Water Power and Dam Construction - Issue March 2009
Подождите немного. Документ загружается.
w w w . r iz z o a s s o c . c o m
'(6,*1 $1$/<6,6 ,163(&7,216 &216758&7,21 0$1$*(0(17
&25325$7( +($'48$57(56 3,776%85*+ 3(116</9$1,$ 86
3+21( )$;
PROUDLY
BUILDING ON
YEARS
OF RCC & DAM
CONSTRUCTION
EXPERIENCE.
2
5
ON
DAM
CTION
$*(0(17
E.
12 MARCH 2009 INTERNATIONAL WATER POWER & DAM CONSTRUCTION
DIARY
Let IWP&DC’s readers know about your forthcoming conferences and events.
For publication in a future issue, send your diary dates to: Carrieann Stocks, IWP&DC, Progressive Media Markets Ltd, Progressive House,
2 Maidstone Road, Foots Cray, Sidcup, Kent, DA14 5HZ, UK. Alternatively, email: cstocks@progressivemediagroup.com.
DIARY OF EVENTS
May
11-13 May
National Hydropower Association
A
nnual Conference 2009
Washington, DC, US
CONTACT: Nation al
Hydrop ower Association, 1
Massachusetts Avenue, NW, Suite
850, Washington DC 20001, US.
Tel: +1 202 682 1700.
Fax: +1 202 682 9478.
Email: help@hydro.org.
http://www.hydro.org.
13-15 May
Second National Symposium on
Dam Safety
Eskisehir, Turkey
CONTACT: Eskisehir Osmangazi
University, Earthquake Research
Center, 26480 Bah Meselik,
April
20-22 April
2nd Int . Conference on Hydro
-
power Technology & Equipment
Beijing, China
CONTACT: Wang Yu, Lei Dingyan,
Sun Zhuo, Rm. 431, Main Building,
No.1 Lane 2 Baiguang Rd. Xuanwu
Dist, Bejing 100761, China.
Tel: 86 10 63414390; 63414391;
63414394.
Fax: 86 10 63547632.
E-mail:
cshe@checc.cn.
www.hydropower.org.cn/ichte/en/in
dex.jsp.
20-24 April
United States Society on Dams
Annual Conference – Managing
Our Water Retention Systems
Tennessee, US
CONTACT:
United States Society on Dams
(USSD), 1616 Seventeenth Street,
Suite 483, Denver CO 80202, US.
Tel: +1 303 628 5430.
F
ax: +1 303 628 5431.
Email: stephens@ussdams.org.
http://www.ussdams.org.
28-29 April
Small Hydro 2009
Vancouver, Canada
CONTACT: Carrie ann Stocks,
Editor, International Water Power
& Dam Construction, 2 Maidstone
Road, Foots Cray, Sidcup, Kent
DA14 5HZ, UK.
Tel: +44 (0) 208 269 7777.
Fax: +44 208 269 7804.
Email:
cstocks@progressivemediagroup.com
Web:
www.wat erpowermagazine.com/
smallhydro2009.
Eskishehir, Turkey.
Email: info @bara jguve nligi.org;
ogudam@ogu.edu.tr.
17-21 May
W
orld Envi ronmental & Water
Resources Congress
Kansas City, Missouri, US
CONTACT: Adele C. Dicken,
CMP, Conference Manager, ASCE
World Headquarters, 1801
Alexan der Bell Drive, Reston,
Virginia 20191-4400, US.
Email: adicken@asce.org.
20-21 May
All Energy 09. Scotland, UK
CONTACT: Media Generation
Events Ltd, 34 El lerker Gardens,
Richmo nd, Surrey, TW10 6AA,
UK.
Tel: +44 20 8241 1912.
Fax: +44 20 8940 6211.
WWW.WATERPOWERMAGAZINE.COM MARCH 2009 13
DIARY
Let IWP&DC’s readers know about your forthcoming conferences and events.
For publication in a future issue, send your diary dates to: Carrieann Davies, IWP&DC, Progressive Media Markets Ltd, Progressive House,
2 Maidstone Road, Foots Cray, Sidcup, Kent, DA14 5HZ, UK. Alternatively, email: cdavies@wilmington.co.uk, or fax:+44 208 269 7804
DIARY OF EVENTS
June
14-16 June
24-29 May
23rd ICOLD Congress, Brasilia
CONTACT: Brazilian Committee
on Dams, Rua Real Grandeza 219,
Bloco C S/1007 Botafo go, Rio de
Janiero, Brazil.
Tel: (055 21) 25285320.
Fax: (055 21) 25285959.
www.cbdb.org.br.
1st Internatio nal Conference on
Civil Engineerin g – Towards a
Better Future. Coimbra, Portugal
CONTACT: Conference
Secretariat, CI-Premier Pte Ltd, 150
Orchard Road, #07-14, Orchard
Plaza, Singapore 238841.
Tel: +65 6733 2922.
Fax: +65 6235 3530.
Email: cipremie@singnet.com.sg.
http://www.cipremier.com.
17-19 June
4th International Conference on The
Concrete Future. Coimbra, Portugal
CONTACT: Conference Secretariat
CI-Premier Pte Ltd (address details
as above).
Email: cipremie@singnet.com.sg.
24-26 June
IHA Congress 2009
Reykjavik, Iceland
CONTACT: Intern ational
Hydrop ower Association , Fifth
Floor West, Nine Sutton Court
Road, Sutton, Surrey. Uni ted
Kingdom, SM1 4SZ.
