Drainage Frequency Research Articles

Hydrogeomorphic assessment of badlands in part of the Mandakini River watershed, Chitrakoot, India

Badlands are a hydrogeomorphological feature with operative processes leading to intense erosion. This study utilizes the morphometric methods with the help of remote sensing data in a GIS environment to determine the characteristics of the badlands of Mandakini River watershed and their interpretation to explore the factors responsible for the formation of the typical landforms. Objective interpretation of morphometric data of badlands with the help of statistical Pearson’s correlation coefficient (PCC) and dendrogram cluster may be made to emphasize the controlling factors. The morphometric parameters like the total number of streams (Nu), bifurcation ratio (Rb), drainage density (Dd), drainage frequency (Fs), drainage texture (Dt), and infiltration number (If) and their correlation in the study area plays a significant role in the advancement of rills and gullies. In the present area, the total number of streams (Nu) is very significantly related with the lengths of the first-order (L1), the second-order (L2), and the third-order streams (L3) along with the total stream length of all orders (Lu) in the third-order and the fourth-order sub-watersheds. Bifurcation ratio (Rb) is strongly correlated with L1, L2, L3, L4, and drainage texture (Dt) in the fourth-order sub-watershed. These correlations insinuate a tectonic influence in the basin and show an ultrafine drainage texture that ultimately forms badland topography. The relation between Dd-Lg-C-If-Rn produces a self-enhancing system of badland development, which promotes erosion in the area under study. These correlations provide a well-figured observation of the sub-watershed that, due to the increase in infiltration number (If), the drainage density (Dd) also increases, which leads to enhancement of channel cutting and erosion rates (low Lg and C value). This correlation coefficient of Rn is moderately low, indicating a single storey type of badlands. The badlands seem to have formed owing to setting up of self-enhancing erosive system on paleo wetlands, as evidenced by the presence of calcretes. Calcretes have been related to the presence of wetlands’ conditions. These have been related to fall in water levels, therefore, indicating much higher water levels nearly close to ground surfaces before setting up badlands conditions. Thus, the badlands which have shallow calcretes horizons can be said to have been wetlands in the past.

Flood Susceptibility Modeling of Megech River Catchment, Lake Tana Basin, North Western Ethiopia, Using Morphometric Analysis

The present study intended to flood susceptibility modeling by using drainage morphometric investigations of the Megech River catchment, Lake Tana Basin, North Western Ethiopia. Drainage morphometric criterion study performs a critical aspect in recognizing the factual aspects of river catchment with concern to floods. In the present study, we depicted the Megech River catchment into four sub-watersheds, followed by clipping off the drainage grid by using ALOS-PALSAR (Advanced Land Observing Satellite-Phased Array-Type L-Band Synthetic Aperture Radar) digital elevation model, toposheets, and Landsat-8 Operational Land Imager coupled with the Geographic Information System (GIS) program. The drainage morphometric parameters, such as basic, linear, areal and relief, were calculated in the current research by using the standard formula. The morphometric parameters, such as bifurcation ratio, drainage density, length of overland flow and drainage frequency, have a direct connection with flood susceptibility. Hence, rank 1 assigned to the highest values of the above-mentioned parameters followed by second-rank to second-highest value and rank third given the lowest value of the above parameters. The morphometric parameters, such as circulatory ratio, form factor, elongation ratio, drainage texture and compactness coefficient, have a reverse relation with flood proneness. Hence, rank 1 assigned to the lowest values of those parameters, followed by rank two to the second-lowest value and rank three given to the highest value of the above parameters. The compound factor is computed by aggregating the assigned ranks of the morphometric drainage parameters mentioned above and then dividing by the number of morphometric criteria used for sub-watersheds prioritization. The results of the present study displayed sub-watershed 3 scored very high prioritization (Ist), including a compound factor value of 1.89, and sub-watershed 2 got the highest compound factor value of 3.11, and it scored the lowest rank (IVth). The found sub-watershed 3 in the current research area was acquired as a high-priority grade one, and it demands urgent flood regulation remedies for competent water budget devising and administration in the Megech catchment area. The current study demonstrates the capability of sub-watershedwise drainage morphometric investigations in the flood susceptibility analysis using toposheets, optical remote sensing data and digital elevation model associated with GIS tools.

