ENCE 489G/621, Mid-Term #1

1. The following figure is the result of a particle size distribution analysis from 8 natural soils. From the curves please suggest the two most porous and two least porous soils. Clearly discuss your rationales.
   
2. What are the major factors that may affect the solution enhancement of permeability in carbonate aquifers?
3. A farmer has a well tapping into a local groundwater aquifer in his property. He pumps on average 2.0 x 10³ m³ per year for his farm. All the well water is used for irrigation. The size of the property is 10,000 m² and the local average annual rainfall is 1,000 mm. The precipitation/evapotranspiration ratio of this area is around 0.85.
1. Draw a figure of the hydrologic cycle relevant locally to the farmer's property only.
2. Formulate the hydrologic equation for the farm. Assume no net storage change of the groundwater. Assume there is not outflow from the land surface and soil to any streams.
   
3. What is the amount of irrigation infiltrating back to the aquifer?
   
4. What is the amount of water that the farmer draws from his neighbor's groundwater storage and/or surface streams?
4. Use the following hydrograph to determine the amount of groundwater recharge during the storm. The drainage area is 0.0016 square miles.
   
5. Derive the capillary rise equation for the tube in the following figure. If the contact angle of the glass and water is 5^o, what is the height of the water column in the glass tube? Use a surface tension of 72.7 dynes/cm for water. The desnity of water is 1 g/cm³ and the gravitational acceleration is 980 cm/s². The radius of the lower tube (r₁) is 1.8 mm and that of the upper tube (r₂) is 0.1 mm. The length of the lower tube above the water level (l₁) is 7 mm and that of the upper tube (l₂) is 183 mm.