Soil and groundwater salinization are major problems for irrigated agriculture in many arid and semiarid areas of the world. Studies addressing such problems require accurate estimation of salt loadings from irrigated areas through the vadose zone to underlying groundwater. We studied Cl- transport in the vadose zone at 45 locations in a field in the San Joaquin Valley, California, through a combination of soil sampling at six depths (0-1.8 m) and numerical modeling using a coupled water flow and solute transport code (Unsatchem). Our purpose was to assess water and salt loadings from the heterogeneous field to groundwater over a two-year period, and to test applicability of the code to the data. Soil sampling in November, 1995, defined the initial water content and the Cl- concentration, and the soil hydraulic properties. Four more sampling periods, ending in November 1997, provided data for evaluating model performance. Cl- distributions in 1997 exhibited a variety of shapes including monotonically increasing or decreasing distributions versus depth, and profiles with maxima or and sigmoidal shapes. The standard modeling approach, based on the Richards equation and the convection-dispersion equation, predicted more Cl- leaching than was observed in the field. Somewhat improved predictions were obtained when the potential transpiration rate was increased by a factor of 1.5. Better leaching predictions were also obtained when the model included separate mobile and immobile water fractions, mostly by improving the profile shapes. Our study shows the importance of accurate descriptions of the lower boundary conditions, spatial variability in the water infiltration rate, and estimation of soil surface evaporation and transpiration rates. and Zasoľovanie pôdy a podzemných vôd sú hlavnými problémami pôdohospodárstva v závlahových podmienkach v mnohých arídnych a semiarídnych oblastiach sveta. Štúdie, ktoré riešia podobné problémy, vyžadujú si presné určenie zaťaženia soľami zo závlah, ktoré prechádzajú nenasýtenou oblasťou pôdy do podzemných vôd. V tejto štúdii sa zaoberáme transportom Cl- v nenasýtenej oblasti pôdy v 45 lokalitách v San Joaquin Valley, California, využívajúc kombináciu odberu vzoriek pôdy v šiestich hĺbkach (0–1.8 m) a numericakým modelovaním s využitím simulačného modelu kombinovaného transportu vody a rozpustených látok (solí) (Unsatchem). Cieľom je určenie priesaku vody a rozpustených látok z heterogénneho poľa do podzemných vôd počas dvojročného obdobia a testovanie použiteľnosti uvedeného modelu vzhľadom k vstupným hodnotám. Zo vzoriek pôdy, odobratých v novembri 1995 bolo určené počiatočné rozdelenie vlhkosti pôdy a koncentrácia Cl- , ako aj hydraulické vlastnosti pôdy. Štyri ďalšie termíny odberov, končiac v novembri 1997, poskytli údaje pre overenie modelu. Rozdelenie Cl- v roku 1997 sa vyznačovalo rozdieľnosťou tvarov, vrátane monotónne klesajúceho alebo stúpajúceho rozdelenia koncentrácií v závislosti na hĺbke, ako aj profilmi s maximom, alebo aj sigmoidálneho tvaru. Štandardný modelový prístup, založený na Richardsovej rovnici a konvektívno-disperznej rovnici, predpovedal viac vyplaveného Clako bolo pozorované v poli. O niečo lepšie výsledky boli dosiahnuté, ak sa potenciálna transpirácia zvýšila 1,5-násobne. Lepšie výsledky v prognóze vyplavovania solí boli dosiahnuté, ak model obsahoval separátne mobilnú a imobilnú vodu, predpovšetkým zlepšením tvarov vertikálnych rozdelení koncentrácií chlóru. V tejto štúdii bolo ukázané, aké je dôležité presné určenie dolných okrajových podmienok, priestorovej variability rýchlosti infiltrácie, ako aj určenie výparu z povrchu pôdy a transpirácie.
The detailed analysis of individual flood event elements, including peak discharge (Q), flood event volume (V), and flood event duration (D), is an important step for improving our understanding of complex hydrological processes. More than 2,500 flood events were defined based on the annual maximum (AM) peak discharge from 50 Slovenian gauging stations with catchment areas of between 10 and 10,000 km2 . After baseflow separation, the stations were clustered into homogeneous groups and the relationships between the flood event elements and several catchment characteristics were assessed. Different types of flood events were characteristic of different groups. The flashiness of the stream is significantly connected with mean annual precipitation and location of the station. The results indicate that some climatic factors like mean annual precipitation and catchment related attributes as for example catchment area have notable influence on the flood event elements. When assessing the dependency between the pairs of flood event elements (Q, V, D), the highest correlation coefficients were obtained for the Q-V pair. The smallest correlations or no correlations were observed between the Q and D variables.
