Technical reports

This report documents long-term monitoring activities at the spring and spring run.

In 1989 the District’s Governing Board created a Technical Advisory Committee to draft an Environmental Water Management Plan (EWMP) that would allow the District to make non-flood protection discharges to achieve the environmental and other core mission goals of the Upper St. Johns River Basin project. This report is an update to that original document and will serve as an appendix to the U.S. Army Corps of Engineers’ Final Water Control Manual.

The St. Johns River Water Management District owns 8,355 acres in Marion and Lake counties known as the Sunnyhill Restoration Area. The District is evaluating sites having the potential for groundwater recharge using surface water that may not otherwise recharge due to flow paths or geologic conditions. This report documents evaluation of two sinkholes at the Sunnyhill property.

This report documents the minimum levels determination for Lake Butler in Volusia County, Florida.

Fourteen springs and their associated spring-run streams in north and central Florida were intensively sampled in 2015. This study quantitatively sampled physical-chemical (physicochemical) characteristics and biological measures in these spring-run streams.

This report summarizes trends in external total phosphorus and total nitrogen loading and water quality through 2019–20 for eight major and three minor lakes in the Upper Ocklawaha River basin.

The St. Johns River Water Management District has monitored phytoplankton in the Lower St. Johns River Basin (LSJRB) since the early 1990s. The LSJRB experiences severe cyanobacterial blooms in its freshwater and oligohaline reaches. Analyses were conducted of relationships between cyanobacteria and hydrologic and water quality factors for six sites in the LSJRB. This report documents the analyses and discusses alternative or complementary methods that may improve monitoring of cyanobacterial blooms.

Biosolids, the solid residuals from the treatment of domestic wastewater, are beneficially used to supplement or replace fertilizer in agricultural production throughout the world. The report documents the current study, which examines the relationship between the timing and magnitude of Class B biosolids applications and trends in total P and total nitrogen fluxes in seven Upper St. Johns River Basin tributaries and one Lower St. Johns River Basin tributary within the St. Johns River Water Management District.

This report documents the minimum levels determination for lakes Brooklyn and Geneva in Clay and Bradford counties, Florida.

Fourteen springs and their associated spring-run streams in north and central Florida were intensively sampled in 2015 for selected physicochemical characteristics and quantitative measurement of submerged aquatic vegetation (SAV — macrophytes and algae) and associated macroinvertebrates. This report focused on the algal community data.

The St. Johns River Water Management District implemented a project to drill a corehole as part of an ongoing investigation of the Floridan aquifer system with a special focus on characterizing the confining units and aquifer of the Floridan aquifer system. Data collected during the investigation assists in regional hydrogeologic mapping.