![]() As a result of these differences, high tide flooding that reaches the threshold in one city might only cause a minor inconvenience for a few people, while waters that reach the threshold in another city might flood large sections of a low-lying downtown area. Every city is unique in terms of land cover, topography, where roads and other infrastructure are located (how close to sea level), and the presence of flood defenses such as seawalls. However, these flood thresholds do not necessarily correspond to a specific level of observed disruption or damage. This method is useful because it allows scientists to calculate a flood threshold for any location along the coast, as long as enough years of data have been collected. 3įlood thresholds for this indicator are defined based on a statistical approach that accounts for typical local fluctuations in the tides. 2 Coastal flooding can also affect human health-for example, by increasing the risk that drinking water and wastewater infrastructure will fail, putting people at risk of being exposed to pathogens and harmful chemicals. These impacts are of particular concern because more than 40 percent of Americans live near the coast, and more than $1 trillion of property and structures is at risk. Recurrent coastal flooding can cause impacts such as frequent road closures, reduced stormwater drainage capacity, and deterioration of infrastructure not designed to withstand frequent inundation or exposure to salt water. When water rises above this level, minor impacts from flooding typically occur in some streets, many storm drains become ineffective, and a coastal flood advisory may be issued. Many coastal cities have defined “nuisance” flooding (also referred to as high tide flooding) thresholds. This type of tidal flooding is expected to increase in depth, frequency, and extent in the United States during this century. ![]() Floods are happening more often as rising sea level reduces the gap between average sea level and the height of the land. In recent years, however, coastal cities are increasingly flooding on days with less extreme tides or little wind, even on sunny days. Flooding typically occurs during seasonal high tides (“king tides”) and storms that push water toward the shore. As relative sea level rises due to climate change (see the Sea Level indicator), one of the most noticeable consequences is an increase in coastal flooding. “Relative sea level change” refers to the height of the ocean relative to the land at a particular location. Higher sea level also makes coastal infrastructure more vulnerable to damage from storms. Rising sea level inundates low-lying wetlands and dry land, erodes shorelines, contributes to coastal flooding, and increases the flow of salt water into estuaries and nearby groundwater aquifers. Changing sea levels are affecting human activities in coastal areas.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |