The floods in Moravia and the Oder in July 1997 were a large-scale natural disaster that, according to Povodí Moravy, s. p., affected the basins of the Morava, the Oder and the upper Elbe and was marked by an extremely rapid and destructive course.[1]
The floods in Moravia and the Oder in July 1997 affected areas in the basins of the Morava, the Oder and the upper Elbe.[1] According to Povodí Moravy, s. p., it was a catastrophic flood with an unexpectedly rapid and torrential course, in which the beds of watercourses in the upper reaches were almost completely destroyed.[1] The water level reached a height whose areal extent and depth of inundation exceeded all values recorded until then.[1] The flood carried such a quantity of sediment that, according to the operator of the watercourses, it lay beyond the possibilities of measurement and monitoring.[1]
Causes and course
The flood was caused by exceptionally intense rainfall.[1] Daily precipitation totals reached up to 230 mm and in places exceeded 600 mm over five days.[1] The highest totals were measured between 4 and 8 July 1997.[1] At the Raškov station on the Morava, peak discharges corresponded to as much as an 800-year flood.[1] On the stretch between Kroměříž and Uherské Hradiště alone, 350 to 400 thousand tonnes of sediment were deposited.[1] Povodí Moravy administered almost 4,000 km of watercourses, of which roughly 2,000 km, half, were affected by the July flood.[1] The flow was so strong that it carried even stones more than one metre across.[1]
According to Povodí Moravy, reservoirs markedly reduced peak outflows compared with inflows. At the Slezská Harta waterworks, managed by Povodí Odry, the inflow reached 192 m³/s while the outflow did not exceed 12 m³/s.[1] At the Vír waterworks, managed by Povodí Moravy, the inflow reached 167 m³/s and the outflow did not exceed 38 m³/s.[1]
Consequences
In the Olomouc Region, 110 municipalities and towns were affected by flood inundation.[1] Evacuations took place in 38 municipalities, and 7,850 people were evacuated in total.[1] In the Olomouc Region, 24 people died in the flood.[1] The inundation covered an area of 434 km² with an average depth of 2.5 to 3.0 metres.[1] The discharges reached clearly exceeded the values of a 100-year flood.[1]
Damage repair and flood protection measures
Povodí Moravy, s. p. carried out, in the years 1997 to 2004, the repair of flood damage to watercourses and other water-management property, with total budgeted costs of CZK 2.5 billion.[1] In the Olomouc Region, 152 projects were carried out at a cost of CZK 1.051 billion, which represented 43% of the total flood damage.[1]
Since 1999, when the so-called zero stage of construction of flood protection measures began, the state invested through Povodí Moravy CZK 4.7 billion in flood protection structures up to 2018, said the company's director general Václav Gargulák.[2] According to his statement, it was divided by stages: stage 0 – CZK 184 million, stage 1 – CZK 1,367 million, stage 2 – CZK 1,770 million, stage 3 – CZK 1,400 million and stage IV – CZK 1,100 million.[2] For construction within the ongoing stage IV of the subsidy programme Support for Flood Prevention, a further CZK 1.1 billion was planned, according to Gargulák's statement.[2] Funds for these measures were provided by the Ministry of Agriculture under the programme Support for Flood Prevention.[2]
Since the floods of 1997, according to Povodí Moravy, more than twenty large flood protection measures and dozens of smaller modifications and structures have been carried out.[1] According to the company, the most significant include stages I and II.A of the protection of Olomouc and measures on the upper Morava from Hanušovice through Bohutín, Chromeč, Postřelmov, Sudkov, Lesnice and Leština to Moravičany and Mitrovice, which according to Povodí Moravy proved their worth in the flood of 2010.[1] In the territory of the Olomouc Region, almost thirty large flood protection measures were carried out; according to the company, the most significant include stages I, II.A and II.B of the flood protection of Olomouc.[2] Construction of stage II.B of Olomouc's flood protection measures was to begin in the autumn of the year in which Povodí Moravy published its report on twenty years since the flood.[1]