Drainage Frequency Research Articles

Meta-analysis of GHG emissions stimulated by crop residue return in paddy fields: Strategies for mitigation

The stimulating impact of crop residue return on greenhouse gas (GHG) emissions from paddy fields have been widely accepted, while the influence of site environmental and human factors on the simulating degree remains unclear. Here, we performed a meta-analysis to assess the GHG emissions affected by residue return, and its mitigation potential combined with key factors in paddy fields. Drawing upon 1047 observation sets of CH4 and N2O emissions from 155 peer-reviewed publications we found that residue return to paddy fields caused an average increase of 73% CH4 emissions and 14% in N2O emissions. Utilizing meta-analytical models, we identified pH as the most significant driver modulating GHG emissions, followed by soil organic matter (SOC) and total nitrogen. In alkaline soils, combining straw return with intermittent irrigation (285.2%) or mid-season drainage (118.9%) significantly reduced CH4 emissions compared to continuous flooding (1201.9%). Additionally, pairing straw return with higher nitrogen inputs (above 150 kg N ha−1) improved soil N2O uptake by −11.5%. In acid and neutral soils, straw carbonization achieved soil CH4 negative emissions (from −2.9% to −39.3%), but the long-term effects remained unclear. Reduced drainage frequency mitigates N2O emissions but may increase CH4 emissions. To efficiently mitigate GHG emissions, we proposed low-carbon schemes for acid or neutral soils based on specific SOC content: For soils with SOC content <10 g kg−1, prioritize nitrogen input control with rates not exceeding 174 kg N ha−1. For soils with SOC content >10 g kg−1, prioritize adjusting the type of straw. Our study underscores the significance of site-specific factors in modulating GHG emissions. Efficient GHG mitigation can be achieved by combining residue return with other agronomic measures tailored to different soil conditions.

Spatio-Temporal Analysis of Erosion Risk Assessment Using GIS-Based AHP Method: A Case Study of Doğancı Dam Watershed in Bursa (Türkiye)

Soil erosion, one of the most serious phenomena in watershed management, can be estimated based on various criteria. Land use change is one of the most important factors affecting the susceptibility of soil erosion. In this study, the effect of land use change on soil erosion risk in two plan periods (2005 and 2017) was investigated using Analytical Hierarchy Process (AHP) and Geographic Information Systems (GIS) for the forest planning units in the Doğancı Dam Watershed, located in Bursa, Türkiye. Eight criteria were evaluated including erosion-related slope, bedrock type, land use/land cover, precipitation, relative relief, aspect, drainage frequency, and density. According to the results, the most effective factor in soil erosion was slope (0.29), while bedrock type and land use/land cover ranked second with 0.19. It was found that full closure forests were characterized by high erosion resistance (0.3), while bare land was characterized as the most sensitive area to erosion (0.39). In terms of spatio-temporal changes in a 12-year period, the areas in the medium and high erosion risk decreased, while low and very low-risk areas increased. The ROC method showed a satisfactory accuracy of 72.8% and 80.2% for the 2005 and 2017 erosion risk maps, respectively.

An integrated statistical-geospatial approach for the delineation of flood-vulnerable sub-basins and identification of suitable areas for flood shelters in a tropical river basin, Kerala

Flood vulnerability assessment is crucial for developing effective flood management and mitigation strategies. The present study aims to understand the flood vulnerability of the Kallada River Basin (KRB) and identify suitable locations for safe flood sheltering facilities in the basin. As part of this, morphometric analysis of KRB was carried out by dividing the basin into fifty-eight 4th-order sub-basins to understand the sub-basin-wise terrain characteristics and the degree of vulnerability to flooding. GIS tools were used to assess various morphometrical parameters, such as drainage frequency, texture ratio, ruggedness number, basin relief, bifurcation ratio, length of overland flow, drainage density, circularity ratio and area, and geo-environmental factors such as sand percent, rainfall, and mean slope of these basins. The morphometric parameters exhibited distinct spatial trends, with higher values primarily concentrated in the east and northeast parts for certain parameters and in the western parts for others. Using hierarchical cluster analysis, the sub-basins were categorized into six clusters, revealing that 51% were vulnerable to floods, 26% moderately vulnerable, and 22% not vulnerable. Sub-basins in the central and western KRB were found to be highly vulnerable to flooding, while those in the eastern parts showed moderate vulnerability or were not vulnerable. Flood vulnerability mapping was validated using flood data of 2018 and 2019. Additionally, the weighted overlay method identified suitable areas for flood shelters in moderately vulnerable and vulnerable sub-basins and the areas were categorized into highly suitable, suitable, moderately suitable, and not suitable areas. Most areas of SB53 and SB55 were found highly suitable, emphasizing their potential for flood shelter locations. The findings of this study can be used by competent authorities to initiate flood mitigation and to develop targeted flood preparedness measures in similar river basins, particularly in the context of increasing flood events.

