University : James Cook University UniLearnO is not sponsored or endorsed by this college or university.
Subject Code : EA2006
Country : Australia
Assignment Task:

Water-table

In some aquifers groundwater occurs under unconfined conditions. In this case the water-table is the boundary between the zones of aeration and saturation. The potentiometric surface is generally defined as the surface to which water in an aquifer would rise by hydrostatic pressure. Where the water-table intersects the land surface, springs, seeps, streams and lakes are formed. The position of the water-table can be determined by measuring the depth to water in a well tapping an unconfined aquifer. 

Water-level contour maps (potentiometric maps)

A potentiometric map represents a subsurface contour map showing the elevation of a potentiometric surface of an aquifer. The water-table can be mapped in a manner similar to contouring surface topography. Water elevation readings are measured in metres above sea level or another datum level and are taken in wells, springs, lakes or streams. Water-table elevations of the same value are then drawn as water-level contours. Most commonly the water table forms a gently sloping surface that follows the land surface (i.e. higher under hills than adjacent valleys). By using water-level maps in conjunction with topographic maps, the depth to the water table can be determined. 

Hydraulic gradient

The hydraulic gradient (I) is the difference in water level per unit of distance in a given direction. It can be measured directly from water-level maps in metre per metre (dimensionless). 

Flow lines

The direction of groundwater flow is generally indicated by flow lines, which are drawn perpendicular to water-level contours.

Groundwater divide

Groundwaters flowing into different directions are separated by a groundwater divide (Figure a). Water on one side will flow into a different direction to water on the other side.

Groundwater flow regime

Questions for Figure 1: Show clearly your calculation steps for each question.

  1. What is the hydraulic gradient (dh/dl) along the groundwater flow line in the western quadrant? (2 marks)

  2. If the hydraulic conductivity of the aquifer is 10-2 cm/sec and its specific yield is 15 percent, what is the groundwater velocity, in centimetres per second, in the vicinity of the flow line in the western quadrant?

  3. What is the groundwater velocity, in meters per day, in the vicinity of the flow line in the western quadrant?

  4. If the aquifer is 10 metres thick and has a porosity of 20 percent (a typical value for a poorly sorted sandy aquifer), how much water, in cubic metres, is stored in an area of 1 km2.

  5. Construct a flow line on the map from site A. Look at the direction of groundwater flow from Site A. If petrol would be spilled at site A, would it discharge into the ocean or into the river? Explain your answer.

 

This EA2006: Engineering Assignment has been solved by our Engineering Experts at UniLearnO. Our Assignment Writing Experts are efficient to provide a fresh solution to this question. We are serving more than 10000+ Students in Australia, UK & US by helping them to score HD in their academics. Our Experts are well trained to follow all marking rubrics & referencing style.

Be it a used or new solution, the quality of the work submitted by our assignment experts remains unhampered. You may continue to expect the same or even better quality with the used and new assignment solution files respectively. There’s one thing to be noticed that you could choose one between the two and acquire an HD either way. You could choose a new assignment solution file to get yourself an exclusive, plagiarism (with free Turnitin file), expert quality assignment or order an old solution file that was considered worthy of the highest distinction.

  • Uploaded By : Alex Cerry
  • Posted on : May 06th, 2019
  • Downloads : 341

Whatsapp Tap to ChatGet instant assistance