Technical reports

A time domain electromagnetic survey was performed at seven sites in the St. Johns River Water Management District during June 1996 as a way to measure the vertical distribution of electrical resistivity. The report documents soundings to determine thickness of groundwater sources.

This report documents a project to determine numbers of wading birds using the Upper Basin of the St. Johns River, both as foraging habitat and for nesting, and to use these data in assessing the success of the upper basin project in restoring productive wildlife habitat.

To address the future needs for water resource caution areas, including all or portions of Volusia, Brevard, Orange, Seminole, Osceola, Lake, St. Johns, and Flagler counties, the St. Johns River Water Management District initiated an alternative water supply strategies investigation. Cost information for public water supply and wastewater system components is presented in this document as a tool for estimating costs during the conceptual planning stage of potential facility projects relating to alternative water supply strategies.

The St. Johns River Water Management District initiated an investigation of the feasibility of alternative water supply strategies because increasing groundwater usage is not likely to occur without causing unacceptable environmental impacts. This document addresses the possible use of aquifer storage recovery.

Groundwater flow and chloride concentrations were modeled by the St. Johns River Water Management District on a regional basis in northeast Florida, but subregional-scale models were required in specific areas to address conditions at individual wellfields.

This report includes an initial plant species list for 41 natural community types occurring in the St. Johns River Water Management District (SJRWMD), an initial checklist of plant species, and a list of plant specimens as an initial biological inventory of SJRWMD.

This is the third in a series concerned with the feasibility of developing selected surface water sources to help meet municipal water supply needs within the St. Johns River Water Management District. This report presents the results of the quantitative water supply availability and yield analysis.

This report documents the development of the biohydrologic criteria and methods used to evaluate the ecological effects of different surface water management alternatives on the Orange Creek Basin.

This report investigates the costs and benefits associated with the conversion from semi-enclosed seep irrigation to either automated seep or automated sub-drip irrigation for potato production in northeast Florida. These costs and benefits are estimated at the level of the individual grower and for the public at large.

Gizzard shad, Dorosoma cepedianum, have achieved a large biomass in Lake Apopka, Florida. Removal of a large portion of this biomass will remove significant amounts of phosphorus in this highly eutrophic lake and help create conditions more conducive for establishing desirable sportfish populations. This report provides population estimates of gizzard shad prior to a 1995 harvest and evaluates methods used to produce population estimates.

Gizzard shad, Dorosoma cepedianum, have achieved a large biomass in Lake Apopka, Florida. Removal of a large portion of this biomass will remove significant amounts of phosphorus in this highly eutrophic lake and help create conditions more conducive for establishing desirable sportfish populations. Gizzard shad were harvested from Lake Apopka between March and May 1996. Evaluation of this restoration method requires determining the proportion of the total gizzard shad population harvested. This report provides population estimates of gizzard shad prior to the harvest and evaluates methods used to produce the population estimates.

This report documents findings of water conservation and reuse of reclaimed water within water resource caution areas identified in Water Supply Needs and Sources Assessment (Vergara 1994), specifically with assessing the effects of water use restrictions on actual water use within the Wekiva River Basin.

This report is a part of the overall scope of assessing the technical, environmental, and economic feasibility of mitigating or avoiding impacts to native wetland communities that could result from projected future (year 2010) groundwater withdrawals in water resource caution areas.

This report documents the use of drainage wells in Orange and Seminole counties since 1905, which are primarily to provide surface drainage and to prevent flooding in closed surface basins.

This report is the fourth in a series concerned with the feasibility of developing selected surface water sources to help meet municipal water supply needs within the St. Johns River Water Management District. This report presents the results of the cost estimation for water supply development at withdrawal sites in Lake Griffin (Haynes Creek), the St. Johns River near Cocoa, the St. Johns River near Titusville, the St. Johns River at Sanford (Lake Monroe), and the St. Johns River near DeLand.

This report, the second in the aquifer storage recovery (ASR) series, applies an ASR feasibility tool to selected sites within the St. Johns River Water Management District as part of continuing investigations of alterative water supplies.

This study assessed the feasibility of a regionally interconnected reuse system in Brevard and Indian River counties to transport reclaimed water to locations in Brevard and Indian River counties for use in irrigating citrus or for other reasonable-beneficial uses.

This document is a bibliographic listing of references and information about the Indian River Lagoon.

This is the second of three reports that address the feasibility of developing brackish groundwater resources to help meet future public supply needs. This report reviews relevant information and technical literature on technologies available to treat brackish groundwater and disposal options available to manage the waste concentrate stream associated with brackish water treatment.

