A fascine mattress(Dutch: Zinkstuk, literally sink piece), is a large woven mat made of brushwood, typically willow twigs and shoots, used to protect riverbeds and other underwater surfaces from scour and erosion. They are similar in construction to a fascine, but are primarily used for hydraulic engineering works, typically to strengthen the banks of rivers and streams, as well as coastal structures like revetments and groynes.
Modern fascine mattresses utilise a layer of geotextile in order to fulfill the competing requirements of water permeability balanced with the need to be impervious to sand. Prior to the advent of synthetic geotextiles in the 1960s, a layer formed from reeds was incorporated to make the fascine mattress sand-tight. [1] [2] [3]
Fascine mattresses have been used worldwide, [4] but are particularly common in The Netherlands, where significant expertise in their preparation and construction is available, and where the materials required for their construction are harvested in specially created plantations. [5]
Zinkstuk have been used in The Netherlands for river and coastal engineering works since at least the 16th century, and were discussed extensively by Andries Vierlingh in his Tractaet van Dijckagie (English: Treatise on dike building), the manuscript of which was not published until 1920, and is now housed in the Nationaal Archief. [6]
The materials for fascine mattresses in The Netherlands were traditionally harvested in osier beds along rivers such as The Merwede, particularly around the Biesbosch, where the materials were grown and coppiced in order to produce the mattresses. The towns of Werkendam and Sliedrecht are notable as centres of zinkstuk fabrication and construction expertise. [7] [8]
In the 16th century, dike workers in The Netherlands were often impoverished, taking on jobs under a day-rate contract. Dike building works were usually tendered in the month of March and often had to be completed by August, and fascine mattresses were a common feature of the work. [8]
By the end of the 17th century, floating fascine mattresses had been introduced for closure works in the Netherlands, with the mattresses being assembled and then towed to the required location, where they were ballasted by rocks and then immersed by sinking. This technique was used as scour protection at the bed level, and the ability to stack layers of fascines on top of each other in the required location up to the level of low tide with this method made gradual closures possible. [9]
In the mid to late 19th century, fascine mattresses were used across the Netherlands, including in works at Schellingwoude and the Sloedam, along with sections of embankments at the Hollands Diep and shore protection works in Westkapelle. [10] Sections of the Rhine between Lobith and Pannerden were strengthened by fascine mattresses from 1851. [11] Fascine mattresses were also used extensively in the construction of sections of the Amsterdam Ship Canal and the Port of Rotterdam. [12] [13] By the middle of the 1800s, engineering knowledge around fascine mattress installation had begun to be included in Dutch engineering textbooks. [14] [15] [16]
By 1910, the town of Werkendam was home to 160 fascine mattress workers (rijswerkers), some of whom worked abroad. Their wages at the time ranged from 12 to 18 guilders per week. As Dutch dredging and hydraulic engineering contractors began to undertake works internationally, the workers earned up to 50 guilders per week overseas. Much of their income was spent on basic sustenance, with workers often living on the worksite in a hut or cabin. An average of eight months per year was spent at fascine mattress work, with the remaining four months (usually from November to March) spent on tasks such as coppicing and harvesting. [7] [8]
The main component of a traditional fascine mattress is willow twigs, which are formed into a wattle. Willow timber has several properties that are important throughout the process of creating and sinking a fascine mattress, being flexible, robust, and buoyant. The manufacturing process of a traditional fascine mattress begins by winding rope around the willow in both directions using a machine, resulting in a lengthy roll known as a wattle. [1] [2]
Historically, a considerable number of skilled workers, known in the Netherlands as rijswerkers, were required to create wattles at a proprietary stand. Nowadays, with the use of machinery, this process is more efficient and allows for adjustments to the thickness and length of the wattle as required. [1] [2] [17] [18]
The mattress is assembled on a patch of ground adjacent to the water, and once the wattle is complete, the mat is towed to the desired location and sunk to the bed using dumped stones. The bottom layer of a traditional fascine mattress is a lattice structure composed of wattle, spaced around one metre apart. On top of this base are arranged two crisscrossing layers of willow twigs, referred to as the first and second brush layers. [1]
To ensure the fascine mattress is sand-tight, a layer of reed is inserted between these brush layers. Occasionally, for added stability, a third brush layer may be placed above the second. Following this, an upper lattice of wattle is installed to secure the entire structure. [19]
The cohesion of the mattress is then reinforced by tightly binding the upper and lower lattices together using ropes. In The Netherlands, it is common to add tuinen, a type of fencing, to the top of the fascine mattress in order to prevent the stones dumped onto it from rolling off during underwater immersion. [5] [17]
