monument so that its location can be reestablished by swinging arcs from any 

 two of the points. When an existing control point is not nearby, auxiliary con- 

 trol points should be established near the profile after the elevation of the 

 monument is determined. If the monument is temporarily assigned an assumed ele- 

 vation, the auxiliary control points should be established using the same assumed 

 datum. When the actual elevation of the monument is determined, all the assumed 

 elevations can be corrected. 



Poststorm photos of coastal areas show that telephone poles, piles, and 

 similar objects stay in place through storms very well, due to their shape and 

 good foundations, making them excellent reference points. Examples of such ob- 

 jects that may be found near a beach are (1) power, phone and light poles; (2) 

 pier and boardwalk piles; (3) house piles; (4) stubby pile-type road barricades; 

 and (5) fire hydrants. Other good references include objects not likely to be 

 affected by storms, such as manhole cover seats, concrete abutments or curbs, 

 and corners of buildings or foundations. For long-term projects, consideration 

 must be given to the potential stability of cultural features. For example, 

 over the course of several years a road may be repaved or widened, an addition 

 added to a house, or a boardwalk improved. 



When using a reference point as a position reference, the actual spot on 

 the object should be clearly defined in the documentation and marked with 

 paint. An elevation reference can be provided by using the tops of short piles, 

 spikes in phone poles, or another solid, defined location on a reference point. 

 It must be noted, though, that placing spikes or nails in phone or power poles 

 creates a potentially dangerous condition for linemen using climbing spikes 

 and is illegal in some states, such as Pennsylvania. If no stable references 

 are available in the vicinity of the monument, additional monuments must be 

 set to serve as reference points. These monuments should be placed even far- 

 ther landward than the base line to ensure that they are in a stable location 

 and allow for the reestablishment of the base line if lost. To provide addi- 

 tional permanence, consideration should be given to extending each of the pro- 

 file lines landward to include a very stable section. This stable section 

 would be surveyed for only a few of the profile lines during each periodic sur- 

 vey, but frequently enough to detect long-term changes. This infrequent survey 

 of the landward extension of each profile line will provide additional data in 

 the event of major beach changes, as well as for future comparison. 



b. Referencing to Grid System . Even though a base line may be established 

 for only a short-term study, consideration must be given to referencing the base 

 line to some type of control system, such as a state or national grid system or 

 geodetic coordinates, to provide some degree of permanency. The cost of such a 

 referencing program, which has been reduced significantly with the advent of 

 electronic distance measuring equipment, must be weighed against the value of 

 the need to reoccupy the profiles in 10 or 20 years or after a particularly 

 severe storm. This decision need not be made at the start of a study; if the 

 data produced are judged to be valuable for future comparison, the base line 

 can be permanently referenced later during the study. This allows the option 

 of maximizing the long-term use of good data or minimizing the cost of refer- 

 encing and documenting a study subsequently found to have been poorly conducted 

 or to have produced results of questionable value. If funding limitations will 

 not allow referencing to a grid system, the study should be brought to the atten- 

 tion of appropriate State or Federal agencies in the event that they would want 

 to provide more permanent reference for their own future use. 



