15.12.1998

Content

Factors and causes that in combination increase of scales of the flood in November 1998 in Zacarpatye

Natural causes of the flood

Anthropogenetic causes of the flood

Insufficient readiness to extraordinary situations

Non-fulfillment in full scope of complex program of anti-flood measures in 1994-2000

Analysis of natural conditions and factors

An observation and analysis of findings of long - time researches shows that beginnings of floods

and other dangerous natural phenomena in Zacarpatye comes as interaction result of series of natural and anthropogenetic factors

The hydrometeorological factors are the most important among them. They are intensive and long rains over all area of watershed, a kind of water entering to river- beds. These factors in combination with peculiarities of water scoops surface (steepness and size of beach approaches, insignificant bedding depth of maternal breeds, dismembering of relief) play a dominating role for creating conditions for catastrophic natural phenomena, including floods, mudflows and soil dislocation. These processes create precarious situations that intensify while jointed with intensive long precipitation and rapid snowmelt.

The mudflows are observed in mountain region and form in the main during summery period at the time of intensive rains. However in Zacarpatye mudflows are possible in winter, when snowmelt is accompanied by occasional or mixed precipitation.

In accordance with genetic classification of the region territory is picked out a south - west dangerous mudflow region (the basin of right-bank tributaries of the Tisa river).

It is necessary to mark that in Carpathy there is the maximum density of drainage system in Ukraine. For mountain Carpathian small rivers the floods of different genesis are typical over all year.

The region territory is broken by drainage network of high density. A mean density of drainage network is 1,7 of km/km2. In all there are 9426 small rivers and flows by summary length 19793 km in the region. 153 the small rivers have general length 3545 of km. From them four rivers (Tisa, Borzhava, Latoritcya and Uzh) have length over 100 by km each.

All Zacarpathian small rivers belong to Tisa basin, the most Danube tributary. Within the region the Tisa length is 201 km from the total length 966 km. On the region territory it has basic right tributaries: Kosovska (41 km) small river, Teresva (56 km), Tereblya (91km), River (92 km), Borazhava (106 km). The watershed of the Tisa river that within the region is 12760 km 2 (the total area is 156400 km2 ).

The Ukrainian Carpathy and Zacarpathya belong to shower dangerous regions of Europe. That’s why here always there is a potential danger of flood beginning.

The floods on Carpathian small rivers are repeated 4-5 times a year. Frequency of their forming in a long - time cut subordinates to regulars that become apparent in alternation of big and small water periods. Namely in the big water periods floods have an imminent disaster disposition.

In 1990 - 1999 there is a big water period that changes the small water period (1982-1990. This time the high floods were forming not only in Zacarpathya ( in 1992,1993 in Zacarpathya; in 1993 in Pripyat; in 1994 in Germany; in 1997 in Poland, Chekhia, Slovakia, Germany, the Dnister basin, in1998 in Zacarpathya, the Dnister basin, Slovakia, Germany). For post-war time in Zacarpathya there is a series of high floods that caused losses in economy. This is the floods of 1947, 1957, 1970, 1980, 1992(two), 1993, 1995(two).

A catastrophic rainfall destroying flood that formed during period from 4 to 8 November this year on favourable hydrometeorological subsoil, for its descriptions and size of losses reached, and in some points exceeded all previous floods for observation period.

Development and disastrous effects of the flood marked by such basic factors:

High previous volume of runoff rivers.

Excessive moistening of soils.

Intensive long precipitation forming water levels rising in small rivers on November beginning.

State of economic mastering and utilization of natural resources of the region.

A summer and autumn seasons in Zacarpathye were rainy. By the observation data of meteorological stations, all without exception, a monthly precipitation exceeded norm. And for August and October there has been from 1,3 to 1,5 of precipitation norm.

Summary precipitation, for data of meteorological stations and hydrological posts of State Hydrological and Meteorological Committee, 4-5 November was 45-75 mm, in Latoritca, Borzhava, Teresva, Tisa basin items was 90-120 mm, in the Rika riverhead was 207 mm. The daily precipitation sums reached monthly norm, and in series of points in November were 1,5 of norm.

The flood started 4 November on background previous rainfall flood formed on Zacarpathya small rivers at the end of October.

By comparison with water level on the beginning of November flood its general increasing at control sections of gauges reached 1,7

3,6 m, on the Tisa river near Tyachev and Vilok, on the Latoritca river near Mukachev - 4,1 - 6,1 m. Water levels at 13 ranges exceeded the historical maximums.

Over all the regional territory on small rivers and brooks in settlements a considerable local flow formed, that caused low places deluge.