Timber stakes are used to mark out a working grid, indicating the precise positions for the layout of the wattle. Then, the brushwood is layered between the wattles, followed by the addition of the second brush layer, before the top layer is positioned. By this stage, the fascine mattress is around half a metre thick. Finally, the bindings are tightened to create a coherent, unified structure ready for installation. [17]
The construction of the Delta Works, prompted by the effects of the North Sea flood of 1953, was of such a vast scale that tremendous quantities of brushwood would have been required to utilise traditional fascine mattresses across all of the Delta Works projects. As a result, the Deltadienst department of Rijkswaterstaat decided to undertake research and experiments at the Waterloopkundig Laboratorium, to investigate the possibility of improving the traditional mattress and reducing the quantity of brushwood required. [20]
This work coincided with the advent of synthetic geotextiles in the late 1950s and early 1960s, and traditional fascine mattresses began to reduce in popularity, with use being made of woven polypropylene fabrics in place of the reed underlayer. [21] [22] [17] [23] Traditional fascine mattresses are however still used, with their application often limited to locations where synthetic materials and plastics are discouraged or prohibited for environmental reasons. [19] [21] [24] [25] [26]
For the Delta Works, 'block mat' fascine mattresses consisting of a fabric with concrete blocks attached were rolled up and immersed by unrolling the mat with a special ship, the Cardium, during the construction of the Oosterscheldekering. These mattresses were reinforced with steel cables to mitigate the effects of tension. [27] [28] [29]
Modern fascine mattresses are made using a woven polypropylene fabric which is water-permeable, sand-tight and contains pre-woven loops. The loops allow the fabric to be attached to a wattle grid using a rope, without the need to create holes. [24] [19]
These modern mattresses are much thinner than traditional mattresses, with a longer design life. The function of the wattle grid is to provide sufficient buoyancy and rigidity to the fabric during the sinking process. The absence of a wattle grid precludes the underlayer fabric from being uniformly flat across the riverbed or underwater surface onto which it is placed. The grid also prevents broken stone from rolling off, particularly when used on revetments or sloping surfaces. [24] [30]
Fascine mattresses are immersed by dumping stone or rock onto the surface, causing it to sink to the bottom. In tidal waters, this must occur at a time when there are no (or very low) tidal currents, usually at slack water. Once the fascine mattress is in place, the underlying bed is protected from erosion by the flowing water and deformation of the riverbed or bank is negated. [24]
The dumped stones ensure that the mattress remains in place and provides protection against wave action on banks. The design life of a fascine mattress can be as much as 100 years. [24] In the past, a fascine mattress was immersed using skilled labour placing stones on it by hand, such as during the construction of the Afsluitdijk. [31] It is important that the stones are applied evenly, and that everyone is clear of the fascine mattress at the time of sinking. [19] [17] Modern mattresses are placed using civil engineering plant such as crane barges, long reach excavators and, in deeper water, side stone-dumping vessels. [24] [32]
Placement of a mattress in conditions where there is a flowing current is nearly impossible with this method, [24] however placement using a pair of pontoons and a side-stone dumping vessel is possible. In the latter situation, the mattress is connected to a pair of sinking beams (hollow tubes), which are filled with water at the appropriate time to sink the mattress. After immersion, these sinking beams are disconnected from the mattress, filled with air, and recovered. [24]
Fascine mattresses have been used in projects across the world, and their use in The Netherlands has been extensive, including projects such as the Afsluitdijk and Delta Works projects such as the Zandkreekdam, Volkerakdam, Brouwersdam, and Grevelingendam. The technique was also used in Zeeland for dike reinforcements in the Eastern Scheldt and in the construction and extension of the piers of IJmuiden and the widening of the North Sea Canal. [33] [34] [35] [36] [37]
Extensive use of fascine mattresses was made during the emergency recovery works following the Inundation of Walcheren, with the rijswerker Gerrit Visser of Van Oord decorated by the authorities in Zeeland for supervising the immersion of 36 fascine mattresses over a total area of 52,700 square metres during the works. [8] Visser is portrayed as the character Klaas Otterkop in A. den Doolaard's non-fiction novel Het verjaagde water. [38]
The ideas of Andries Vierlingh, as set out in his Tractaet van Dijckagie, were used in the 16th century by Cornelius Vermuyden for his drainage works in England. [39] [40] [41] Around 1750, the Dutch engineer Cornelis Janszoon Meijer introduced fascine mattresses for bed protection works in Italy. [42] [43]
At the request of the Japanese government in the 1870s, a number of Dutch hydraulic engineers were invited to improve hydraulic engineering works in Japan. [44] These engineers included Cornelis Johannes van Doorn, who was in charge of renovation work on the Tone, Edo and Yodo Rivers, along with works on the Asaka Irrigation Canal in Fukushima Prefecture and the Nobiru Port in Sendai Bay. [45]
