In 2004, by the decision of Minister of Environment, “Hydroprojekt” reinstated works on FEASIBILITY STUDY of Nieszawa-Ciechocinek barrage   Why Nieszawa?   The idea of the construction of the barrage between Nieszawa and Ciechocinek has been a subject of many discussions and publications. The current condition of the Vistula River valley between Plock and Torun is a result of realization of the Wloclawek barrage, being the first element of so called Lower Vistula Cascade, planned since the 50s. It was constructed  between the years 1962-1970 Wloclawek barrage. Cascade, planned contemporarily as a modern waterway, was to have navigation and energetic significance, allowing for simultaneous usage of hydroenergetic potential of the river. Making decision  to construct Wloclawek barrage, it was assumed that the next barrages of the cascade will be developed as well. The next one was to be the barrage in Ciechocinek, but preparation works for construction have been stopped due to the shortage of financial means for investment continuation.   Wloclawek barrage   Wloclawek barrage has been left as the only one on the Lower Vistula River, functioning in conditions, which were not taken into consideration in the assumptions and technical solutions. As a result, intensive erosion of the Vistula River bed, covering  almost 30 km river reach and causing  lowering of the water level right downstream  the barrage by 2.5 m up to over 3 m in relation to the primary conditions. In effect, the water had  maintained by barrage structures increased for about 0.25, and safety factors of concrete barrage structures – weir and hydropower plant – approached  the minimal permissible values. Filtration through the subsoil  and earth dam’s body, intensified  by increase of water head and lowering of the water level downstream reservoir, causes systematic loosening of the soil and threatens with failure. In such a case, the humongous flood wave caused by sudden emptying of the Wloclawek reservoir of capacity approximately 400 mln cu m, as well as moving of the significant part of 40 mln cu m of settlements accumulated in the reservoir would cause disastrous effects for the Vistula River valley, its inhabitants, environment and economy. Results of this catastrophe would influence not only the Vistula River valley downstream Wloclawek, including particularly the river reach nearest the barrage, devastated already by erosion. Additionally damages or hazards would endanger ecosystems in the area of the reservoir, created during 30 years of its existence and several industrial plants (including petrochemical works in Plock) would suddenly remain without water.   Currently, the following engineering structures endangered with progressive erosion are excluded from exploitation: grain elevator port - deprived of water access summer port deprived of  water access winter port deprived of  water access water intake for “Drumet” without water municipal boulevard – limited functions road bridge – potholes at the piers threatening with the lost of stability Zglowiaczka river mouth – endangered rivermounth reach development water intake for Nitrogen Works “Anwil” – low water level limits efficiency of the intake two pipelines of the ethylene from Petrochemical Works in Plock to Nitrogen Works “Anwil” – washed away riverbed  caused uncovering of the pipelines and creation of the dents two pipelines of the gas products PERN – as above two pipelines Jamal-Europe – washed away river bottom over the pipeline   Low water level   Assumptions for designing   Construction of the barrage in Nieszawa-Ciechocinek region is a basic solution for returning the right conditions of the Wloclawek barrage usage and, at the same time, fulfilling the significant role in the reconstruction of the river valley, destroyed by many years of erosion processes.   The basic assumptions and guidelines for barrage designing has been determined in part I of the Feasibility Study, elaborated by “Hydroprojekt” in 2002 and approved by Technical Board with participation of representatives of Ministry of Environment and Regional Water Management Authorities in Warsaw.   Nieszawa-Ciechocinek barrage is to be, in accordance with obligatory assumptions, a raising water structure working without downstream support, i.e. conveying water to the riverbed, protected with river training structures. It imposes particular requirements regarding structure itself and operation rules for the objects letting water in the barrage as well as preparation of the downstream and a proper training of the riverbed.   At the determination of the assumptions for designing for the new barrage ,conclusions coming out from elaborations covering research and analyses related to the exploitation of the Wloclawek barrage have been used.   The following conclusions have been drawn: technical solutions for the structures of the barrage should allow their proper and safe operation in assumed lifetime, without necessity of construction of the next barrage. there suppose to be implemented solutions minimizing the influence of the barrage on the intensity of the downstream erosion process, particularly:   - absorption of the flood waves and ice floes by the weir without damages in the downstream of the barrage; - application of the weir with the low sill (0.5÷1.0 m) enabling free flow of sediments - flow river power station, - appropriate depth of the downstream with taking into consideration low water levels in the riverbed. Choice of the barrage sitting.   