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1

Morphometric analysis of Klina River basin using geospatial technology and open access datasets

Çadraku Hazir, Hasa Xhesika

Journal of Water and Land Development

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2023

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no. 58

31--41

EN

According to the Water Framework Directive 2000/60 EC, the river basin is the basic unit for integrated water management at the basin level. In this sense, the knowledge of the morphometric parameters of the river takes on special importance. Morphometric analysis helps in understanding the geo-hydrological characteristics of a river basin. Various authors point out that the morphometric analyses of a drainage watershed demonstrate the dynamic equilibrium that has been achieved due to the interaction between matter and energy. The analysis of morphometric parameters also facilitates and helps to understand the hydrological relations of the basin. This paper deals with the morphometric analysis of sub-basins in the Klina River basin which is located in the northeastern part of the Dukagjini depression. To determine the morphometric parameters in the Klina River basin, the digital relief model from the Advanced Land Observation Satellite (ALOS) platform with a resolution of 20 × 20 m and the ArcMap 10.5 software were used. The results reveal that the total number of streams is 753 of which 602 are 1st order streams, 119 - 2nd order, 23 - 3rd order, 6 - 4th order, 2 - 5th order, and 1 - 6th order streams. The mean bifurcation ratio is 3.81, drainage density is 1.52 km∙km-2. The data and information presented in this study will be helpful and interesting in the plan of the management of Klina River basin which covers an area of 477 km2 within which is estimated to live about 100,000 inhabitants.

2

Modelling Runoff and Sedimentation Yield Using Soil and Water Assessment Tool for Wyra River Basin

Pindi Shyamsunder, Jayakumar K. V.

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 5

84--93

EN

Sediment deposition is a natural process that occurs in all reservoirs, resulting in significant storage loss, which has an adverse effect on the economic development of the local area. It is necessary to take appropriate action to control the sedimentation and prevent loss of the storage capacity of the reservoir. In the present study, runoff and sediment data collected at the Konijerla hydrometric station of Wyra reservoir for the period of 1991 to 2019 are used. Data from 2011 to 2016 is used to calibrate and the data from 2017 to 2019 is used to validate the SWAT model. The Wyra watershed consists of 26 sub-basins and 47 HRUs (Hydrological Response Units). Out of these sub-basins, one of the sub-basins is contributing 18.8% of sedimentation. It was also observed that two other sub-basins, though less in area, generate high sediments. Seasonal sediment analysis showed that sedimentation increased by 12% in the month of August for wet years. Overall sedimentation increased in wet years by 10.60% and in dry years, it decreased by 18.78%. The SWAT model was satisfactory in the calibration and validation periods for various parameters used. Hence, this model can be used for sedimentation study, as well as a planning tool in the reservoir capacity management.

3

Soil erosion prediction and risk assessment using RUSLE model and GIS techniques in the Nangka watershed

Saadi Yusron, Mardiana Sus, Pradjoko Eko

Journal of Water and Land Development

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2022

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no. 55

185--191

EN

Soil erosion in the Nangka watershed has always been a matter of concern. Over the last decade, soil erosion has led to continuous environmental problems. A thorough examination of the extent of the problem was required to identify an appropriate soil conservation strategy within the watershed. This study was conducted to observe erosion rates and map out the erosion hazard level. Erosion predictions were analysed by using the Revised Universal Soil Loss Equation (RUSLE) model with the help of ArcGIS software. RUSLE was selected because of its quantitative ability to estimate average annual soil erosion and its compatibility with the GIS interface. The potential hazard of soil erosion was classified and ranked into five class categories as set by the national authority. The results reveal that the Nangka watershed is prone to soil erosion with the annual average values ranging from 1.33 Mg·ha-1·y-1 to 2472.29 Mg·ha-1·y-1. High soil erosion rates of 9.8% are in severe (class IV) and very severe (class V) conditions, primarily in the upper course of the watershed. The low annual average of soil erosion (class I and class II), which accounted for 75.95% of the total erosion, mostly took place in the steepness below 35%. The remaining area of 14.25% within the watershed is in moderate condition (class III). It is expected that the results of this study will help the authority in the implementation of soil conservation measures.

