 Establishment of the C & SF made Everglades National Park completely dependent upon another political entity for its survival . One of the C & SF 's projects was Levee 29 , laid along the Tamiami Trail on the northern border of the park . Levee 29 featured four flood control gates that controlled all the water entering Everglades National Park ; before construction , water flowed in through open drain pipes . The period from 1962 to 1965 was one of drought for the Everglades , and Levee 29 remained closed to allow the Biscayne <unk> — the fresh water source for South Florida — to stay filled . Animals began to cross Tamiami Trail for the water held in WCA 3 , and many were killed by cars . <unk> estimate the population of alligators in Everglades National Park was <unk> ; otters nearly became extinct . The populations of wading birds had been reduced by 90 percent from the 1940s . When park management and the U.S. Department of the Interior asked the C & SF for assistance , the C & SF offered to build a levee along the southern border of Everglades National Park to retain waters that historically flowed through the <unk> and into Florida Bay . Though the C & SF refused to send the park more water , they constructed Canal 67 , bordering the east side of the park and carrying excess water from Lake Okeechobee to the Atlantic . 