Paleolimnological techniques were used to examine historical bulk sediment accumulation and nutrient sequestering in Lake Hell ’n’ Blazes, Sawgrass Lake, and Lake Washington, within the upper St. Johns River drainage basin. At selected sites in each water body, soft-sediment depth was measured to ascertain the distribution of organic deposits.

Sediment studies in Lake Apopka were undertaken to characterize and determine the origins of the flocculent and consolidate sediment layers in the lake, and to estimate lake basin sedimentation of mass, organic matter, total phosphorus, and inorganic phosphorus.

This report documents how rainfall data are essential for many hydrologic and engineering studies, including the St. Johns River Water Management District’s consumptive use and environmental resource permitting activities. Data are also used in hydrologic and engineering studies related to management plans for surface water basins. This report is an update of one of the reports from the former series about the summary of monthly and annual rainfall data through 1985 and includes the 1961–90 rainfall normals. It replaces the former report.

This report documents the St. Johns River Water Management District’s request to the Florida Fish and Wildlife Conservation Commission to allow the large-scale harvest of rough fish (gizzard shad, gar, and tilapia) from Lake Apopka to remove nitrogen and phosphorus from the lake as well as potentially change the lake food chain. It also lists the results of harvesting the rough fish.

The St. Johns River Water Management District (SJRWMD) has determined that increased groundwater withdrawals could adversely impact area water resources, especially wetland systems located near existing water supply wellfields. Because of these adverse impacts, SJRWMD investigated the technical, environmental, and economic feasibility of alternative water supply strategies, including the development of additional surface water supplies.

This study comprised a systematic weekly search of the Blue Cypress Marsh Water Conservation Area and the Blue Cypress Water Management Area, Indian River County, for nesting snail kites.

Groundwater comprised about 70% of the 1990 total water use in the St. Johns River Water Management District. This use is expected to increase substantially by 2010. The resulting increase in groundwater withdrawals can lead to a reduction in spring discharges, among other impacts. This publication presents methods to quantify the impacts of reduced spring discharges that would occur because of the projected groundwater withdrawals for 2010. These methods were applied to evaluate the impacts of 31 springs in the central Florida area.

This report is the second in a series of three that address the feasibility of developing surface water for domestic water supply within the St. Johns River Water Management District. The objective of surface water withdrawal site selection is to identify candidate surface water supply source locations that are within reasonable proximity to centers of significant increases in regional domestic water supply demand.

This report is in compliance with legislation that requires each water management district to completely evaluate their water needs and sources through the year 2010 and delineate critical areas identified as water resource problems. This report presents systematic modeling methods for determining optimum water supply strategies that satisfy various environmental and hydrological requirements.

The report outlines methodology for collection, development, presentation, and utilization of information concerning public water supply systems’ facilities and wastewater systems’ facilities in an effort to investigate potential alternative water supply strategies relative to systems interconnection.

The report documents the St. Johns River Water Management District’s evaluation of several potential consequences of possible water supply alternatives, such as changes to sensitive natural systems, particularly wetlands.

This report assesses water conservation and reuse of reclaimed water as effective alternative water supply strategies as well as addresses replacement of potable-quality water for landscape irrigation.

This report investigates the use of reclaimed water in high agricultural areas, identified by the St. Johns River Water Management District as citrus-growing regions along the Lake Wales Ridge in Orange, Lake, and Seminole counties and the fern-growing areas of northwest Volusia County and southeast Putnam County.

The purpose of this report was to determine the potential impacts of water conservation rate structures on reducing potable water consumption and thereby extending the viability of current water supply sources as part of the St. Johns River Water Management District’s ongoing efforts to manage water resources.

This task deals with assessing the effects of water use restrictions on actual water use within the Wekiva River Basin as part of the St. Johns River Water Management District’s investigation of alternative water supply strategies.

This report addresses the evaluation of the cost effectiveness of evaporative treatment processes, assessing water conservation and reuse of reclaimed water as effective alternative water supply strategies.

Accurate and reliable water quality data are required to characterize groundwater chemistry for use in groundwater resource management. This report summarizes the groundwater quality of the Floridan, intermediate, and surficial aquifer systems in the St. Johns River Water Management District.

Over a five- to 10-year period, many of the lakes in the Upper Etonia Creek Basin — in north-central Florida and comprising parts of Alachua, Bradford, Clay, and Putnam counties — experienced significant declines in lake stage, adversely affecting both recreational use and surrounding property values. Long-term hydrologic trends were investigated to help identify factors causing lake stage reductions.