A Case of Cancer of Unknown Primary Presenting with Chylothorax.

A 56-year-old man presented to our hospital with dyspnea on exertion for two months. Bilateral pleural effusions were found, and a close examination revealed a chylothorax, including adenocarcinoma. The primary tumor could not be identified by systemic examination. Therefore, the patient was diagnosed with cancer of unknown primary origin (CUP) presenting with chylothorax. Chemotherapy was administered for CUP, and thoracentesis, pleurodesis, ascites puncture, and nutritional therapy were performed for chylothorax and chylous ascites. Although drainage frequency and tumor marker levels (CA19-9, DUPAN-2, and Span-1) temporarily decreased, disease control deteriorated, and the patient died 12 months after the initial diagnosis.

Identification of Water Resource Potential Zones of Baghmundi Block in Purulia District, West Bengal

Remote sensing and GIS techniques have been broadly used to determine the water resource potentiality for the development and management of water resources. It is an important natural resource in our daily life and is used for domestic purposes. It’s amount varies from place to place and season to season. It is scarce during the dry season, but in the rainy season, it is plenty. Assessment of water resource potentiality is very important for the management of surface/groundwater resources. Water resource potential zones are delineated with the help of RS &amp; GIS. In this paper, standard methodology has been used to delineate the water resource potential zones using Rs &amp; GIS techniques. Different parameters have been considered for identifying the water resource such as drainage frequency, drainage density, geology, groundwater level, slope, soil, surface water bodies, and land use/land cover have been generated satellite data and Survey of India (SoI) toposheet of a scale 1:50,000. Suitable ranks are assigned to these parameters. Various thematic maps of each parameter have been prepared by using the 'Ordered Weighted Averaging' technique. Finally, the composite map is generated by assigning all the parameters to demarcate the water resource potential zones. The study area has been classified into five categories: very poor, poor, moderate, good and excellent. This suggested methodology has been used to achieve the goal of the objective of the study area. This paper will be helpful for the identification of suitable locations for agriculture and domestic use of surface and underground water resources.

A Geographic Information System (GIS) based approach for drainage and morphometric characterization of Beki river basin, India

Geographic Information Systems and remote sensing, have proved to be efficient tools in delineation of drainage pattern and different geometric methodology of geomorphologic, watershed management even GIS has been widely used in several flood management, and environmental applications. The river Beki with an area of 19,354.35 sq.km2 originates at Himalayan glacier (Kula Kangri glacier in Bhutan) 26.18° N latitudes and 90.53° E longitudes and flows though the plains of Assam and finally to the mighty Brahmaputra at 26.48° N latitudes and 91.02° E longitudes has been selected for detailed morphometric analysis. Morphometric parameters via; Stream order, Stream length, Bifurcation ratio, Drainage density, Drainage frequency, Drainage texture, Form factor, Circularity ratio, Elongation ratio and Compactness ratio etc. were measured for prioritization and compound parameter values were calculated. This study will help the local people to utilize the resources in right manner for Sustainable Water Resource Development of the Basin area. Moreover, the study can also be referred as a benchmark for studies on temporal change in geomorphology due to climate change. Different Morphometric analysis provides the explanation of physical characteristics of the watershed which are useful for the areas of land use planning, soil conservation, terrain elevation and soil erosion.

