New locks in the Albert canal in Flanders, Belgium

Because of climate change, Belgium is experiencing more and longer periods of drought. In the future this is projected to be aggravated. According to the climate projections developed within the Cordex.be project, (2015–2017), changes in precipitation and evapotranspiration in the period 2000–2100 indicate in summer months deepening of negative water balance, causing an increasing risk of the occurrence of droughts and their higher severity. While winter precipitation is expected to increase slightly, summer precipitation will significantly decrease. The expected decrease in precipitation simulated by the models for August varies between -10% for the emission scenario RCP2.6 up to approximately -40% for the emission scenario RCP8.5 by the year 2100 in comparison with the year 2000. In the eastern part of Flanders one of Belgium’s biggest canals is situated: the Albert canal. This canal connects the industrial zones from the (French-speaking) Walloon part of Belgium with Antwerp, Belgium’s largest harbour. Ships can continue at both ends of the canal, to the Netherlands (e.g., Rhine, Rotterdam) and to France (Meuse). Because of the building of the canal also some important industrial areas were developed along it, making it an economically extremely important waterway for Belgium, with a total traffic of 40 million tons per year. The canal gets its water from the river Maas (Meuse), a river only fed by rain. The Maas is also feeding other canals, with the Juliana canal to the Netherlands being the most important. So agreements had to be established with the Netherlands to address situations of extreme weather events, including low water discharges resulted from droughts. In some (rare) cases, the discharge of the river Meuse is not enough for feeding all canals in Flanders and the Netherlands, and for maintaining a minimum discharge in the Meuse itself. During these periods, the water level of the Albert canal can drop, so that the allowed draft for ships has to be reduced, making inland navigation less attractive as transport mode. Up to now, these problems were addressed by a number of measures, such as lift-locking of professional shipping with less water and limiting water withdrawals for agricultural and nature management purposes, but these measures implied accepting associated economic and ecological damages.

The main objective of the measures described in this case study was to avoid economic losses due to reduced traffic possibilities on the canal (due to very low water discharge from the Meuse river), which are expected to be aggravated in the future because of climate change. Protecting the Meuse river ecosystem and biodiversity was another secondary objective.

Big Archimedes screws were built at the locks in the canal in Ham, the first of six lock systems. In case of drought these enormous screw pumps, the biggest in Europe, are pumping up water lost by the passing from the ship through the lock. In case of an excess of water, mainly in winter, the screws are used as a bypass to get rid of the excessive amount of water. In that case, the pumps work as an electricity generator, with hydropower as renewable energy reducing GHG emissions. The net effect on GHG emissions over time depends on the balance between low and high water levels, but since until now low water levels have been occurring only rarely, the net effect is generally positive. The canal is also a possible waterway for migrating fish. Therefore the screws are designed to allow fish migration, protecting biodiversity. The installation in Ham (2012) consists of four enormous screw pumps with 4.3 m diameter and weighing 85 tons. The screws can pump up to 5 m 3 per second. One lock operation moves 48,000 m 3 of water. The four screws need 50 minutes on full power to pump the water back. In 2013, three similar screws were installed in Olen. Having proved their functionality and effectiveness, installation of screw pumps on the Albert canal’s locks continued in 2018, when three Archimedes’ screws were built in Hasselt. The colossal screws – 22 metre long, 4.30 metre diameter, weighing 100 tons - can pump 5 m 3 water per second to the top of the lock, and with enough water they can produce green electricity for 1,500 households. The pumping installations in combination with hydropower plants are being built also on the other locks of the Albert canal of Genk, Diepenbeek and Wijnegem. These are expected to be put in operation after 2021.

The cost of the installation of the screws is about 7M€ for each lock system. The benefits include the navigability of the canal under changed climatic conditions, the reliability of the canal for shipping and the generation of electricity. Green electricity (hydropower) for an equivalent of 1,000 families can be produced by each set of screw pumps. In the past years it was observed that the installation functions as power generator for about 10 months per year and pump up water for about one month. Another month usually stands in a situation of just sufficient run-off for shipping but insufficient flow for power generation. On an annual basis much more energy is generated than used. The precise annually generated power depends on the amount and distribution of precipitation over the year, the shipping intensity and the withdrawals from other water users. There are also biodiversity benefits. Because of the relatively high water quality, rich fish stocks occur in the canal. Advanced technologies used for the pumping installations and power generation minimize the impacts of the installations on the fish stocks.

Important success factors included the acknowledgement of ecological values to be maintained and the attention to the development of a collaborative process in which all stakeholders were seriously engaged. As to the former, two ecological factors played a key role: the structural possibility to protect some ecosystem services in the Meuse valley by limiting extraction of Meuse water and maintain a sufficiently high run-off level, and the consideration of the fish stocks in the Albert canal. As to the latter, the process highlighted the importance of allowing sufficient time and resources for stakeholders to cooperate, share knowledge, understand each other and get to know and respect each other’s culture. Imposing solutions or taking insufficient time would have limited success. One of the main factors of success to collaborate was the awareness of the inadequacy of current solutions and projected worsening of the situation in terms of frequency and length of low water levels.