Tel: +44 20 8652 5290.
Fax: +44 20 8770 1744.
Email: iha@hydropower.org.
www.hydropower.org.
July
27-30 July
Waterpower XVI
Spokane,
Washington, US
CONTACT: HCI Publ ications,
410 Archib ald Street, Kansas City,
MO 64111, US .
Tel: +1 816 931 1311.
Email: info@hcipub.com.
October
27 September – 1 October
Dam Safety 2009
Florida, US
CONTACT: Association of State
Dam Safety Officials (ASDSO),
450 Old Vine Street, Lexington
KY 40507, US.
Tel: +1 859 257 5140.
Fax: +1 859 323 1958.
Email: info@damsafety.org.
http://www.damsafety.org.
26-28 October
Hydro 2009
Lyon, France
CONTACT: Hydropower &
Dams Editor ial Office,
Aqua~M edia Inte rnational Ltd,
123 Westmead Road, Sutton,
Surrey SM1 4JH, UK.
Tel: +44 20 8643 5133.
Fax: +44 20 8773 7255.
edit@hydropower-dams.com.
www.hydropower-dams.com.
14 MARCH 2009 INTERNATIONAL WATER POWER & DAM CONSTRUCTION
INSIGHT
C
ENTRAL Asia [1] is an arid region.
Its fertile plains are former deserts
made arable by vast irrigation sys-
tems. Most of the water comes
from the high mountain ranges of Kyrgyz
Republic and Tajikistan (and to a lesser
extent from Afghanistan) channelled down-
stream to Kazakhstan, Turkmenistan and
Uzbekistan by the Amu Darya and Syr Darya
rivers. Over the last century Soviet engineers
harnessed these water resources with an
extensive system of dams, reservoirs and irri-
gation canals to support the rapidly growing
populations of the downstream countries and
their agricultural production that in turn sup-
ported the Soviet Union. The reservoirs also
produce electricity, but local peak demand for
electricity is in the cold winter months, when
water needs to be stored for summer irriga-
tion release. During Soviet days, downstream
countries provided the upstream countries
with gas and coal in the winter to allow them
to generate heat and power without releas-
ing water needed for the summer.
With the breakup of the Soviet Union the
elaborate water and energy sharing agree-
ments among the Soviet Republics of Central
Asia broke down, and the previously inte-
grated regional water and electricity infra-
structure became fragmented and suffered
from lack of maintenance. With overuse and
poor water management agricultural yields
fell, and the water levels of the Aral Sea
dropped precipitously, leaving behind a mere
remnant of what was previously one of the
largest inland seas in the world.
As a result, the provinces around the Aral
Sea suffered great hardships and increases
in poverty. While the Central Asian
republics of the Former Soviet Union have
avoided military conflict over scarce water
resources, their relations have at times been
strained, especially between Tajikistan and
Kyrgyz Republic on the one side and
Uzbekistan on the other.
Over the last two years two interrelated
developments have aggravated this difficult
situation: First, the two poor upstream
countries, Kyrgyz Republic and Tajikistan,
have started to develop their hydro
resources for export. Downstream c oun-
tries, and especially Uzbekistan, consider
this a challenge to their water security.
Secondly, changes in precipitation and tem-
peratures threaten the supply of water and
energy in the region. This has created –
together with rising food insecurity and the
impact of the global economic crisi s – the
potential for a ‘compound crisis’ in the
region in 2009 that combines humanitarian,
economic and environmental threats espe-
cially for Kyrgyz Republic and Tajikistan.
Let us look in turn at these two issues: the
long-term opportunities and challenges of
unlocking the hydro resources of Central
Asia, and the short term threats of a com-
pound crisis.
L
ONG TERM HYDRO
DEVELOPMENT OPPORTUNITIES
The Soviets planned and built hundreds
of dams to regulate the water flow i n the
Aral Se a river basin for irrigation use
and for generating electricity. Among
them was Ro gun dam in Tajikistan,
pla nned for a height of 335m and started
in 1976, but never finished, since the break-
up of the Soviet Union and Tajikistan’s sub-
sequent civil war brought construction to a
halt in 1991 [See Figure 2].
In May 2008 the co untry’s Pre sident,
Emomali Rakhmon, announced tha t con-
struction had re sumed [2]. While initially
drawing on the country’s limited budgetary
resources, the Tajik government hopes to
attract foreign financing for this project.
When completed, the dam will generate
3600MW of power. This is enough to
supply much of Tajikistan’s electricity needs
and to allow exports to Tajikistan’s neigh-
bours, i ncluding to Afghanistan and
Pakistan through a 1000MW transmission
line, which has yet to be constructed.
While a preliminary dam built in Soviet
days was washed away by floods in 1993,
there remains a network of huge tunnels and
caverns carved inside the mountains on both
sides of the river. These will house the eight
turbines that will eventually generate the
power. While the completion of the dam is
still expensive at a planned cost of US$2.2B,
the fact that a significant part of the work
has already been carried out strengthens the
economic justification for pushing forward
with the project.
The plan is to complete the dam in stages
over the coming 8-10 years, while filling the
reservoir could take up to 18 years, although
power generation would start earlier. The dam
is to be built of rock and earth, which will
allow it to absorb potential seismic shocks
better than a concrete structure, an important
consideration in this earthquake-prone region.
