Radial Flow to an Unconfined Aquifer From Mays, 2011, Ground and Surface Water Hydrology

Example From Mays, 2011, Ground and Surface Water Hydrology A well penetrates an unconfined aquifer. Prior to pumping, the water level (head) is h o = 25 m. After a long period of pumping at a constant rate of 0.05 m 3 /s, the drawdowns at distances of 50 and 150 m from the well were observed to be 3 and 1.2 m, respectively. Compute the hydraulic conductivity of the aquifer and the radius of influence of the pumping well. What type of deposit is the aquifer material. Compute the drawdown at the well for r w =0.5 m

Test 1 Review Chapter 1, Hydrologic cycle and the water balance Basic quantification of hydrologic process such as – Precipitation – Streamflow – Volume and area relationships

Groundwater Learning objectives Be able to quantify the properties of water held in and flowing through the subsurface (soil and rock). The properties of interest include – porosity, – moisture content, – pressure, – suction, – hydraulic conductivity Mays Chapter 2

Macroscopic and microscopic concepts of a porous medium. (from Freeze and Cherry, 1979)

Storage Coefficient for (a) confined and (b) unconfined aquifers From Mays, 2011, Ground and Surface Water Hydrology

Constant Head Permeameter From Mays, 2011, Ground and Surface Water Hydrology

Anisotropy 10 m 4.4 m 6.2 m K=11.6 m/day K=4.5 m/day K=2.2 m/day

Unconfined aquifer between two rivers From Mays, 2011, Ground and Surface Water Hydrology

Radial flow to a confined aquifer From Mays, 2011, Ground and Surface Water Hydrology

Radial Flow to an Unconfined Aquifer From Mays, 2011, Ground and Surface Water Hydrology

AB