Application of GIS and Remote Sensing Techniques for Hydromorphometric Analysis of Wadi Al-Mohammadi Basin, Western Iraq

Hydromorphometric analysis as a method is considered one of the most reliable and used methods in solving hydrological problems. Where it is possible to know the volume of runoff and the rest of the elements that enter into the water balance. Geographical Information System and Remote Sensing is the technique that used the hydro-morphometric analysis of the Wadi Al-Mohammadi basin. Wadi Al-Mohammadi, located in the Western Desert, is one of the main valleys that flow into the Euphrates River. It is considered an important basin, because of its many characteristics, including its relatively large area and the amount of water drained through, which is used mainly in watering livestock and agriculture, in addition to industrial purposes such as the production of washed sand, gravel that scattered on both sides of the valley. The hydrological analysis included several steps, which gave the results of the flow accumulation with the highest value in the lower part of the basin. The results represented by form characteristics confirm that the shape of the basin is far from the round shape, which reflects the basin’s characteristics with the regular surface flow in time and relatively low drainages. Wadi Al-Mohammadi basin has reached the 5th order to flow into the Euphrates River. It has two types of drainage patterns, the dendritic pattern, and the parallel pattern. Wadi Al-Mohammadi basin is categorized as extremely low drainage density, very low drainage frequency, very coarse drainage texture, lower infiltration number, and low relief slope. Based on the results, the basin is characterized by an almost flat plateau surface, with a gradual slope homogeneous and good permeable soil conditions, and in other parts influenced by the structural phenomena under the surface, the high permeability of sediments over which streams pass, higher the infiltration and lower runoff.

Morphological characteristics of Kanthatmakur vagu Watershed of Warangal District: Using Geographical Information System (GIS)

The present study relates to the morphometric analysis of Kanthatmakur vagu watershed using GIS. The GIS platform facilitates the analysis of various morphometric parameters. This watershed has higher order of 5th order. The present study has area of about 440.4 Km2 with total length of basin is 45.5 Km. Total number of streams in the basin is 635, ranging from 10 to 319. The basin area exhibits dendritic drainage pattern with bifurcation ratio ranges from 0.1 to 9.2, with mean bifurcation ration of 3.4. Length of stream of all orders are 481.8 km. Length of overland slow is 0.55 km and perimeter of the basin found to be 119.7 km. Areal aspects such as drainage density is calculated as 1.1, drainage frequency is 1.4 and drainage texture calculated as 5.3. Infiltration number of the watershed is 0.8. The watershed has 0.3 form factor ratio, 0.5 elongation ration and 0.4 circularity ratio. Relief of the watershed is 261m and ratio of relief is 6.3. The characteristics of morphological analysis of the Kanthatmakur vagu watershed has peak flow, is an elongated and less probable to flooding as well as moderate to slightly steep slope. In the watershed infiltration is high and run off will be low.

Supraglacial lake expansion, intensified lake drainage frequency, and first observation of coupled lake drainage, during 1985–2020 at Ryder Glacier, Northern Greenland

Along the Greenland Ice Sheet margin, supraglacial lakes store and redistribute ice sheet surface run off, and comprise an important potential hydrological link between the ice surface and the base, with ramifications for subglacial drainage systems and ice flow. As a consequence of increasing global mean surface air temperatures, these lakes have been predicted to expand further inland and to affect larger areas of the ice sheet. However, as contemporary dynamics of such supraglacial lake expansion are not well studied, any assessment of their future implications remains afflicted with uncertainty. Here, recent changes in supraglacial lake distribution and expansion, and in their drainage behavior and frequency, are presented for Ryder Glacier, Northern Greenland, as concluded from a remote sensing based analysis. The 35-year time span covered in the analysis allows for the detection of trends in lake processes and ice velocity, which otherwise were found to exhibit large inter-annual variability. It also reveals the first occurrence of a coupled lake drainage event in 2002. By linking supraglacial lake expansion, drainage modes, and drainage frequency to the efficiency of the subglacial drainage system and ice flow on seasonal and decadal timescales, a contribution is made to better understand the complexity of coupled glacio-hydrological processes, and to help reduce uncertainties in predictions of future mass loss from the Greenland Ice Sheet.

