Groundwater overview
CE 473/573 Fall 2007
Lecture 1
Hydrology & Geology
Hydrologic cycle
Aquifers in the U.S.
Aquifers in Iowa
Aquifers in Iowa
Water Supply
USGS monitoring wells
Measuring conductivity
Borehole permeameter
Transmissivity in Iowa
Well and cone of depression
Well recommendations
Well recommendations
Pumping affects streamflow
Mechanism of subsidence
Subsidence in the U.S.
Subsidence example: CA
Saltwater intrusion
Contaminants
Nonpoint source pollution
Drainage from agriculture
Arsenic in groundwater
Leaky underground storage tanks
Contaminants
benzene, toluene, ethylbenzene, and xylenes (BTEX)
methyl tert-butyl ether (MTBE)
LUSTs in Boulder CO
Otis Air Force Base
“The Plume”
Yucca Mountain, NV
Yucca Mountain, NV
…colloidal groundwater migration must
have played an important role in
transporting the plutonium. Models that
either predict limited transport or do not
allow for colloid-facilitated transport may
thus significantly underestimate the extent
of radionuclide migration. (Kersting et al.
1999)
Groundwater models
Groundwater model
Modflow example
Further applications
Des Moines Water Works supply
Infiltration gallery
Radial collector wells
Source: DM Water Works
Des Moines Water Works supply
Des Moines Water Works supply
Does denitrification occur in the soil? Does the water “short circuit”?
Source: DM Water Works
Wetlands
Loss of wetlands area: 89% (Iowa), 53% (U.S.)
Wetlands
Legislation aims for “no net loss” of wetlands, but who has authority?
Appeals Court: hydrologic
connections between the site and
navigable waters
Stevens: include groundwater
with a significant nexus of
connection to more distant
navigable waters
Scalia: Stevens’s definition of
wetlands is “beyond parody”
Ethanol production
From the DM Register:
[The executive director of the Iowa Renewable Fuels Association]
said water used by ethanol facilities is "a drop in the bucket“
compared with the total groundwater usage in the state.
More than half of the water used by ethanol plants evaporates during
production or is treated and released back into streams. That,
essentially, continues the natural cycle of water, [he] said.
Ethanol production
http://www.desmoinesregister.com/graphics/07june/EthanolFlash.swf