand,

rubble, metal, etc.) should be

stored in covered areas to

ensure protection from dust

emissions and such materials

should be handled in an

environmentally friendly and

nuisance free manner.

These measures will also be

the same for all other

interventions.


65

viii. Impact of low water levels in the reservoirs during

repairs

This impact could be very significant if the water levels are

lowered suddenly. However, the construction is planned to be

carried out particularly during Yala season where water level is

expected to be lower compared to other seasons.

No mitigation is required as the

lowering water level will not

adversely affect the bund or

any other related structures.

2. Seepage areas

along the D/S

toes (Figure

3.1B)

Slope stabilization

and seepage

control


i. Damage to aquatic habitat

Sediments, oil & grease and other chemicals that can be mixed

into tank water can pollute the aquatic habitat and will affect the

fish and other aquatic faunal species.

The construction area of the

tank should be temporary

barricaded


No negative impacts are envisaged on the farming community if

the work is carried out during the dry season.




The borrow material once brought to the site has to be

unloaded and stockpiled for subsequent use. This might block

the existing run–on and off paths which may create erosion

problems elsewhere.

However, the quantity to be handled seems to be small, hence


Same as above described for

the similar impact

ii. Raw water quality of surface water bodies Same as above described for


66




problems. However, the quantity to be handled seems to be

very low, hence adverse impacts anticipated would be

insignificant.

the similar impact

iii. Increase in vehicular traffic during transport of








the similar impact

iv. Health and sanitation of worker’s camps and that of




environment causing health hazards to both workers and

nearby residents. However, the number of workers to be

employed seems not many. Hence the impact is insignificant.


the similar impact

v. Management of construction waste and excavated






the similar impact

vi. Generation of noise, vibration and dust affecting the Same as above described for


67






the similar impact

3. Water

stagnating at

the dam

(Figure 3.1C)

Construction of

pond in D/S of tank

bund to collect toe

drain water at

0+067 m and

0+310 m


Positive impact on ecological environment as it will create better

habitats for the surrounding fauna.

No mitigation required


No negative impacts are envisaged





4. Encroachments

at the dam

(Figure 3.1D)

Consult the

unauthorized

settlers and

explain the need of

having a toe road

for the inspection

and safety of the

dam

Clear out the tank


No significant ecological impacts during construction is

envisaged


Impact on SocialEnvironment:

No impact on the economic activities of the people as they

have their own main income sources and lands other than the

encroached portion



68

reservation Impacts on Physical Environment:



d. Issues identified during the initial site visit

Issue Intervention Anticipated Impacts

5. The bund road

is with lots of

pot holes and

eroded places

(Figure 3.1F)

Construction of

access road from

0+000 m to 1+775

m

Construction of a

vehicle turning

point at the end of

bund road



Clearing weedy shrubs, grasses and trimming the branches of

the trees would create habitat loss for the faunal species that

use such habitats as their feeding, breeding and nesting

grounds. However, since there are enough similar habitats

available in the surrounding area, such species will get

adapted to the new conditions and hence the impact will be

very low or none.


the similar impact


The material to be extracted from the tank bed which is

inundated during the most of the time of the year. So there is a

very less possibility of spreading such species during material

extraction.


the similar impact

iv. Effect on fauna

There can be insignificant levels of noise and dust produced

during material transportation and construction work. In addition,

due to heavy machinery there may be temporary disturbances to

the animals (especially migratory birds) inhabiting the tank area.


the similar impact


69

However, the quantity of work will be less and hence the impact

will be low.

ii. Effect on aquatic habitat





the similar impact


iii. Impact due to Material Transportation

Transportation routes of the borrow material (earth and Gravel)

not associated with the residential area and hence impact will be

low or none


the similar impact

iv. Impact due to blockage of access

The bund road is not used as an access to residence or it is not

linked with other settlement. However, there will be a temporary

disturbance to the people those who access tank for their

domestic purposes.




Borrow material once brought to the site has to be unloaded and

stockpiled for subsequent use. This might block the existing run

– on and off paths which may create erosion problems

elsewhere.