4

Regionalisation of watersheds with respect to low flow

Cupak Agnieszka, Michalec Bogusław

Journal of Water and Land Development

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2022

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no. 55

47--55

EN

The aim of the study was to compare two grouping methods for regionalisation of watersheds, which are similar in respect of low flow and chosen catchments parameters (physiographic and meteorological). In the study, a residual pattern approach and cluster analysis, i.e. Ward’s method, were used. The analysis was conducted for specific low flow discharge q95 (dm3∙s-1∙km-2). In the analysis, 50 catchments, located in the area of the upper and central Vistula River basin, were taken. Daily flows used in the study were monitored from 1976 to 2016. Based on the residual pattern approach (RPA) method, the analysed catchments were classified into two groups, while using the cluster analysis method (Ward’s method) - into five. The predictive performance of the complete regional regression model checked by cross-validation R2cv was 47% and RMSEcv= 0.69 dm3∙s-1∙km-2. The cross validation procedure for the cluster analysis gives a predictive performance equal to 33% and RMSEcv= 0.81 dm3∙s-1∙km-2. Comparing both methods, based on the cross-validated coefficient of determination (R2cv), it was found that the residual pattern approach had a better fit between predicted and observed values. The analysis also showed, that in case of both methods, an overestimation of specific low flow discharge q95 was observed. For the cross-validation method and the RPA method, the PBIAS was -10%. A slightly higher value was obtained for the cross-validation method and models obtained using cluster analysis for which the PBIAS was -13.8%.

5

Application of the Erosion Potential Method in Vithkuqi Watersheds (Southeastern Albania)

Marko Oltion, Gjipalaj Joana, Shkodrani Neritan

Journal of Ecological Engineering

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2022

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Vol. 23, nr 4

17--24

EN

Soil erosion is one of the most important phenomena affecting land composition and settlement. Among all natural causes of soil erosion such as rainfall intensity, temperature and wind, the human activity; massive deforestation and intensive agriculture, including the latest climate changes are considered as very important factors, especially nowadays. Thus, calculating the soil erosion coefficient appears very important in order to prevent the phenomena. Many methods are used to calculate such coefficient but in the presented research, the Erosion Potential Method was chosen. In this study, eight watersheds in southeastern Albania were evaluated. Results show that erosion is present in all considered watersheds. In one case (Panariti watershed) the erosion coefficient was very high; excessive, while in others it varies from heavy to very slight erosion. In conclusion, it can be stated that the Erosion Potential Method can be applied in the Albanian contest, same as in other neighbor countries. The results from Panariti, Roshani and Gianci should be further investigated due to the high quantity of soil eroded.

6

Digital Elevation Model-Derived Morphometric Indices for Physical Characterization of the Issen Basin (Western High Atlas of Morocco)

Ait Haddou Mohamed, Wanaim Abderrahmane, Ikirri Mustapha, Aydda Ali, Bouchriti Youssef, Abioui Mohamed, Kabbachi Belkacem

Ecological Engineering & Environmental Technology

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2022

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Vol. 23, iss. 5

285--298

EN

This study attempts to describe the physical characteristics of the Issen basin (western High Atlas of Morocco) in order to highlight the factors affecting water flow and volume that may increase water erosion risk. By using ALOS-DEM of moderate spatial resolution (12.5 m) and GIS platform, it was possible to provide a joint set of morphometric indices of the study area. The obtained results reveal that the relief of the study basin is of mountainous symptom indicating its maturity. The contrasting topography (625 m to 3528 m), with a specific unevenness of the order of 612 m, highlights a strong relief. 94% of the watershed area has a slope of over 3%. The mean elongation of the basin is 1.74, with a fairly long water concentration time of about 7.5 hours and an average drainage density of 0.85 km-1. The tectonics, lithology, and external geodynamics characterstics indicate a strongly contrasted morphology characterizing the Issen basin. Overall, these morphometric characteristics can increase the shallow water flows and sediments mobilized by the Issen Wadi, which can increase the soil loss and flooding risks in the basin.

7

Coupling of Space Remote Sensing and GIS for Detection of Areas at Risk of Degradation (Sidi Mohammed Ben Abdellah Dam Case – Morocco)

Abdelhadi Ouakil, Badr Benhichou, Kaoutar Elbelrhiti, Taha Amimi, Jamal Chao, Hicham Elbelrhiti

Ecological Engineering & Environmental Technology

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2022

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Vol. 23, iss. 6

161--172

EN

Sidi Mohamed Ben Abdellah dam watershed is one of the most vulnerable areas of the risk of soil degradation due to its wide exposure, lithological heterogeneity and varying climatic factors. In this sense, the qualitative study of the spatial-temporal evaluation of ground-level occupancy from satellite visualisation data (acquired by the Landsat TM 5 and Landsat TM 8) device derives a land-use map that shows the areas at risk of degradation after the integration of a combination of multiple factors into a GIS geographic information system (climate, terrain, pedology, vegetation cover and human intervention (anti-erosive practice); The results require adaptive vision to better control the phenomenon, to reduce its severity in areas at high risk of soil degradation.

