Wyniki wyszukiwania - Biblioteka Nauki

1

Derivation of the SCS-CN parameter S from linearized Fokker-Planck equation

100%

Mishra S. , Singh V.

Acta Geophysica Polonica

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2003

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tom Vol. 51, nr 2

179-202

EN

The potential maximum retention, S, of the Soil Conservation Service Curve Number (SCS-CN) method (SCS, 1956) was derived for a large set of published infiltration data ranging from Plainfield sand to Yololight clay using the relations between psi (negative pressure) and theta (moisture content) and between K (hydraulic conductivity) and theta. The physical significance of S is explained using the diffusion term of the linearized, Fokker-Planck equation for infiltration, which relates S to the storage and transmission properties of the soil. The s-values exhibit a strong looped relationship with the initial moisture content, analogous to that for curve numbers for three antecedent moisture conditions. The variations of S in vertical infiltration is also explained and discussed.

2

SCS-CN method. Part II: Analytical treatment

75%

Mishra S. , Singh V.

Acta Geophysica Polonica

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2003

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tom Vol. 51, nr 1

107-123

EN

This part of the paper, a sequel to Part I, in continuation of the analytical treatment of the Soil Conservation Service curve number (SCS-CN) method, further explores the SCS-CN method for: Z(a) its functional behaviour, (b) the physical interpretation of its proportional equality and curve number, (c) the derivation of seldom explored potential macimum retention S-CN relation, and (d) the development of CN-antecedent moisture condition (AMC) relations. Finally, an attempt is made to present the SCS-CN concept as a viable alternative to power law.

3

Application of Soil Conservation Service Curve Number Method for Runo Estimation in Sebou Watershed, Morocco

75%

Jabri B. , Hessane M. A. , Morabbi A. , Msatef K.

Ecological Engineering & Environmental Technology

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2022

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tom Vol. 23, iss. 6

70--81

EN

In Morocco, although it is often classified as a country with a semi-arid climate, floods are very frequent. Like other basins in the kingdom, the Sebou basin with a total area of 40 000 km² has experienced more catastrophic flooding in the past and these floods have caused enormous economic and even human losses. The objective of this study is to apply different methods to calculate a Curve Number values to estimate the potential runoff for this basin. The techniques used are boils down to the different steps. Firstly, the approach was to extract automatically the sub-basins and drainage network, using Geographical Information Systems (GIS) and Digital Elevation Model (DEM) to determine all the physical characteristics of the basin. Then, preparing the land use map using remote sensing and the soil map for determining hydrologic soil Group. Thirdly, the combination of elaborated data for development of a map of Curve Number (CN) and finally, the interpolation of precipitation data recorded at rainfall stations at 30 minutes time steps to the Hydrologic Modeling System (HEC-HMS) model. The results obtained in the above steps are used for the purpose to get a spatial hydrological model and subsequently its calibration.

4

SCS-CN method. Part 1: Derivation of SCS-CN -based models

75%

Mishra S. , Singh V.

Acta Geophysica Polonica

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2002

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tom Vol. 50, nr 3

457-477

EN

This part of the paper, in a sequence of two, provides an analytical treatment of the Soil Conservation Service Curve Number (SCS-CN) method including its derivation from a) early rainfall-runoff methods, such as the Mockus and Zoch methods, using the Horton method and b) first (linear)- and second (non-linear) -order hypotheses. After a critical review of the available analytical derivations, SCS-CN-based models are proposed for depression, interception storage, and initial abstraction, which forn parts of the SCS-CN method. The performance of the existing and modified versions of the SCS-CN method is evaluated using field data.

5

Flood Peak Discharge vs. Various CN and Rain Duration in a Small Catchment

63%

Banasik K. , Hejduk L. , Woodward D. E. , Banasik J.

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tom Tom 18, cz. 1

201--212

EN

Estimations of flood peak discharges of low probability of exceedance are required for designing and maintaining hydraulic and road structures (reservoirs, weirs, water intakes, bridges, culverts) as well as for flood protection, including assessment of the risk of flooding. Rainfall-runoff models are usually the only alternative for such estimations in case of small catchments as there is a lack of sufficient, good quality historic data to be used for applying the traditional i.e. statistical methods. The aim of this study was to check responses of a small agro-forested catchment to rainfall of assumed 1% probability of exceedance and of various duration, and with various potential of the catchment to form runoff, characterize by a changeable Curve Number – CN. Field data of rainfall-runoff events, recorded in the investigated catchment of Zagożdżonka river since 1980, were used to estimate the model parameters. Application of the rainfall-runoff procedure indicated high sensitivity of peak discharge to CN value. A change in CN of the value of standard error of estimation made ca. 6% change in flood flow

