Aa River (Meuse)

The Aa at Middelrode

The Aa is a small river in the east of the province of North Brabant in the Netherlands. It has a length of about 90 km. The now straightened river rises near Meijels in the province of Limburg and flows in the center Duke bush together with the channel Zuid- Willemsvaart and the river Dommel. These form the Dieze that flow north into the bush Duke Maas. With the straightening of Aa was begun in 1922.

Formation

The Aa is formed during the last ice age. During the Pleistocene, about two million years ago the Meuse was a tributary of the Rhine, and flowed at the height of Cologne in the Rhine. After the ice had retreated, the terminal moraine formed near Utrecht and the Veluwe, the rivers were looking for a new run. The Ardennes eliminated from the Meuse Rhine, making them much further north until it flowed in Utrecht and the Veluwe their direction westward modified by the delta of the Scheldt, Rhine and mass to form. Tectonic shifts in the Groote Peel was in the East North Brabant with the high moors with buttons and Griendsveen. The fluvial sediments of the Campine region, and the high moors of the Groote Peel poured into the old valley of the Meuse. In this way arose from west to east the rivers Reusel, Beerze, Dommel and the Aa. Each of these rivers had and has its own tributaries.

Course

The source of Aa in North Brabant is situated near Meijel the north of the Dutch province of Limburg. Initially westward flowing, their direction changed to flow between Asten and Someren finally to the north. In Lierop the Small Aa flows into the arteries. The river flows through the middle of the Nieuwe Aa Helmond, Helmond north of where the creek flows to Bakelse Aa. After the Aa Beek en Donk has left behind, it flows schnurstraks north direction. Shortly before the Erp of the river bends widely from west to subsequently flow through Erp. Then, Veghel divided by the Aa in two. The river continues to flow to the north and passes through the community Heeswijk Dinther - close. After the river Berlicum has happened, he reached the Hintham district of the city 's-Hertogenbosch. In De Muntel district Aa, the channel Zuid- Willemsvaart and the Dommel flow together, and form the Dieze. Current flows at the height of Crèvecoeur in the Meuse. Arms of the original untamed Aa embraced in earlier times partially Hertogenbosch, but already in 1544 the Aa was firmer passed through Hertogenbosch, probably to improve the sewage system function. By applying the canal Zuid- Willemsvaart 1822-1826 the old connection was interrupted at the main power of Dieze, so that the river now forms the northeastern moat and feeds this water. If the water level of the river Meuse does not allow drainage of the Dieze, the water is discharged through a drain. Result, the flow direction of the moat is reversed and the Aa flows through the bed of the Dommel in the north.

Economic use

Since time immemorial served the river to get out of the higher sandy soils on which most of the population had taken place, remove excess water. With increase in population, the lower-lying wet meadows and nearer the water Sandy soils were colonized. This happened especially in Aarle- Rixtel, Beek en Donk, and Heeswijk - Dinther Keldonk, which meant that residents had to fight in these communities regularly with flooding. Although the Aa was formerly deeper and wider, had been too low their capacity to absorb excess water always. Especially in the winter months, the loss of livestock and fruit as a result of high water were high. The bed of Aa was in poor condition and the millers it is situated on the river water mills let the water flow as they see fit, creating large pools produced in different places, which in turn were responsible for flooding. The many water mills on the Aa and the indiscriminate use of water through the Müller gave rise to many strife. This led to the extent that an appeal was made in the first half of the 16th century even to the Emperor Charles V. to mediate directly in this conflict. This could deepen the river in 1545 and represented the extent of the water determined that each Müller was allowed to infiltrate. These measures were followed until the outbreak of the Eighty Years' War in 1568 put an end to this. After the affected communities knew no more advice, they went on to buy from them rejected water mills to grind them. This plan was put into action almost everywhere.

1573 allowed the city Helmond to make the right downriver ship bahr to a range of Aa Philip II (Spain ), in his capacity as Duke of Brabant. Due to the scarcity of material fire in s-Hertogenbosch plans were made to improve the Aa in its role as a transportation route on. Between 1624 and 1628, therefore, the river at various points locks was deepened and already existing restored. In December 1627, the first barge of Helmond went to Hertogenbosch and back. The journey took three days. As a result of the Siege of 's-Hertogenbosch by Frederick Henry of Orange in 1629, and the subsequent fall of the city, these plans were not followed up later. 1739 and 1798 was considered by the original plans but yet to be implemented. Due to disagreement between the various communities and the question how each community had to contribute to the costs, these plans were never realized. Indeed, it was clear that the expected return of proportion would be the costs. Until about 1840, the Aa for small boats and rafts of Erp to -Hertogenbosch was navigable. At the height of Keldonk the river was even then very broad terms (about 7 meters). Several locks made ​​sure to soften the height difference.

River regulation

Begun with the construction of the canal Zuid- Willemsvaart, 1823 and 1826 completed, the Aa their function was deprived as a waterway. However, the problems due to regular flooding of pasture and arable land in the largely agrarian environment of the Aa remained. Only with the establishment of the water composite Lower Aa ( Waterschap Beneden de Aa) in 1864, which merged in 1924 in the larger Wasserverbund De Aa ( Waterschap De Aa), it was decided that the problems to solve structurally in which the Aa would be channeled. The work was started at the beginning of the 30s of the 20th century. 1200 workers made ​​sure that all branches of the Aa disappeared, so that the flow lost its characteristic meandering structure. Several dams were created to prevent a too rapid flow of water. Initially, the work was carried out with spades and wheelbarrows. It was only in the 60s of the 20th century came heavy equipment to use and finally got the Aa its present face. The straightening of the Aa changed sustained the surrounding landscape and made sure that the species composition of plants and animals decreased. The wet meadows, which disappeared surrounded by reed ponds and ponds with their stock of fish, birds and plant species, to make room for farmland.

The Aa today

Since 2004, the flow field of Aa is part of the water composite Aa and Maas ( Waterschap Aa en Maas ). End of the eighties of the 20th century slowly ecological awareness began to develop. This had the consequence that is currently trying to repair the damage to the landscape, to a certain extent caused. Old river loops like the ones at Castle Heeswijk be carefully maintained. The water creates composite nature-friendly banks and in some places the river has its original meandering course receive back, such as north of Helmond. However, not all flow loops can be restored, but they are simultaneously at locations of the river, at which never have found flow loops, created new ones.

Development projects

Dynamic stream valley (Dynamic Beekdal )

The aim of this project is the water between Heeswijk Dinther - and -Hertogenbosch to grant more space, creating a natural momentum to be built, so that downstream problems are to be prevented by flooding. The completion of this project is planned for the year 2010.

Master Plan Aa Veghel

This project aims to restore the course of the arteries within the community Veghel. It affects the river from the A50 motorway in the north to the beginning of the district Erp, a distance of about 8 km. With the first phase of this project began in June 2007.