CHAPTER 5 

 SURFACE HYDROLOGY AND WATER QUALITY 



5.1 HISTORICAL PERSPECTIVE 



The quantity, distribution, and 

 quality of freshwater within the 

 Everglades, more than any other en- 

 vironmental characteristic, influ- 

 ences the capacity of this area to 

 support its unique fish and wildlife 

 resources. Before man's influence, 

 the terminal Everglades received a 

 seasonal pulse of surface sheetflow. 

 It began in June or July, spread 

 slowly toward the coast, and reached 

 peak flow and stage around October. 

 As Lake Okeechobee filled with fresh 

 water from direct rainfall and 

 Kissimmee River runoff, it eventual- 

 ly spilled over at points in its 

 southern boundary and began filling 

 the 64.4 km (40 mi) wide river of 

 grass. As the lake continued to 

 rise due to heavy summer rainfall, 

 the entire southern lip of the lake 

 would gradually become obscured by a 

 continuous connection between the 

 open water to the north and the saw- 

 grass plains to the south. 



Water levels in the pre-drain- 

 age Everglades were on the average 

 much higher than today, occasionally 

 leading early investigators to refer 

 to it as a "lake" (Parker 1974). 

 The Atlantic Coastal Ridge acted as 

 a partial dam on the Everglades 

 eastern boundary. Water periodical- 

 ly spilled over this dam through the 

 lower transverse glades, through 

 falls eroded in the porous lime- 

 stone, or over the top of the ridge 

 when waters were especially high. 

 The relative hydraulic head (ap- 

 proximately 3 m or 10 ft during low 

 water) resulted in numerous artesian 

 springs in downstream Biscayne Bay; 

 apparently outflow occurred through 

 subterranean solution channels. 

 Toward the southwest the predrainage 



river of grass flowed slowly in a 

 southwesterly trending arc through 

 luxuriant sawgrass marshes, open 

 water sloughs, and mangrove covered 

 shorelines. 



Beginning in the early 1900's 

 this pattern of water abundance 

 began to change significantly. 

 In 1882 the construction of the 

 Caloosahatchee Canal signified the 

 beginnings of a physical alteration 

 process in the hydrologic regime 

 that continues today. The period 

 1905 to 1913 saw the North New River 

 and Miami Canals completed and 

 placed into operation. By 1921 the 

 Hillsboro and West Palm Beach Canals 

 were added. At the same time (1916- 

 1924), the St. Lucie Canal was dug 

 in order to provide drainage for 

 Lake Okeechobee. However, a hurri- 

 cane in 1926 set back the usefulness 

 of the St. Lucie Canal for this 

 purpose by overloading it with sedi- 

 ment. In 1935 redigging of the 

 canal restored it to its original 

 design conditions. Several other 

 major canals in the Miami area, 

 mainly the Tamiami, were also con- 

 structed during the 1920's. 



Also in the 1920's, construc- 

 tion of a levee, the Hoover Dike, 

 around the south and east of Lake 

 Okeechobee was begun. Continual 

 expansion of this structure for 

 flood purposes has resulted in a 

 levee some 136.8 km (85 mi) long 

 around the entire southeast portion 

 of the lake, beginning north of the 

 Caloosahatchee Canal. Most of these 

 major structures were in place by 

 the mid to late 1930's. 



Beginning in the late 30's it 

 became apparent that the uncontrol- 

 led drainage of the Everglades 



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