Initial Environmental Examination (IEE) Report

Transcription

1 Initial Environmental Examination (IEE) Report for the Proposed Binathura Ela Mini-Hydro Power Project Thalagahalanda, Kuruwita, Rathnapura Submitted by Erathna Power Company (Pvt.) Ltd. No. 37-C, School Lane, Nawala November 2014

2 Project Title: Proposed Binathura Ela Mini-Hydro Power Project in Thalagahalanda, Kuruwita, Rathnapura Project Location: Thalagahalanda GN Division, Kuruwita DS Division, Rathnapura District Project Proponent: Erathna Power Company (Pvt.) Ltd., No. 37 C, School Lane, Nawala Project Approving Agency: Central Environmental Authority This Initial Environmental Examination Report (Final) for the proposed Binathura Ela Mini-Hydro Power Project at Thalagahalanda, Kuruwita, Rathnapura was submitted to the Central Environmental Authority Sabaragamuwa Provincial Office by Erathna Power Company (Pvt.) Ltd. Name of the Authorized Representative (Erathna Power Company (Pvt.) Ltd.) Signature Date : :.. :.. i

3 TABLE OF CONTENTS TABLE OF CONTENTS... ii LIST OF TABLES... v LIST OF FIGURES... vi List of Annexures... vii Executive Summery... viii CHAPTER 01: INTRODUCTION Project Background Project Scope, Objectives and Justification Objectives of the IEE Extent and Scope of the IEE Methodology for the IEE The Government policy, applicable terms, regulations and approvals Any Conditions laid down by State Agencies in Granting Preliminary Approval for the Proposed Project... 9 CHAPTER 02: DESCRIPTION OF THE PROJECT Description of the Project Name of the Project and Project Location Description of the Major Project Components Transmission line Methodology of Construction Site preparation and pre-construction activities Details of trees to be removed Phased development activities and time schedule Infrastructure facilities Work force Project funding and costs Other mini-hydro projects in the area Evaluation of Alternatives Comparison against No action alternative Alternative sites Alternative design, technology and construction techniques CHAPTER 03: DESCRIPTION OF THE EXISTING ENVIRONMENT Physical Environment Topography : Geology ii

4 Land use pattern of the project area Hydrology Biological Environment Assessment of Floral Diversity Assessment of Faunal Diversity Social Environment Project background Methodology for the socio-economic study Socio-economic profile of the project area Use of river water Villagers concerns CHAPTER 04: ANTICIPATED ENVIRONMENTAL IMPACTS Soil Erosion, Siltation and Slope Stability Soil erosion and siltation hazards River Bank Erosion Impacts during rehabilitation of access roads Loss of soil stability and increase of slope failures Hydrology and Water Quality Impacts Water quality impacts Waste generation and pollution due to worker camps Impacts on water quality and quantity of drinking water schemes Increases in water levels upstream under normal discharge due to the weir Increase in stream flood water levels Reduction of downstream flow of Binathura Ela Ecological impacts Impacts on terrestrial fauna Impacts on terrestrial flora Impacts on aquatic flora and fauna Impacts on ground stability Sociological impacts Impacts on bathing places and drinking water usage of downstream Existing water usage downstream : Impacts on land use and agricultural activities Noise, air pollution and impacts on existing roads Impacts due to rock blasting : Impacts due to material transportation iii

5 Impacts due to worker camps Impacts on irrigation and flood protection works CHAPTER 05: PROPOSED MITIGATORY MEASURES Mitigation of Soil Erosion, Siltation and Slope Instability Mitigation measures for soil erosion and siltation hazards Mitigation measures for river bank erosion Loss of ground stability and increase of slope failures Mitigation of Hydrology and Water Quality Impacts Steps to minimize the flood threat of the area Mitigation of reduction of downstream flow of Binathura Ela Mitigating impacts on drainage Mitigation of water quality impacts Mitigation of Ecological Impacts Mitigation of Sociological impacts Mitigating impacts on other river users Mitigating impacts on existing roads Mitigating impacts on agricultural activities Mitigation of impacts due to material transportation Mitigating impacts due to worker camps Mitigating impacts due rock blasting Catchment Protection CHAPTER 06: ENVIRONMENTAL MONITORING PROGRAMME Monitoring Program Structure Implementation of Monitoring Program CHAPTER 07: CONCLUSION AND RECOMMENDATION References Resource Persons Annexures iv

6 LIST OF TABLES Table 1.1: Estimated annual cost of power production under alternatives...3 Table 2.1: Project components, their location and land ownership...10 Table 2.2: Estimated budget of the Binathura Ela mini-hydro power project...34 Table 3.1: Ordinates of the flow duration curves...54 Table 3.2: Annual minimum flow rates at weir site...56 Table 3.3: Endemic and nationally threatened flora recorded in the project area...60 Table 3.4: Summary of faunal assemblage in the project area...62 Table 3.5: Endemic and threatened fauna recorded in the project area...64 Table 3.6: Fish species recorded in Binathura Ela and Kuru Ganga systems...65 Table 3.7: List of households interviewed...66 Table 3.8: Main sources of household income in the project area...67 Table 3.9: Main type of houses in the project area...68 Table 3.10: Use of river water by households...69 Table 4.1: Impacts due to construction of key project activities...78 Table 6.1: Environmental Impact Mitigation Measures and Monitoring Plan...92 v

7 LIST OF FIGURES Figure 1.1: Satellite Image of the Project Site...7 Figure 1.2: Project area on a 1:20,000 topographic map...8 Figure 2.1 (a): Project Layout and Land Plan Weir to penstock...12 Figure 2.1 (b): Project Layout and Land Plan Penstock to Powerhouse...13 Figure 2.2: Project Layout Plan Drawn on a Contour Map (original scale shrieked)...14 Figure 2.3: Layout of Project Components on a 1:10,000 contour map...15 Figure 2.4: Cross section and Hydraulic design of the Weir...17 Figure 2.5: Elevation profile at the weir location...18 Figure 2.6: General layout and design of the intake...19 Figure 2.7: Contour plan at the weir site and ponding area (original scale shrieked)...20 Figure 2.8: Design details of the Headrace canal...21 Figure 2.9: Design details of the Forebay Tank...22 Figure 2.10: Design details of the penstock...24 Figure 2.11: Design details of Anchor blocks...25 Figure 2.12: Design details of the Power station...27 Figure 2.13: Other existing and proposed mini-hydro power projects on Kuru Ganga...36 Figure 3.1: Topography of the study area...45 Figure 3.2: Map showing the geology of the project area Figure 3.3: Landslide risk in the project area...48 Figure 3.4: General land-use pattern of the project area...50 Figure 3.5: Locations of households and other infrastructure...51 Figure 3.6: Effective catchment area for Binathura Ela mini-hydro project...52 Figure 3.7: Annual rainfall variation (Keeragala station: 1935 to 2012)...53 Figure 3.8: Average monthly rainfall distribution (Keeragala Station)...53 Figure 3.9: Average monthly flows at the Binathura Ela MHP weir site...54 Figure 3.10: Flow duration curve for the average flow regime P(x) = 50%...55 Figure 3.11: Flow duration curve for the average flow regime P(x) = 75%...55 Figure 6.1: Structure and implementation of the monitoring program...91 vi

8 List of Annexures Annexure 1-A: Provisional Approval Letter- Sustainable Energy Authority Annexure 1-B: Ceylon Electricity Board LOI to purchase electricity Annexure 1-C: Ceylon Electricity Board - Grid interconnection proposal Annexure 1-D: Kuruwita Pradeshiya Sabha Conditional Approval Annexure 1-E: Kuruwita Divisional Secretariat Consent letter Annexure 1-F: District Planning Secretariat, Ratnapura - Consent letter Annexure 1-G: National Water Supply and Drainage Board Approval Annexure 1-H: Irrigation Department Approval Annexure 1-I: Department of Agrarian Development Approval Annexure 1-J: Forest Department clearance Annexure 1-K: Department of Archeology Approval letter Annexure 1-L: NRMC Department Report Annexure 1-M: District Landuse Planning Office, Ratnapura Annexure 2-A: Cross sectional profile of the river at the proposed weir site Annexure 2-B: Cross sectional profile at 25m upstream Annexure 2-C: Cross sectional profile at 50m upstream Annexure 2-D: Cross sectional profile at 100m upstream Annexure 2-E: Cross sectional profile at 25m downstream Annexure 2-F: Longitudinal section of the river across weir Annexure 2-G: Phased development activities and time schedule Annexure 2-H: Approvals for the Drinking water scheme Annexure 3-A: NBRO landslide hazard Investigation report Annexure 3-B: Hydrological study report Annexure 3-C: List of flora recorded on the study site Annexure 3-D: List of fauna recorded on the study site Annexure 4: TOR vii

9 Executive Summery After a 30-year long debacle, Sri Lanka s economy is now showing signs of robust growth. With growing investments, emerging new industries, rapidly developing infrastructure and anticipated improved life standards of its citizens, the demand for energy and power has increased significantly. As a result, Sri Lanka at present is struggling to meet the rising demand for power. In order to meet the rising power demand in the country at least by a certain percentage, especially through renewable energy sources as for the national interest, the project proponent Erathna Power Company (Pvt.) Ltd. is interested in constructing and operating a mini-hydro power plant using the waters of Binathura Ela at Thalagahalanda in the Kuruwita Divisional Secretariat Division of the Ratnapura District. The encompassed catchment area for the main water source is approximately 7.14 km 2. The water intercepted by constructing a weir across Binathura Ela will be transferred through a headrace canal to the forebay, and then to the powerhouse located on the left bank of Kuru Ganga via a penstock pipe. A pre-feasibility study for the project at the above location has been already conducted and accordingly, the project proponent wishes to commence the project subjected to applicable legal framework and environmental guidelines recommend by relevant government agencies. The total investment on this project is estimated to be SLR million. The key project features are as follows. The gross head is 70m. The weir is designed to have a maximum height of 1.5m from the river bed (293.5m AMSL). Length of the weir crest is 18m and the crest is at 295m AMSL. Water from the intake is channeled through 273m long 0.8x0.6m box headrace canal to the forebay tank. The forebay tank has a capacity of approximately 700m 3. A penstock of 980m in length, installed above ground will be used to convey water from the fore-bay tank to the powerhouse. The powerhouse will be at 225m AMSL on the left bank of Kuru Ganga. It will have an installed electricity generation capacity of 700 kw to add 2.1GWh annually to the national grid. The IEE study found that, owing to its magnitude and design, the proposed project will have comparatively low negative impacts on the environment. Most of these impacts are location specific and short term, which will arise during the construction period. No significant impacts on bio-physical environment can be anticipated. However the main concern is the probable alterations to freshwater stream Binathura Ela where the weir will be viii

