to the construction The shallow nature of the northern channel permitted a more gradual closure, with the use of a 1.9 kilometre long
cable car system. The advantage of a gradual vertical closure is that flow velocities are limited, resulting in a reduction in the magnitude of
scour holes either side of the dam. Another advantage of the cable car solution was that only a single
pylon was required in the centre of the channel. The cable car system was designed by Rijkswaterstaat in combination with the French company
Neyrpic, and used self-propelled cars and a
one-way system to optimise capacity. A threshold at the base of the dam in the northern channels was poured in 1962, along with a
dike section from Goeree-Overflakkee. The remaining length, of approximately 1200 metres, was constructed by the cable car method. The cableway consisted of two carrying cables, with the last sections terminating at a
turntable, along which the cars could pass from one side to the other. The cables were attached to a fixed anchor point on the north-east side of the closure, which has been preserved as a monument to the construction, and to a tilting counterweight on the opposite side. The units and stone placed by the cars were transported by four steel
hopper barges, being lifted and lowered by the cars. A production rate of 360 tonnes of stone per hour was achieved. The channels were closed using the method of gradual closing, partly because loosely packed sand in the substrate could lead to settlement issues, and partly to gain experience with the use of a cable-way. Using the cable-way stone was dumped on a threshold covered with
fascine mattresses,
polyethylene foil, and
asphalt mastic. The stone dam was built up in this way to 2.5 metres above NAP, after which sand could begin to be sprayed against the closing dam by dredgers, and the dam body raised. By the autumn of 1965, the Grevelingen Dam was completed. ==The Grevelingenmeer (Lake Grevelingen)==