Technical reports

The St. Johns River Water Management District (SJRWMD) has identified brackish groundwater, brackish surface water, and seawater as potentially significant alternative sources of supply to meet projected 2020 demands. The use of these mineralized water sources requires management of the concentrate that is a byproduct of the demineralization. The relative suitability of various demineralization concentrate management alternatives was evaluated for the SJRWMD area.

This study examines the hypothesis that alligator mortality in Lake Griffin is due to a syndrome of thiamin deficiency induced by eating a diet of fish that may be high in thiaminase.

This report summarizes published and unpublished literature concerning the effects of water flow and level changes on fish populations, with an emphasis on freshwater fishes in Florida and the adjacent southeastern United States.

This document is an annotated bibliography of the effects of water levels on fish populations, with special reference to Florida fishes, habitats, and systems. The coverage is primarily 1980–2000.

This publication reports the results of surveys of snail kite nesting activity conducted during the spring of 2000 and 2001 in the Blue Cypress marshes within the watershed of the upper St. Johns River.

This study determined the relationship of submerged aquatic vegetation in the Indian River Lagoon to water quality, submarine photosynthetically active radiation, and underwater light attenuation. Monitoring included both healthy and stressed seagrass beds.

This publication reports the results of a 30-month-long study undertaken to determine the potential magnitude of nutrients flowing into (or “loading”) the Indian River Lagoon system.

This publication reports on investigations into the continuing, unexplained mortality of alligators in Lake Griffin in central Florida.

This study was conducted to evaluate the eutrophic condition of the zooplankton in Lake Jesup, using Lake Washington as a comparison.

This project was undertaken to evaluate the effects of possible future fluctuations in Blue Cypress Lake water levels. A one-year study was conducted of the structure of aquatic invertebrate communities inhabiting Blue Cypress Lake in order to evaluate the ecological condition and trophic status of this component of the St. Johns River ecosystem.

This report examines two alternatives for reducing the flood elevations in Kanapaha Prairie by storing storm water in the Levy Lake area.

This document was prepared as a guide to understanding how to maneuver through the St. Johns River Water Management District’s database website. It describes the options available and the basic functionality of the various pages in this site.

This report documents an investigation of sediments from 40 sites in the St. Johns River Water Management District performed to increase the overall coverage of a previous study and to improve the understanding of sediment quality in 10 areas identified as having elevated levels of contaminants.

This report documents a study to develop a data analysis approach or method that can be used to determine background metal concentrations and show how that information can be applied to a wide region.

The purpose of the report was to document development of a planning-level cost estimate for mitigating potential impacts to wetland and aquatic communities using an impact assessment and cost estimating methodology developed in a previous study.

The report addresses the availability of lower-quality or brackish groundwater as an alternative water supply source within priority water resource caution areas of the St. Johns River Water Management District.

This report, the third in a series concerned with the feasibility of developing brackish groundwater sources to help meet municipal water supply needs within the St. Johns River Water Management District, presents a cost analysis.

A study was conducted as part of a long-term effort to monitor wading bird populations in the Upper St. Johns River Basin as to how populations relate to the restoration of marshes in the headwaters of the St. Johns River. This report summarizes data collected between 1998 and 2000 and expands on data collected between 1993 and 1995 for a report published in 1996.

This report documents a study to determine historical changes in sediment and nutrient accumulation rates over the past 100 to 150 years in the Harris Chain-of-Lakes. As a part of the study, past trends in water quality and plant communities in the study lakes were reconstructed.

This report documents a review of evapotranspiration literature, compares water requirements for consumptive use permitting, and reviews the agricultural field scale irrigation requirements simulation (AFSIRS) model.

To determine the degree to which biological communities in the St. Johns River Water Management District’s water bodies have been impaired, a study was conducted on benthic macroinvertebrate communities in the Lower St. Johns River Basin and its tributaries. This report classifies and ranks the macroinvertebrates and their communities by degree of water body impairment.

This study was conducted as part of the St. Johns River Water Management District’s (SJRWMD) minimum flows and levels program within the SJRWMD Division of Water Supply Management to determine the potential harm to species that live in wetlands if the hydrology of the wetlands were to be altered. The report lists the natural wetlands community types by county.