Study on Nitrogen Loss Rules of Paddy Fields under Different Irrigation and Drainage Modes in Southern China

With the growing problem of agricultural nonpoint source pollution, it is an urgent issue to explore irrigation and drainage modes suitable for rice-growing areas in southern China. Barrel experiments were conducted to study the variation of NH4+-N, NO3−-N and TN concentrations in surface drainage and deep percolation water, as well as the rules of nitrogen runoff losses and leaching losses. Treatments included frequent and shallow irrigation (FSI), drought planting with straw mulching (DPS) and water catching and controlled irrigation (WC-CI). The results showed that the trends of NH4+-N, NO3−-N and TN concentrations in surface drainage were similar, and the N concentration gradually decreased with increasing drainage frequency. The trends of NH4+-N, NO3−-N and TN concentrations in deep percolation water were similar, rising to a peak within 5~7 days after fertilization and then gradually decreasing. NH4+-N loss load was the main form of N loss load in surface drainage and deep percolation water, which accounted for 42.06~89.16%. Compared with FSI, DPS significantly increased surface drainage and N runoff loss loads by 98.67% and 125.86%, respectively, while WC-CI significantly reduced them by 59.21% and 66.38%, respectively. Deep percolation water was reduced by 68.59% and 37.99% for DPS and WC-CI, respectively, and N leaching loss loads were reduced by 74.69% and 43.23%, respectively. Compared with FSI, the total TN loss load was significantly reduced by 76.69% and 43.34% for DPS and WC-CI, respectively, and the pollution control was better for DPS. WC-CI significantly increased rice yield by 7.31%, while DPS decreased by 0.95 % due to long-term water stress. Comprehensively considered, WC-CI has obvious advantages, which can reduce nitrogen loss and maintaining a high yield.

Remote sensing and GIS based morphometric characterization of Bichiya river watershed of Rewa district, MP

Remote Sensing & GIS technique was used for extracting geomorphological characteristics of watersheds. Its application provides an efficient and accurate means for evaluation of these characteristics. Drainage system delineation is important to better understand hydrologic system, water resource management and its planning. Morphometric analysis of any drainage basin in a systematic method has a great importance in understanding hydrological behavior of the basin. Morphometric parameters describe the topology, the structure, the platform and the relief of basin area. Its characteristics are commonly used for planning & management of regional hydrological models. Physical characteristics of watershed provides some pre-information mainly runoff, stages of its development and soil loss productivity characteristics. Morphometric parameters viz; Stream order, Stream length, Bifurcation ratio, Drainage density, Drainage frequency, Drainage texture, Form factor, Circularity ratio, Elongation ratio and Compactness ratio etc. were measured for prioritization and compound parameter values were calculated and finally prioritization of seven sub watersheds was marked. Morphometric parameters are relevant and useful to identify various characteristics of drainage Watershed. Patterns, shape, stage of stream, as well as help to correlate with lithological characteristics. GIS and Remote sensing techniques have proved to be accurate and efficient tool in drainage delineation and their updation. Stream order show the Watershed is 5th order watershed with dendritic drainage pattern and with homogeneous nature and some area with parallel drainage pattern. The average Bifurcation Value of study area 2.98, usually these values are common in the areas where geologic structures do not exercise a dominant influence on the drainage pattern. The Drainage density of Watershed is 1.75indicating moderate drainage densities. The Moderate drainage density indicates the Watershed is permeable. It also shows the Texture of Watershed is Moderate.

An Assessment of Soil Quality and Agricultural Production Status in the Alluvial Soil Region: A Case Study in Koch Bihar District, West Bengal, India