8

Comparing automatic baseflow separation filters on three watersheds in the urbanised area of East Java, Indonesia

Indarto Indarto, Hardiansyah Mujiono, Sujarwo Mohamad Wawan

Journal of Water and Land Development

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2021

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no. 50

130--140

EN

Baseflow is the primary source of water for irrigation and other water needs during prolonged dry periods; accurate and rapid estimation of baseflow is therefore crucial for water resource allocation. This research aims to estimate baseflow contribution during dry periods in three small watersheds in East Java: Surabaya-Perning (114 km2), Lamong-Simoanggrok (235 km2), and Bangsal-Kedunguneng (26 km2). Six recursive digital filters (RDFs) algorithms are explored using a procedure consisting of calibration, validation, evaluation and interpretation. In this study, the period of July to September is considered as the peak of the dry season. Moreover, data for the period 1996 to 2005 is used to calibrate the algorithms. By yearly averaging, values are obtained for the parameters and then used to test performance during the validation period from 2006 to 2015. Statistical analysis, flow duration curves and hydrographs are used to evaluate and compare the performance of each algorithm. The results show that all the filters explored can be applied to estimate baseflow in the region. However, the Lyne–Hollick (with RMSE = 0.022, 0.125, 0.010 and R2 = 0.951, 0.968, 0.712) and exponentially weighted moving average or EWMA (with RMSE = 0.022, 0.124, 0.009 and R2 = 0.957, 0.968, 0.891) for the three sub-watersheds versions give the best performance.

9

Soil Loss Estimation for Conservation Planning in the Dolago Watershed Central Sulawesi, Indonesia

Naharuddin Naharuddin, Malik Adam, Ahyauddin Ahyauddin

Journal of Ecological Engineering

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2021

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Vol. 22, nr 7

242--251

EN

Soil loss assessment in watersheds is useful in developing plans for the protection and conservation of soil and water in a sustainable manner. This study aimed to determine erosion hazard classification and erosion hazard map using Revised Universal Soil Loss Equation (RUSLE) as the basis of a soil and water conservation planning program. The RUSLE model was used to assess soil loss and guide the soil conservation efforts. Annual rainfall data, digital elevation model (DEM), land use map were used to generate the RUSLE parameters, namely rainfall-runoff erosivity factor (R), soil erodibility factor (K), slope length and steepness factor (LS), cover-management factor (C), and support practices factor (P). Erosion hazard is classified into five classes, namely very low, low, medium, high, and very high. On the basis of the results, at the Dolago watershed, very high erosion hazard was found in dryland of 577.95 t/ha/yr. Meanwhile, very low erosion hazard was found in the rice field of 2.22 t/ha/yr. The results help in planning and implementing soil and water conservation, both vegetatively and mechanically, to minimize the damage to watershed ecosystems. Validation and testing of the RUSLE model should be carried out in future studies because this is a strategic step to develop modeling of sediment yields effectively in an effort to mitigate major land damage in watersheds.

10

Modeling the Hydrological Impacts of Vegetation Cover Changes in the Upper Oum Er-Rbia Watershed (Morocco)

Msaddek Mohamed, El Garouani Abdelkader, Kimbowa George

Journal of Ecological Engineering

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2021

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Vol. 22, nr 6

167--180

EN

In Morocco, the mountainous areas are often exposed to bulky and vicious flows of water and sediment. This process is exacerbated by the decrease in vegetation cover and the disruption in rainfall-runoff conditions that frequently cause significant flooding. By exploring the main hydrologic elements of these processes, it is possible to understand the behavior and hydrological response of watersheds and thus plan accordingly. In this study, the authors focused on determining the morphometric characteristics of the upper Oum Er-Rbia River basin (UOERRB by assessing/ evaluating the land use and land cover changes for a period of 32 years (1984-2016). Hydrologic Engineering Center’s Hydrologic Modeling System (HEC-HMS) was applied to simulate four daily hydrological events. The concentration time was 7.7 hours. The four storm events examined to calibrate and validate the simulated outflow at the outlet indicated a good agreement between the hydrographs of the measured and simulated flows, with an average Nash-Sutcliffe efficiency (NSE) value ranging from 0.63 to 0.76. Between 2002 and 2016, an average 6.21 percent increase in vegetation cover of with annual rainfall increasing from 690 to 714.1 mm/year was observed. These results can contribute to a better understanding of the hydrologic processes and better estimation of the return flows and thus guiding management decisions and developments in the UOERRB.