This paper deals with some ways of carrying out an analysis of a flood event using the KINFIL hydrological model on small catchments where both land use and management play a significant role, and where these human activities can influence design discharges. The combination of GIS techniques with the KINFIL model, which is conceived on physically based infiltration approach and on a kinematic wave transformation of direct runoff, provides a tool for analysing historical rainfall-runoff events, for assessing design discharges, and for simulating some hypothetical flood scenarios. KINFIL is a complex model using the correspondence of Curve Number (CN) with soil parameters and the correspondence of kinematic wave transformation with the physiographical parameters of the Všeminka catchment in Eastern Moravia (Czech Republic), which was used in the tests. Two versions of the KINFIL model (KINFIL1, KINFIL2) were implemented. The infiltration part of the model is the same in both versions. KINFIL 1 assumes a more schematic geometrization of the catchment topography, distributing the catchment area to a V-shaped form in which a main channel collects direct runoff from both side planes or segments. This is not fully in accord with the topography of the sub-catchment. KINFIL 2 is a more sophisticated version, where the topography is GIS-organized, taking fully into account the river network and its corresponding sub-catchment division. The latter version is geographically (and also physically) better based, and the results of the simulation of the July 1997 flood waves in the Vseminka experimental catchment fit better with the observed waves. All the topographical and morphological data were analysed and prepared for the KINFIL model (particularly for the KINFIL 2 version), using GIS facilities. Thus the KINFIL 2 version can be applied in future for design discharge assessment when simulating scenarios of various land uses expressing the model parameters. and Příspěvek analyzuje povodňové případy implementace hydrologického modelu KINFIL, používaného na malých povodích, kde hospodárské využití pozemku a antropogenní vlivy hrají podstatnou roli. Záměrem příspevku je informovat o možnostech využití GIS při fragmentaci malých povodí za účelem zpřesnění vstupních dat pro hydrologický model KINFIL. Kombinace GIS a KINFIL, který je fyzikálně založen na teorii infiltrace a transformace přímého odtoku kinematickou vlnou, poskytuje nástroj pro analýzu jak historických srážko-odtokových případů, tak hypotetických scénářových simulací. Model KINFIL využívá dříve odvozených vztahů mezi hodnotami čísel odtokových křivek CN a „koncepčních“ půdních parametrů (nasycené hydraulické vodivosti a sorptivity) spolu s parametry transformace na testovaném povodí Všeminky na východní Morave. Byly testovány dvě modelové verze: KINFIL 1 a KINFIL 2. Infiltrační část modelu je v obou verzích stejná. Verze KINFIL 1 je založena na schematické geometrizaci, kde povodí je V-tvaru a do hlavního toku je sváděn přímý odtok zobou stran z paralelně uspořádaných desek a každá z těchto desek je sériově (kaskádově) členěna podle sklonu svahů. Takto definované desky ale nemusí plně respektovat členění na subpovodí. Naproti tomu nový přístup KINFIL 2, který za účelem fragmentace povodí využívá prostředků GIS, plně respektuje průběh říční sítě povodí a její členění na subpovodí. Základem pro získání požadovaných parametrů modelu KINFIL 2 je digitální model reliéfu terénu (DEM). Tato verze je geograficky lépe založená a výsledky simulovaných průtoků povodně z července 1997 na experimentálním povodí Všeminky se lépe shodují s průtoky měřenými.
The analysis of in situ measurements of velocity distribution in the floodplain of the lowland river has been carried out. The survey area was located on a bypass channel of the Warta River (West of Poland) which is filled with water only in case of flood waves. The floodplain is covered by grassland and reed marsh habitats. The velocity measurements were performed with an acoustic Doppler current profiler (ADCP) in a cross-section with a bed reinforced with concrete slabs. The measured velocities have reflected the differentiated impact of various vegetation types on the loss of water flow energy. The statistical analyses have proven a relationship between the local velocities and the type of plant communities.