Primary idea of the sitting of the barrage in Ciechocinek region was created along with design of Wloclawek barrage. Project solutions of the Wloclawek barrage, especially regarding the the downstream station and river benches development in Wloclawek are adjusted to the river water head , determined in the contemporary conception of the Ciechocinek barrage.   In the next studies, variants of the barrage sitting on the river reach between Nieszawa and Ciechocinek have been analyzed in the following crossections: km 699.00, km 703.75, km 707.90 (dam and weir) and km 711.00 (water power station and navigation lock).   Comparison  of the considered variants of the sitting led to the selection of two of them:         Nieszawa                          in km 703.75 of the river course         Ciechocinek                      in km 707.90 of the river course.   The sitting of the barrage in Nieszawa region restores normal exploitation of the Wloclawek barrage, enables effective co-operation of the water power plants in Wloclawek and Nieszawa and ensures appropriate conditions for the construction of the new barrage.   Sitting of the barrage in Ciechocinek region performs the same functions as determined for Nieszawa barrage and additionally creates better conditions for energy generation. Although much bigger financial outlays for preparation of the reservoir’s bottom, larger costs of exploitation of the object and very difficult conditions of the hydraulic structures, related to the very unfortunate hydro geological conditions should be taken into consideration.   The significant is also an issue of the potential hazards resulting from sitting of the barrage right above flood embankments of the Ciechocinek Health Resort.   Both sitting options are currently analyzed in details in terms of the technical and economical aspects along with  determination of the impact on the environment.   Conceptual design of the barrages in chosen variants of location   In every analyzed sitting option, investment consists of the following structures:         weir         water power station         navigation lock         fishpasses (technical and ecological).   On the crest of the raising water structures, the road bridge enabling creation of the new road connection of the national significance has been designed.   Existing conditions result in significant differentiation of the spatial layout of the barrages Ciechocinek and Nieszawa, as well as geometrical dimensions of particular objects, in spite of retaining identical hydrotechnical parameters (such as normal water level, span of the weir, working dimensions of the navigation lock) and technological parameters of the water power station. Determination of the final layout of the barrages and technical solutions for hydraulic structures requires simulation on the hydraulic spatial model.   Location of Nieszawa Barrage   General characteristics of designed barrages   Nieszawa barrage Ciechocinek barrage Nominal water level NWL = 46.00 m asl NWL = 46.00 m asl Water head H = 7.20 m H = 8.05 m Discharge capacity at NWL Q = 6 500 cu m/s Q = 7 100 cu m/s Water head at max designed water level Q0,5%=9,780 cu m/s Hmax=47.55 m asl Hmax=47.04 m asl Water head at max probable water level Q0,1% = 11 580 cu m/s Hmax=48.31 m asl Hmax=47.87 m asl Concrete structure crest elevation 50.51 m asl 50.07 m asl Earth structures crest elevation 49.00 m asl 50.60 m asl Weir - 16 span, 20 m each - sill of Jambor type, 1.0 m high, - steel radial gate with flap, 8.5 m high. Navigation lock - working dimensions of the navigation lock 120 x 12 m, depth on the sills 4.0 m - navigation lock dimensions are adopted to the waterway of  Va class. Fishpass - fishpass of the chamber-cascade type in the separating  pier between water power station and weir - “site” fishpass, on the left river bank. Water power plant - nominal use of water – 1200 cu m/s (6x200 cu m/s) - river power plant   for Nieszawa sitting - rated power – 46.5 MW, - annual average power generation - ~280.0 GWh/a   for Ciechocinek sitting - rated power –60 MW, - annual average power generation – 350.0 GWh/a Nieszawa-Ciechocinek barrage shall enable hydropower plant Wloclawek to reinstate the pumped storage work with annual average power generation of – 700~GWh/a.   Shape and other characteristics of the reservoir.   Shutting the river by the Nieszawa or Ciechocinek barrage will cause creation of the reservoir in the Vistula River valley within the limits of the riverbed. Only the areas  situated below nominal water head shall be flooded and inundation area will be limited by coffer dams and leveling works in the reservoir’s bed.   The side embankments will be created through raising and strengthening of the existing flood protection levees as well as through the construction of the new embankments for protection of the areas situated below nominal water head and adjacent to the barrage.   