This paper presents the results of testing the applicability of the MIKE Basin model for simulating the efficiency of scenarios for reducing water pollution. The model has been tested on the Olšava River Basin (520 km2 ) which is a typical rural region with a heterogeneous mix of pollution sources with variable topography and land use. The study proved that the model can be calibrated successfully using even the limited amount of data typically available in rural basins. The scenarios of pollution reduction were based on implementation and intensification of municipal wastewater treatment and conversion of arable land on fields under the risk of soil erosion to permanent grassland. The application of simulation results of these scenarios with proposed measures proved decreasing concentrations in downstream monitoring stations. Due to the practical applicability of proposed measures, these could lead to fulfilment of the water pollution limits required by the Czech and EU legislation. However, there are factors of uncertainty that are discussed that may delay or limit the effect of adopted measures in small rural basins.
There is a great uncertainty about the effect of land use change on grassland ecosystem in the Tibetan Plateau. Net ecosystem carbon exchange (NEE) was measured for native alpine meadow with winter grazing (NAM), abandoned cropland/pasture (APL), perennial Elymus nutans (PEN), and annual oat pasture (AO) on the Tibetan plateau, during the growing seasons in 2009 and 2010 using a transparent chamber technique (Licor-6400). AO significantly decreased annual average NEE by 21.6, 23.7, and 15.7% compared to PEN, NAM, and APL during the growing season in 2010. Compared to PEN, NAM, and APL, AO significantly decreased average ecosystem respiration (Re) by 21.1, 52.3, and 39.3%, respectively, during the growing season in 2009. Soil moisture and total aboveground and belowground biomass together explained 39.6% of NEE variation and 71% in gross primary productivity variation. Soil moisture and belowground biomass explained about 83.1% of the Re variation. Our results indicated that it is possible to convert APL to PEN in the region because it could result in a higher NEE together with higher forage production compared to AO., C.-Y. Luo, X.-X. Zhu, S.-P. Wang, S.-J. Cui, Z.-H. Zhang, X.-Y. Bao, L. Zhao, Y. Li, X.-Q. Zhao., and Obsahuje seznam literatury
The paper provides an overview of recent hydrology-related research conducted by the Research Institute for Soil and Water Conservation and its predecessors. Research catchments and similar research sites, mostly under agricultural land use, are described. The principal catchments, located in Central and East Bohemian peneplains and highlands (Cerhovický potok near Hořovice, anonymous stream above Černičí near Čechtice, Kopaninský tok near Pelhřimov, and Žejbro near Skuteč with its subcatchments) are described in a greater detail with reference to web presentations (http://www.hydromeliorace.cz/povodi/ index.html). The second part overviews the main research results obtained, prevailingly during the last decade, in the field of catchment hydrology, water quality generation, agronomic measures for protection against nitrate pollution, the effect of tile drainage on extreme flows and water quality, soil water in the vadose zone with preferential flow and the landscape-ecological aspects of water resources protection. It is concluded that some problems could not be solved if the questions were not posed in a hydrological manner. The authors recommend to generalise empirical research results by modelling and to intensify connections between RISWC research and hydrological activities of other institutions. and Práce podává přehled novější historie výzkumu s hydrologickými prvky ve Výzkumném ústavu meliorací a ochrany půdy a v ústavech, které byly jeho předchůdci. Stručně popisuje jednotlivá malá výzkumná povodí a další výzkumné lokality, většinou se zemědělským využitím půdy. Hlavní výzkumná povodí, umístěná v oblasti středočeských a východočeských parovin a pahorkatin (Cerhovický potok u Hořovic, bezejmenný potok nad Černičím u Čechtic, Kopaninský tok u Pelhřimova a Žejbro u Skutče se svými podpovodími), jsou popsána podrobněji s odkazem na prezentace na webu (http://www.hydromeliorace.cz/povodi/index.html). Ve druhé části článku je podán přehled hlavních výsledků výzkumu dosažených převážně v posledním desetiletí v oblasti hydrologického režimu povodí a mechanismů tvorby jakosti vody, agronomických opatření na ochranu před dusičnanovým znečištěním, vlivu drenážních systémů na extrémní průtoky a jakost vod, vody v nenasycené zóně půdy s preferenčním prouděním a krajinně ekologických aspektů ochrany vodních zdrojů. Závěrem se konstatuje, že řadu problémů by nebylo možno vyřešit, kdyby otázky nebyly kladeny hydrologickým způsobem. Autoři doporučují zobecnit empirické výzkumy modelováním a zintenzivnit návaznost výzkumu VÚMOP na hydrologické aktivity jiných institucí.