10 built. As a result of water harvesting, flow rate and the water levels will be reduced, and this may lead to changes in the biological community inherent to these freshwater ecosystems. Several nationally threatened freshwater fish species were recorded from Binathura Ela downstream. However, only a small stretch (about 150m) of Binathura Ela will be affected by this condition. Mitigatory measures have been proposed in the Environmental Management Plan to negate such impacts. The project is located in a moderately populated village (Lassekanda GN division). Waters of streams in project stream is used by families in the vicinity for drinking, bathing, washing and agricultural purposes. Hence the proposed project possesses some negative impacts on the social environment. However, appropriate mitigatory measures including initiating a community drinking water system for affected households have been taken. On the other hand, the proposed project will bring significant positive impacts to the development of the area by upgrading existing rural road network and boosting economic opportunities for locals. As most of the lands required for the proposed project have already been acquired under Adavikanda MHP project, possible conflicts that can arise in acquisition of new lands is minimal. As described in the environmental management and monitoring plan, the project proponent is committed to follow acceptable environmental guidelines in implementing the proposed mini-hydro project. Although the proposed project is driven by reasonable profit motives, it contributes to Government s future vision and target to achieve 20% of the total supply of energy through renewable forms by The proposed project will bring substantial foreign exchange savings to the economy while producing green energy at a low environmental cost. Hence, the proposed project is of national importance. Considering all factors, it can be concluded that it is favorable to implement the proposed project subjected to environmental regulations imposed by the project Approving Agency; the CEA and other relevant state regulatory bodies. ix

11 CHAPTER 01: INTRODUCTION 1.1. Project Background With growing investments, emerging new industries, rapidly developing infrastructure and anticipated improved life standards of its citizens, the demand for energy and power has increased significantly. As a result, Sri Lanka at present is struggling to meet the rising demand for power. At present, over 90% of the households in the country have access to national grid electricity. In the power sector, the installed grid capacity for electricity generation from hydro, thermal and wind power presently stands at 3141 MW (Sustainable Energy Authority, 2011). With Sri Lanka s large hydro power resources have already been exploited, the Government of Sri Lanka and the Ceylon Electricity Board (CEB) has turned to thermal generation in order to increase the installed capacity to meet the rising demand. As such, the thermal power presently accounts for the greatest share of 53.8% (1690 MW) of the installed capacity, followed by major hydropower (38.4%). However, power from thermal generation comes at a higher economic and environmental cost to the country. Given Sri Lanka s lack of coal resources, the country will have to rely on expensive coal imports, which is likely to affect the trade deficit. Besides, thermal power generation causes numerous environmental issues including air pollution and greenhouse gases emission. Such economic and environmental concerns have shifted the emphasis on renewable energy sources domestically as well as globally. The Government of Sri Lanka (GOSL) has already set a target of achieving 20% of the total supply of energy through renewable forms by Sri Lanka s New Renewable Energy (NRE) sector mainly comprises of mini-hydro, biomass, solar and wind power generation. The contribution of country s NRE sector to the installed capacity presently stands at 7.7% i.e. 241 MW (Sustainable Energy Authority, 2011). Minihydro power generation projects have been identified by the GOSL as a major means of achieving its renewable energy targets. Mini-hydro power plants accounts for 84% of the NRE sector s 241 MW installed capacity (Sustainable Energy Authority, 2011). Presently, 94 plants with 201 MW total capacity are in operation and, each year saves approximately Rs. 17 billion to the national economy by substituting high cost thermal generation (Small Hydro-Power Developers Association, 2013). Sri Lanka s small hydro potential is estimated to be around 600 MW, and significant portion of small hydro potential still remains to be developed. 1

12 This report elaborates the environmental feasibility of implementing a new mini hydro power project across Binathura Ela at Thalagahalanda in the Kuruwita Divisional Secretariat Division of the Ratnapura District, proposed by Erathna Power Company (Pvt.) Ltd. The proposed project has an installed electricity generation capacity of 700 kw to add 2.1GWh annually to the national grid. The total investment on this project is estimated to be LKR million Project Scope, Objectives and Justification Scope: In order to meet the ever rising power demand in the country through renewable energy sources as for the national interest, and support the GOSL strategy of achieving the set renewable energy targets, the project proponent, Erathna Power Company (Pvt.) Ltd. is intending to construct and operate a mini-hydro power plant using the waters of Binathura Ela at Thalagahalanda in the Kuruwita Divisional Secretariat Division of the Ratnapura District. The encompassed catchment area for the main water source is approximately 7.14 km 2. The water intercepted by constructing a weir across Binathura Ela will be channeled via a headrace canal and a penstock to the powerhouse located at the left bank of Kuru Ganga. The project components span over two villages; Witharampanguwa and Lassekanda. The pre-feasibility study, level surveys, hydrology studies and optimization studies carried out for the implementation of this project indicate that the 70m head lying at proposed weir location and power house location can be easily utilized to generate 2.1GWh of renewable energy annually. Accordingly, the project proponent wishes to implement the project subjected to applicable legal framework and environmental guidelines recommend by relevant government agencies. Objective: The main objective of the proposed project is to design, construct and commission a minihydro renewable energy project with an installed electricity generation capacity of 700 kw using the waters of Binathura Ela at Thalagahalanda in the Kuruwita DS Division of the Ratnapura District to add 2.1GWh annually to the national grid. 2

13 Justification: Within the framework of sustainable development, the proposed project can be justified on economic, environmental and social grounds. Economic aspects In the interest of speedy capacity augmentation, the GOSL has focused on thermal generation as a short to medium term measure. Even at present, over 80% of the power requirement is generated by thermal power. In this background, the proposed project is economically justified under following scenarios. Variety of non-renewable fuel types are used in power generation. According to the figures published by the Public Utility Commission (2012), their prices are as follows: Heavy fuel: Rs. 65/l, Naptha: Rs. 90/l; Low sulfur heavy fuel: Rs. 75/l and Auto diesel: Rs. 115/l. Using conservative figures for Per Unit costs of production (1kWh) for selected fuel types, the estimated annual cost to produce 2.1GWh power under each scenario is given in Table 1.1. Table 1.1: Estimated annual cost of power production under alternatives Fuel type Per unit cost of production (1kWh) Estimated cost to produce 2.1 GWh/Year Coal Rs Rs. 17,430, Heavy fuel Rs Rs. 30,240, Auto diesel Rs Rs. 44,100, The proposed mini-hydro power project is expected to generate 2.1GWh annually. Taking both project lifespan and production cost of common non-renewable energy options into account, the GOSL will be able to gain substantial foreign exchange savings by commissioning the proposed power plant. Even against the least cost alternative (using coal), the annual savings are approximately Rs million/year. This can help Sri Lanka to reduce its overall fossil fuel consumption, thus improving energy security. Environmental aspects The renewable electricity generated by the project will displace electricity produced by fossil fuel power plants on the grid. By displacing the electricity generated with fossil fuel in the local grid, the Project activity will also reduce GHG emissions. The project activity will reduce greenhouse gas emissions in Sri Lanka compared to a business-as-usual scenario. Using conservative figures, potential emission reductions can be estimated as follows; 3

14 Net Electricity Generated by the project = 2100 MWh/year Grid Emission Factor (CEB Grid) = tco 2 /MWh Baseline Grid Emissions per year = tco 2 As the proposed project will have zero CO 2 emissions, the estimated emission reductions through implementing the project will be tons CO 2 /year. Further, the electricity produced by the project will displace electricity produced by fossil fuel power plants on the grid, leading to lower overall emissions of SO x and NO x from the grid as a whole. Social aspects The proposed project will generate numerous employment opportunities, boosting the local economy. The construction phase will involve about 30 unskilled laborers and 15 skilled laborers while the operational phase will employ about 6 unskilled, and 4 skilled personal. At the request of the local stakeholders, the project proponent will also implement local infrastructure developments including upgrading of footpaths and initiating a drinking water supply scheme for affected households Objectives of the IEE In general, the overall objective of the Initial Environmental Examination (IEE) is to identify possible impacts of a prescribed project during the initial project designing stage, and determining whether the impacts are significant. To facilitate the evaluation process of the Project Approving Agency (PAA); the Central Environmental Authority, an IEE report was prepared with special emphasis on environmental and socio-economic aspects of the proposed project. Accordingly, the main objectives of the IEE pertaining to the proposed project are as follows. Provide a clear description of all project activities to be carried out during the project period Identify all possible physical, ecological, and socio-economic impacts that can arise due to the proposed mini-hydro project Provide mitigation measures to control/reduce negative environmental and socioeconomic impacts of project activities Ensure that the proposed project is environmentally sound and sustainable, while being economically feasible 4

15 1.4. Extent and Scope of the IEE Binathura Ela originates at the mountain in the western hills of Adam s Peak at an elevation of 540 meters above assumed Mean Sea Level (AMSL) and at its upper reaches flows steeply westerly through the Peak Wilderness Sanctuary and thereafter converges Kuru Ganga at an elevation of 295m AMSL. The proposed project plans to intercept waters of Binathura Ela upstream by constructing a weir across the stream and transfer water through an closed headrace channel to the fore-bay tank, and then carrying the water through a penstock to the powerhouse located on the left bank of Kuru Ganga. After power generation, tailrace releases water to Kuru Ganga. The headrace canal and penstock path mostly laid parallel to Kuru Ganga with substancial diversions in certain parts. It is laid over stream reservation/state lands and mostly private home gardens. Figure 1.1 shows the satellite image of the project site. The present study covers a core project area of 100m upstream from the location of the weir (Binathura Ela) to 100m downstream from the tailrace lengthwise and 60m wide strip each side from the river bank. Similarly, an area of 10m both sides to the proposed headrace channel and penstock pathway were also included to the study area (the study area is indicated by dashed lines in Figure 1.1). The IEE report was developed in line with the Terms of Reference (TOR) specified by the Central Environmental Authority, Sabaragamuwa Provincial Office (Annexure 4). Accordingly, it comprises baseline data on existing physical, ecological, economic, and social conditions of the project area. Details of all project activities/components, the project environment, possible significant environmental impacts due to project activities and mitigatory measures have been particularly stressed in the IEE. An environmental monitoring program is also provided Methodology for the IEE Preparation of the IEE report was done by an independent multi-disciplinary team of consultants on behalf of the project proponent. Following tasks were undertaken during the preparation of IEE. Conducting regular meetings with the project proponent to discuss various projectrelated matters arise during the IEE 5

16 Gathering secondary information pertaining to the proposed project, project type, activities and the affected environment (both biological and socio-cultural). Collection of appropriate secondary information and statistics from government institutions and Local Government Authorities A field visit by the multi-disciplinary team of consultants to the proposed project area to make an appraisal of the physical, biological and social environment, and evaluate potential environmental impacts that can arise as a consequence of project activities After in-depth analysis of primary and secondary information, recommendations were made to minimize negative environmental impacts of the proposed project. These measures were further incorporated into the Environmental Management and Monitoring Plan The Government policy, applicable terms, regulations and approvals The GOSL in general has a favorable policy towards encouraging private sector involvement in renewable energy generation, especially since The Sustainable Energy Authority was established to facilitate this process. The GOSL future vision statement Mahinda Chinthana, also emphasize the need for expansion in the renewable energy sector and set clear targets to achieve 20% of the total power demand from renewable forms by the year Despite having favorable government policies, the proposed project needs the approval of several government institutions for operation. These include; Provisional Approval from the Sustainable Energy Authority Letter of Intent (LOI) and Grid interconnection proposal by Ceylon Electricity Board Environmental clearance from the CEA Construction clearance from Divisional Secretariat and Pradeshiya Sabha Approval by Irrigation Department Approval of National Water Supply and Drainage Board Approval of Department of Archeology Approval of Department of Agrarian Development The Project Proponent shall obtain and maintain valid licenses and authorizations from relevant state institutes prior to, and during the implementation of the project. 6

