The Nida River flows trough the southern part of Poland. The basin of this river is localized mainly in Swietokrzyskie province. It is a longest river in this province (151.2 km) flowing in it's upper part trough the southern part of the Swietokrzyskie Mountains. In most part Nida is a not regulated lowland river, characterized by the slope of about 0.65 promiles. The Nida River valley between cross-sections Stara Wies and Pinczow had been strongly transtormed. Between villages Stara Wies and Motkowice, the typical river training had been done. The river also was partially trainned on the distance between Motkowice and Pińczów as well as in the short distance below Pinczow. The Nida River embankments are localized in the middle part so a big part of the river valley cannot be used as a small retenition. These narrowly distributed fortiffications are in a weak condition, what causes that spring flood waves which often reach the top of the embankments can easily destroy the embankments and flush onto the valley some of their parts together with the sandy substratum from below. The water flowing trough the destroyed part of the embankment transports the high volume of sand from the riverbed which, ...
In the 70-ties and 80-ties the river training was done in the Nida River. The river itself near Pińczów was shortened and the new channel was created. After the old channel near MOSiR recreational center was widened and deepened, the pińczowski reservoir was build in 1973 and then modernized in 80-ties. On east-southern in the place where in the past was a bridge in Nida River there is a district road running. At present the outflow culvert is localized there from which the water passes to the trapezoidal channel and then to the old channel. Finally the part of the water goes on the wetlands and the rest, below Pińczów, back to the Nida River. The length of the outflow channel is in total about 1.3 km, and the slope varies from 0.16 to 0.37 promiles. The water flows to the reservoir from the river by the side intake and stays there in average of 8 days. The projected retention period is about 5-6 days, and the time estimated on basis of current measurements of morphological, biological and water quality parameters should not exceed 2-3 days. Presently it is not possible because the outflow culvert was done without according to ...
1-dimensional models, e.g. HEC-RAS, MIKE 11 are used to calculate water surface elevation concerning probable discharges for flood hazard areas designa-tion. Hydro-informatic software programs HEC-RAS and MIKE 11 are used for modeling of water discharge in the river bed and in the river valley, with engineer-ing objects of complicated structure (bridges, culverts, weirs etc.). The following stages of modeling may be distinguished: schematisation of water network, geodetic measurements of the river bed and engineering buildings, identification of roughness coefficients, hydrological calculations of discharges in selected profiles of the modelled watercourse considering the boundary conditions, numeric calcu-lations with calibration and verification of the model as well as visualisation of the calculations' results. The paper presents the results of modeling of a sector of The Lubcza River in the Wislok basin having length equal 8,7 km (uncontrolled basin), in which 17 bridges and 12 weirs are located. The elevations of the water surface for di-scharges of the defined probability of exceedances and the Digital Model of the Water Surface (DMWS) are the basis for the analyses and comparison of the obta-ined results. Flood hazard areas occur on the intersection of the Digital Terrain Model (DTM) and DMWS. The knowledge of water ...
Paper concerns the investigations of riverbed sediments in the meandering sector of the Border Odra, In the frame of meander I. As a result of fluvial processes the Odra riverbed is exposed to deformations, leading to often changes of the river itinerary. In the historical time, many meander breaks were registered, the last in 1967 (Meander IV) and in 1997 (Meander I). In the old river bed the discharge is gradually decreasing and the substantial part of the discharge is flowinging through the new channel. It leads to gradual silting of the old river part. The intensive formation of bars and of islands is observed. In the upper part of the old meander, mainly the bed load is deposed, and in the middle and lower part – the suspended load. The superficial part of the layer (cover) is exposed to the formation of pavement. The size of the pavement cover is equal 8,4–9,8 cm, and the granulometry of the lower layer (20–40 cm) equal to d50 = 2,3–2,9 cm. The islands formed by fine sediments were covered in 3-4 years by intensive vegetation (trees and bushes). This process causes an important decreasing of flow velocity in the old channel. The ...