This study examines two long-term time series of nitrate-nitrogen concentrations from the River Ouse and Stour situated in the Eastern England. The time series of monthly averages were decomposed into trend, seasonal and cyclical components and residuals to create a simple additive model. Residuals were then modelled by linear time series models represented by models of the ARMA (autoregressive moving average) class and nonlinear time series models with multiple regimes represented by SETAR (self-exciting threshold autoregressive) and MSW (Markov switching) models. The analysis showed that, based on the minimal value of residual sum of squares (RSS) of one-step ahead forecast in both datasets, SETAR and MSW models described the time series better than models ARMA. However, the relative improvement of SETAR models against ARMA models was low ranging between 1% and 4% with the exception of the three-regime model for the River Stour where the improvement was 48.9%. In comparison, the relative improvement of MSW models was between 44.6% and 52.5 for two-regime and from 60.4% to 75% for three-regime models. However, the visual assessment of models plotted against original datasets showed that despite a high value of RSS, some ARMA models could describe the analyzed time series better than AR (autoregressive), MA (moving average) and SETAR models with lower values of RSS. In both datasets MSW models provided a very good visual fit describing most of the extreme values. The results of this work could be used as a base for construction of other time series models used to describe or predict nitratenitrogen concentrations. and Štúdia sa zaoberá analýzou dlhých časových radov koncentrácií dusičnanového dusíka v rieke Ouse a Stour vo Východnom Anglicku. Časové rady priemerných mesačných koncentrácií dusičnanov boli rozložené na trendovú, sezónnu a cyklickú zložku a reziduá pripočítané k sebe a tvoriace jednoduchý aditívny model. Reziduá boli ďalej modelované zložitejšími lineárnymi modelmi reprezentovanými modelmi triedy ARMA a nelineárnymi viacrežimovými modelmi SETAR a MSW. Výsledky analýzy ukázali, že na základe minimálnej hodnoty sumy štvorcov reziduí (SSR) jednokrokovej predpovede, v oboch prípadoch SETAR aj MSW modely opísali časové rady lepšie ako modely triedy ARMA. Vo väčšine prípadov relatívne zlepšenie modelov SETAR oproti jednoduchým AR(1) modelom bolo malé v rozmedzí od 1 do 4 % s výnimkou trojrežimového modelu pre rieku Stour, kde to bolo až 48,9 %. Naopak, relatívne zlepšenie modelov MSW oproti AR(1) modelom bolo v rozmedzí 44,6 až 52,5 % pre dvojrežimové a 60,4 až 75 % pre trojrežimové modely. Vizuálne posúdenie jednotlivých modelov však ukázalo, že napriek vysokým hodnotám SSR, niektoré ARMA modely dokázali lepšie opísať dané časové rady ako modely AR, MA a SETAR s nižšími hodnotami SSR. V oboch prípadoch MSW modely dokázali dostatočne dobre opísať aj extrémne hodnoty oboch časových radov. Výsledky práce môžu byť použité pri tvorbe iných opisných alebo predpovedných modelov koncentrácie dusičnanového dusíka vo vodách.
The paper presents review of occurrence frequency of extreme hydrological events in a small agricultural basin in the flysh region over the period of 40 years (1964/65 - 2003/04). No human alterations were carried out in the basin over the period studied and hence influence of climatic changes on intensification of water cycle could be evaluated. Peaks over threshold (POT) method was applied separately to winter and summer hydrological events. In comparison with annual maximum series, all mean daily discharge values over a certain thresholds were taken into account for POT frequency analysis. The frequency of POT events has decreased in the past two decades (1984/85 - 1993/94 and 1994/95 - 2003/04). The results reveal that the most extreme values occurred in the 1964/65 - 1973/74 decade, mostly caused by summer rainfall. High event frequency also emerges in the 1974/75 - 1983/84 decade, especially in winter seasons as the consequence of snow melting. It is most likely that influence of climatic changes has not resulted yet in increase of occurrence frequency of POT events in the basin studied over the 40 years period. and Príspevok sa zaoberá frekvenciou výskytu extrémnych hydrologických udalostí na malom poľnohospodárskom povodí vo flyšovom pásme počas 40-ročnej periódy (1964/65-2003/04). Počas tohto obdobia nebolo povodie ovplyvnené významnými zmenami ľudskej činnosti a preto mohol byť zhodnotený vplyv klimatických zmien na intenzifikáciu hydrologického cyklu. POT metóda bola aplikovaná zvlášť pre zimné a letné hydrologické udalosti. V porovnaní so sériami ročných maxím, všetky priemerné denné prietoky nad určitou prahovou hodnotou boli zahrnuté do POT frekvenčných analýz. Frekvencia POT udalostí (nad zvolenou prahovou hodnotou) klesla v posledných dvoch dekádach (1984/85-1993/94 a 1994/95- 2003/04). Výsledky ukazujú, že najextrémnejšie hodnoty priemerných denných prietokov, spôsobené prevažne letnými prívalovými zrážkami sa objavili v dekáde 1964/65-1973/74. Vysoké hodnoty prietokov, spôsobené prevažne topením snehovej pokrývky sa vyskytli tiež v dekáde 1974/75-1983/84. Je nanajvýš pravdepodobné, že v študovanom povodí za obdobie 40-tich rokov klimatické zmeny nemali zatiaľ vplyv na zvyšovanie frekvencie extrémnych udalostí.