17 Kuru Ganga Binathura Ela Figure 1.1: Satellite image of the project location indicating the study boundary 7

18 Powerhouse Forebay Weir Figure 1.2: Project area on a 1:20,000 topographic map 8

19 1.7. Any Conditions laid down by State Agencies in Granting Preliminary Approval for the Proposed Project Several state agencies are directly involved in granting approval for the proposed project and hence can be considered as important stakeholders. Any conditions laid down by these state agencies below in granting approval for the proposed project shall be honored by the project proponent. Please refer to Annexure 1 for approvals already granted and obtained by the Project Proponent. Sustainable Energy Authority - Provisional Approval (Annexure 1-A) Ceylon Electricity Board LOI to purchase electricity (Annexure 1-B) Ceylon Electricity Board - Grid interconnection proposal (Annexure 1-C) Kuruwita Pradeshiya Sabha Conditional Approval (Annexure 1-D) Divisional Secretariat-Kuruwita Consent letter (Annexure 1-E) District Planning Secratariate, Ratnapura - Consent letter (Annexure 1-F) National Water Supply and Drainage Board Approval (Annexure 1-G) Irrigation Department Approval (Annexure 1-H) Department of Agrarian Development - Approval from the Ratnapura District Office (Annexure 1-I) Forest Department Consent letter (Annexure 1-J) Department of Archeology Approval letter (Annexure 1-K) NRMC Department Report (Annexure 1-L) Ministry of Lands and Land Development LUPPD District Landuse Planning Office, Ratnapura (Annexure 1-M) 9

20 CHAPTER 02: DESCRIPTION OF THE PROJECT 2.1. Description of the Project Name of the Project and Project Location The proposed site is located in Thalagahalanda in the Kuruwita Divisional Secretariat Division of the Ratnapura District. The proposed power house can be accessed by motoring along Colombo - Kuruwita route (78 km) and turning left at Kuruwita to proceed along Kuruwita - Erathna to reach the powerhouse location. The components of the 700 kw proposed mini-hydro power project span over Witharampanguwa, Lassekanda villages in Kuruwita Pradeshiya Sabha area, Kuruwita D.S. Division, in Ratnapura District, Sabaragamuwa Province. The proposed plant will add 2.1GWh annually to the national grid. The proposed project spreads over both State and Private LandsVarious project components, their locations and ownership of the land is summarized in Table 2.1. Table 2.1: Project components, their location and land ownership Lot No. 1 Name of Land Containing in Extent (Ha) Name of Claimant Gurumorahinnemukalana Telkekunagawamukalana The State 2 do Alternate Power Systems (Pvt) Ltd 3 do The State 4 do The State 5 do Alternate Power Systems (Pvt) Ltd 6 do The State 7 do The State 8 do Alternate Power Systems (Pvt) Ltd 9 do The State 10 do The State 11 do The State 12 do The State Telkekunehena, Mahagalahena & 13 Kadurugahagawahena Alternate Power Systems (Pvt) Ltd 14 do The State 15 do The State 16 Lellawalamukalana The State 17 do Alternate Power Systems (Pvt) Ltd 18 Gallenagawawatta Private Land 19 Rukattanagawahena Private Land 20 Gallenagawawatta Private Land Total

21 Total land area utilized by the project is about 0.57 ha (please refer Figures 2.1 (a) and (b) for Lot numbers and land ownership). All major project components including the weir, forbay, and powerhouse are located in Lassakanda GN division (a letter of approval by LUPPD is attached in Annexure 1-M). Proposed 33kV grid line from hydro power plant to the CEB interconnection point is planned to be laid along the same access road which is proposed to the Power House, thereby optimizing the use of existing roads and reducing environmental impact. Length of the proposed transmission line is approximately 500 m. Basic design parameters of the project are as follows. General Development Province Sabaragamuwa District Ratnapura Name of River Binathura Ela Type of the Scheme Run-of-River Gross Head 70m Net Head 66m Installed Capacity 700kW Annual Energy Generated 2.1 GWh Hydrology Catchment Area at intake Site 7.14 km 2 Annual rainfall 5152 mm Design Discharge 1.27m 3 /sec Design Flood Discharge 164 m 3 /sec (once in 100 years) Project Layout Plan The project comprises of a low diversion Weir, Headrace Channel, Forebay Tank, Penstocks, Powerhouse, Tailrace, and Switchyard on the left bank of the river. This is a run-of-river development, where water is not stored in a reservoir, and is used only as it is available. The weir will be located on Binathura Ela upstream. The Full Supply Level will be 295m AMSL. The short open channel and the forebay will be located downstream and continue in a channel with a box section up to the forebay tank. The penstock will be located on the left bank of Kuru Ganga with the tailrace discharging at 225 m AMSL. Composite land plan for the entire project is provided in Figure 2.1 (a) and Figure 2.1 (b). Figure 2.2 illustrates the project layout plan drawn on a contour map. Figure 2.3 indicates the project components on a 1:10,000 contour map. 11

22 Figure 2.1 (a): Project Layout and Land Plan Weir to penstock 12

23 Figure 2.1 (b): Project Layout and Land Plan Penstock to Powerhouse 13

24 Figure 2.2: Project Layout Plan Drawn on a Contour Map (original scale shrieked) 14

25 Binathura Ela Proposed Mini-Hydro Power Project: Layout of Project Components Figure 2.3: Layout of Project Components on a 1:10,000 contour map 15

26 2.1.3 Description of the Major Project Components Weir A weir will be constructed across the Binathura Ela at the location specified below; GPS coordinates: N 6 o , E Location of the proposed weir is shown in Plate 2.1. Weir location Plate 2.1: Location of the proposed weir The proposed height of the weir is 1.5 m and the length is approximately 18m. The weir is designed as a concrete gravity structure with dowels provided for added safety against sliding. The Full Supply Level (FSL) of the pond will be at 295 m AMSL. Figure 2.4 shows the cross section of the weir structure along with its design parameters. Elevation profile at the weir location and the view from above is illustrated in Figure

27 Figure 2.4: Cross section and Hydraulic design of the Weir 17

28 Figure 2.5: Elevation profile at the weir location The flow diversion weir is used to raise the level of the water at the intake point to ensure that the required quantity of water is directed into the headrace canal. As the project is run of the river type, minimal storage is required at the weir. The combined weir/ intake structure is designed in order to obtain the maximum spill length for river water, in order to minimize upstream water levels during floods to reduce time of bridge inundation. Therefore the penstock intake wall is also designed to act as a part of the spillway. The intake will be a closed reinforced concrete conduit with a flow area of 2 meter in width and 1.2 meters in height, and will slightly project into the pond through the weir. There will be trash bars spaced at 75 mm to prevent twigs etc. entering the channel and provision for a stop-log gate. Intake will be designed for a flow of 1.27m 3 /s without formation of a vortex. General layout and design of the proposed weir is given in Figure

29 Figure 2.6: General layout and design of the intake Un-gated opening will be placed in the weir to maintain sufficient minimum water flow downstream to ensure the survival of aquatic biota, and the size of the opening is to be determined by the technical committee to the proposed project under the direction of Department of Irrigation. The cross-sectional profiles for following locations in Binathura Ela are provided in Annexures indicated below. Cross sectional profile of the river at the proposed weir site: Annexure 2-A Cross sectional profile at 25m upstream: Annexure 2-B Cross sectional profile at 50m upstream: Annexure 2-C Cross sectional profile at 100m upstream: Annexure 2-D Cross sectional profile at 25m downstream: Annexure 2-E Longitudinal section of the river across weir: Annexure 2-F Ponding Area Analysis of the upstream longitudinal section of the river (Annexure 2-F) and the contour plan at the weir site (Figure 2.7) indicates a gradual incline of the river bed upstream. Due to this morphology, the resulting shallow ponding area is unlikely to extend beyond approximately 50m from the weir upstream. Ponding area is in parallel with three residential places that may be affected due to construction of weir. 19

30 Figure 2.7: Contour plan at the weir site and ponding area (original scale shrieked) 20

31 A foot path used by villagers to cross Binathura Ela during dry periods will be inundated due to ponding permanently. However, the dry period is restricted to only few months hence the path is not regularly utilized by villagers. An alternative footpath is also available approximately 40m downstream of the wear. Headrace Canal The entire length of the channel from the intake will be a closed conduit built into the left abutment to prevent the entry of floods and to attenuate the flow through the conduit during high floods. A side spillway will be provided in the open channel immediately downstream of the closed conduit near the forebay tank to spill the excess water entering at high flood levels. The forebay will be located downstream of the gate and will incorporate a distilling chamber with a sloped bed for easy ejection of silt and a trash rack. The headrace channel will be boxed structure as dictated by the terrain and will be reinforced concrete. Size of the headrace channel will be 0.8 meters in width and 0.6 meters in height (Figure 2.8). The length of the channel will be 273 meters. The conduit will be located on columns in order to minimize earth-excavation in unstable slopes. The contour plan for the headrace canal is provided on Figures 2.3. Figure 2.8: Design details of the Headrace canal 21

32 Forebay Tank The forebay location is an abandoned crop land, vigilantly selected so as to avoid thick vegetation area of the forest at following GPS location. This is a state land where part been acquired for the Adavikanda Mini hydro project by Alternate Power Systems (Pvt.) Ltd. Figure 2.9: Design details of the Forebay Tank 22

33 Length of the forebay is approximately 14.6m and the maximum width is 7.5m. Maximum depth is 9.5m. The total capacity of the forebay is 700m 3. The detailed design of the forebay tank is provided in Figure 2.9. (GPS coordinates: N, E) Penstock The penstock will be 980 meters long with a drop of 70 meters. Penstock diameter was selected with a range of 800 mm to 500 mm for penstock optimization (Figure 2.10). There are 14 anchor blocks. The penstock will be supported over the piers by saddle supports with a suitable sliding interface. Anchor blocks will comprise of reinforced concrete structures with rubble masonry to provide additional mass required against sliding (Figure 2.11). Power Station The powerhouse will be located on the left bank of Kuru Ganga and 200m from the Batadomba road. The powerhouse will be located to ensure good foundation conditions and to be safe from high floods of Kuru Ganga. Floor elevation at the powerhouse location is 225m AMSL. Location GPS coordinates: N, E The Powerhouse building is a 12.3m x 13.9m two storied structure, with the upper floor containing the control equipment, control module, operator s room, office etc., while the ground floor containing the turbine generator units and associated control gear. It will be a reinforced concrete structure with hollow cement block walls and will have an erection bay and offices. The roof will have steel trusses and powder coated steel cladding. An open tailrace channel will convey the tailrace water to the river. Detailed design of the power station building is provided in Figure The powerhouse will have two Francis type turbines coupled to Synchronous Generators. Other powerhouse equipment will include 0.6 m diameter Inlet Valves, Governor Oil Pressure Systems, Medium Voltage Switchgear, Low Voltage Switchboard, Control, Monitoring and protection System and the Powerhouse Crane. Complete G59 protection system will be incorporated as per the Ceylon Electricity Board requirements. The switchyard will be located close to the powerhouse and will have the generator transformers and the service transformers and the connected switchgear. The terminal tower of the 33 kv transmission line will be located at the end of the switchyard. 23