Van Doorn introduced fascine mattresses and rijswerkers during the period 1872 – 1880, [46] and the art and science of making fascine mattresses subsequently became known in Japan as the Westerwiel method, named for one of the Dutch rijswerkers, [47] and is now known in Japan as the "Japanese traditional method". [48]
In 1849, the British engineer Charles Blacker Vignoles visited Dutch contractors Aart Schram and Leendert Martinus Prins in Sliedrecht, and arranged for them to travel to Kyiv and install fascine mattresses as scour protection to the piers of the Nicholas Chain Bridge, which had suffered extensive damage during construction. [8] [49] [50]
Other examples of the use of fascine mattresses outside the Netherlands in the 19th century include riverbank improvement works by James Buchanan Eads on the southern Mississippi, using fascines made from Poplar trees and shoots grown on the banks above Baton Rouge, and protection works using fascine mattresses made from mangroves on the coastline of British Guiana. [51]
Fascine mattresses continue to be used internationally, [52] [53] [54] including for bed protection works in Bangladesh, Vietnam, India, and Laos, particularly in the framework of development aid projects. [55] [56] One benefit of the method is that whilst these systems are labour intensive, they do not require significant capital expenditure, which is therefore an advantage in developing countries. [57] [9]
Geosynthetics are synthetic products used to stabilize terrain. They are generally polymeric products used to solve civil engineering problems. This includes eight main product categories: geotextiles, geogrids, geonets, geomembranes, geosynthetic clay liners, geofoam, geocells and geocomposites. The polymeric nature of the products makes them suitable for use in the ground where high levels of durability are required. They can also be used in exposed applications. Geosynthetics are available in a wide range of forms and materials. These products have a wide range of applications and are currently used in many civil, geotechnical, transportation, geoenvironmental, hydraulic, and private development applications including roads, airfields, railroads, embankments, retaining structures, reservoirs, canals, dams, erosion control, sediment control, landfill liners, landfill covers, mining, aquaculture and agriculture.
Geotextiles are versatile permeable fabrics that, when used in conjunction with soil, can effectively perform multiple functions, including separation, filtration, reinforcement, protection, and drainage. Typically crafted from polypropylene or polyester, geotextile fabrics are available in two primary forms: woven, which resembles traditional mail bag sacking, and nonwoven, which resembles felt.
Geosynthetic clay liners (GCLs) are factory manufactured hydraulic barriers consisting of a layer of bentonite or other very low-permeability material supported by geotextiles and/or geomembranes, mechanically held together by needling, stitching, or chemical adhesives. Due to environmental laws, any seepage from landfills must be collected and properly disposed of, otherwise contamination of the surrounding ground water could cause major environmental and/or ecological problems. The lower the hydraulic conductivity the more effective the GCL will be at retaining seepage inside of the landfill. Bentonite composed predominantly (>70%) of montmorillonite or other expansive clays, are preferred and most commonly used in GCLs. A general GCL construction would consist of two layers of geosynthetics stitched together enclosing a layer of natural or processed sodium bentonite. Typically, woven and/or non-woven textile geosynthetics are used, however polyethylene or geomembrane layers or geogrid geotextiles materials have also been incorporated into the design or in place of a textile layer to increase strength. GCLs are produced by several large companies in North America, Europe, and Asia. The United States Environmental Protection Agency currently regulates landfill construction and design in the US through several legislations.
Mechanically stabilized earth is soil constructed with artificial reinforcing. It can be used for retaining walls, bridge abutments, seawalls, and dikes. Although the basic principles of MSE have been used throughout history, MSE was developed in its current form in the 1960s. The reinforcing elements used can vary but include steel and geosynthetics.
Cellular confinement systems (CCS)—also known as geocells—are widely used in construction for erosion control, soil stabilization on flat ground and steep slopes, channel protection, and structural reinforcement for load support and earth retention. Typical cellular confinement systems are geosynthetics made with ultrasonically welded high-density polyethylene (HDPE) strips or novel polymeric alloy (NPA)—and expanded on-site to form a honeycomb-like structure—and filled with sand, soil, rock, gravel or concrete.
Johannes Aleidis (Johan) Ringers was a Dutch hydraulic engineer and politician. He served as the director-general of Rijkswaterstaat and later as the director of Dutch East Indies Railways. During World War II, Ringers was appointed as the government commissioner for reconstruction, but was later interned by German forces.
Johannis de Rijke was a Dutch civil engineer and a foreign advisor to the Japanese government in Meiji period Japan. He made significant contributions in the enhancement of Japan's river systems and the development of its port facilities, which were vital in the industrialisation and infrastructure advancement of the nation during the Meiji era.
