Xiyaburi dam project poyry july_2012_v_03

1 Xayaburi HPP, Presentation 16 July 2012, Luang Prabang

Xayaburi Run-of-River HPP
Presentation to Government of Lao PDR
and other interested Stakeholders

Monday 16 July 2012, Luang Prabang

Content of Presentation
1. General
2. Introduction of Pöyry
3. State of the art for run-of-river power plants
4. MRC Guidelines
5. Xayaburi HPP and other hydro schemes in the Mekong
6. Prior Consultation Process
7. Roles of Pöyry
8. MRC Guidelines
9. Dam safety
10.Sediments
11.Water Volume in the River
12.Fish Migration
13.Trans-boundary Effects
14.Main project changes recommended and implemented
15.Ongoing investigation works for the detailed design
16.Downstream effects of Run-of-river power plants similar to the Xayaburi Power Plant
17.Video Presentation on Project
18.Conclusions


General
• The general intention of this presentation is to inform the audience on
– particularities of a run-of-river hydropower scheme
– the compliance of the project with the MRC design guidelines
– particular issues which were raised during the Prior Consultation Process
– the concerns related to the issue of sediment transport in the lower reaches of the
Mekong River
– the influence the project might have on the water flow quantities in the lower
reaches of the Mekong River
• It will also be shown what changes the project developer intends to actively
introduce in the project to positively influence the sediment transport process
and the other requirements stipulated in the MRC Design Guidelines.
• The Xayaburi project has been under development since 2007 and the
following studies / reports have been completed by others and used as basis:
– Feasibility study
– Environmental and social impact assessments
– EPC tender documents
– Various Studies on this project and general information available


Presenters of Pöyry

• Knut Sierotzki, Responsible Director for Hydropower Asia and
Russia, 25 years experience in water management and hydropower
globally, since 1991 also working in SE Asia

• René Schmidiger, Senior Project Manager and Dam Expert, 36 years
experience in hydropower projects in all continents, since 1992 also
working in SE Asia

• Dr. Robert Zwahlen, Senior Environmentalist and Biologist, 35 years
experience in environmental impact assessments and management
projects mainly in the tropics, since 1989 also working in SE Asia,
independent expert of World Bank, ADB and other international
organisations on environment


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return on investments.

7
Xayaburi HPP, Presentation 16 July 2012, Luang Prabang

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Major Hydropower projects of Pöyry under execution in 2012

Current Projects No. of MW
Laja I, Chile 35
Taschinas, Switzerland 11
Thurfeld, Switzerland 2
Deriner, Turkey 670
Ermenek, Turkey 300
Tuirial, India 60
Macchu Piccu II, Peru, 100
Quitaracsa, Peru 112
Rucatayo, Chile, 56
Limberg II PSP, Austria 480
Reisseck II PSP, Austria 430
Uma Oya, Sri Lanka 150
Siah Bishe PSP, Iran 1,000
Rheinfelden, Switzerland 116
Tsankov Kamak, Bulgaria 80
Rudbar-Lorestan, Iran 450
Lehen HPP, Austria 20
Xayaburi, Lao PDR 1,470
Ashta, Albania 90
Beyhani 1, Turkey 550
Karlsdorf Gössendorf, Austria 20
Total capacity under execution 6,202


Nam Ngum 2 Hydroelectric Project, Lao PDR
181 m concrete faced rockfill dam and 615 MW hydropower plant (Francis units)

Client
South East Asia Energy Ltd., Bangkok
Thailand

Project Details
Dam height 181 m
Crest length 510 m
Spillway capacity 9,000 m3
Power tunnel 1 x 675 m 3 x 210 m
Gross head 164 m
Rated discharge 422 m3/s
Powerhouse (surface) 3 x 205 MW

Scope of Services
Independent owner’s engineer - feasibility,
tender, detailed design and construction
supervision

Execution Period
2004 – 2011


FREUDENAU HYDRO POWER PLANT, AUSTRIA
Run-of-river power plant with 6 bulb turbines of 30 MW, rated capacity 172 MW