The paper contains a sensitivity analysis of the influence of uncertainties in input hydrological, morphological and operating data required for a proposal for active reservoir conservation storage capacity and its achieved values. By introducing uncertainties into the considered inputs of the water management analysis of a reservoir, the subsequent analysed reservoir storage capacity is also affected with uncertainties. The values of water outflows from the reservoir and the hydrological reliabilities are affected with uncertainties as well. A simulation model of reservoir behaviour has been compiled with this kind of calculation as stated below. The model allows evaluation of the solution results, taking uncertainties into consideration, in contributing to a reduction in the occurrence of failure or lack of water during reservoir operation in low-water and dry periods.
Time series of the daily total precipitation, daily wastewater discharges and daily concentrations and pollution loads of BOD5, COD, SS, N-NH4, Ntot and Ptot were analyzed at the inflow to the wastewater treatment plant (WWTP) for a larger city in 2004-2009 (WWTP is loaded by pollution from 435,000 equivalent inhabitants). The time series of the outflow from a WWTP was also available for 2007. The time series of daily total precipitation, daily wastewater discharges, concentrations and pollution loads at the inflow and outflow from the WWTP were standardized year by year to exclude a long-term trend, and periodic components with a period of 7 days and 365 days (and potentially also 186.5 days) were excluded from the standardized series. However, these two operations eliminated only a small part of the variance; there was a substantial reduction in the variance only for ammonium nitrogen and total nitrogen at the inflow and outflow from a WWTP. The relationship between the inflow into a WWTP and the outflow from a WWTP for the concentrations and pollution loads was described by simple transfer functions (SISO models) and more complicated transfer functions (MISO models). A simple transfer function (SISO model) was employed to describe the relationship between the daily total precipitation and the wastewater discharge.
In this paper, we deal with sentences containing time references like ''five years ago'', ''three years older'', ''in five seconds''. It turns out that such sentences are pragmatically incomplete, because there is an elliptic reference to a calendar that makes it possible to determine the length of the time interval associated with a time duration like a year, month, day, or to compute the time interval denoted by terms like ''February 29, 2016''. Since Transparent Intensional Logic (TIL) takes into account two modal parameters, namely possible worlds of type ω and times of type τ, and this system is particularly apt for the analysis of natural language expressions, our background theory is TIL. Within this system, we define time intervals, calendar time durations, and last but not least a method for adding and multiplying time durations in a way that takes into account the leap days and leap seconds. As sample applications, we analyse two sentences, to wit, ''A year has 365 days'' and ''Adam is 5 years older than Bill''. and V tomto článku se zabýváme věty obsahujícími časové odkazy jako ''před pěti lety'', ''o tři roky starší'', ''za pět sekund''. Ukazuje se, že takové věty jsou pragmaticky neúplné, protože existuje eliptický odkaz na kalendář, který umožňuje určit délku časového intervalu spojeného s časovým obdobím jako rok, měsíc, den nebo vypočítat časový interval označované slovy ''29. února 2016''. Vzhledem k tomu, že Transparentní Intenzivní Logika (TIL) zohledňuje dva modální parametry, jmenovitě možné světy typu ω a časy typu τ, a tento systém je obzvláště vhodný pro analýzu přirozených jazykových výrazů, je naší teorií pozadí TIL. V rámci tohoto systému definujeme časové intervaly, trvání kalendáře, a v neposlední řadě metoda pro přidání a násobení doby trvání způsobem, který bere v úvahu skokové a skokové sekundy. Jako vzorové aplikace analyzujeme dvě věty s názvem ''rok má 365 dní'' a ''Adam je o 5 let starší než Bill''.
This paper proposes a non-trivial definition of the notion of analytic method. Working within the so-called instructional model of method, I distinguish three kinds of instructions which occur in methods: selective, executive, and declarative instructions. I discuss the relation between each of these and the analyticity of a method. Then I define the notions of an analytic use of an instruction and of an analytic instruction, which are at the basis of the proposed definition of an analytic method. Finally, I discuss the issue of circularity in the presented model which arises if we consider a finite agent testing a method for analyticity., Tato práce navrhuje netriviální definici pojmu analytická metoda. V rámci tzv. Instruktážního modelu metody rozlišuji tři druhy instrukcí, které se vyskytují v metodách: selektivní, exekutivní a deklarativní . Diskutuji o vztahu mezi každou z nich a analytičnosti metody. Dále definuji pojmy analytického použití instrukce a analytické instrukce , které jsou základem navrhované definice analytické metody. Závěrem se zabývám otázkou kruhovitosti v prezentovaném modelu, která vzniká, pokud uvažujeme konečný agent testující metodu analyticity., and Miloš Kosterec