While eager to involve others in the financing,
the government intends to retain control over
the dam and its energy output, a fact that may
deter others from participating.
Another potential obstacle is that some
downstream countries object. U zbekistan
has been especially concerned that the large
storage requirements of the new dam will
endanger the essential supply of water to the
millions of Uzbeks dependent on the river’s
uninterrupte d flow during the summer
months when irrigation needs are highest.
Rogun is the largest of the dams current-
ly on the drawing board in Central Asia.
Others are under consideration, among
them the Kambarata 1 and 2 dams in neigh-
bouring Kyrgyzstan with a joint capacity of
2260MW and an estimated cost of US$2B.
The total capacity of currently planned
hydro investmen ts in Kyrgyzstan and
Tajikistan is 11,360MW at a total estimat-
ed cost of US$10.2B [3].
These pro ject s share similar characteris-
tics. First, beca use of their high costs they
cannot be funded b y national resources
alone – Rogun’s cost is about 85% of
Tajikistan’s gross na tional inc ome (GNI),
Kambarata’s cost is 7 7% of Kyrgyzstan’s
GNI. The two countries will have to attract
public or private investors from abro ad if
they are to proceed.
Second, the hydro dams will generate
large quantities of electricity that can meet
the rising national energy needs of the coun-
tries at costs much lo wer than imported
energy and will help avert the energy short-
ages currently prevailing during the winter
months in Kyrgyz Republic and Tajikistan.
Surplus power can be expo rted to neigh -
bouring countries, where electricity is also in
short supply and generation costs are at least
three to ten times higher.
Moreover, peak demand for electricity in
South Asia falls in the summer, which is also
the time of greatest water release for down-
Central Asia: long-term challenges
and short-term crises
Despite the pressing challenges elsewhere in the world, the international community must
pay close attention to water and energy developments in Central Asia, warns Johannes F
Linn. Long term development opportunities and short term threats need to be addressed
in order to avoid a compound crisis in which water and energy scarcity play a huge role
• a) D ownstream countries could pay
upstre am countries for the summer
release of water stored in the winter. This
in effect was the practice during Soviet
days, when downstream republics pro-
vided upstream republics with free gas
and coal to generate electricity and hea t
during the winter months. After the dis-
solution of the Sovie t Union, upstream
countr ies argued that water sho uld be
treated as a co mmodity and paid f or by
downstream count ries (at least i n terms
of the cost of maintaining and runn ing
the dams and turbines), while down-
stream countries rejected this notion on
the grounds that wa ter in transnational
rivers is a common goo d sha red equally
by all riparians.
• b) Downstream countries co uld build
dams and reservoirs on their territories to
catch the waters released by the upstream
countries during the winters for summer
use. Such reservoirs h ave already been
constructed (in Uzbekistan) and more are
curren tly under construction (the huge
Golden Centur y Lake in Turkmeni stan)
or planned (Kokserai reservoir in
Kazakhstan) [7]. The problem with these
downstream reservoirs is that they are an
inefficient and partial response. Since they
are located in flat land rather than deep
mountain valleys they are more expen-
sive, provide little or no hydroelectric
capacity, and lose lots of water to evapo-
ration and seepage.
• c) A third option is to build dams and
reservoirs upstream along the same river
or river system in sequence. This allows the
release of water from the higher reservoir
for electricity generation in winter, while
catching and storing the water in the sub-
sequent reservoir for summer release. In
INSIGHT
WWW.WATERPOWERMAGAZINE.COM MARCH 2009 15
stream irrigation needs. This makes power
exports from Central Asia to Pakistan and
eventually to India particularly attractive.
Major regional transmission lines are under
construction or being planned to allow power
exports from Kyrgyzstan and Tajikistan.
Third, global climate change is threaten-
ing Central Asia’s long term economic and
ecological stability as global warming is
melting glaciers in the region at an alarming
rate. In the last 50 years the waters stored in
the glaciers of Central Asia are estimated to
have shrunk by 25% and they are projected
to shrink by another 25% over the next 20
years [4]. These numbers are at best guess-
work for now, but they do reflect the broad
trends that will likely see major changes in
water flows of the principal rivers in the
region. Greater water shortages in the long
term wil l force Cen tral Asian countries to
use t heir available wa ter much mo re effi-
ciently than has been the case so far, espe-
cially in irrigation [5]. But they will also
make cooperative approaches to rational
storage and allocation of scarce wa ter
resources across the region much more
important if peace and prosperity in the
region are to be preserved.
If foreign financing is to be attracted,
detailed feasibility and environmental
impact studies still need to be conducted for
the new dams to assure that benefits out-
weigh costs, and that potential negative envi-
ronmental and social impacts can be
adequately mitigated. In the case of Rogun,
the World Bank has initiated such assess -
ments in pre paration for possible funding
[6]. In view of the con cerns o f the down-
stream countries, the rules of international
water co nventions need to be r espected.
There are various ways of dealing with the
allocation of transnational water resources:
the case of Ro gun dam the downstream
Nurek reservoir could serve this purpose; for
Kambarata dam the downstream Toktogul
reservoir is available.
Among these options, the last one may well
be the most feasible for the Central Asian
region, but it requires a level o f trust
among countries that is currently not uni-
versal ly present. The practical question
then is whether a mec hanism can be found
to provide appropriate guarantees for th e
downstream count ries that create the min-
i
mum of trust to permit cooperation in this
critical area.
