• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Analyse How the Inputs and Outputs from a River Basin Can Vary Over Time

Extracts from this document...

Introduction

Analyse How the Inputs and Outputs from a River Basin Can Vary Over Time Both the inputs to and outputs from a river basin can vary both spatially (in different areas) and temporally (over time), due to daily, seasonal and annual occurrences. Precipitation mainly reaches the grounds surface from the atmosphere as snow and rain. Heavy snow is often intercepted and stored on the tops of hills and mountains and may lead to a decrease in river levels. Some rainfall may fall directly into the stream or river and some may fall onto the land and flow into the river basin through a variety of routes including throughflow, stemflow and overland flow. The intensity and duration of precipitation has a short term but regular effect upon both the inputs and outputs of a river basin due to the weather patterns. Over a short period of time, for example a week, the precipitation levels over the river basin can significantly vary, as on some days of the week the total precipitation can be extremely high and the next it could be virtually zero. ...read more.

Middle

Lithology of river basins can also affect the output of a river as those river valleys which are made up of permeable or porous rocks such as chalk and sandstone allow the water to pass through them into underground water stores for instance aquifers. Limestone also allows water to pass through it into bedding planes and joints. Due to this, areas of the river basin which are made up of this type of rock will have low rates of surface run off and no surface streams due to high rates of infiltration through the rocks and soil, reducing or moderating the input into the river's main channel. Impermeable rocks such as granite however, will not allow any water whatsoever to infiltrate through them and areas of land which contain these rock types in their lithology will be subject to a higher drainage density (surface streams) and a higher level of runoff into the main river channel, decreasing the overall lag period of the river basin and increasing the total output, as well as causing the discharge to fluctuate rapidly over a short period of time and can be therefore more prone to flooding. ...read more.

Conclusion

In the summer, evaporation is more frequent due to the higher temperatures and low levels of humidity and in winter, evaporation rates are very low as the wetter and colder periods decrease the rate of evaporation. Evaporation has also been reduced by man building amenities such as drainage systems where the surface water is channelled underground. As an increased demand for water through industry, homes and expanding populations also contributes to a river basins overall output, fresh water stores, demand by man, global warming and precipitation levels are only a few of the short term effects placed upon the rivers overall output total. Groundwater stores and levels of precipitation are linked to the stream flow, baseflow and throughflow found in a river basin, all of which have a large impact upon the total output of the basin itself. An increase in the levels of groundwater can lead to a decrease in overland flow and the output of the river. The numerous inputs and outputs of a river can vary dramatically over time due to changes in all aspects of life including climate, urbanisation, relief and precipitation levels which fluctuate both diurnally and seasonally. As the weather and atmospheric conditions are now unpredictable, no one can determine how these inputs and outputs will continue to change over time. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Hydrology & Fluvial Geomorphology section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Here's what a teacher thought of this essay

3 star(s)

This is a reasonable answer to what appears to be a simple question but isn't! It is difficult to stick to the question as set. The temptation is to drift on to other factors affecting discharge - which has happened here. Overall the author shows an understanding of the key ideas. The answer would benefit from a clearer explanation at the beginning of the idea of the river basin as a "system" .

Marked by teacher Nigel Fisher 16/02/2012

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Hydrology & Fluvial Geomorphology essays

  1. Marked by a teacher

    Examine the factors influencing the movement of glaciers.

    4 star(s)

    Large parts of the West Antarctic ice sheet are at basal melting point, so there may be large areas underneath where a layer of water exists.

  2. Hydrology and Fluvial geomorphology. (Q&A)

    For your essay I suggest you take each of the factors mentioned in your question and explain how each one may affect the regime of the river. It would be better if you could actually give examples using named rivers.

  1. Explain how human activity can modify the hydrological cycle.

    It means that ice can hold less water, and so this excess water is no longer held as storage, but enters the cycle in oceans and lakes. This water can then evaporate and condense to become precipitation, and so rainfall may increase.

  2. How may knowledge of the hydrological cycle and its components assist in devising flood ...

    Assessing flood peaks can also help making decisions on how much flood space to allow when building artificial levees. Artificial flows can also be created through river engineering and knowledge of the flows and behavior of the river can also help determine the potential negative impacts of the river engineering

  1. Study the downstream changes of Loughton Brook.

    They also change from a high sphericity to a low sphericity. The Hydrological Cycle The hydrological cycle is the constant movement of water through the atmosphere, land and sea. It is continuous and has no starting or ending point. The hydrological cycle runs in all drainage basins.

  2. An investigation into changes in channel parameters down the river Horner

    Gradient Decrease Typically a hill becomes less steep as you go down hill. Velocity Decrease - I think that the gradient decreasing will mean the velocity decreases. Where the river is steeper the water should run faster (due to gravity).

  1. How A River Changes As It goes Downstream.

    The lower course of the river is the final stage where the river widens up as far as it can go and joins the sea. This part is where it is a whole lot wider, deeper, and the channel gradient is nearly flat, compared to when it was steep at the beginning.

  2. Examine how a glacier operates as a system (25)

    Other inputs include the condensation of water vapour from air, which then freezes. Also, the sublimation (the changing of a gas to a solid) of water vapour from the air directly to ice crystals. Bits of rock also form part of the glacier, so when the glacier erodes away the

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work