34 Figure 2.10: Design details of the penstock 24

35 Figure 2.11: Design details of Anchor blocks 25

36 Tailrace channel After power generation, water will be released to Kuru Ganga and a relatively short tailrace channel which is approximately 7.5m in length, 1.5m in width and 1m height is used for this purpose. Temporary Structures Several temporary structures will be required during the construction phase and their locations are as follows; Contractor s office: at powerhouse sites Site engineer s office: at powerhouse site Storage yards: at powerhouse site and forebay site Labour camps: at powerhouse sites Transmission line Proposed 33kV grid line from hydro power plant to the CEB interconnection point is planned to be laid along the same access road/footpath which is proposed to the Power House, thereby optimizing the use of existing roads and reducing environmental impact. Length of the proposed transmission line is approximately 500 m. Transmission line is located on government lands/road reservations. No trees of significance (over 10cm dbh) need to be removed for the construction of transmission line, access roads or any other project components. However, about 60 tea bushes need to be removed along the penstock path. 26

37 Figure 2.12: Design details of the Power station 27

38 Summary of key project features Weir & Intake Height 1.5m Length 18m Weir crest 295m AMSL Type of Intake Side Intake Size of Intake Opening 2 wide and 1.2 m high with Open Channel, supported on columns Type Rectangular Box Headrace channel Total Length Structures Channel Size 273 m Boxed 0.8m wide x 0.6m high Forebay Capacity of Forebay 700 m 3 Penstock Material Steel Penstock Length of Main Pipe 980 m Size of main pipe (Dai/thickness) 10mm, 10mm, 12 mm, 12 mm Design Discharge 1.27 m3/sec Design Net Head 66 m Powerhouse Type Surface Floor Elevation 225 AMSL Number of Units 01 Turbine Type Francis, Horizontal Shaft Number of Units 01 Capacity 700 kw (each) Generator Type AC Synchronous Related Power 1250 kva (Three Phase) Number of Units 01 Frequency 50 Hz Power Factor 0.8 (Lagging) Switchyard Type Transformer Capacity Rated Voltage Outdoor, Conventional 1250kVA 415/33,000 V (set-up) Transmission Interconnection Transmission line Length 0.5 km Transmission Voltage 33 kv 28

39 Methodology of Construction Material to be used The main civil works of the mini hydro development include the construction of diversion weir, headrace, forebay, penstock, powerhouse, and access roads. For civil constructions, sand, cement, aggregates of appropriate diameter, reinforcement steel and low grade timber and plywood will be used. Welded steel pipes will be used for the penstock. All materials will be sourced from the market and will be transported to specific sites manually from memorable access points. Method of installations, engineering techniques and machinery to be used The combined weir/ intake structure was designed in order to obtain the maximum spill length for river water, in order to minimize upstream water levels during floods to reduce time of bridge inundation. Therefore the penstock intake wall shall also be designed to act as a part of the spillway. The weir will be designed as a concrete gravity structure with dowels provided for added safety against sliding. The intake will be a closed reinforced concrete conduit with a flow area of 2 meter in width and 1.2 meters in height, and will slightly project into the pond through the weir. There will be trash bars spaced at 75 mm to prevent twigs etc. entering the channel and provision for a stop-log gate. Penstock of welded steel pipes will be installed on concrete piers by saddle supports with a suitable sliding interface. Anchor blocks will comprise of reinforced concrete structures with rubble masonry to provide additional mass required against sliding, and these will be placed where appropriate. Adequate drainage will be provided around support columns to prevent erosion. On-site welding machines will be used to connect steel penstock pipes. Standard engineering practices with minimum environmental damage will be followed during construction phase. During the site preparation and construction phases, equipment such as small backhoe or excavator, and transport vehicles (up to points accessible by vehicles) will be used Site preparation and pre-construction activities Major construction activities involved in the proposed project are as follows; Site preparation works: land clearance, excavation and developing access roads 29

40 Civil construction works: construction of weir, the water passages/penstock, forebay, powerhouse, and access roads Electro-mechanical works: installation of turbines, transformers, generator, and switchgear etc. Transmission line from switch yard to CEB grid connection point The project components spans over both state lands and private agricultural lands/home gardens. Large scale site preparation, clearing or excavation activities are not required as the project components have been designed taking into consideration the natural features of the environment and the topography to minimize such requirements. Access roads During the pre-construction process, there is a necessity to construct access roads or clear up foot paths particularly to the weir and the power house. An unpaved access road to the proposed weir already exists (Plate 2.2). This road will be further improved under the project to facilitate vehicle access during construction phase. The approximate length of this section is about 100m. Rest of the access roads has already been concreted and some were developed under Adavikanda mini-hydro project by Alternate Power System (Pvt.) Ltd. Plate 2.2: Access road to the proposed weir 30

41 The proposed power house can be accessed by motoring along Colombo - Kuruwita route (78 km) and turning left at Kuruwita to proceed along Kuruwita - Erathna to reach the powerhouse location. A concreted access road of the length 500m will be constructed to the power house location. As all the access road development activities are small scale civil construction works, use of heavy machinery is not required and manual labour will be used predominantly. Blasting Rock boulders of varying sized rest on the stream bed as well as on both sides of the stream at proposed weir location. More boulders are accumulated on the left bank of the stream at weir location. Some medium sized moveable rock boulders detached from the parent rock due to strong floods need to be removed before weir construction. Chemical blasting will be done under the close supervision of a civil engineer to remove such boulders. The chemical traded as Expansive Mortar will be used for this purpose. It is a soundless, safe and nonexplosive demolition agent. This product is nonpoisonous and silent, which is chiefly made of aluminum acid, calcium, silicates, cement, and slow coagulant. The process requires drilling holes in the rock, pouring the blasting agent and letting it set and expand, which will result in cracks. The reaction time of Expansive Mortar to crack stones varies from 24 to 76 hours depending on the rock material. As the foundation of the weir predominantly lies on solid bed rock, minor rock excavations may be required at both abutments. No blasting activities will be required elsewhere of the project other than at weir location. Excavations and Cutting and filing works Soil excavation work will be required for the construction of anchor supports and piers for headrace canal and penstock. Minimum excavation in ground for anchor supports and piers will be 600mm. Excavated soil will be utilized in back-filling; hence no disposal will be required. Excavation of soil will be required during the construction works and it can be balanced in cut and filling. Construction of powerhouse building also requires major excavation work. The overburden and excess soil can be used in relevant on-site filling purposes as well as in access road development. Excavation works involved in construction activities will be predominantly done using manual labour. Machinery such as a small backhoe/excavator may be used for site preparation at powerhouse location. 31

42 Clearance of vegetation Vegetation clearance of major significance will not be required as most project components are located on lands acquired under Adavikanda mini-hydro project by Alternate Power System (Pvt.) Ltd. Weir intake and the first section of headrace canal (about 75m) located on stream bank reservation are designed to avoid major trees. Most parts of the headrace canal and penstock are located on home gardens/agricultural lands. However, the proposed penstock paths mostly go parallel with the penstock path of Adavikanda mini-hydro project and located within the strip cleared and acquired by Alternate Power System (Pvt.) Ltd (Plate 2.3 and 2.4). Before commencement of constructions, the powerhouse site and the access road to the power house require minor clearances of vegetation consisting mainly of bushes and small trees. Other construction activities, including temporary structures Other construction activities include the construction of cofferdam and temporary structures such as contractor s office, storage yards, labour camps etc. Sandbags with clay cores will be utilized in cofferdam construction. GI sheets and low grade wood rafters may be used for certain temporary structures. All temporary structures will be confined to powerhouse site, and will be removed once the construction works are completed. Proposed Headrace Canal path goes parallel to the penstock of Adavikanda project Plate 2.3: Section of the proposed headrace canal path 32

43 Proposed Headrace Canal path Plate 2.4: Section of the proposed headrace canal path located in a home garden Post project construction activities Post construction works predominantly include removal of temporary structures, removal of construction waste and other unwanted materials, filling up of ditches/pits made due to various construction works and machine operation, and landscaping at powerhouse site. Sites disturbed by construction activities due to unavoidable circumstances will be rehabilitated by planting tree species native to the area Details of trees to be removed No trees of significance will be removed during the construction of project components. As seedlings and saplings of common trees and shrubs will be disturbed, providing a complete account of their details is not relevant for this project. Approximately 60 tea bushes need to be removed along penstock path Phased development activities and time schedule Project will be implemented in a single phase. The anticipated duration of the construction phase is 24 months. Phased development activities and time schedule is provided in Annexure 2-G. 33

44 Infrastructure facilities Under the proposed project, about 100m section of the existing unpaved path (towards weir) will be developed. This will be a social and economic benefit to the local community as they will be able to use the developed road for their daily activities. The project will further support a small scale drinking water scheme for the families (about 5 families) who are likely to be affected by proposed project activities. This scheme will help uplift their living standards (relevant documents are attached under Annexure 2-H) Work force The proposed project will generate numerous employment opportunities, boosting the local economy. The construction phase will involve about 30 unskilled laborers and 15 skilled laborers while the operational phase will employ about 6 unskilled, and 4 skilled personal. In all cases, locals will be hired and given the priority Project funding and costs The project is estimated to cost LKR 136,250, Estimated budget of the entire project with a breakdown of costs for each component is provided in Table 2.2. Table 2.2: Estimated budget of the Binathura Ela mini-hydro power project Description BOQ amount (Rs) Preliminaries 6,500, Access road 2,250, Design cost 1,500, Weir and intake 6,000, Headrace canal 6,000, Forebay and spillway 8,000, Penstock 22,000, Electromechanical plant 40,000, Powerhouse 10,000, Tailrace 1,000, Switchyard 6,000, Interconnection and TX line 6,000, Site administration expenses 18,000, Project cost 133,250, IDC 3,000, Total project cost 136,250,

45 The project cost is proposed to be financed by a mix of Ordinary Shares (40% of the total budget) and Long Term Debt (60% of the total budget). The total Equity requirement for the project will be arranged by the promoters and the Debt component is to be sourced under the REREAD credit scheme available for hydropower projects with the local Bank and other participatory credit institutions Other mini-hydro projects in the area There are four other mini-hydro developments along Kuru Ganga. These are Batathota (2.0MW), Adavikanda (6.5MW), Warnagala and Murukanda proposed MH project. No other MH developments exist on Binathura Ela upstream above the weir. Components of Adavikanda MH project overlap with the proposed project. 35

