Habitat Assessment and Restoration on the Peace River, Withlacoochee River, and Myakka River
Researchers surveying a cross section of the Peace River.
Habitat degradation is the primary factor causing the decline of biodiversity in aquatic ecosystems of the southeastern United States. Sedimentation is the leading issue causing degradation, loss of habitat complexity, and impairment of river habitat and biological communities. The initial step in restoring natural function and biodiversity of rivers affected by habitat degradation is identifying those areas contributing to impairment throughout the system. Once impaired areas are identified, management can correct the problem through prevention, mitigation, stabilization, or restoration. This need to identify areas of riverine habitat degradation led the FWRI to conduct threats assessment projects on the Peace River and Withlacoochee River watersheds.
The Peace River and Withlacoochee River are large blackwater rivers in peninsular Florida. Both watersheds have experienced high levels of habitat degradation due to urbanization, agriculture, industry, mining, and altered flow regimes. The objectives of this project were to identify and inventory the location and magnitude of habitat degradation within the Peace River and Withlacoochee River watersheds using methods developed by the United States Fish and Wildlife Service (USFWS). Based on the results, researchers developed a prioritized basin restoration plan for each watershed, which can guide entities to implement conservation and restoration efforts. Additionally, biologists conducted a fish assemblage assessment of the Withlacoochee River, since data were lacking on the system.
During the threats assessment study (2015-2019), biologists assessed approximately 168 river miles in the Peace River Watershed and evaluated 512 impairment sites and 62 unpaved road crossing sites. Results revealed that certain reaches of stream and riparian habitats have been severely degraded, primarily due to ranching, agriculture, and denuded riparian forests. In the Withlacoochee River Watershed, biologists identified 24 impairment sites and 20 unpaved road crossing sites along 132 river miles. Overall, the assessed areas within the Withlacoochee River Watershed were stable and riparian buffers were in excellent condition. While we located few impairment sites within the Withlacoochee River Watershed, the dam structures at Lake Rousseau were considered the largest threat to the river system due to potential impacts on water quality, aquatic species, sediment transport, and instream habitat.
Based on findings of the threats assessment survey, researchers from FWRI secured funding to restore and monitor two severely degraded streambank locations along the Peace River, as well as conduct a threats assessment and fish assemblage assessment of the Myakka River Watershed. FWRI researchers partnered with the USFWS to restore the streambanks and riparian habitat, utilizing Natural Channel Design. Natural Channel Design applies fluvial geomorphology to create resilient streams that maximize function by emulating natural conditions. The first 450-ft streambank on the Peace River was restored in June 2020 and the second 1,000-ft streambank was restored in February 2021. Permanent cross-sections and photo-points taken pre-and-post restoration confirmed that restoration successfully stabilized both streambanks.
During 2019 to 2022, approximately 45.2 mi of the Myakka River and its tributaries were surveyed as part of the Myakka River threats assessment. Within the watershed, 67 impairment sites and 35 unpaved road-stream crossings were identified and assessed. Restoration recommendations for impairment sites and unpaved road-stream crossings were developed based on findings from the survey. Annual fish assemblages were monitored by electrofishing during 2020-2022, including catch and release of 12,816 fish representing 25 families and 46 species.
Left: severely degraded bank along the Peace River. Right: restored streambank along the Peace River.