Utrecht: reworking the floodplain

The Roman fort of Traiectum on the Rhine was abandoned in the third century. As a result of rising sea levels and increased flooding most of the area along the large rivers was abandoned, habitation only remained in isolated pockets. Around 650 the Franks build a church within the walls of the former Roman fortress that was quickly destroyed by the Frisians. In 732 the fortress of Uut-Trecht -uut meaning below signifying its position further downstream from that other historic Traiectum ad Mosam now Maastricht- is bestowed on Willibrord the new Archbishop by Charles Martel. This is the real beginning of the present city. After Dorestad fell in 850, Utrecht quickly became the most important city in the northern Netherlands until Amsterdam took this position from 1630 onwards. The settlement received city rights in 1122 and was strategically located near a ford just before the point where the Kromme Rijn (Crooked Rhine) forks into the rivers Vecht and Oude Rijn. This makes Utrecht a true water city as it is situated in the floodplain of the lower Rhine-basin.

The Roman fort of Traiectum nestled in a tight bend of the river Rhine around the year 250.

As a result of silting up the river landscape changed and the main branch of the Rhine became so shallow as to make transport by boat impossible. This prompted the people to dig a new cut from the Vecht to the Old Rhine. This gravening was excavated in 723 in an older Rhine branch. Around 1000 AD the Rhine became very shallow and part of it was dredged between the former Roman fort and the Vecht at Ondiep (Ondiep literally means shallow). Also around the same time a drainage channel was excavated in the peat and clay. This Liesbossche Wetering made it possible to farm the land and also provided the Rhine at Utrecht with more water to prevent further silting up.

Of great importance for the changing drainage situation of the floodplain would be the foundation of the Oostbroek Monastery east of Utrecht on a natural elevation in the peat bog in 1113. The monks dug a 7 km long drainage channel from their monastery tot the Vecht. This Wetering was completed around 1122 and also connected to the Crooked Rhine via the Bisschopswetering (Bishops Drain) that was excavated around 1113 in an old river branch. In the process a new straight cut was created bypassing to old river bends in the Vecht. More or less parallel to this river a second drainage channel the Lisveld was excavated to drain the Lage Weide (literally: Low Meadow). Silting lead to flooding which resulted in the damming of the Kromme Rijn in 1122 near the former Dorestad. This meant that the water levels could be managed much better. With the city rights bestowed on Utrecht in the same year, work started on building city defences. These consisted of earth banks with ditches on each side. On the western side a broad moat was dug to better regulate the flow of water in the Rhine (as a secondary river branch away from the city centre). Also work was started to excavate a new shipping channel to the IJssel near IJsselstein called the Vaartse Rijn (best translated as the Rhine Navigation). For this the Liesbossche Wetering was widened and extended.

Utrecht around 1125 shows a different image of the floodplain.THe Kromme Rijn (KR) bifurcates forming the rivers Vecht (V) and Oude Rijn (OR) near the city of Utrecht; the gravening (1) now being the main flow channel. Other man-made drainage channels include: the Liesbossche Wetering (2), the Oostbroeker Wetering (3), the Voordorper Togt (4), the Bisshopswetering (5) and the Lisveld (6).

The development of a city directly adjacent to its land holdings prompted the Monastery of Oostbroek to start cultivating the peat land more intensively by excavating more discharge  channels, that all run more or less parallel northwards. To improve shipping connections the Nijevecht was dredged and excavated at the end of the twelfth century. Around the same time the Vleutensche Wetering was dug to bypass a shallow, narrow and winding part of the Old Rhine. In the city itself a new canal - Oude Gracht - was dug between the former Roman fort (now the seat of the Bishop) and the Crooked Rhine in 1127, followed in 1165 by the northern part that includes the continuation of the Oude Gracht, the Weerdsingel and the first section of Nijevecht.