Morphometric analysis of a badland affected portion of the Mandakini River sub-watershed, central India

Morphometric analysis has evolved as an important tool for basin management and to study the process performing in the basin. The trio of remote sensing, GIS, and morphometric analysis gives the best possible results in investigating, supervising, and understanding the basin. The present study comprises a detailed study of morphometric parameters in a badland affected sub-watershed of the Mandakini River. The sub-watershed is located in the northern foot slope of Vindhyan mountain range. The area consists of many structural and denudational hills, pediment, and pediplain complexes. Geologically soft sedimentary rocks are in the majority in this terrain and the area comprises a diverse range of gullies, in terms of shape and size. The intensity of the study is both macro and micro watershed level (up to the third and fourth sub-watershed level). The analysis is mostly based on derived parameters such as bifurcation ratio (Rb), drainage density (Dt), stream frequency (Fs), drainage texture (Dt), length of overland flow (Lg), and constant of channel maintenance (C), shape parameters such as circularity Ratio (Rc), elongation ratio (Re), form factor (Rf), and in relief parameter ruggedness number (Rn) and dissection index (Di). The analysis shows that low infiltration rate, i.e., a higher value of infiltration number (70.0), triggers high runoff and hence increases drainage density (4.5), drainage frequency (15.16), and drainage texture (25.23) and ultimately from an erosional setup in the sub-watershed and it is gradually deforming the land into a rugged terrain.

English

The development of drainage basins to raise aquifer potentiality is considering the major target in Qena-Safaga-Bir Queh (central Eastern Desert). It is attributed to drought, scarce groundwater resource, expansion of agriculture, growth population, infrastructures, and civilization. Geological, hydrogeological, and morphometric information is used to prepare the drainage development plan and strategy. The morphometric parameters were used to evaluate the hydraulic conductivity of the surficial lithology. The aquifer recharge rate was established according to permeability ranking of the surface geology. DEM, ETM+8, geologic map, and SPSS were used to characterize the hydrological parameters and delineate the watershed. Ten drainage basins were extracted and characterize for the morphometric analysis. The digital geological distribution, of each basin, was determined from geological and remote sensing data. The morphometric parameters (drainage density, constant channel maintenance, length of overland flow, drainage frequency, and drainage texture ratio) indicate the basins related to medium surface rock permeability (weight score 7-12). Multivariate statistical techniques were investigated using 17 morphometric descriptors (variables). The dendrogram analysis (R-mode) was divided into two cluster, which was subdivided into four groups. BirQueh basin is independent basin due to highest drainage area and perimeter. There is great hydrological similarity between sub basin 9 and 10 (wadi Qena). Wadi Safaga is hydrologically similar to sub basin 3, followed by sub basin 4. The principle component analysis contains four factors and represented by 74% of the total variance in the data. It identifies the promising areas in local scale, so that development and agriculture are easier. Key words: Drainage basins, morphometric parameters, SPSS, central Eastern desert.

Mapping of soil erosion-prone sub-watersheds through drainage morphometric analysis and weighted sum approach: a case study of the Kulfo River basin, Rift valley, Arba Minch, Southern Ethiopia

In the present study, soil erosion prioritization of sub-watersheds of the Kulfo River basin was conducted by adopting a drainage morphometric analysis along with a statistical correlation matrix-based weighted sum approach. The drainage network extracted and sub-watershed boundaries were demarcated through GIS techniques using advanced space-borne thermal emission and reflection–digital elevation model (ASTER–DEM). The Kulfo River basin was separated into six sub-watersheds (SW-1 to SW-6), and different morphometric criteria were calculated using the standard formula. And, morphometric parameters like drainage frequency, bifurcation ratio, drainage density, form factor, circulatory ratio, drainage texture, elongation ratio, compact coefficient, and length of overland flow have been considered for sub-watershed prioritization. Based on the results, the Kulfo River basin’s sub-watersheds were categorized into five priority classes: very low, low, medium, high, and very high. The results illustrate the sub-watersheds (SW-1, SW-2, SW-3, and SW-6) that approximately 65% of the Kulfo River basin’s total area fall under the very high, high, and medium soil erosion-prone areas, respectively. Therefore, the above-mentioned four sub-watersheds can be a value for the consideration of the soil protection plan. The outcomes derived from this study will be valuable information for several partners like agriculturists, surface and groundwater wealth administrators, and decision-makers for improving the soil management process. The current research shows that ASTER–DEM data, GIS approach, and a statistical correlation matrix-based weighted sum approach are vibrant tools for watershed prioritization in data-scarce regions.