Currently various efforts are underway to
try and find such a mechanism. This includes
a High-Level Group set up in 2006 by the
Eurasian Economic Community (EurasEC –
with Belarus, Ka zakhstan, Kyrgyzs tan,
Russia, Tajikistan and Uzbekistan as mem-
bers) to develop a strategy for the efficient
utilisation of water and energy resources in
Central Asia. It has been working on a strat-
egy document but apparently has not yet
reached agreement [8].
The Central Asia Regional Economic
Cooperation Forum (CAREC – whose par-
ticipants are Afghanistan, Az erbaijan,
China, Kazakhstan, Kyrgyzstan, Mongolia,
Tajikistan and Uzbekistan, as well as six
multinationa l institutions, inclu ding the
Asian Development Bank and the World
Bank) has also prepared an energy sector
strategy under which member countries
agreed on the broad principles for the devel-
opment of the region ’s hydroel ectricity
resources. The Shanghai Cooperation
Organisation (SCO – with China,
Kazakhstan, Kyrgyzstan, Russia, Tajikistan
and Uzbekistan as me mbers) in it s 2 007
summit agreed to develop an ‘energy club’,
but so far little is known about its practical
implementation and how it would address
the hydro power issues of Central Asia.
While the preparation of regional strate-
gies and broad understandings are helpful
for creat ing a platform for dialogue and
improved mutual understanding, the key
will be the pragmatic impl ementation of
major specific river basin projects, such as
Rogun for the Amu Darya and Kambarata
for the Syr Darya. A practical way to achieve
this would be the creation of a consortium
of partners, including all directly affected
countries, as well as possibly one or more of
the big neighbours (such as China or
Russia), the international financial organi-
sations and private financiers. The
Government of Tajikistan has in fact invited
Afghanistan, Kazakhstan, Kyrgyzstan,
Turkmenistan and Uzbekistan to join such a
consortium. Kazakhstan has responded pos-
itively to this invitation [9].
Such consortiums would operate under a
carefully crafted agreement that lays out the
key water and energy sharing arrangements,
the financing and management responsibil-
ities, and the arbitration mechanism in case
of unresolved disagreements. International
Figure 1: The central Asia region. Source: United Nations
16 MARCH 2009 INTERNATIONAL WATER POWER & DAM CONSTRUCTION
INSIGHT
financial institutions could be asked to pro-
vide gu arantees, which in turn would be
counter-guaranteed by the regional member
governments. Perhaps the best example of a
successful internationally backed river basin
agreement with lasting success is the Indus
Water Treaty which was signed in 1960
between India a nd Pakistan after years o f
arduous negotiations with the support of the
World Bank [10].
In sum, there are great potential benefits
to Central Asia and its neighbours that argue
for the swift implementation of cooperative
solutions for the development of Central
Asia’s ‘blue gold’. The principal responsibil-
ity for thi s rests with the co untries of the
region, but the big neighbours and the inter-
national communi ty can do much to help
create a supportive environment:
• Offering financial su pport for appropr i-
ately structured regional consortiums.
• Fund ing neutral third-party anal yses of
costs and benefits and of their distribution
across countries.
• Crea ting opportunities for constructive
dialogue and trust b uilding among th e
regional players.
• Stressing the shared long-term interests of
all concerned.
Of course, even under the best of circum-
stances, the construction of new hydro capac-
ity is a long-term proposition. Measures to
encourage more efficient utilisation of avail-
able water resources and emergency steps to
prepare for water and energy crises when they
threaten, as is the case right now, also need to
be promoted as a matter of high urgency.
A COMPOUND
WATER
-
ENERGY
-
FOOD CRISIS
Against the backdrop of the opportunities
and challenges of long term hydro energy
development in Central Asia, a water and
energy situation that is already difficult and
tense at best during years of normal weath-
er can quickly deteriorate into a major
humanitarian, economic and political crisis
for the region when climatic conditions are
adverse.
The years 2007-9 have been particularly
problem atic, since normal climatic cycles
(probabl y linked to the El Nino-La Nina
phenomenon) appear to be intensifying and
are overlaid on the long te rm effects of
global warming. The last major drought in
the region occurred in 2000-01. In 2007, a
new drought period began with an unusu-
ally hot and dry summer in much of
Central Asia, followed by an exceptionally
cold and dry winter.
The winter of 2007/8 had its most severe
impact in Tajikistan, where parts of the
country had to do without electricity for
weeks at a time, shutting down businesses
and schools, limiting hosp ital operations,
and forcing families to live without heat or
light during the winter months when tem-
peratures as low as -30˚C were not uncom-
mon. Even the capital, Dushanbe, was
severely affected by power cuts.
Tajikistan’s situation was aggravated by
the fact that Uzbekistan, plagued by its own
winter energy shortages, suspended gas
exports and limited transfer of electricity
through its territory. At the same time, the
food situation in the country deteriorated, as
farmers had to eat or sell their seed stock,
cattle ran short of feed, aquaculture suffered
from frozen ponds and streams, and food
supplies from neighbouring countries dwin-
dled along with rising prices [11].
Kazakhstan, the main grain exporter in the
region, temporarily banned exports, includ-
ing to some of its neighbours, reinforcing the
damage done by the world food crisis
beyond its borders.
