|Survey Monument Maintenance|
|By Brenda Hemstead|
|June 14, 2011|
Surveying relies on physical reference objects placed in the ground. While temporary stakes are what the public may see most often in conjunction with construction work, the enduring reference marks (usually called monuments) are much less prominent. Monuments serve to mark points used for geodetic control networks as well as points used to reference property boundaries. Monuments can take a variety of forms.
The location of a monument may be recorded directly on a map, and nearby objects may also be documented to aid in finding (“recovering”) a monument at a later date. A map showing a monument with distances and directions to surrounding objects is called a “tie sheet”. Photographs may be used to further assist in recovering a monument, and mapping coordinates (even if of low accuracy) may be provided so that a GPS receiver can be used to navigate to the vicinity.
A monument may be labeled with the name of the organization that set it and other useful identifying information. A more visible nearby post (“witness post”) may also be labeled.
Location of monuments
A surveyor may or may not have flexibility in where to place a monument. For a property corner (including the PLSS), there is usually only one choice. For geodetic control, on the other hand, the location is chosen to meet practical concerns about line of sight, spacing between nearby monuments, and/or ease of access.
The value of control information or boundary marking is jeopardized by any disturbance to a monument, so protection is key. Disturbing a federalsurvey marker is a misdemeanor and carries a $250 fine for deliberate tampering. Missing or disturbed geodetic control markers, as well as those in danger of being disturbed, should be reported to the agency stamped on the cap or by filling out an online station condition report form. The county surveyor or land information office is the best place to begin when reporting a problem with a PLSS monument.
Note: uninformed attempts to restore a disturbed monument can be extremely counterproductive. If a geodetic control monument is disturbed, yet evidence of that disturbance is concealed, users of the monument will not know that its published position and/or elevation are no longer correct. Similarly, a property boundary monument that has been moved will provide a false impression of correct location.