What effects river discharge?

Destruction of vegetation (deforestation) – Less infiltration + interception causes more surface run off and increases speed of the water. River Management – Presence of dams allow river flow to be controlled, which may cause more discharge (before the dam) , or less (below the dam).

What happens if river discharge increases?

In a natural situation, an increase in discharge (cubic feet/second) will result in an increase in all three parameters – the river becomes wider, deeper and flows at a higher velocity. When a stream channel can no longer accommodate increased discharge it overflows its banks and a flood occurs.

How does discharge affect water quality?

The quantity of streamflow (also called “discharge”) is an important factor in determining water quality and, thus, in interpreting water-quality data. The potential effects of contaminants on drinking-water supplies and aquatic habitats depend largely on the amount of water flowing in streams.

What would be the effects of the changes in the river ecosystem?

More frequent droughts and shifting precipitation patterns lower water levels in rivers, lakes and streams, leaving less water to dilute pollutants. Higher temperatures cause more frequent algal blooms and reduce dissolved oxygen levels, both of which can cause fish kills and do significant harm to ecosystems.

How does vegetation affect river discharge?

Vegetation intercepts precipitation and slows the movement of water into river channels. This increases lag time. Water is also lost due to evaporation and transpiration from the vegetation. This reduces the peak discharge of a river.

How does drainage density affect river discharge?

An elongated basin will produce a lower peak flow and a longer lag time than a rounder basin. Basins with a higher drainage density (number of tributary rivers) collect rain water more quickly, therefore the lag time will be shorter.

Does discharge increase or decrease downstream?

Both width and depth increase downstream because discharge increases downstream. As discharge increases the cross sectional shape will change, with the stream becoming deeper and wider.

What is river discharge?

‘River discharge’ is the volume of water flowing through a river channel; measured at any given point in cubic metres per second.

What are two threats against river ecosystems?

Human activities pose threats to river ecosystems, including placing land from forests, grasslands, and wetlands into urban or agricultural uses, dams, pollutant loadings, alteration of natural drainage characteristics, introduced species, overharvesting, and climate change.

How does climate change affect river flooding?

As warmer temperatures cause more water to evaporate from the land and oceans, changes in the size and frequency of heavy precipitation events may in turn affect the size and frequency of river flooding (see the Heavy Precipitation indicator).

How does discharge affect erosion?

In the lower reaches of a stream, where the discharge is greater, since friction is less the stream need not be so steep to transport the load. If it were steeper than needed to transport the sediments erosion would result. But this would decrease the gradient leading to a decrease in erosion.

How does precipitation affect the discharge of a river?

Heavy storms result in more water entering the drainage basin which results in a higher discharge. The type of precipitation can also have an impact. The lag time is likely to be greater if the precipitation is snow rather than rain. This is because snow takes time to melt before the water enters the river channel.

What are the effects of urbanisation on river discharge?

Areas that have been urbanised result in an increase in the use of impermeable building materials. This means infiltration levels decrease and surface runoff increases. This leads to a short lag time and an increase in peak discharge. Hydrograph – a graph that shows river discharge and rainfall over time.

What is the relationship between Infiltration and discharge in rivers?

This means infiltration levels decrease and surface runoff increases. This leads to a short lag time and an increase in peak discharge. Hydrograph – a graph that shows river discharge and rainfall over time. Flood – when the capacity of a river to transport water is exceeded and water flows over it’s banks.

How does vegetation affect the lag time of a river?

Vegetation intercepts precipitation and slows the movement of water into river channels. This increases lag time. Water is also lost due to evaporation and transpiration from the vegetation. This reduces the peak discharge of a river.