The summer of 2008 was once again
unusually dry in large parts of Kyrgyz
Republic and Tajikistan, with the result that
the major reservoirs of these two countries,
Toktogul and Nurek, experienced sustained
levels much below normal. Like Tajikistan,
Kyrgyzstan depends on electricity for the
winter months. Going in to the winter
2008/9, both countries had to ration elec-
tricity in large parts of each country for
months on en d. Fortunately, so far this
winter has been relativel y mild, so the
humanitarian impact has been less severe,
even though the economic and social costs
of the disruptions of power supply are once
again significant.
The international reaction to the unfold-
ing water and related energy crisis in Central
Asia involved emergenc y ass istance for
Tajikistan in 2008. Among others, the US
provided nearly US$2.5M in emergency
relief to Tajikistan in 2008 [12]. The World
Bank provided a US$6.5M emergency grant
for rehabilitation of key energy facilities and
to assist with the development and imple-
mentation of the Gover nment’s Energ y
Emergency Mitigation Action Plan [13]. The
World Bank also provided up to US$5M in
grants for emergency agr icultural farm
inputs and animal husbandry [14]. The FAO
carried out an assessment of the food secu-
rity si tuation as a basis for a coordinated
response by the international community.
The UN organised flash appeals for emer-
gency assistance for both Kyrgyzstan and
Tajikistan, with mixed success.
Concerned by the indications of a severe
crisis , th e UNDP organised a meeting of
intern ational organisations and bilateral
donors in July 2008 to s hare what infor-
mation was available on the crisis situation.
The meeting concluded t hat an in-depth
assessment was urgently needed and under
the leadership of the UNDP a report on the
compound crisis was prepared and released
in January 2009 [15 ]. It concluded that
Kyrgyzst an and Tajikistan are in deed
Water management in Central Asia: state and impact. (2003). In UNEP/GRID-Arendal Maps and Graphics
Library. Retrieved 12:37, February 17, 2009 from http://maps.grida.no/go/graphic/water_management
_in_central_asia_state_and_impact. Cartographer/designer: Philippe Rekacewicz, UNEP/GRID-Arendal
WWW.WATERPOWERMAGAZINE.COM MARCH 2009 17
INSIGHT
threatened by a combination of water and
energy shortage, high food prices an d a
loomin g recession resulting from the
impact of the global economic crisis. The
report noted that:
• Kyrgyztan’s and Tajikistan’s key reservoirs,
Toktogul and Nurek, were respectively
20% and 9% below normal at the end of
2008, with rigorous restrictions on winter
water releases essential if reaching ‘dead
levels’ of these reservoirs (at which electric-
ity production ceases) are to be avoided.
•
Kyrgyzstan and Tajikistan have been hit by
an ‘electric shock’ due to lack of power –
the estimated impact of the winter 2007/8
blackouts amounted to US$280M in
Tajikistan, or 7% of the country’s GDP;
with the extended blackouts especially in
the provinces, but increasingly also in the
capital cities, significant economic losses
are again expected during the current
winter 2008/9.
• Both countries have large population seg-
ments suffering from food insecurity, some
1.5M people in the case of Tajikistan, as a
result of high incidence of poverty and high
local food prices, even after international
food prices receded from the exceptionally
high levels reached during the summer of
2008.
• Fina lly, with their heavy dependency on
minerals and cotton exports and on
migrant workers’ remittances – in the case
of Tajikistan remittances are estimated to
have reached 50% of GDP in 2008 – both
countries are likely to see dra stic reduc-
tions in foreign currency earnings, budget
revenues and household incomes whi ch
will aggravate their already difficult eco-
nomic and social condition.
The impact of this compound crisis is exac-
erbate d by the tense relations between
Tajikistan a nd Kyrgyzst an on the one
hand, and Uzbekistan on the other. Despite
an agreement at the CIS Summit in
October 2008 among the presidents of the
region which was to have facilitated the
provis ion of gas and electricity to
Kyrgyz stan and Tajikistan in exchange for
prudent management of winter water
releas es, Uzbekistan blocked electricity
transm ission over its territory from
Turkmenistan to Tajikistan and also cut off
gas supplies to Tajikistan over an apparent
disagreement on price. In return, Tajikistan
threatened to draw down more of its water
resour ces during the winter and curtail
releases during the s ubsequent s ummer.
Under these circumstances it is critical that
the int ernational community and the b ig
neighbours collaborate in assisti ng the
upstream countries cope with the ecological,
economic an d social crisis that they now
face. This requires assistance in addressing
the underlying issu es that cause their vul-
nerability to recurring droughts (limited
power generation capacity, inefficient water
and energy use, weak in stitutions), and
engagement in a high level diplomatic dia-
logue to ensure the current tensions between
upstream and downstream nei ghbours do
not lead to tit-f or-tat reactions th at could
turn into interstate conflict.
H
ONEST BROKERS REQUIRED
Centra l Asi a lie s at the hub of a rapidly
integrati ng Eurasian super-cont inent, sur-
rounded by some of the biggest and most
dynamic economies on the globe. Its sta-
bility and prosperity is critical not only for
C
entral Asians but for all of Eurasia and
the rest of the world . Central Asia faces
many opportunities and constraints.
Among th em the re gion’s water and
energy resources stand out because of th e
great potent ial th at the y repr esent, but
also because of the complexi ty of the chal-
lenges that they pre sent to each of the
countr ies, to its neighbours and to th e rest
of the world. It is essential that Central
Asian countries promptly address both the
long term development opportunities and
the short term t hreats of the compound
crisis in which water and energy scarcity
plays a huge role. But they cannot do it
alone. They need the hel p of their neigh-
bours as well as the help of the wider
internati onal community.