11

Modeling of Continuous and Extreme Hydrological Processes Using Spatially Distributed Models MERCEDES, VICAIR and VISHYR in a Mediterranean Watershed

Aqnouy Mourad, El Messari Jamal Eddine Stitou, Bouadila Abdelmounim, Morabbi Ali, Benaabidate Lahcen, Al-Djazouli Mahamat Ouchar

Ecological Engineering & Environmental Technology

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2021

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Vol. 22, iss. 1

9--23

EN

Hydrological modeling predicts flood discharge and diminishes the danger by minimizing the environmental damages downstream. This study aimed to investigate the application of the ATHYS Models platform for simulating the rainfall-runoff relationship in Oued Laou Watershed (940 km2 ). The study area is characterized by strong storms associated with the highest rainfall in Morocco, as well as renowned for its regular water supply and historical flooding; for these reasons, it is classified as a vulnerable area during a rainfall event. The models of the ATHYS platform have been implemented in continuous time during (2004–2012), and in four hourly rainfall extremes recorded in March 2018 at the Kodiat Khorireen station. The VICAIR model was used to visualize, analyze and spatially adjust the input data in raster format (land use, soil numerical map, slope, and flow direction). The VISHYR model, on the other hand, was used for corrections, calculations, management, and visualization of local hydro-climatic data in the FTS63 format. Under the MERCEDES model, the combination of the Soil Conservation Service (SCS) production function and the Lag and Route (L&R) transfer function has produced satisfactory results for continuous simulation periods and for the extreme scenarios. The modeling of the flow process in the Oued Laou by the ATHYS platform produced a reasonable performance with an average NSE of 0.70, R2 of 0.73, PBIAS of 13% and RMSE of 0.46. The research results reveal that the storage parameters, soil type, land use, and vegetation are the most important factors affecting the sensitivity of the hydrological response in the Oued Laou watershed. Moreover, the results indicate that the MERCEDES model is an appropriate tool for modeling floods and flow volumes associated with specific rain events and could be used by managers and decision-makers as a tool for flood forecasting in Morocco.

12

Spatialization of water erosion using analytic hierarchy process (AHP) method in the high valley of the Medjerda, eastern Algeria

Belloula Moufida, Dridi Hadda, Kalla Mehdi

Journal of Water and Land Development

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2020

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no. 44

19--25

EN

The present study tries to quantify soil losses using Geographic Information Systems (GIS) and analytic hierarchy process (AHP) in the Medjerda watershed (Algerian-Tunisian border). The Analytic Hierarchy Process (AHP) method is used in the quantification of erosion qualitative characteristics, through its weighting. It is used for many problems requiring decision-making. This catchment area is characterized by moderately consistent lithology, irregular rainfall, medium slope and low vegetation cover, which makes it very sensitive to erosion. Therefore we claim to develop a spatialization map of vulnerable areas, based on analytic hierarchy process and GIS that define the combination of specific factors. The integration of the thematic maps of the various factors makes it possible to identify the impact of each factor in the erosion, to classify the sensitive zones, and to quantify the soil losses in the basin. This mapping will be an important tool for land use planning and risk management. From the distribution map of erosive hazards, we have identified four classes of vulnerability, areas with very high to high vulnerability are mainly in the northern part of the watershed (where the relief is very important).

