Stream Length Research Articles

Stream‐breeding salamander use of headwater stream networks in managed forests of western Washington, USA

Abstract Stream‐associated amphibians are sensitive bioindicators in headwater streams across the Pacific Northwest moist coniferous forests of North America. Much of this landscape is intensively managed for timber. Forest Practice (FP) rules determine harvest prescriptions on most private lands in Washington State and cover over 3.7 million hectares. Under these rules, non‐fish‐bearing headwater streams receive buffers on at least 50% of the stream length, including FP Sensitive Sites that receive 15–17 m radius no‐cut patch buffers. We evaluated how torrent (Rhyacotriton spp.) and giant (Dicamptodon spp.) salamander relative abundance is influenced by headwater stream network features that correspond to FP Sensitive Sites. In particular, we examined how salamander relative abundance in the two most common FP Sensitive Sites, tributary junctions (TJs) and perennial initiation points (PIPs), compared to densities in non‐Sensitive Site stream reaches, hereafter branches. We also evaluated salamander relative abundance and two hydrologic characteristics, dry channel and seeps. We analysed data collected in 2006 and 2007 from 17 amphibian‐occupied, non‐fish‐bearing basins in Western Washington with managed forest ages 30–80. We found no relationship between torrent salamander relative abundance and PIPs and TJs or between giant salamander relative abundance and TJs compared to branches. Consistent with expectations, giant salamander relative abundance was less in PIPs than in TJs and branches, and less in first‐order than second‐ and third‐order streams. Conversely, torrent salamander relative abundance lacked a clear relationship to stream order. Giant and torrent salamander relative abundance showed a negative relationship with the proportion of dry channels, but torrent salamanders were observed in short reaches of surface water located in predominantly dry channels. Importantly, reaches with seeps had 123% (CI: +103% to +146%) and 81% (CI: +49% to +121%) greater relative abundance of torrent and giant salamanders, respectively, than reaches without seeps. Practical implication: Current FP rules protect select side‐slope seeps as another category of Sensitive Sites but may too narrowly define the criteria of seeps to protect the full range of those being utilized by stream‐breeding salamanders. Studies focused on seeps and adjacent stream channel characteristics may better inform features important to stream‐breeding salamanders.

Morphometric indices assessment: Implications for active tectonics in the upper Narmada Basin, central India

During the Palaeoproterozoic era, the Northern and Southern cratonic blocks of the Indian Plate came together and amalgamated. Farther, facilitated by the East-West trending central Tectonic Suture Zone, characterized by the Son-Narmada Fault/Lineament (SNF/L) and Central Shear (CIS) Zone, has long intrigued researchers due to its implications for active tectonics, particularly in the Narmada basin. In this study, we employ geomorphic and morphotectonic indices to elucidate the neotectonic activity in the Upper Narmada basin (UNB) of central India. Utilizing SRTM-DEM data, we analyze morphometric and morphotectonic parameters to shed light on the development of drainage patterns and active tectonics within the basin. Our findings reveal a pronounced influence of tectonics on basin evolution, as evidenced by high bifurcation ratios indicative of intense tectonic activity and elevated ruggedness values suggestive of heightened erosion susceptibility. The predominant ENE-WSW orientation of the Son Narmada South Fault (SNSF) and Son Narmada North Fault (SNNF), aligned with major lineament trends, exerts control over the Narmada River drainage network. Additionally, the high value (<50) of the asymmetric factor reveals the significant tectonic influence on the Upper Narmada basin, while the transverse asymmetric factor and stream length index values further corroborate the basin's susceptibility to active tectonics. Notably, the abrupt elevation changes (200–600 m asl) reflected by Dhuandhar, Kapildhara and other falls along the course of Narmada provide compelling evidence of neotectonic activity. Thus, we assert that morphotectonic analyses employing Digital Elevation Maps, satellite imagery, and SRTM-DEM data represent an efficacious approach for investigating complex basin morphotectonics.