The international organisations – the
United Nations and the multilateral devel-
opment banks, including the World Bank
–
have a special r ole to play, because of
their technical and financial capacities and
their a bility to act as honest b rokers.
Despit e all the pressing cha llenges else -
where in the world, it is important that the
international community pay close atten-
tion to the developments in Central Asia,
e
specia lly the developments in the water
and energy domains .
Johannes F Linn is Senior Fellow and
Executive Director of the Wolfensohn
Center for Development at The
Brookings Institution in the US, and a
Special Adviser for the Central Asia
Regional Economic Cooperation
Program (CAREC). He previously
served as Vice President for Europe
and Central Asia at the World Bank.
Email: jlinn@brookings.edu
Footnotes
[1] For the purpose of this article Central Asia is defined to include Kazakhstan, Kyrgyz Republic,
Tajikistan, Turkmenistan and Uzbekistan. The population of the five countries combined is about 60
million. For an overview of the regions economic, social and political conditions see UNDP, Central Asia
Human Development Report, New York, 2005
http://europeandcis.undp.org/poverty/show/300BDC00-F203-1EE9-BE944F24EDFC09CE .
[2] Konstantin Parshin, ‘Tajikistan: government harbours hydropower dams, EurasiaNet, June 4 2008.
http://www.eurasianet.org/departments/insight/articles/eav060408.shtml.
[3] See Eurasian Development Bank, Water and Energy Resources in Central Asia, Industry Report,
April 24 2008.
[4] Eurasian Development Bank, op. cit. See also John Magrath, Glacier Melt, Oxfam Policy Paper
January 2004 http://www.oxfam.org.uk/resources/policy/climate_change/glacier_melt.html
[5] See UNDP, Central Asia Human Development Report, op. cit.
[6] For a good summary of prior feasibility studies for Rogun see International Water Power and Dam
Construction (May 2008), Onwards and Upwards, Volume 60, No 5, pp30-34.
[7] See UNDP, Central Asia Human Development Report, New York, 2005. Kazakhstan announced in
2008 that it will proceed with the construction of Kokserai reservoir; see Joanna Lillis, Central Asia:
Water Woes Stoke Economic Worries, Eurasianet, 28 April 2008
http://www.eurasianet.org/departments/insight/articles/eav042808.shtml
[8] Eurasian Development Bank, op. cit.
[9] On February 3, 2009 Russia reportedly agreed to provide Kyrgyzstan $2 billion in financing for the
construction of Kambarata; see
http://www.rferl.org/content/Kyrgyzstans_Multivector_Foreign_Policy_Unravels/1491581.html. Tajik-
Russian negotiations about Russian financing for Rogun broke down in 2007 since Tajikistan would not
agree to give up control of this key national asset. During a recent visit to Uzbekistan, Russian
President Medvedev announced his country’s support for the Uzbek position that no upstream
development of hydropower resources should proceed without full consultation and agreement of the
down-stream neighbours; see http://enews.ferghana.ru/article.php?id=2497.
[10] See Stimson, The Indus Water Treaty: A History, 2007
http://www.stimson.org/?SN=SA20020116301
[11] http://www.fao.org/world/regional/REU/projects/TCP-TAJ-3104%20(E)-en.pdf
[12] http://www.usaid.gov/locations/europe_eurasia/press/success/2008-03-03.html
[13] http://web.worldbank.org/WBSITE/EXTERNAL/NEWS/
0,,contentMDK:21754640~pagePK:64257043~piPK:437376~theSitePK:4607,00.html
[14] http://web.worldbank.org/external/projects/main?pagePK=64283627&piPK=
3230&theSitePK=40941&menuPK=228424&Projectid=P112157
[15] UNDP, Central Asia Regional Risk Assessment: Responding to Water, Energy, and Food Insecurity,
Regional Bureau for Europe and CIS, New York, January 2009
I
WP
& D
C
18 MARCH 2009 INTERNATIONAL WATER POWER & DAM CONSTRUCTION
CONSTRUCTION
open air excavation works for the dam body and appurtenant struc-
tures. The design aspects of the project, together with a general layout
plan, were detailed in an article published in the July 08 issue of
IWP&DC [1], and will therefore not be covered in this paper.
G
EOLOGICAL AND GEOTECHNICAL PARAMETERS
The geology at the Deriner site is mainly composed of granodiorite
intruded by diabase dykes, which are generally very suitable for the
foundation of an arch dam. Nevertheless, the upper layer of the rock
is decompressed and heavily jointed, which means that it has to be
excavated so as to ensure sound rock for the dam foundations.
Since both main rock types, Diabase and Quartzdiorite, are quite
homogeneously distributed over the site and show more or less sim-
ilar properties of intact rock, there is no need to specifically take into
accoun t th e lithology in defining the design values of intact rock
parameters.
Unconfined Comp ressive Strength results on dry rock samples
show mean values of !
ci
= 120 MPa for the Left Bank and !
ci
= 80
MPa for the Right Bank. The modulus of elasticity of the intact rock
is worth E
Si
= 65 GPa.
Despite the relatively favourable strength and deformation para-
meters of the intact rock, the behaviour of the rock at the Deriner
site is mostly controlled by the properties of the discontinuities since
their spacing can be considered as close with respect to the scale of
the structural elements to be built.
