APPENDIX A 



DESCRIPTION OF RANGE LINES AND BENCH MARKS 

 TORREY PINES BEACH, CALIFORNIA 



INTRODUCTION 



Three range lines normal to the shoreline were established on 

 Torrey Pines Beach for use in making repeated measurements of sand level 

 change in the onshore-offshore direction. Each range line was marked with 

 two bench marks (BM) that define the direction of the range line and 

 elevation of two fixed points relative to a datum. The three range lines 

 are referred to as South Range, Indian Canyon Range, and North Range to 

 designate their geographic position relative to Indian Canyon. 



RANGE LINE LOCATION SURVEY 



The closest Government bench mark to the section of Torrey Pines 

 Beach under study is the U.S. Coast and Geodetic Survey (USCGS) Bench Mark 

 "Ball" located in the NW 1/4 of Section 12, Township 15 South Range 4 

 West from the San Bernardino meridian and base line. The bench mark is 

 a brass disc identified as a USCGS monument at the top of the sea cliff 

 about 1/2 mile south of South Range which designates a point 326.3 feet 

 above mean sea level. This brass disc served as the point of origin for 

 the range line location survey (Figure A-l) . Since the USCGS bench mark 

 is located at the top of the sea cliff, the range line location survey 

 was necessarily performed in two segments that were tied together using 

 a specialized type of surveying technique. The first segment was a 

 level line survey from USCGS "Ball" to an established point at the top 

 of the sea cliff on South Range. This was done using a transit, tape, 

 and rod for measuring elevation and horizontal distance to ±0.01 foot. 

 Figure A-2 shows the plan of the first survey segment with the location 

 of transit station, rod station, and measured lines as listed in Table 

 A-l. 



This survey segment resulted in the location of four points lying 

 on South Range as shown in Figure A-2. These points are: 



a. "+" chiseled in the concrete base of the U.S. Navy 

 southwest range marker. 



b. A 1/2-inch-diameter stainless steel pipe at the top of the 

 sea cliff. 



c. Two 1/2-inch-diameter stainless steel pipes approximately 

 50 feet apart at the foot of the sea cliff. 



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