hydrological processes return to normal levels

Many times, the amount, accuracy and representativeness of the records are not enough to achieve an adequate reliability in results. One example is the increase in impermeable surfaces due to built-up areas, which alter the natural flow of water.Studies about river flows or, in general, hydrological processes are based on available records. The physical character of urban areas can affect the local hydrological cycle. Rainfall strikes the soil directly and compacts it, and the runoff of the rainfall that stays on the surface moves quickly to rivers causing floods. Removing trees can lead to a reduction of interception.

Their forests flourish on relatively thin soils. The Tropics have a fragile natural environment with complex biodiversity. This can lead to rivers drying up in times of low rainfall. Over abstraction is defined as when too much water is abstracted from groundwater reserves. The inputs, outputs, flows and stores of water of a hydrological cycle can also be affected by human impact. Do human impacts affect hydrological processes? The heavy rain from summer thunderstorms can lead to flash flooding as the dry soil surface becomes waterlogged quickly, causing rapid surface runoff. As the ground warms up, evaporation means that the air above heats and rises. it is much drier on the east yet the summer months can experience heavy bursts of rain from conventional air instability. They are particularly prone to orographic and frontal rainfall. I n the west, there are drainage basins which are exposed to the air masses from the Atlantic. Looking at the UK as a case study, we can see three different types of rainfall on the west and the east. When the warm air rises and cools to become condensation, this leads to clouds which then eventually form rain and snow. Precipitation input and hydrological processes Urban areas have impermeability and increase rapid surface runoff, evaporation and interception. Grasslands have higher infiltration, percolation, throughflow and evaporation than arable land. Rural areas permit more natural processes compared to urban areas. Some rocks are impermeable, preventing infiltration and causing surface saturation.Ĭold climates such as snow-capped peaks can hold water until it thaws which can lead to delayed flow. The geology of the basin is also important. Higher vegetation coverage will increase interception and evapotranspiration and decrease surface runoff. Steeper slopes promote faster movement and shorter storage times compared to gentler slopes. The impact of drainage basin factors on hydrological processesĭrainage basin factors like shape, relief, geology, vegetation, climate and land use determine what happens to the precipitation when it falls. Water that has been taken up by plants and transpired onto the leaf surface.īoth the effect of evaporation and transpiration.Ī volume of water passing a certain point in the channel over a certain amount of time. The water flowing in the river channel, also known as discharge and runoff.įlow over the surface when the ground is frozen, saturated or impermeable clay or during an intense storm. Slow-moving water that flows into the river channel. The vertical flow of water between soil and rock layers. Water that seeps laterally through soil below the surface but above the water table. Common when there is slow or steady rainfall. Water held in rocks (also known as aquifer). It is water captured by plants, buildings and hard surfaces.Īny water in surface water such as lakes, ponds and puddles. Temporary storage of water before reaching soil. Main hydrological processes in a drainage basin Surface runoff can flow over impermeable and saturated surfaces until it eventually reaches river channels and becomes streamflow. The percolation of surface water through the rocks underneath to become groundwater, stored in aquifers. Running off the surface as overland flow, also known as surface runoff.Īny pathway taken by the water can be delayed by: Reaching the land surface and then infiltrating the topsoil. When precipitation occurs, the water can follow three pathways: Hydrological processes in a drainage basin Evaporation and evapotranspiration to the atmosphere.ĭrainage basins are also known as catchment areas as they catch the precipitation falling within the watershed.Open systems mean that their inputs are not governed by outputs and more water can be lost than received.

Hydrological processes return to normal levels