The subject of the contract is: - construction of underground retention tanks with a dry chamber of pumps / gate valves, technological equipment and ventilation installation, - construction of a technological chamber with a rainwater pretreatment system along with a ventilation installation, air dryer installation and heating, - execution of energy supply and control of tanks and technological chamber, - construction of gravity rainwater drainage, - construction of discharge pipes, - construction of ducts water supply, - construction of gravitational sanitary sewage system, - reconstruction of the existing utilities of the area colliding with the planned investment, - liquidation of the existing utilities of the area colliding with the planned investment, - reconstruction of road surfaces after works related to the implementation of the contract, - construction of exits, access roads, sidewalks, bicycle paths, - restoration of green areas, - execution and implementation of executive projects of temporary traffic organization, - felling of trees and shrubs, replacement plantings, - preparation of as-built documentation.

Part 1 of the contract covers the execution of construction works specified in the tasks: 1) C1_K6_8.3 - "Construction of retention reservoir No. 3 with network connections, object installations and a rainwater and meltwater treatment system for watering greenery in the area of Markwarta Street in Bydgoszcz" 2) C2_K8K9_4.4_4.11 - "Expansion of the rainwater sewage system in the area of Szymanowski Street in Bydgoszcz" 3) C2_K8K9_4.5 - "Expansion of the rainwater sewage system in the area of Skłodowska Street in Bydgoszcz Bydgoszcz" including m.in.: - construction of retention reservoirs with a capacity from V=300m3 to V=855m3 A detailed description of the subject of the contract is presented in the Description of the Subject of the Order (hereinafter OPZ), constituting Part III of the SWZ.

Part 2 of the contract covers the execution of construction works specified in the tasks: 1) C3_K13K13.1_4.1 - "Construction of retention reservoir No. 1 with network connections and object installations in the area of Szubińska Street in Bydgoszcz" 2) C3_K13K13.1_4.21_2.33_4.36 - "Construction of a section of rainwater sewage system - reconstruction No. 1, connection collector No. 1, increasing capacity No. 1 in Gołębia and Piękna Streets in Bydgoszcz" 3) C3_K14_5.1 - "Expansion of the rainwater sewage system in the area of ul. Fallow land – Retention reservoir no. 1 with connections" including m.in.: - construction of rainwater channels in the diameter range from DN200 to DN1000 with a total length of 465m,  construction of retention reservoirs with a capacity from V=204 m3 to V=1086 m3. A detailed description of the subject of the contract is presented in the OPZ.