Split Majoron model confronts the NANOGrav signal and cosmological tensions

In the light of the evidence of a gravitational wave background from the NANOGrav 15 yr dataset, we reconsider the split Majoron model as a new physics extension of the standard model able to generate a needed contribution to solve the current tension between the data and the standard interpretation in terms of inspiraling supermassive black hole massive binaries. In the split Majoron model the seesaw right-handed neutrinos acquire Majorana masses from spontaneous symmetry breaking of global U(1)B−L in a strong first order phase transition of a complex scalar field occurring above the electroweak scale. The final vacuum expectation value couples to a second complex scalar field undergoing a low scale phase transition occurring after neutrino decoupling. Such a coupling enhances the strength of this second low scale first order phase transition and can generate a sizeable primordial gravitational wave background contributing to the NANOGrav 15 yr signal. Some amount of extraradiation is generated after neutron-to-proton ration freeze-out but prior to nucleosynthesis. This can be either made compatible with the current upper bound from primordial deuterium measurements or even be used to solve a potential deuterium problem. Moreover, the free streaming length of light neutrinos can be suppressed by their interactions with the resulting Majoron background, and this mildly ameliorates existing cosmological tensions. Thus cosmological observations nicely provide independent motivations for the model. Published by the American Physical Society 2024

Exploring spatial variations in geomorphic features of a young intracontinental orogenic belt: A case study of the High Atlas range

Morphotectonic parameters are sensitive to crustal and/or mantle dynamics, especially in young convergent margins and contractional orogenic systems. In northwest Africa, the High Atlas orogen is a natural example where tectonics interact with mantle dynamics to shape the orogen's topography.The High Atlas Mountains are an intracontinental segment of the peri-Mediterranean belt in northwest Africa, formed during the Late Cretaceous-Cenozoic period as part of the Alpine orogeny. An important aspect in the evolutionary history of the High Atlas belt is the presence of uplifted asthenosphere beneath the range, overlaying the Late Cretaceous-Cenozoic crustal shortening. This study aims to investigate the geomorphic and topographic features that reflect the influence of tectonics and mantle dynamics in the High Atlas orogen. A morphotectonic approach is employed, utilizing analysis of geomorphic indices such as relief, slope, channel steepness index, and stream length gradient. Additionally, eleven 30 km wide and 150 to 230 km long swath profiles are constructed to illustrate the variations in topography and geomorphology along the range.The geomorphic indices display a similar pattern of evolution across the High Atlas, with higher values of these indices associated with the primary faults that control the structure of the range. By combining the geomorphic indices and swath profiles, it is evident that the eastern part of the orogen exhibits geomorphic asymmetry, with the northern border experiencing greater neotectonic activity and surface uplift. The central part of the range displays more geomorphic symmetry, while the western part is asymmetrical, characterized by higher elevations and elevated values of geomorphic indices along the southern border. This variation in geomorphology is attributed to the oblique intersection of the High Atlas orogen and a region of thinned lithosphere, which facilitated increased neotectonic activity and surface uplift in the northern part of the Eastern High Atlas and the southern part of the Western High Atlas. In the westernmost portion of the range, the role of structural inheritance is critical in the neotectonic activity. At a local scale, the role of lithology in the drainage reorganization is evident especially in basement exposures such as Mougueur inlier, Skoura inlier and Ouzellarh salient.This study underscores the robustness of tectonic geomorphology as a tool to understand the complex interplay between crustal processes and mantle dynamics, together with surface processes, in young orogenic belts like the High Atlas.

Assessment of active tectonics of the Tripura-Mizoram fold belt (Surma Basin), North East India

The Tripura-Mizoram fold belt is situated in the north-eastern part of India. Northeastern Himalaya including this region is tectonically very active, partly petroliferous, and has international attention from academicians and industry persons. This study aims at locating areas of recent tectonic vulnerability. Drainage networks are proxies of active faulting. Changes in geomorphic indices e.g., long profile analysis, basin-scale parameters, stream length gradient index and steepness index along the rivers in the eighteen watersheds extracted within the study area are evaluated. The Index of active tectonics (IAT) derived from the basin-scale parameters is classified into five classes: Class 1 (IAT =1.875–2.000), Class 2 (IAT = 2.001-2.375 ), Class 3 (IAT = 2.376-2.750), and Class 4 (IAT = 2.751-3.250) and Class 5 (IAT = 3.000‐3.320). Class 1 indicates the highest activity of tectonics. The tectonic sensitivity is also marked in micro-scale where rivers cross lineaments / faults. Elevations from source to mouth of individual consequent rivers of each watershed indicate the most vulnerable sections where the channels run along and across the faults or lineaments in watersheds 2, 14 and 15. The computed R2 values and the IAT identify watershed 2 and watershed 15 as the tectonically most active. Well-bore stability issue from the Petroleum mining lease (PML) blocks needs to be taken care from watershed 2, 3 and 15.