However the quantity to be handled seems to be small, hence



the similar impact


70





problems. However, the quantity to be handled seems to be very

low, hence adverse impacts anticipated would be insignificant.


the similar impact

iii. Increasing the possibilities of erosion of the U/S/and D/S

slopes

Exposed areas of the bund are susceptible to erosion.


the similar impact

iv. Increase in vehicular traffic during transport of








the similar impact

v. Health and sanitation of worker’s camps and that of




environment causing health hazards to both workers and nearby

residents. However, the number of workers to be employed

seems not many. Hence the impact is insignificant.


the similar impact


71

vi. Management of construction waste and excavated






the similar impact

vii. Generation of noise, vibration and dust affecting the







the similar impact

6. Structural

failures of the

spillway such as

failure of

abutments,

sliding of

sections (Figure

3.1G)

Construction of

curtain wall at U/S

of spill


No significant ecological impact during the construction



No significant negative impacts during the construction are

envisaged as the construction will be carried out during dry

season and using coffer damning




Excavated and exposed areas of the bund are susceptible to

erosion

In addition to those, general impacts such as generation of

construction waste, excavated material, wastewater, generation

of noise and vibration and dust which affect the social and


the similar impact


72

biological environment could be envisaged. Since the amount of

work that has to be carried out is small, the impact is

insignificant

7. Malfunction of

spillway radial

gates

Repairing radial

gates by removing

corroded parts of

the gates

Replace seals and

cables and related

attachments

Provision of motor

driven

arrangements for

operation


No significant ecological impact during the construction




envisaged.





erosion

In addition to those, general impacts such as generation of

construction waste, excavated material, wastewater, generation

of noise and vibration and dust which affect the social and

biological environment could be envisaged. Since the amount of

work that has to be carried out is small, the impact is

insignificant


the similar impact

8. Leakage

through right

wing wall of

sluice and

suspected areas

in U/S (Figure

3.1H)

Repairs in D/S of

sluice

Construction of

Gabion wall for

slope protection

Providing



envisaged






73

emergency gates envisaged.


No significant impacts during the construction are envisaged


9. No bathing

steps and

inspection steps

Construction of

bathing steps at

0+100m,

0+500m,1+450 m,

and inspection

steps at 1+325 m

of tank bund



envisaged




envisaged.



No significant impacts during the construction are envisaged.

However, general impacts such as generation of construction

waste, excavated material, wastewater, generation of noise and

vibration and dust which affect the social and biological

environment could be envisaged. Since the amount of work that



the similar impact


facilities

Construction of

watcher hut and

storage area for

the field

equipments at the

left end of spillway



envisaged






74

envisaged.


No significant impacts during the construction are envisaged.

However, general impacts such as generation of construction

waste, excavated material, wastewater, generation of noise and

vibration and dust which affect the social and biological

environment could be envisaged. Since the amount of work that



the similar impact

11. Anchoring

boats along the

U/S slope of

dam cause

bund erosion

and scouring

(Figure 3.1I)

Construction of

boat yard in

Angamuwa tank at

1+500 m of tank

bund


i. Effect on aquatic habitat





the similar impact


There can be temporary impact to the fishermen, but there are

enough of other areas to carry out their activities and hence the

impact will be low/none





erosion


the similar impact


75

5.3 Implementation Schedules of Proposed Mitigation

The specific mitigation measures given in the Error! Reference source not found. should be

mplemented by the contractor when each and every intervention is done. In addition to the

specific measures, the contractor must adhere to the civil engineering best practices as

practical as possible. Most of such practices are described in ICTAD specifications and the

contractor is recommended to follow them when appropriate.

Time of the implementation of mitigation measures should be decided by the contractor and

they should be informed to the Project Engineer in advance and his approval should be

obtained. The key performing indicators (KPIs) for every mitigation carried out must be

worked out and should be informed to the PM for subsequent checks and balances. Once

the KPIs are accepted such indicators should be monitored by the PM to ensure that

measures are taken to minimize or avoid environmental degradation or pollution that is very

likely due to the said project.

It should be necessary that all mitigation measures mentioned in the report be implemented

by the contractor and for such implementation budgetary allocation must be set aside. It has

to be done during the bidding process and the allocation so kept must be utilized by the

contractor in an efficient manner.