46 Binathura Ela Proposed MHP Figure 2.13: Other existing and proposed mini-hydro power projects on Kuru Ganga 36

47 2.2. Evaluation of Alternatives Comparison against No action alternative The proposed mini-hydro power project is expected to generate 2.1GWh annually. Taking both project lifespan and production cost of common non-renewable energy options into account, the GOSL will be able to gain substantial foreign exchange savings by commissioning the proposed power plant. Even against the least cost alternative of using coal, the annual savings are approximately Rs million/year. This can help Sri Lanka to reduce its overall fossil fuel consumption, thus improving energy security. As the proposed project will have zero CO 2 emissions, the estimated emission reductions through implementing the project will be tons CO 2 /year. Further, the electricity produced by the project will displace electricity produced by fossil fuel power plants on the grid, leading to lower overall emissions of SO x and NO x from the grid as a whole. In addition, the proposed project will also generate numerous employment opportunities during construction and operation phases, boosting the local economy. As discussed in subsequent sections of this IEE report, the proposed project has comparatively low impacts on the bio-physical and social environment. Most of these negative impacts could be effectively mitigated. As such, the decision for No Action will forego all these economic, environmental and social benefits of the proposed project, and therefore could not be recommended Alternative sites As MHPs require a combination of unique factors (geomorphological, topographical and hydrological), identifying alternative sites to meet all these key factors is rather impractical. The Binathura Ela MHP project is designed to have a gross head of 70m which is sufficient to produce 2.1GWh of renewable energy each year. Several possible alternative sites suitable for MHPs in the area have already been developed or proposed to be developed. In this context, how to optimize the design to reap maximum benefits while causing minimal disturbances to the bio-physical and social environment is the issue that should be given a greater priority in designing the project. The present site selection can be justified on following grounds; 37

48 Potential alternative sites suitable for MHPs in the area have already been developed or proposed to be developed. Present site is selected to reduce the cumulative impacts of MHPs on the overall environment. The entire site including the access road to the weir runs through private lands and most of the lands have been purchased and clearance required from Land reform Authority has been obtained under Adavikanda MPH. Hence, new land requirement and utilization is minimal. Location of project components has been determined after consulting landowners. The diversion point/weir location has been determined to minimize the upstream flooding Alternative design, technology and construction techniques The box-type headrace canal can be replaced with a penstock pipe. However, this option is not economically feasible as it will significantly elevate the project cost. Although an open headrace canal would be the cheaper option, a closed (box type) headrace canal has been proposed for maximum environmental protection. Alternatively, steel penstock pipes can be replaced by High-Density PVC pipes as a low cost option. However, if HD PVC pipes are to be used, ideally, they need to be buried underground. This will cause substantial damages to the riverine habitat and likely to cause soil erosion during construction phase. For optimization of penstock, 3 configurations of penstock pipes were considered. For each configuration, the penstock design was done using a spreadsheet model. Head loss per configuration was calculated and the effect on energy generation due to head loss under each scenario was determined. Optimization was done on the basis of incremental cost benefit analysis. As a result, penstock diameter was selected with a range of 800 mm to 500 mm. 38

49 CHAPTER 03: DESCRIPTION OF THE EXISTING ENVIRONMENT 3.1. Physical Environment Topography The proposed mini hydropower project will be constructed in the south-western corner of the main mountainous block of Sri Lanka, which is called the Central Highlands of Sri Lanka. The project area is situated at the border of the Peak Wilderness Sanctuary, thus possessing a great diversity of geomorphologic features within a comparatively small surface coverage. A. Weir site and stream topography The planned diversion weir of the project will be built across Binathura Ela with a small catchment that drains from ca. 700m to 297 m altitudes above the MSL. At the proposed diversion site, Binathura Ela tributary runs over a wide valley with a bottom-flatted shaped cross section, having a fairly shallow river bottom (Plate 3.1). The upstream catchment above the weir, which drains to the proposed pond, possesses a rugged topography consisting of NW-SE oriented ridges and valleys (please see the Figure 2.7 for contour plan at the weir). Plate 3.1: General topography and geomorphological features at the weir site 39

50 The topography is parallel to the general strike direction of the basement rocks of this area This small upstream tributary flows to the main stream of Kuru Ganga and connects at ca. 240 m contour line. Average width of Binathura Ela at the weir site is approximately 20m. Left bank is about 1.2m high and the area beyond left bank is sloping towards SE. left bank is 3-5m high and the area beyond is sloping towards NW. Scattered boulders can be observed at the weir site. Top soil layer of the stream bank consist of Browninh-black silty sand soil. Another small tributary called Baru ela converge Binathura ela just downstream of the proposed weir location. B. Ponding Area Flow of the river at the weir site and ponding area was found to be turbulent. A large extent of the tributary drains over a forest patch where erosion is close to natural levels. Consequently, stream water contains low amount of suspended particles as observed during the field studies. The sand/gravel river bed is protected by a deposit of boulders ranging from 0.5 m to 5-6 m (Plate 3.1). Within the tributary, smaller boulders are more rounded than larger ones. Some of the boulders within the ponding area give the impression to be movable; hence they should be mapped, then removed or chemically blasted during the construction. Because of agitated nature of river flow and presence of low amounts of suspended loads, a minimum yield of siltation would be expected within the ponding area. In the ponding area of this project, the left bank of the tributary is very gentle with an angle less than 10 degrees trending to NW direction. The left bank at the weir site and ponding area is almost flat and extended to a floodplain. Furthermore, lands on both stream banks are mantled with a thin overburden. Hence, slope failures will be a minimum in the vicinity of the ponding area after inundation. The toe of the slope at left bank is characterized by a several bedrock exposures. Also, a large number of huge boulders rest on the toe at the left bank. Hence, stream erosion on the left bank would be minimal after the inundation. In contrast, no fresh or weathered bedrock has been exposed along the toe of the left bank within the ponding area. Instead, alluvial sediments are piled up and relatively a less density of boulder distribution is visible along the toe of the left bank (Plates 2.1 and 3.1). This geological setting implies that the left bank will be more vulnerable to stream erosion after inundation. Therefore, a strip of boulders and rock fragments can be laid along the toe of the left bank in order to minimize bank erosion. 40

51 C. Headrace canal The proposed headrace channel will be constructed on the left bank of the weir with a total length of about 280 m. The channel is aligned along the E-W direction lying on a nearly flat terrain (Plate 3.2). The channel first follows on bare land, then along the boundary of a gravel road and at the end along the boundary of a concrete road. No mass movements or slope failures are prone along the headrace channel path. Proposed Headrace canal path Plate 3.2: Part of the headrace canal located on previously acquired land D. Forebay tank The proposed fore bay is located at about 260 m elevation. The forebay is located on a relatively flat terrain (10 o slope towards NW) of an abandoned crop land (Plate 3.3). Top soil of the site consists of brownish silty sand soil. No landslide or slope failures are characterized in this location. 41

52 Proposed Forebay tank site Plate 3.3: Location of the forebay site E. Penstock Path The penstock will be aligned along the slope plane of W directed hill slope. The length of the penstock line is approximately 980 m running over homestead/garden. The path is laid over varying terrain with inclines and slopes. However, penstock path is safe in the view of mass movements. Dark brown sand clay soils are the major soil type found along the penstock path. Three small streams underpasses the proposed penstock path. The penstock path will be laid parallel and together with the existing penstock path of Adawikanda mini hydropower project that has already been commissioned (Plate 3.4). The strip of land that has already been acquired for the previous project is cleared and leveled during the earlier constructions. Therefore, in the process of construction of the penstock of the proposed project, large-scale excavations will not be involved and then the effects to the physical environment will be at a minimum. 42

53 Plate 3.4: Section of the penstock path going parallel to the penstock of Adavikanda MHP F. Power House The powerhouse will be located on the left bank of Kuru Ganga and 200 m from the Batadomba road. It will be constructed in a terrain of bowelled shaped landscape. This location is underlain by granite gneiss and covered by an abandoned rubber plantation (Plate 3.5). The land is generally flat, but as it gets closer to the river bank, the terrain tends to slope towards Kuru Ganga at a slope angle of about 15 degrees. Since the proposed location of the power house is closer to the left bank of Kuru Ganga, it should be designed in a way that is not affected by high floods of Kuru Ganga. An open tailrace channel will transport the tailrace water from the powerhouse to the Kuru Ganga. At this location, the river bed is covered by large rock boulders (Plate 3.6) and this natural setting will control the velocity of tailrace water minimizing the bank erosion in the downstream. Boulder sizes range from 0.5 m to 6 m and some are moveable (Plate 3.1). 43

54 Plate 3.5: Propose power house site Plate 3.6: Section of Kuru Ganga at proposed tailrace location 44

55 Figure 3.1: Topography of the project area 45

56 3.1.2: Geology The proposed mini hydropower project will be constructed in the south-western corner of the main mountainous block of Sri Lanka; the Central Highlands. Geologically, the project area belongs to the Highland Complex of Sri Lanka and it is located very close to the boundary between Highland and Wanni Complexes. The Highland Complex is an important crustal unit of Sri Lanka that occupies a central belt trending NE-SW and covers the most of the central hill country and parts of southwest and northeast plains of the island. Within and in the vicinity of the project area, no economically valuable mineral resource has been discovered or being exploited. Hence, the proposed project will have no influence on any mineral-based industry in the region. The rocks in the project area are crystalline and hard with tightly interlocked grain boundaries having very low porosity. In the context of geology, the terrain is highly stable for the proposed constructions. Geologically, the proposed weir site will be built on a terrain of granite gneiss. Strike and dip of the lithological bands in this area do change significantly. The upstream catchment above the weir site is underlain by three main lithological units; granite gneiss (about 50%), Garnetsillimanite-biotite gneiss (about 35%) and charnockitic gneiss (15%) (Figure 3.2). The toe of the slope at left bank is characterized by a several bedrock exposures. Also, a large number of huge boulders rest on the toe at the left bank. Hence, stream erosion on the left bank would be minimal after the inundation. In contrast, no fresh or weathered bedrock has been exposed along the toe of the left bank within the ponding area. Instead, alluvial sediments are piled up and relatively a less density of boulder distribution is visible along the toe of the left bank. This geological setting implies that the left bank will be more vulnerable to stream erosion after inundation. Geologically, the headrace channel will also run over a granite terrain with a regolith thickness of 1-2m. No mass movements or slope failures are prone along the headrace channel path. The forebay is located on a on a granite gneiss lithology with a thin overburden of up to 2m. No landslide or slope failures are characterized in this relatively flat land. Penstock path is also safe in the view of mass movements. Power house location is underlain by granite gneiss. At this location, the river bed is covered by large rock boulders and this natural setting will control the velocity of tailrace water minimizing the bank erosion in the downstream. 46

57 Figure 3.2: Map showing the geology of the project area. Depicted lithology is traced from the Geological maps (sheets 16 and 17) published by the Geological Survey and Mines Bureau (GSMB) 47

