Joanna Kocięcka, Daniel Liberacki, Piotr Stachowski, Mariusz Korytowski, Jerzy Mirosław Kupiec
Poznań University of Life Sciences, Poland
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Drainage systems are responsible for maintaining adequate soil moisture levels and alleviating negative consequences of excess water coming from the spring thaw as well as torrential rains. In the face of the climate change and pervasive extreme weather conditions, the importance of these ameliorative measures will be increasing. It is imperative to ensure appropriate functioning of these drainage systems. To be effective they need to be adequately operated and maintained, with maintenance measures performed appropriately and with required frequency. Basic ditch conservation procedures include mowing to remove vegetation overgrowth and cleanout to remove sediment. A significant problem in Poland results from an insufficient number of renovation and conservation operations performed on drainage systems, their gradual deterioration and depreciation. As a result, it is crucial to assess the need for renovation and modernisation of drainage ditches. It needs to be remembered that these operations interfere with the environment and may cause some unfavourable ecological changes. In view of the above, the authors of this publication conducted a thorough evaluation of both the required renovation of the investigated drainage ditch system and its current ecological status. The study area comprised the Strumień Junikowski catchment with the main outlet, i.e. Strumień Junikowski, its tributaries (the Skórzynka, Ławica, Plewianka, Ceglanka) as the main collection ditches and field ditches. During the field inspection the existing drainage structures were inventoried, with their technical condition assessed according to Kaca and Interewicz (1991). In this paper the characteristics of habitats found in the drainage area of the watercourse are presented along with the bioindicator analysis performed using the Macrophyte River Assessment Method. Based on the MIR index the ecological status of the stream was assessed and classified in accordance with the Water Framework Directive. The results demonstrate a significant variation of the ecological state of Strumień Junikowski over its entire course. The condition of the drainage structures in the drainage area varies. In the main watercourse of Strumień Junikowski the inspected culverts are in a good condition in contrast to the ones located on the tributaries. Vegetation overgrowth and sediment deposition in the ditches are major problems of the drainage area. This is caused by a lack of effective and systematic maintenance and renovation of the watercourses. The Strumień Junikowski drainage area is further being developed, which is associated with a rapid and increased discharge of rainwater and snowmelt. Thus it is necessary to maintain drainage ditches to ensure their optimal condition, which is essential to decrease the risk of flooding in the urban areas adjacent to the watercourse.
renovation, modernisation, maintenance, drainage ditches, drainage measures, ecological status, Macrophyte River Assessment Method