9 Deforestation and Frequency of Floods in Romania
297
In the Cri¸ suri river basin, floods are formed in all seasons of the year, depending on
the moisture intake brought by the air masses. The floods of 1970 had as a triggering
factor a heavy rainfall regime. The whole period from January 1 to May 10 was rich in
rainfall, with double quantities of water in relation to the normal multiannual values,
which caused the infiltration of at most 20–25% of the amount of water lost, the rest
entering the drainage process. The value of damage to the Cri¸ suri catchment area
amounted to more than 128 million euro at present (390 million lei in 1970). Between
May 7 and 9, 1989, in the river basins of the Barc˘ au, Cri¸ sul Repede and Cris , ul Negru
rivers, large amounts of precipitations fell, which overlapped over a period when
the soil was soaked with water, which caused most of the rainfall to contribute to
surface leakage. The floods formed between December 1995 and January 1996 had
the following causes: warming and rapid melting of the snow layer, especially in
mountainous and hilly areas, the disappearance of ice on rivers, liquid precipitations
marked quantitatively in the conditions of a frozen soil, unable to allow infiltration,
and water leakage on the slopes to the riverbeds.
Among the most famous floods in the Some¸ s—Tisa hydrographic area, there are
mentioned 1970, 1974, 1975, 1978, 1979, 1980, 1981, 1989, 1993, 1995, 1998, 2000,
2001, 2006 and 2008.
In the 1970s, floods were due to long-lasting heavy rainfall, which exceeded the
critical thresholds, causing the overflow of most rivers. In 1974, during the June-July
period, the floods occurred due to precipitations that far exceeded the average annual
precipitation in the watersheds Tur, Some¸ s, Crasna and Vi¸ seu.
In 1980, the floods were due to a repeated fall on a saturated soil, which exceeded
the critical thresholds, exceeding the defense rates on most of the watercourses in
this hydrographic area. On the Almas , , Crasna, Agrij, S˘ alaj, Budac, Zal˘ au, Olpret, Iza
and Batarci rivers, have overcome 2–3 times the hazard. On the Tur river, the hazard
was exceeded 4 times. The most important floods occurred in July when at the Sighet
Weather Station were registered 178.6 l/m
2 , at Ocna S , ugatag 158.6 l/m
2 , 146.5 l/m
2 at
the Negre¸ sti Oa¸ s pluviometric station, 137.5 l/m
2 at Vama and 116.9 l/m
2 at Turulung.
On the lower courses, due to the small slope, the floods lasted up to 7 days.
In 1981, the floods were due to precipitation, melting of snow and leakage on the
slopes, causing on most of the watercourses in the basin, rises in levels that have
exceeded the defenses. In 1995 and 2001, the floods occurred in December due to
precipitation in the form of rain and rapid melting of snow, favoring the emergence
of flood waves on S , omesul Mare and tributaries, Tisa and tributaries, L˘ apus , , Cavnic,
Tur and tributaries. In 1998, the floods from June were due to particularly abundant
precipitation that caused rich leaks on the slopes and in 2006, on the Ili¸ sua river, a
tributary of the Somesul Mare river, was a rapid flood, in June, as well. The total
duration of the flood was 34 h and the maximum flow about 212 m
3 /s (Cristes , tii
Ciceului hydrometric station). This has caused 13 human lives and a lot of material
damage.
In 2008, major damage occurred due to the floods from April, May, July (Maramure¸ s County) and May (Satu Mare County). Watercourses on which damage has
been reported were: Tisa, Vi¸ seu, Iza and Mara from Maramure¸ s County, plus the
Barlogelor Valley and Lechincioara in Satu Mare County.
297
In the Cri¸ suri river basin, floods are formed in all seasons of the year, depending on
the moisture intake brought by the air masses. The floods of 1970 had as a triggering
factor a heavy rainfall regime. The whole period from January 1 to May 10 was rich in
rainfall, with double quantities of water in relation to the normal multiannual values,
which caused the infiltration of at most 20–25% of the amount of water lost, the rest
entering the drainage process. The value of damage to the Cri¸ suri catchment area
amounted to more than 128 million euro at present (390 million lei in 1970). Between
May 7 and 9, 1989, in the river basins of the Barc˘ au, Cri¸ sul Repede and Cris , ul Negru
rivers, large amounts of precipitations fell, which overlapped over a period when
the soil was soaked with water, which caused most of the rainfall to contribute to
surface leakage. The floods formed between December 1995 and January 1996 had
the following causes: warming and rapid melting of the snow layer, especially in
mountainous and hilly areas, the disappearance of ice on rivers, liquid precipitations
marked quantitatively in the conditions of a frozen soil, unable to allow infiltration,
and water leakage on the slopes to the riverbeds.
Among the most famous floods in the Some¸ s—Tisa hydrographic area, there are
mentioned 1970, 1974, 1975, 1978, 1979, 1980, 1981, 1989, 1993, 1995, 1998, 2000,
2001, 2006 and 2008.
In the 1970s, floods were due to long-lasting heavy rainfall, which exceeded the
critical thresholds, causing the overflow of most rivers. In 1974, during the June-July
period, the floods occurred due to precipitations that far exceeded the average annual
precipitation in the watersheds Tur, Some¸ s, Crasna and Vi¸ seu.
In 1980, the floods were due to a repeated fall on a saturated soil, which exceeded
the critical thresholds, exceeding the defense rates on most of the watercourses in
this hydrographic area. On the Almas , , Crasna, Agrij, S˘ alaj, Budac, Zal˘ au, Olpret, Iza
and Batarci rivers, have overcome 2–3 times the hazard. On the Tur river, the hazard
was exceeded 4 times. The most important floods occurred in July when at the Sighet
Weather Station were registered 178.6 l/m
2 , at Ocna S , ugatag 158.6 l/m
2 , 146.5 l/m
2 at
the Negre¸ sti Oa¸ s pluviometric station, 137.5 l/m
2 at Vama and 116.9 l/m
2 at Turulung.
On the lower courses, due to the small slope, the floods lasted up to 7 days.
In 1981, the floods were due to precipitation, melting of snow and leakage on the
slopes, causing on most of the watercourses in the basin, rises in levels that have
exceeded the defenses. In 1995 and 2001, the floods occurred in December due to
precipitation in the form of rain and rapid melting of snow, favoring the emergence
of flood waves on S , omesul Mare and tributaries, Tisa and tributaries, L˘ apus , , Cavnic,
Tur and tributaries. In 1998, the floods from June were due to particularly abundant
precipitation that caused rich leaks on the slopes and in 2006, on the Ili¸ sua river, a
tributary of the Somesul Mare river, was a rapid flood, in June, as well. The total
duration of the flood was 34 h and the maximum flow about 212 m
3 /s (Cristes , tii
Ciceului hydrometric station). This has caused 13 human lives and a lot of material
damage.
In 2008, major damage occurred due to the floods from April, May, July (Maramure¸ s County) and May (Satu Mare County). Watercourses on which damage has
been reported were: Tisa, Vi¸ seu, Iza and Mara from Maramure¸ s County, plus the
Barlogelor Valley and Lechincioara in Satu Mare County.