Client
Österreichische Donaukraftwerke AG

Scope of Services
• Prefeasibility study
• Feasibility study
• Engineering design
• Tendering and procurement services
• Design of backwater area in cooperation with
Vienna Metropolitan Administration
• Construction and erection supervision
• Commissioning
Execution Period
1992 – 1998


BIRECIK DAM AND HYDROPOWER PLANT, TURKEY
62.5 m high concrete gravity dam/fill dam with concrete core, 672 MW, 6 Francis turbines

Client
Ministry of Energy and Natural
Resources (DSI), Turkey

Scope of Services
• Feasibility Study
• Final Design
• Construction design
• Site Management
• BOT development
• Operation
Execution Period
1996 – 2001


NATHPA JHAKRI HYDROPOWER SCHEME, INDIA
1500 MW run-of-river power plant in the Himalayan foothills

Client:
Nathpa Jhakri Power Corporation Ltd. (NJPC),
Shimla, India

Scope of Services (1990-2003):
• Preparation and review of technical specifications
• Review of detailed designs and civil construction
drawings
• Establishment of quality control procedures
• Assistance in solving technical problems during
construction
• Settlement of claims
• Advice on construction methodology and
equipment
• General project monitoring and management


Kukule Hydropower Plant, Sri Lanka

Client:
Ceylon Electricity Board
Description:
• Implementation of a 78 MW run-of-
river scheme

Scope of Services (1998-2003):
• Tender documents and drawings
• Assistance in pre-qualification and
tender evaluation
• Civil engineering drawings
• Review of E&M design and
documents
• Supervision of construction, erection
and commissioning


RHEINFELDEN POWER STATION, SWITZERLAND/GERMANY

Client
Kraftübertragungswerke Rheinfelden AG

Project Details
Replacement of power plant from 1895
Owners engineer for design of a 116 MW run-of-
river scheme to replace existing power plan
with 4 bulb turbines a total discharge of
1500 m³/s.

Scope of Services
• Final Design
• Environmental impact assessment and
investigations
• Assistance to client for receiving the
concession from the authorities
• Construction Design and Supervision
Execution Period
1984 – 1994
2004 – 2011


State of the Art in run-of-river power plants

The technology for run-of-river power
plants is now about 120 years old. Some
of the first schemes were built along the
river Rhine between 1895 and 1905.
During the last 120 years considerable
developments have taken place in
technical fields as well as in the
sustainability of such schemes.


State of the Art in Run-of-river power plants

• The reservoir level has to be kept
largely constant (head) and inflowing
water is constantly released either
through the turbines or the spillway
• The water is not stored (except
impounding) and therefore the mean
daily flow regime of the river is not
affected
• This is in contrast to high head storage
schemes where large volumes of water
are stored by means of high dams
– storing excess water during the high flow
season and releasing water during the low
flow season and
– accumulating the river flow sediments in the
reservoir



Today the following main principles are used in the design of the run-
of-river power plant:
– to built the weir and power structure as flexible as possible allowing the routing of
floods, sediments and nutrients directly through the system.
– to allow migration of fish and other aquatic animals through or around the dam
structure
– to have the best available equipment to avoid pollution, to allow downstream fish
migration and best use of the energy
– to allow for efficient navigation and to support recreation
– to satisfy the highest safety standards according national and international norms
– to support the general development of a region with the supply of safe, reliable
and clean energy



Various upstream and down stream fish migration systems e.g. fish
lock, fish ladder, natural by-pass channel, fish lift etc.
Protection of the area and ban of fishing and hunting in the vicinity of
all structures.


Fish Friendly Turbine


Fish Friendly Turbines:

Mortality of fish passing through turbines

Turbine Type Length of Fish
5-10 cm 30-50 cm
Francis >50% up to 100%
Kaplan 5-10% 15-30%
Fish-friendly turbines <5% 5-10%



Release of Sediments
– Most of the larger run-of-river schemes
with dams / weirs larger than about 20m
height are equipped with larger bottom
outlets for sediment release.
Examples:
– India, CWC request from public and
private developers the use of large
bottom outlets is required for the
continuous release of sediments during
the monsoon period.
– China, some large run-of-river dams
have sediment outlets e.g Three
Gorges
– Sudan, Merowe (Nile River), large
Sediment outlets were provided
– France, CNR will explain in their
presentation