A water protection and water regulating role of forest ecological system shows by moisture hampering by tops and trunks, transpiration, evaporation from soil surface and shoots and soil absorption. Taking into consideration an excessive moistening late autumn period and completion of vegetation period that role was considerably decreased. An inspection of the flood consequences gives the opportunity to state, that intensive floods were observed on watershed of different wooded terrain. So, watershed of the Rika river up to Mizhgir’ya has 45 % of wooded terrain, watershed of the Tereblya river up to Kolochava has 64 %, of the Chorna Tisa river up to Yasin has 75 %. Maximum water levels in these rivers 5 November independently from wooded terrain on 1,8 - 2,6 m exceeded the pre - flood indexes. Even by entire wooded terrain by mature beech forest near the sanatorium "Svalyava" an unprecedented flood was formed, that caused destroying and carrying out the disintegrated rock formation on concrete constructions of sanatorium in accordance with this inspection, some regularity as for accordance of mudflows, soil dislocation and other damage phenomena with woodsy whether unwoodsy plots, or felling places, is not observing.

Factors and causes that in combination increase of scales of the flood in November 1998 in Zacarpatye

Natural causes of the flood:

1) difficult hydrometeorological situation (precipitation above norms, their intensity and duration) after rainy summer and autumn, that caused soil saturation with moisture and decrease its water absorption and water permeable capacity;

2) geological, orographical and hydrogeological conditions that constantly give rise to forming of various soil dislocations, landfalls and mudflows in mountain regions and close-fitting to them:

high power potential of mountain relief that gradually rise in connection with contemporary mountains rising;

permanent making more active instability of separate parts of mountain massifs in consequence of seismic entrails activity and their uneven tension in separate tectonic zones and knots joint with

active erosive processes;

peculiarities of hydrogeological conditions decreased cohesion of separate parts of breeds blocks in conditions of active influence of gravitation forces;

lowering of breeds solidity composing the slopes, in connection with their weathering;

3) holding up vegetation, falling off of foliage from trees and withering grasses on meadows, period of sharp decreasing of vegetable cover ability to detain rain-waters, their reverse evaporation into atmosphere and holding up transpiration that is powerfull moisture transformer.

Considerable beach approach stepness, near bedding of watertight mountain breeds creates the extraordinarily favourable conditions for fast water flowing down. These processes create precarious situations while jointed with mudflows and rapid snowmelt.

4) air temperature rising after previous snow-falls caused snowmelts on top parts of mountain slopes and additional receipt water to mountain rivers;

5) high volume of runoff of small rivers before flood, connected with the flood passing at the end of October.

Antropogenetic floods causes:

A flood consequences size is influenced by antropogenetic interventions, not corresponding with mountain conditions that caused water economy, forestry and agriculture during almost 200:

violation of execution technology of technical crops works that were in the region up to 80th years for improvement of natural hay-making lands and pastures. That’s why trees and bushes together with fertile soil layer rolled up into banks by heavy engineering and mechanisms, that caused to water erosion and to augmentation of surface outflow;

Slopes destroying in mountain regions where floods form.

destruction of forests near meadows, creation of enormous (in Ukrainian Carpathy - over 100 thousand hectares) alpine meadows after forests felling, specially on Polonynski mountain range (Rivna, Borzhava, Krasna, Svidovetc and other meadows.), lowering of top forest level from 1400 to 1200 metres;

a long use meadows for pastures made worse water-physical properties and reinforced augmentation processes of surface flow at riverheads;

lack of storage lakes on mountain rivers, appointed first of all to regulate river flow during periods of intensive precipitation and possible floods;

Wood transportation by logging is using obsolete technologies, that causes a series of negative phenomena, such as: soil erosion, damage of shoots. In result all that caused to decrease of water regulation and polliting of small rivers;

Unfounded output of gravel and sand materials from small rivers river-beds and in their valley led to increasing of erosive river-bed processes, river-bed deformation, that is a threat for economic objects and hydrotechnical facilities;

Non-compliance with the management regime in water- protective zones and protective riverside stripes of small mountain rivers. They are built up to their river- beds. Bushes that are near river – beds, destroyed; a cattle pastures on beach approaches adjoining them;

building at settlements was in the main according to decisions of general plans with regard for being engineer-protective facilities or foreseen by projects, however lag of building temps of protective facilities, and also their destruction during the flood in towns Uzhgorod, Mukachev, Tyachiv, Rakhiv, Irshava and in villages of Berigivski region (Vary, Tcentralne, Orosieve, Kvasove), of Vinogradivski region (Bobove, Chepa, Chornotysiv, Tekove, Korolyovo), of Rakhivski and Tyachivski regions (Dubove, Teresva) and other regions lead to difficult consequences;

placing of dwelling-houses on ways of mountain streams, in soil dislocation places and in dangerous mudflow plots in villages of Tyachivski region (Ruska Mokra, Ust-Chorna, Lopukhiv, Komsomolske), and also unwarranted building of dwelling-houses on dangerous plots destroyed by flood in Kolochava-Mereshor of Mizhigirski region;

incomplete execution of measures on engineering protection of watershed territories, foreseen by scheme of region planning of Zacarpathian region, of projects of Vinogradivski, Khustski, Irshavski and Uzhgorodski regions; lack of proposals as for engineer protection of territories in projects of regional planning of Tyachivski, Mizhigirski and Velykobereznyanski region and in the most part of planning projects of settlements;

imperfection of separate obsolete general plans of settlements and projects of regional planning, where, as a rule, the lines of catastrophic flooded areas and riverside protective of small rivers and brooks not are not marked.