The report addresses efforts to examine lake and surficial aquifer interactions for Lakes Lowry, Magnolia, Brooklyn, and Geneva, and to refine previously calculated water-budgets due to lake level declines in north-central Florida, and comprising parts of Alachua, Bradford, Clay, and Putnam counties.

This document was prepared to comply with the requirements of Section 373.207, Florida Statutes. It is the 11th annual report on the St. Johns River Water Management District’s abandoned artesian well inventory and work plan for controlling or plugging inventoried wells.

A time domain electromagnetic survey was performed at 24 sites in the St. Johns River Water Management District in May 1995. This report details field procedures and data quality control and analyses procedures.

Sixteen sediment/water interface cores from the area in and around the Blue Cypress Marsh Conservation Area, Upper St. Johns River Basin, were studied to assess the recent environmental history of the region. The sediment profiles were used to measure recent rates of bulk sediment accumulation, nutrient sequestering rates, rates of mercury deposition, and recent changes in the marsh flora.

This document was prepared to comply with the requirements of Section 373.207, Florida Statutes (1991). This the 12th 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 purpose of this study was to determine key factors that influence water usage among potato farms in the tri-county area of St. Johns, Putnam, and Flagler counties. Previous efforts have been limited to analyzing physical characteristics, such as soil type and plant age. This research effort also analyzes management and production techniques.

The Florida Natural Areas Inventory conducted this survey to locate, evaluate, and describe the natural communities of statewide and countywide significance within the Tiger Bay Study Area (TBSA), and particularly to provide information and descriptions of the most ecologically significant natural areas in the TBSA.

A north-central Florida regional groundwater flow model was developed to determine the magnitude and causes of the regional decline in groundwater levels in the Upper Floridan aquifer in an area extending westward from Duval County to Alachua County.

This is the final report of a project to determine desirable salinity conditions in the Sebastian River and the adjacent Indian River Lagoon. The St. Johns River Water Management District wanted to learn the nature of an “environmentally desirable and acceptable salinity regime” for these water bodies to calculate discharges needed to produce the desired salinity regime, or conclude that optimal discharges are beyond its control.

A time domain electromagnetic survey was performed at 19 sites in the St. Johns River Water Management District and one site in Georgia to provide a description of the vertical distribution (one-dimensional depth layering) of formation electrical resistivity and to verify water quality information obtained from wells in the test area.

The objective of this study was to investigate the effects of hydrology on certain aspects of the life history of the Florida apple snail (Pomacea paludosa), an important component of the marsh food chain and nearly the sole food source for the Florida snail kite (Rostrhamus sociabilis plumbeus). The study results assisted the St. Johns River Water Management District in writing a management plan for public property in the upper basin of the St. Johns River, which is an area of historical habitat for the species.

This study describes the effect of prescribed fire on the natural marsh communities within the Upper St. Johns River Basin. The objective of the study was to measure aboveground biomass and species composition prior to and following controlled burns in two marsh communities, one dominated by sawgrass (Cladium jamaicense) and the other dominated by maidencane (Panicum hemitomon).

Lakes Denham, Apopka, and Beauclair were sampled from January 1989 through June 1992 to assess the fish community of each lake and evaluate the response of gizzard shad removal on gamefish populations.

The study is part of an ongoing program to address the need for a long-term, environmentally sound water resources management policy. The primary purpose of this study is to provide a quantitative tool to assist with groundwater resources planning and management efforts in Seminole County.

This study was undertaken (1) to determine evapotranspiration and irrigation requirements of Florida blueberries, (2) to develop crop water use coefficients and to estimate crop water use from climate factors, and (3) to evaluate three irrigation scheduling methods.

A time domain electromagnetic survey was performed at 30 sites in the St. Johns River Water Management District to provide a description of the vertical distribution (one-dimensional depth layering) of formation electrical resistivity and to verify water quality information obtained from wells in the test area.

In 1989, a joint project was initiated between the St. Johns River Water Management District, Indian River County, and the University of Florida to study the effects of reclaimed wastewater on growth and development of citrus trees, yields, fruit quality, and soil nutrient levels and movement in flatwoods-type soils.

A geographic information system computer database was created containing the locations of each soil type in the main leatherleaf fern-producing counties (Lake, Putnam, Volusia) in Florida to determine the range of water-holding and nitrogen-leaching characteristics for the soils on which leatherleaf fern was being produced.

