Ecobeach has quite a number of different potential users. A natural increase of the beach volume can be interesting for economic reasons. Furthermore, it causes little CO2-emission during the operational phase. Ecobeach can also widen and stabilize the beach. The different potential users are presented below.
Ecobeach is responsible for sand accretion of the dunes due to increase of aeolian transport of sand to the dunefoot. The increased sand volumes at the dunes provide an additional buffer to withstand extreme erosion due to generated waves during extreme storm events.
Ecobeach also coarsens the beach leading to increase of stability. As a result, beach erosion will reduce during storm events. Furthermore, the multi-annual fluctuation of beach width caused by recurring beach nourishments followed by beach erosion will reduce significantly.
Increase of beach and dune robustness will be beneficial for water boards because less maintenance activities have to be carried out in order to maintain the coastline. The reduced amount of beach nourishments will decrease the recurring fluctuations of the coastline significantly. This leads to a situation that beach restaurants will remain at the same location without being located at the dunefoot one year and at the lowest part of the high water line the next year.
Ecobeach generates a larger width at the higher part of the beach. A larger width of the beach increases its recreational function especially during average high water. In this situation, the beach of coastal communities remains accessible for recreational purposes. The inconvenience of periodical beach nourishments for recreational beach purposes can be prevented by installing the Ecobeach drainage system.
A stable and spacious beach will reduce the quantity of necessary sand transport carried out by beach restaurant owners in order to sufficiently generate a wider beach in front of their beach restaurants. Besides this advantage, it is not needed to excavate the sudden increase of sand volumes at the dunefoot after each beach nourishment in order to create more space. Consequently, Ecobeach will save the associated costs for the so-called "sand on wheels" of which municipalities generally contribute as well.
Large fluctuations of the beach width sometimes cause the high water line to come near the beach restaurants leading to inconveniences to recreational hikers and emergency services. These fluctuations can be limited due to stabilization qualities of Ecobeach. The wider and higher elevated beach surface results in an increase of available drier beach area in front of the beach restaurants during an operational high tide event.
When the higher parts of the beach becomes wider, more recreational beach visitors can find an empty spot near the beach restaurants. Ecobeach can maintain a sufficiently large dry beach area for the restaurant clients even during high tide events.
The enhanced robustness of the beach caused by Ecobeach limits the number of "sand on wheels" which is usually necessary after the winter season to create more space for recreational purposes. Ecobeach also reduces strong fluctuations of the quantity of the sand volumes and makes temporary discomforts caused by beach nourishments obsolete. Beach restaurants do not have to be relocated regularly (less dependent of growing and receding beach areas and dunefoot due to weak variations of the sand volume quantities).
Recreational beach visitors
Ecobeach creates a wider and more elevated beach surface to provide more space for recreational beach visitors during the summer (especially when high tide events occur). More typical beach activities can be promoted. Nonetheless, a rapid response team, for emergency purposes, is able to reach the area of interest when necessary even during high water events.
Since the Ecobeach drainage tubes are installed 25 cm below the beach surface, recreational beach visitors will not be disturbed by this system. Despite of that, local erosion due to storm events may cause exposure of some of the tubes occasionally. However, when exposure of tubes occurs, it would be fast and easy to reinstall these tubes to deeper positions at the beach.
The responsible authorities will reduce the expenses for maintaining the coastline by installing the Ecobeach system.The relatively expensive beach nourishments can be replaced by applying foreshore replenishments combined with the Ecobeach drainage system. Reduction of beach nourishment frequency is another substantial advantage regarding this innovation by BAM.
Beach nourishments usually have a short lifetime in general, because natural equilibrium will eventually be recovered due to wave attacks and current effects. After foreshore replenishment is applied, waves will transport the sand to the beach. These foreshore replenishments combined with the Ecobeach system will keep the sand at the beach for a longer period.
The aeolian transport of the sand particles to the dunes will increase the dune development. Consequently dune sand will increase leading to an additional buffer against large storms. These storms may cause erosion to the buffer without endangering the coastline. The coarsening of the beach provides more stability. Hence an average storm that mainly erodes sand at the areas between high and low water line, will have less impact to the existing sand volumes.
The difference in costs (unit price per cubic meter sand) between beach nourishment and foreshore replenishment is mainly determined by transport costs and demand and supply in the dredging market. According to STOWA (Dutch foundation on watermanagement researches), it is determined that the price of a beach nourishment equals € 5.00 / m3 and the costs of a foreshore nourishment equals € 2.75 / m3 including admission fee and 21% VAT.
Dredging companies are usually contracted to maintain coastlines. By applying Ecobeach for this reason, dredging companies are able to realise the works for a lower price. The lifetime of nourishments can be extended when combining with the Ecobeach system provided that replenishments are done at the foreshore. Consequently, the construction will save costs and will be environmental friendlier and will maintain the desirable beach width.
Some countries are lacking of sand in order to carry out beach nourishments or the sand extraction locations are depleted. In those cases, it is essential to extend the lifetime of beach nourishments as long as possible by applying passive beach drainages.
The scientific research regarding the Ecobeach pilot at Egmond aan Zee was supervised by BAM. It was a versatile multidisciplinary research involving several universities, companies and research institutes. A number of interesting results were achieved that contribute to the understanding of the general coastal system. Measurement results of the ground water behaviour and the sedimentstructure are analysed and presented in different graduation theses. A morphological analysis by BAM can be found in these theses.
Input from several universities, mainly TU Delft and VU Amsterdam, has been provided for this research. Scientific disciplines, such as coastal engineering, (geo) hydrology, coastal ecology, geotechnical engineering and coastal morphology have worked together during the scientific period. Three scientific workshops have been organized during the pilot: at the start, halfway and at the end of the pilot project. All the disciplines described above have participated during these workshops they brainstormed about the research fields and reflected on the results.
BAM intends to continue incorporating the scientific research during future Ecobeach projects in order to improve and enhance the comprehension of the complex coastal system.