Development of any area often leads to more intensive land use and increase in the generation of pollutants. Modeling these changes is critical to evaluate emerging changes in land use and their effect on stream water quality. The objective of this study was to assess the impact of spatial patterns in land use and population density on the water quality of streams, in case of data scarcity, in the Chugoku district of Japan. The study employed artificial neural network (ANN) technique to assess the relationship between the total phosphorous (TP) in river water and the land use in 21 river basins in the district, and the model was able to reasonably estimate the TP in the stream water. Uncertainty analysis of ANN estimates was performed using the Monte Carlo framework, and the results indicated that the ANN model predictions are statistically similar to the characteristics of the measured TP values. It was observed that any reduction in forested area or increase in agricultural land in the watersheds may cause the increase of TP concentration in the stream. Therefore, appropriate watershed management practices should be followed before making any land use change in the Chugoku district. and Rozvoj územia často súvisí so zintenzívnením využívania krajiny a produkciou znečistenia. Dôležité je modelovanie týchto zmien a ich vplyvu na kvalitu vody v tokoch. Cieľom štúdie je určiť vplyv priestorových zmien pri využívaní krajiny a zmeny hustoty osídlenia na kvalitu vody v tokoch v čase nedostatku vody v oblasti Chugoku, Japonsko. Pri riešení sa využívajú umelé neurónové siete (artificial neural network -ANN), prostredníctvom ktorých sa určuje vzťah medzi celkovým obsahom fosforu (TP) v toku a využívaním kajiny v 21 povodiach oblasti; tento model je schopný vypočítať TP v tokoch. Analýza neurčitosti výsledkov dosiahnutých pomocou ANN bola vykonaná metódou Monte Carlo; výsledky analýzy naznačujú, že predpovede pomocou metódy ANN sú štatisticky podobné meraným hodnotám TP. Bolo zistené, že redukcia lesnatosti a zvýšenie plochy poľnohospodársky využívanej pôdy v povodí môže viesť k zvýšeniu koncentrrácie TP v toku. Je preto potrebné pred zmenou vo využívaní krajiny prijať zodpovedajúce opatrenia v manažmente krajiny, ktoré budú minimalizovať negatívne dôsledky zmien využívania krajiny.
The impacts of land use and land cover on the transformation of the rainfall-runoff episodes were studied and analyzed with the utilization of HYDROG and HEC-HMS rainfall-runoff models in the Olše basin. Two episodes were selected - common regional rainfall with low antecedent watershed saturation and convective flash rainfall with higher watershed saturation. Watershed response was studied and modeled on separate levels of the forestation - actual forestation state, 50 % of forest land cover and 100 % of forest land cover. Results which were achieved with the utilization of the various methods of the hydrologic transformation in the watershed scale (Horton, SCS-CN) confirm the influence of forest land cover on the rainfall-runoff relations. Further research with the support of another methods and the continuous models such as GSSHA and MIKE SHE will allow the comparison of achieved results and possible generalization of them. and Pomocí srážkoodtokového modelování v modelovacím software HYDROG a HEC-HMS byla řešena otázka vlivu krajinného pokryvu na transformaci srážkové epizody v povodí Olše. Byly vybrány dvě srážkové epizody - regionální srážka v kombinaci s málo nasyceným povodím a přívalová srážka v kombinaci s nasyceným povodím - a byla zkoumána odezva povodí při simulované změně zalesnění povodí z aktuálního stavu na 50 a 100%. Dosavadní výsledky událostních simulací tento uvažovaný vliv potvrzují, a to i za použití různých metod hydrologické transformace na povodí (Horton, SCS-CN). Další výzkum a s pomocí jiných metod a kontinuálních modelů HEC-HMS, GSSHA a MIKE SHE umožní srovnání výsledků a jejich případné zobecnění.
Photosynthetic pathways (C3, C4, and CAM) and morphological functional types were identified for the species from vegetation in agro-pastoral ecotone, North Beijing. 792 vascular plant species (nearly half of the total species in the ecotone), in 66 families and 317 genera, were identified with C3, C4, and CAM photosynthesis (Table 1). 710 species (90 % of the identified species in Table 1) in 268 genera and 64 families were found with C3 photosynthesis, 68 species (9 % of the total identified species) in 40 genera and 7 families with C4 photosynthesis, and 14 species in 4 genera and 1 family with CAM photosynthesis. Gramineae is the leading family with C4 photosynthesis (43 species), Cyperaceae ranks the second (16 species) followed by Chenopodiaceae (5 species). The significant increase of C4 proportion (C4/total species) with land deterioration suggested the plants of this type are remarkably responsive to land use in the ecotone. 792 species were classified into nine morphological functional types and the changes of most of these types (e.g. perennial forbs (PEF), annual grasses (ANG), and annual forbs (ANF)) were consistent with habitats and vegetation dynamics in the agro-pastoral ecotone. Hence the photosynthetic pathways, combined with the morphological functional types, are efficient indications for studying the linkage between species and ecosystems in the ecotone. and X. Q. Liu, R. Z. Wang.