Our Focus Today
Other issues
While the primary issue being addressed by W.A.R. is restoring peak scouring flows, other problems have been identified. Some of these problem areas will likely see improvement when flow is restored. Others fall outside of W.A.R.'s ability to address them.
Biological Impairment
Prior to construction of the Inglis Dam and eventual aging of Lake Rousseau, the predominant flow feeding the Lower Withlacoochee River would have been spring flows from the Rainbow River and other springs upstream and downstream of the Rainbow River. A predominance of spring water with high clarity likely allowed adequate sunlight to sustain a healthy community of submerged aquatic vegetation in the lower river. The photosynthesis of this vegetative community would have served as the base of an organic-compound-based food web similar to the Rainbow River, sustaining high concentrations of fish and other wildlife. Over the past 50+ years those spring-fed base flows have declined significantly, and nitrogen levels have increased. As evidenced by W.A.R.’s multi-year study, the quality and quantity of the water feeding the Lower Withlacoochee River has likely changed markedly due to impactful human developments in the contributing surface and groundwater basins, the impoundment of Lake Rousseau, the increase both nitrogen and phosphorous in the lake, the excessive growth of plants in the lake, and attempts to control of those plants with herbicides.
Pollution Tolerant Fish Dominance
Based on FWC electrofishing data, both fresh and saltwater fish populations exist in the Lower Withlacoochee River. In terms of fish species, threadfin shad were most abundant, and account for about 29% of the freshwater fish population biomass. This species of fish is a plankton feeder, presumably feeding on the abundant particulate matter (live and dead phytoplankton, pseudo- plankton, and zooplankton) entering the lower river through the Inglis Bypass Channel from Lake Rousseau. The largest fraction of freshwater fish in the lower river as indicated by biomass were non-game species, including gar and bowfin. These species are adapted to survive and dominate in low oxygen waters with decaying organic matter. The most abundant saltwater fish species was striped mullet. These catadromous fish feed on benthic and attached algae in coastal, spring-fed rivers. Smaller populations of spotted sunfish, largemouth bass, and snook indicate that this impaired lower river segment still retains some habitat value for prized game fish.
Poor Habitat for Macroinvertebrates
FDEP’s habitat assessment data for the Lower Withlacoochee River indicated poor environmental conditions for supporting healthy macroinvertebrate populations. These tiny organisms include aquatic worms, insects, and other invertebrates that normally provide the first level of a healthy aquatic food web that supports fish and other vertebrate wildlife. Adequate populations of these organisms are dependent upon suitable habitat, including good water quality, adequate freshwater flows, and the presence of native submerged aquatic vegetation. The macroinvertebrate data collected in the study area indicate a lack of suitable habitat and confirm the predominance of pollution-tolerant organisms in the lower river, especially just below the discharge from Lake Rousseau through the Inglis Bypass Channel gate. Many of the organisms that were found in this area subsist on decaying organic matter and are tolerant of polluted water conditions.