76

5.4 Formal Clearances and Approval Needed

Error! Reference source not found. gives the details of the clearances and approvals for the project.

Table 5.2: Formal Clearances and Approval Needed

No

Issues / Activity /

Intervention needing the

permit or approval

The Reasons for the Approval (Law,

Act or enforcements etc.)

Authority from which

permit or approval or

Clarence is required

Prior Approval and Acts

1

National environmental

protection and quality

regulations under

Extraordinary gazette

notification No. 1534/18 and

No. 1533/16 of 2008 under

NEA section 32 & 23A, 23B

Environmental Protection Licenses (EPL)

from CEA, in particular prescribed

activities in gazette No. 1533/16 of 2008

(i.e., Concrete batching plants, treatment

plants, sewerage networks, mechanized

mining activities, etc.) are required during

the construction period and license need

to be obtained to collect, transport, store,

recover, recycle or dispose waste or

establish any site or facility for the

disposal of any waste during the

construction and operation period.

CEA and Local Authority

Environmental Protection

License (EPL) from CEA/

Divisional Secretariat for

identifying waste dumping

sites /Local Authority/

Pradeshiya Sabha for

waste collection and to

issue machinery permits

2 Mines & Minerals Act No.

33 of 1992

The act regulates the process of approval

required for exploration, mining, trading

and transport of geological material

(sand, earth, gravel, metal etc.)

Geological Survey and

Mines Bureau

Industrial Mining License

(IML) from Geological

Survey and Mines Bureau


77

6. CHAPTER 06 : MONITORING PLAN

6.1 Environmental Compliance and Monitoring

Environmental monitoring is required in order to make sure that the anticipated adverse

impacts are kept minimal with the implementation of mitigation measures as and when

required. The monitoring objectives are therefore focused on the mitigation of likely impacts.

In addition, compliance with the existing regulations and legislation is also guaranteed.

Table Error! Reference source not found. enumerates the summary of monitoring plan

(EMoP) required for the entire project.


78

Table 6.1: Summary of Monitoring Requirement

Specific

Intervention

Monitoring

Parameters

Monitoring

Frequency

Total Time

Period

Months

Responsible

Institution/

Person for

Implementation

Responsible

Key Persons

for Supervision

Framework of the

Institutional Arrangement to

Incorporate the Findings of

MP to Project

Implementation

Improvement

s to tank

bund U/S

slope and

bund crest

(0+000 m to

1+775 m)

Slope

stabilization

and seepage

control

Construction

of access

road from

0+000 m to

1+775 m

Construction

of a vehicle

turning point

at the end of

bund road

Method and

procedure of

stockpiling of

material

At the

beginning of

the

intervention

During the

whole

intervention

Contractor

Project

Manager or his

nominee

PM to inform the contractor

of the monitoring and the

contractor to submit the

reports as agreed; Reports to

be submitted to the Project

Office (PO) and then the

reports be evaluated by

World Bank (WB) and PO for

approval.

