In addition, the total volume of water discharged during a flood tends to be larger for urban streams than for rural streams. For example, streamflow in Mercer Creek, an urban stream in western Washington, increases earlier and more rapidly, has a higher peak discharge and volume during the storm on February 1, , and decreases more rapidly than in Newaukum Creek, a nearby rural stream.
As with any comparison between streams, the differences in streamflow cannot be attributed solely to land use, but may also reflect differences in geology, topography, basin size and shape, and storm patterns. The hydrologic effects of urban development often are greatest in small stream basins where, prior to development, much of the precipitation falling on the basin would have become subsurface flow, recharging aquifers or discharging to the stream network further downstream.
Moreover, urban development can completely transform the landscape in a small stream basin, unlike in larger river basins where areas with natural vegetation and soil are likely to be retained. As a result, the water is at a higher stage as it flows past the obstruction, creating a backwater that will inundate a larger area upstream. Sediment and debris carried by floodwaters can further constrict a channel and increase flooding. This hazard is greatest upstream of culverts, bridges, or other places where debris collects.
Small stream channels can be filled with sediment or become clogged with debris, because of undersized culverts, for example. This creates a closed basin with no outlet for runoff.
Although channels can be engineered to convey floodwater and debris quickly downstream, the local benefits of this approach must be balanced against the possibility of increased flooding downstream. Erosion in urban streams represents another consequence of urban development.
Frequent flooding in urban streams increases channel and bank erosion. Where channels have been straightened and vegetation has been removed from channel banks, streamflow velocities will increase, allowing a stream to transport more sediment. In many urban areas, stream-bank erosion represents an ongoing threat to roads, bridges, and other structures that is difficult to control even by hardening stream banks.
Typically, the annual maximum discharge in a stream will increase as urban development occurs, although the increase is sometimes masked by substantial year-to-year variation in storms, as is apparent in the annual maximum discharge for Mercer Creek from to In comparison, the annual maximum discharge for rural Newaukum Creek varied during the period but showed no clear trend. The effects of development in urban basins are most pronounced for moderate storms following dry periods.
For larger storms during wet periods, the soil in rural basins becomes saturated and additional rainfall or snowmelt runs off much as it does in an urban basin. The effect of urban development in the last half of the 20th century on small floods is evident in Salt Creek, Illinois.
Nonetheless, even a small increase in the peak discharge of a large flood can increase flood damages. The frequency of moderate flooding can increase substantially after development. Source: Kevin D. Richards, U. Geological Survey. There are many approaches for reducing flood hazards in basins under development. Areas identified as flood-prone have been used for parks and playgrounds that can tolerate occasional flooding. Buildings and bridges have been elevated, protected with floodwalls and levees, or designed to withstand temporary inundation.
Drainage systems have been expanded to increase their capacity for detaining and conveying high streamflows; for example, by using rooftops and parking lots to store water. Techniques that promote infiltration and storage of water in the soil column, such as infiltration trenches, permeable pavements, soil amendments, and reducing impermeable surfaces have also been incorporated into new and existing residential and commercial developments to reduce runoff from these areas.
Wet-season runoff from a neighborhood in Seattle, Washington, was reduced by 98 percent by reducing the width of the street and incorporating vegetated swales and native plants in the street right-of-way. Tsunamis Where is a tsunami most likely to happen? Can Singapore be affected by a tsunami? Can animals sense an impending tsunami? What should we do during a tsunami? Why do trees seem to resist more to tsunamis than houses?
Why does a boat at sea experience a tsunami differently from a boat near the shore? Volcanoes All About Volcanoes What is the difference between magma and lava? Is lava always liquid? What does a magma chamber look like? What are the largest eruptions in the world? Are earthquakes and volcanic eruptions related? Where can we find volcanoes on earth? Miscellaneous Miscellaneous Why are there mass extinctions? How did life appear on earth? How does photosynthesis work? What is GPS? What is gravity?
