Rivers are dynamic systems shaped by gravity, draining precipitation from their source to their mouth. They form networks of tributaries, distributaries, drainage basins, and watersheds, playing a central role in shaping landscapes and human settlements.

Drainage systems describe the pattern of river networks shaped by slope, structure, and geology. They are broadly classified into sequent drainage systems, which follow the land slope, and insequent systems, which develop without regard to structure or slope.

Insequent drainage systems are river systems that do not follow the normal land slope but cut across geological structures. They are classified into antecedent (inconsequent) and superimposed systems. Drainage patterns, on the other hand, describe the geometric arrangements of rivers and tributaries in a basin, such as dendritic, trellised, rectangular, radial, centripetal, annular, parallel, barbed, and pinnate.

Rivers pass through three distinct stages in their course – youth, mature, and old. Each stage is characterized by dominant erosion types, landforms created, and the river’s interaction with its slope, velocity, and sediment load.

River erosion operates through mechanical, chemical, and hydraulic processes that shape valleys and landscapes over time. These processes create distinct landforms such as valleys, gorges, canyons, waterfalls, rapids, potholes, plunge pools, terraces, and meanders. With increasing river maturity, these features evolve and provide insights into geomorphological history.

Ox-bow lakes are crescent-shaped lakes formed when a river abandons its meander loop. River rejuvenation occurs when rivers regain erosive power due to a fall in sea level or uplift of land, leading to renewed vertical erosion and terrace formation.

Rivers transport eroded material through traction, saltation, suspension, and solution. When the river loses energy, it deposits these sediments, forming distinctive landforms such as alluvial fans, cones, flood plains, levees, point bars, deltas, and braided channels.

Deltas are depositional landforms formed at the mouths of rivers when sediment accumulates faster than it can be removed by tides, currents, or waves. Based on shape and formation processes, deltas can be classified into arcuate, bird-foot, estuarine, and cuspate types.

River deltas are depositional landforms formed at the mouths of rivers where sediment accumulates faster than it is removed. They vary in shape and structure due to the interaction of fluvial and marine processes. Common types include arcuate, bird-foot, estuarine, and cuspate deltas.

Glaciers are large, moving masses of ice and debris that flow due to gravity and pressure. They move faster at the center and slower at the sides and bottom. Glacial erosion occurs mainly through plucking and abrasion, shaping unique landforms in highlands and depositing sediments in lowlands.

Glaciers carve landscapes through powerful processes of plucking and abrasion. Erosional landforms such as cirques, arêtes, pyramidal peaks, horns, roche moutonnee, and crag-and-tail structures are characteristic features of glaciated regions.

As glaciers erode, transport, and deposit material, they transform pre-existing landscapes. Valleys once shaped by rivers become U-shaped troughs. Tributary glaciers form hanging valleys, depressions become ribbon lakes and rock basins, uneven erosion leads to rock steps, coastal glacial valleys form fjords, and the snout marks the dynamic front of the glacier.

When glaciers melt, they leave behind sediments ranging from fine clay to large boulders. These deposits form distinct landforms like moraines, drumlins, eskers, kettle lakes, kames, and outwash plains, which provide valuable insights into past glaciations.

Wind in arid and semi-arid regions erodes land through abrasion, deflation, and attrition. This produces distinct landforms such as blow-outs, inselbergs, mushroom rocks, zeugens, yardangs, ventifacts, demoiselles, and wind bridges/windows. These features reveal the intensity and direction of past wind activity.

Wind transports material through suspension, saltation, and creep, and deposits them when speed decreases or obstacles are encountered. This creates depositional landforms like ripple marks, sand dunes (various types), and loess plains.

In deserts and semi-arid regions, running water (though limited) shapes landforms. Flash floods, wadis, badlands, mesas, buttes, playas, bolsons, pediments, and bajadas reflect the combined action of water and aridity.

Groundwater not only stores and supplies fresh water but also shapes landscapes. Its chemical and mechanical actions lead to the development of unique landforms like caves, stalactites, stalagmites, sinkholes, and karst topography.

Wells are man-made structures dug to access groundwater. They may be permanent or intermittent depending on their depth and water table level. Artesian wells, on the other hand, allow water to rise to the surface automatically due to hydraulic pressure in confined aquifers.

Springs are natural outlets of groundwater emerging at the surface. They form due to geological structures such as permeable and impermeable rock layers, faults, volcanic activity, or karst landscapes. Springs can be cold, hot, perennial, intermittent, or even geysers.

Karst topography refers to unique landforms found in limestone and dolomite regions, shaped primarily by groundwater dissolution. It includes caves, sinkholes, dolines, and underground drainage systems. The term 'Karst' originates from the Karst region of former Yugoslavia.

Karst erosional landforms are created by the chemical weathering and solutional action of groundwater on limestone and dolomite regions. These include depressions (sinkholes, dolines, uvalas, poljes), surface features (lapies, terra rossa), underground features (caves, ponors), and transitional forms like natural bridges.

Karst depositional landforms are created inside limestone caves due to precipitation of calcium carbonate from dripping groundwater. They include stalactites (roof deposits), stalagmites (floor deposits), and columns (when both join). Collectively, such cave formations are called speleothems.

Seawater acts as a powerful geomorphic agent through waves, tides, and currents. Waves mainly cause erosion and deposition, tides aid deposition, and currents transport sediments. The interaction of these processes shapes coasts, shorelines, and coastal landforms.

Coastlines are classified based on tectonic, erosional, depositional, and sea-level change processes. They include coastlines of submergence, emergence, neutral, compound, and faulted types, each with distinct geomorphic characteristics.