Geomorphic diversity and landslide susceptibility in the Balason River Basin, Darjeeling Himalaya

This study attempts to assess the role of basin morphometric parameters in slope instability using a morphometric diversity (MD) model, as well as the role of drainage parameters and relief parameters in slope failure using drainage diversity (DD) and relief diversity (RD) models, respectively. For this, a total of 14 morphometric data layers were considered. The relationship of each data layer to landslide susceptibility was judged using a frequency ratio (FR) approach. Parameters like drainage density (Dd), drainage frequency (Df), relative relief (Rr), drainage texture (Dt), junction frequency (Jf), infiltration number (In), ruggedness index (Ri), dissection index (Di), elevation (E), slope (S), relief ratio (Rra) and hypsometric integral (Hi) were positively related with landslide potentiality while bifurcation ratio (Rb) and drainage intensity (Din) negatively correlated with S failure. The principal component analysis (PCA)-based weight assigned to each data layer in each model was multiplied with unidirectional reclassified data layers for each model using a weighted linear combination (WLC) approach to prepare landslide susceptibility maps. The receiver operating characteristics curve showed that the landslide prediction accuracy of the DD, RD and MD models were 71.4%, 73.9% and 76.3%, respectively. The FR plots of the aforesaid three models suggested that the chance of landslide increases from very low to very high in susceptible zones.

Estimation of Various Geomorphometric Aspects of Kandra River Basin of Panhala Tehsil, Kolhapur District (M.S.)

The term morphometry senses the measurement and analysis of form and its properties. In context of geomorphology, which is science of land forms, it is concerned with the various geometrical aspects of the landforms. It is inevitable in the study of fluvial geomorphology. Morphometric analysis particularly deals with quantitative measurements of different aspects like linear, aerial and relief, for instance stream order, stream length, drainage density, drainage frequency, bifurcation ratio, constant channel maintenance etc. Kandra River one of the major tributaries of Warana River flows on southern part of Deccan Trap of Maharashtra and occupies an area of about 148sq. km. The stream orders of this basin range from first order to fifth order. The dendritic drainage pattern indicates the homogeneity in texture and lack of structural control on the rocks of the area. The average drainage density of the river is 2.12; however it varies within the basin which detects the minor changes in the terrain configuration and gradient intensity and its aspects. Drainage frequency is also dynamic however, the average drainage frequency is 2.02 which is an outcome of the undulating and rugged terrain supported by the constant of channel maintenance of basin that is 0.47 km2/km. Keywords: Stream orders, Dendritic drainage pattern, Drainage density, Drainage frequency.

An integrated approach of GIS, RUSLE and AHP to model soil erosion in West Kameng watershed, Arunachal Pradesh

Soil erosion has always been a major environmental problem in many parts of the world including the northeastern region of India. An increase in the rate of soil erosion has tremendous implications on land degradation, biodiversity loss, productivity, etc. Hence, assessment of soil erosion hazard and its spatial distribution is essential to serve as a baseline data for effective control measures. The present study uses revised universal soil loss equation (RUSLE) and analytical hierarchy process (AHP) approach integrated with geospatial technology for modeling soil erosion hazard zone of West Kameng watershed of Arunachal Pradesh, Northeast India. The assessment showed that the erodibility factor of soil ranged between 0 and 0.38 t/ha/MJ/mm and slope length and steepness factor increases with increase in slope angle. Lower normalized difference vegetation index (NDVI) values depict vegetation cover and higher values represent the rocky area or barren land. Spatial distribution of conservation support practice on soil loss indicated the variability (0–1) where lower value represents the higher conservation practice. The predicted average soil erosion rate was 124.21 t/ha/Yr. Normalized eigenvector values ranged between 0.03 and 0.20. The areas with more slope, relative relief, drainage density, lineament density, and frequency have shown comparatively higher eigenvector values, and it has been noticed that the strength of these eigenvectors reduces with a decrease in the values of the parameters. The spatial soil erosion potential map was delineated using eight geo-environmental variables (LULC, geomorphology, slope, relative relief, drainage density, drainage frequency, lineament density, and lineament frequency). The soil hazard map showed that the moderate soil erosion has the maximum (57.71%) area cover followed by high erosion class (26.09%) which depicts that most of the watershed areas are moderate to high vulnerable to soil erosion. The efficiency of the AHP was validated applying area under curve (AUC) method which result 84.90% accuracy in the present study. Based on the findings, it is being recommended that present watershed requires adequate control procedures on a priority basis to conserve soil resources and reduce flood events and siltation of water bodies.

