That's because the big sugar cane fields are south of the lake. Water in that region drains from north to south. Fields adjacent to the lake can't drain into the lake due to the dike.
correct but when it rains in those areas any flow from the lake to the south is stopped so those fields/homes won’t flood because those drainage canals will overtop
such was the case this week...when the Miami canal was opened with 1000 cfs flowing south until it rained 2 inches one day and 1 inch the next in those areas