35.2. Difference Between Porosity, Specific Yield, and Specific Retention

Try these first

1. 1.

   Define porosity in your own words.

   Hint

   Think about how much space exists between particles.

2. 2.

   What does specific yield measure?

   Hint

   Consider what happens when water drains out through gravity.

3. 3.

   What does porosity measure?

   • Total void space
   • Water yield
   • Water retention

   Hint

   Think about the space available for water storage.

4. 4.

   True or False: Specific yield is the same as porosity.

   • True
   • False

   Hint

   Recall the definitions of both terms.

5. 5.

   An aquifer has a porosity of 0.35, and its particles are mainly composed of fine sand that retains a significant amount of water through adhesion. Analyze what this means for both specific yield and specific retention.

   Hint

   Consider what 'fine sand' characteristics indicate about its ability to yield water.

6. 6.

   If you have an aquifer with a porosity of 0.40 and you find through experimentation that it has a specific retention of 0.10, how would you evaluate its potential for sustainable yield, discussing possible scenarios?

   Hint

   Think about how much water is available and needed to maintain the ecosystem.