Five main joint sets have been identified at the site: Joint sets A
and B are dominant and represent conjugate sets of fractures; thus,
they intersect at right angles. Their spacin g ranges from 1 to 5m.
Joints C and D are subordinate, but can still be observed at most
locations and their spacing ranges from 10 to 15m. Fractures from
joint set E are very rare and the spacing is over 20m.
Figure 2 shows the stereographic projection of these five joint sets
for each bank. The dam a xis corresponds to the valley axis. The
strength of the rock mass can only be considered as isotropic when
it is heavily jointed, i.e. when it exhibits several joint sets and low
joint spacing, or when it is intact, i.e. when no joint crosses the mass.
With five joint sets and joint spacing orders of magnitude smaller
than the structures it will support, the rock mass at the Deriner dam
site can be considered, at a large scale, as homogeneous and isotrop-
ic. Figure 3 illustrates the numerous joints existing at Deriner site.
D
ERINER DAM is a double-curvature arch dam located
on the Çoruh River in Northeastern Turkey. With a height
of 249m and a volume of concrete of 3.5Mm
3
, it will be
the highest arch dam in Turkey once complete in 2011.
The installed capacity of the powerhouse will be 670MW (with four
Francis turbines) with annua l generati on of 211 8GWh. State
Hydraulics Works (DSI) of Turkey owns the project, with construc-
tion work being carried out by a consortiu m led by Turkish con-
tractor ERG.
In 1997, Stucky Ltd, a Swiss consultant, was appointed to bring
technical assistance to the contractor. Firstly the company conduct-
ed, under the direction of DSI, a full review of the final design pro-
ject from 1991, and then performed a complete detailed design of
the dam and its appurtenant structures. A number of measures were
introduced to improve safety and reduce construction costs and time.
Excavation began in October 2000 on the Left Bank. In August
2005, all open air excavations for the dam foundation were com-
pleted. The total volume of excavated material amounts to 8.7Mm
3
.
Figure 1 shows the project site before and after excavation.
On 11 December 2005, the mass concrete works for the dam
began. These works are currently ongoing with the project expected
to be complete by the end of 2011. This article provides details of the
Open air excavations at Deriner dam
C
C
N N
E
E
D
D
A
A
B
B
D
a
m
a
x
i
s
D
a
m
a
x
i
s
Joint sets-Left bank Joint sets-Right bank
Olivier Muller provides details on the excavation works carried out as part of the
Deriner arch dam project on Turkey’s Coruh River
Figure 1 – Views before excavation works (May 1999)
and after completion of excavation (November 2005)
Figure 2 – Stereographic projection of the five joint sets for the left and right
banks, with dam axis
Direct shear tests on joints were performed and three properties
have been measured: the peak shear strength; the residual shear
strength; and the reverse residual shear strength. Based on the results,
the average peak friction angle on joints is 44°, the residual friction
angle on joints 37° and the peak cohesion about 0.5 MPa. The Rock
Mass Rating (RMR) ranges from 45 to 60, which classifies the rock
mass as ‘fair rock’.
From empirical studies as well as in-sit u laborato ry tests, rock
mass parameters have been widely discussed throughout the project.
Finally for the rock mass, the overall modulus of deformation rec-
ommended at the time of the final des ign is E
sm
= 9 GPa and the
Mohr-Coulomb failure parameters are !
pm
= 35° to 40° and c
m
=
0.15 to 0.20 MPa.
D
ESIGN OF THE EXCAVATED SLOPES
The excavation work has been carried out respecting the following
geometrical principles:
1. Berm heights: 15m
2. Slopes of berms: 1/5 (Horizontal / Vertical)
3. Berm widths: 5m
Excavations, which start from el. 578 at the Right Bank and from
el. 620 at the Left Bank, extend down to el. 144. It means that the
natural slopes are excavated on over 430m height for the Right Bank
and nearly 480m for the uppermost point at the Left Bank. Twenty
nine berms at the Right Bank and 33 berms at the Left Bank have
been excavated.
As a general rule, two types of stability analyses for the surface
excavations have been carried out throughout the project site:
a) Global stability
Global stability of the excavated slopes is verified, and proper sup-
port designed, over multiple berms height assuming two-dimen-
sional and prismatic behaviour. The general method used to study
the global stability is based on the limit equilibrium of unit thick-
ness rock mass slices.
Failure through the rock mass along the most unfavourable hypo-
thetical plane is considered for each cross-section. For this analysis,
WWW.WATERPOWERMAGAZINE.COM MARCH 2009 19
cohesion of the rock mass is always taken into account.
In some situations, the relative orientation of one or several joint
sets with respect to the natural/excavated slope is unfavourable. In
these cases, failure along joints is also analysed, taking into account
the joint shear strength parameters.
Global toppling failure mode is also considered. The results show
that, according to the very low cohesion required to ensure stabili-
ty, this mode of failure is ruled out for most of the excavated slopes.
Geomet rical a s we ll a s shear strength parameters have been
adapted throughout the project according to observations made on
site during the first excavations. An assessment of global stability
has been carried out on numerous cross-sections of the Right and
Left Banks, taking into account different rock mass parameters ,
s
hear strengths parameters on joint and exact geometry. This global
stability analysis generally results in the installation of active pre-
stressed anchors.