Number of

complaints

received on the

inconveniences

caused in the

neighborhood

As and when

received

During the

whole

intervention

Contractor

Project

Manager or his

nominee

Turbidity in the

working section of

the tank

When such

incidents

are found

During the

whole activity

Contractor

Project

Manager or his

nominee

As mentioned above The extent to

which the turbidity

plumes due to

erosion in the

downstream water

courses run

When such

calamities

occur

During the

stock piling

period

Contractor

Project

Manager or his

nominee


79

Specific

Intervention

Monitoring

Parameters

Monitoring

Frequency

Total Time

Period

Months

Responsible

Institution/

Person for

Implementation

Responsible

Key Persons

for Supervision

Framework of the



MP to Project

Implementation

Removal of

cleared

vegetation and

branches

When this

activity

takes place

When this

activity takes

place

Contractor

Project

Manager or his

nominee

As mentioned above

Stocks of stumps

removed

When this

activity

takes place

When this

activity takes

place

Contractor

Project

Manager or his

nominee

As mentioned above

Construction

of curtain

wall at U/S of

spill

Repairs in

D/S of sluice

Construction

of Gabion

wall for slope

protection

Providing

emergency

gates

The extent to

which the

turbidity plumes

due to erosion in

the downstream

water courses

When

turbidity

plumes are

found

During the

whole

intervention

Contractor

Project

Manager or his

nominee

As mentioned above

Timber logs

removed

When this

activity

takes place

When this

activity takes

place

Contractor

Project

Manager or his

nominee

As mentioned above

Removal of

cleared

vegetation and

When this

activity

takes place

When this

activity takes

place

Contractor

Project

Manager or his

nominee

As mentioned above


80

Specific

Intervention

Monitoring

Parameters

Monitoring

Frequency

Total Time

Period

Months

Responsible

Institution/

Person for

Implementation

Responsible

Key Persons

for Supervision

Framework of the



MP to Project

Implementation

branches

Construction

of boat yard

in

Angamuwa

tank at

1+500 m of

tank bund

Noise levels

When the

drilling is

done

During the

doweling

operations

Contractor

Project

Manager or his

nominee

As mentioned above

Vibration levels

When the

drilling is

done

When the

drilling is

done

Contractor

Project

Manager or his

nominee

Airborne dust

levels

When a

complaint is

received

During the

activity Contractor

Project

Manager or his

nominee

Cracks that

would appear in

other connected

structures

During the

activity

During the

activity

Contractor

Project

Manager or his

nominee

As mentioned above

Material

haulage from

borrow areas

Noise levels

When a

complaint is

received

During the

material

transport

Contractor

Project

Manager or his

nominee

As mentioned above


81

Specific

Intervention

Monitoring

Parameters

Monitoring

Frequency

Total Time

Period

Months

Responsible

Institution/

Person for

Implementation

Responsible

Key Persons

for Supervision

Framework of the



MP to Project

Implementation

Vibration levels

When a

complaint is

received

When a

complaint is

received

During the

material

transport

During the

material

transport

Contractor

Project

Manager or his

nominee

As mentioned above

Airborne dust

levels One in 10

vehicles of

borrow

martials

brought in to

the site

During the

material

transport

Contractor

Project

Manager or his

nominee

As mentioned above

Presence of

invasive species

Environmental Assessment for Rehabilitation of AngamuwaTank Draft Final Report

82

7. CHAPTER 07 : COST ESTIMATE OF ENVIRONMENTAL MANAGEMENT PLAN

Table 7.1: Cost Estimate of EMP

Issue Mitigation Details of Costing Itemized Cost

Activities such as

material

transport, soil

stockpiling, etc.

may result in air

pollution through

airborne dust. If

there are dwelling

units along

haulage routes

there may be a

minor temporary

adverse impact

during this period.

Dust emission due to

transport operations should

be controlled by wet

spraying and tarpaulin

covering in mandatory on

trucks/lorries which are used

for transporting materials

particularly in built up areas.

Sprinkling of water

has to be carried out

using bowsers, or

tractors where there

are dwelling unit only

when necessary.

Lorries and truck

should be covered

(with tarpaulin sheets)

when transporting

earth and gravel.

Sprinkling of water:

Bowser: Rs. 5,000 -

6,000 per bowser

Tractor: Rs. 2,500

per tractor

Covering with

tarpaulin sheets:

Rs. 200/m2

Health and

sanitation of

worker’s camps

and that of

residents in the

adjoining areas:

The temporary

camps if not

managed

properly may

create an

unhealthy

environment

causing health

hazards to both

workers and

nearby residents.

Proper sanitation facilities

should be provided on-site

for the workforce. Ideally,

this can be a pit latrine in

which the pit is located

above the ground water

table. Covering the deposit

(with earth or sawdust) is

necessary to prevent smells

and to discourage flies.

Costs involved in

providing pit latrines Rs. 10,000 – 15,000

Operation of

borrow pits

Erosion and

slides in borrow

areas occurring in

hillocks would

lead to loss of

Closure of borrow pits

properly

After borrowing the

slope/gradient of the area

should be graded to match

or blend with the existing

terrain.

The costs that may

incur involve grading

of borrow pit edges

Cost of construction

depends on the

scale of the borrow

pit. The typical cost

of rehabilitation

would be Rs.

500.00 / m2.


83

Issue Mitigation Details of Costing Itemized Cost

topsoil and

vegetation loss,

hence habitat

loss.

