River basins play a pivotal role in the hydrological and geomorphological systems of a region, influencing water availability, sediment transport, and the overall landscape evolution. The Barakar River, a significant tributary of the Damodar River, contributes to the water dynamics of Jharkhand and West Bengal. The region surrounding the Barakar River is characterized by varying topography, including hills, plains, and lowlands, making it essential to study its geomorphological features for effective basin management and flood mitigation.

River basin studies using hypsometric and morphometric analysis provide insights into the terrain's evolutionary status and erosion potential. As human activities and climate change continue to impact river systems, understanding their current geomorphic stages becomes increasingly critical. In particular, the Barakar River Basin has not been extensively studied in terms of its geomorphological evolution, despite its hydrological significance. This study aims to bridge this gap by employing modern geospatial techniques to comprehensively evaluate the basin's characteristics and stage of development. Hypsometric and morphometric analyses have long been used to assess the geomorphic development and erosional status of river basins. According to Strahler (1952), the hypsometric integral is a valuable tool for evaluating the geomorphic maturity of a basin, where higher HI values indicate youthfulness, and lower values suggest an older, more eroded landscape. Strahler's stream order classification method has also been extensively applied in morphometric studies, helping to identify the complexity of drainage networks (Horton, 1945). These analytical tools, when integrated with modern GIS technology, have provided researchers with the ability to model and quantify various geomorphological parameters.

Several recent studies have focused on using GIS to assess river basins. For instance,Singh, Kumar, and Singh (2014) used morphometric analysis to evaluate the hydrological response of the Gomti River Basin, revealing significant variations in basin shape and drainage characteristics that were linked to flood potential. Similarly,Patel, Kumar, and Joshi (2016) applied hypsometric analysis in the Tapi River Basin to understand its geomorphic development, concluding that the basin was in a mature stage with moderate erosion.

Despite these advancements, the Barakar River Basin has received limited attention in scientific literature. Previous studies have largely focused on the Damodar River as a whole, neglecting the individual contributions and characteristics of its tributaries, particularly the Barakar. The few existing studies on the Barakar have primarily concentrated on water quality and sediment load (Mukherjee & Saha, 2013), leaving a significant gap in understanding its geomorphological status and erosion dynamics. This lack of detailed morphometric and hypsometric analysis underscores the need for further research.

While morphometric and hypsometric analyses have been applied to various river systems globally, the Barakar River Basin remains understudied, especially in terms of its geomorphological and erosional status. Existing research has primarily focused on broader hydrological assessments, but the specific geomorphic evolution and morphometric characteristics of the Barakar remain largely unexplored. This study aims to fill this gap by applying high-resolution DEM data and GIS techniques to derive crucial geomorphological parameters. By doing so, it provides a comprehensive understanding of the Barakar River Basin’s developmental stage and erosion potential, offering valuable insights for basin management and regional planning.

The primary objective of this research is to conduct a comprehensive geomorphological assessment of the Barakar River Basin through hypsometric and morphometric analyses using high-resolution DEM data.

For the comprehensive geomorphological analysis of the Barakar River Basin, high-resolution digital elevation data (DEM) was necessary to accurately capture the intricate details of the terrain and its hydrological features. The methodology (Figure 2) employed in this study consisted of several key stages, starting with data acquisition and progressing to the derivation of essential geomorphometric properties. In the data acquisition phase, the ALOS PALSAR DEM with a resolution of 12.5 meters was chosen due to its capability to provide highly detailed topographic information, which is critical for capturing the subtle variations in landscape features (Rosenqvist, Milne, Lucas, Imhoff, & Dobson, 2007). This dataset was obtained from the Alaska Satellite Facility (ASF) DAAC, which offers open and free access to ALOS PALSAR data. The fine resolution of the DEM was instrumental in representing the terrain more accurately, thereby facilitating an in-depth and detailed study of the basin's geomorphological and hydrological characteristics.

Once the DEM was acquired, several GIS-based processing and spatial analyses were conducted using ArcGIS Pro 3.0.1 and its advanced spatial tools:

The hypsometric analysis of the Barakar River Basin, as depicted in the provided table (Table 3), allows for an in-depth understanding of the geomorphological evolution of the basin. Hypsometric Integral (H.I.), relative area (a/A), and relative height (h/H) are important parameters to assess the erosional stage of a basin, reflecting how much of the land surface remains elevated relative to its original elevation. The hypsometric analysis of the Barakar River Basin reveals its geomorphological maturity, with elevation ranging from 36.01 m to

Figure 9

1,319 m. The variation in elevation across bands, from 36.99 m to 475.99 m, indicates significant relief changes, particularly at higher elevations, reflecting increased terrain ruggedness (Strahler, 1952).

The total basin area (Table 4) of 7,077 km² is predominantly distributed in mid-elevation zones, as seen between 241.01 m and 283.00 m, a typical feature of semi-mature to mature basins. The relative area (a/A) decreases with elevation, highlighting an advanced erosional stage where minimal area remains at higher altitudes (Keller & Pinter, 2002). The mean elevation across bands ranges from 84.01 m to 1,081.01 m, with a consistent hypsometric integral (H.I.) of 0.50, reflecting a uniform erosion process. The H.I. indicates that 50% of the basin’s original volume has been eroded, signaling a balanced denudation and deposition state (Strahler, 1952). Relative height (h/H) increases from 0.07 at lower elevations to 1.00 at the highest, with significant height distributed in the upper elevations, pointing to steep valleys and uneroded portions of the landscape (Schumm, 1956).

The overall relief of 1,282.9 m suggests substantial erosional activity, particularly in the lower and mid-elevation zones, with remnants of the original topography preserved at higher elevations. This mature stage of development provides insights into future geomorphological trends (Strahler, 1952).

