Wyniki wyszukiwania - Biblioteka Nauki

1

The use of asymptotic functions for determining empirical values of CN parameter in selected catchments of variable land cover

100%

Wałęga A. , Młyński D. , Wachulec K.

Studia Geotechnica et Mechanica

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2017

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tom Vol. 39, nr 4

111--120

EN

The aim of the study was to assess the applicability of asymptotic functions for determining the value of CN parameter as a function of precipitation depth in mountain and upland catchments. The analyses were carried out in two catchments: the Rudawa, left tributary of the Vistula, and the Kamienica, right tributary of the Dunajec. The input material included data on precipitation and flows for a multi-year period 1980-2012, obtained from IMGW PIB in Warsaw. Two models were used to determine empirical values of CNobs parameter as a function of precipitation depth: standard Hawkins model and 2-CN model allowing for a heterogeneous nature of a catchment area. The study analyses confirmed that asymptotic functions properly described P-CNobs relationship for the entire range of precipitation variability. In the case of high rainfalls, CNobs remained above or below the commonly accepted average antecedent moisture conditions AMCII. The study calculations indicated that the runoff amount calculated according to the original SCS-CN method might be underestimated, and this could adversely affect the values of design flows required for the design of hydraulic engineering projects. In catchments with heterogeneous land cover, the results of CNobs were more accurate when 2-CN model was used instead of the standard Hawkins model. 2-CN model is more precise in accounting for differences in runoff formation depending on retention capacity of the substrate. It was also demonstrated that the commonly accepted initial abstraction coefficient λ = 0.20 yielded too big initial loss of precipitation in the analyzed catchments and, therefore, the computed direct runoff was underestimated. The best results were obtained for λ = 0.05.

2

Using support vector regression to predict direct runoff, base flow and total flow in a mountainous watershed with limited data in Uttaranchal, India

75%

Adamowski J.

Annals of Warsaw University of Life Sciences - SGGW. Land Reclamation

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2013

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tom 45

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nr 1

EN

In the ecologically sensitive Himalayan region, land transformations and utilization of natural resources have modified water flow patterns. To ascertain future sustainable water supply it is necessary to predict water flow from the watersheds as affected by rainfall and morphological parameters. Although such predictions may be made using available process-based models, in mountainous and hilly areas it is extremely difficult to determine the numerous parameters needed to run such models, thus limiting their applicability. Artificial intelligence (AI) based models are a possible alternative in such circumstances. In this study an AI technique, support vector machines (SVM), was used for modeling the rainfall-runoff relationship from three hilly watersheds in the state of Uttaranchal, India. Different SVM models were developed to predict direct runoff, base flow, and total flow based on the daily rainfall, runoff, and morphological parameters collected from each watershed. The results confirm the potential of SVM models in the prediction of runoff, base flow, and total flow in hilly areas.

PL

Na obszarach wrażliwych, jakim są Himalaje, zmiany w wykorzystaniu powierzchni obszarów górskich oraz zasobów przyrodniczych modyfikują warunki kształtowania się odpływu. Dla zrównoważonego gospodarowania zasobami wodnymi w tym regionie koniecznym jest prognozowanie odpływu ze zlewni na podstawie opadu i warunków morfologicznych obszaru. Prognozowanie odpływu przy wykorzystaniu modeli deterministycznych jest dosyć trudne i ograniczone ze względu na trudności w identyfi kacji wielu parametrów. W pracy zastosowano modele wykorzystujące techniki sztucznej inteligencji (AI) za pomocą wektorów wspierających (SVM) jako alternatywę do modelowania zależności opadodpływ dla trzech zlewni górskich w stanie Uttaranchal, Indie. Wyniki zawarte w pracy potwierdzają możliwość wykorzystanie metody SVM do prognozowania charakterystycznych wielkości odpływu w warunkach górskich.

3

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.

4

Direct runoff assessment using modified SME method in catchments in the Upper Vistula River Basin

63%

Wałęga A. , Rutkowska A. , Grzebinoga M.

Acta Geophysica

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2017

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tom Vol. 65, no. 2

363--375

EN

Correct determination of direct runoff is crucial for proper and safe dimensioning of hydroengineering structures. It is commonly assessed using SCS-CN method developed in the United States. However, due to deficiencies of this method, many improvements and modifications have been proposed. In this paper, a modified Sahu–Mishra–Eldo (SME) method was introduced and tested for three catchments located in the upper Vistula basin. Modification of SME method involved a determination of maximum potential retention S based on CN parameter derived from SCS-CN method. The modified SME method yielded direct runoff values very similar to those observed in the investigated catchments. Moreover, it generated significantly smaller errors in the direct runoff estimation as compared with SCS-CN and SME methods in the analyzed catchments. This approach may be used for estimating the runoff in uncontrolled catchments.

5

Usefulness of the Modified NRCS-CN Method for the Assessment of Direct Runoff in a Mountain Catchment

51%

Wałęga A. , Rutkowska A.

Acta Geophysica

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2015

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tom Vol. 63, no. 5

1423--1446

EN

The aim of this study was to evaluate the usefulness of modified methods, developed on the basis of NRCS-CN method, in determining the size of an effective rainfall (direct runoff). The analyses were performed for the mountain catchment of the Kamienica river, right-hand tributary of the Dunajec. The amount of direct runoff was calculated using the following methods: (1) Original NRCS-CN model, (2) Mishra- Singh model (MS model), (3) Sahu-Mishra-Eldho model (SME model), (4) Sahu 1-p model, (5) Sahu 3-p model, and (6) Q_base model. The study results indicated that the amount of direct runoff, determined on the basis of the original NRCS-CN method, may differ significantly from the actually observed values. The best results were achieved when the direct runoff was determined using the SME and Sahu 3-p model.

6

Analiza wpływu wielkości uszczelnienia terenu na hydrogram odpływu ze zlewni

38%

Kolodziejczyk K.

Acta Scientiarum Polonorum. Formatio Circumiectus

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2016

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tom 15

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nr 4