SUMMARY OF LAND LOSSES IN TEXAS 



In this century alone land losses along the Texas gulf shoreline have amounted to 

 nnore than 4,000 ha (10,000 acres) and average rates of loss have increased from about 14 

 ha (35 acresVyr near the turn of the century to nearly 160 ha (400 acres)/yr over the past 

 decade (Morton 1977). Accelerating land losses of substantially greater magnitude 

 (10,000 ha/yr) have also been reported for the Louisiana coast (Gogliano et al. 1981). The 

 magnitude of land loss in Texas is illustrated in Figure 2 which shows nearly 320 m of 

 beach retreat with erosion rates averaging between 7 and 8 m/yr. Although land losses in 

 the bays and lagoons have not been quantified in detail, they probably represent 

 additional losses of about 120 ha (300 acres)/yr. These high rates of land loss have led to 

 the emplacement of numerous breakwaters, jetties, groins, bulkheads, and seawalls in on 

 attempt to hold back the sea or at least delay the retreat of the shoreline. 

 Unfortunately these structures have not always accomplished their intended purposes and 

 in some instances they have actually caused increased beach erosion.^ 



Bays and Lagoons 



Shorelines bordering the bays and lagoons are typically low clay bluffs, wetland 

 marshes, or sand and shell beaches. Each shoreline type formed under different 

 geological conditions and each responds differently to present-day processes. 



The clay bluffs are composed principally of Pleistocene fluvial-deltaic sediments 

 that form the upland areas of the adjacent Coastal Plain. Of the three shoreline types, 

 clay bluffs exhibit the greatest disequilibrium with extant coastal processes and, 

 therefore, are the most vulnerable to wave attack and undercutting. As a result, 

 essentially all clay bluffs are retreating at rates up to 7 m/yr. 



Coastal marshes that fringe the bays of the upper Texas coast are decreasing in 

 area not only because of shoreline erosion, but also because of sediment compaction and 

 attendant submergence. These wetland losses caused by sediment compaction are fewer 

 in Texas when compared to Louisiana owing to the smaller area of delta-plain and bay- 

 margin marshes where this process occurs. The loss of wetlands in Texas is primarily a 

 function of shoreline retreat which averages 3 to 5 m/yr in many areas. By comparison, 

 sand and shell beaches are relatively stable although their rate oif retreat is commonly on 

 the order of to 2 m/yr. 



Gulf Shoreline 



In contrast to historical changes in the bay shorelines that are complex (McGowen 

 and Brewton 1975; White et al. 1978), changes in the Texas gulf shoreline are fairly 

 systematic and beach erosion is most severe in three areas (Figure I): between Sabine 

 Pass and Rollover Pass, between San Luis Pass and Brown Cedar Cut (vicinity of the 

 Brazos River delta. Figure 2), and on South Padre Island (vicinity of the Rio Grande 

 delta). Each of these areas is characterized by thin sand beaches that are retreating 

 over marsh and delta-plain muds at average rates of 3 to 5 m/yr regardless of storm 

 frequency and intensity. In each of these areas, ocean waves have consumed hundreds of 

 acres and have destroyed numerous beach houses in the past 20 years. Despite the 

 hazards of storm overwash, flooding, and shoreline erosion, permanent residence and 

 recreational development continues to increase in these areas and structural methods are 

 being used in an attempt to reduce land losses and to provide storm protection. 



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