Polders in the Wisła Delta

In the Wisła Delta, the surface is between 1.8 metres below mean sea level (at Żuławy Wiślane) and ten metres above mean sea level. Therefore, there are several polders in the delta, with a total surface area of around 170,000 hectares. The area deeper than 2.5 metres below mean sea level is called the Low Fens. Based on the level of the surface, three types of areas are distinguished:

• the area below mean sea level, 45,000 hectares;
• the area with a surface between 0.0 to 2.5 metres above mean sea level, 72,000 hectares;
• the area higher than 2.5 metres above mean sea level, 53,000 hectares.

The excess water from the higher area can be discharged by gravity for most of the year. The discharge of excess water from the other areas is by pumping stations. The polder areas cover a total of around 120,000 hectares with a discharge by 115 pumping stations.

The first land reclamations in the Wisła Delta took place in the fourteenth century. From 1740 onwards, at the initiative of the Prussian King Frederick II, polders were constructed on a large scale based on the Dutch land reclamation model. Dutch colonists were also involved in several of these land reclamations. A number of them were Mennonites. In an article from 2006, Zbigniew Chodila describes, among other things, the Dutch involvement in land reclamation in the Wisła Delta, distinguishing three periods:

• 15th – 16th century. A total of 233 settlements in the marshes around Gdansk and along the Wisła;
• 1660-1795. 977 settlements, some of which in the Wisła Delta;
• 1795-1864. 300 settlements, some of which were in the vicinity of Gdansk.

If you fly from the Netherlands along the coast of the Baltic Sea to the East, you will see Germany, Poland, the Russian enclave of Kaliningrad, Lithuania, Belarus and Russia. You will then see very large differences in the parcelisation, with Poland standing out because of the many very small parcels compared to the surrounding countries and areas. One of the reasons for this is that in the former German Democratic Republic and Soviet Union there was - and often still is - very large-scale agriculture on collective farms and sovkhozes. Even during the communist era, however, Poland never succeeded in introducing the large-scale agriculture system and the small-scale parcels continued to exist. Incidentally, this also resulted in the many old dikes in the Wisła Delta.

In 1978, I visited the area together with a colleague from TU Delft during a study tour. The Dutch influences were indeed visible in some places in the buildings. About ten years ago a Polish colleague spoke to me about how we prepared and implemented land consolidation in the Netherlands. They wanted to improve the water management systems and the flood protection in the Wisła Delta, but due to the small-scale farm plots and areas that was still a very big task. In fact, a large-scale land consolidation was actually necessary first, which meant that larger plots would have to be created in a different way than in the communist era, with water management and flood protection tailored to them.

I have not flown over the Wisła Delta recently, but Google Earth shows that in many places in the delta there are still small plots. So it will take some time before the desired improvements will be achieved.