During the winter, not many water restoration measures are carried out in Sweden, instead, new upcoming measures are planned and designed (as we have written in previous posts). The measures planned within Improve Aquatic LIFE generally require some type of preliminary investigation before implementation. This is important to avoid negative impacts and to ensure that the measure achieve their intended effect.
A level and flow meter in Lake Elsabo. Photo: Mattias Larsson.
Summer drought is a natural phenomenon, but in many parts of the country it is becoming increasingly common as a result of a warmer climate. To address these challenges, it may in some cases be necessary to adapt both watercourses and lakes to better withstand dry periods. One solution is to modify lake outlets so that they save water over a longer period of time during lower flows, a so-called low-flow adaptation. Within Improve aquatic LIFE, a low-flow-adapted outlet will be constructed in Lake Elsabo (River Nissan’s catchment area), which has recurring problems with low water levels during summer. Prior to implementation, it is important to gain a clear understanding of water levels in the lake and flows in Sågån. The measure is primarily intended to benefit the protected Freshwater pearl mussel found downstream of Lake Elsabo (and which has previously also in Sågån). Therefore, the project partner Swedish Anglers Association, in collaboration with the project partner Jönköping County Administrative Board and Jönköping Fisheries Biology AB, has installed water level and flow gauges. Data is collected continuously and can be followed via www.vattennivå.nu. The data collected is necessary to best adapt and design the new outlet. The aim is to start and complete the measure in 2027.
Meeting the challenges may in some cases require measures to adapt both rivers and lakes to better withstand drier periods
Elevation measurements of Jeppeshoka, River Mieån. Photo: Anna Hansson.
Another type of survey that is often carried out when removing migration barriers is elevation measurements of the river and the dam structure to determine the extent of the impounded area. Such a survey was carried out at Jeppeshoka sawmill, River Mieån. The dam has already been partially lowered for about 10 years but still constitutes a migration barrier for fish. The measure aims to remove the two spillways and the dam gates but preserve the other cultural environment for the future. The measure can hopefully be implemented in the summer of 2027 and will benefit not only fish migration but also reproduction of the endangered Freshwater pearl mussel that lives in River Mieån.
Preserving other cultural heritage for the future