Note. Historic planning and building of settlements in Zacarpathian took place in lack conditions of territories suitable for agriculture.

Insufficient readiness to extraordinary situations:

Hanging dams in small river river- beds were created by gravel and shingle sediments that congested during annual floods and in proper time were not eliminated.

Building of territory on the flood zone by floods of frequent repetition, without regarding for readiness level of protective facilities;

lack of legislative, normative and legal base relative to insurance of inhabitation in conditions of technogenic and natural risk;

insufficient implement by local authority organizations the water protective measures on mountain small rivers, namely: cleaning of undermined trees, rhizomes, brushwood. Even by not high floods this mass forms temporal hanging dams that obstruct the water carrying bridges ranges and facilities and cause the sharp local water-levels rises, and then the destruction of facilities and additional flood wave;

insufficient determination of concrete borders of nature protective zones and riverside protective stripes, as this calls for Water Ukraine code;

insufficient attention to concordance of building technical conditions with local organizations of water economy;

insufficient methods work of mass media as for increasing of ecological and general culture of inhabitants;

insufficient development of a peoples notifying system.

However because of very irregular and insufficient financing from the beginning of the measures implement, proposed by the Program, only 33 km embankments (17%) were built, 20 km small rivers banks (39%) were fortified, 41km their river-beds (25 %) were adjusted.

Budget financing for anti-flood measures annually increased and reached the critical situation. In 1998 a neither object was put into operation. The funds are not sufficient even for the damage liquidation of protection facilities that are building now.

Non-fulfillment in necessary scope of complex Program of anti-flood measures during 1994-2000 on Zacarpathian region territory is one of causes of heavy consequences of the catastrophic flood.

GENERAL RESOLUTION.

Zacarpathian Noverber flood of 1998 is foremost natural calamity conditioned simultaneous joint actions of natural factors (humid summer, autumn and soil moistening, ceasing of vegetation and increasing of water transformation ability of vegetable cover, powerful showers and snowmelts), the consequences of which were reinforced by factors antropogenetic influence.

The most dangerous regions of active geologic processes in Zacarpathian are Rakhivskii region (the villages: Kobyletzka Polyana, Kosivska Polyana, high way Rakhiv – Bychkiv and others) Tyachivskii region (settlements: Ust – Chorna, Vilkhivtzy, villages: Ruska Mokra, Lopukhiv, Komsomolske and others). It is also Mizhigirskii region (near Mizhgir’ya town, villages: Synevir, Kolochava and others), Volovetzkii region (villages: Guklyvyi, Skotarske, Verb’yache and others), Khutskii region (villages: Velyatino, Oleksandrivka, Vilshany and others), Irshavskii region (villages: Ilnytzya, Lusuchevo and others).

A coming cycle of increasing soil dislocation and mudflow processes forecasts during spring flood period. Their further partial increasing is possible already during winter thaw period. That’s why it is necessary permanently to observe dangerous mudflow beach approaches, first of all not far from settlements, along communications and dangerous mudflow places.

The period of high volume of runoff is very possible on small rivers in Ukraine during next 8 – 10 years, first of all in western region, with its repeated high floods.

It is necessary to underline, that coincidence of negative natural factors that lead to extraordinary situation in November 1998, is not maximum. Analysis of paleogeologic and paleogeographic processes shows it is necessary to be ready to considerably greater negative extraordinary situations, associated with high volume of runoff as well as with dangerous exogenous and endogenous geologic processes in Zacarpattye.

Basic methods for prevention of the being threat of catastrophic effects of next possible floods is hydrotechnical Zacarpathian territory arrangement, implement of ecologically safe technologies using in water economy, forestry and agriculture, monitoring of exogenous geologic processes.

On watersheds of Zacarpathian small rivers it should be arranged economic activity, as well as within the water protection zones and littoral protective stripes that ruin from floods it should be implemented engineering and biotechnical measures. It is necessary to renew the technical exploitation service of mountain rivers with development of normative and legal documents.

It is necessary to implement new orientation measures for economic complex of mountain Zacarpathian part as for development of ecologically safe kinds of activities. It applies equally to expansion recreation forest using and augmentation of area reserving territories. For creation of favourable conditions for development tourist and recreation industry it is necessary to create the special ecological zones in the Tisa basin riverhead, first of all on Rakhivski region territory.

For liquidation of flood catastrophic effects in November 1998 in Zacarpathian region and for prevention of their ruinous action in future it is necessary to develop a complex State program for Carpathian region, that is ought to include:

improvement of legal base;

engineering-technical arrangements;

organizational arrangements;

scientific and technical providing;

financial and economic basing of arrangements;

increasing ecological consciousness and information of inhabitants;

international cooperation.

The Ministry of Environmental Protection and Nuclear Safety.

The Ministry of Extraordinary Situations

The Ministry of Economy

The State Committee of Building

The State Committee of Geology

The State Committee of Hydrology and Meteorology

The State Committee of Water Resources

National Academy of Sciences of Ukraine