Hydraulic Analysis of Temporary Flood Hazard to Support the Planning of the Construction Phases of Hydropower Plants

Gašper Rak, and Franci Steinman

Fluid Mechanics with Laboratory, Faculty for Civil and Geodetic Engineering, University in Ljubljana, Slovenia

Abstract: In the planning stage of the interventions in water space and riparian areas hydraulic model research of runoff regime is an established tool in the search of the final solution, which in addition to providing the functionality provides the preservation or mitigation of flood and erosion hazard. To support construction, stepwise planning of temporary structures and measures, etc., is crucial as well. The importance of analyzing the runoff regime in a particular intermediate phase of the construction is mainly reflected in sitting of an extensive and complex intervention, the construction of which takes place a long time, with changing environmental and hydraulic conditions. One should be aware that during the period of construction the temporary state in the area (particularly in an intermediate phase of construction) could have a significantly more adverse effect on the runoff regime (and consequently on adjacent activities and space users) than a final design state. Temporary flood hazard hydraulic analysis in the planning of construction phases is presented on the case of sitting interventions according to the national spatial plan of HPP Brežice, to identify potential intermediate increase of hazard and risk, higher than that predicted for the HPP under full operation. Consequently, the planned construction process was adapted and optimized, which helped to reduce risks as well as costs.

Key words: hydropower plant, construction phase, flood control, numerical model, physical model