Morphometry of drainage basins and stream networks as an indicator of active fold growth (Gorm anticline, Fars Province, Iran)

The Zagros Folded belt, as one of the most tectonically active areas in the world, contains NW–SE trending whaleback anticlines that are growing vertically and laterally. Morphometric indices are widely used in tectonic geomorphological research because of their low cost and relative ease of application. Drainage basins and their networks adapt to tectonically induced changes in surface slope, and hence their qualitative and quantitative analysis can reveal aspects of active anticlinal growth. This study evaluates the morphometric properties of drainage basins and their networks developed on the fold limbs, using this quantitative data to detect lateral propagation of the Gorm anticline in the Zagros Simply Folded Belt (ZSFB). The Gorm anticline was considered to be suitable for this approach because of the variability of drainage basins and their networks along the axis of the anticline and also transversely across its forelimb and backlimb. The morphometric properties of stream networks including drainage density (Dd), drainage frequency (Df), ratio of 1st-order streams to the total number of streams of all orders (N1/N), length of 1st-order streams (L1), spacing ratio (R)of main streams on flanks, and drainage patterns were analyzed in three zones of the anticline (southeastern (SE), central, and northwestern (NW)). Also, the morphometric indices of drainage basins such as basin area (Ba), shape (Bs), asymmetry factor (AF), hypsometric integral (HI), a new proposed crescentness index (CI), and sinuosity of anticline divide (SAD) were evaluated. Results show that an increase in N1/N ratio and L1 from the center towards both the southeastern and northwestern fold noses suggests lateral growth of the anticline towards the southeast and northwest. The SE and NW zones are characterized by the smaller, elongated and crescent-shaped basins, lower elevations, lower dip slopes, higher hypsometric integral, and lower sinuosity of anticline ridge. These results collectively suggest that the southeastern and northwestern fold noses are younger, less eroded and laterally growing. The formation of crescent-shaped basins with asymmetric forked drainages developed in the SE and NW zones are considered to be useful indicators of lateral growth of the Gorm anticline. Although higher values of Ba, SAD, Df and S indexes in the central part of the fold can be attributed to the older relative age of this area, the activity of the Nezamabad Fault and the exposure of some weak rocks also play some roles in explaining the increase the values of parameters. Overall, the N1/N, L1, CI, SAD indexes, as well as the fan-shaped and asymmetric forked drainage pattern are the most useful tectonic geomorphological criteria to detect lateral propagation of anticlines.

Faecal contamination in groundwater and its association with population density: a study in coastal areas of Semarang

Increased population density causes the supply of clean water to be unable to meet the requirements. The coastal area of Semarang is also faced with a tidal problem. While good sanitation is a top priority in improving health, nutrition and productivity (6th SDG target), the cause of water borne disease must be considered. This research was conducted in May 2019 at 30 points in the coastal area of Semarang, covering 9 sub-districts. Assessment of microbiology is carried out on coliform parameters and the presence of Eschericia coli. Data on septic tank type, depth, distance of the septic tank to the sample points and drainage frequency were collected. Population data are based on data from BPS. Hydrogeological mapping was used to describe the distribution of faecal contamination and other factors. Around 73.3% of the groundwater samples exceeded the coliform parameter limit and 86.7% of the samples were found to have E. coli. Only 37.5% of the septic tank is cemented and 66.7% with a safe distance from the water source. Population density was not significantly related to poor groundwater quality, because even though the area is less densely populated, E. coli is found positive in ground water.

