8/7/2019 Dam safety [Compatibility Mode]

1/17

Experience of Instrumentation andPerformance of Mtera Dam

THE 22nd AFRICAN HYDRO

SYMPOSIUM

Aballah .O Ikwasa

Welcome to the presentation

15th to 17 th September 2010

ARUSHA, Tanzania

Hydro Power plantCivil Engineer

Mtera Hydro Power

Plant

The 22nd African Hydro

Symposium 15th to 17th Sept.20101

8/7/2019 Dam safety [Compatibility Mode]

2/17

Out line of presentation

Introduction Dam safety

The 22nd African Hydro

Symposium 15th to 17th Sept.20102

Importance of Regular Inspections of Dams Dam Safety Monitoring for Mtera Dam Monitoring Instruments Installed at Mtera

Dam Conlusion and Recommendation

8/7/2019 Dam safety [Compatibility Mode]

3/17

Introduction

Mtera dam was part of theGreat Ruaha Power Project

The 22nd African Hydro

Symposium 15th to 17th Sept.20103

The dam was constructed toserve as a water magazinefor operation of

Mtera(80MW) and Kidatu(200MW)

The dam is the largest one

in the country

8/7/2019 Dam safety [Compatibility Mode]

4/17

Introduction

The dam is located withinRufiji Basin along Great

The 22nd African Hydro

Symposium 15th to 17th Sept.20104

The dam also serves as the

road bridge along Iringa -Dodoma road.

8/7/2019 Dam safety [Compatibility Mode]

5/17

IntroductionMtera Dam Data

Dam Type Concrete buttress dam

Reservoir Volume (million m3) -3200

Dead storage Volume (million m3) -600

Dam height 45m

Crest Length 260m

The 22nd African Hydro

Symposium 15th to 17th Sept.20105

8/7/2019 Dam safety [Compatibility Mode]

6/17

IntroductionMtera Dam Data

Spillway capacity 4000 m3/s

Full supply level 698.50 m.a.s.l.

Minimum Supply level 690.0 m.a.s.l

Reservoir area (km2) at FSL - 660

Reservoir area (km2

) at MSL -200

The 22nd African Hydro

Symposium 15th to 17th Sept.20106

8/7/2019 Dam safety [Compatibility Mode]

7/17

Dam safety

Why do we maintain dams

Recognize problems in their early

The 22nd African Hydro

Symposium 15th to 17th Sept.20107

stages and eliminate them beforethey become complex andexpensive

Minimize risk to others andpotential liability in case of failure

8/7/2019 Dam safety [Compatibility Mode]

8/17

Dam safety

0

50

100East

West

The Events tobe considered

The 22nd African Hydro

Symposium 15th to 17th Sept.20108

s

Qtr

r

Qtr North in dame safetymonitoringincludes:

Natural events

Ancillary Projects

8/7/2019 Dam safety [Compatibility Mode]

9/17

IMPORTANCE OF REGULARINSPECTIONS OF DAMS

Every dam will always deteriorate over

The 22nd African Hydro

Symposium 15th to 17th Sept.20109

time. Dam may either deteriorate slowly or

quickly

Problems that are not recognized andcorrected will always progress

8/7/2019 Dam safety [Compatibility Mode]

10/17

MTERA DAM SAFETY MONITORING

One of the most important activities in a damsafety program is to identify and record any

The 22nd African Hydro

Symposium 15th to 17th Sept.201010

.

8/7/2019 Dam safety [Compatibility Mode]

11/17

MTERA DAM SAFETY MONITORING.

A number of monitoring instruments havebeen installed a Mtera dam to measure:

The 22nd African Hydro

Symposium 15th to 17th Sept.201011

Upstream water levels Leakages

Pore water pressure

Deformations

8/7/2019 Dam safety [Compatibility Mode]

12/17

Table below shows monitoringinstrumentation

S/N Measurement Location Condition

1 Seepage From inspection galleries belowthe ravit dam and

Goodcondition

The 22nd African Hydro

Symposium 15th to 17th Sept.201012

Spillway dam (MW2)

From the down stream part ofthe spillway dam (MW1)

Goodcondition

2 Pore water

Pressure

In the foundation rock below the

dam using stand pipes

stand pipes

are in goodcondition

Below the spillway and gravitydam using manometer

NoManometer

8/7/2019 Dam safety [Compatibility Mode]

13/17

Table below shows monitoringinstrumentation cont..

S/N Measurement Location Condition

3 Up stream Gauge with Automatic Gauge not

The 22nd African Hydro

Symposium 15th to 17th Sept.201013

buttress monolith B6

Water level scales (Gaugeplates) fixed to the frontside of the gravity dam

The scales areworking

Pneumatic water levelinstrument installed at theintake of he power plant

The gauge notworking

8/7/2019 Dam safety [Compatibility Mode]

14/17

8/7/2019 Dam safety [Compatibility Mode]

15/17

CONLUSION AND RECOMMENDATION

Defective daminstrumentation should be

The 22nd African Hydro

Symposium 15th to 17th Sept.201015

Dam designers operatingcriteria is required for

comparison with observedbehavior of the dam

8/7/2019 Dam safety [Compatibility Mode]

16/17

CONLUSION AND RECOMMENDATION...

For hydro power futureprojects, the limiting

The 22nd African Hydro

Symposium 15th to 17th Sept.201016

established and providedto Tanesco beforecommissioning.

8/7/2019 Dam safety [Compatibility Mode]

17/17

THANK YOU

The 22nd African Hydro

Symposium 15th to 17th Sept.201017