Tectonic evolution of Bursa Yenişehir Basin, Turkey from the Neogene to the Quaternary using a morphotectonic approach

In this study, the morphotectonic features of the Yenişehir pull‐apart basin in Bursa in northwestern Turkey were analysed. The faults in the region are the most important structural elements that characterize the morphology of the Yenişehir pull‐apart basin. The aim of this study is to show the deformation effects of these active faults on the geomorphology with some basic morphometric indices. The morphotectonic features were evaluated using the hypsometric curve and hypsometric integral (Hi), drainage basin asymmetry (the asymmetry factor (AF) and the transverse topographic symmetry factor (T)), river length gradient index, mountain front sinuosity, and valley floor ratio. The morphometric indices that play an important role in the analysis of catchment areas are the Hi, AF, and T indices, which indicate tilting and erosion activities. According to the results of the hypsometric curve and hypsometric integral, the Yenişehir Basin is a young basin with a uniform topography as expected in an active pull‐apart basin formed by faulting in the Quaternary. The relative tectonic activity index (Iat) of the study area was calculated using the values of hypsometric integral, transverse topographic symmetry factor, asymmetry factor, mountain front sinuosity, valley floor ratio and stream length gradient index. The Iat values indicate the tectonic activity of the basin from Pliocene to Recent. Three different tectonic classes were identified in the study area. These are class 1 (high relative tectonic activity), class 2 (moderate relative tectonic activity), and class 3 (low relative tectonic activity). The Iat classification data show that the impact of tectonic activity on the geomorphology is lower in the Iat class 3 indices than in the others. The Iat data show high tectonic activity in the region where active faults of the North Anatolian Fault Zone southern branch are located.

Differentially Private Stream Processing at Scale

We design, to the best of our knowledge, the first differentially private (DP) stream aggregation processing system at scale. Our system - Differential Privacy SQL Pipelines (DP-SQLP) - is built using a streaming framework similar to Spark streaming, and is built on top of the Spanner database and the F1 query engine from Google. Towards designing DP-SQLP we make both algorithmic and systemic advances, namely, we (i) design a novel (user-level) DP key selection algorithm that can operate on an unbounded set of possible keys, and can scale to one billion keys that users have contributed, (ii) design a preemptive execution scheme for DP key selection that avoids enumerating all the keys at each triggering time, and (iii) use algorithmic techniques from DP continual observation to release a continual DP histogram of user contributions to different keys over the stream length. We empirically demonstrate the efficacy by obtaining at least 16× reduction in error over meaningful baselines we consider. We implemented a streaming differentially private user impressions for Google Shopping with DP-SQLP. The streaming DP algorithms are further applied to Google Trends.

Morphometric analysis in the sub basins of the Kali River using Geographic Information System, Karnataka, India

Morphometric analysis serves as a crucial tool for quantitatively characterizing drainage basins and exploring the intricate relationships between hydraulic parameters and geomorphological characteristics. This study presents a comprehensive morphometric analysis of the Kali Subbasin in Karnataka, covering an area of 1175.45 km². Utilizing remote sensing data and GIS tools, we quantified various morphometric parameters, including stream order, stream length, bifurcation ratio, drainage density, stream frequency, form factor, and circularity ratio, to understand the basin's geomorphological and hydrological characteristics. The study area is classified as a seventh-order basin displaying a dendritic drainage pattern with a drainage density of 2.853 km/km². Notably, the bifurcation ratio ranges from 4.396 to 3, indicating low to moderate structural control within the basin. The subbasin's elongated shape, with an elongation ratio of 0.604 and a circularity ratio of 0.298, indicates moderate peak flow and high susceptibility to erosion. Relief parameters showed significant elevation variations, contributing to intense erosion and heightened flood risks in lower-lying areas. The study identifies the basin's transition to a mature geomorphic stage, evidenced by an escalating stream length ratio from lower to higher orders. These findings underscore the importance of tailored watershed management strategies, including floodplain zoning, retention basins, afforestation, and terracing, to mitigate flooding and soil erosion. The study's insights are crucial for developing effective, localized water resource management plans and enhancing the resilience of the Kali Subbasin to future hydrological challenges.

