The lock at Iezumasyl and the De Dongerdielen pumping station tell the story of centuries of living with and managing the waters of Fryslân.
In 1671 and 1672, a drainage and flood-control lock was built at Iezumasyl to discharge water from the Suderie towards the Lauwerszee. A lock may have existed at this location even earlier. Originally, the Suderie was a tidal inlet and an important waterway connecting the inland area with the sea.
The lock was repaired in 1745 and extensively renewed in 1931. The work was supervised by polder inspector W.D. Booijenga of the Oost- en Westdongeradeel water board. The associated contribution house was also renewed. To improve drainage, the electrically powered De Dongerdielen pumping station was constructed during the same period. The iron lifting bridge dates from 1901. The historic water-management complex at Iezumasyl consists of the lock, pumping station, lifting bridge and control building.
The closure of the Lauwerszee in 1969 changed the function of the area. The former sea dike lost its role as the primary coastal defence, but the lock remained part of the regional water-management system. The lock gates were renewed in 1992. In 2023, the two large gates on the Raskes side were renewed again and a fish passage was added.
The De Dongerdielen pumping station is a restrained yellow-brick building dating from 1931. It has a rectangular design, a pitched roof and a carefully designed interior. Three horizontal screw pumps made by Stork are housed in the machine room. The design is attributed to polder inspector W.D. Booijenga and reflects the sober architectural style of the interwar period.
Originally, the lock keeper operated the pumps when the water level became too high. The installation was later automated. Today, modern systems regulate the discharge of water automatically.
Together, the lock and pumping station form a remarkable piece of water-management heritage. They provide a tangible reminder of how the people of Fryslân have regulated water and shaped the landscape for centuries.