PL

Przepływy maksymalne o niskim prawdopodobieństwie przewyższenia są potrzebne przy projektowaniu i utrzymaniu budowli wodnych i komunikacyjnych (jazy, zbiorniki, ujęcia wód, mosty, przepusty) oraz w ochronie przed powodziami, w tym również przy tworzeniu map ryzyka powodziowego. W przypadku małych zlewni, zwykle nie posiadających pomiarów hydrometrycznych, podstawowym sposobem wyznaczenia takich przepływów jest zastosowanie modeli opad odpływ. Celem pracy było sprawdzenie reakcji małej, rolniczo-leśnej zlewni nizinnej w postaci hydrogramu odpływu bezpośredniego, na ulewne deszcze o przyjętym 1-procentowym prawdopodobieństwie przewyższenia i różnym czasie trwania, oraz przy różnym potencjale formowania się odpływu bezpośredniego w zlewni, charakteryzowanego parametrem CN. Parametry modelu przyjęto na podstawie wieloletnich badań hydrologicznych przeprowadzonych w badanej zlewni. Parametr CN uzależniono od wysokości opadu i dodatkowo wzięto pod uwagę wpływ niepewności w ustaleniu jego wartości na wynik obliczeń. Parametry chwilowego hydrogramu jednostkowego przyjęto jako stałe we wszystkich scenariuszach obliczeniowych. Przedstawiony w wynikach obliczeń – początkowy wzrost przepływów kulminacyjnych hydrogramów odpływu bezpośredniego, a następnie spadek, wraz ze wzrostem przyjmowanych czasów trwania opadów jest efektem równoczesnego oddziaływania wzrastającej objętości odpływu, z danego opadu i zmniejszającego się natężenia średniego. Wyniki analizy wskazują na wysoką wrażliwość przepływów kulminacyjnych na zmianę parametru CN (zmiana CN o wartość standardowego błędu oceny wywołuję ok. 6% zmianę przepływu kulminacyjnego).

6

Beht Watershed (Morocco) Rainfall-Runoff Simulation with the HEC-HMS Hydrological Model

63%

Daide F. , Afgane R. , Lahrach A. , Chaouni A.-A.

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tom Vol. 23, iss. 1

142--155

EN

This research aimed to prepare for spatial hydrological modeling using the Hydrologic Modeling System (HECHMS) by integrating different spatial technologies to study the Beht catchment area, which covers 4560 km2 and also has a perimeter of 414 km. Firstly, the approach was to extract automatically the sub-basins and the drainage network. Then, these data were edited using the HEC-GEO-HMS extension, whereas the land use and land cover data were prepared for the generation of a Curve Number (CN) map of Beht watershed; lastly, the basin model was imported into the Hydrologic Modeling System (HEC-HMS) to simulate the surface runoff. The findings indicated a good match between the calculated and measured values and revealed also that the model is valid, good and performed well in terms of assessment criterion, with average values of Relative Error in peak: REP = 9.6%, Relative Error in volume: REV = 1.69%, Nash-Sutcliffe Efficiency: NSE = 0.63, coefficient of determination: R2 = 0.870, and Ratio of standard deviation of observations to root mean square error: RSR = 0.36.

7

Development of a new method for estimating SCS curve number using TOPMODEL concept of wetness index (case study: Kasilian and Jong watersheds, Iran)

51%

Azizian A. , Shokoohi A.

Acta Geophysica

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2019

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tom Vol. 67, no. 4

1163--1177

EN

In recent years, several empirical and mathematical methods have been developed to estimate runof, among which the SCS curve number (SCS-CN) method is one of the simplest and most widely used methods. The SCS-CN depends mainly on a CN parameter which corresponds to various soil, land cover, and land management conditions, selected from look-up tables. An application of GIS and RS techniques along with fled investigations made it possible to enhance the method from a lumped one to the level of semi-distributed models in which a specifc value can be assigned to each cell in raster maps. The up-to-date procedures require several datasets, feld measurements and overlying issues which limits the use of SCS-CN in data-scarce regions. In this research a new method has been developed which estimates the SCS-CN over the catchment with a minimum input dataset and acceptable accuracy and is based on the saturation-excess concept, which is used in the semi-distributed model: TOPMODEL. The proposed method depends on three parameters, including ndrain (soil porosity), z̄ (average distance to watershed water table surface) and m (which controls the efective depth of the saturated soil) and one input dataset, the so-called topographic index. Results showed that the maximum and minimum diferences between the basin-averaged CN based on the GIS and RS techniques and the proposed method for Kasilian and Jong watersheds are 12% and 0.3%, respectively. Also, the fndings indicated that, of the three parameters of proposed method, the m parameter plays a key role and that by increasing this parameter the basin-averaged CN tends to decrease and vice versa. Because of the dependence on a topographic index, the proposed method is strongly afected by DEM resolution and there are signifcant diferences between low and high-resolution DEMs. However, for a small scale watershed, similar to Kasilian, using DEMs with resolution lower than 100 m considerably decreases the above diferences. As an overall conclusion, the proposed method provides acceptable values of SCS-CN which is important for running rainfall-runof model in a data-limited or data-scarce regions. In addition, creating the gridded map for CN, which is required in most hydrological models, is one of the most important advantages of the proposed method.