Projecting exceedance of juvenile salmonid thermal maxima in streams under climate change: A crosswalk from lab experiments to riparian restoration

Abstract Concern over rising water temperatures for freshwater ectotherms has led to application of experimentally derived thermal thresholds to stream temperature models for estimation of streams at high risk of exceeding thermal thresholds under current and future climate conditions. We optimised an approach that links field‐relevant thermal maxima experiments to corresponding stream temperature models and identifies opportunities to reduce stream temperatures through riparian tree growth. We conducted a thermal maxima experiment on cold‐water adapted juvenile Chinook (Oncorhynchus tshawytscha) and coho salmon (Oncorhynchus kisutch) that reflected natural temperatures by using incremental temperature ramping with diel fluctuations (IT‐Dmax) and refit a regionally specific stream temperature model for British Columbia, Canada to directly relate to lab‐derived thresholds. Salmon‐bearing streams across British Columbia were categorised by threshold exceedance risk (i.e., low, moderate, high, severe) based on risk tolerance scenarios for management decision making (i.e., considering a range of prediction intervals [PIs] and stream thermal sensitivities to air temperature). We linked these results directly to riparian management and restoration actions by estimating the potential for riparian tree growth to reduce threshold exceedance risk. Lab‐derived IT‐Dmax endpoints were consistently 24°C (based on the median value between the 7‐day average of the daily maximum and the mean weekly average temperature) across acclimation treatments for both species. Under current conditions, most stream reaches (99.6% using an intermediate risk tolerance scenario) were below the thermal threshold; streams with moderate to high risk of threshold exceedance were projected to increase from 0.4% to 1.5% (total linear stream length of 6,929 km) by end of century. The risk‐averse (high sensitivity, 75% PI) and risk‐tolerant (low sensitivity, 95% PI) scenarios differed by 1,107 km of streams predicted to have a moderate to severe risk of exceeding thresholds by end of century. Maximal riparian tree growth was predicted to shift 670 km of streams from moderate to low exceedance risk under end‐of‐century conditions and intermediate risk tolerance, showing the potential for mitigation from thermal impacts. Our integrative approach tackled several key considerations in identifying streams at high temperature risk for freshwater ectotherms that to date have not been addressed. Furthermore, we showcased the delineation of spatially comprehensive estimates that identify where management mitigation and a specific restoration activity may be most needed to reduce impacts of rising temperatures on rearing salmonids across an extensive region.

Assessing the level of river basin evolution, erosion susceptibility and its correlation with morphometric characteristics using Geoinformatics techniques

