Monday 4 April 2016

Saddam dam

I'm given to understand that you can't sue the county council if you trip-and-fall while walking along the grassy margin of the road; but if they undertake to make your life easier by making a footpath and you trip on some irregularity in the paving THEN you can make a claim for mental anguish or a grazed knee.  It seems a bit unfair on the council until you reflect that we should take responsibility for the consequences of our actions.  The long-dead Dutch engineers who build the barrage that created Situ [Lake] Gintung in 1933 might have ground their teeth in frustration when their handiwork failed on the night of 26/27th March 2009.  The earthen dam had been created to service local paddy fields near Cirendeu in Indonesia. At 16m high and 250m long, with water backed up along two river valleys, the dam held a reservoir of about 2 million cu.m = tonnes of water.  It was, therefore about the same size as the lake above Dolgarrog in N Wales that failed catastrophically in 1925. As with Dalgarrog, the Situ Gintung failure was preceded by a sustained deluge of rain. The dam failed at the worst possible time in the middle of the night and 100 people died when a wall of water destroyed their homes. One of the ironies was that the paddy fields had long since been converted into housing lots because the district is only 10km S of Jakarta's Special Capital Region. A number of officials were cited for negligence but you can bet that they never received sufficient funds to carry out the necessary maintenance.  The dam has since been restored and is visible on Google Maps.  So far so small: 16 poor Welsh people and 100 Javanese don't weigh much in the scales of catastrophe. And heck, they're dead, there's not much we can do about it except build the new Gintung dam stronger and with better spillways.

Some dams are big! They make an obvious impact on the landscape and a case can be made that they are useful: for regulating water supply for rice paddies or tapping the moving water to drive turbines to make electricity.  The Shannon Scheme and the dam at Ardnacrusha was as much a political statement about Independence from the Brits, and take her place among the nations of the earth, as it was about servicing the nascent state of Ireland with electricity.  The idea for damming the River Tigris North of Mosul had been on the cards since at least 1953. With each change in regime, successive international consultants were called in at international consultant prices as the Tigris Dam got political traction: 1953 Alexander Gibbs; 1956 Kolijan American; 1960 Harza; 1962 Soviet Technoprom; 1965 Amitranvoima; 1972 Geotehnika; 1974 Soletanch; 1978 Swiss Consultants Consortium.  If Iraq is anything like Ireland, the fees for the consultants could have built the dam twice.

Actual works didn't start until the 1980s as part of Saddam Hussein's Arabification of the predominantly Kurdish North of the country.  Hochtief Aktiengesellschaft, a German/Italian consortium got the go ahead to  break ground in 1981.  As the bed 'rock' was gypsum which is only harder than talc on the Mohs scale of hardness, and is also water-soluble, the first step was to grout the base of the projected dam. The engineers recommendation was dismissed as too expensive and time consuming and after a slip-slop blanket grouting, construction proper began.  The dam was completed by 1984 and is massive: 113m high in the centre and 3500m wide, it is holding 10 billion tonnes of water - that's a reservoir 5000x bigger than Situ Gintung.  The dam, however, is more or less of the same earth-core construction. In Indonesia or Wales, you have to be primarily concerned with excessive rainfall over a short period of time; in Northern Iraq the main concern is seasonal snow melt in the mountains of Turkey which is where the Tigris and its tributaries rise.

Going round the news at the moment is a story that the intrinsically under-engineered Mosul Dam is under imminent threat of failure.  The US Army Corps of Engineers say it is at "significantly higher risk" of failing than previously thought as more and more untreated voids are becoming apparent in the fabric of the dam or its 'foundations'.  Because the job wasn't done properly (or abandoned as futile) at the start, the operators are committed to pour concrete into voids until the end of time or the dam fails.  Oh, and there's a war on!  ISIL captured the dam in 2014 and the routine relentless maintenance was put on hold so that everyone could engage in compulsory Salah five times a day. If the dam fails 10 billion tons of water will travel downstream as a wall, reaching Mosul 4 hours later and Baghdad after a couple of days. The water will still be 4m deep in Baghdad. As with Egypt and the Nile, pretty much the whole population of Iraq lives in the river valleys of the Tigris and Euphrates. Pessimists say that a sudden collapse would kill 1 million people, optimists claim only half that. !?

No comments:

Post a Comment