< 

 >- 



£ 



Q. 



X 

 (0 



< 



LAND LOSS BY 

 HYDROLOGICAL UNIT 

 1955-1978 



Y : 0.855 |X| - 0.0492 



% CANAL DENSrTY 

 IN 1955 



Figure 2. The percent annual wetland loss as related to the average canal 

 density for the six hydrological units of the deltaic plain (from Wicker 1980) 



1.0 



oc 



< 



UJ 



>- 



s 



a 

 o 



_l 



o 



z 



0.5 



intercept -* 



of 



linear 



regression 



Ys 



R2 



0.346 

 = 0.88 



IXI - 0.0713 



.1955-1978 



1935-1958 

 1891-1935 



*" historical 

 gain 



1 



% CANAL DENSITY 



Figure 3. Land loss for three intervals between 1891 to 1978 in relation to 

 the average canal density for those intervals. The intercept of a simple 

 linear regression based on these three points is compared with the historical 

 net gain for the last 7000 years (Gagliano 1973; Wicker 1980; Gagliano et al . 

 1981). 



76 