13

Estimation of suspended sediment rate by double correlation method in Mouillah basin, North-West of Algeria

Belarbi Fadila, Boulchelkia Hamid, Remini Boualem

Journal of Water and Land Development

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2020

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no. 46

29--37

EN

The study deals with the assessment of the solid transport in the wadi Mouillah watershed (Tafna, Algeria). Sediment transport is a complex phenomenon. The quantity of sediment transported is very important, and it fills in the reservoirs. The scale is out of proportion in semiarid areas. Algeria is one of the most affected countries by this phenomenon. A simple method, based on average discharges, easy to implement, has been developed for estimating the sediment yield using double correlation method (a first one between liquid discharge – solid concentration and a second one between solid flow – concentration). It is based on hydrometric data (liquid flow, concentrations and sediment discharges) with applications analysis on seasonal and annual scales for data’s of Sidi Belkheir station at the outlet of the wadi Mouillah watershed (North-West of Algeria). The obtained results by the application of this method are very encouraging because of the quite significant correlation coefficients found (≥59% for the first correlation and ≥88% for the second correlation). The water-shed of Mouillah produces between 43 730 and 56 410 Mg·y–1 as suspended sediment load against 48.56∙103 to 53.3∙103 m3·y–1 of liquid intake.

14

Impact of Landslides Induced by the 2018 Palu Earthquake on Flash Flood in Bangga River Basin, Sulawesi, Indonesia

Tunas I. Gede, Tanga Arody, Oktavia Siti Rahmi

Journal of Ecological Engineering

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2020

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Vol. 21, nr 2

190--200

EN

High magnitude flash flood has occurred several times in some areas in Central Sulawesi Province after the 2018 Palu Earthquake, one of them is in the Bangga River, Sigi Regency, Indonesia. It has caused massive impacts such as damaging agricultural and plantation areas and submerging public facilities and infrastructure and even causing fatalities. The flood carries a variety of materials, especially high concentration sediments which are thought to originate from eroded soils due to landslides induced by a 7.5 magnitude earthquake. These materials are eroded and transported by the flow at the upstream watershed due to heavy rainfall. This study intends to investigate the potential of landslides, factors that trigger floods and increased flooding after the earthquake. This research was conducted by investigating the landslides potency based on field surveys and interpretation of the latest satellite imagery, analyzing the characteristics of rainfall as a trigger for flooding, and predicting the flood potency as the primary impact of these two factors. Rainfall-flood transformation was simulated with the HEC-HMS Model, one of the freeware semi-distributed models commonly used in hydrological analysis. The model input is the configuration of river networks generated from the National DEM (DEMNAS), hourly rainfall during floods and other watershed parameters such as land cover, soil types and river slope. The similar simulation was also carried out on the condition of the watershed before the earthquake. Based on the results of the analysis, It can be inferred that flash floods in the Bangga River are mainly caused by heavy rainfall with long duration and landslide areas in the upper watershed triggered by the 2018 Palu Earthquake with an area of approximately 10.8 km2. The greatest depth of rainfall as a trigger for flooding is 30.4 mm with a duration of 8 hours. The results of the study also showed that landslides in the upper watershed could increase the peak flood by 33.33% from 118.56 m3/s to 158.08 m3/s for conditions before and after the earthquake.

15

Hydrological modeling using the SWAT model based on two types of data from the watershed of Beni Haroun dam, Algeria

Kateb Zakaria, Bouchelkia Hamid, Benmansour Abdelhalim, Belarbi Fadila

Journal of Water and Land Development

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2019

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no. 43

76--89

EN

The dam of Beni Haroun is the largest in Algeria, and its transfer structures feed seven provinces (wilayas) in the eastern part of Algeria. Due to its importance in the region, it has now become urgent to study its watershed as well as all the parameters that can influence the water and solid intakes that come into the dam. The Soil and Water Assessment Tool (SWAT) model is used to quantify the water yields and identify the vulnerable spots using two scenarios. The first one uses worldwide data (GlobCover and HWSD), and the second one employs remote sensing and digital soil mapping in order to determine the most suitable data to obtain the best results. The SWAT model can be used to reproduce the hydrological cycle within the watershed. Concerning the first scenario, during the calibration period, R2 was found between 0.45 and 0.69, and the Nash–Sutcliffe efficiency (NSE) coefficient was within the interval from 0.63 to 0.80; in the validation period, R2 lied between 0.47 and 0.59, and the NSE coefficient ranged from 0.58 to 0.64. As for the second scenario, during the calibration period, R2 was between 0.60 and 0.66, and the NSE coefficient was between 0.55 and 0.75; however, during the validation period, R2 was in the interval from 0.56 to 0.70, and the NSE coefficient within the range 0.64–0.70. These findings indicate that the data obtained using remote sensing and digital soil mapping provide a better representation of the watershed and give a better hydrological modelling.