Badland Erosion and Its Morphometric Features in the Tropical Monsoon Area

Climatically driven processes are important controls on the Earth’s surface and on interactions between the hydrological cycle and erosion in drainage basins. As a result, landscape forms such as hillslope topography can be used as an archive to reconstruct historical climatic conditions. Recent progress in the Structure-from-Motion (SfM) photogrammetric technique allows for the construction of high-resolution, low-cost topography data using remote-controlled unmanned aerial vehicle (UAV) surveys. Here, we present the climatic effects on the hillslope erosion rate that can be obtained from the drainage frequency of hillslopes. We quantify the centimeter-scale accuracy of surveys across 72 badland hillslopes in SE Taiwan, which is a tropical monsoon area with an annual precipitation of over 2 m. Our observations indicate that climatic erosion results in a higher drainage frequency and the number of furrows, instead of drainage density. Additionally, the morphometric slope index (MSI) has a strong positive correlation with erosion and its rate but shows a negative correlation with drainage length and a positive correlation with inclination. This suggests that the erosion pattern is due to gravitational mass wasting instead of hydrological erosion. MSI should always be calculated relying on the normalized slope length and is less applicable to landslide-dominated erosion. We, therefore, suggest that UAV-driven digital elevation models (DEMs) are integrated into erosion mapping to aid in identifying erosion patterns. We highlight the unique opportunity for cross-climate zone comparative studies offered by badland landscapes and differential rainfall patterns, with remote sensing techniques and the morphometric slope index.

Qurain AL-Thamad Valley Hydrological Aspects Extraction Using Remote Sensing and GIS Techniques

In the arid to semi-arid lands the extracted hydrological features are essential ones, since their effect on water projects managing, agricultural projects administrating, and animals grazing, so that this research is considered to be vital research because the climate of Qurain AL-Thamad basin is arid climate and basin region inhabited by many tribes who works in agricultural and grazing fields. The illustration of hydrological features using morphometric analyses is optimum since the quantization issue of basin factors, in the past this would be difficult using classical procedures (i.e. using paper topographic maps and planmeter). Recently as in this work modern procedures has been used (i.e. satellite imagery DEM as ancillary image and Arc GIS 10.5 as geo-measuring and spatio-analyzing program).
 The pattern of Qurain AL-Thamad basin's drainage network shows dendritic configuration in low orders streams and parallel configuration in the high order streams. The spatial analysis using GIS environment categorize basin's shape parameters into three categories: firstly one is the linear parameters with streams divided into 1st order streams with (611.587 km) length, 2nd order streams with (384.015 km) length, 3rd order streams with (181.868 km) length, and 4th order streams with (103.674 km) length. Bifurcation ratios were calculated, Rb1 is (2.046), Rb2 is (1.869), and Rb3 is (1.624), with (1.852) Rb mean value. Secondly categorize deals with areal parameters; The longitudinal drainage density was (0.259 km??), the drainage frequency was (0.035 stream /km²), Drainage Texture value was (0.338 stream / km ), the elongation ratio was (0.483), the circularity ratio value was (0.244), the form factor was (0.183) , and the relief ratio was (0.447). according to these quantitative results the flood hazard in the basin main stream is absent, basin soil is high permeable and region rainfall rate is very low, there is significant differences in region geological structures solidity, land steepness and relief ratio are low valued yielding a few water erosion power, sediment yield, and runoff flood peak in the basin water catchment area.

Identification of potential sites for runoff water harvesting

Runoff water harvesting (RWH) is a potential solution for areas suffering from water scarcity, such as the western desert of Iraq. Site selection based on RWH ranking using a combination of a watershed modelling system, geographic information systems and remote sensing techniques may enable authorities and water engineers to determine potential solutions to water scarcity. In this work, these methods were employed to produce eight thematic maps of the volume of annual floods, basin area, basin length, maximum flow distance, drainage frequency density, lineament frequency density, basin slope and stream order. These maps were used to rank and classify probable sites based on equal weight and statistical weight. The results were then used to classify the selected sites into four classes, namely sites with very high, high, moderate and low RWH potential. The proposed method was shown to be beneficial in the identification of potential RWH sites.

An automatic approach for rill network extraction to measure rill erosion by terrestrial and low‐cost unmanned aerial vehicle photogrammetry

AbstractFor an erosion event (October 2016) occurred at the Sparacia experimental area (Southern Italy), both terrestrial and low‐altitude aerial surveys were carried out by consumer grade camera and quadcopter (low‐cost unmanned aerial vehicle [UAV]) to measure rill erosion on two plots with steepness of 22% and 26%. Applying the structure from motion (SfM) technique, the three‐dimensional digital terrain models (3D‐DTMs) and the quasi three‐dimensional models (2.5D‐digital elevation model [DEM]) were obtained by the two surveys. Furthermore, 3D‐DTM and DEM were built using the available aerial photographs (166) and adding 40 terrestrial photographs. For the first time, the convergence index was applied to high‐resolution rill data for extracting the rill network, and a subsequent separation into contributing and non‐contributing rills was carried out. The comparison among the three surveys (terrestrial, UAV, and UAV + terrestrial) was developed using two morphometric parameters of the rill network (drainage density and drainage frequency). Moreover, using as reference the weight of sediment stored on the tanks located downstream of the plots, the reliability of soil loss measurement by 3D models was tested. For both contributing and non‐contributing rills, the morphometric parameters were higher for the terrestrial than for UAV and UAV + terrestrial surveys. For both plots, SfM always provided reliable soil loss measurements, which were affected by errors ranging from −8% to 13%. Although the applied technique used a low‐cost UAV and a consumer grade camera, the obtained results demonstrated that a reliable estimate of rill erosion can be obtained in an area of interest.

