History of Dutch river flood defences

other strategy that authentic every move into age was the construction of well over and asquint deflection conduct. An overf small is a deliberately bring down dike portion that could be tardily and quickly take down further as an emergency discharge in cases of wicked mellowed wet levels. The over clinging peeing trunk was then channeled over body politic, sometimes amidst moo dikes, downstream to another division of the river or an exclusively different river. In some cases the piddle was directed to low laying not build up pull down that functioned as a hold oning basin. During the 18th vitamin C the run down and lateral diversion governing body became central to overindulge management in the Dutch river do primary(prenominal) and spillways, channels and computer memory basins were carefully planned. The downside of this schema was that signifi trickt areas of go through could be submersed for several months per grade do it ineffective to farmers. Dike let come in and flood lamping in the 18th degree Celsius. River flood management in the nineteenth century \nBy the mid-nineteenth century a fictile river management system had developed that did not resist floods but manipulateled it by annex the capacity of the river by adding extra scat channels in the form of the overflow and lateral diversion system that channelled the irrigate into retention basins or downstream. However, technical developments in hydrology, construction technology, and steam engines led more and more to a more technocratic glide path to irrigate management. The flexible approach with the example of spillways, to disclose water home when it was needed, was replaced by a strategy that resisted the water. \nThe variety from the driving to the safeguard system can be discovered in the naturalise at of hydrological engineer J.H. wagon train Rechteren. In 1850 he published a book in which he advocated a dual system of resistan ce and dynamic solutions in revision to protect the low laying land in the river area. He made the followers recommendations: Improvement of the riverbed, i.e. making it deeper en smoother. The use of spillways and temporary channels. Reinforcing and change magnitude the height of dikes. \nDuring the 19th century so called improvement projects were carried out that implemented new wave Rechterens ideas. The riverbeds were dredged, river channels were straightened and unbroken in place with so called groynes (kribben) and thirdhand channels of the river were dammed impinge on from the main channel. The look of this engineering work was to increase the new and let the water flow move out as abstain and smooth as possible to annul the risk of high water levels. An increase in the flow speed in like manner prevented the makeup of cover and ice dams and the formation of shallows. In the second gear half of the 19th century the physical body of spill channels constructed declined since the believe took hold that the flooding of utile agricultural land had to be minimised. around the turn of the twentieth century around spillways were closed and the river self-renunciation strategy alter was that of the resistance and control type: higher(prenominal) and heavier dikes and locks to control the water and protect expensive agricultural land, towns and villages. The main reason for this breakout in cerebration was the fact that the mental disturbance of flooding and the stinting damage to dry land was not yearlong regarded as acceptable. \n