The application of Geoinformatics have become fastest and improved advanced tools to analyse and interpret the topography and hydrological characteristics. This study aimed to utilize the advantage of high resolution (30 m) remote sensing data of Shuttle Radar Topography Mission (SRTM) and the geoinformatic tools of Quantum Geographical Information System (QGIS) for extraction of detailed and accurate drainage morphometry and elevation information in preparation of hypsometric curves. Making use of QGIS, the SRTM data and topographic maps are georeferenced and pre-processed algorithm tools of stream burning and fill-DEM are applied for DEM preparation and extraction of accurate drainage network and its basin areas. From the DEM map, the details of elevation and area of basins are extracted for preparation of hypsometric curves. Hypsometric curves are analyzed to interpret and understand the heterogeneity in the levels of basin evolution/development and erosion at 4th order sub-basin level. The concave hypsometric curves of main basin and sub-basins indicate that total basin as well as sub-basins reached the old/monadnock stage due to the dominance of fluvial process. Based on the hypsometric area/integral (Ea) and Concavity of hypsometric curve values (Eh), five classes/stages of basin development and erosion levels are identified within the old/monadnock stage. The Ea values range from 0.10 to 0.35 and Eh range from 0.25 to 0.77 in this study area. Initial old/monadnock stage of basins have Ea values > 0.28 and Eh values < 0.4 indicating low levels of erosion among the sub-basins. Low hypsometric area/integral value (Ea) indicates the higher level of landmass removal by erosion and basin development. The oldest stage basins are identified with Ea values range from 0.10 to 0.15 and Eh values range from 0.61 to 0.77 indicating higher level of landmass removal/erosion. The lithological variation plays a significant role on hypsometry of the basins. The high hypsometric integral (Ea) values (i.e., 0.28 to 0.35) of 1,2 and 3 sub-basins indicating the early/ initial level of old stage in its’ basin development, since the resistant basalt formation is sandwiched between sandstones prevented deep erosion and depicting less dissected topography. The hypsometric integral has positive correlation with form factor and negative correlation with drainage morphometric characteristics. It indicates that the level of basin evolution increases as the form factor decreases but number of streams, length of streams, mean bifurcation ratio, relief, relief ratio and ruggedness ratio increases. This study is highly useful to understand the relation among morphometric characteristics, basin development and erosion levels through the analysis of hypsometric curves making use of Geoinformatic techniques.

UAV Mapping for Flood Routing in Steep and Densely Vegetated Areas: Insights from the Contok River Basin, Garang Watershed, Indonesia

This research utilizes photogrammetry to assess flood routing dynamics in the Contok river basin, a sub-watershed with a challenging landscape characterized by steep slopes, dense vegetation, and meandering patterns. The objectives are to assess Unmanned Aerial Vehicle (UAV) mapping accuracy, evaluate the river's capacity for design flood volumes, quantify the impact of land cover changes on surface runoff, and provide insights for early warning systems and watershed conservation strategies. The study area, encompassing the Contok River Basin, a sub-watershed of the Garang Watershed, covers 7,413 km² and includes a stream length of 5,274 meters in Semarang City, Central Java, Indonesia. This research employed image processing of aerial photographs and satellite imagery. Aerial photos captured using UAV data were utilized to derive elevation data and cross-sectional profiles of the Contok River, essential for understanding channel morphology and hydraulic characteristics. Concurrently, satellite imagery was used for land cover analysis, identifying vegetation and built-up areas that influence surface runoff dynamics. Hydrological analysis was performed to quantify discharge magnitudes, simulated against river cross-sections to evaluate flood behavior under varying scenarios. Our proposed UAV mapping provides adequate accuracy for small and local areas. Furthermore, it remains reliable for flood routing analysis. We discovered that the capacity of the Contok River channel in the downstream area allows it to convey design flood discharges up to a 50-year return period, contrary to the upstream area, it overflows. Notably, the shift from vegetated to built-up and agricultural areas significantly contributes to the 10.6% increase in surface runoff. This research highlights the role of UAV-based photogrammetry in assessing and mitigating flood hazards amidst evolving land cover patterns. It also enhances the understanding of flood dynamics and thus provides insights that will serve as a reference for flood early warning systems, flood management practices, and watershed conservation.

How do different runoff generation mechanisms drive stream network dynamics? Insights from physics‐based modelling

AbstractNon‐perennial river catchments are characterized by an ever‐changing spatial configuration of their flowing streams. A combination of empirical data and simplified analytical frameworks has been frequently used in the literature to analyse the co‐evolution of the total active stream length () and the catchment discharge at the outlet (). However, despite the increasing availability of field data, understanding how runoff generation processes drive the spatio‐temporal dynamics of non‐perennial river reaches remains challenging. In this paper we use CATHY, an integrated surface–subsurface hydrological model (ISSHM), to investigate the impact of saturation‐excess (Dunnian) and infiltration‐excess (Hortonian) runoff generation on the stream network dynamics of two virtual catchments with spatially homogeneous subsurface properties but different morphology. The numerical simulations show that when surface runoff is triggered by saturation‐excess mechanisms, the subsurface domain is slowly saturated, and the stream network gradually expands upstream from the outlet towards the catchment divides. In these conditions, the specific inflow per unit contributing area is relatively uniform along the network, thereby implying that and display a monotonically increasing one‐to‐one relationship. On the other hand, infiltration‐excess mechanisms lead to more heterogeneous saturation patterns in the subsurface domain. In particular, during the wetting phase, Hortonian processes originate highly transient conditions and a non‐uniform spatial distribution of the specific inflow along the stream network. This is reflected by a hysteretic relation and a marked asymmetry between the wetting and drying phases of the event. The application of an ISSHM proved to be a useful tool to elucidate the processes that drive stream network expansion and retraction in non‐perennial rivers.

