This study shows a comprehensive simulation of water and sediment fluxes from the catchment to the reach scale. We describe the application of a modelling cascade in a well researched study catchment through connecting stateof-the-art public domain models in ArcGIS. Three models are used consecutively: (1) the hydrological model SWAT to evaluate water balances, sediment input from fields and tile drains as a function of catchment characteristics; (2) the onedimensional hydraulic model HEC-RAS to depict channel erosion and sedimentation along a 9 km channel onedimensionally; and (3) the two-dimensional hydraulic model AdH for simulating detailed substrate changes in a 230 m long reach section over the course of one year. Model performance for the water fluxes is very good, sediment fluxes and substrate changes are simulated with good agreement to observed data. Improvement of tile drain sediment load, simulation of different substrate deposition events and carrying out data sensitivity tests are suggested as future work. Main advantages that can be deduced from this study are separate representation of field, drain and bank erosion processes; shown adaptability to lowland catchments and transferability to other catchments; usability of the model’s output for habitat assessments.
Soil erosion decreases soil fertility of the uplands and causes siltation of lakes and reservoirs; the lakes and reservoirs in tropical monsoonal African highlands are especially affected by sedimentation. Efforts in reducing loads by designing management practices are hampered by lack of quantitative data on the relationship of erosion in the watersheds and sediment accumulation on flood plains, lakes and reservoirs. The objective of this study is to develop a prototype quantitative method for estimating sediment budget for tropical monsoon lakes with limited observational data. Four watersheds in the Lake Tana basin were selected for this study. The Parameter Efficient Distributed (PED) model that has shown to perform well in the Ethiopian highlands is used to overcome the data limitations and recreate the missing sediment fluxes. PED model parameters are calibrated using daily discharge data and the occasionally collected sediment concentration when establishing the sediment rating curves for the major rivers. The calibrated model parameters are then used to predict the sediment budget for the 1994–2009 period. Sediment retained in the lake is determined from two bathymetric surveys taken 20 years apart whereas the sediment leaving the lake is calculated based on measured discharge and observed sediment concentrations. Results show that annually on average 34 t/ha/year of sediment is removed from the gauged part of the Lake Tana watersheds. Depending on the up-scaling method from the gauged to the ungauged part, 21 to 32 t/ha/year (equivalent to 24–38 Mt/year) is transported from the upland watersheds of which 46% to 65% is retained in the flood plains and 93% to 96% is trapped on the flood plains and in the lake. Thus, only 4–7% of all sediment produced in the watersheds leaves the Lake Tana Basin.
With regard to the water quality changes, the area of the Czech part of the Elbe River basin is extraordinarily dynamic. In the 20th century it experienced an enormous increase of load of pollution. Since the beginning of the 1990´s due to the political and economical changes we have witnessed a particularly intensive decrease in the emission volume and a related increase in water quality of watercourses. However, positive changes in the pollution load balance have occurred mainly in the biggest watercourses and these changes have not been accompanied by similar development in the whole river system. Using a newly created classification methodology the basic models of dynamics of water quality changes in the Elbe River basin have been derived. Based on GIS geostatistical analysis, regions with analogous water quality development trends have been defined for selected parameters and critical areas have been identified. It has become apparent that the prevailing part of the Elbe River basin has been experiencing a gradual increase in pollution. In addition, after a previous decrease, a number of watercourses experienced a recurrence of the increase in load. These areas are priorities for further development and the control of surface water protection against pollution. and Oblast české části povodí Labe je z hlediska změn kvality vody mimořádně dynamická. Díky intenzivnímu vývoji antropogenních aktivit a společenským změnám zaznamenala v průběhu 20. století nejprve enormní nárůst zátěže znečištěním, od počátku 90. let jsme naopak svědky mimořádně intenzivního snížení objemu emisí a souvisejícího zvyšování jakosti vody v tocích. Pozitivní změny v látkové bilanci jsou však soustředěny především na největší toky – Labe a Vltavu a nejsou doprovázeny obdobným vývojem v celém povodí. Pomocí nově vytvořené metodiky klasifikace vývoje kvality vody prezentované v článku byly na základě geostatistické analýzy sestaveny základní modely časové dynamiky změn kvality vody v povodí Labe. Pro jednotlivé ukazatele byly na základě analýzy v prostředí GIS vymezeny regiony s analogickými trendy vývoje kvality povrchových vod a identifikovány kritické oblasti. Ukazuje se, že přes pozitivní vývoj jakosti vody v hlavních sídelních a průmyslových regionech v 90. letech převažující část povodí Labe stále zaznamenává v jednotlivých ukazatelích postupný nárůst znečištění, na řadě toků navíc po předchozím poklesu dochází k opětovnému nárůstu zátěže. Tyto oblasti představují prioritu pro další rozvoj a řízení ochrany povrchových vod před znečištěním.
Estimation of discharge from ungauged catchments based on rainfall-runoff analysis is a very frequent task in engineering hydrology. Very often, design discharges are needed for streams or small rivers where no streamflow data is available (river training works, culverts, small hydropower plants, etc). This study uses a well established lumped hydrologic rainfall-runoff model to compare two different approaches in data preparation. The traditional method of manual obtainment of catchment parameters was compared to a more contemporary methodology using automation with geographic information systems, digital terrain models and available datasets, with an emphasis on open-source tools and freely available datasets. Both techniques were implemented on more than 100 catchments in Serbia to calculate storm runoff response. The results show minor differences that are insignificant compared to the time and resources saved with the automated techniques. The use of such automated methods enables the hydrologist to direct more attention to other factors that influence discharge even more than catchment parameters, such as rainfall, soil and land use data.
