How does soil type affect lag time?

Soil type – clay soils do not drain easily and become saturated very quickly. This results in rapid overland flow and shorter lag times. Dry soils slow down water transfer leading to longer lag times. Slope – steep slopes lead to rapid water transfer and shorter lag times.

What factors affect lag time?

How does soil type affect discharge?

How does land use affect lag time?

Does vegetation increase lag time?

How does rock type affect a hydrograph?

If the rock type within the river basin is impermeable surface runoff will be higher, throughflow and infiltration will also be reduced meaning a reduction in lag time and an increase in peak discharge. If a drainage basin has a significant amount of vegetation this will have a significant affect on a storm hydrograph.

What affects lag time geography?

Factors influencing lag time include: Size of drainage basin. Vegetation. Valley side steepness. Soil type.

How does rock type affect a storm hydrograph?

If the rock type within the river basin is impermeable surface runoff will be higher, throughflow and infiltration will also be reduced meaning a reduction in lag time and an increase in peak discharge. If a drainage basin has a significant amount of vegetation this will have a significant affect on a storm hydrograph.

How physical and human factors affect the flood risk?

Human factors increasing flood risk: urbanisation , because towns and cities have more impermeable surfaces. deforestation , because removing trees reduces the amount of water intercepted and increases run-off.

How is a unit hydrograph used?

Unit hydrographs are used to estimate flood hydrographs by multiplying each ordinate of unit hydrograph by the volume of runoff. The unit hydrograph theory is based on the principle of proportionality, such that discharge varies directly with runoff depth.

What is lag time hydrograph?

Lag time – the time taken between peak rainfall and peak discharge. Rising limb – shows the increase in discharge on a hydrograph.

How does rock type and soils affect stores of water in a drainage basin?

Drainage basins characterised by impermeable rock and soils tend to have higher drainage density due to the lack of infiltration and percolation. This means that water enters a channel quickly, leading to an increase in discharge.

How does soil type affect river discharge?

Soil type – clay soils do not drain easily and become saturated very quickly. This results in rapid overland flow and shorter lag times. Dry soils slow down water transfer leading to longer lag times. Slope – steep slopes lead to rapid water transfer and shorter lag times.

How do you find direct runoff volume?

The first step is to compute the total volume of direct runoff. To do this, add all direct runoff values, and multiply the sum of all the direct runoff flows by the time interval (in seconds) of the series as shown below. (convert cubic feet per second to cubic feet of volume).

How does rock type affect river discharge?

– Type of rock (impermeable or permeable) – Impermeable rock will not allow water to seep in, thus causing larger amounts of surface runoff and a shorter lag time. – The gradient of the drainage basin – Steep gradients will cause greater overland flow and a shorter lag time.

What factor is the largest influence in how water drains in a watershed?

Precipitation: The greatest factor controlling streamflow, by far, is the amount of precipitation that falls in the watershed as rain or snow. However, not all precipitation that falls in a watershed flows out, and a stream will often continue to flow where there is no direct runoff from recent precipitation.