Total length of the side embankments, on both sides of the reservoir, equals:         Nieszawa reservoir         modernization of the existing embankments – 7.7 km         newly constructed side dams and frontal dam – 9.3 km         Ciechocinek reservoir         modernization of the existing embankments  7.7 km         newly constructed side dams and frontal dam – 17.3 km The surface of the area protected against flooding:         Nieszawa reservoir – 600 ha         Ciechocinek reservoir – 1200 ha Depending on the land use on the protected areas water regime regulation with pumping stations, drainage and ditches etc. has been presumed.   As an ecological compensation for flooded areas it has been proposed to form numerous. clusters (isles) of total surface of 200 ha. They  will be arranged in accordance with guidelines elaborated by natural scientists.   Basic parameters of the designed reservoirs Nieszawa and Ciechocinek in reference to Wloclawek reservoir Type of parameter Ciechocinek reservoir km 707.9 Nieszawa reservoir km 703.75 Wloclawek reservoir km 674.85 reservoir’s length (km) 33.05 28.9 57.0 reservoir’s capacity at the nominal head (mln cu m) 131.02 95.0 370.0 reservoir’s surface 3100 2404 7500 nominal head (m a.s.l.) 46.00 46.00 57.30 min. head (m a.s.l.) 45.50 45.50 56.50 max head for QM (m a.s.l.) 46.95 47.55 58.50 average depths at the nominal head 3.40÷7.50 3.40÷7.30 5.5÷15.0 The advantages of the barrage construction: for water management - flood protection of the areas surrounding reservoir and adjacent to the downstream of the barrage - decrease of the height of the pumping of water in the surface water intakes (municipal and industrial), - elimination of the costs of the reconstruction and maintenance of the riverbed on the length of reservoir. for inland transportation - road bridge  on the barrage shortening the road connections between  the villages on the both sides of the river and will also serve as an emergency bypass for the  designed highway A-1, and  for the existing  national road no. 10 Warszawa-Szczecin. social effects - economical recovery of the boroughs localized in the region of the barrage development, caused by creation of the new jobs at the construction, increase of demand for services, and after finalization of the construction, by possibility of transformation of the appurtenant structures  for recreational purposes. for agriculture - reservoir’s impact will include water regime regulation, improving problem of water deficiency during vegetation period on the areas endangered by turning into steppe, - balancing deficiency of precipitations (100÷150 mm annually) by feeding reservoir with ground waters will enable improvement in the structure and quantity of the arable crops. for environmental protection - reinstatement of the natural functions performed by clusters on the Vistula River, - increase and stabilization of the groundwater level  within the area of reservoir’s impact, -  energy generation from natural resources. for tourism and recreation - water reservoir will enable development of various forms of tourism and water sports, - the value of the areas adjacent to the reservoir will increase as a result of transformation of their function from rural to recreational. for fishery - conditions for development of fish breeding and increase of the fishery will be created. for inland navigation - construction of the reservoir will allow for lengthening of the Plock-Wloclawek waterway, belonging to the 4th European class. - reinstatement of the passenger navigation on the Plock-Nieszawa river reach should be expected. for energy generation - direct advantages , enabling  full repayment of the barrage construction costs and gaining profits out of its exploitation: - energy production - services included in Operation Manual for Maintenance and Exploitation of Sub transmission Grid. - improvement of the economical effects of water power plant in Wloclawek after transfer to peak operation pumping station - indirect  advantages achieved  due to the substitution of the work of thermal power plants; - technological effect (the difference in the demand for energy between thermal power plants and water power plants), - localization effect (decrease of the energy loss during transmission to the local users), - ecological advantages such as: decrease in the amount of burnt coal, decrease in emission of toxic gases, decrease  of a number of coal combustion products (coal dust, furnace waste, slags). - activity aiming at fulfilling obligations resulting from signing by Poland Geneva Convention and accepting European Parliament Directive regarding limitation of the emission of the pollutants from significant combustion sources. Conclusions construction of the barrage in Nieszawa-Ciechocinek region enables comprehensive solution of the problems resulting from many years of exploitation of the Wloclawek barrage in conditions inconsistent with assumptions for its designing, development of the barrage on the Vistula River is an undertaking expensive, which may be financed from the national budget only partially. Possibility of repayment of the investment costs and achieving profits from exploitation of the barrage is available from selling power generated by water power plant. compensation operation of the Nieszawa-Ciechocinek reservoir enables proper use of Water power plant in Wloclawek and increase of its economical efficiency.