MRC design guidelines

• The preliminary MRC design guidelines is one of the documents
developed for the implementation of the 1995 Mekong Agreement to
assure a sustainable development of the Mekong River Basin
• The guidelines deal with the following issues:
– Navigation lock system
– Fish passing facilities
– Sediments
– Water quality and aquatic ecology
– Safety of dams
• For downstream countries the issue of sediments and nutrient is of
particular interest for the long-term development of the lower Mekong
Regions


Xayaburi scheme and other hydro schemes in the Mekong
Upstream Hydropower developments:
1. Manwan HPP, 1550 MW, 132 m high dam with
seasonal storage
2. Jinghong HPP, 1750 MW, 108 m high dam
3. Nouzhadu HPP, 5850 MW, 261.5 m high dam, multi-
annual storage
4. Xiaowan HPP, 4200 MW, 294.5 m dam, multi-annual
storage
The schemes under development
(Xiaowan & Nouzhadu) are
storage schemes and will also trap
large amounts of sediments to secure
the operation of the d/s power plants.
Reference: Department of
Sedimentation, China Institute of
Water Resources Hydropower
Research

Downstream hydropower
Developments:
1. All d/s schemes are run-of-river
schemes.
2. None of this schemes have any pond
larger then a few hours of operation
3. Dam heights are below 30m


Xayaburi scheme, Overview


Xayaburi scheme, Main Features

Country: Lao PDR
Location: Xayaburi town, Approximate 80 km south of Luang Prabang
Commercial operation: October 2019 (expected)
Construction cost: $3.8 billion
Owner(s): Xayaburi Power Company Limited (XPCL)
Dam and Spillways
Height: 32.6 m
Length: 820 m
Type of spillway: 7 x radial gates, 4 low level outlets
Spillway capacity : 47’500 m3/s
Pond Capacity : 726 Mio m3, filling time with mean Mekong flow about 50 hours
Catchment area: 272,000 km2
Full supply level: 275 m a.s.l.
Power station
Hydraulic rated head: 18 m
Turbines: 7 x 175 MW Kaplan-type, 1 x 60 MW Kaplan-type
Maximum capacity: 1,285 MW
Energy Production: 7’405 GWh,
Export to Thailand 6’985 GWh supplies electricity for 3 Mio people or 750’000 families
For Lao PDR 420 GWh supplies electricity for 1 Mio people or 200’000 families


Xayaburi scheme, Construction Sequences
Cofferdam completion
schedule

May 2013

schedule

May 2013

Stage 1 Intermediate
DOWNSTREAM Block completion
schedule
Jun 2014

River diversion phase 1: construction cofferdams at the right side of the Intermediate block


Navigation Lock and
Spillway completion
schedule
Oct 2014

DOWNSTREAM

River diversion phase 1: construction Navigation log and spillway


Cofferdam removal
schedule

Oct 2014

Cofferdam removal
schedule

Oct 2014

Cofferdam completion schedule
schedule
Jun 2015
DOWNSTREAM
Jun 2015

River diversion phase 2: construction coffer dam at the left side of the Intermediate block



Main structure of
Powerhouse & Fish
ladder completion
DOWNSTREAM schedule
Mar 2018

River diversion phase 2: construction coffer dam at the left side of the Intermediate block



Cofferdam removal
schedule
Cofferdam removal
schedule Powerhouse Mar 2018
DOWNSTREAM
commissioning
Mar 2018 Sep 2019

River diversion phase 2: removal coffer dam at the left side of the Intermediate block


Role of Pöyry

• Contractual basis:
– Consulting Services Agreement for Compliance Review
– Between GOL and Pöyry Energy (5. May 2011)
• Scope of work: to report on whether
– Xayaburi Power Company (Owner) has complied with and satisfied the
Mekong River Commission (MRC) Design Guidelines
– GOL and the Owner have taken into consideration the comments
submitted by the MRC member countries during the Prior Consultation
Process
– GOL and Owner have complied with the terms of “Prior Consultation
Project Review Report on Xayaburi Project”, dated 24 March 2011
– Issues relating to development, construction and implementation of
Xayaburi and any discrepancies, conflicts and needs for changes in
connection with comments by the riparian countries


