Abstract:The paper deals with the macrostructural and microstructural landscape changes in six selected microregions in Moravia and eastern Bohemia. Changes of the landscape macrostructure were evaluated based on the statistical data from 1845, 1948, 1990 and 2013. Changes of the landscape microstructure were compared on the base of old maps, aerial images and field experiences. According to the available data the area of an arable land was the largest in 1845. Since then it has been decreasing -more in mountain areas, less in lowland ones where it was replaced by forests, grasslands and urban areas, depending on the vegetation period, physical character and vicinity of urban centres. Results show that the microstructure recorded great changes during the communist period: large expanses of fields, irrigation and drainage measures, windbreaks, non-rural buildings in the countryside. Contemporary changes are connected mostly with urbanisation of the landscape.Key words: landscape changes, macrostructure, microstructure, the Czech Republic Souhrn: Příspěvek se zabývá změnami makrostruktury a mikrostruktury krajiny v šesti vybraných mikroregionech Moravy a východních Čech. Makrostruktura krajiny byla hodnocena na základě statistických dat za léta 1845, 1948, 1990 a 2013. Změny krajinné mikrostruktury byly srovnány na základě starých map, leteckých fotografií a zkušeností z terénu. Orná půda zaujímala největší plochu v roce 1845. Od té doby jejich rozloha klesá -více na vrchovinách, méně v nížinách. Orná půda je nahrazována lesy, trvalými travními porosty a urbanizovanými územími v závislosti na období, fyzickogeografickém charakteru území a blízkosti urbánních center. Z výsledků srovnání vyplývá, že mikrostruktura zaznamenala velké změny v komunistickém období tvorbou rozsáhlých lánů polí, zavlažovacích a odvodňovacích opatření, větrolamů, nerurálních budov na venkově. Současné změny jsou spojovány hlavně s urbanizací krajiny.
KOZLOVSKÁ, S., TOMAN, F.: Antecedent precipitation index evaluation at chosen climatological stations. Acta univ. agric. et silvic. Mendel. Brun., 2010, LVIII, No. 4, pp. 135-140 The water retention capacity of a landscape, usually measured for a catchment basin, is a very important and decisive characteristic to identify the runoff amount from the catchment area and, in consequence, for antierosion and fl ood protection measures. Besides, creating water reserves in the landscape and keeping the water in them is also rather important. Soil humidity contributes to the calculation of potential water retention through modelling the runoff amount and peak discharge from the catchment basin within an area not larger than 5-10 km 2 . This method is based on curve number values (CN), which are tabulated according to hydrological characteristics of soils, land use, vegetation cover, tillage, antierosion measures and soil humidity, estimated as a 5-day sum of preceding precipitation values. This estimation is known as the antecedent precipitation index and it is divided into 3 degrees -I, II, III. Degree I indicates dry soil but still moist enough to till, whereas degree III means that the soil is oversaturated by water from preceding rainfall. Degree II is commonly used in this context as the antecedent precipitation index. The aim of this paper is to obtain real antecedent precipitation index values in given climatological stations (Brno, Dačice, Holešov, Náměšť nad Oslavou, Strážnice, Telč -Kostelní Myslová, Velké Meziříčí, Znojmo -Kuchařovice) for the period of years 1961 -2009. Daily precipitation sums higher than 30 mm were considered to be the best candidate for such precipitation value since this occurs approximately once a year in studied areas. The occurence of these sums was also analysed for each month within the growing season (April to October). The analysed data was tabulated by climatological stations in order to check the real occurence of all antecedent precipitation index degrees within the studied period. Finally, the eff ects of diff erent antecedent precipitation index values on the potential water retention capacity of the sample catchment basin were calculated to compare the results. precipitation, water retention capacity of a landscape, runoff , CN (curve number), antecedent precipitation index Retenční schopnost krajiny a možnosti jejího zvyšování jsou v současnosti velmi aktuálním tématem. Je snahou zadržet srážkové vody v krajině co nejdéle, a to ze dvou hlavních důvodů: jednak při vytváření zásob vody v krajině pro správné fungování ekosystémů, jednak jako zadržení vysokých objemů odtoku při přívalových deštích, tedy ochrana povodí a níže ležících oblastí před povodněmi.Retence vody je vyjádřením přirozené nebo umělé dočasné schopnosti zadržet vodu v prostředí.Retenční schopnost je funkcí reliéfu, vegetačního krytu, půdně-fyzikálních charakteristik, parametrů vodních toků, vodních nádrží a poldrů. Retence vody je významným činitelem ovlivňujícím transformaci srážek v odtok z povod...
The sum of design precipitation of a selected repetition period, provided that it is evenly distributed over the river basin area, is a basic input for the calculation of the direct outflow volume by the curve number method. It is necessary to determine the design precipitation for each location using the statistical methods and the longest available data series on daily precipitation sums, or more specifically their annual maximums. This paper deals with the determination of design precipitation from data of eight stations of the Czech Hydrometeorological Institute for the period 1961 - 2013. From a series of annual maximum values of daily precipitation sums, N-year design precipitations were calculated using two methods (Gumbel and generalized extreme value distributions). The conformity of both models with empirical distribution of values was statistically tested to evaluate which of the models gave more accurate results. In these cases, it was more appropriate to use the generalized extreme value distribution. Finally, the newly calculated characteristics were compared with the design values used by Šamaj et al. (1985), where significant differences were found.
Due to the growing awareness of the extent of degradation of agricultural soils as a result of water erosion, increased attention is paid to the establishing of effective erosion control measures based on reliable and timely input data. When determining the vulnerability of farmland to water erosion, the determining factor is erosively dangerous rains, which are defined as totals over 12.5 mm and intensities of more than 24 mm.h-1. This paper analyses the dangerous erosion rainfalls using data on rainfall intensities of precipitation monitoring network of the company Brněnské vodovody a kanalizace, a.s. (BVK) in the city of Brno. At first, we have set up 14 rain gauge stations distributed over an area of approximately 105 km2 and set basic indicators of individual rainfall episodes. Then we have analysed their maximum 30-minute intensity, kinetic energy and then determined the factor of erosion efficiency. We have found out a significant spatial variability of these variables throughout the area of the city of Brno. The R-factor analysis revealed that the average annual values of R-factor were the highest in the south-eastern part of the city of Brno while the least dangerous erosion rainfalls occurred in the west.
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