BYU Groundwater Modeling Exercise

 Agricultural Drains

Drains are sometimes used in agricultural regions with high water tables. Drains are thought to create a healthier environment for plant growth and to dry the soil so that it can be accessed by farm equipment throughout the crop production cycle. Drainage can also reduce saline-alkaline problems.

One type of agricultural drain is a simple trench as shown below. The drain acts as a fixed head boundary.

Build a MAGNET model to simulate the lowering of the water table at a farm as a result of two parallel agricultural drains constructed as trenches. The problem details are shown in the following figure. We will assume that the fields and drain continue to the north and south and we will assume parallel flow boundaries at the north and south ends.

Also solve the problem analytically and compare the results from the two different approaches.

MAGNET/Modeling Hints: 

• Use the ‘Distance Display’ capabilities when editing geometric features and/or the ‘Ruler’ tool to properly represent distances between model features.
• Use all relevant information from the provided schematic in your analysis.
• Represent the drains as constant head line features.