Hyper-resolution flood hazard mapping at the national scale

Abstract. Flood hazard mapping is currently in a transitional phase involving the use of data and methods that were traditionally in the domain of local studies in a regional or nationwide context. Challenges include the representation of local information such as hydrological particularities and small hydraulic structures, as well as computational and labour costs. This paper proposes a methodology of flood hazard mapping that merges the best of the two worlds (local and regional studies) based on experiences in Austria. The analysis steps include (a) quality control and correction of river network and catchment boundary data; (b) estimation of flood discharge peaks and volumes on the entire river network; (c) creation of a digital elevation model (DEM) that is consistent with all relevant flood information, including riverbed geometry; and (d) simulation of inundation patterns and velocities associated with a consistent flood return period across the entire river network. In each step, automatic methods are combined with manual interventions in order to maximise the efficiency and at the same time ensure estimation accuracy similar to that of local studies. The accuracy of the estimates is evaluated in each step. The study uses flood discharge records from 781 stations to estimate flood hazard patterns of a given return period at a resolution of 2 m over a total stream length of 38 000 km. It is argued that a combined local–regional methodology will advance flood mapping, making it even more useful in nationwide or global contexts.

Quantitative assessment of relative tectonic activity in the eastern Bandung Basin, Indonesia

ABSTRACT The Eastern Bandung Basin is composed of predominantly Quaternary volcanic rocks and is influenced by tectonic activity. This research aims to determine and evaluate the morphotectonic characteristics and its implication to the potential geological disaster in the Eastern Bandung Basin. The morphotectonic indices used in this research consist of Stream Length Gradient Index (SL), Asymmetric Factor (Af), Hypsometric Integral (Hi), Ratio of the Valley Floor to the Height of the Valley (Vf), Basin Shape (Bs), and Sinousity of the Mountain Front (Smf). The research area consists of subwatersheds, namely Upper Citarik, Cijalupang, Ciwirama, Ciburial, Cikeruh, and Cimande. The research area is mostly located on hilly to mountainous area with flat to very steep slopes (0–56°). The research area is composed of Quaternary volcanic rocks in the north, east, and south as well as Quaternary alluvium in the central part of the research area. Based on the quantitative assessment, the research area has IRTA values of classes 3 and 4, indicating low to moderately active tectonics. It can be related to active faults and Quaternary volcanic rocks. Class 3 of IRTA corresponding to moderately active tectonics occurs mainly in the Upper Citarik and Cimande subwatershed. Class 4 of IRTA mainly takes place in the Cijalupang. Ciwirama, Ciburial, and Cikeruh subwatershed.

A machine learning model for estimating the temperature of small rivers using satellite-based spatial data

The influence of anthropogenic activity and land cover alteration on stream temperatures has major ecological implications, such as limiting fish survival. While these ecological impacts have been extensively studied at varying spatial scales for major rivers, our understanding of the range and complexity of this relationship across climates and geographies for smaller rivers (less than ∼60 m wide) remains limited. This is in part because although such rivers comprise a vast majority (∼97%) of total stream length, most smaller rivers lack routine temperature observations despite extensive gage networks. While existing gage networks in many regions are sufficient to support satellite remote sensing-based modeling of small stream temperatures, most large regions including the contiguous United States do not have modeled data products at high spatial and temporal resolution for small rivers.In this study, we developed a statistical model, TempEst (“temperature estimation”), to estimate monthly average water temperatures for smaller rivers and evaluated the model with rivers ranging from 3 m to 1000 m (1 km) in width, using land cover, topography, and satellite-based land surface temperature. The rivers chosen for development of the model are representative of a range of urban and rural land uses and cover eight US Environmental Protection Agency Level I ecoregions. The model was calibrated and validated using observed stream temperatures from the United States Geological Survey. TempEst is able to predict monthly average temperature for streams of any size with an overall median RMSE of about 1.5 °C and bias of 0%. Model accuracy has a consistent trend with training gauge network density, with median RMSE increasing to about 2.0 °C in more sparsely-gauged regions. As a simple demonstration, we used TempEst to estimate thermal suitability conditions for cutthroat trout in Rocky Mountain streams in the United States. The developed model, available as open-source R (model) and Google Earth Engine (data retrieval) scripts, will facilitate the study of stream temperature behaviors at higher resolutions than previously available across the contiguous United States and can be easily adapted to support global river systems.

