STATUS OF SAND BY-PASSING PLANT AT 

 SALINA CRUZ HARBOR, ISTHMUS OF TEHUANTEPEC, MEXICO 



Details of the Salina Cruz stationary by-passing plant 

 were presented in two previous Beach Erosion Board Bulletins. 

 An article in the July 19& Bulletin described the completed 

 installation and pointed out the difficulties in creating a 

 natural flow of sand into the reaches of the suction lines 

 of the pumps. An article in the April 1952 Bulletin reviewed 

 the functional aspects of the installation, including some 

 characteristics of the beach in the vicinity of the harbor. 

 The 1952 article pointed out that creating a natural flow of 

 sand to the pump intake had not been satisfactorily accomplish- 

 ed as of that date. 



The report herein covers the general progress of the Salina Cruz 

 by-passing plant since 19£2, as outlined in a September 195& letter received 

 from the Director, Mexican Free Ports. Figure 1 shows the Port of 

 Salina Cruz, which is located on the Pacific Coast of Southern Mexico, 

 The Port is divided into an inner and outer harbor with the by-passing 

 plant located adjacent to the west breakwater of the outer harbor. 

 The basic intent of operation of the by-passing plant was to intercept 

 the eastward drifting sand and pump it through a discharge line extend- 

 ing over the loading docks and a swing span separating the two harbors, 

 thence, to the shore east of the east breakwater. The intakes for the 

 pumps were located landward of the high water line and attempts were 

 made to create a movement of sand to the suction lines by means of a 

 dragline and other equipment. These attempts to feed the sand to the 

 point of pump intake, with the intention of causing recession of the 

 shore line, have been discontinued since the procedure has proven to be 

 inefficient and very costly. Another factor which caused the temporary 

 discontinuation of the sand by -passing operation was the frequent 

 interruption of pumping necessary for opening the discharge pipe swing 

 span to allow all types of craft to enter or leave the inner harbor. 

 This resulted in a negligible quantity of sand being by-passed. 



Since the discontinuation of operations, the harbor has shoaled 

 at a more rapid rate. At the beginning of 195U it was necessary to use 

 two hopper dredges, the "Presidente Aleman" and the "Coatzacoalocs" in 

 order to maintain the harbor. 



A program has been undertaken to reduce shoaling in the harbor and 

 reactivate the by»-passing plant. The program consists of building a 

 rubble mound groin normal to the beach (as indicated in Figure l), 

 about 2,000 feet west of the dredge installation. The present length 

 of the groin is about 260 feet, and its final length will be approximately 

 560 feet. The purpose of this groin is to reduce the supply of sand 