PL

Beni Haroun jest największym zbiornikiem zaporowym Algierii zasilającym w wodę siedem prowincji we wschodniej części kraju. Podjęcie badań jego zlewni oraz wszystkich czynników, które wpływają na dostawę wody i zawiesiny do zbiornika, okazało się pilne ze względu na regionalne znaczenie zbiornika. Model SWAT (Soil and Water Assessment Tool) wykorzystano do ilościowego ujęcia natężenia przepływu wody i identyfikacji wrażliwych elementów systemu z użyciem dwóch scenariuszy. W pierwszym wykorzystano dane światowe, w drugim dane z teledetekcji i cyfrowych map glebowych celem ustalenia najbardziej odpowiednich danych do osiągnięcia najlepszych rezultatów. Model SWAT można użyć do odtworzenia cyklu hydrologicznego na obszarze zlewni. Według pierwszego scenariusza podczas kalibracji R2 wynosił od 0,45 do 0,69, a współczynnik efektywności Nasha–Sutcliffa (NSE) mieścił się w przedziale od 0,63 do 0,80. Podczas walidacji R2 zmieniał się od 0,47 do 0,59, a współczynnik NSE od 0,58 do 0,64. Według drugiego scenariusza podczas kalibracji R2 wynosił od 0,60 do 0,66, a współczynnik NSE od 0,55 do 0,75. Podczas walidacji współczynniki mieściły się odpowiednio w granicach od 0,56 do 0,70 i od 0,64 do 0,70. Wyniki wskazują, że dane pozyskane z teledetekcji i cyfrowych map glebowych stanowią lepszą reprezentację zlewni i umożliwiają usprawnienie modelowania hydrologicznego.

16

The impact of climatic patterns on runoff and irrigation water allocation in an arid watershed of northern Mexico

Cohen I. S., Ibarra M. A. I., Arriaga G. E., Paredes J. C., Valle M. A. V., Bustamante W. O.

Meteorology Hydrology and Water Management. Research and Operational Applications

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2018

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Vol. 6, Iss. 2

59--66

EN

The uncertainty of water availability is the main problem in planning for water resources in watersheds of agricultural drylands. Water availability for different uses depends on the runoff that is generated in the upper portion of the watersheds, where there are higher elevations and lower temperatures. Proximity to the ocean is a main factor that defines rainfall amounts. In this research we linked the effects of El Niño to a regional Standardized Precipitation Index (SPI) and the subsequent impact on runoff production and irrigation water allocation. Findings indicate the cascading impacts of the El Niño on the SPI, the SPI on the runoff discharge to the irrigation reservoir, and the final impact on the planted area within the irrigation district. An optimization procedure was applied to maximizing net income in agriculture under different water availability scenarios. The restrictions to the optimization model were: total available water, crop water demand, and available land. Local criteria for defining the maximum allowable planted area by crop also were taken into account. The analysis with various water availability scenarios demonstrated that with limited amounts of water for irrigation, forage area would be limited, thereby increasing the area of crops with lower water demands. In both scenarios the area of forage maize was reduced from 11300 to 1764 ha. Increasing irrigation water use efficiency may save water for expanding the irrigated area, or for other uses.

17

Regional modelling with flood-duration-frequency approach in the middle Cheliff watershed

Renima M., Remaoun M., Boucefiane A., Sadeuk Ben Abbes A.

Journal of Water and Land Development

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2018

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no. 36

129--141

EN

This study describes a statistical approach of watercourses hydrological regimes in flood, taking into account the latter duration d and return period T. The choice of Middle Cheliff watershed as study area is linked to disasters strong return period in the western region of Algeria. The Midlle Cheliff catchment basin, located in northwest Algeria, has particularly experienced severe floods over the last years. In view of the recurrence of these unusual events, the estimation and the predetermination of floods extreme quantiles are a strategic axis for prevention against floods in this region. The a curves are first of all locally determined, directly from a statistical analysis of flow continuously exceeded during a duration d (QCXd) on different durations from available data of the study region. Then, these curves are compared to those obtained by application of different regional models VFS (Vandenesse, Florac and Soyans) in which two indices of the watershed characteristic flood are taken into account, a descriptive duration of the flood dynamics (D) and the instantaneous maximal annual flow of 10 year return period (QIXA10). The final choice of the model is based on verification of certain criteria, such as: Nash and the root mean squared error (RMSE). The closest regional models to the local ones are Florac’s for low duration and return periods, and Vandenesse’s for large return periods, for different durations. These results could be used to build regional Q-d-F curves on ungauged or partially gauged Algerian basins.