The global stability analysis is a large-scale analysis (several tens
of meters high), which implies that the sliding plane is deep inside
the rock mass (more than 10m), making it impossible to use passive
anchors to increase the sliding resistance. Only pre-stressed anchors
are considered if required by the global stability analysis.
Figure 4 represents an example of a global stability analysis con-
sidering failure within the rock mass and failure along joints C.
b) Local stability
Local stability is verified and proper support designed over a single
berm height assuming a three-dimensional (wedge) behaviour. The
CONSTRUCTION
Below: Figure 3 – Picture of the rock mass at the right bank with the overflow
spillway inlet in the centre at elevation 360m asl
Right: Figure 4 – Right bank – failures assumptions for global stability
analysis during excavation;
Failure surface for failure
along joints C (mode 1)
Failure surface for failure
within the rock mass (mode 2)
578
476
50º
33º
74º
S
e
t
A
S
e
t
C
general method used to study the local stability is based on the limit
equilibrium of three-dimensional rock wedges bound by two joints.
Local stability generally induces a light supporting system on
almos t every berm, with passive anchors (rockbolts), weld me sh
and shotcrete.
The local stability analysis is a small-scale analysis (usually 10m
corresponding to one berm h eight), taking into account the joint
sets. No cohesion on the joints is considered in the computation,
as this figure is very uncertain and scattered around its average
value, and greatly influences the computation results. This analy-
sis results in both active and passive anchors, with priority for pas-
sive anchors (rockb olts, easier to pl ac e and less expensive th an
pre-st ressed anchors). Active anc hors are designed in extreme
cases, where the stability of the rock surface cannot be ensured
with rockbolts only.
Generally, four different load cases are considered for the global sta-
bility analysis:
1. Structural Loads – in addition to the weight of the potential
rock wedge, these lo a d s are the loads imposed by any structure
which a ffects the stab ility of the slope (for example, the over-
flow spillwa y inlet structure weight whe n checki ng the stabili-
ty of the slope located at the downhill side).
2. Rapid drawdown of the reservoir – it is assumed that some
water pressure will build u p on the failure plane if the reser-
voir is drawn down to the minimum operating level relatively
rapidly. This is for the following reasons: g routing is under-
taken in the slopes for passive grouted anchors and a ctive pre-
stressed anc ho r s . The fault planes are expect e d to have a lower
pe rmeability than the normal r ock mass. Th ere will pos sibly
be some redu ced ef ficiency of the installed dr ainage measures.
This parti cular load case is difficult to qua ntify due to the
number of uncertainties, such as permeabil ity of the failure
plane, soft ening effect of water on the fau lt pro perties, flow
conditions within the fault, and water recharge from the moun-
tain side, which could have a significant impact on the final
design value. A value of 30% of the change in water pressure
during drawdown is applied to the fault planes as agreed with
the Owner.
3. Earthqu a k e – the operating basis earthquake (OBE) horizontal
acceleration of 0.2 g is assumed.
4. Reservoir level – for cross-sections below the dam c rest (397m
asl), the rese rvoir operating levels is considered with the fol-
lowing cases: normal operating level ( 392m) and minimum
operating level (34 m ).
The stability design takes into account a maximal factor of safety of
1.5 in general when only structural load case applies, and a mini-
mum factor of safety of 1.0 in general when considering that all
loads occur at the same time.
E
XCAVATION AND SUPPORT
The first phase of excavation is the removal of the decompr es s e d
rock mass, which is not suitable for use as aggregate for concrete
production. The thickness of this layer is observed to be from 5 to
10m, parallel to the natural rock surface. The extremely weathered
layer close to the surface makes it impossible to apply a regular blast-
ing pattern. Therefore dozers or excavators (generally back-hoes)
are used for excavation of the overburden.
The second phase of excavation consists of the large mass exca-
vation between the first phase and the foundation. The most impor-
tant point in this excavation is to provide a smooth geometry and
not to disturb the design excavation line in the interfaces with the
berms and avoid damage to the foundations.
Drilling and blasting using the pre-splitting method has been
undertaken at the Deriner site for the majority of the excavations
since the start of the works. However, the first sections of the dam
foundation were excavated using a different method – a controlled
blasting method which, as applied on site, has been observed to yield
less favourable results. Pre-splitting on the dam foundation below
el. 297m on the Left Bank and el. 342m on the Right Bank showed
improvements in the excavation method. Figure 5 shows the rock
surface of half a berm just after blasting.
Where found necessary, pre-stressed anchors are installed. The
nominal load T
n
of the prestressed anchor is set to 1860 kN and
therefore induced a Lock-off Load T
0
of 2050 kN and an ultimate
Load T
u
of 3350 kN, which induce a material factor of safety of
1.80, according to the normative reference EN 1537. Suitability tests
performed at the very beginning of the project indicate that a bond
length of 8m is adequate for this kind of rock. Figure 6 shows the
installation of prestressed anchors on the Right Bank.
The tension in all anchors is checked at one, 30 and 100 days, by
means of the tensioning jack. If the increase / decrease in the load of
20 MARCH 2009 INTERNATIONAL WATER POWER & DAM CONSTRUCTION
CONSTRUCTION
Above: Figure 5 – Excavation at the Right Bank at chainage 310m between
elevations 420 and 427m asl
Right: Figure 6 – Installation of pre-stressed anchors in December 2004 on the
Right Bank at el. 345 and 348.5m asl; Far Right: Figure 7 – Current view of
the left bank (20 February 2009)