The evolution of the fluvial area in the western part of the Netherlands from 1000-1300 AD

Abstract

The Dutch fluvial area changed drastically during the period 1000-1300 AD, mainly due to human influence. Four topics are discussed: 1. On the basis of new radiocarbon datings and calculations of the rate of sedimentation it is concluded that the River Lek came into existence about 2000 years ago; 2. The silting up of the Kromme Rijn near Wijk bij Duurstede did not occur before the second half of the eleventh century. A dam was constructed in the river in 1122 AD; 3. The present rivers have a steeper gradient than recently abandoned meander belts. Changes in gradient are shown to be complex and not necessarily related to changes that occurred between 1000 and 1300 AD. 4. During the period 1000-1300 AD the main rivers were embanked; smaller branches were dammed. The embankments made it possible to reclaim the low-lying peat areas.