Abstract:
According to the data offerred by the National Agency for Land
Improvement, in Suceava county there is a surface of 44904 ha with drying
up workings, of which 27455 ha with drainage workings. The network of
drying up canals is 1875 km long and the undergroung drainage network is
made of absorbant collector drains and has a total length of 11909 km.
After 27 years of exploiting the network of drying up canals, a
modifications of the geometrical and structural parameters have occurred
(depth, width at the bottom, the embankment coefficient and the light of the
canal) through bank errosion and clogging of the canal bottom.
The degree of bank errosion and canal clogging in the drying up and
drainage systems is influenced by water velocity, the stability of the
embankments and the weed growth, as well as the use category of the
surfaces disserved by the canals.
In the case of dried up and drained surfaces used as pastures, the
bank errosion and canal clogging is more obvious and the medium occurring
ratio is almost double comparing to the one of the canals which disserve
surfaces used as arable land and hayfield. On the surfaces used as pastures,
weed growth is more reduced, and on some areas there is no grass at all, a
result of uncontrolled grazing and canal crossing by animals, during periods
with excessive himidity. As to surfaces used as arable land, the embankments
of the canals are covered with grass, which, on one side reduces bank
errosion, and on the other, if left unmown, after some time, it favors the
appearance of hydrophile vegetation and shrubs, hindering the water flow
and clogging acceleration.
The clogging of the canals blocks the evacuation holes of the drens,
especially the collector drens which are deeper.
Considering the relatively large surface which a collector-drain
disserves, the obturation of the evacuation hole must not be neglected and
urgent remediation measures must be taken, as it may require the whole
collector-drain to be put out of function and lead again to an excessive
humidity on the entire surface disserved.
