infrastruktura: Flood

Evidence: 48 • authority: 72

Streamflow, or channel runoff, is the flow of water in streams and other channels, and is a major element of the water cycle. It is one runoff component, the movement of water from the land to waterbodies, the other component being surface runoff. Water flowing in channels comes from surface runoff from adjacent hillslopes, from groundwater flow out of the ground, and from water discharged from pipes. The discharge of water flowing in a channel is measured using stream gauges or can be estimated by the Manning equation. The record of flow over time is called a hydrograph. Flooding occurs when the volume of water exceeds the capacity of the channel.

Evidence: 55 • authority: 92

Global estimation of bankfull river discharge reveals distinct flood recurrences across climate zones.. Bankfull discharge, the maximum flow a river can convey before spilling over its banks, is central to modelling flood risk and understanding river-channel evolution. Global flood inundation models assume a 2-year return period for bankfull conditions, but this assumption remains untested globally. Here we use observations and machine learning to estimate bankfull discharge at ~1-km resolution along a recently developed global river network. We show that the widely used 2-year discharge reasonably approximates bankfull-flow magnitude, but bankfull return periods vary substantially within a…

Evidence: 52 • authority: 88

100 Years of Competition between Reduction in Channel Capacity and Streamflow during Floods in the Guadalquivir River (Southern Spain). Reduction in channel capacity can trigger an increase in flood hazard over time. It represents a geomorphic driver that competes against its hydrologic counterpart where streamflow decreases. We show that this situation arose in the Guadalquivir River (Southern Spain) after impoundment. We identify the physical parameters that raised flood hazard in the period 1997–2013 with respect to past years 1910–1996 and quantify their effects by accounting for temporal trends in both streamflow and channel capacity. First, we collect historical hydrological data to l…

Evidence: 52 • authority: 72

A flood is an overflow of water (or rarely other fluids) that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are of significant concern in agriculture, civil engineering and public health. Human changes to the environment often increase the intensity and frequency of flooding. Examples for human changes are land use changes such as deforestation and removal of wetlands, changes in waterway course or flood controls such as with levees. Global environmental issues also influence causes of floods, namely climate change which causes an intensification of the water cycle and sea level rise. For example, climate…

Evidence: 48 • authority: 92

River channel change can affect flood hazard and impact substantially.. More than one billion people are exposed to flood risk globally, with this number projected to double by 2050. Global flood models underpin risk assessment and adaptation planning, yet typically assume that river bankfull capacity corresponds to a fixed two-year return period, neglecting spatial and temporal variability in channel characteristics. Here, we evaluate how inundated areas and population exposures respond when forced with empirically-derived bankfull capacities in the Mississippi basin using the Fathom Global Flood Model. We find that present-day bankfull flows generally correspond to return periods of less…

Evidence: 45 • authority: 72

On the morning of 26 August 2026, a series of flash floods and debris flows destroyed the Gyirong Port on the China–Nepal border and struck dozens of settlements along a 72 km (45 mi) stretch of the Trishuli River in Nepal. These events are also known as the 2026 Nepal-China floods, Bhotekoshi flood, or Rasuwa flood. At least 1,454 deaths and 5,285 missing persons in Nepal, and 43 deaths and 519 missing in the Tibet Autonomous Region of China were reported. The flood carried the bodies of some victims 250 km (160 mi) away into neighbouring India. The precipitating geological event, initially reported as a glacier collapse in the Langtang region of the Himalayas, caused a chain reaction whos…

Evidence: 41 • authority: 80

Time-focused investigation of river channel morphological changes due to extreme floods

Evidence: 41 • authority: 72

A floodplain or flood plain or bottomlands is an area of land adjacent to a river that stretches from the banks of the river channel to the base of the enclosing valley and experiences flooding during periods of high discharge. The soils usually consist of clays, silts, sands, and gravels deposited during floods. Because of regular flooding, floodplains frequently have high soil fertility since nutrients are deposited with the flood waters. This can encourage farming; some important agricultural regions, such as the Nile and Mississippi river basins, heavily exploit floodplains. Agricultural and urban regions have developed near or on floodplains to take advantage of the rich soil and fresh…

Evidence: 41 • authority: 92

Flood frequency analysis of Panchganga river basin using Gumbel and Log-Pearson Type III models.. Floods are among the most frequent and destructive hydro-climatic hazards worldwide, causing severe damage to human life, infrastructure, and natural ecosystems. Flood Frequency Analysis (FFA) is a basic hydrologic analysis technique that estimates peak flood discharges and associated return periods, which are useful for an evidence-based understanding of flood risk and for flood mitigation planning. This study analyzed the Panchganga river basin in Maharashtra, India, known for recurring severe flood events due to intense monsoon rainfall and sediment-induced changes in river morphology. The a…

Evidence: — • authority: 72

A levee ( or ), is an elevated ridge alongside the banks of a river, often intended to protect against flooding of the area adjoining the river. Alternatively, it is called a dike (American English), dyke (Commonwealth English), floodbank, or stop bank. It is a type of embankment. A levee, natural or artificial, is usually earthen and often runs parallel to the course of a river in its floodplain or along low-lying coastlines. Naturally occurring levees form on river floodplains following flooding. Sediment and alluvium are deposited on the banks and settle, forming a ridge that increases the river channel's capacity. The levee's shape is due to the coarser load of the river immediately dep…

Evidence: — • authority: 72

A meander cutoff is a natural form of a cutting or cut in a river which occurs when a pronounced meander (hook) in a river is breached by a flow that connects the two closest parts of the hook to form a new channel, a full loop. The steeper drop in gradient (slope) causes the river flow gradually to abandon the meander which will silt up with sediment from deposition. Cutoffs are a natural part of the evolution of a meandering river. Rivers form meanders as they flow laterally downstream (see sinuosity).

Evidence: — • authority: 72

A meander is one of a series of regular sinuous curves in the channel of a stream. It is produced as a watercourse erodes the sediments of an outer, concave bank (cut bank or river cliff) and deposits sediments on an inner, convex bank which is typically a point bar. The result of this coupled erosion and sedimentation is the formation of a sinuous course as the channel migrates back and forth across the axis of a floodplain. The zone within which a meandering stream periodically shifts its channel is known as a meander belt. It typically ranges from 15 to 18 times the width of the channel. Over time, meanders migrate downstream, sometimes in such a short time as to create civil engineering…