Role of Pöyry, Compliance Study
Pöyry has performed in 2011 a Compliance Study based on the previous
documentation on the following topics.
– Following the “Prior Consultation Process” according to the MRC guidelines, the
MRC stakeholder countries issued comments on Xayaburi project
– Critical comments were raised by Vietnam, Cambodia and Thailand
– Main items of concern and potential improvements are:
• Retention of sediment
• Migration of fish
– Pöyry carried out a Compliance Report with the objective to:
• Assess comments made by stakeholders and MRC on the current design
• Evaluate these comments against the MRC guidelines
• Identify points where the current design does not fully follow the MRC guidelines
• Propose measures to make the Xayaburi project fully compliant with the MRC guidelines
– The Compliance Report was issued to the Government of Lao in August 2011.
– Continuous assistance to the Government of Lao to address the technical queries
raised.


Main issues raised in the Prior Consultation Process

• The main concerns of the riparian countries are:
– Trans-boundary issues
– Certain impacts not addressed in as great detail as one would like
• Sediment trapping
• Nutrients
• Fishery
• Biodiversity
• Socio-economic aspects
• These concerns can be remedied during the construction stage by:
– Additional investigations recommended
– Implementation of certain design changes
• Providing of flushing gates to allow release of sediments
• Improvement of fish pass facilities



• Findings MRC Expert Group Safety of Dams
– Issues will be taken into account
• Findings MRC Expert Group Navigation Lock System
– Suggested changes will be introduced
• Findings MRC Fishery Expert Group (fish ecology and fishery)
– Gaps are identified and recommended actions will be implemented
• Findings MRC Fishery Expert Group (fish passage facilities)
– Recommendations are reasonable and applicable recommendations will
be checked and taken into account



• Findings MRC Fishery Expert Group (socio-economics and rural
livelihood aspects)
– Baseline investigation
– Monitoring
– Compensation measures
• Findings MRC Sediment Expert Group on sediments
– Sedimentation during construction
– Adaptive management of flushing devices
• Uncertainties considering available data
• Uncertainties considering future development
• Mitigation of sediment concentration peaks


Dam safety
• General design principles
– State of the art design principles and design methods are being used
and which are in line with the size and importance of the project
• Overall project safety concept
– The concept is being developed in which the different project parts (or
elements) will be design according to different criteria, depending on
their importance and damage potential. Applies to civil works and also
all equipment.
• Flood design
– Follows internationally accepted concepts
• Seismic design
– ICOLD guidelines will be followed where project parts will be designed
for OBE (operation basis earthquake, 145 yr), DBE (design basis
earthquake, 475 yr) and checked against the SEE (safety evaluation
earthquake, 10’000 yr), depending on their hazard potential
• Design complies with MRC design guidelines


Sediment measures proposed by Pöyry (1)

• Main concerns expressed
– Reduction of sediment content in Mekong River downstream of Xayaburi
– Can have detrimental effects up to Mekong delta in Vietnam
– Leading there to costal erosion and intrusion of sea water
– Reduction of nutrition content in Mekong River downstream of Xayaburi
– Having detrimental effect on fish population
– Leading to reduction of fishing yields in River downstream
– Negatively affecting downstream population
• Current sediment transport regime
– The main sediment transport in the river takes place during the high flow
season
– In the present state the yearly sediment flow in the river is in a stable
state, although influenced by the construction of dams in China (see
explanations of CNR)



• Basic requirement for sediment transport
– Xayaburi dam must be a transparent dam and mimic the natural
conditions (see MRC Guidelines)
– This means the dam must be capable not to retain and store the
sediments, but to release them towards downstream in natural way
• Introduction of low level outlets
– The original spillway outline design has been adapted by introducing 4
large capacity low level outlets equipped with radial gates
– Their dimensions are 12 m (width) and 16 m (height)
– Their sill level is 14 m lower than the spillway sill level
– The number of the original spillway openings has been reduced by 3
openings and the spillway sill level has been lowered by 2m
• Purpose of the low level outlets
– The low level outlets will allow, in combination with the spillway, to
• route sediment loaded flood flows through the available low level and spillway
openings and to
• draw down the reservoir and to flush the sediments towards downstream



