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Workshop “Water Security for Bulgaria”

Sofia, Bulgaria, 2017

Rehabilitation of Dams: Financial instruments, O&M and sustainability

Karen Grigoryan

Dam Safety Specialist, Ph.D.

State Committee of Water Economy

Water Sector Project PIU

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Armenia Dam Safety 1,

## Why the Armenia Dam Safety Project 1 was developed?

1 Three complete dam failures occurred in Armenia in 1974, 1979 and 1994

respectively. Considering the approximate number of dams existing in Armenia in

those years, the percentage of failures (number of failures/ number of existing dams)

can be estimated in the order of 2.1% (1974), 3.5% (1979) and 3.9% (1994).

2 Two aspects are of concern: a) the values are considerably higher than the world-

average value of 0.5% for dams built after 1951 (ICOLD); b) the percentage values

show an increasing trend. From 1994 to 1998, six significant dam-related accidents

occurred that might have as well lead to complete dam failure.

3 All reported accidents could have been avoided if proper surveillance and O&M were

in place

4 No dam is reported to have a functioning instrumentation system and that around

460,000 people are at risk

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Reservoir Conservation (sedimentation management) Prolonging life span of reservoirs by managing sedimentation within a

dam rehabilitation program. Examples?

## Sedimentation management

1 Flashing of sediments by water through the reservoir.

If there is no demand for water, the reservoir may be emptied in winter.

2 Construction of reservoirs on off-stream ravines instead of main river bed

3 Flood transformation through a lateral canal;

4 Construction of transverse bottom galeries in the upstream of the reservoir

5 Construction of bottom outlets in the dam

6 Construction of pounds upstream in the river.

7 Creation of capacities for collection of the sediments

8 Rational water regime

9 Planting of vegetation in the catchment area

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Ajgedzor Dam

O&M financing in Armenia

The organization responsible for O&M of dams in Armenia is called "VorogumCJSC" (Water Supply Agency - WSA). It operates 14 major state-owned reservoirs, large pumping stations and other irrigation infrastructures until the service areas of WUAs.

WSA is a state-owned entity and has its budget. The revenues of WSA are generated from the sale of bulk water to WUAs and other water users.

The deficit is covered by the State.

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Activities Financed under DSP and IDSP II

Activity DSP

DSP Savings and

Emergency Fund

IDSP II

Not Needed or

Competence of Agencies other than

WSA

TOTAL

Technical investigations 86 0 1 0 87Rehabilitation 20 7 47 13 87Control measurement equipment and instrumentation plans

20 7 47 13 87

Operation and maintenance equipment and O&M plans

20 5 55 7 87

Emergency preparedness plans (EPPs) 20 35 1 21 87Equipment for EPPs implementation (safety equip.)

20 3 56 8 87

Upgrade safety of access roads 0 0 16 0 16

Dam Safety Project Components and results

Components

A. Rehabilitation of 20 primary irrigation dams:

A. 1. Repair works on critical parts affecting dam safety

A. 2. Operation and maintenance: Incremental cost of operation and maintenance

B. Dam safety monitoring:

B. 1. Capacity building: Strengthening the institutional capacity of the Dam Maintenance Enterprise

B. 2. Emergency warning system

B. 3. Investigations and emergency interventions on 53 secondary irrigation and 6 energy dams

Results Improved slops stability, increased spillway

capacities, repaired bottom outlets, excluded leakage and erosion.

O&M Plans were prepared, documenting operation, maintenance and surveillance. EPP were prepared for any dam whose failure could be expected to result in loss of life.

Provided Instrumentation and monitoring devices, early warning systems, energy supply, short wave radio, stations, workshops, watchman houses

The incremental O&M costs include DME incremental staff, central and regional offices, transport and utilities.

Safety investigations done for all remaining dams. A limited provision is made to create an emergency fund to allow DME to intervene in cases where further deterioration of any of these dams poses an imminent threat to human life.

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IDSP II Project components and results

Components

Rehabilitation of Dams:

Dam Safety Sustainability:

Improvement of access roads for 16 dams to enable timely access and implementation of safety measures in case of emergency.

