Upgrading Security - The Drinking Water - page 287

In a second example, Washington State's “Drinking Water Tech Tips:
Sanitary Protection of Reservoirs” document states that vents must be pro-
tected to prevent the water supply from being contaminated. The document
indicates that non-corrodible No. 4 mesh may be used to screen vents on
elevated tanks. The document continues to state that the vent opening for
storage facilities located underground or at ground level should be 24 to 36
inches above the roof or ground and that it must be protected with a No.
24 inch mesh non-corrodible screen. New Mexico's administrative Code
also specifies that vents must be covered with No. 24 mesh (NMAC Title 20,
Chapter 7 , Subpart I, 208.E). Washington and New Mexico, as well as many
other municipalities, require vents to be screened using a non-corrodible
mesh to minimize the entry of insects, other animals, and rainborne con-
tamination into the vents. When selecting the appropriate mesh size, it is
important to identify the smallest mesh size that meets both the strength
and durability requirements for that application.
Visual Surveillance Monitoring
Visual surveillance is used to detect threats through continuous observation
of important or vulnerable areas of an asset. The observations can also be
recorded for later review or use (e.g., in court proceedings). Visual surveil-
lance system can be used to monitor various parts of collection, distribution,
or treatment systems, including the perimeter of a facility, outlying pump-
ing stations, or entry or access points into specific buildings. These systems
are also useful in recording individuals who enter or leave a facility, thereby
helping to identify unauthorized access. Images can be transmitted live to a
monitoring station, where they can be monitored in real time, or they can be
recorded and reviewed later. Many facilities have found that a combination
of electronic surveillance and security guards provides an effective means
of facility security. Visual surveillance is provided through a closed-circuit
television (CCTV) system, in which the capture, transmission, and reception
of an image is localized within a closed circuit. This is different than other
broadcast images, such as over-the-air television, which is broadcast over the
air to any receiver within range. At a minimum, a CCTV system consists of
• One or more cameras
• A monitor for viewing the images
• A system for transmitting the images from the camera to the monitor.
Water Monitoring Devices
Earlier it was pointed out that proper security preparation really comes
down to a three-legged approach: detect , delay , respond . The first leg of secu-
rity—detect—is discussed in this section; specifically, this section deals with