• Cross section of low level outlet



• Cross section of spillway outlets


Sediments (5)

• Longitudinal section along spillway complex, showing both spillway
opening and low level openings

252

238
230



• Timing of sediment release
– Flood routing will be done during high river flows in the flood flow season
– Reservoir flushing will be done also during the flood season primarily
during the weekend
– The operations will be done in each year in order to mimic close natural
conditions
• Effect of these operations
– These repetitive operations will prevent the excessive accumulation of
sediments in the reservoir and which would be lacking in the downstream
• Control of sediment concentration
– Too high sediment concentrations in the water released through the low
level outlets would be detrimental to the river fauna
– The sediment concentration will be controlled by combined release
operations through the low level outlets (high concentration) and the
spillway openings (low concentration)



• Control of effect of these operations
– Potential sedimentation in the reservoir will need to be monitored by
repetitive bathymetric surveys
– Based on these results the flood routing and reservoir flushing operations
can be adapted to the current needs
– The installed release facilities offer full flexibility in this respect
– Monitoring of sediment concentration downstream during flushing
operation
• Coarse sediments
– Will need to be transported by mechanical means (see CNR note)
• Conclusion
– With the planned sediment release facilities and the intended operation
procedures it will be possible to achieve a project facility transparent to
sediments
– The sediments entering the reservoir will be transferred towards
downstream and potential negative effects of lack of sediment there can
be reduced to a minimum.

Flow Volume in Mekong River (1)

• Main concerns expressed
– The current flow volume of the Mekong River would be affected by
Xayaburi
– There would be less flow in the low flow season
– There could be higher flood flows
• Principle of run-of-river plant
– There will be no seasonal storage of water volumes
– The daily inflow into the reservoir corresponds to the daily outflow (see
also CNR)
• Effect of Xayaburi on downstream river flow conditions
– The current flow conditions in the river will therefore virtually not be
changed
– Minor changes are possible caused by daily variations in the power
production (causing reservoir fluctuations up to 30 cm)


Flow Volume in Mekong River (2)

– Equally minor changes are to be expected during the weekend, when
power production will be reduced
– The effect of such changes in the water flow, which can cause water level
variations limited to less than one meter, will reduce and finally equalize
along the river the further away downstream one gets from the dam
– The speed of the downstream water level variations can be controlled by
operational measures. There will thus be no sudden water level rises.
• Flushing operations
– Such operations can affect the downstream water flow for a longer river
stretch
– But flushing is only planned to be performed in the high flow season, when
changes in the river flow are less felt


Environmental and Social Impact Assessment (ESIA)
Carried out in 2007 - 2010
– The studies carried out be by the EIA Consultant cover all the aspects which need
to be covered for such a project and to comply with GoL requirements
– The local environmental law in Lao PDR follows Worldbank/IFC guidelines
– The total environmental cost are adequate even some of the total cost are
accounted under other topics, e.g. cost for fishpass
The environmental studies were approved by GoL on 13 September 2010
Main findings:
– Minor impact on local population, limited re-settlement required
– Minor impact on fish fauna, Environmental Impact Assessment (EIA) survey only
identified limited amount of fish species
Improvements recommended for the ESIA:
– Additional survey of actual physical conditions, especially on fish species
– Additional study on sedimentation


Technical Paper No. 8 by MRC
The MRC published the main results of the main fish
migration systems in the Lower Mekong Basin.
There are three different migration systems:
– The Lower Mekong Migration System (LMS)
This migration system covers the stretch from the Khone
Falls downstream to southern Cambodia, including the
Tonle Sap system, and the Mekong Delta in Vietnam.
– The Middle Mekong Migration System (MMS)
From just above the Khone Falls and upstream to the Loei
River, Thailand, the migration patterns are determined by
the presence of large tributaries connecting to the Mekong
mainstream.
– The Upper Mekong Migration System (UMS)
The third migration system occurs in the upper section of the
river, approximately from the mouth of the Loei River and
upstream towards the border between Lao PDR and China
(probably continuing into China).
Whereas the LMS and the MMS are inter-connected to a
large degree, the UMS appears to be relatively isolated,
with little “exchange” between the UMS and the other
migration systems. These populations should be regarded
as separate biological unit.


