The aim of river and valley restoration is re-establishment of natural or close to natural state in which the river channel and valley were before regulation works. River and valley were losing their natural state due to various factors. Mostly, it was connected with the radical changes as the result of the regulation works, i.e. river bed straightening , river gradient increase, standardization of size and shape of river cross section , liquidation of banks and channel bed irregularities, ecotones destruction, cutting off links between old river-bed and main river channel, reduktion in overbank flooding and floodplain storage. Increasing of water pollution in the past it was also chemical factor which changed natural state of rivers. Restoration is usually long-lived process which consists of different technical measures and induced by them ecological changes of water body and surroundings areas accomplished by nature. The full re-establishment of natural state is not possible in practice. By the time the restoration works begin the hydrological, hydraulic and environmental conditions should be recognized. The restoration works may be placed in the river bed, bank zone, along river valley and in tributaries or in the catchment area. The process of restoration encounters many and varied ...
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, ...
