Subject

Conversion of the solid weir into a flap weir in Lewin Brzeski in km 13.80 of the Eastern Neisse River together with accompanying facilities.

Improvement of the flood protection status of Lewin Brzeski on the Eastern Neisse River in connection with the reconstruction of the solid weir into a movable weir and flood clearing of the river bed.

THE PURPOSE OF THE INVESTMENT

The aim of the planned investment was to adapt the Lewin Brzeski hydrogeological node to the safe passage of flood waters with the flow rate of up to 800 m3/s-1 and to protect the adjacent areas and the town of Lewin Brzeski against floods.

Scope of the development

In particular, the scope of the study concerned:

• demolition of the damaged oblique solid weir and its replacement by a three-span flap weir with a low sill;
• unblocking of the Eastern Neisse riverbed from km 16+000 (bottom threshold) to km 11+600 (railway bridge), desludging and shaping of the two-part riverbed together with the execution of shore insurance;
• clearing of the road bridge light on the route from Lewin Brzeski to Niemodlin;
• construction of a right-bank side overflow at km 15+250 of the Eastern Neisse in order to safely take over a part of large waters;
• clearance of the flood relief route, which will enable the safe passage of large waters taken over by the overflow outside the urban area;
• unblocking the inflow and outflow zones of the road bridge over the flood relief together with protection under the bridge;
• construction of new and modernization of existing flood protection embankments together with service roads and access roads for maintenance and repair purposes;
• shaping of floodplains in order to increase the capacity of the river valley;
• reconstruction and construction of new embankments and road culverts.

Under the contract, a multi-variant concept was developed, a project information sheet, an environmental impact report with a decision on the environmental conditions for the implementation of the project, water law reports on the execution of water structures and on specific water use with a decision on the water law permit, a construction project with a decision on the building permit, executive documentation, cost, specifications for the execution and acceptance of works and author's supervision. The investment was completed in 2014.

Basic parameters of the objects

1) Dependable flow Qm = 600 m3·s-1.

2) Control flow Qk=800 m3·s-1.

3) Three-span weir:

• IV class of importance of hydrotechnical structures;
  
• Weir light (three spans) 3x17.00 m - 51.00 m;
• normal water damming level - 146.10 m above sea level (Kr);
• normal drop - 2.80 m.

4) Technological bridge over weir:

• total width 5.20 m;
• three bays with a span of 17,00 m, one with a span of 2,90 m.

5) Flood embankments classified to the II class of importance of hydrotechnical structures.