TABLE 3-3 



SEA LEVEL RISE SCENARIOS TO THE YEAR 2075 



TABLE 3-4 



NUMBER OF ACRES (PERCENT COVERAGE) FOR PRINCIPAL ZONES UNDER 



VARIOUS SCENARIOS AND DATES 



Zone 



Existing I960 



Basel ine 2075 



Low Scenario 2075 



High Scenario 2075 



TUCKERTON MARSH (TIDAL RANGE = 2.0 FT) 



Hi gh I and 

 Transi t ion 

 High Marsh 

 Low Marsh 

 Tidal Flat 

 Water 



TOTAL 



4,900 

 1,200 

 4,600 

 300 

 10 

 5.400 



(30) 

 (7) 



(28) 

 (2) 



(<■) 



(33) 



16,400 (100) 



5,600 



4,600 



600 



200 



10 



5.400 



(34) 

 (28) 

 CO 

 (i) 

 (<D 

 (33) 



16,400 (100) 



GREAT BAY BOULEVARD MARSH (TIDAL RANGE - 3.18 FT) 



Highland 

 Trans i t ion 

 High Marsh 

 Low Marsh 

 Tidal Flat 

 Water 



TOTAL 



300 

 200 



4,600 

 200 



2,400 

 10.600 



(2) 



( I) 



(25) 



( I) 



( 13) 



(38) 



18,300 ( 100) 



500 

 2,000 

 2,700 

 1,500 

 2,400 

 9.200 



(3) 

 (11) 

 (15) 



(8) 

 (13) 

 (50) 



18,300 (100) 



18,300 ( 100) 



Baseline 2075 and Low Scenario. Under existing trends, the model developed for this 

 study, similar to Charleston, predicts a net increase in substrate elevation under the baseline 

 condition where sedimentation rate exceeds sea level rise. As Tables 34 and 3-5 indicate, the 

 biggest changes would be an increase in the transition zone area in the Tuckerton marsh and 

 creation of more low marsh along Great Bay Boulevard. The percentage of highland would 

 increase significantly with the addition of 900 acres, or 3 percent of the entire study area. 



The low scenario implies a much different change in character of the study area. Under this 

 model, net substrate elevation would decrease by the year 2075, but the change would be 

 relatively small— around 40 cm. A review of Tables 3-4 and 3-5 and of Figures 3-5 and 3-6 shows 

 the major impact would be a replacement of high marsh with comparable areas of low marsh. 

 Overall, the number of acres of transition marsh, high marsh, and low marsh would almost 

 exactly balance out. Most of today's tidal flats in the Great Bay Boulevard marsh subdivision 

 would become inundated and add to the open water area. Higher mean water levels would 

 displace aporoximately 700 acres of highland, killing plant species that cannot tolerate frequent 

 tidal inundation (high-marsh species) but promoting growth of other species that can (low-marsh 

 species). 



Both the baseline and low scenario models represent relatively minor and gradual changes 

 within the New Jersey study area. The net change in overall wetland acreage is insignificant. 

 However, the distribution of each subenvironment will undergo major changes and profoundly 

 affect marsh ecology. Since recent studies place a high probability on the low scenario in the 

 future (Titus et al. 1984), the major trend in New Jersey would be replacement of high marsh with 

 low marsh. Current low marsh and certain transition zones would be eliminated. 



75 