What is the big bang? How do we know the age of the earth? The result from this research proves that urbanization has worsened urban flooding to a great extent. With the cumulated damage from continuous urbanization, the severity of urban flooding is expected to increase. In the end, it is worth noting that such promising results also come with affordable computation times. As detailed flood modeling may take days to run in large areas, the simplified models used in this research only takes as little as four hours for the flash flood modeling and 20 min for the floodplain mapping for an area of km 2.
Impervious surface are mainly artificial structures that are covered by impenetrable materials such as asphalt, concrete, brick, and stone. Hydraulic roughness is the measure of the amount of frictional resistance water experiences when passing over land and channel features, which closely relates to land use types. Google Scholar. Anderson DG Effects of urban development on floods in northern Virginia. US Government Printing Office.
Nat Hazards Earth Syst Sci — Article Google Scholar. Proc Econ Finance — Booth DB Urbanization and the natural drainage system—impacts, solutions, and prognoses. River Res Appl — Water Sci Technol — Cronshey R Urban hydrology for small watersheds. US Dept. Dingman SL Physical hydrology. Waveland Press. Texas Water Development Board. Res J Recent Sci — In: Fluvial processes in instrumented watersheds.
Hollis G The effect of urbanization on floods of different recurrence interval. Water Resour Res — Nat Hazards — Kellershohn D Reducing flood risk in Toronto.
Institute for Catastrophoc Loss Reduction Forum. Curr World Environ Kinosita T, Sonda T Change of runoff due to urbanization. In Publication of: Airport Forum. Survey Open-File Rept Proc Technol — Prosdocimi I, Kjeldsen T, Miller J Detection and attribution of urbanization effect on flood extremes using nonstationary flood-frequency models.
Adv Water Resour — State Government of Victoria, Melbourne. Landscape Urban Plan — Yu D, Lane SN a Urban fluvial flood modelling using a two-dimensional diffusion-wave treatment, part 1: mesh resolution effects. Hydrol Process Int J — Yu D, Lane SN b Urban fluvial flood modelling using a two-dimensional diffusion-wave treatment, part 2: development of a sub-grid-scale treatment.
J Land Use Sci — Zhang Y, Guindon B, Sun K Spatial-temporal-thematic assimilation of Landsat-based and archived historical information for measuring urbanization processes. J Hydrometeorol — Download references. You can also search for this author in PubMed Google Scholar. Correspondence to Boyu Feng.
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.
Reprints and Permissions. Feng, B. Urbanization impacts on flood risks based on urban growth data and coupled flood models. Nat Hazards , — Download citation. Received : 29 January Accepted : 15 December Published : 29 January Issue Date : March Anyone you share the following link with will be able to read this content:. Sorry, a shareable link is not currently available for this article.
Provided by the Springer Nature SharedIt content-sharing initiative. Skip to main content. Search SpringerLink Search. Download PDF. Abstract Urbanization increases regional impervious surface area, which generally reduces hydrologic response time and therefore increases flood risk. Introduction During urbanization, rain water movement and storage at ground surface within a local watershed are significantly altered by the changes in landscape from natural to man-made Booth Full size image.
GTA Land use land cover maps from to Flowchart of hydrologic and hydraulic models. Surface runoff rate curves for four selected sub-basins under various urbanization conditions. River hydrographs for six selected junctions under various urbanization conditions. Discussions Results from HEC-HMS Near-linear relations between the surface runoff rate and impervious surface percentage can be found for the four selected sub-basins in Sect 4.
Table 1 Linear regression parameters Full size table. Table 2 River hydrograph peak value Full size table. Table 3 Flood-influenced areas and maximum water depths Full size table. Conclusions This research provides experiments on the impact of urbanization on urban flooding, which assists the understanding of this specific factor in urban flooding.
Notes 1. View author publications. Ethics declarations Conflict of interest There is no conflict of interest that we know of for this work. Additional information Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
About this article. Cite this article Feng, B.
0コメント