58 Landslide-prone and erodible areas The National Building Research Organization (NBRO) has published a landslide hazard prone map for the entire Rathnapura district which includes the project area. Considering the susceptibility to landslides, the land is categorized into four groups as; (i) landslides are not likely to occur (ii) landslides can be expected (iii) modest level of landslide hazard and (iv) andslides are most likely to occur. In the project area, about 90% of the upstream catchment lies within the zones of (i) and (ii), thereby showing a low level of landslide hazard (Figure 3.3). The locations of proposed diversion weir, the pond, headrace path and penstock path also belong to zones (i) and (ii) indicating a low landslide hazard. However, the align crossing some areas with modest level of landslide hazards. The detailed landslide hazard investigation report prepared by the NBRO for the proposed project site is appended in Annexure 3-A. Figure 3.3: Landslide risk in the project area (Source: 48

59 Land use pattern of the project area The proposed project components span over both state and private lands. Private lands predominantly include agricultural lands and some home gardens. Most of the lands have been purchased and clearance required from Land Reform Authority has been obtained under Adavikanda MPH by Alternate Power System (Pvt.) Ltd. The project area possesses a well-developed concreted road network. Four major types of land uses could be recognized over entire project area including the catchment; forest, agricultural lands (rubber and tea mainly), home gardens and scrublands. The upstream catchment of the weir site is covered by a thick forest (about 60%) and homesteads/garden (about 40 %). Right and left banks of the upstream tributary from weir site to contour line of 320m are mainly composed of homesteads/gardens whereas the area further upstream is completely covered by forest. Both river banks of Binathura Ela is mainly composed of a narrow belt of riverine vegetation (river bank reservation) bordered by home gardens/agricultural lands. The headrace channel first follows on bare land, then along the boundary of a gravel road and at the end along the boundary of a concrete road. The forebay is located on a flat terrain of an abandoned crop land. The powerhouse location is also an abandoned rubber and which has become a scrub. The general land use in the project area is depicted in Figure 3.4. Physical addresses of properties that fall within the study area is provided below. Name Address GN Division 1 L.Sirisena Witharampanguwa, Erathna, Kuruwita Lassekanda 2 J.W. Kapila Ranjith Witharampanguwa, Yaya, Erathna, Kuruwita Lassekanda 3 J.W. Thushara Jayalath Witharampanguwa, Yaya, Erathna, Kuruwita Lassekanda 4 K.H. Seneris Witharampanguwa, Yaya, Erathna, Kuruwita Lassekanda 5 T.P. Agoris No. 175, Witharampanguwa, Erathna Lassekanda 6 G.H. Wilbert Witharampanguwa, Erathna, Kuruwita Lassekanda 7 H.G. Dhanawathi Witharampanguwa, Yaya, Erathna, Kuruwita Lassekanda 8 K.I. Karamanis Witharampanguwa, Yaya, Erathna, Kuruwita Lassekanda 9 Premalatha Sudarshani Lassekanda, Erathna, Kuruwita Lassekanda 10 Rohitha Weerarathne Witharampanguwa, Yaya, Erathna, Kuruwita Lassekanda 11 K.P. Sirisena Witharampanguwa, Yaya, Erathna, Kuruwita Lassekanda 49

60 Figure 3.4: General land-use pattern of the project area 50

61 Kuru Ganga Transmission line path Concreted Access road Location of Houses Binathura Ela Figure 3.5: Locations of households and other infrastructure 51

62 Hydrology A. Drainage and the effective catchment area Binathura Ela MHP has a catchment area of 7.14 km2 extending from 295 meters above AMSL to 1500m AMSL receiving an annual average rainfall of 5152 mm. The catchment area extends up to Erathna with the major portion lying within the Peak Wilderness Sanctuary. The longest length of the main stream is 3.10 km approximately and it has a slope exceeding 20% and therefore the catchment is very steep. The land use in the catchment consists of scrub jungle, home gardens and bare land and it is hydrologically favorable for conservation of water. Figure 3.6 shows the catchment boundary. Figure 3.6: Effective catchment area for Binathura Ela mini-hydro project B. Rainfall pattern There are no rain gauge stations or stream flow measurement stations or any other hydrological instrumentation in the catchment area. The only known rain gauge in Kuru Ganga catchment is at Keragala located on the right bank of Kuru Ganga and below Erathna and it has a long term rainfall data. The daily rainfall records from 1983 to 2012 for last 29 years were used for hydrological studies. 52

63 annual rainfall in mm Figure 3.7 shows the annual rainfall variation over the period of 1935 to Figure 3.6 shows the long term average monthly rainfall variation during an average year. These figures suggest that annual rainfall is consistent and no downward trend is visible. Rainfall during the SW monsoon is more predominant and the lowest rainfall occurs in January (Figure 3.8). Accordingly, the average annual rainfall is determined to be 5152 mm. y = x From 1935 to 2012 Figure 3.7: Annual rainfall variation (Keeragala station: 1935 to 2012) Figure 3.8: Average monthly rainfall distribution (Keeragala Station) C. Flow details A detailed hydrological study was conducted covering the period 1983 to 2012 with an evaluation on the observed rainfall and stream flow. The detailed hydrological report 53

64 prepared by a qualified hydrologist for the proposed project is appended in Annexure 3-B. Monthly runoff volumes at Binathura Ela are presented in Figure 3.9. According to the results of the hydrological modeling simulations used, highest monthly runoff was observed in the month of June, which is 3.17m 3 /s. Cumulative average runoff during NE monsoon was estimated to be 9.99 m 3 /s while the same parameter for the SW monsoon period was estimated as m 3 /s. Figure 3.9: Average monthly flows at the Binathura Ela MHP weir site Using the monthly flow volumes, both 50 % and 75%, probable flows were estimated from the seasonal flow volumes. Table 3.1 shows the ordinates of the flow duration curves. Table 3.1: Ordinates of the flow duration curves Range % Discharge m 3 /s P(x)=50% P(x)=75%

65 The flow duration curves prepared using the generated daily flow series under 50 % and 75% probabilities are presented in Figure 3.10 and 3.11 respectively. It could be concluded that 1.27m 3 /sec is conservative figure as the Average Daily Flow of the catchment. Figure 3.10: Flow duration curve for the average flow regime P(x) = 50% Figure 3.11: Flow duration curve for the average flow regime P(x) = 75% D. Low flow analysis Table 09 shows the annual daily minimum flow rates obtained from 29 years of generated data. From Table 9 it can be seen that lowest estimated flow during 29 years is 8.50 lit/sec. 55

66 Table 3.2: Annual minimum flow rates at weir site Year Min. flow Year Min. flow lit/sec lit/sec 1983/ / / / / / / / / / / / / / / / / / / / / / / / / / / Mean / Std,.Dev / Skew E. Peak Flood Discharge A flood study was done for the catchment above the diversion site by the application of Rational formula. The maximum length of the stream up to the diversion site is 3.10 km and this was estimated from topographical maps. The catchment drops from 1500 m MSL to 300 m MSL at the weir site and therefore the slope of the catchment exceeds 20 %. The area belongs to the hydrological zone No.4 as defined by the Irrigation Department (ID) guide lines and rainfall intensities for different return periods were obtained from the Depth Duration Frequency curves (DDF) of the Irrigation Department. The time of concentration (Tc) was estimated at 40.0 minutes assuming a velocity of 2.0 m/sec. According to the depth duration curve for this hydrological zone IV, twenty-four-hour rainstorm for 100 year return period is 400.0mm and observed maximum rainfall at Ratnapura during 2003 flood was only mm. Therefore the DDF curve of the ID will be used to design the rain storm without any adjustments. The flood peaks corresponding to 100 years return period was estimated at 164.0m 3 /s. The corresponding figures for 50 year and 25 year return periods are 158.6m 3 /s and 140.2m 3 /s. No formal records exist on heights flood experiences at the site. According to locals, flood levels can exceed up to 3.0m at the weir site. Minor floods occur every year during peak 56

67 monsoon period. As the proposed weir will act as a barrier for the flow of water, it can induce short term flooding in the area above, especially during peak rainy season. However, due to the design and height of the weir, excess water can easily flow over the weir. F. Water Quality Water quality was evaluated using physically observable parameters such as colour, odor, clarity, suspended partials etc. Accordingly, waters of Binathura Ela are clear, with low sediment levels. However, chemical use in agricultural lands can contaminate these waters. Examining chemical properties of the water is beyond the scope of this IEE. G. Summary of the Hydrological analysis Average annual rainfall at Keeragala rain gauge ( ) for 29 years: 5152 mm Average annual pan evaporation for 20 years ( : Ratnapura gauge): 1192 mm Annual average daily flow rate from 29 years of generated river flows: m 3 /s Runoff Rainfall ratio based on generated stream flow: %. Maximum average daily flow rate from the 29 years of Generated data: 5.54m 3 /s Minimum daily flow rates from average flow regime: 8.50 lit/sec Flood peak corresponding to 100 year return period: 164.0m 3 /s 3.2. Biological Environment Proposed project is located in Kuruwita Division of ratnapura District, which falls in the Wet Zone of Sri Lanka. Hence, the prevailing climatic condition in the area is tropical wet climate with high rainfall and tropical high temperature. The area predominantly falls in to WL1a agro-ecological zone of the country (low-country wet zone). The area receives high annual rainfall of over 3300 mm with highest rainfall observed in May-June where South-West monsoon is active and in October-November where inter monsoonal rains prevail. The average maximum ranges from 27 to 33 0 C. The highest values are being recorded during the period of late February to early May. The average minimum temperature varies from 18 to 22 0 C with lowest values being generally observed during the period of December to February. The day time relative humidity ranges from 55 to 85% whereas nighttime values ranges from 75 to 85 percent (Punyawardene, 2008). In the context of biological diversity, the proposed project mainly comes under floristic regions IX (Foothills of Adam's Peak and Ambagamuwa) and VIII (Wet Zone Freshwater Bodies). 57

68 Assessment of Floral Diversity A. Methodology for the survey of flora Identification of key habitats and floral diversity is crucial in evaluating potential ecological impacts of the proposed project activities. For this purpose, the study site was divided into seven segments as described below; 1. Weir, intake structure and upstream: The area identified for the construction of the weir and the area that will be inundated due to construction of the weir up to 50 m upstream of the location of the weir (including both right and left bank) and the area identified for the construction intake structure) 2. Headrace channel: A 5 m wide belt on either side of the proposed penstock (it runs along near the left bank of the Binathula Ela) 3. Forebay (proposed to build newly planted small patch of tea land) 4. Penstock: A 5 m wide belt on either side of the proposed penstock (it runs very near along the existing penstock of the Adavikanda Mini Hydropower Project) 5. The area identified for construction of the powerhouse, tail race channel, and switch yard. 6. Downstream up to 50 m (including both left and right bank) 7. Access road to the power house In order to identify key habitats and vegetation in and around the project area, a reconnaissance survey was performed within each segment. Floral species exist in the project area were inventoried through a rapid survey/assessment method. All plant species and different habitats present within each segment were examined using the line transect survey method according to the guide line given by Table 1 of TOR (Annexure 3-E). In addition, any noteworthy vegetation on the proposed site were carefully observed and recorded using a direct record method. All the species observed were recorded with respect to its location and the results were pooled according to the habitat. In addition to the species, the types of habitats were also recorded. Species identification was based on the latest literature published on the fauna and flora of Sri Lanka (Ashton et al., 1997; Dassanayake and Fosberg, : Dassanayake, Fosberg, and Clayton, ; Dassanayake and Clayton, ; Dassanayake, Clayton, and Shaffer-Feher, 2006; de Vlas, 2008; de Vlas, 2014). Nomenclature of the species is presented and the conservation status of the species was determined mainly 58

