the lake. The lake is still visited by the fishermen and has a reputation of a lover's lane. One of the classical works of Serbian filmmaking, The Marathon Family by Slobodan Šijan, was partially filmed on the lake in 1981. Public transportation line, bus No 408, connects Trešnja with Belgrade. In order to make water less polluted, Belgrade administration and Forestry Institute jointly organized a project of naturally cleaning the lake water using floating islands, through the process of phytoremediation. The process was tested for the purposes of cleaning the highly polluted Topčiderka river, but was applied for the first time at Trešnja. First group of floating islands was placed on the lake surface in May 2019. They were removed in September 2019 and replaced with the new group of 50 plant islands in 2020. Constant testing of the water showed that the project was successful as the water in the vicinity of the island was cleaner, moving from the very bad, fourth category regarding pathogen bacteria, into the first, excellent category. The islands are made of edible canna, common reed, yellow iris, Siberian iris, common water-plantain and purple loosestrife. No chemicals are applied and the mineral wool is used as the growth substrate. City planned to protect the forest in Trešnja in the 1960s. A decree was adopted in 1970 but never took effect, being suppressed by the new law on forests. Koviona, southernmost extension of Trešnja. It developed in the late 1970s. As it grew, it spread along the streets into the areas of the neighboring settlements Mala Ivanča, Ralja and Parcani. The hamlet had a population of 1,500 in 2022, and is notorious for the waterworks problems, which caused denizens to occasionally protest in public and to block local roads. The plan was made in 2009 to conduct water to the area, including the construction of the "Trešnja" complex of water reservoirs, but nothing has been done by June 2022 when it was announced that reservoirs will be built across the municipal border, in the Sopot municipality. The contractor was selected in December 2021, but the original project was declared "technically impracticable". New project, which includes three reservoirs, Koviona I, II and III, was drafted, but due to the disputes between the Sopot municipality and Belgrade administration, no works began by February 2023, and likely won't any time soon. At this time, it was announced also that