Soil refers to the upper layer of the Earth’s surface, which is made up of a mixture of organic residues, clay, and rock particles, and that's where plants grow. The soil quality is the environmental aspect that is most significant in agricultural activities, as well as for the concern of the safety of agricultural produces. At present-day, soil quality assessment becomes the most important issue because of the raising food security awareness. This study was assessed in Koch Bihar district, West Bengal, India, to quantify soil quality using the weighted Soil Quality Index (SQI) approach. For this assessment, the soil-related data were collected from the Soil Health Card (SHC) of the Agricultural Development Offices in all blocks of Koch Bihar and then analyzed using the principal component analysis (PCA) and expert opinion (EO) method. The weights of the selected soil quality indicators were determined using the integrated Fuzzy-AHP model. According to this method, 12 indicators, i.e., soil pH, soil electrical conductivity (EC), soil organic carbon content, nitrogen content, potassium content, phosphors content, soil texture, the groundwater level in the winter season, cropping intensity, and drainage frequency were considered based on literature review. The SQI assessment was done accordingly for each spatial unit (Block), and the spatial variability of the soil quality map was produced by GIS spatial analysis module. The findings may aid in promoting non-harmful produce production, the provision of scientific data for agricultural structure adjustment, and the maintenance of agricultural sustainability.

Monitoring 13 years of drastic catchment change and the hydroecological responses of a drained thermokarst lake

Catastrophic drainage of thermokarst lakes transform portions of former lakebed to terrestrial settings, which have largely unknown consequences for the remaining aquatic habitat. Old Crow Flats, northern Yukon (Canada), is a lake-rich area that has recently experienced a climate-driven increase in lake drainage frequency. A notable example occurred during June 2007 when Zelma Lake (originally 12 km2) lost over 80% of its volume. Here we integrate remote sensing techniques with in-situ hydrological and limnological measurements over 13 years following drainage to 1) monitor water surface area and terrestrial land cover change and 2) identify associated effects on aquatic conditions. An airborne drone system was used to provide training data for land cover classification of AVIRIS-NG data, which indicated that tall willow shrubs covered 30.8% of the former lake area by 2017. Lake water isotope-derived deuterium-excess increased during the 13-year record indicating that hydrological input increased with greater snowpack accumulation within encroaching vegetation. Limnological conditions were highly variable and eutrophic during the first few years following drainage but became more stable as vegetation colonized the former lakebed. This long-term study provides insight of aquatic responses to thermokarst lake drainage and shrub vegetation proliferation, which are increasing in Arctic and subarctic regions.

Role of physico‐chemical properties of the soil in badlands forming processes around Chitrakoot, India

AbstractEco‐restoration attempts in badlands are generally not fully successful because physical solutions such as reshaping and leveling of gullies and ravines to check erosion and soil losses prove to be temporary in nature. In this context, it leads to conceptualization that the cause of badland formation is not merely topographical but should be related to changes in the intrinsic properties of soils. There is a lack of understanding as to the formative role of physico‐chemical characteristics of soils in the formation of badlands. The objective of our study is to determine such critical physico‐chemical characteristics of soils that are responsible for the onset of a self‐aggravating erosive network of badlands by undertaking a case‐study of part of the Mandakini River watershed, Chitrakoot, India. Standard IS codes were followed in determining these properties. These soils have a silt‐loam texture with high bulk density. Depletion of clays lowered Atterberg limits which consequently rendered the soils unstable even at low values of moisture content. The overlay analysis of these properties and drainage frequency shows perfect superimposition in categorizing badlands into zones of the severity of degradation. The chemistry of these soils has low sodium, high calcium with the presence of calcretes, low organic matter, and a low amount of illites and are mostly alkaline. The outcome of the study is helpful in understanding mutual interdependence between soil characteristics and processes of badlands that led to the intensification of rills‐gullies‐channels network. The findings would be useful in land management planning.

Morphometric Behavior of Shahzad Watershed, Lalitpur District, Uttar Pradesh, India: A Geospatial Approach

Morphometric parameters are an important aspect for understanding the hydrological and morphological behaviour of the watershed. The present study is carried out in the region of the Bundelkhand region (India) which is socio-economically backward and has a history of frequent drought hence studying the watershed characteristics with reference to morphometric analysis becomes important. The remote sensing and GIS technique has been utilized to mathematically quantify the parameters of the Shahzad watershed. The watershed is mainly fed by the Shahzad River (a tributary of Jamini River) flowing from south to north direction contributing the area of 1100 km2. The various morphometric aspect viz., linear, aerial, relief and morpho-tectonic parameters indicate that the watershed is elongated in shape and is slightly uplifted from the right side in the southern part. Moreover, the watershed experiences low dissection and low run-off discharge there by indicating less erosion in the area. The other factors like drainage density, drainage frequency, infiltration number and length of over land flow indicate that the watershed has high permeability and infiltration capacity. Through this study, it can be concluded that remote sensing and GIS can be fruitfully utilized in analysing the morphometric behaviour of the region. This helps the researcher, planner and stakeholders to establish the relationship between watershed characteristics, thereby resulting in watershed management and sustainable resource management.