Re-establishment

of vegetation

would be

hindered due to

loss of fertile soil

Any borrow pits

on the tank bed

also should be

graded properly.

Plant the area with native

trees and water regularly


84

8. CHAPTER 08 : CONCLUSIONS AND RECOMMENDATIONS

8.1 Conclusions

The following conclusions could be deduced for the entire environmental assessment.

The project area does not have any environmentally sensitive features, endemic or

threatened flora and fauna specific to the neighborhood. No archaeological sites, cultural or

religious sites are found in the project area.

All the interventions are accepted without any specific environmental mitigation measures.

Nevertheless, best practices listed on the EMP should be practiced as practical as possible.

ICTAD specifications on civil engineering practices must be followed as and when

applicable.

Alternative route must be identified for the commuters on the bund when the bund

construction is in the progress. However, construction work should be complete as early as

possible so as to minimize the inconvenience caused in the neighborhood.

All the borrow sites need better managements in order to avoid or minimize pollution

potential and best practices for managing sites should be adopted.

The proposed project will therefore be carried out together with the implementation of

mitigation measures stated in this report.

8.2 Recommendations

The following recommendations are imperative to be adhered to for the management of the

environment during the project realization period.

Borrow site in the tank bed must be utilized with a proper rehabilitation and safety plan for

the protection of fauna inhabiting the area. All the other borrow areas should be accepted for

material exploitation only if proper approvals from the relevant authorities are obtained.

Engineering best practices must be recommended to be adopted by the contractor for the

sound engineering work.

When complaints are received from the neighborhood on the environmental issues,

immediate attention and solutions to such issues are recommended.