Technical Paper No. 8 by MRC
Main conclusions
1. The LMS and MMS migratory system are
playing a crucial role in the fisheries of the
Tonle Sap and Mekong delta.
2. The main spawning areas are in the LMS
and its tributaries.
3. The UMS is not (or very limited) connected
to the other migratory systems and has only
significance for the local fisheries in this
stretch of the river.
4. The highest biodiversity of the Mekong is in
the area downstream the Khone falls in
Cambodia.
5. The area between the mouth of the Loei
River and the Chinese Border: One of the
remarkable species in the UMS is the Giant
Mekong Catfish (Pangasianodon gigas). It
seems genetically to be a local subspecies
which might be separated from the
downstream population.


Fish Migrations

Mainly two types:
• anadromous: adults move upstream for reproduction, young move
downstream
• catadromous: adults move downstream (for reproduction in the sea),
young move upstream
Other migrations, over longer or shorter distances, not necessarily
related to reproduction.


General effects of HPPs

Main impacts of dams on fish migration:
• Dams interrupt upstream fish migration
• Downstream migrations go mainly through the turbines, with a high
risk of injury and mortality
• Fish that do not migrate for reproduction can be influenced by
fragmentation of the populations (no genetic exchange between
populations isolated by dams).


Main Measures Taken

Different measures have been developed for maintaining fish
populations and migrations, as:
• Fish ladders of different types
• Fish lifts
• Traps combined with transport
• Fish hatcheries and artificial restocking of rivers (in cases where
migrations could not be maintained and/or other conditions led or
contributed to the decrease in fish populations)
• Fish friendly turbines (turbines reducing risk of injuring or killing fish)


Fish Hatcheries

• Done in cases where barriers
(dams) are too high to be
passed with a fish ladder
• where other conditions (mainly
water quality) threaten fish
populations
• usually done only for
economically important species


Limitations

• Experience gained so far mainly in North American and European
rivers.
• Historic targets for measures were mostly Salmonids, i.e. fish which
can cope with fast currents and rather high steps.
• Recently, fish passes were implemented which are acceptable for a
wider range of fish species.
• Limited experience with fish passes in large tropical rivers but rapidly
growing with the experiences in other countries e.g. Brazil


Fish passing facilities (1)
• The present layout of the fish passing facilities comprises the
following main structures
– facility for upstream migration,
– fish passage recording system for upstream migration and
– facility for downstream migration
• The selected system is very
comprehensive and employs
a state-of-the-art technology
and covers all operational
conditions of the scheme
• However there are a few issues
which need improvement
to be in compliance with the
MRC design guidelines.


Main Problems Identified

• Potentially very high amount of biomass, i.e. a very large number of
migrating fish, during certain periods.
• High number of species with a very wide range of size.
• Therefore different migration requirements, especially concerning
manageable flow speed and height of steps.
• Limited knowledge of fish migrations (in terms of species, numbers
and seasonal distribution) at the project site.



The following investigations are recommended: Area influenced by Xayaburi dam

1. During the first stage of the construction: Area influenced by other dams

– develop additional baseline data on biology, ecology
and livelihood restoration
– improve the knowledge concerning the specific
requirements of the aquatic fauna on the fish passage
facilities
2. Investigations to be done independently from the
start of the construction when sufficient data are
available and under national or multinational
responsibility:
– additional investigations on trans-boundary issues on
hydrology and baseline investigations (fauna, flora,
habitat and socio-economy)
– A cumulative impact assessment of the mainstream
dams



The following design adaptations are
recommended:
• The fish passage facilities should be
amended as follows:
– The planned facility should be adapted as
follows:
• The downstream passage needs to be changed
at the inlet and outlet structures
• The velocity of the channels needs to be
adapted based on the proposed investigations
• The head difference between the pools needs
to be adapted (too high); this will lead to a
longer fish passing facility.
– There should be a system provided to allow
fish passage during construction
– Flexibility allowing later improvements if
required


– The MRC design guidelines require
several independent systems:
• The navigation lock should be adapted
to serve as a fish lock (also during
construction stage)
• Space for a fish lift should be prepared



Furthermore the following additional measures are recommended:
– Fish friendly turbines have been recommended in the feasibility study.
The degree of fish friendliness of the turbines should be verified with the
envisaged supplier of such turbines.
– It is recommended to set-up and operate a fish breeding station for the
augmentation of the existing fish
population and re-introduction of
locally endangered species for
release in a suitable river stretch.


