Table 1.4. Erosion and Accretion Rates from Historical Monitoring of Shorelines of the 
Galveston Bay System. 
Bay Locations 
1850-52 to 1930 
1930 to 1982 
1850-52 to 1982 
No. of 
Rate 
No. of 
Rate 
No. of 
Rate 
stations 
(ft/yr) 
stations 
(ft/yr) 
stations 
(ft/yr) 
Trinity Bay 
66 
-1.8 
60 
0.9 
60 
-0.7 
E. Trinity Bay 
Lake Anahuac 
26 
-3.0 
25 
-1.8 
25 
-2.6 
(does not include Trinity delta) 9 
-2.9 
6 
+0.6 
e 
-0.9 
Trinity Delta 
10 
+3.9 
9 
+7.2 
9 
+5.8 
W. Trinity Bay 
21 
-2.6 
20 
-2.3 
20 
-2.3 
Galveston Bay 
57 
-2.2 
55 
-4.2 
55 
-3.0 
West Bay 
106 
-1.6 
98 
-2.4 
84 
-2.0 
N. West Bay 
23 
-2.5 
7 
-3.8 
7 
-3.6 
Chocolate Bay 
15 
-1.0 
15 
-2.4 
15 
-1.6 
W. West Bay 
4 
-6.5 
7 
-6.3 
4 
-7.0 
W. peripherals 
30 
-1.3 
29 
-1.5 
27 
-1.6 
S. West Bay 
34 
-0.8 
40 
-2.1 
31 
-1.5 
East Bay 
54 
-1.8 
48 
-3.2 
47 
-2.1 
S. East Bay 
30 
-2.1 
24 
-3.7 
23 
-2.3 
N. East Bay 
24 
-1.4 
24 
-2.8 
24 
-1.9 
Gulf Locations 
1883 to 1930 
1930 to 1955 
1883 to 1974 
No. of 
Rate 
No. of 
Rate 
No. of 
Rate 
stations 
(ft/yr) 
stations 
(ft/yr) 
stations 
(ft/yr) 
Bolivar Peninsula 
16 
-0.3 
19 
+4.1 
16 
0.1 
1850 to 1930 
1930 to 
1956 
1838 to 
1970 
No. of 
Rate 
No. of 
Rate 
No. of 
Rate 
stations 
(ft/yr) 
stations 
(ft/yr) 
stations 
(ft/yr) 
Galveston Island 
28 
-3.3 
28 
+45 
28 
-2.4 
Source: Paine and Morton, 1986 (17) and Morton, 1974 and 1975 (18). 
high rates of shoreline accretion adjacent to Bolivar Roads, as much as 28 feet per year on Bolivar 
Peninsula and 48 feet per year on eastern Galveston Island, were not included in Table 4; coastal 
engineering structures (e.g., jetties) artificially enhance accretion rates. Similarly, maximum losses of 
land measured in the bays occur in areas of maximum man-induced subsidence. 
Rates of erosion and accretion for the Galveston Bay System were calculated from historical 
monitoring of shorelines for long time periods. Although effects of hurricanes are averaged into these 
calculations, the magnitude of work accomplished by a hurricane is not apparent. Since 1900, four 
hurricanes have centered on Galveston, in 1900,1947,1959 and 1983 (11). The unnamed 1900 storm 
was the most severe (10)—having an approach speed of 10 mph, maximum winds of 125 mph, 
barometric pressure of 27.64 inches, and a storm surge height of 20 feet. No maps or aerial photo¬ 
graphs are available to document erosion and accretion for that storm. However, Carla in 1961 had 
nearly the same intensity in all categories. A gulfward facing shoreline eroded as much as 800 feet 
and about 500 feet of sand accreted to the rear shore of the barrier island (20). No bay shoreline 
measurements were found. 
19 