69 according to The National Red List 2012 of Sri Lanka and using latest published records such as Senaratna (2001). B. Main habitats types Biogeographically, the proposed project area comes under floristic regions IX (Foothills of Adam's Peak and Ambagamuwa) and VIII (Wet Zone Freshwater Bodies) and tropical wet evergreen forest is the typical forest formation present in the area. Most of the lands in the proposed project area has been subjected to heavy human influence and cleared for human settlements and agriculture. There is a strip of disturbed forest located along the stream banks of Binathura Ela and Kuru Ganga that somewhat resembles the typical forest formation in the area. Therefore, stream and streamside vegetation are the main existing natural habitats in the proposed project area. Except riverine vegetation, small patches of scrub vegetation seen on the area can also be considered as a natural habitat type in the project area. Tea plantations and home gardens are the abundant non-natural habitats present in the area. All project components are located in the left bank of the river. Riverine vegetation is the prominent habitat type present near the weir site, ponding area, and intake structure. First 200m of the Headrace channel runs through the riverine vegetation and then it follows the same route of existing Penstock path of Adavikanda MHP project that runs through the scrublands and tea cultivations. Forebay will be constructed on a newly cultivated tea land. The steel penstock leading to the powerhouse passes through tea cultivation, home gardens and scrub vegetation. The powerhouse will be located in small grassy area locate on the left bank of Kuru Ganga. The water after power generation will be released back to Kuru Ganga through a short tailrace. In this area water flows in a moderate speed and shallow water pools and substratum can be seen. C. The floral diversity A total of 211 flowering plant species were recorded from the study site. Their occurrence in different study segments are shown in Table 1 of Annexure 3-C while their vernacular names, habit, origin, conservation status and uses are provided in Table 2 of the Annexure 3-C. The plant species recorded included 91 trees, 51 shrubs, 41 herbs, 24 climbers including lianas and 3 species of grasses and one epiphyte. Recorded flowering plants included 126 native species (60%) with 38 endemic species (18%). The study site is locates in the south-west region of the country where considerably 59

70 high number of endemic plant species can be seen. Due to the high human influence on the environment, numerous alien species are found in the study area. There were 80 introduced species (exotics) (38%) recorded in the study site (origin of 5 species is unknown). Introduced species includes 9 invasive alien species (IAS) and 25 naturalized exotics. Thirty one (31) nationally threatened plant species and 16 globally threatened plant species were recorded from the site. It includes 2 Nationally Endangered (EN), 11 Nationally Near- Threaten (NT), and 18 Nationally Vulnerable (VU) species (Table 3.3). However, all the recorded endemic and threatened species within the study site are not unique or restricted to the project area. They are found in similar habitats in the low country wet zone. Table 3.3: Endemic and nationally threatened flora recorded in the project area Family Species Sinhala Name TS NCS Acanthaceae Strobilanthes sp. Nelu E Anacardiaceae Campnosperma zeylanicum Aridda E Anacardiaceae Mangifera zeylanica Atamba E Anacardiaceae Semicarpus gardneri Badulla E Anisophyllaceae Anisophyllea cinnamomoides Weli-Piyana E NT Annonaceae Uvaria semecarpifolia Kara Bambara E Apocynaceae Chonemorpha fragrans Bulu-Wal-anguna N VU Apocynaceae Pagiantha dichotoma Divi-Kaduru N Apocynaceae Walidda antidysenterica Wal-Idda E Araceae Cryptocoryne sp. E Araliaceae Schefflera emarginata Heen iththe wel E VU Arecaceae Calamus digitatus Kukula-wel E VU Arecaceae Oncosperma fasciculatum Katu-Kithul E VU Asperagaceae Dracaena thwaitesii Wedikoka Gas N NT Balsaminaceae Impatiens flaccida Kudalu-mal N VU Burseraceae Canarium zeylanicum Kekuna E VU Calophyllaceae Mesua thwaitesii Diya-Na E Celastraceae Salacia reticulata Kotala-himbutu N EN Centroplacaceae Bhesa ceylanica Palang E Clusiaceae Garcinia echinocarpa Madol N VU Clusiaceae Garcinia quaesita Rat Gorka E Connaraceae Connarus championii Wel-Radaliya E NT Dilleniaceae Schumacheria castaneaefolia Kekiri-Wara E Dipterocarpaceae Dipterocarpus zeylanicus Hora E NT Dipterocarpaceae Stemonoporus canaliculatus Mandora E EN Elaeocarpaceae Elaeocarpus subvillosus Gal-Weralu E NT 60

71 Euphorbiaceae Agrostistachys hookeri Maha Beru E Fabaceae Adenanthera bicolor Mas-Mora E NT Gentianaceae Fagraea ceilanica Etamburu N NT Lamiaceae Vitex altissima Milla N NT Lauraceae Cinnamomum dubium Sewl-kurundu E VU Lauraceae Cinnamomum zeylanicum Kurundu E VU Lauraceae Litsea longifolia Rat-Keliya E Malvaceae Cullenia rosayroana Katuboda E Melastomataceae Lijndenia capitellata Pini-baru E VU Melastomataceae Memecylon rivulare Pinibaru E VU Melastomataceae Osbeckia octandra Heen-bovitiya E Moraceae Artocarpus nobilis Bedi-Del E Moraceae Ficus diversiformis E Myristicaceae Horsfieldia iryaghedhi Ruk E VU Myrtaceae Syzygium neesianum Panu kera E Pandanaceae Freycinetia walkeri Viyakeyya E NT Phyllanthaceae Aporusa lanceolata Hin-Kebella E Poaceae Ochlandra stridula Bata E Rhamnaceae Zizyphus rugosa Maha-Eraminia N NT Rhizophoraceae Carallia brachiata Dawata N NT Rubiaceae Exallage auricularia Gate kola N VU Sapotaceae Madhuca neriifolia Gan-Mi N VU Sapotaceae Palaquium grande Kiripedda E VU Thymelaeaceae Gyrinops walla Walla patta N VU Zingiberaceae Amomum echinocarpum Bu-Kiriya E VU Zingiberaceae Elettaria cardamomum Caradamungu N VU TS (Taxonomic Status): N Native, E Endemic NCS (National Conservation Status): NT- Near Threaten, VU Vulnerable, EN Endangered Assessment of Faunal Diversity A. Methodology for the survey of fauna Faunal survey was conducted along the same line transects used for floral survey. All faunal species encountered along the line transect and to either side were recorded (Visual Encounter Survey). For the survey of mammals, herpetofauna and insects (butterflies and Odonates), 10m wide belt transects were used. For the survey of fish, random sampling was used in more or less uniform areas of the stream, while pre-identified significant habitat locations were especially sampled. Indirect observations such as calls, foot prints, pellets, droppings, feathers, skins and tracks were also used in inventorying mammals, birds and herpetofauna. 61

72 Observed faunal species during the field survey were verified using published descriptions by Harrison (1999), Philips (1935), Kotagama (2005), Kotagama and Goonathilake (2014), Das and De Silva (2005), Bedjanic et al., (2006), and de Silva Wijeyeratne (2006). The conservation status of the species was verified from the National Red List of Threatened Fauna and Flora of Sri Lanka (2012). Since the faunal survey was subjected to time constraints, there s a high probability that numerous species inhabit the area not being recorded. Therefore, secondary information such as personal communications with villagers and site managers were also used. In addition, information available in published literature and unpublished checklists/records were also used for comparison and validation purposes. B. Faunal diversity in key habitats A total of 167 species were recorded during the field survey. As indicated in Table 3.4, this included 19 mammals, 64 birds, 6 amphibian, 24 reptiles, 11 fishes, and 43 insect species (butterflies and dragonflies). Out of the total 167 faunal species recorded, 136 were native to the country (81%) while 30 species being listed as endemic (15%). There were 28 nationally threatened faunal species recorded in the study area which include 7 mammals, 3 birds, 2 amphibians, 1 reptile species, 5 fish and10 insect species (butterflies and dragonflies). As the project site is located in a biodiversity rich bioclimatic region of the country, high faunal diversity can be anticipated. However, larger percent of the project area is already subjected to human influences (such as agriculture and settlements) and therefore, comparatively less faunal diversity was observed in the study. Table 3.4: Summary of faunal assemblage in the project area Taxonomic group Total no. of species Endemic species Native species National Conservation Status CR EN NT VU Mammals Birds Reptiles Amphibians Fishes Insects: Butterflies Dragonflies Total CR: Critically endangered, EN: Endangered, NT: Near threatened, VU: Vulnerable 62

73 Table 3.5 provides a list of endemic and threatened faunal species recorded in the project area. A comprehensive list of fauna recorded during the field survey is provided in Annexure 3-D. Table 3.5: Endemic and threatened fauna recorded in the project area Mammals Family Scientific Name Common Name TS CS Manidae Manis crassicaudata Pangolin N NT Cercopithecidae Macaca sinica Sri Lanka Toque Monkey E Semnopithecus vetulus Purple-faced Leaf Monkey E EN Lorisidae Loris tardigradus Sri Lanka Red Slender Loris E VU Mustelidae Lutra lutra Otter N VU Cervidae Rusa unicolor Sambur N NT Muntiacus muntjak Barking Deer N NT Tragulidae Moschiola kathygre Sri Lanka Pigmy Mouse-deer E VU Birds Familly Scientific Name Common Name TS CS Phasianidae Gallus lafayetii Sri Lanka Junglefowl E Galloperdix bicalcarata Sri Lanka Spurfowl E NT Ramphastidae Magalaima flavifrons Sri Lanka Yellow fronted Barbet E Bucerotidae Ocyceros gingalensis Sri Lanka Grey Hornbill E Psittacidae Loriculus beryllinus Sri Lanka Hanging Parakeet E Psittacula Calthropae Sri Lanka Emerald Collard Parakeet E NT Dicruidae Dicrurus lophorhinus Crested Drongo E VU Timalidae Pellorneum fuscocapillum Sri Lanka Brown-capped Babbler E Pomatorhinus melanurus Sri Lanka Scimitar Babbler E Reptiles Familly Scientific Name Common Name TS CS Agamidae Otocryptis weigmanni Sri Lankan Kangaroo Lizard E Natricidae Xenochrophis asperrimus Checkered Keelback E Colubridae Boiga forsteni Forsten's cat snake N NT Oligodon sublineatus Dumerul's kukri snake E Viperidae Trimeresurus trigonocephalus Green pit Viper E Amphibians Familly Scientific Name Common Name TS CS Ranidae Hylarana gracilis Sri Lanka Wood Frog E Hylarana temporalis Bronzed Frog E NT Nyctibatrachidae Lankanectes corrugatus Corrugated Water Frog E VU Fresh Water Fish Familly Scientific Name Common Name TS CS Cyprinidae Garra ceylonensis Stone Sucker E VU Dawkinsia singhala Filamented Barb E Tor khudree Mahseer N NT Balitoridae Schistura notostigma Sri Lanka Banded Mountain Loach E NT 63