A time domain electromagnetic survey was performed at four sites in the St. Johns River Water Management District to determine the vertical distribution of formation electrical resistivity.

This report outlines a five-year study during which two varieties of citrus were subjected to increasing amounts of salt in irrigation water in order to determine levels at which the ability of the trees to produce fruit were adversely affected by the salt.

This report documents the steps to take in identifying the Chironomidae in the Southeastern Coastal Plain.

This district water supply plan addresses current and future water demands, traditional and alternative water sources, and water supply infrastructure improvements required to meet 2020 water supply needs while sustaining water quality, wetland and aquatic systems, and existing legal uses.

This report documents the trapping and counting of mice in the area of Lake Apopka, Fla., in an attempt to determine an explanation for the rapid multiplication of the animals in the area.

This management plan has three objectives: to establish goals and priorities for the treatment of exotic plant species on St. Johns River Water Management District lands, to describe methods that will be used to treat various exotic plants, and to outline departmental responsibilities and procedures for implementing plant control activities.

This study was conducted to determine the changes in fish and aquatic invertebrate populations based on possible reduction in the flows of water in the Wekiva and Little Wekiva rivers.

This report documents the applicability of this technology for renovation of urban lakes, based on results of a periphyton filter at Lake Wade in Orlando, Fla., constructed, operated, and monitored by the St. Johns River Water Management District and its contractors.

This report documents findings from the study of benthic invertebrates at four lakes to determine if alum is a viable treatment to remove pollutants from water.

A survey of the benthic macroinvertebrate communities of the region’s lakes, streams, and estuaries was performed to determine the degree to which biological communities in the water bodies of the St. Johns River Water Management District has been impaired by organic and toxic metal contamination of sediments.

Interactions between groundwater and surface water levels is discussed and evaluated using various models.

This report outlines the development and demonstration of linear programming optimization models and mixed integer decision models for use in water resource management.

This report is a peer review of the processes applied to establish minimum flows and levels (MFLs) for streams and rivers in the Wekiva River Basin. This review evaluates the goals, methodologies, and assumptions applied by the St. Johns River Water Management District to develop the MFLs for the basin.

The Blue Cypress Marsh Water Conservation Area and the Blue Cypress Water Management Area were surveyed from 1996 to 1998 for foraging and nesting snail kites as a comparison with previous observations.

A population-based water use model was developed for the St. Johns River Water Management District to help plan for future water demand.

The purpose of this study was to determine the cost effectiveness of specific water conservation practices by comparing the amounts of water saved with the cost of implementing the water conservation practice.

An audio magnetotelluric (AMT) survey was performed at 14 sites in the Titusville area over a three-day period in 1998 to provide a gross approximation of an electrical log as performed in a borehole without the significant expense of drilling, completing, and logging such a borehole.

A study of sediment and nutrient deposition in Lake Dora and Lake Eustis was undertaken with the primary goal of quantitatively estimating changes in net concentrations.

This report describes the data reconnaissance, model development, model calibration, and results of the hydrologic and hydraulic simulations of the Nassau River Basin using models maintained and distributed by the U.S. Army Corps of Engineers Hydraulic Engineering Center.

This report presents data collected from the Orlando Utilities Commission Southeast test well, located near Lake Nona in south-central Orange County, Fla.

This document was prepared to comply with the requirements of Section 373.207, Florida Statutes. This is the fourteenth annual report on the inventory of abandoned artesian wells in the St. Johns River Water Management District and on the work plan for controlling or plugging inventoried wells.

The report documents investigation by the St. Johns River Water Management District of alternative water supply strategies within priority water resource caution areas. One strategy investigated the use of reclaimed water for irrigation in areas with high agricultural water withdrawals from the Floridan aquifer — the citrus-growing regions in Orange, Lake, and Seminole counties and the fern-growing areas of northwest Volusia and southeast Putnam counties.