Complex hydrological knowledge to support digital soil mapping

Drainage network (DN) is the representation of all the stream channels developed over the landscape. The morphometry of DN describes the relationship between channel characteristics and basin geometry, which is regulated by a series of processes, such as weathering, geomorphology, sediment erosion/deposition. The interaction between these factors impacts soil formation, resulting in a relationship between DN morphometry and soil characteristics. Unstable surfaces produced shallow soils, enhancing surface runoff and high drainage density, while stable landscapes favor vertical infiltration through old and weathered soils. Digital soil mapping has benefited from multiple environmental variables, such as relief and satellite data, but DN information can offer great contributions for the prediction of soil attributes. In this work, we applied a set of complex DN variables to perform digital maps of clay, sand, and soil organic carbon (SOC), for a 1378 km2 site in the São Paulo state, Brazil. We analyzed the relationship between the drainage density (DD), drainage frequency (DF), channel sinuosity, and confluence angle with soil classes and attributes. The Cubist and Random Forest algorithms were tested to predict the soil information, and to evaluate the impact of the new hydrological variables. The results showed that landscapes predominated by clayey soils favor surface runoff and increase channel formation, with higher channel sinuosity and acute confluence angles. These new drainage variables contributed 35 to 55% for SOC prediction. DD and DF were the most important drainage variables on the models, ranging from 65 to 70%. The external validation reached R2 of 0.72 and 0.56 for the prediction of clay and sand, respectively. The impact of DN information on the model performance suggests that more work is needed to better explore and understand the relationship between DN and soil information.

Prioritization of Flash Flood-Prone Areas in Small Coastal Basins around the Mediterranean Using Geomorphological Variables

The present study aims to model flash flood risk in small coastal watersheds in areas that are characterized by Mediterranean climate through extensive morphometric analysis which can prove invaluable for the investigation of flood risk, in ungauged watersheds, where flash floods are frequent. The available topographic data (EU-DEM) are analyzed through Geographic Information Systems (GIS) to produce all the secondary variables that are necessary for this morphometric analysis. Watershed prioritization techniques that are applied on geomorphological variables have proven to be an effective way of estimating the relative flash flood risk in a sub-watershed level. A series of morphometric parameters are used (bifurcation ratio, drainage frequency, drainage density, drainage texture, length of overland flow, circularity ratio, form factor, elongation ratio) which have an effect on flood risk. In small watersheds, with intermittent runoff, this effect can be different than in larger watersheds, so our methodology differs significantly from the methodology other researchers use. The compound factor is calculated by aggregating the assigned ranks of these morphometric indices and the sub-watersheds are prioritized according to their flash flood risk. The study area is located in the island of Samos, in Eastern Greece, where flood events are usual and pose a risk to villages and infrastructure around the island. The selected watershed (Imvrasos river) is divided into several sub-watersheds (W-1 to W-8) and a series of morphometric indices are calculated and evaluated through statistical procedures and by applying prioritization techniques, in order to locate the sub-basins that have the highest risk to flash floods. Sub-watersheds W-2 and W-3 (on the southern part of Imvrasos area) show the highest prioritization values, and should be prioritized for better watershed management planning.

Pleural Drainage Strategy After IPC Placement: A Focused Clinical Review.

