Environmental Engineering Reference
In-Depth Information
points to a system; for example, manholes in water or wastewater systems
may provide access to sewer lines or vaults containing on/off or pressure-
reducing water valves. Because many utilities run under other infrastructure
(roads, building), manholes also provide potential access points to critical
infrastructure as well as water and wastewater assets. In addition, because
the portion of the system to which manholes provide entry is primarily
located underground, access to a system through a manhole increases the
chances that an intruder will not be seen; therefore, protecting manholes can
be a critical component of guarding an entire community.
The various methods for protecting manholes are designed to prevent
unauthorized personnel from physically accessing the manhole or to detect
attempts at unauthorized access to the manhole. A manhole intrusion sensor
is a physical security device designed to detect unauthorized access to the
utility through a manhole. Monitoring a manhole that provides access to a
water or wastewater system can mitigate two distinct types of threats. First,
monitoring a manhole may detect access of unauthorized personnel to water
or wastewater systems or assets through the manhole. Second, monitoring
manholes may also allow the detection of the introduction of hazardous sub-
stances into the water system. Several different technologies have been used
for manhole intrusion sensors, including mechanical systems, magnetic sys-
tems, and fiberoptic and infrared sensors. Some of these intrusion sensors
have been specifically designed for manholes, while others consist of stan-
dard, off-the-shelf intrusion sensors that have been implemented in a system
specifically designed for application in a manhole.
Manhole Locks
A manhole lock is a physical security device designed to delay unauthorized
access to the utility through a manhole. Locking a manhole that provides
access to a water or wastewater system can mitigate two distinct types of
threats. First, locking a manhole may delay access of unauthorized person-
nel to water or wastewater systems through the manhole. Second, locking
manholes may also prevent the introduction of hazardous substances into
the wastewater or stormwater system.
Radiation Detection Equipment for Monitoring Personnel and Packages
A major potential threat that water and wastewater facilities face is contami-
nation by radioactive substances. Radioactive substances brought on-site at a
facility could be used to contaminate the facility, thereby preventing workers
from safely entering the facility to perform necessary water treatment tasks.
In addition, radioactive substances brought on-site at a water treatment plant
could be discharged into the water source or the distribution system, contami-
nating the downstream water supply; therefore, detection of radioactive sub-
stances being brought on-site can be an important security enhancement.
