The following sections include brief discussions of discharge characteristics of individual stations comparing the tidal ranges and response of each station to significant hydrologic events. To allow easy comparison of tidal ranges, water levels were converted to mean-normalized water levels (normalized water level). The mean water level during the 1999-2001 period was subtracted from the water level to compute a normalized water level. Because of their remoteness, the stations were not surveyed to a vertical datum. The mean water level of the rivers is typically lower during the winter and early spring along the southwest coast of Florida, and it is not unusual for strong southeast winds to precede a cold front and force water out of the estuaries. Then, strong northwest winds (20 to 25 miles per hour) occur after the front that forces water back into the estuaries.

Lostmans Creek Station

The Lostmans Creek normalized water level ranged from -1.64 to 2.13 ft during the study. Index velocities greater than 1 ft/s occurred during less than 10 percent of the study period. Computed instantaneous discharges at the Lostmans Creek station ranged from -2,600 ft³/s during the passage of Tropical Storm Harvey on September 21, 1999, to +2,400 ft³/s during the passage of Hurricane Irene on October 15, 1999. The maximum residual discharge of +1,560 ft³/s also occurred during the passage of Hurricane Irene, and the minimum residual discharge of -835 ft³/s occurred on March 27, 2000, during the passage of a strong cold front during a period of lower mean water level at the station.

Residual discharge for January through December 2000 was less than during 1999 because of less rainfall. Approximately 70 in. of rainfall fell on ENP in 1999 (average of 16 stations shown in fig. 1), whereas only 51 in. fell in 2000 (Everglades National Park, 1996-2001). The daily mean residual discharge during the study period ranged from -610 to +1,470 ft³/s. A strong cold front in March 2000 caused water to pile up in the mangrove forests and resulted in the largest negative daily mean residual discharge for the study period of -610 ft³/s. The rest of the year was relatively uneventful, with a maximum daily mean residual discharge of approximately 800 ft³/s, which was about half the maximum for 1999. Lostmans Creek absolute residual discharge (absolute value of residual discharge) was greater than 500 ft³/s for 20 percent of the study period, and absolute instantaneous discharge (absolute value of instantaneous discharge) was greater than 500 ft³/s approximately 50 percent of the study period.

Broad River Station

The Broad River station normalized water levels ranged from -2.03 to +2.05 ft during the study, with a typical springtide water-level range of approximately 2 ft. The maximum index velocity recorded was +2.99 ft/s during the passage of Hurricane Irene in October 1999, and the minimum index velocity, -1.78 ft/s, occurred during the passage of a strong cold front in January 2001. Computed instantaneous discharges at the Broad River station ranged from -2,400 ft³/s during the passage of a frontal storm system on April 30, 1999, to +3,500 ft³/s during the passage of Hurricane Irene on October 15, 1999. There were some periods when the instantaneous discharge did not reverse (move upstream) for as long as a month. The maximum residual discharge was +2,500 ft³/s during the passage of Hurricane Irene, whereas the minimum residual discharge was -1,700 ft³/s during the passage of a cold front on February 4, 1998. The Broad River station daily mean residual discharge ranged from -1,320 to +2,040 ft³/s.

Harney River Station

The Harney River station normalized water levels ranged from -2.95 to +3.42 ft, with a typical spring-tide water-level range of approximately 4 ft. Maximum velocities for flood tide occurred right of river center (looking downstream), and maximum ebb flows occurred left of river center based on acoustic discharge measurements. The maximum index velocity recorded was 2.7 ft/s during the passage of Tropical Storm Harvey on September 21, 1999, and the minimum index water velocity recorded was -3.2 ft/s earlier on the same day as winds blew onshore. Computed instantaneous discharges at the Harney River station ranged from -12,000 to +10,000 ft³/s during the study. The daily mean residual discharge during the study period ranged from -2,290 to +4,860 ft³/s.

Harney and Shark Rivers are both connected to Tarpon Bay. Acoustic discharge measurements on the Harney River approximately 300 ft downstream of Tarpon Bay from the June 1996 reconnaissance identified a short period of time when the Harney River flow was flooding (moving upstream), while the Shark River flow slightly downstream of Tarpon Bay had been ebbing a short time before. These measurements suggest that during specific periods, water can move upstream into Tarpon Bay from the Harney River while Tarpon Bay water is flowing downstream into the Shark River. The contrary flood and ebb flows are believed to be a rapid occurrence (duration less than 15 minutes), because flow in the Shark River was upstream (flooding) when it was measured about 10 minutes later. These contrary flows would tend to reduce the daily mean residual discharge values for the Harney River station while artificially increasing those at the Shark River station. However, the short duration of the flows and the uncertainty of how often the contrary flows occur suggest they will probably not significantly affect long-term mean residual discharges for either station.

Shark River Station

The Shark River station normalized water levels ranged from -2.63 to +3.08 ft. The maximum water level occurred during the passage of Tropical Storm Harvey on September 21, 1999, and the minimum water level occurred as Hurricane Georges passed offshore in the Gulf of Mexico on September 25, 1998. Similar to the Harney River station, maximum velocities for flood flows occurred right of the river center and maximum velocities for ebb flow occurred left of river center based on acoustic discharge measurements. Index velocities ranged from -2.5 to +3.0 ft/s, and a typical tidal cycle range was usually ±2 ft/s. The maximum water velocity occurred during the passage of Tropical Storm Harvey on September 21, 1999, and the minimum occurred during the passage of Tropical Storm Mitch on November 5, 1998. The passage of Tropical Storm Mitch on November 5, 1998. The Shark River station instantaneous discharges were slightly less than the Harney River station and ranged from -10,000 to +8,000 ft³/s. The daily mean residual discharge during the study period ranged from -1,970 to +3,790 ft³/s.

North River Station

The North River station normalized water levels ranged from -1.67 to +2.06 ft. The maximum water level occurred during the passage of Tropical Storm Harvey on September 21, 1999, whereas the minimum water level occurred during the passage of a cold front on January 15, 2000. Index velocities ranged from -1.1 to +1.8 ft/s and a typical tidal cycle range was -0.2 to +0.4 ft/s. The maximum water velocity occurred during the passage of Hurricane Irene on October 15, 1999, and the minimum velocity occurred during the passage of Tropical Storm Harvey on September 21, 1999. The North River station instantaneous discharges were the lowest of the five stations and ranged from -1,100 to +1,100 ft³/s. The daily mean residual discharge during the study period ranged from -360 to +530 ft³/s.