dissolved oxygen in bottom waters, 

 particularly in the dead-end canals. 

 Average dissolved oxygen values in 

 August were below the state water 

 quality standard of 4 mg/1 in the 

 canals and only slightly above the 

 state standard in the bay. 



Yokel (1979) found that ben- 

 thic life was severly limited by 

 the low dissolved oxygen levels, 

 prevalent throughout summer and fall. 

 Although pelagic fishes apparently 

 were not adversely affected by the 

 stratification, they were excluded 

 from large areas of the Gordon Riv- 

 er by extremely low salinities dur- 

 ing several months. Planktonic or- 

 ganisms in the lower bay were washed 

 out of the estuary by the high dis- 

 charges, which may have negatively 

 affected planktivorous fishes (Yo- 

 kel 1979). 



Reduced mixing caused by the 

 high volume of freshwater discharge 

 inhibited aquatic life in the es- 

 tuarine system and lowered water 

 quality to levels potentially haz- 

 ardous to public health in the 

 dead-end canals, which tended to trap 

 and concentrate organic materials, 

 including pathogenic bacteria (Hicks 

 1979b) . A residential development 

 is associated with the dead-end ca- 

 nals. 



low, density currents can be a great- 

 er mixing force than tides. 



The Big Cypress Basin Board, 

 which now has management jurisdic- 

 tion over the watershed affecting 

 the Gordon River-Naples Bay estuary, 

 is planning to redesign the water 

 management system to reduce wet sea- 

 son discharge to the estuary and, at 

 the same time, alleviate other prob- 

 lems that have been caused by dis- 

 ruption of natural drainage patterns. 

 In effect, what the board intends 

 to do is utilize the many drained 

 or partially-drained wetlands in 

 the watershed for water storage and 

 recharge areas (Simpson 1979). Hold- 

 ing the water on the land will have 

 two beneficial effects on water de- 

 livery to the bay. (1) Because of 

 increased evapotranspiration there 

 will be a decrease in the total quan- 

 tity of water going to the bay. (2) 

 Because of increased infiltration 

 into the substrate there will be an 

 increase in the ratio of delayed run- 

 off to immediate runoff, which will 

 reduce peak flows and increase base 

 flows, making the seasonal variation 

 in water flow to the bay less pro- 

 nounced. The board will try to cre- 

 ate density currents in the bay to 

 optimize mixing of bay and canal wa- 

 ters throughout the year. 



According to van de Kreeke 

 (1979), water circulation in the 

 dead-end canals would be substan- 

 tially increased if freshwater dis- 

 charge were reduced to an order of 

 magnitude of 1 m /s. His calcula- 

 tions indicate that this rate would 

 drive the circulation of water in the 

 bay and canals. In Gulf of Mexico 

 estuaries, where tidal amplitudes are 



The new design will also raise 

 the dry-season water table, reduce 

 forest fires, prevent saltwater in- 

 trusion, increase the availability 

 of irrigation water for agricultural 

 crops, and increase the productivity 

 of wetlands and their ability to sup- 

 port wildlife. By utilizing wetland 

 systems for water storage and re- 

 charge, the board will restore their 

 natural function. 



409 



