Hydrology Newsletter

"A flood is an overflow of water on normally dry ground". This is most commonly due to an overflowing river, a dam break, snow-melt, or heavy rainfall. Tsunamis, storm surge, or coastal flooding are some of the examples of common flooding whereas instances of extreme flooding includes the flood  in 1931 at China which killed between 2,000,000 and 4,000,000 people.In 2002, Texas flood which was caused by a reservoir overflow. In just three days, the floodwaters carved canyons measuring 1.4 mile (2.2 kilometres) long and  20-foot-(6 meters)-deep. Floods can be measured for height, peak discharge, area inundated, and volume of flow. Due to the ability of this extreme event to cause disasters, it is important to predict the event well in advance or at the time of designing flood control structures.Flood is a result of a discharge;generally peak discharge;which the drainage network can not hold and eventually overflows and causes inundation.  There are various methods to estim...

The principal objective of hydrologic models is to forecast the runoff of a surface water body, especially dendritic systems like rivers, streams, etc. The inputs to these models are generally Rainfall/Precipitation, Soil Characteristics, and other Climatic parameters like evapotranspiration, humidity, etc. LULC and geo-morphology are also used as the required input parameters of the hydrologic models. Both input and output of these models are temporally as well as spatially variable. Now the resolution varies with different models. Some models consider all the sub-basins to be a single watershed and determine the output based on the characteristics of this single watershed(lumped).In contrast, some other models will consider the {impact|effect} of each of the sub-basins on the central outflow of the watershed(distributed).In a few models, the entire watershed is divided into grids or units of uniform dimension. However, the accuracy is highest for the models, which considers the {impa...