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August 2015
PakBeng Hydropower Project Updated FS Report
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Pak Beng HPP
Table of Content • Summary • Design standards • Updated FS Report based on CNR review • Discussion of critical issues
In Mar, 2013 Technical Report (FSL 340m, installed capacity 912MW)
In January 2010
Technical Report (FSL 340m, installed capacity 855MW)
In December 2008
FS Report (FSL 345m, installed capacity 1230MW)
In December, 2007
KHIDI Contract.
In August, 2007
MOU
3
Design and investigation process
In AUG, 2015
Updated FS.
In JUNE, 2014
FS for Independent Review
4
Design and investigation process
Project Layout
5
lock
sand sluice
discharge sluice
sand barrier
Bottom outlet
powerhouse
Fish way
Project Layout
6
lock
sand sluice
discharge sluice
Bottom outlet
intake
Fish way
Design Standards
Updated FS Report is in compliance with following standards:
Lao Electric Power Technical Standards;
Preliminary Design Guidance for Proposed Mainstream Dams in the Lower
Mekong Basin, and related MRC regulations;
Periodic Technical Bulletins on the Safety of Dams issued by the International
Commission on Large Dams (ICOLD) ;
World Bank, Operational Policy 4.37;
China Power Industry Standard;
7
Updated of FS Report based on CNR review
Hydrology
1.Hydrological data
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Previous FS Report Updated FS Report Run off data 1960~2004 1960~2014 Flood data 1960~2004 1960~2008
Updated of FS Report based on CNR review
Hydrology
2. Rating curve at the dam site KHIDI established 4 groups of stage gauges near Pak Beng Dam Site, the measured series from
2008 ~2014.
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295
300
305
310
315
320
325
330
335
0 2000 4000 6000 8000 10000 12000 14000 16000
H(m)
Q(m3/s)
Calculated by Interzone Method
Rating Curve Adopted
Measured Discharge
Updated of FS Report based on CNR review
10
Hydrology 3. Impact of HPP located upstream Pak Beng project In this stage, discharge at Pak Beng dam site is extended to Jun 1960-May 2014. During
the design we have consider the influence of upstream Cascade.
Updated of FS Report based on CNR review
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Hydrology
4. Planned operation pattern
Updated of FS Report based on CNR review
Hydrology
5.Automatic system of hydrological data
collection and transmission
The new version of Automatic system of
hydrological data collection and transmission has
been compiled, and submitted as Appendix 4A.
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Updated of FS Report based on CNR review
Sediment
1.Sediment Sampling After Independent review by CNR, according
to the Expert opinion, Suspended load sampling
was carried out at Pak Beng hydrologic station
during 25 June.
13
Updated of FS Report based on CNR review
Sediment
1.Sediment Sampling According to the expert's opinion, CNR sampling result is adopted during the design.
KHIDI will carry out the daily sediment tests, Monitor sediment concentration at Pak
Beng station immediately, and make another Suspended load sampling when the
discharge is big and sediment concentration is high, and adjust our result.
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Updated of FS Report based on CNR review Sediment 2. Reservoir sedimentation
According to the sediment grading result, one-dimensional model has been corrected, and the parameter sensitivity analysis is added. Two-dimensional sediment mathematical model of the project area and three-dimensional sediment mathematic model are carrying out and will provide the latest research results and subjective report after it complete.
Physical model test have been commissioned to Sichuan university, after the completion of the work will provide a research report.
Sediment tour gauging are carrying out in Pak Beng station, Test item includes sediment concentration and grading.
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Updated of FS Report based on CNR review
Sediment
3. The design of the spillways CNR Comments “The design of the spillways as well as the outlet works has to be
improved according to the recommendations suggested by CNR. Physical modeling of the
dam area is required in particular to refine the positioning and the sizing of the dam gates
(i.e. surface spillway, low-level outlets and bottom outlets for sand flushing).”
Two low level sand sluice gates are added on the project layout(show in project layout),
bottom elevation is 302m.
Detailed instructions about this problem refer to Discussion of critical issues.
16
Updated of FS Report based on CNR review
Sediment 4. Sediment management
Sediment management report have been compiled, Detail design of sediment
management strategies are shown in Appendix4C-SEDIMENT MANAGEMENT.
Sediment management strategies include: Dam operation for sediment discharging,
sediment flushing measures, time selection of sediment flushing and Eco-friendly flushing
for sediment, etc.
Through the above measures can reduce or avoid the impact on the river due to the
construction and operation of power station .
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Updated of FS Report based on CNR review
Sediment
5. Sediment monitoring Overall design report of sediment monitoring system have been compiled, show in
Appendix 4B. Additional details regarding techniques, devices and survey frequency are
include in the report.
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Updated of FS Report based on CNR review
Sediment
5. Sediment monitoring Main items of the sediment observation include:
• (1)Monitoring water and sediment in/out the reservoir;
• (2)Monitoring of water surface line in front of the dam and at the tail section of the
reservoir;
• (3)Monitoring of sediment deposition in the reservoir area;
• (4)Monitoring of sediment deposition in the project area;
• (5)Monitoring of downstream river course;
• (6)Monitoring of bank deformation in the reservoir area. 19
Updated of FS Report based on CNR review
Dam safety For dam safety, the best International practice is adopted. Our design, engineering, construction and operation of the plant are in accordance with the following standards : Lao Electric Power Technical Standards; The World Bank Operational Policy 4.37 on the Safety of Dams; Periodic Technical Bulletins on the Safety of Dams issued by the International
Commission on Large Dams (ICOLD) Preliminary Design Guidance for Proposed Mainstream Dams in the Lower Mekong
Basin, and related MRC regulations;
China Power Industry Standard;
20
Updated of FS Report based on CNR review
Dam safety The following management document will be finished and updated as work going on: (i) a construction supervision plan (ii) a quality assurance plan (iii) an instrument plan (iv) an operation and maintenance (O&M) plan, and (v) an emergency preparedness plan (EPP). All of these will be the guide line for our actual work to ensure dam safety.
21
Updated of FS Report based on CNR review
Navigation After the final review of CNR the final design of navigation lock is shown below.
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Fish way With reference to the latest investigation on fish and historical data, we studied the
kinds, quantity of fish resource, and living habit. And referring to the experience on the
world, by pass channel of fish passage is selected.
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Updated of FS Report based on CNR review
Updated of FS Report based on CNR review Fish passage
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Updated of FS Report based on CNR review
Water quality Based on the study and research on the velocity, depth, flow, and other hydrological data, together with
the pollution source and present water quality, we predict the changing trends of water quality during the operation period. In order to ensure water quality safety, we propose the following environment protection measure, and monitoring plan:
1、The tributaries protection both upstream and downstream the dam including the Nam Tha , Nam Ngao, Nam Ing and Nam Beng River.
2、Cleaning of reservoir zone before impoundment. 3、Water treatment of sewage. 4、 According to the MRC and EMMP, environmental management and monitor plan is presented .
The parameter include: Temperature, pH, Dissolved oxygen, Biochemical oxygen demand, Total nitrogen, Total phosphorus, Total solids, Transparency, Chlorophyll-a, Coliforms, Harmful substances, and so on.
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Discussion of critical issues
Sand sluice The CNR experts suggested some comparatively large bottom outlets for discharging coarse sediment. But we suggest design with two bottom outlets of present size, not larger outlets, based on the following consideration: -- Comparatively large bottom outlets will be operating comparatively unsteady under water; --- Comparatively large bottom outlets will cause the downstream water level changing dramatically, this is a thread to downstream navigation. -- The lower outlets operate, the more problems would occur, such as blockness and abrasion .
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Discussion of critical issues
Sand sluice Sediment deposition in the reservoir area is controlled by the operating water level of the power station, to add low level outlets or to reduce the elevation of spillway will only improve the situation of sediment at the dam base partially, and will not solve the problem of Sediment deposition in the reservoir completely. Compared the design with the added now two bottom outlets with previous design without bottom outlets at this position, we did two-dimensional sediment mathematical model of the project area, the result shows that:
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Discussion of critical issues
Sediment flushing effect without the sand sluice gates
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Discussion of critical issues
Sediment flushing effect with the sand sluice gates
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Discussion of critical issues
Sand sluice • We think it is not so effective, in terms of flushing, to add the two low level sand sluice
gates, secondly investment increase a lot, thirdly the two low level sand sluice would operate with potential risk.
• So we suggest that we do not add the two low level sand sluice gates, and the previous design will be adopted.
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Discussion of critical issues
Navigation According to MRC guidelines and the review comments of CNR, the design reference of codes and norms are as following: According to China’s “Overall design specification of navigation lock”, the occurrence probability of maximum water head of navigation lock is only 5%, so it won’t last long. And after the next cascade dam is built the downstream water level will be EL.310m, so the navigation lock water head is under 30m at most time.
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Discussion of critical issues Navigation
During the design process of navigation lock the following tests have been done;
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Discussion of critical issues
Navigation Data collection equipment
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Discussion of critical issues
Navigation Valve test video
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Discussion of critical issues Navigation
Conclusion: Based on the physical model results of navigation lock, the operation conditions under different conditions are reasonable, so when the maximum water head occurs the one step navigation lock can operate safely. And in China and world many navigation locks of water head exceeding 30m have been built and comes into service, so the design of ship lock (water head exceeding 30m) can also operate well, the examples are as follows:
35
Discussion of critical issues
Navigation Five-step ship lock of Three Gorges on Yangtze River
The maximum water head of the middle step is 45.2m
36
Discussion of critical issues
Navigation Ship lock of Wan An HPP on Ganjiang River (in Jiangxi Province)
The maximum water head of lock is 32.4m 37
Discussion of critical issues
Navigation Ship lock of Yin Pan HPP on Wujiang River (in Chongqing Municipality)
The water head of lock is 36.46m.
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Discussion of critical issues
Navigation water head over 30m on the world
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No. HPP Name Country Type Max. Head (m) 1 Uuski-Camino Alsky HPP Soviet Union One-Step Lock 42.0
2 Walter Pudding HPP U.S.A One-Step Lock 39.6
3 Dnieper HPP Soviet Union One-Step Lock 38.7
4 Calem Batllo HPP Portugal One-Step Lock 34.5
5 John Day HPP U.S.A One-Step Lock 34.5
6 Vale Ira HPP Portugal One-Step Lock 33.0
7 Sobral Reading HPP Brazil One-Step Lock 33.0
8 Pavlov HPP Soviet Union One-Step Lock 32.0
9 Lower Granite HPP U.S.A One-Step Lock 32.0
10 Ice Harbor HPP U.S.A One-Step Lock 31.4
11 Lower Monumental HPP U.S.A One-Step Lock 31.4
12 Little Goose HPP U.S.A One-Step Lock 30.8
13 New Wilson HPP U.S.A One-Step Lock 30.5
14 Perumishin HPP Brazil One-Step Lock 30.3
Discussion of critical issues
Navigation Maximum longitudinal forces are designed according to China’s “Ship lock water
conveyance system design specification”(JTJ306-2001) standard, and on this bases we compare the design between china standard and the USA standard, it is show in the table below:
Comparison between hawser force design And also the hawser force of 500t vessel is obtained from physical test, the maximum hawser force is 16.5KN, it is less than the allowable force(25KN), so the design is safe.
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Thank you
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