Design of Rain Water Harvesting System for Efficient Water Scarcity and Flood Management in India

Areas experiencing extensive floods during the rainy season and water scarcity in winter require efficient water resource management. Economical water-harvesting structures such as drystone masonry and upstream-wall cement masonry, with heights ranging from 1 to 2.5 meters, are constructed for catchments smaller than 10, 10 to 20, and 20 to 30 hectares, respectively, utilizing locally sourced materials. These constructions offer significant cost-effectiveness for the location, boasting a B:C ratio of 3.5:1. In certain areas of Assam, Garh structures are constructed, featuring large and lengthy embankments on both sides with an open central section for water flow. Within paddy fields, the entire area is partitioned into small square segments, creating small embankments known as "Dara." which store rainwater for cultivation. Across the entire Western Himalayan region, encompassing Jammu, Himachal Pradesh, and Northern Uttaranchal, Guhl serves as a standardized water harvesting technique. Notably, in Akola and Chittoor districts, the establishment of farm ponds has significantly boosted crop and livestock productivity, along with farm income. Additional irrigation has notably enhanced the yield of various rainfed crops such as pigeon pea, chickpea, groundnut, cotton, and vegetables, as well as mango and coconut plants, with improvements ranging from 5 to 72%. With the availability of harvested rainwater for supplemental irrigation, farmers have also planted additional fruit trees, resulting in increased productivity of existing fruit trees, such as mango (39%) in Chittoor district and coconut (51%) in Vellore district. Expanding the number of rainwater harvesting structures could potentially reduce runoff within the basin by up to 60%. The implementation of Doha Models, involving percolation tanks dug along the length of lower-order seasonal streams in Jalna district of Maharashtra, has increased cropping intensity from 129% to 132%. Remarkably, five out of seven crops have demonstrated a relatively higher percentage increase in yields. The optimal productivity of harvested water is achieved when efficient application methods such as micro-irrigation are employed, targeting high-value crops.

Morphometric analysis of Mogamureru river basin at the YSR Kadapa District, Andhra Pradesh, India using GIS and remote sensing

Water availability and scarcity are impacted by geomorphological changes that occur within a catchment. As a result, determining the influence of geomorphological processes on the catchment’s hydrology requires a quantitative study of the catchment geometry. Approaches based on remote sensing (RS) and geographic information systems (GIS) have grown in popularity in recent years because they assist strategists and decision-makers in making accurate and effective choices and plans. For this research, the Mogamureru River basin was chosen. The study shows that GIS and RS data can be used to analyse and approximate the period and erosional operations’ risk in a Mogamureru river basin for better design and maintenance. The quickest and most economical method of displaying the hydrologic and physiographic features of the Mogamureru river basin is to assess the morphometric parameters. All of the following parameters such as: linear (7) areal (5), relief (5), and drainage texture (5) characteristics were obtained with hypsometric curve for the Mogamureru river basin utilizing the Shuttle Radar Topography Mission (SRTM) images. According to the linear parameter values, the majority of streams (82 %) belong to the first order, Statistical analysis shows that there is a good relationship between stream order and stream length, as well as stream order and stream number. The circularity ratio (0.55) depicts the young, elongated topography. The basin as a whole is in the mature stage of formation, with good to moderate potential, according to the hypsometric index (0.46). Due to land deterioration, Pulivendula and Vemula have had the most soil loss. This study concludes that morphometric analysis based on GIS & remote sensing techniques is a competent tool for hydrological studies. The research findings will help policymakers for integrated river basin management, agricultural development, and water management. In addition, researchers of morph hydrological, geological and climatological research will be beneficiary.