This report documents work to estimate the cost of replacing potable quality water used for landscape irrigation with alternative supplies. Specifically, the purpose of the report was to determine the quantity of publicly supplied potable water that could effectively be replaced with water from shallow, self-supply irrigation wells or with reclaimed water and to estimate the costs associated with each of these alternative supplies.

The St. Johns River Water Management District identified several ways to maintain lake levels and/or reduce the duration of low water-level periods in Orange Lake during droughts. This report documents the possible geologic and groundwater effects of sinkhole discharge control in the Heagy-Burry Park area. A groundwater model was developed to evaluate local groundwater levels and drawdowns in the area that is affected by a sinkhole discharge.

This report describes the results of a study of the early successional characteristics of plant and wildlife communities developing on the Lake Apopka Marsh Flow-Way Demonstration Project. The study was conducted to gain an understanding of possible biological community development patterns that might be expected on former agricultural lands undergoing restoration to wetland by the St. Johns River Water Management District.

A baseline monitoring project was performed to assess the status of the freshwater sediment quality at 86 selected stations in the region of the St. Johns River Water Management District. This report documents sediments in water bodies as an indication of aquatic ecosystem health.

This report documents a study to determine the survival of the Florida apple snail as a critical food web component in Florida wetlands in consideration of restoration efforts ongoing in central and south Florida.

This report is an environmental risk assessment of the Duda Farms property purchased by the St. Johns River Water Management District for restoration. It documents potential ecological risks and describes how potential risks can be addressed through site management strategies.

This study was conducted to determine the long-term effectiveness of wetland soils to retain nutrients and to determine the biological processes that occur in soils after former farmlands are flooded after being restored to wetlands.

Econlockhatchee River survey data were reviewed to determine differences in elevation reports. Hydrologic factors were also studied to explain water body elevations.

This report describes the data reconnaissance, model development, model calibration, and results of the hydrologic, hydraulic and water quality simulation of the Black Creek Basin using the U.S. Environmental Protection Agency’s storm water management model.

The St. Johns River Water Management District evaluated the feasibility of increasing the flow of surface water to the Floridan aquifer through drainage wells in Orange and Seminole counties.

The purpose of this study was to develop a stormwater management master plan for Lakes McCoy and Coroni, and for the Prevatt watershed and the associated primary drainage systems. The study included an assessment of water quantity and quality.

A study of historic, whole-basin sediment and nutrient deposition was conducted in Lake Griffin in two phases. Phase I, a feasibility study, demonstrated that historic sediment and nutrient deposition could be estimated using historic and survey sediment cores. Phase II refined estimates by collecting additional historic cores and by collecting and sectioning longer survey cores at finer intervals.

This paper provides a literature review of the biological effects of aluminum, primarily with respect to the mechanisms of aluminum bioavailability and toxicity and how its biological effects are best predicted.

As part of the St. Johns River Water Management District’s investigation of alternative water supply strategies, this report evaluates the impact of implementing water conservation rate structures as a means for water utilities to moderate consumption through a pricing mechanism that increases the price of water as usage increases.

This document was prepared to comply with the requirements of Section 373.207, Florida Statutes. This is the thirteenth annual report on the inventory of abandoned artesian wells in the St. Johns River Water Management District and on the work plan for controlling or plugging inventoried wells.

The objective of this project was to continue measurements of ecosystem succession in the Lake Apopka Marsh Flow-Way Demonstration Project and to initiate measurements in the full marsh. Earlier ecosystem succession studies (November 1990–February 1993) revealed a pattern of increasing coverage by a few highly competitive plant species. To provide a more complete assessment of ecosystem development on the site, a second phase of the study was implemented from August 1993 to March 1995.

This report documents the sedimentation rates of Lake Jesup and possible reasons for the sediment’s uneven distribution.

This study included an examination of the geology and hydrogeology of the groundwater system of central Indian River County to determine a potential supplemental water resource for citrus irrigation and frost-and-freeze protection.

The objectives of the study were to quantify the potential phosphorus mobility and sink size of recently flooded soils, to determine the time period before the existing soil horizons can function as net phosphorus sinks, and to determine the long-term phosphorus storage, based on retention capacity of soils.