New challenges in water supply require new solutions
In parallel with the construction of the desalination plant, Region Gotland has seen a need to contribute to the development of complementary systems for the water supply of the future. For this purpose, Region Gotland, together with IVL Swedish Environmental Institute, has begun the construction of a so-called test bed for sustainable water supply. This testbed will focus on the development of future technologies for energy-efficient and sustainable water production.
Goal of the test bed
Since Storsudret is among the places in Sweden that are most sensitive to prolonged drought, Storsudret was chosen as the place for the test bed. The idea is that the systems that are developed will meet the most difficult challenges in water supply. The goal of the test bed is to make Storsudret self-sufficient in water but also to put Sweden and Gotland on the international map for cost-effective and sustainable systems that solve problems related to water shortages, regardless of whether it is on Gotland or elsewhere in Sweden or the world. The challenges are the same, saving water from the rainy season to longer dry periods.
The test bed is built in close collaboration with KTH, Uppsala University, the Swedish Geological Survey and the companies Monson Energy and ENWA. Forum Östersjön is an important interest association that safeguards the interests of the residents of Storsudret and adds valuable local knowledge to the test bed about how the water balance works locally. The construction of Testbädd Storsudret is financed by Vinnova and the participating organizations. The project also has funding from the EU through the NextGen project.
Water is not a problem but the storage
The lack of water during parts of the year is due to Storsudret's thin soil layers that have little ability to store water. This and the large proportion of land that is drained means that precipitation is transported quickly from agricultural land to the sea. During a normal year, it rains about 70 million cubic meters on Storsudret's surface. Of this volume, 20 million cubic meters of water remain after evaporation. By succeeding in utilizing about 1% of the precipitation that falls on Storsudret during a year, there is enough water to cope with the water supply.
The problem is that most of the precipitation comes when it is not needed, that is, during the winter months. If this is to be sufficient, the water must therefore be collected, stored and reused. That's how this is going to go to what we need to learn. If we succeed, these technologies can be used worldwide and save on both costs and energy, while Gotland and Sweden can gain a prominent position in this vital area.
Small-scale, local systems
The heart of the test bed is many sensors that measure precipitation, flows in ditches and groundwater levels in real time and online. In addition to providing the researchers with data, the sensors' data will be used for active control of the water balance at Storsudret. This is achieved by using the ditches that today remove water from land and into the sea to instead, through active regulation, function as a collector of water for storage for the summer. During the dry summer period, purification techniques for reusing wastewater are developed by purifying this to drinking water quality. In order to be able to store larger volumes of water, membrane technology is being developed to be able to purify water from shallow lakes in a robust way. To avoid long pipelines, technology is being developed to find groundwater reservoirs close to designated new construction areas.
Common to the systems is that these must ensure that water levels and groundwater levels are kept controlled so that no forest, agricultural land or other land use is adversely affected. This is achieved through the system that controls and controls the water balance at Storsudret.
PU:REST – A beer brewed on reclaimed wastewater
The technology for purifying wastewater into drinking water exists today and IVL has shown this when they brewed a beer, PU: REST together with Nya Carneigebryggeriet and Carlsberg Sweden in the spring of 2018 and which clearly demonstrated that wastewater recycling is entirely possible and completely safe. PU:REST also demonstrated how the development of new systems for water supply is fully possible if we together push the boundaries and dare to think in new directions. In this way, we can manage the world's water supply in a sustainable way, both from an energy and climate perspective and from a cost perspective. At the same time, Gotland and Sweden place on the map for the water supply of the future.
Local connection and engagement
To give and get ideas for how the water supply should be managed in the best way is the local engagement. This is mainly done though close collaboration with the local NGO Forum Östersjön. Together with Forum Östersjön Testbed Storsudret arrange meetings, “Coffee-dialogs”, open for all inhabitants at Storsudret but also meetings in smaller groups with landowners and other stakeholders.
Measurements of flows and groundwater levels
During the summer of 2018, measuring instruments were installed in various catchment areas at Storsudret for real-time measurements of precipitation, flows in ditches and groundwater levels in three areas:
A weather station was also installed to obtain locally specific weather data. The data that is continuously collected is the basis for calculations of water balance in the different areas and shows how much water is available during the year.
The image above shows the infrastructure for real-time water metering that includes surface water flows (SY), groundwater levels (SGV) and the weather station VS1.
Measurement program for wells
To get even more information about the water supply at Storsudret, the project has also invited residents to share information. This has been done by interested well owners registering their well for the project. By continuously measuring the water level in a number of different wells distributed over the project area, more information about groundwater levels is included for the project. A well, especially a well located in the soil layer, gives a good picture of the groundwater level in the specific area at the time of measurement.
The heart of the test bed, which consists of real-time sensors for precipitation, surface water flows and surface and groundwater levels.
Map of the mapped wells on Storsudret, most of which have been excavated
The surface level in digged private wells
The figure shows how the groundwater levels have varied since the measurements began in August 2019 in four of the wells included in the measurement program. Where the wells are located can be seen in the map above.
As a simplified explanation for the curves, groundwater levels usually rise during late autumn and then fall during summer. During November and December, more rain came than usual on Storsudret, which caused the groundwater to rise.
The recovery during autumn, winter and early spring is important for the groundwater to last the rest of the year.
If you want your well to be included in the measurement program, contact Anton Rydstedt.
Real-time measurements of groundwater levels and flows in the ditches at Storsudret
Realtidsmätningar av grundvattennivåer och flöden i diken på Storsudret
Facts about the project
Vinnova & EU program Horizon 2020 via the project NextGen
Vinnova project Testbädd Storsudret:
Region Gotland, ENWA, Monsson Energy, SGU, KTH, Uppsala University, Forum Baltic Sea
Koordinator KWR in Netherlands, KWB, AVB and ESCI in Germany, FHNW i, UCRAN, UNEXE, UBATH in UK, STRANE in France, CTM in Spain, NTUA, ICCE in Greece, IPSTAR in Netherlands, WssTP in Belgium, Region Gotland in Sweden, AVA and CTU in Switzerland.
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