1 H.I. = Mean Elevation-Minimum Elevation  Maximum Elevation-Minimum Elevtion 

The hypsometric curve shown in the figure (Figure 9) highlights the relationship between the relative height (h/H) and the relative area (a/A) of the Barakar River Basin, with a Hypsometric Integral (H.I.) we get by implementing eqn(1) as value of 0.50. This indicates that the basin is in a mature stage of geomorphological evolution, where approximately 50% of the original landmass volume has been eroded. The steep curve at the upper part of the graph, where (h/H) is closer to 1, suggests that a small portion of the basin occupies higher elevations, typically associated with steep slopes and preserved topography. As the curve flattens toward the lower values of (a/A), it implies that much of the basin is composed of mid to lower elevations, which have undergone significant erosion. The overall shape of the curve, with a sharp drop followed by a gradual slope, is characteristic of a basin transitioning from a youthful to a mature stage, with minimal area remaining at the highest elevations. This reinforces the inference that the Barakar River Basin has experienced extensive fluvial erosion, leaving steep residuals at higher elevations while most of the landscape has been reduced to lower levels. Such insights are critical in understanding the long-term evolution of the basin and the dominant erosional processes shaping its terrain (Keller & Pinter, 2002).

The stream order analysis of the Barakar River Basin, as depicted in the table, shows significant insights into the drainage characteristics. The basin comprises a total of 1,712 streams, with the first-order streams being the most numerous (1,336), which gradually decrease as the stream order increases. This follows the typical pattern in river systems, where higher-order streams are fewer in number.

The total length of all streams in the basin is 4,290.44 km, and the average stream length increases with the stream order, indicating the progression of stream lengths as the drainage network becomes more organized. The mean stream length (Lsm) ranges from 1.60 km for first-order streams to 262.85 km for the fifth-order stream, showing an expected correlation between stream length and order.

The stream length ratio (RL), which measures the ratio of the stream lengths between successive orders, ranges from 4.22 to 15.00. This variability suggests that stream lengths increase at different rates between the orders, possibly due to variations in topography or geological influences within the basin. The high RL between the fourth and fifth orders is noteworthy, as it points to significant changes in stream length in the higher orders.

The bifurcation ratio (Rb), which represents the ratio between the number of streams in successive orders, averages 7.10. The individual Rb values range from

4.22 to 15.00, with higher values suggesting greater structural control or rugged terrain, common in areas with complex drainage networks. This high bifurcation ratio implies that the Barakar River Basin experiences strong geological or topographical influences, which impact its stream network's development and organization.

In conclusion, the stream order and bifurcation ratio analysis of the Barakar River Basin highlight the basin's organized but complex drainage structure, influenced by both topography and geology, making it an example of a structurally controlled river system.

The Bhagirathi Basin (Table 4), covering an area of 7077 square kilometers, represents a large drainage system, which has a notable impact on water flow dynamics and sediment deposition. The basin length of 188.01 kilometers suggests the river extends over a considerable distance, influencing its discharge patterns and sediment transport capacity. With a basin perimeter of 686.38 kilometers, the basin boundary is highly irregular, affecting how runoff converges towards the river channels.

The basin relief of 1.28 kilometers indicates a moderate elevation difference between the highest and lowest points, contributing to the potential energy available for erosion and the movement of water and sediment through the basin. The mean bifurcation ratio (7.10) is relatively high, suggesting the presence of a structurally controlled drainage network, with less branching between stream orders and potentially steep slopes.

A relief ratio of 0.01 suggests a gentle slope across the basin, implying slower runoff, which could allow more infiltration, reduce soil erosion, and promote groundwater recharge. The drainage density (0.61 km/sq.km) is moderately low, indicating that the basin has fewer stream channels relative to its size, likely due to infiltration-dominated processes or impermeable bedrock. The stream frequency (0.24 streams/sq.km) supports this, showing that the number of streams is low for the area, which could influence flood response times during heavy rainfall events.

The form factor (0.20) and elongation ratio (0.51) suggest that the basin is elongated, contributing to a prolonged peak flow during storms, rather than rapid, short-duration floods. Similarly, the circularity ratio (0.19) further supports the elongated nature, indicating a shape that delays the time of concentration of runoff. Finally, the constant of channel maintenance (1.65 km) reflects the amount of area needed to sustain one kilometer of stream channel. This moderate value implies that the basin has a balanced interaction between its surface area and the stream network, reflecting moderate permeability and runoff generation.

These morphometric characteristics suggest that the Bhagirathi Basin is characterized by a combination of moderate relief, a structurally controlled drainage network, and slower runoff, which has implications for its hydrological behavior, sediment transport, and flood potential.

The hypsometric and morphometric analysis of the Barakar River Basin provides a detailed view of its geomorphological evolution and structural dynamics. The hypsometric integral (H.I.) of 0.50 suggests a mature stage of erosion, where about 50% of the original volume has been worn away, indicating balanced denudation and deposition processes. The steep hypsometric curve at higher elevations reflects preserved topography in the upper reaches, while the flatter curve at lower elevations indicates significant erosion, typical of semi-mature basins. This pattern reveals how the basin’s landscape has evolved, with most of the area concentrated in mid-elevation zones, signifying advanced erosion stages.

Morphometric parameters such as a high bifurcation ratio (7.10) and low drainage density (0.61 km/km²) highlight the structural control of the drainage system, with elongated basin characteristics delaying runoff concentration. The variability in stream length ratios, particularly the increase in higher stream orders, points to complex topographic influences on stream development. These factors suggest that the Barakar River Basin is largely shaped by geological structures and rugged terrain, with slower runoff and moderate sediment transport.

Together, these analyses present a comprehensive understanding of the basin's mature geomorphology, helping predict future erosion patterns and water flow dynamics.