by the US. Army Corps of Engineers. The dredging wastes were considered
partially polluted with industrial and domestic wastes in 11 of these harbors.
Scheduled operations called for dumping into the open
waters of the lake
322,000 cubic yards of polluted wastes—enough to cover one city block to a
40—foot depth. Another 2,330,000 cubic yards of polluted material would be
dumped in conned areas as part of a new program
to limit dredging pollu—
tion. Some 1.8 million cubic yards of unpolluted dredging wastes also were
_
scheduled for dumping into the open lake. The ecological consequences of
'
such dredging projects are unclear, but polluted wastes have been shown to
have serious effects in dredging disposal sites off New York City (this will be
discussed elsewhere).
Another problem is that decreasing industrial discharges into Lake Mich—
igan does not mean that the wastes will disappear. Some waste material is
now dumped into landlls which, if poorly designed, allow heavily con—
taminated liquids to leak out into surface waters. Reliance on deep wells for
In an effort to ease the lake's burden of industrial waste, another form of diversion
has been used: Some waste material is dumped into landfills Which, if poorly designed, allow contaminated liquids to leak out into surface waters. Other waste materials are iniected into deep wells which may pollute ground water. Deep wells
have problems of their own.
Problems of deep-well disposal of liquid waste:
l. lmproper pressure monitoring, resulting in failure of iniection equipment or fracturing of disposal formation.
2. Mining, excavations, or additional wells might lower subsurface pressures. This
could trigger escape of waste fluids from the disposal zone (into other formations, water reservoirs, or to the surface).
3. Wastes under pressure can escape through abandoned and improperly plugged
oil, gas, or water wells nearby.
4. Corrosion of well with age, allowing fluids under pressure to escape.
5. Natural or induced fractures in rock formations through which wastes may escape.
6. Corroded or broken casing through which wastes can escape.
7. Corrosion break in injection tubing, allowing wastes to enter space between
tubing and casing (annulus).
8. Poor cement iob. Wastes under pressure can break out between outer casing
and the surrounding geological formation if outer casing is not adequately cemented ta formation.9. Leaking or faulty packer, allowing wastes to enter annulus.
10. Several wastes iniected together can react and form new compuunds. Wastes
can also react with the iniection formation, or with other wastes iniected into
nearby wells which share the same disposal area. Such reactions could create
toxic fluids or poisonous gases in some cases.
il. Fluid could invade iniection zone by means of osmosis, with resulting rise in
pressure and fracturing of zone.
12. Clogging of injection tubing or disposal formation can cause pressures to rise
abruptly,
with consequent possibility of rupturing of tubing or fracturing of formation and consequent escape of wastes.
l 3. Wastes
under pressure can reduce friction between rocks under stress, trigger—
lng earthquakes.
24
Assault on a Lake
partially polluted with industrial and domestic wastes in 11 of these harbors.
Scheduled operations called for dumping into the open
waters of the lake
322,000 cubic yards of polluted wastes—enough to cover one city block to a
40—foot depth. Another 2,330,000 cubic yards of polluted material would be
dumped in conned areas as part of a new program
to limit dredging pollu—
tion. Some 1.8 million cubic yards of unpolluted dredging wastes also were
_
scheduled for dumping into the open lake. The ecological consequences of
'
such dredging projects are unclear, but polluted wastes have been shown to
have serious effects in dredging disposal sites off New York City (this will be
discussed elsewhere).
Another problem is that decreasing industrial discharges into Lake Mich—
igan does not mean that the wastes will disappear. Some waste material is
now dumped into landlls which, if poorly designed, allow heavily con—
taminated liquids to leak out into surface waters. Reliance on deep wells for
In an effort to ease the lake's burden of industrial waste, another form of diversion
has been used: Some waste material is dumped into landfills Which, if poorly designed, allow contaminated liquids to leak out into surface waters. Other waste materials are iniected into deep wells which may pollute ground water. Deep wells
have problems of their own.
Problems of deep-well disposal of liquid waste:
l. lmproper pressure monitoring, resulting in failure of iniection equipment or fracturing of disposal formation.
2. Mining, excavations, or additional wells might lower subsurface pressures. This
could trigger escape of waste fluids from the disposal zone (into other formations, water reservoirs, or to the surface).
3. Wastes under pressure can escape through abandoned and improperly plugged
oil, gas, or water wells nearby.
4. Corrosion of well with age, allowing fluids under pressure to escape.
5. Natural or induced fractures in rock formations through which wastes may escape.
6. Corroded or broken casing through which wastes can escape.
7. Corrosion break in injection tubing, allowing wastes to enter space between
tubing and casing (annulus).
8. Poor cement iob. Wastes under pressure can break out between outer casing
and the surrounding geological formation if outer casing is not adequately cemented ta formation.9. Leaking or faulty packer, allowing wastes to enter annulus.
10. Several wastes iniected together can react and form new compuunds. Wastes
can also react with the iniection formation, or with other wastes iniected into
nearby wells which share the same disposal area. Such reactions could create
toxic fluids or poisonous gases in some cases.
il. Fluid could invade iniection zone by means of osmosis, with resulting rise in
pressure and fracturing of zone.
12. Clogging of injection tubing or disposal formation can cause pressures to rise
abruptly,
with consequent possibility of rupturing of tubing or fracturing of formation and consequent escape of wastes.
l 3. Wastes
under pressure can reduce friction between rocks under stress, trigger—
lng earthquakes.
24
Assault on a Lake