PL

W pracy opisano statystyczne podejście do reżimu hydrologicznego cieków w trakcie powodzi z uwzględnieniem czasu trwania d i okresu powtarzalności T. Wybór zlewni środkowej rzeki Cheliff wiąże się z krótkim okresem powtarzalności katastrof w zachodnich regionach Algierii. Zlewnia środkowej rzeki Cheliff usytuowana w północnozachodniej Algierii doświadczała w ciągu ostatnich lat silnych powodzi. Ze względu na powtarzalność tych ekstremalnych zjawisk ich ocena i przewidywanie mają znaczenie strategiczne dla zapobiegania powodziom w tym regionie. Krzywe a są najpierw oznaczane w skali lokalnej bezpośrednio w wyniku analizy statystycznej przepływu o czasie trwania d(QCXd) w warunkach różnego czasu trwania z wykorzystaniem dostępnych danych z regionu. Następnie krzywe te są porównywane z krzywymi uzyskanymi z zastosowania różnych modeli regionalnych VFS (Vandenesse, Florac i Soyans), w których bierze się pod uwagę dwa wskaźniki: opisowy przebieg dynamiki powodzi (D) i chwilowy maksymalny roczny przepływ o okresie powtarzalności 10 lat (QIXA10). Ostateczny wybór modelu opiera się na weryfikacji pewnych kryteriów, takich jak Nash i pierwiastek ze średniego błędu kwadratowego (RMSE). Modele regionalne najbliższe lokalnym to Florac dla krótkiego czasu trwania i okresu powtarzalności oraz Vandenesse dla długich okresów powtarzalności w warunkach różnego czasu trwania. Wyniki badań mogą być zastosowane do zbudowania regionalnych krzywych Q-d-F dla algierskich zlewni bez lub z częściową siecią punktów wodowskazowych.

18

Quantification and study of monthly variation of suspended sediment loads in Tafna basin – Algeria

Belarbi F., Bouchelkia H., Remini B., Benmansour A.

Journal of Water and Land Development

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2018

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no. 37

29--38

EN

The magnitude of the phenomenon is disproportionate in semi-arid or in temperate climates. Thus Algeria is one of the most affected countries by this phenomenon and its consequences. To enable a rapid response to the request of engineers and managers to quantify sediment transport at the outlet of a watershed, a simple, easy tool to implement was developed. The principle adopted is based on hydrometric data sets from gauging stations with seasonal and annual time steps to define a suitable method for estimating sediment production. The sediment study was conducted by analysing the daily flows. Pierre du Chat station at the outlet of the Tafna basin served as an application. The obtained results are entirely satisfactory because the correlation coefficients of model Qs = f(Q) range between 72 and 95%. This method, once refined can be generalized to all watersheds in northern Algeria.

PL

Rozmiary sedymentacji są nieporównywalne w klimacie półpustynnym i umiarkowanym. Algieria jest jednym z państw dotkniętych tym procesem i jego skutkami. Aby zapewnić szybką reakcję na wymagania inżynierów i zarządców co do ilościowej oceny transportu osadu, na odpływie ze zlewni skonstruowano proste i łatwe w użyciu narzędzie nadające się do wdrożenia. Przyjęte zasady opierają się na zestawie danych hydrometrycznych z posterunków pomiarowych z użyciem sezonowych i rocznych kroków czasowych w celu zdefiniowania odpowiedniej metody do oceny produkcji osadu. Badania prowadzono, analizując dobowe przepływy. Przykładem był posterunek Pierre du Chat zamykający zlewnię Tafna. Uzyskane wyniki są w pełni satysfakcjonujące, ponieważ współczynnik korelacji modelu Qs = f(Q) wynosił od 72 do 95%. Przedstawiona metoda, po udoskonaleniu, może zostać uogólniona na wszystkie zlewnie w północnej Algierii.

19

Possibility of GPS precipitable water vapour for reservoir inflow forecasting

Uang-aree P., Kingpaiboon S.

