CZECH HYDROMETEOROLOGICAL INSTITUTE Central Forecasting Office. Drought information

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Myles Flowers
8 years ago
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1 Issued: 8-AUG-2008 CZECH HYDROMETEOROLOGICAL INSTITUTE Central Forecasting Office Drought information July 2008 was normal in the meaning of average temperature (+0,7 C above normal) as well as precipitation (1 % below normal) in the Czech Republic. However more precipitation has occurred in the eastern part of the area. Majority of precipitation events were connected to thunderstorms. That means that its spatial extent was usually relatively small and its duration was rather short. That kind of precipitation is not suitable for infiltration and underground water recharge. Precipitation caused temporal increase of water levels of streams in Odra river and Bečva river basins, while water levels of other streams in the Czech Republic were stable or slowly decreased. However due to precipitation a top soil moisture generally did not reach critical values of drought risk (fig.1) and wild fire risk (fig.2) except southern Moravia, eastern Bohemia and some areas in central Bohemia. Fig. 1 Drougth risk: 1 very low, 2 - low, 3 - moderate, 4 - high, 5 very high. Composite result of soil moisture measurement, computed soil water balance and evapotranspiranspiration balance.

That means that its spatial extent was usually relatively small and its duration was rather short. That kind of precipitation is not suitable for infiltration and underground water recharge.

2 Fig. 2 Wild fires risk: 1 very low, 2 - low, 3 - moderate, 4 - high, 5 very high. Surface streams and rivers discharges equal mostly to % of long time average for August (Q VIII ). Mountainous rivers and streams have % Q VIII. On the other hand some smaller lowland and middle altitudes streams in Bohemia discharge correspond only to 5-20 % Q VIII. Orlice river basin, Výrovka river, lower Cidlina River, Lomnice river, Skalice river and other could be named as examples. Value of so called Q 355 is considered to be drought threshold for river discharge. Q 355 represents about 3-5 % of historically lowest observations. Rivers below that threshold are indicated by white circle on the web presentation of CHMI ( fig.3 and table 1. Fig. 3 White dots indicate water gauges bellow the threshold for drought.

Orlice river basin, Výrovka river, lower Cidlina River, Lomnice river, Skalice river and other could be named as examples.

3 Tab. 1 water gauges bellow the threshold for drought RIVER WATER GAUGE LEVEL DISCHARGE N/M LABE JAROMER METUJE KRCIN D.ORLICE KOSTELEC no TREBOVKA HYLVATY T.ORLICE CERMNA no ORLICE TYNISTE no DEDINA CHABORY DEDINA MITROV CHRUDIMKA SVIDNICE CHRUDIMKA NEMOSICE DOUBRAVA ZLEBY CIDLINA SANY MRLINA VESTEC VYROVKA PLANANY JIZERKA D.STEPANICE JIZERA ZELEZ. BROD JIZERA PREDMERICE LABE BRANDYS nl NEZARKA RODVINOV NEZARKA LASENICE LUZNICE KLENOVICE OTAVA SUSICE BLANICE HERMAN OTAVA PISEK LOMNICE D. OSTROVEC SKALICE VARVAZOV KOCABA STECHOVICE SAZAVA ZRUC ns ZELIVKA SOUTICE BLANICE RADONICE SAZAVA NESPEKY MZE STRIBRO UTERSKY P TRPISTY RADBUZA CESKE UDOLI USLAVA KOTEROV KLABAVA NOVA HUT LITAVKA BEROUN ODRAVA JESENICE SVATAVA SVATAVA TEPLA BREZOVA PLOUCNICE BENESOV np LUZ.NISA LIBEREC SMEDA FRYDLANT MORAVA MORAVICANY ROMZE STRAZISKO DREVNICE ZLIN MOR.DYJE JANOV JIHLAVA DVORCE JIHLAVA PTACOV OSLAVA OSLAVANY DYJE NOVE MLYNY Lower Elbe water level is bellow the limit for full navigation (275 cm) between Usti nad Labem and Czech-German border since May (fig.4). Recent water levels are between 140 and 145 cm. That means maximal possible ship sink of cm not enabling economical operation of navigation.

07 365 DEDINA MITROV 14 0.07 365 CHRUDIMKA SVIDNICE 10 0.54 355 CHRUDIMKA NEMOSICE 38 0.84 355 DOUBRAVA ZLEBY 19 0.20 355 CIDLINA SANY 5 0.12 364 MRLINA VESTEC 4 0.07 364 VYROVKA PLANANY 10 0.

4 3 vodní stav v Ústí nad Labem (m) : : : : : : : : : : : : : : : : : : : : :00 HLADINA LIMIT PLNOSPLAVNOSTI Fig. 4 - Ústí nad Labem water stage since May 2008, red water stage, blue full navigation limit. Underground water levels and yield decrease since spring months. Most of the observation boreholes and springs are below normal and belong to 37 % (boreholes) resp. 29 % of lowest historical observations. These values are comparable to those measured in 2007 drought (fig.5) % prameny Fig. 5 Course of underground water levels and yields in the meaning of probability distribution curve rank since July % means average, lower values indicate drought. There are significant regional and local differences. While boreholes and spring in Silesia and Bohemian-Moravian Highland are close to the normal, central Bohemia and south Moravia show drought (belongs to 15 % of lowest historical observation). vrty

4 - Ústí nad Labem water stage since May 2008, red water stage, blue full navigation limit. Underground water levels and yield decrease since spring months.

5 Fig. 6 Springs yield with respect to July long time normal. Red very low, pink low, white normal, pale blue high, blue very high. Fig. 7 Boreholes water level with respect to July long time normal. Red very low, pink low, white normal, pale blue high, blue very high.

6 Future outlook Long-range meteorological forecast is for normal precipitation and temperature during August. Medium-range meteorological models assume possible more frequent precipitation in the middle of August, however quantitative prediction is not reasonable so far. If the forecast full fill the drought risk and wild fire flood risk will decrease. In the case of torrent precipitation of more than 30 mm some slow increase of water level of small streams could be also expected. Underground waters are expected to be stable or continue in slow decrease.

not reasonable so far. If the forecast full fill the drought risk and wild fire flood risk will decrease.

Drought in the Czech Republic in 2015 A preliminary summary

Drought in the Czech Republic in 2015 A preliminary summary October 2015, Prague DISCLAIMER All data used in this preliminary report are operational and might be a subject of change during quality control.