Terrain Characteristics and their Influence on the Temporal Behaviour of Hydraulic Heads in Kallada River Basin, Kerala

Abstract The terrain characteristics of an area play vital role in the spatial and temporal behaviour of the hydraulic heads of groundwater body. The present study was carried out to understand the influence of major terrain parameters such as slope, drainage, geology and soil characteristics on the seasonal variations of the hydraulic head in the Kallada river basin, South Kerala, India. Water table was measured at 166 open wells in the study area during pre-monsoon and post-monsoon periods to accomplish the objectives. Hydraulic heads in the study area varied seasonally from 0 to 4.33m during the study period. Wells with very less change in hydraulic head fall in the midland area, where the drainage frequency is very low to low. Areas with very high slope are characterized by less recharge and the wells at such areas show highest change in hydraulic head. Also, the wells with higher variation in hydraulic heads are associated with Kodumon, Mynagapally and Ummannur soil series.

Logistic Regression Analysis of the Risk Factors for Multidrug-resistant Bacterial Infections in Chronic Rhinosinusitis

Objective To analyze the risk factors of multidrug-resistant bacterial infections in patients with chronic rhinosinusitis.Methods The clinical data of 221 patients with chronic rhinosinusitis who were treated in our center from January 2010 to January 2017 were collected retrospectively. Specimens were collected for bacterial culture and antibiotic susceptibility testing. The risk factors for multidrug-resistant bacterial infections were analyzed.Results Univariate analysis showed that combined use of 3 or more antibiotics,high visual analogue scale score,high Lund-Kennedy score,long disease course(>5 years),high frequency of acute infections(more than 3 times a year),long duration of acute infection(>7 days),recurrent upper respiratory tract infections(>3 times per year),chronic otitis media,smoking history,allergic rhinitis,poor drainage,high frequency of antimicrobial use(≥3 times/year),use of multiple antibiotics(more than 3 types),aged over 60 years,and use of antibacterial drugs for over 7 days were the risk factors for production of multi-drug-resistant organism(MDRO) in patients with chronic sinusitis(all P<0.05). After adjusting for other factors,combined use of 3 or more antibiotics,high frequency of acute infections(more than 3 times a year),recurrent upper respiratory tract infections(>3 times per year),smoking history,allergic rhinitis,poor drainage,and high frequency of antimicrobial use(≥3 times/year) remained the risk factors for MDRO in patients with chronic sinusitis(all P<0.05).Conclusions Multidrug-resistant bacterial infections in patients with chronic sinusitis can be caused by a variety of factors. In the clinical practice,by focusing on the major risk factors,a comprehensive management strategy should be adopted to reduce the production of MDRO and improve the therapeutic outcomes.

Digital elevation model (DEM) coupled with geographic information system (GIS): an approach towards erosion modeling of Gumara watershed, Ethiopia

This study describes efforts to identify erosion-prone areas in the Gumara watershed using digital elevation model (DEM) data coupled with geographic information system (GIS). The software used to perform the overall analysis were the ESRI ArcGIS v10.3.1 with the ESRI Spatial Analyst and ArcHydro extension. All thematic layers (viz., slope, stream power index, drainage frequency, drainage density, drainage texture, relative relief, plan curvature, profile curvature) were integrated and analyzed in a GIS. A numeric evaluation scale from 1 to 4 was selected for ranking the subclasses of themes. The higher value, 4, represents higher impacts, while the lower value, 1, represents the lowest impact. About 21.71% of the total watershed area is under severe erosion zone. While 32.13%, 23.75%, and 22.42% of the total watershed area falls in moderate, low, and very low erosion zones respectively. In this paper, the numerical classification scheme presented constitutes an integrated approach that shows how to leverage basic watershed information to demarcate erosion prospective zones and measures at various scales for the purposes of watershed management.