Results

This component was provided for: (i) engineering design of rehabilitation activities for 29 dams and preparation of an emergency preparedness plan for the Yerevan Lake Dam, (ii) implementation of rehabilitation works on 47 dams (29 dams for which designs are provided for under this project and 18 dams for which designs were already prepared under DSP); (iii) construction supervision in the course of the rehabilitation of the 47 dams; (iv) installation of monitoring equipment devices on the 47 dams.

provision of technical assistance and equipment to WSA to: (a) design an integrated telecommunication network for all dams, (b) prepare the necessary regulations and operational procedures to guide all parties involved in management of dams, (d) retain the services of an independent dam safety expert for the duration of the project, (e) provide training in O&M practices for operational staff involved at dam sites etc.

Most critical sections for 16 access roads for 16 dams were rehabilitated.

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The benefits from rehabilitation of 27 dam sites.

Most important is the safety risk reduction for 360,000 people living downstream of highly risk dams. 460,000 people in Armenia live in inundation areas. Considering all dams in the country, 1 out of 10 people in Armenia is under potential risk.

Risk reduced for potential flooding and loss of 34% of total irrigated area in Armenia through securing water supply to an area of 68,000 ha, which produces annual net farm income of 35 mln $US.

Risk reduction of potential destruction of 78,000 homes and damage to over 2 bln. $US worth of roads, irrigation structures, and other public structures and enterprises. The damage in the case of failure of only one dam (Azat Dam) has been estimated 800 mln $US.

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The benefits from rehabilitation of 47 dam sites.

A) Reduced risk for 118,500 people living downstream of the dams to be rehabilitated.

B) Reduced risk of potential flooding and loss of yield on 64,350 ha of irrigated land.

C) Reduced risk of potential destruction of 1,090 private houses and various other quantities of roads, public utilities, other infrastructure, and industrial enterprises.

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Phases of dam safety

The design phase when engineers and geologists conceive on paper the specifications for how the dam should be constructed;

The construction phase when the designers and builders of the dams provide operators with documents, which describe how the dam should be operated by means of “Operation manuals” and as-built drawings.

The Operation and Maintenance (O&M) phase which is the longest period in dam’s lifetime. During this period the operators should prepare Standing Operating Procedures (SOP) for use in the continued O&M of the dam. During the operation period new equipment or features may be produced which should be added to keep the operation procedures up-to-date.

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Jacobs GIBB method considered in Armenia during dam investigations

Static instability

Dynamic instability

External erosion

Internal erosion.

The probability of failure comprises two factors:

the probability of an event;

the probability of the event resulting in dam failure.

Thus the overall risk is calculated according to following formula:

Risk = (probability of an event) (probability of adverse response given event) (consequence given response)

While assessing consequences of dam failure the top priority should be given to human losses. There are many factors affecting loss of life (LOL):

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Risk Assessment

The most frequently applied method, which is adopted in Canada, UK and US is as follows:

The method comprises identification and assessment of the following 3 elements:

identification of failure modes;

comparative assessment of probability of failure;

comparative assessment of consequences of failure;

In other words you should define:

how could failure occur;

how likely is it;

what would happen if it did?

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Major issues

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The lack of funding still is the major issue.

the lack of funds entails insufficient allocation for O&M purposes;

as a result, the technical state becomes endangered.

The first two are directly impact the safety.

There are issues which have no direct relation with safety at a first glance, however they impact it.

The salaries of operating staff is too low, the staff turnover is high.

There are cases inefficient dam management. For example, larger than required volume of water is released from the reservoir before the spring, and as the reservoir is not filled afterwards.

The fee collection rate in WUAs has dropped for various reasons.

There is a shortage of qualified and (and general) qualified staff, in particular of hydraulic engineers.

Continuation and sustainability of the Projects

The Projects Implemented by the GoA are as fallows:

The Irrigation Rehabilitation Project aimed to rehabilitate the most critical parts of Irrigation System in Armenia;

Irrigation Development Project aimed to implement except rehabilitation activities institutional activities, Water Low, etc.

Irrigation Rehabilitation Emergency Project aimed to rehabilitate the most critical parts of the system and make rehabilitation works in the period of world global crisis.

Dam Safety 1 and Dam Safety 2: were investigated all 87 dams and rehabilitation activates on 47 dams:

Irrigation System Enhancement Project - ongoing.

Irrigation System Modernization Project - ongoing

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