I

ANNEXES


II

Annex 1: Details of the Farming Community

Farmers who were interviewed individually

Serial

No Name Position Address TP No

1 D. M. K. H.

Dissanayake P.M. I M D Rajanganaya 0716317003

2 S. Thilina Development

Officer I M D Rajanganaya 0716423330

3 N Anuruddika Development

Officer I M D Rajanganaya 0712389129

4 N Saratha

Gaminie President

Pradesiya Saba,

Rajanganaya 0725458466

5 P Nihal

Wanniarachchie President Rajanganaya 0715153538

6 S Chaminda

Kumara Secretary

Fisheries Committee,

Angamuwa 0725152413

7 H M K Nimal

Jayatissa President

Track 6, Farmers

Association, 501,

Angamuwa

0726152034

8 K P Dhanaratna Secretary

Track 7, Jaya Sri, Farmers

Association, 700,

Angamuwa

9 W M Nimal

Samaraweera President

Kethsiri Farmers

Association, Track 9,

Gemunupura, Rajanganaya

10 Y G Gunaratna Farmer Track 8, Angamuwa,

Rajanganaya

11 W Seelawathie Farmer Track 8¸ Angamuwa,

Rajanganaya

12 A W Abeysinghe Farmer Track 8, Angamuwa,

Rajanganaya

13 U Nandawathie Farmer Track 8, Angamuwa,

Rajanganaya


III

14 W G Piyadasa Farmer Track 8, Angamuwa,

Rajanganaya

15 N Upali

Ranaweera President

Track 8, Angamuwa,

Rajanganaya

16 G G Anura Farmer Track 8, Angamuwa,

Rajanganaya

17 J Gunatilake Farmer Track 6, Angamuwa,

Rajanganaya

18 M Premawathie Farmer Track 6, Angamuwa,

Rajanganaya

19 J M Nandawathie Farmer Track 6, Angamuwa,

Rajanganaya

20 S. P. Sam Farmer Track 6, Angamuwa,

Rajanganaya

21 W Upali Farmer Track 6, Angamuwa,

Rajanganaya

22 D M Ariyaratna Farmer Track 6, Angamuwa,

Rajanganaya

Details of the group discussions that were held during the study

FGD Participants Total Venue

Female Male -

1 2 5 7

Kethsiri Farmers

Association,

Track 9,

Gemunupura,

Rajanganaya

2 2 4 6

7, Ela,

Angamuwa,

Track 7


IV

Annex 2: Details of the encroached farmer families

Name Employment Family size

G.H.Gamini Ornamenctal flcower

growing 5

M.Sunil Labor 3

H.A. Kularathna Farming 4

K.A. Jayathilaka Farming 4

M.R.Tennakoon Self employment 2

W.A.Irangani Farming 3

W.M. Karunadasa Private sector 4

S.Padmasiri Self employment ( Poultry

Farm) 4

A.G. Albert Framing 4

Total 9 35

S

Numbe

r

Name

Extent Property Impacted Details

Leng

th-m

Wid

th-m

Exte

nt-

m

Coconut-

No

Ban

ana b

ush

es-

No

Sha

llow

wells

Toile

ts

Pou

ltry

farm

1 G. H

Gamini 200 5 1000 15 0 0 0 0

Residential

land but no

impact on

the house

coconut

trees are

about 5m

away from

the bank

2 M.Sunil 150 5 750 0 15 0 0 0

No house

available.

Banana

bushes are

6m from


V

the bank

3 H.A

Kularathna 100 5 500 8 0 0 0 0

No house

available.

Coconut

trees are

5m from

the bank

4 K.A

Jayathilaka 150 5 750 5 20 0 0 0

Residential

land.

House is

far from

the bank.

Coconut

and

banana

are 6m

from the

bank

5 M.R

Tennakoon 75 5 375 2 0 0 0 0

Residential

land.

House is

far from

the bank.

Coconut

are 5m

from the

bank

6 W. Irangani 50 5 250 0 0 0 0 0

Bare land

but a

house is

being

constructe

d in a

place far

from the

bank

7

W.M

Karunadas

a

100 5 500 0 0 0 0 0 Bare land

8 S.Padmasir

i 150 5 750 4 0 1 1

1

(10x20

feet)

Residential

land.

House is

far from

the bank

but toilet,

well and

part of


VI

poultry

farm may

get

affected

these are

located

from 6m

from the

bank

9 A.G Albert 150 5 750 5 10 1 0 0

Residential

land,

house is

far from

the bank,

the trees

and the

well are

located

about 5m

from the

bank

total 975 5625 39 45 2 1 1

VI

Annex 3: Land area in Gravity and Lift irrigation systems in Angamuwa tank

FO Command area-Acers

Gravity irrigation system

Arunnalu – Track 6 252

Jayasri – Track 7 182

Mahasen – Track 8 298

Nethsiri – Track 9 232

Ruhunu – Track 10 246

Ranketha – Track 11 402

Predeepaloka – Track 12 358

Ekamuthu – Track 13 480

Pregathi – Track 13 144

Vijaya – Track 14 390

Jayamaha – Track 15 434

Youth FO – Track 16 530

Saraketha- Track 17 640

Sri Vijaya –track 18 227

Total 5194

Lift irrigation system

Track 6- BOP 397 Dimuthu 81

Track 6 BOP 716 Purasanda 284

Track 7 BOP 717/1 Suhada 59

Track 7 BOP 560/A Nava Jaya 111

Track 8 BOP 561 Pubudu 41

Track 9 BOP 560 Udara 220

Track 15 BOP 607 Track 11, 15 210


VII

Track 15 BOP 717/2-Ekamuthu 360

Total 987

Annex 4: Details of the cost benefit of an acre of paddy land in Angamuwa tank

Gross income Rs. Expenditure item Rs.

2,442 kg (110

bushel * 22kg) 85470/- (2,442*35) Ploughing (tractor) 8,500

Preparation of field

bank (activity 1) 3,600

Preparation of field

bank (activity 2) 4,800

Seed paddy 3,400

Basel fertilizer 600

sowing 4,800

Agrochemical 1 3,500


Second application

of fertilizer 600

Agrochemical 3 750


Third application of

fertilizer 600

Harvesting 7,500

Transport of paddy 2000

Drying of paddy 3,600

TOTAL 46,650

Note: Gross income Rs. 85470/-, total expenditure Rs. 46650/- therefore net income Rs

38,820 /=


VIII

Annex 5: Map showing the vicinity of Angamuwa tank


IX

Annex 6a. Earth and Gravel Borrow Sites for Angamuwa Tank interventions

Annex 6b. Earth and Gravel Borrow Sites for Angamuwa Tank interventions

Angamuwa Tank