Morphometric assessment and sub-watershed prioritization of Khari River basin in semi-arid region of Rajasthan, India

Watershed management is very crucial for arid and semi-arid regions dealing with limited availability of water resource. Morphometric assessment and prioritization studies provide basic criterion for effective local level watershed planning and natural resource management. The present study is an attempt to analyze morphometric characters of the Khari River basin and prioritize the sub-watersheds on the basis of ground water potentialities indicated by morphometric parameters using GIS approach. Khari River is semi-arid ephemeral; it is a tributary of Banas River, an important river of central Rajasthan (India). The basin has been subdivided in five sub-watersheds namely SW1 to SW5. Linear, areal, and relief parameters are calculated for Khari basin as well as for each sub-watershed. Morphometric parameters that are related to groundwater potentialities are ranked and compound factor values are calculated for each sub-watershed and priority is allotted based on these values. First priority is given to the least value of compound factor that indicate most deficit ground water condition. Overall results illustrate that Khari is a sixth-order stream and covers 6205 km2 area. Dendritic pattern is observed in Khari and in all the five sub-watersheds that indicate homogenous nature of underlain material and less structural control in the topography. Presence of low bifurcation ratio, low drainage density, and low drainage frequency values are favorable parameters of good permeability, infiltration in the basin, further gentle slope, coarse drainage texture, moderate to low relief, and elongated shape—all these parameters indicate good groundwater potentialities in major portions of the basin. Prioritization results show that the sub-watershed SW4 is at first priority with most deficit groundwater potential in comparison to other sub-watersheds and require water conservation measures. Sub-watershed SW4 has high values in linear parameters and low value in shape parameters that specify for poor groundwater potential, less permeability and high runoff, etc. Sub-watershed SW5 on contrary has indicated highest ground water potential in comparison to other sub-watersheds of the basin. The study provide local drainage morphometric information and preliminary prioritization for better water resource management in semi-arid region to achieve water self-sufficiency and sustainability at basin level.

Flash Flood Risk Estimation of Wadi Qena Watershed, Egypt Using GIS Based Morphometric Analysis

Flash flooding is one of the periodic geohazards in the eastern desert of Egypt where many parts of Upper Egypt, Sinai, and Red Sea areas were hit by severe flash floods, for example in 1976, 1982, 1996 and January 2010. The hazard degree for each sub-basin was determined using the approach developed by El-Shamy for assessing susceptibility of sub-basins to flash flooding risk. To identify at-risk sub-basins, two different methods were applied. The first method is based on the relationship between the drainage density and bifurcation ratio, and the second one uses the relationship between drainage frequency and bifurcation ratio. The three morphometric parameters (the bifurcation ratio, drainage density, and stream frequency) were extracted and calculated for each sub-basin of the watershed. Based on the final hazard degree resulting from the two methods, a detailed hazard degree map was extracted for all sub-basins. The results illustrate that there are no sub-basins with low risk of flooding. The sub-basins with the highest hazard degree are concentrated in the middle of the watershed although they have smaller areas compared with the surrounding sub-basins. The sub-basins located at the boundary of the watershed have an intermediate risk of flooding and moderate potential for groundwater recharge. This constructed map can be used as a basic data for assessment of flood mitigation and planning.

Hydro-geomorphological characterization of Dhidhessa River Basin, Ethiopia

Dhidhessa River Basin is physio-graphically and hydrologically important in the Blue Nile basin, however, its morphometry and hydrology are not well known. This study aimed to characterize hydro-geomorphology of the basin via basin morphometry analysis. SRTM DEM, geological and hydrological maps of the area were used in ArcGIS 10.3 environment for this analysis. Results showed that a 33,468 km total stream length of all orders was found distributed within 28,637 km2 drainage area in a dendritic pattern. According to morphometric parameter classification, total stream length and stream order of the basin were high whereas stream length ratio, bifurcation ratio and hydrologic storage coefficient were low. Furthermore, drainage area was large, drainage frequency was coarse, basin shape was more elongated, drainage density was medium, infiltration number was low, overland flow was long and constant of channel maintenance was high. Moreover, the basin's relief, relief ratio, ruggedness number, gradient ratio and the slope was high. In general, the study asserted that the basin was underlain by uniform resistant rocks, less prone to flooding, with high water resources potential and susceptible to soil erosion. The morphometric analysis approach pursued in this study was cost- and time-effective for basin characterization.