Analysis of morphometric characteristics and prioritization of micro watersheds of Karamnasa River Basin using remote sensing & GIS technique

ABSTRACT The Karamnasa River, originating in Bihar’s Kaimur district, serves as a vital water resource in the region. This research, conducted at coordinates 25°30’54’‘N latitude and 83°52’30’’ E longitude, aimed to identify optimal sites for water conservation structures within the Karmanasa River Basin (KRS) using Remote Sensing and GIS techniques. By analysing morphometric parameters (MP) of the basin, including slope, stream length, and drainage density, the study delineated the basin into seven sub-watersheds and five stream orders. The comprehensive analysis revealed SW2 as the most critical sub-watershed, necessitating immediate conservation efforts. Assigning ranks to parameters like bifurcation ratio and circulatory ratio, SW2 emerged as the priority sub-watershed. Fifteen potential conservation sites were identified, comprising 9 farm ponds, 3 percolation tanks, and 3 check dams. The research underscores the significance of prioritizing sub-watersheds based on morphometric characteristics, with lower parameter values indicating higher priority. The study’s drainage network analysis, conducted through remote sensing and GIS, enhances understanding of the KRS hydrological features. This research highlights sustainable development through effective water resource use and targeted conservation in the Karamnasa River Basin, emphasizing community engagement and participatory methods for enduring, resilient environmental stewardship and successful land management.

Community Detection Using Modularity Optimization Method For Catchment Classification

A general framework for catchment classification may be helpful for more accurate and efficient modeling of hydrologic systems, as well as to improve communication between hydrology researchers and those in other disciplines. There are plethora numbers of methods applied for catchment classification, but in these years, recent studies are implementing the complex networks concept for classification purposes. The community structure methods which are complex networks-based methods are focus mainly to classify catchments. Hence, the efficiency of complex network ideas, especially using the methods of community structure is examined in this study. Specifically, the modularity optimization method that is one of the community structure methods is applied to classify 218 stream-gauges stations in entire Australia that covers a large variety of hydroclimatic, topographic, geomorphic, soil usage, and climatic parameters. In the present study, the applicability and the efficiency of the community structure concept is validated by the proposed method. The classification of Australian catchments was further assessed with threshold value of 0.8, which resulted formation of nine communities with at least 9 stations in a community which combine to have almost 77% of the total number of stations (165 out of 218). All nine selected communities were also examined in terms of the flow characteristics (i.e. flow mean and flow covariance) and the catchment characteristics (i.e. drainage area, elevation and stream length). The catchment behaviors for each selected communities were also interpreted in terms of distance and correlation relationship, which give some useful insights towards generalization of hydrologic framework.

Morphometric characteristics of block streams: A case study of the Vladayska River basin, Vitosha Mountain (Bulgaria)

Block streams, also known as stone rivers, are common periglacial landforms in the alpine and subalpine zone of the Balkan Peninsula. These features are especially widely spread in the valleys, slopes and summit of Vitosha Mountain. The presented research aims to estimate the total area of block streams and perform morphometric analysis of these landforms within the basin of Vladayska River. Block streams are digitized man-ually from orthophotographs and topographic maps using GIS software. Morphometric parameters such as area, length, width, elongation ratio and mean elevation are calcu-lated or extracted from a digital elevation model for each polygon. A linear regression test was conducted to evaluate the relationship between morphometric properties. Results indicate a significant correlation between the area and perimeter (R2 = 0.93) and between the length and width (R2 = 0.94) of the block streams. Block streams are present in the elevation range between 1177 and 2244 m, covering a total area of 169.7 ha. The largest ones occupy the area of Zlatnite Mostove and Yurushki Most, as well as the vicinity of Cherni Vrah Peak. Their length varies from 5&amp;ndash;6 m up to 2.2 km, while their width changes from a few meters up to 0.6&amp;ndash;0.7 km. Comparisons between block streams from different sites within the catchment area yield new insights into the diver-sity of these landforms. Their dimensions and spatial distribution are key to understand-ing the processes of their formation and evolution.