'Dam Busters' - 60 years ago, the Möhne Dam was bombed

R.A.F. breach giant dams
New blow at Ruhr industries
Tuesday May 18, 1943

Power stations and bridges to be swept away
Floods reported to be `spreading fast'

Heavy blows of a new kind were delivered against Germany's war industry early yesterday, when a force of Lancaster bombers breached the enemy's three greatest dams at the Mohne, Eder, and Sorte reservoirs, which together control more than two-thirds of the water storage capacity of the Ruhr.

Aerial reconnaissance shows that the Mohne Dam has been breached over a length of 100 yards, that water is pouring down the Ruhr valley, that railway and road bridges have broken down, and that hydro-electrical power stations have been destroyed or damaged. The Eder, which controls the head waters of the Weser and Fulda valleys and operates several power stations, is also breached. Photographs show the river below in full flood. Floods are also rising in the Dortmund area, 30 miles away.

Picked Lancaster crews had been training in secret for the operation and only about half a dozen people in Bomber Command knew anything about it.

The dams were specially constructed to meet the enormous demands on water made by the Ruhr factories. The 134,000,000 tons controlled by the Mohne represents 30,016,000,000 gallons while the capacity of the larger Eder is 45,218,000,000. What these figures mean may be gathered from a comparison with the daily normal flow of the Thames at this time of year. At the height of the river's flow only 2,500,000,000 gallons pass down the Thames daily.

How attack was planned

A partial reconnaissance of the Ruhr Valley and the district near the Eder dam in daylight yesterday showed that the floods caused by the attacks on the three dams are spreading fast, said a report from the Air Ministry News Service last night.

The waters are sweeping down the Ruhr valley. Railways and road bridges are broken down, hydro-electrical power stations are destroyed or damaged, and a railway marshalling-yard is under water.

The floods from the Eder dam, breached in two places, are already as great as the floods in the Ruhr valley, but the country here is flatter and the water is likely to spread over a greater area.

Picked Lancaster crews had been chosen for the operation and had been training for it for many weeks. They worked in complete secrecy on a bomber station which, as far as possible, was cut off from any contact with the outside world. Only about half a dozen other men in the whole of Bomber Command knew what they were doing.

Effects of flood

In the early hours of yesterday, when the weather and light were exactly right, they carried out the operation. The purpose was to subject the whole Ruhr valley to almost as severe an ordeal as it has undergone by fire in the last three months, and to do the same for another industrial area farther east. These picked men, under the command of Wing Commander C.P. Gibson, D.S.O., and bar, D.F.C. and bar, went out to attack the three huge water barrage dams - two of them on the rivers Mohne and Sorte, tributaries of the River Ruhr, and the other on the River Eder.

The Lancaster crews knew how much depended on their success or failure. The opportunity might never come again, and it was an opportunity, as they knew, of doing as much damage as could be done by thousands of tons of bombs dropped on many nights running.

The Mohne and Sorte dams control some 70 per cent of the water catchment area of the Ruhr basin. Before they were built the Ruhr was always apt to run short of water in a dry season - the Sorpe reservoir alone takes two or three years to fill. If the reservoirs were suddenly emptied the floods that resulted would be as serious as the subsequent shortage of water. A total of 134,000,000 tons would pour out from the Mohne reservoir alone. The effects of both flood and shortage of water might be disastrous.

There are 300 and more waterworks and many pumping stations in the Ruhr valley. Interference with these would very seriously affect the supply of water for industrial processes. Thermo-eletric power stations would have no cooling water and many hydro-electric power stations along the Ruhr valley would be affected. River and canal traffic is of vital importance to all the industries of the Ruhr. With these dams gone and water pouring from the deep lakes behind them, the River Ruhr itself might become unnavigable and water level in the canals could not be maintained. Finally, there is a possibility that important industrial areas in the Ruhr would themselves be flooded.

Before the construction of the Eder dam - the reservoir is the largest in Germany and contains 202,000,000 tons of water - the rivers Eder and Weser regularly caused serious floods. The breaking of the dam would probably flood parts of Kassel, including important industrial areas, as well as of towns beyond. Agricultural districts along the Weser would also be inundated. Several hydro-electric stations would be affected, four of them of considerable value to the electrical supply of the whole district.

As with the two other dams, floods would do the first damage and the loss of the water the rest. The primary object of the reservoir is to store water to compensate the River Weser for water taken from it for the huge Mittelland Canal, the main artery for water-borne traffic from west to east and the link between all the main navigable rivers west of Berlin. Without the reservoir there would not be enough water for both the Weser and the Mittelland Canal. Navigation on one or the other and probably on both would be seriously affected.
from: Guardian Century