This report presents a compilation of data collected from all stations by the St. Johns River Water Management District as of the end of October 1993. These stations represent sites where rainfall, groundwater level, surface water level, lake stage, surface water discharge, groundwater quality, or spring water quality data are collected either electronically or manually.

This study was conducted to assess and quantify water quality-related conditions and to develop evaluation tools for assessing water quality problems of the lower St. Johns River. Volume 1 is an overall executive summary. Subsequent reports present the results of investigations.

Volume 2 of this study provides specialized analyses of the data collected from tide stations operated on the river during the federal/state cooperative effort in the late 1970s, for stations occupied more recently for National Ocean Service hydrographic surveys, and for a long-term historical dataset from the Long Branch, USE-DDP station in Jacksonville.

Volume 3 of this study was prepared to assist staff in decision making in use of existing control points or performing extension surveys of the geodetic networks. The manual is designed for the scientist or engineer responsible for hydrology studies of the lower St. Johns River and its tributaries.

Volume 5 of this study was prepared to provide a better understanding of sediment properties and dynamics and to document their importance in environmental degradation, to identify problems and data needs, and to develop guidelines for establishment of future detailed studies and management procedures.

Volume 6 of this study documents reviews of state-of-the-art hydrodynamic/salinity modeling of estuaries. An approach for developing a system of models and monitoring programs for the lower St. Johns River estuary is recommended.

Volume 7 of this study is an overview of the workshop held asthe final task: “A Lower St. Johns River Workshop — Sediments, Hydrodynamics, Water Quality, and Related Issues.”

This report covers the data acquisition, processing, interpretation, and results of a time domain electromagnetic survey performed at 17 sites in the St. Johns River Water Management District and one site in southeast Georgia.

This report covers the integration of time domain electromagnetic soundings, made in Seminole County, Florida, during July 1992 to update depth contour maps of the 5,000-milligrams per liter (mg/L) and 250-mg/L isochlors previously constructed for the St. Johns River Water Management District.

This study examines the effects of water level fluctuations on above- and below-ground plant community structure and soil and plant tissue nutrients at Hopkins Prairie, a wet prairie in the Ocala National Forest, Fla.

The primary purpose of this study was to provide the means for regional analysis of groundwater resources in eastern Orange County to guide planning and management efforts, with major emphasis on the Floridan aquifer system.

The purpose of this study was to assess the possibility of buying land in the Nassau River and Lower St. Johns River basins as a means of protecting lands of high hydrologic and ecological value. KBN developed a ranking system, then ranked based on its value for protecting water resources.

In April 1990, the St. Johns River Water Management District Governing Board directed staff to begin rulemaking to develop Econlockhatchee Basin-specific stormwater management rule criteria consistent with River Task Force recommendations. From these recommendations, two (II.B and II.E) specifically address water quantity/quality issues and require an estimate of the overall water budget for the entire basin.

KBN Engineering and Applied Sciences developed a wetlands management strategy for the St. Marys River Basin to provide background information about the physical and biological character of the region, examine existing regulatory and management programs in place, assess land use trends, and propose recommendations for more effective long-term management.

The purpose of this vegetation study was to document natural recruitment and successional patterns over the Sunnyhill Farm site and relate environmental variables with vegetation and succession.

This report documents the evaluation of the impact of hydrilla on the water supply potential of Lake Washington. Hydrilla verticillata is the most troublesome aquatic weed in the St. Johns River Water Management District in terms of acres of surface water infested, rate of expansion, environmental and economic impacts, and financial resources necessary to manage this exotic aquatic weed at the city of Melbourne’s water supply source, Lake Washington.

Water management districts require that new developments have a comprehensive stormwater management system to ensure that stormwater runoff is being effectively treated. The focus of this study is on retention systems. Field data were used to evaluate and recommend hydrogeologic characterization techniques and design methodologies for computing the time of percolation of impounded stormwater runoff.

A pilot program was initiated to determine the usefulness of an Index of Biological Integrity (IBI) in the lower St. Johns River. The IBI is a numerical index, based on numbers and varieties of fish present in an area, employed as a biological complement to chemistry measurements for assessing water quality.

Field and laboratory investigations were conducted in DeBary, Florida, to evaluate the hydraulic and water quality characteristics of a detention pond with filtration system. Pilot scale experiments were conducted to evaluate the effects of filer media, filter configurations, and sod cover on hydraulic performance and pollutant attenuation of filter systems.

The proceedings of a 1992 workshop are incorporated into this publication, outlining consensus on how to maintain and enhance critical submerged aquatic vegetation in the Indian River Lagoon system.