Loading in 5 sec....

Groundwater pumping to remediate groundwater pollutionPowerPoint Presentation

Groundwater pumping to remediate groundwater pollution

- By
**netis** - Follow User

- 93 Views
- Uploaded on

Download Presentation
## PowerPoint Slideshow about ' Groundwater pumping to remediate groundwater pollution' - netis

**An Image/Link below is provided (as is) to download presentation**

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript

### Groundwater pumping to remediate groundwater pollution

March 5, 2002

TOC

- 1) Squares
- 2) FieldTrip: McClellan
- 3) Finite Element Modeling

First: Squares

- Oxford Dictionary says
- “a geometric figure with four equal sites and four right angles”

Squares

- Units within a flow net are curvilinear figures…
- In certain cases, squares will be formed
- Constant head boundary…

Flownet

- No flow crosses the boundary of a flowline !
- If interval between equipotential lines and interval between flowlines is constant, then volume of water within each curvilinear unit is the same…

Flow nets (rules)

- Flowlines are perpendicular to equipotential lines
- One way to assume that Q’s are equal is to construct the flownet with curvilinear squares
- Streamlines are perpendicular to constant head boundaries
- Equipotential lines are perpendicular to no-flow boundaries

Flow nets (rules 2)

- In heterogeneous soil, the tangent law is satisfied at the boundary
- If flow net is drawn such that squares exist in one part of the formation, squares also exist in areas with the same K

a1

K1

K2

a2

How to determine the spacing of wells?

- Determine feasible flow rates
- Determine range of influence
- Determine required decrease of water table
- Calculate well spacings

Confined Aquifer

- Well discharge under steady state can be determined using

Unconfined Aquifer

- Well discharge under steady state can be determined using

Unconfined Aquifer

- Well discharge under steady state WITH surface recharge can be determined using

What is optimal well design ?

- In homogeneous soil:

In heterogeneous situation:

- Wells have flow rate between 1 and 100 gpm
- Some wells are in clay, others in sand

Finite Difference method

- Change the derivative into a finite difference D

Approach to numerical solutions

- 1) Subdivide the flow region into finite blocks or subregions (discretization) such that different K values can be assigned to each block and the differentials can be converted to finite differences

Approach to numerical solutions

- 2) Write the flow equation in algebraic form (using finite difference or finite elements) for each node or block

Approach to numerical solutions

- 3) Use “numerical methods” to solve the resulting ‘n’ equations in ‘n’ unknowns for h subject to boundary and initial conditions

1-D example

- Boundaries: h left = 10, h right = 3
- Initial conditions h = 0
- K is homogeneous = 3
- Delta x = 2

Download Presentation

Connecting to Server..