Předkládaný článek se soustředí na klíčové období výstavby vodních infrastruktur v Československu, kterým jsou bezpochyby padesátá léta minulého století. Tehdejší masivní výstavba víceúčelových vodních děl, zejména přehradních nádrží a elektráren, ale i vodovodů, probíhající v kontextu socialistické industrializace, položila základy stávajícího státního vodohospodářského systému. V jejím čele stála skupina vodohospodářských odborníků (takzvaných hydrokratů), která se formovala již od dvacátých let. Tito experti zastávali ideály modernistické vodohospodářské mise, směřující k racionalizaci a depolitizaci hospodaření s vodou a spatřující v plném ovládnutí povrchového odtoku základní předpoklad budoucí prosperity státu i obyvatelstva. Období stalinismu podle autora přineslo ideální podmínky k naplnění těchto vizí (zestátnění vodních staveb a zdrojů, centralizace správy i investiční činnosti, ideje přeměny přírody), zároveň byl ale tradiční hydrokratický projekt kompromitován produktivistickými imperativy, což nakonec vedlo k opuštění holistických idejí vyjádřených ve Státním vodohospodářském plánu na roky 1949 až 1953 a jednoznačné soustředění na akumulaci vody pro potřeby průmyslu a energetiky. Od roku 1956 pak v reakci na rostoucí znečištění životního prostředí vznikaly tlaky směřující k přehodnocení stávající vodohospodářské politiky, což v důsledku znamenalo také postupnou korozi idejí vodohospodářské mise., The article focuses on the unquestionably most important period of construction of hydraulic infrastructures in Czechoslovakia, i.e. the 1950s. The massive construction of multi-purpose hydraulic structures, in particular dams and power plants, but also water mains, which was at that time taking place in the context of socialist industrialization, laid the foudnations of the existing national water management system. It was led by a group of water management experts, so-called hydrocrats, which had been forming up since the 1920s. These experts were advocates of ideas of a modernistic water management mission aiming to rationalize and depoliticize water managementand seeing full control of surface runoff as an essential prerequisite of the future prosperity of the state and its population. According to the author, the era of Stalinism brought ideal conditions for the fulfillment of these visions (nationalization of hydraulic structures and water resources, centralization of administration and investment activities, nature transformation ideas); at the same time, however, the traditional hydrocratic project was compromised by imperatives of productivism, which fact ultimately led to the abandonment of holistic ideas formulated in the 1949-1953 National Water Management Plan and a definite concentration on accumulation of water to satisfy needs of the industry and power engineering. Since 1956, there were pressures reacting to increasing environmental pollution levels and calling for a reassessment of the existing water management policy; as a consequence, the ideas of the water management mission were gradually corroding as well., Jiří Janáč., and Obsahuje bibliografii a bibliografické odkazy
The GRACE satellites have provided gravity field solutions with approximately monthly resolution since April 2002. The monthly solutions enable investigations of the annual, semi-annual and secular mass variations, which mainly occur in a thin layer of the Earth’s surface. By the end of the GRACE science mission in 2017, the time span has increased to 15 years, making the possibility of determining longer-period variations feasible. First attempts to determine multi-annual variations, i.e. periods of some years but less than 10, are presented in this study. A combination of 3 different PSD estimation methods has been used for identifying the regions of multi-annual mass variations. As a result, 8 different areas have been found with significant multi-annual mass variations. The source of multi-annual mass variations in most detected regions can be identified as related to the ENSO cycle. and Kiss Annamária, Földváry Lóránt.
The recently published new British Flood Estimation Handbook (FEH) is a unique hydrological publication, giving guidance on rainfall and river flood frequency estimation in the United Kingdom. The FEH is an outcome of a five-year research programme at the Centre of Ecology and Hydrology in Wallingford. The FEH provides novel statistical and geostatistical methods and new hydrological approaches used for assessing the rarity of extreme rainfall and flood events. The publication is accompanied by software (WINFAP-FEH) and digital data (FLOOD DATA CD-ROM). The procedures are clearly explained, and supporting theory and examples are included. The FEH clearly deserves the attention of hydrologists around the world. The main objective of this review is to provide our hydrological community with a brief description of the major methodological approaches used in FEH for rainfall and flood frequency analysis. and Nedávno publikovaný nový britský Flood Estimation Handbook predstavuje vo svete jedinečnú hydrologicků príručku podávajúcu ucelený návod - smernicu pre odhad návrhových zrážok a prietokov vo Veľkej Briránii. Toto dielo je výsledkom päťročnej intenzívnej práce tímu odborníkov z Institute of Hydrology vo Wallingforde. Do príručky sú implementované najnovšie metódy matematickej štatistiky a geoštatistiky. Autori v nej tvorivo inovujú a dopĺňajú hlavné metodické postupy používané momentálně vo svete pri odhade N-ročných srážok a prietokov. Celý projekt má aj softverovú podobu. Príručka si zasluhuje oprávnenú pozornosť hydrológov a klimatológov, a preto hlavným cieľom tohto článku je aspoň veľmi stručne oboznámiť našu odbornú verejnosť s týmto významným dielom a priblížiť jej najvýznamnejšie metodické postupy analýzy extrémnych zrážok a prietokov.