Additional Recommendations

Given the lack in baseline information, the following is recommended:

• Aquatic baseline investigation concerning important habitats, spawning
areas, feeding areas, etc. within the future reservoir area.

• Fish survey: species inventory, migration patterns, abundance, total fish
biomass and larval drift.

• Identification of target species which represent whole groups (concerning
size and migration patterns, economic importance, etc.); swimming ability
and behavioural studies.


Fish Migration and Biomass Study

• A study has started which aims at providing additional information on
migrations and biomass.
• A suitable sampling site was chosen about 1 km d/s of the dam site.
• Main method applied is detecting migrating fish by means of hydro
sonar; four stations are being used (one fix on each river bank, two
mobile ones on boats).
• First field campaigns have been carried out end of March / April and
• First reports were submitted.


First Results

Size of fish migrating upstream (April 2012):

April 2012 (left) May 2012 (right)
• about 50% 0-20 cm • about 50% 0-20 cm
• about 5% > 1 m • about 10% > 1 m, up to 2.2m


First Results (2)


Follow-up

Ongoing activities:
• Follow-up on studies, monitoring results
• Initiation and supervision of implementation of environmental
measures on site
• Maintaining discussion and exchange of information with relevant
stakeholders
• Integration of new findings into design of fishway


Main project changes recommended and to be implemented

• The following changes will be implemented in the project
• A) Sediment transportation
– Provision of large capacity low level outlets
– Allows passage of the sediments towards downstream during high flow
season
– The aim is a transparent dam with respect to sediments
• B) Fish passage
– Fish passing facility in navigation lock
• Allows fish passage also during construction period
– Adaptation of fish ladder system (step height) depending on findings of
baseline studies
– Provision of a fish lift (additional) if baseline studies indicate the need for it
• C) Navigation locks
– Improvements in upstream lock approach area (avoidance of bends)
– Changes in lock feeding system (making operation more smooth)


Recommended investigations
Investigations to be carried out specifically
for Xayaburi (i.e. by the developer) during
the construction stage:
• Fish survey and related studies for optimising
fish pass facility
• Additional socio-economic studies on the
effects of Xayaburi in the reservoir area and in
the downstream proximity
• Continuous measurements of flow, water
quality and other parameters
• Baseline study for sediment content and
sediment composition of Mekong river in
project area
Framework studies to be carried under national or multinational
responsibility, independent from the start of the construction:
• CIA and trans-boundary assessment of effects of all HPP developments in the
Mekong basin (also taking into account effects of planned and operating dams in
China).


Ongoing investigation works for the detailed design

The following main topics of investigations are on-going or have
already been completed:

2010 2011 2012
S/N Investigation Topics
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
1 Seismic investigation
1.1 Geological investigations
2 River quality measurements
3 Hydrological measurements
3.1 River Sedimentation sampling
4 Meteorology measurements
5 Additional ecological studies
5.1 Fish survey
6 Additional social studies


Conclusions by Pöyry
• The Compliance Study performed by Pöyry has established those
areas where the project was not yet fully in compliance with the MRC
preliminary design guidelines
• Proposals on actions to be taken to bring the project into full
compliance were made
• The necessary actions have all been initiated by now and which
consist of
– Actual changes to the project and its future operation
– Additional studies and investigations in areas where knowledge deficits
were identified
• With these actions taken it can be considered that the project will not
have unacceptable negative effects and restrictions on the population
living downstream of the project, and therefore also not in the
neighboring countries further south
• Following this carefully balanced approach the project fulfills the
highest standards in accordance with the current State-of-the-Art


THANK YOU!


Xiyaburi dam project poyry july_2012_v_03

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