Jan Edwards, of the Organizing Committee, sent an interesting 2003 study of beach erosion at Surfside. The study is 3 years old, and concludes that the cause of erosion is the moving of the mouth of the Brazos River in 1929.

Severe Beach Erosion at Surfside, Texas
Caused by Engineering Modifications
to the Coast and Rivers

February, 2003,
by Richard L. Watson, Ph.D., Consulting Geologist.

The PDF file is 34 pages, 3.4MB:
http://texascoastgeology.com/papers/surfside.pdf#search='san%20bernard%20river%20mouth'

This study looks primarily north of the existing Brazos River mouth. It says a lot more that seems to ignore the sand at the mouth of the San Bernard.  The study is only three years old though!  The map to the right is from 1975, and shown on page 18 of the study. You can click this one for a larger version.

Following are some quotes from the document:

• "It is very likely that neither Surfside or Quintana would be having an erosion problem today if the Brazos river was still discharging at its original, natural mouth." Page 11

• "The severe beach erosion at both Surfside and Quintana is almost entirely due to man- 5
  made changes in the Brazos River and the coastline. Only man-made changes in the form
  of beach nourishment and/or armoring the shoreline with a sea wall or revetment will
  stop the erosion." Page 32 Conclusion

• "It is well established that there is a severe and accelerating beach erosion problem at Surfside, Texas. While a small part of the erosion may be due to natural causes, such as decreased sand transport to the coast by rivers and global sea level rise, it is obvious, at this location, most of the erosion is caused by man-made changes to the Brazos River and the Freeport Harbor entrance channel. Diversion of the river 7 miles in the downdrift direction has starved the Surfside and Quintana beaches of river sand. Numerous 10 upstream dams and reservoirs on the Brazos river have drastically reduced the amount of sand the river now carries to the coast." Page 1, Executive Summary

• "It has been nearly 75 years since the Brazos River was diverted to the south, and the old Brazos delta has completely eroded away and no longer serves as a nearshore source for sand that waves can bring onshore to nourish the beach.  There is, now, little sand offshore, with only a thin veneer of sand over deltaic mud. Likewise, dunes in the Surfside area are very small and store only a small volume of sand which can be transported offshore during storms to flatten the beach profile and reduce wave attack. If any of that sand is washed offshore onto the clay zone, it will not be transported back to the beach." Page 2 Executive Summary

• "In a study of the effects of changes in the Brazos River on erosion at Sargent Beach, Seelig and Sorenson (1973) estimated that the amount of sand carried to the coast after construction of upstream reservoirs was reduced by two-thirds. Page 16

• "The best solution to provide a beach at Surfside (and to stop further erosion) is to nourish the beaches with beach quality sand from nearby sources." Page 3 Executive Summary

• "...natural causes of beach erosion are dwarfed by man-made changes in the rivers and the longshore sediment transport system along much of the coast. Page 24 Conclusion

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