Jean-Pierre Giroud is a French geotechnical engineer and a pioneer of geosynthetics since 1970. In 1977, he coined the words "geotextile" and "geomembrane", thus initiating the "geo-terminology". He is also a past president of the International Geosynthetics Society, member of the US National Academies, and Chevalier de la Légion d'Honneur.
The International Geosynthetics Society (IGS) is an engineering professional society focused on the field of geosynthetics, which are polymeric materials used in geotechnical engineering. The IGS describes itself as "a learned society dedicated to the scientific and engineering development of geotextiles, geomembranes, related products, and associated technologies." It was founded in Paris in 1983 as the International Geotextile Society and is a member of the Federation of International Geo-Engineering Societies, along with the International Society of Soil Mechanics and Geotechnical Engineering (ISSMGE), International Society for Rock Mechanics and Rock Engineering (ISRM), and International Association for Engineering Geology and the Environment (IAEG).
Het verjaagde water is a 1947 Dutch non-fiction novel written by A. den Doolaard, which gives an account of the recovery works to repair dike breaches after the October 1944 Inundation of Walcheren as part of operations by The Allies of World War II during Operation Infatuate. Researchers from Delft University of Technology have found high levels of historical accuracy in den Doolaard's descriptions of the events that took place, the methods used to close the dikes and the key people involved. Den Doolaard assigned pseudonyms to most of the main characters and organisations. The name A. den Doolaard is also a pseudonym, the author’s real name being Cornelis Johannes George Spoelstra Jr.
The Volkerakdam or Volkerakwerken is the name given to a group of hydraulic engineering structures between Goeree-Overflakkee and North Brabant in the Netherlands. The works are not a single dam, but are composed of three distinct structures: a dam between Goeree-Overflakkee and Hellegatsplein, a series of locks from Hellegatsplein to North Brabant, and a bridge from Hellegatsplein to Hoekse Waard. The works cross three separate bodies of water: the Haringvliet, Hollands Diep and Volkerak. The works together comprise the fifth project of the Delta Works.
The Grevelingendam is a dam located in the Grevelingen sea inlet between Schouwen-Duiveland and Goeree-Overflakkee in The Netherlands. The Grevelingendam was the fourth structure constructed as part of the Delta Works.
Pieter Jacobus (P.J.) Wemelsfelder was a Dutch hydraulic engineer who made significant contributions to the field of hydrometry in the Netherlands, and in hydraulic engineering internationally. In addition to his involvement in the design and planning of the Delta Works, he published widely and is notable for the first use of probability theory in the design of flood levels.
Frank Spaargaren was a Dutch hydraulic engineer who was one of the main designers of the Oosterscheldekering and served as a director of the Waterloopkundig Laboratorium in Delft.
Pieter Philippus Jansen was a Dutch civil engineer and hydraulic engineer who made significant contributions to hydraulic engineering in The Netherlands. He spent the majority of his career with Rijkswaterstaat, working on several major projects including the first phase of the Delta Works and leading the reclamation and repair efforts following the inundation of Walcheren.
Jan Fokke Agema was a Dutch hydraulic engineer and professor at Delft University of Technology. He is notable for his design of the harbour entrance at Hoek van Holland and involvement in the construction of the Oosterscheldekering. The prof. dr.ir. J.F. Agemaprijs is named for him, and has been awarded every five years since 2000.
Emmericus Carel Willem Adriaan "Wim" Geuze was a Dutch civil engineer who contributed to the development of soil mechanics, and the founding of the geotechnical engineering journal, Géotechnique. He was head of research at the Laboratorium voor Grondmechanica in Delft, and professor of soil mechanics at Delft University of Technology and the Rensselaer Polytechnic Institute.
Albert Sybrandus Keverling Buisman was a Dutch civil engineer and Professor of Applied Mechanics, who was instrumental in establishing the Laboratorium voor Grondmechanica in Delft. He made notable contributions to the development of soil mechanics in the Netherlands.
In coastal and environmental engineering, the closure of tidal inlets entails the deliberate prevention of the entry of seawater into inland areas through the use of fill material and the construction of barriers. The aim of such closures is usually to safeguard inland regions from flooding, thereby protecting ecological integrity and reducing potential harm to human settlements and agricultural areas.
Krystian Walenty Pilarczyk is a hydraulic engineer whose contributions to civil and hydraulic engineering include the development and improvement of the Izbash formula, along with the Pilarczyk formula for the stability of block revetments. He is the author and editor of a number of academic papers and textbooks on coastal, river, and hydraulic engineering subjects.