The first indwelling pleural catheter (IPC) received Federal Drug Administration approval in 1997, nearly 40 years after John Chambers first described instillation of talc into the pleural space for palliation of malignant pleural effusions. Since then IPCs have revolutionized the management of malignant pleural effusions, providing an effective means of controlling dyspnea in the end stages of life without the pain and prolonged hospital stays long associated with chemical sclerosing agents. While palliation of symptoms is the primary purpose of IPCs, development of pleurodesis in the outpatient setting is often an important secondary goal. Historically, decisions regarding IPC drainage frequency have been largely arbitrary and only recently has the evidence started to emerge regarding the effects of specific drainage strategies on both symptom control and pleurodesis development. This focused clinical review explores the current literature regarding IPC drainage strategies as well as novel methods designed to improve the efficacy of IPCs in a thorough and systematic manner. In addition, this review provides an in-depth analysis and synthesis of the data focusing on key considerations needed to develop patient-centered and cost-effective strategies for the use of IPCs in malignancy.

Flash Flood Risk Assessment of Wadi Degla Basin Protected Area, East of Maadi, Cairo, Egypt Based on Morphometric Analysis Using GIS Techniques

The Wadi Degla basin is amongst the most important basins in the north-eastern part of the Eastern Desert, east of Maadi, Cairo, which drains into River Nile. It covers an area of about 177.6 km2. Although it located in an arid region, the basin could receive a huge amount of rainwater during heavy rainstorms which in turn lead to initiate flash flood hazard and causing catastrophic effects on existing infrastructure of main gate and tracks of protected area, also threatened visitor's life and surrounding environments. The present study aims to evaluate of flash flood risk in Wadi Degla and possible mitigation. The morphometric parameters investigation were carried out using ASTER Digital Elevation Model (DEM), GIS, and geomorphic field observations. Using a technique given by El-Shamy, the risk degree for the Wadi Degla basin's vulnerability to flash flooding risk was calculated. The first technique focuses on the relationship between drainage density and bifurcation ratio, whereas the second relies on the relationship between drainage frequency and bifurcation ratio. For the examined basin of the watershed, the third morphometric parameter (the bifurcation ratio, drainage density, and stream frequency) were obtained and calculated. The bifurcation ratio, stream frequency, and drainage density all have values of 1.7, 6.05, and 2 according to morphometric study. The bifurcation ratio, stream frequency, and drainage density have morphometric values of 1.7, 6.05, and 2 respectively, as per morphometric analysis. The Wadi Degla has elongated shape. According to the computed metrics (e.g., stream frequency, bifurcation ratio and drainage density), the Wadi Degla basin catchment area falls into category (A). This means that there is expected high susceptibility of flash flooding possibility in the area under consideration. This expected risk leads the Ministry of Water Resources and Irrigation to establish three dams on the pass of Wadi Degla to work as an obstacle for decrease the flash flood velocity flow. Consequently, from an environmental hazards point of view, the Wadi Degla Protected Area should be closed during heavy rainfall for visitor safety and also avoid the establishment of any basic infrastructure in the vicinity of the Wadi pass.

Landslide Susceptibility Zonation Mapping Using Bivariate Statistical Frequency Ratio method and GIS: A Case Study in Part of SH 37 Ghat Road, Nadugani, Panthalur Taluk, The Nilgiris

Landslide is more universal calamity in mountain areas. It is a threat to life and socio-economy. The ghat section Calicut–Nilampur–Gudalur State Highway 37 (SH-37) comes under the Survey of India toposheet 58A/7. It is important road network to connect Calicut. The study area is covered in 6.5 km ghat section of 103/6 to 109/8 km stone on SH 37. This study was carried out to prepare landslide susceptibility zonation (LSZ) mapping on 1:50,000 scale using frequency ratio model. Seventeen parameters such as elevation, slope, slope aspect, curvature, road buffer, drainage buffer, lineament buffer, land use, geomorphology, run-off, drainage density, drainage frequency, lineament density, lineament frequency, weathering condition, soil thickness and geology were considered as landslide-inducing factors. LSZ map was organized by manipulating association between the landslide persuade factors and old landslide using this model. Study area has grouped into five levels of susceptibility groups such as very low, low, moderate, high and very high. The LSZ map was validated by the old landslide record data collected from field. The landslide inventory percentage fall in very low hazard is 1.02%, 1.03% under low-susceptibility, 7.22% in moderate-susceptibility, 39.18% present in high-susceptibility and 51.55% noticed in very high-susceptibility zone, and using these data, the 18 rock vulnerable cut slopes were identified.