Journal of Water and Land Development

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2018

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no. 36

161--171

EN

We investigated the possibility of using GPS precipitable water vapour (GPS-PWV) for forecasting reservoir inflow. The correlations between monthly GPS-PWV and the inflow of two reservoirs were examined and the relationship tested, using a group method of data handling (GMDH) type neural network algorithm. The daily and monthly reservoir inflows were directly proportional to daily and monthly GPS-PWV trends. Peak reservoir inflow, however, shifted from the peak averages for GPS-PWV. A strong relationship between GPS-PWV and inflow was confirmed by high R2 values, high coefficients of correlation, and acceptable mean absolute errors (MAE) of both the daily and monthly models. The Ubon Ratana reservoir model had a monthly MAE of 54.19∙106 m3 and a daily MAE of 5.40∙106 m3. By comparison, the Lumpow reservoir model had a monthly MAE of 25.65∙106 m3 and a daily MAE of 2.62∙106 m3. The models using GPS-PWV as input data responded to extreme inflow better than traditional variables such that reservoir inflow could be predicted using GPS-PWV without using actual inflow and rainfall data. GPS-PWV, thus, represents a helpful tool for regional and national water management. Further research including more reservoirs is needed to confirm this preliminary finding.

PL

W pracy przedstawiono wyniki badań możliwości użycia danych GPS o zawartości pary wodnej (GPS- -PWV) do prognozowania dopływu do zbiornika. Analizowano korelacje między miesięczną wartością GPS- -PWV a dopływem do dwóch zbiorników; zależność testowano, stosując algorytm sieci neuronowej, zwany metodą grupowania argumentów (GMDH). Dobowe i miesięczne dopływy do zbiorników były proporcjonalne do dobowych i miesięcznych trendów GPS-PWV. Maksymalny dopływ odbiegał jednak od maksymalnych średnich GPS-PWV. Silna zależność między GPS-PWV a dopływem została potwierdzona dużymi wartościami R2, wysokim współczynnikiem korelacji i akceptowalnym średnim błędem bezwzględnym (MAE) zarówno w modelu dobowym, jak i miesięcznym. W modelu dla zbiornika Ubon Ratana miesięczny błąd bezwzględny wynosił 54,19∙106 m3 a dobowy – 5,40∙106 m3. Dla porównania w modelu dla zbiornika Lumpow wartość miesięczna MAE wynosiła 25,65∙106 m3, a dobowa 2,62∙106 m3. Modele z wykorzystaniem GPS-PWV jako danych wejściowych reagowały lepiej niż tradycyjne zmienne na dopływ ekstremalny i dlatego dopływ do zbiornika można przewidzieć bez znajomości rzeczywistego dopływu i danych opadowych. GPS-PWV jest więc pomocnym narzędziem w regionalnej i narodowej gospodarce wodnej. Potrzebne są dalsze badania obejmujące większą liczbę zbiorników, aby potwierdzić prezentowane wyniki wstępne.

20

Runoff Hydrographs Using Snyder and SCS Synthetic Unit Hydrograph Methods: A Case Study of Selected Rivers in South West Nigeria

Salami A. W., Bilewu S. O., Ibitoye B. A., Ayanshola M. A.

Journal of Ecological Engineering

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2017

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Vol. 18, nr 1

25--34

EN

This paper presents the development of runoff hydrographs for selected rivers in the Ogun-Osun river catchment, south west, Nigeria using Snyder and Soil Conservation Service (SCS) methods of synthetic unit hydrograph to determine the ordinates. The Soil Conservation Service (SCS) curve Number method was used to estimate the excess rainfall from storm of different return periods. The peak runoff hydrographs were determined by convoluting the unit hydrographs ordinates with the excess rainfall and the value of peak flows obtained by both Snyder and SCS methods observed to vary from one river watershed to the other. The peak runoff hydrograph flows obtained based on the unit hydrograph ordinate determined with Snyder method for 20-yr, 50-yr, 100-yr, 200-yr and 500-yr, return period varied from 112.63 m3/s and 13364.30 m3/s, while those based on the SCS method varied from 304.43 m3/s and 6466.84 m3/s for the eight watersheds. However, the percentage difference shows that for values of peak flows obtained with Snyder and SCS methods varies from 13.14% to 63.30%. However, SCS method is recommended to estimate the ordinate required for the development of peak runoff hydrograph in the river watersheds because it utilized additional morphometric parameters such as watershed slope and the curve number (CN) which is a function of the properties of the soil and vegetation cover of the watershed.