Utrecht around 1200 shows the expansion of new shipping links such as the Vleutense Wetering (1), Vaartse Rijn (2) and Nijevecht (3). In the city  the broad moat of the(Stadsbuitensingel (4) connected these new shipping channels and the Oude gracht was excavated in two section, one in the south (5) and one in the north (6). The monks developed new drainage channels suchs as: the Gageltogt (7), the Anthoniestogt (8), Veldtocht (9) and Bureveldse Togt (10).

To improve the transport of peat from the lands of the Oostbroek Monastery the Zwarte Water was dug shortly after 1200, a canal that is named after the black colour of the water. At the same time the narrow stream running through a former river branch is widened and dredged as the Grift. In order to make the area east of the Oude Gracht suitable for urban development the former river bend around the centre is dredged and a new section is excavated in Oudelle around 1260. Around the same time the northern city moat (Weerdgracht) is completed. Twenty years later the Nieuwe Gracht (New Canal) was dug connecting the Kromme Nieuwe Gracht (the old river bend) to the Crooked Rhine. In 1290 a paved road is built as the Steenwech op de Bilt.

The Crooked Rhine keeps silting up further as a result of the dam near Wijk bij Duurstede. This is in part remedied by excavating the southern city moat edging the former flow channel (completed before 1850). The whole city moat is completed before 1380. Later a new cut is necessary. This channel is completed in 1384. The old Rhine Branch is dammed and is hence known as the Minstroom. This stream also gets a direct connection to the Nieuwe Gracht to improve water flow. In 1350 the suburb of Weerd is incorporated into the city walls as Bemuurde Weerd. In 1385 the Alendorper Wetering is dug as a cut linking the Vleutense Wetering with the Old Rhine at Harmelen thus avoiding the narrow winding river and improving accessibly for ships. In 1395 The Nieuwe Gracht is improved and the Plompetorengracht and Drift canals are excavated to improve drainage and make the area better suitable for development.The same year the Lange Vliet and Heycop -both drainage channels- are completed. These are followed by the Bijleveld in 1413 and the Ridderschapsvaart shortly after.

Utrecht around 1425 showing clearly the ongoing cultivation and drainage. The shipping cuts of Zwarte Water (1), Alendorper Wetering (2) and New Rhine (8) keep the city accessible by boat. The drainage situation is improved by digging: the Grift (3), Nieuw Gracht (4), moat (5), Ooststroom (6) and Weststroom (7), Drift and Plompetorengracht (9), Lange Vliet (10), Heycop (11), Bijleveld (12) and Ridderschapsvaart (13).

During the 16th century the fortifications are modernised. In 1544 the new bastions on the westside are completed, followed in 1577 by new bastions on the eastside. The accessibility for ships also needed to be improved. This lead to the excavation of the Leidse Vaart in 1531 with a second section completed by 1545. In the east the new Biltse Vaart was dug around 1633 to improve accessibility from this side. In 1636 the Pall Mall (Maliebaan) was constructed just outside the bastion Lepelenburg. In 1655 the last piece of the shipping channel now known as Leidse Rijn was excavated from Oog in Al to the Harbour near the Catherine Gate (Catarijnenpoort). In 1670 three parallel canals were dug to provide room for expansion of the city. This however never materialised, as by then Amsterdam had taken over the leading position in the northern Netherlands. As a result the Bleyersgraft, Herengraft, Blomgraft, Mariensgraft and Geertegraft were known as Moesgrachten (named after the moestuinen or vegetable gardens that were made here).

Utrecht around 1675 marked the end point of the reworking of the floodplain. The new canal known as Leidse Rijn (Leyden Rhine) comprises of three consecutive section (1), (2) and (6). Another canal is the Biltse Vaart (5). The fortifications are improved, first on the westside (3) and later on the eastside (4). Improvements in the drainage situation are executed east of the city in the shape of the Zilveren Schaats (7) and the cut at the country estate of Amelisweerd (8). Due to the diminished amount of water flowing through the dammed Rhine the river has started to wind within its old stream bed.