74 Aplocheilidae Aplocheilus werneri Werner's Killfish E EN Belontiidae Belontia signata Combtail E NT Dragonflies Familly Scientific Name Common Name TS CS Cholorocyphidae Libellago finalis Ultima Gem E VU Euphaeidae Euphaea splendens Shining Gossamerwing E NT Ceriagrion cerinorubellum Painted Waxtail N VU Plastystictidae Drepanosticta nietneri Nietner's Shadowdamsel E CR Protoneuridae Elattoneura centralis Dark-glittering Threadtail E VU Libellulidae Orthetrum chrysis Spine-tufted Skimmer N VU Orthetrum pruinosum Pink Skimmer N NT Trithemis festiva Indigo Dropwing N VU Butterflies Familly Scientific Name Common Name TS CS Papilionidae Papilio helenus Red Helen N VU Nymphalidae Idea iasonia Sri Lanka Tree Nymph E VU TS (Taxonomic Status): N Native, E Endemic NCS (National Conservation Status): NT- Near Threaten, VU Vulnerable, EN Endangered Forest and streamside habitats Two terrestrial natural habitat types are affected by project activities. These include (1) the lowland tropical wet zone forest habitats resembled by riverside vegetation and (2) aquatic habitats. These 2 natural habitats have a good faunal diversity, and represent the typical faunal assemblage found under wet zone lowland geo-climatic conditions. Most mammal species recorded are found in these forest/riverine habitats. Among the threatened and endemic mammals recorded in the area (Table 3.5), Sri Lanka Red Slender Loris is of special interest as it is classified as endangered. However, the species was not encountered during field studies and the listing is based on indirect information and literature. Species such as Sri Lanka Toque Monkey and Purple-faced Leaf Monkey are found in both forested habitats as well as in home gardens. However, these species recorded are not unique or restricted to the project area and found elsewhere in wet zone under similar habitat conditions. Besides, only the weir and part of the penstock path are located in forested and riverine habitats, and therefore will cause negligible impacts to natural habitats. Any impact of significance will be restricted to construction phase of the project. Freshwater stream habitats These are a major type of natural habitats that will be directly affected by the project due to construction of weir at Binathura Ela. The two directly affected freshwater stream habitats; Binathura Ela and Kuru Ganga. Although the river morphology and flow characteristics seem 64

75 to vary between the two systems, both appeared to have similar fresh water fish assemblage. Eleven and ten fish species were recorded from Binathura Ela and Kuru Ganga freshwater stream habitats respectively (Table 3.6). Table 3.6: Fish species recorded in Binathura Ela and Kuru Ganga systems Family Scientific Name Common Name TS CS Binathura Ela Kuru Ganga Anguilidae Anguilla bicolor Level finned Eel N * * Cyprinidae Devario malabaricus Giant Danio N * * Garra ceylonensis Stone Sucker E VU * * Dawkinsia singhala Filamented Barb E * * Rasbora dandiya Broad line striped Rasbora N * * Tor khudree Mahseer N NT * * Balitoridae Schistura notostigma Sri Lanka Banded Mountain Loach E NT * * Aplocheilidae Aplocheilus werneri Werner's Killfish E EN * Belontiidae Belontia signata Combtail E NT * * Mastacembelidae Mastacembelus armetus Marbled Spiny Eel N * * Gobiidae Awaous melanocephalus Scribbled Goby N * * TS: Taxonomic status CS: Conservation Status C. Animal movement paths There were no permanent animal movement pathways observed in the project area. Some fish species such as Anguilla bicolor and Garra ceylonensis are known to migrate upstream during different times of the year Social Environment Project background The proposed site is located in Thalagahalanda in the Kuruwita Divisional Secretariat Division of the Ratnapura District. The proposed power house can be accessed by motoring along Colombo - Kuruwita route (78 km) and turning left at Kuruwita to proceed along Kuruwita - Erathna to reach the powerhouse location. The components of the 700 kw proposed mini-hydro power project span over Lassekanda GN division in Kuruwita Pradeshiya Sabha area, Kuruwita D.S. Division, in Ratnapura District, Sabaragamuwa Province. 65

76 The proposed project components span over both State and Private Lands (Figure 2.1 (a) and Figure 2.1 (b)). Various project components, their locations and ownership of the land is summarized in Table 2.1. Total land area utilized by the project is about 0.57 ha. General land use pattern in the project area has been discussed under section and the Figure 3.3 illustrates the land-use pattern of the project area. Table 3.6 summarizes the current land use, ownership and anticipated land use changes of lands where major project components are located. Table 3.6: Current land use, ownership and possible land use changes Project Component Headrace canal Forebay Current land use Land ownership Possible land use changes Riverine vegetation State lands (stream Minor clearances of Existing penstock of reservation) and private riverine vegetation (no Adavikanda project lands owned by Alternate trees over 10cm dbh Abandoned crop land Power Systems (Pvt) Ltd State land with part had been acquired by Alternate Power Systems (Pvt.) Ltd. will be removed) Not significant Penstock Powerhouse Transmission line Existing penstock of Adavikanda project Abandoned cropland (uprooted rubber) Side of a footpath with scrub vegetation State lands and private lands owned by Alternate Power Systems (Pvt) Ltd Private land State lands Minor clearances of vegetation and agricultural crops including tea (no trees over 10cm dbh will be removed) Not significant Minor clearances of vegetation (no trees over 10cm dbh will be removed) Methodology for the socio-economic study In order to get an understanding of the socio-economic setting of the project area, a brief socio-economic survey was undertaken in the Lassekanda GN division. A simple questionnaire was prepared to address the information in TOR. The questionnaire gathered basic demographic information of the local community, infrastructure facilities, usage of local streams and community concerns and perceptions of the proposed Binathura Ela MHP project. All households within a 500m distance from project components were interviewed. Accordingly, a total of 12 households were interviewed with one household declining to participate in the interview (Table 3.7). 66

77 Table 3.7: List of households interviewed Name Address GN Division 1 L.Sirisena Witharampanguwa, Erathna, Kuruwita Lassekanda 2 J.W. Kapila Ranjith Witharampanguwa, Yaya, Erathna, Kuruwita Lassekanda 3 J.W. Thushara Jayalath Witharampanguwa, Yaya, Erathna, Kuruwita Lassekanda 4 K.H. Seneris Witharampanguwa, Yaya, Erathna, Kuruwita Lassekanda 5 T.P. Agoris No. 175, Witharampanguwa, Erathna Lassekanda 6 G.H. Wilbert Witharampanguwa, Erathna, Kuruwita Lassekanda 7 H.G. Dhanawathi Witharampanguwa, Yaya, Erathna, Kuruwita Lassekanda 8 K.I. Karamanis Witharampanguwa, Yaya, Erathna, Kuruwita Lassekanda 9 Premalatha Sudarshani Lassekanda, Erathna, Kuruwita Lassekanda 10 Rohitha Weerarathne Witharampanguwa, Yaya, Erathna, Kuruwita Lassekanda 11 K.P. Sirisena Witharampanguwa, Yaya, Erathna, Kuruwita Lassekanda Socio-economic profile of the project area A. Ethnicity and religion Lassekanda is a rural wet zone village with a mid-size population. All families in the village are Sinhalese. All households interviewed were Sinhalese Buddhists. B. Sources of Income Most of the dwellers are dependent on agriculture for their income and tea is the predominantly grown crop in the project area. Tea was a main source of income for 81% of the households interviewed, hence playing a key role in local economy. Tea leaves are bought at a rate of Rs /kg by factories in the area (rates as of March 2014). Tea smallholders either take their harvest to collection centers or handover to collection vehicles. All households interviewed have tenure rights (Jaya Bhoomi) to their agricultural properties. Average number of individuals per household is 4. Most households have more than one income earners and hence have more than a single income source (Table 3.8). Out of 11 households, 4 households had at least a member employed in the mini hydro power sector. In general, women are unemployed, but contribute to the household economy by assisting agricultural activities and in addition to taking care of usual household tasks. The average monthly household income was less than Rs. 30,000/= for 64% of households interviewed. Home gardens in the project area typically contain other trees of economic importance such as coconut, jack, mango, cocoa and other fruit trees commonly grown in wet zone, as well as cash crops such as banana, pepper, spices, and vegetables grown for domestic consumption 67

78 Table 3.8: Main sources of household income in the project area Source of income % Households Agriculture - tea small holds 81% Government employment 27% Private Mini-hydro power plant worker 36% Private sector - Other 45% Freelance/labour 18% C. Type of households and facilities Most houses in the area are permanent structures made out of clay or cement bricks and having asbestos sheeted or tiled roofs (Table 3.9). All households interviewed have permanent sanitation facilities with majority (90%) having water-seal type facilities while the remainder having pit latrine type. Six houses have concreted access roads while 5 houses having footpaths for access. Three households with concreted access roads owned a fueldriven vehicle (three-wheelers). Table 3.9: Main type of houses in the project area House type % Houses Permanent 84% semi-permanent/incomplete 8% Temporary 8% All households considered for the socioeconomic survey have access to national grid electricity. Therefore, common electronic equipment such as radios and televisions are available in most houses. Energy requirements for cooking are supplied from firewood and kerosene oil. Prunings and removals of Gliricidia and Albizia trees grown on tea plantations as shade trees are commonly used as fuel wood. About 60% of households receive drinking water through a community drinking water supply scheme while the rest rely on spring water/binathura Ela for their potable water needs. Rain water and Binathura Ela are the main water sources for agriculture. Results of this preliminary socio-economic analysis imply that the local community near proposed project site in Witharampanguwa, Lassekanda GN division in general is not in extreme poverty. Instead, this community can be better described as a low to mid income group. Typical low income housing structures found in the project area are indicated in Figure

79 Plate 3.7: A typical low income households in the project area The adult community (over 35 years of age) in the project area has a low education level with majority (62%) have not even completed their education up to Grade 8. However, the younger generation (below 18 years of age) seems to be keener on education with all attending schools continuously. D. Existing Infrastructure Transport: A good road network exists from Kuruwita to Erathna with public transportation (CTB and private buses). Concreted road network exist almost up to the proposed weir site. More remote parts of the village have unpaved gravel roads and footpaths. The area has other basic infrastructure such as a community center, temple and a school. Some of the roads have been concreted and developed under Adavikanda MHP project Use of river water All households covered in the survey are direct users of the waters of Binathura Ela. Three main uses of Binathura Ela were documented during the survey as summarized in Table All households use Binathura Ela for washing and bathing purposes. Five households directly depend on this water source for their drinking water needs. Despite other households being serviced by a community drinking water scheme, some of them also utilize Binathura Ela 69