Glossary

1-in-10 Year Level of Certainty Probability that the needs for reasonable-beneficial uses of water will be fully met during a 1-in-10 year drought.

Acre-foot The volume of water that covers one acre to a depth of one foot; 43,560 cubic feet; 1,233.5 cubic meters; 325,872 gallons.

AFSIRS Agricultural Field Scale Irrigation Requirements Simulation.

Alternative Water Supply A supply of water that has been reclaimed after one or more public supply, municipal, industrial, commercial or agricultural uses, or a supply of stormwater, or brackish or salt water, that has been treated in accordance with applicable rules and standards sufficient to supply the intended use.

Agricultural Field Scale Irrigation Requirements Simulation (AFSIRS) A simple water budget model for estimating irrigation demands that estimates demand based on basin specific data.

Agricultural Self-Supplied Water Demand The water used to irrigate crops, to water cattle and for aquaculture (e.g., fish production) that is not supplied by a public water supply utility.

Anoxic Denotes the absence of oxygen

Aquatic Preserve Water bodies that are set aside by the state to be maintained in essentially natural or existing condition, for protection of fish and wildlife and public recreation so that their aesthetic biological and scientific values may endure for the enjoyment of future generations.

Aquifer A portion of a geologic formation or formations that yield water in sufficient quantities to be a supply source.

Aquifer Storage and Recovery (ASR) The injection of fresh water into a confined saline aquifer during times when supply exceeds demand (wet season), and recovering it during times when there is a supply deficit (dry season).

Aquifer System A heterogeneous body of intercalated permeable and less permeable material that acts as a water-yielding hydraulic unit of regional extent.

Artesian When groundwater is confined under pressure greater than atmospheric pressure by overlying relatively impermeable strata.

ASR Aquifer Storage and Recovery.

Available Supply The maximum amount of reliable water supply including surface water, groundwater and purchases under secure contracts.

Average Daily Demand A water system's average daily use based on total annual water production (total annual gallons or cubic feet divided by 365).

Average Irrigation Requirement Irrigation requirement under average rainfall as calculated by the District's modified Blaney-Criddle model.

Average Rainfall Year A year having rainfall with a 50 percent probability of being exceeded over a twelve-month period.

AWWA American Water Works Association.

Backpumping The practice of actively pumping water leaving an area back into a surface water body.

Baseline Condition (see Reference Condition )

Basin (Groundwater) A hydrologic unit containing one large aquifer or several connecting and interconnecting aquifers.

Basin (Surface Water) A tract of land drained by a surface water body or its tributaries.

Basis of Review (BOR) From the District's publication, Basis of Review for Water Use Permit Applications within the South Florida Water Management District . Read in conjunction with Chapters 40E-2 and 40E-20, tge Basis of Review further specifies the general procedures and information used by District staff for review of water use permit applications with the primary goal of meeting District water resource objectives.

BEBR Bureau of Economic and Business Research

Best Management Practices (BMPs) Agricultural management activities designed to achieve an important goal, such as reducing farm runoff or optimizing water use.

Biochemical Oxygen Demand (BOD) The amount of dissolved oxygen required to meet the metabolic needs of aerobic microorganisms in water rich in organic matter, such as sewage. Also known as Biological Oxygen Demand.

Biscayne Aquifer A portion of the Surficial Aquifer System, which provides most of the fresh water for public water supply and agriculture within Miami-Dade, Broward and southeastern Palm Beach County. It is highly susceptible to contamination due to its high permeability and proximity to land surface in many locations.

Blaney-Criddle A formula to calculate evapotranspiration (ET) based on mean temperature and number of daylight hours. The Water Supply Department allocates water using a version of the Blaney-Criddle that employs months as time increments. The 'Modified Blaney-Criddle' is a variation of Blaney-Criddle, which multiplies the ET from Blaney-Criddle by a coefficient that relates mean air temperature to the growth stage of a crop. Additionally, effective rainfall is calculated using the mean temperature and hours of daylight, the Blaney-Criddle ET, average monthly rainfall and a soil factor. Further calculations consider average rainfall to drought rainfall (1-in-10 year drought). The difference between monthly drought effective rainfall and monthly ET becomes the basis for water allocations.

BMP Best Management Practice.

BOD Biochemical Oxygen Demand.

BOR Basis of Review.

Boulder Zone A highly transmissive, cavernous zone of limestone within the lower Floridan Aquifer.

Brackish Water with a chloride level greater than 250 mg/L and less than 19,000 mg/L.

C&SF Project Central and Southern Florida Flood Control Project.

C&SF Restudy Central and Southern Florida Project Comprehensive Review Study.

Capacity Capacity represents the ability to treat, move or reuse water. Typically capacity is expressed in million gallons per day (MGD).

Central and Southern Florida Project Comprehensive Review Study (C&SF Restudy) A five-year study effort that looked at modifying the current C&SF Project to restore the greater Everglades and South Florida ecosystem while providing for the other water related needs of the region. The study concluded with the Comprehensive Plan being presented to the Congress on July 1, 1999. The recommendations made within the Restudy, that is, structural and operational modifications to the C&SF Project, are being further refined and will be implemented in the Comprehensive Everglades Restoration Plan (CERP).

Central and Southern Florida Flood Control Project (C&SF Project) A complete system of canals, storage areas and water control structures spanning the area from Lake Okeechobee to both the east and west coasts and from Orlando south to the Everglades. It was designed and constructed during the 1950s by the United States Army Corps of Engineers (USACE) to provide flood control and improve navigation and recreation.

CERP Comprehensive Everglades Restoration Plan

Clastic Rock or sediment composed of individual grains or fragments from physical breakdown of a larger mass, which have been transported from its place of origin.

Commercial and Industrial Self-Supplied Water Demand Water used by commercial and industrial operations withdrawing over 0.1 million gallons per day from individual, on-site wells.

Comprehensive Everglades Restoration Plan (CERP) The implementation of recommendations made within the Restudy, that is, structural and operational modifications to the C&SF Project are being further refined and will be implemented through this plan.

Cone of Depression Depression of the water table or potentiometric surface showing the variation of drawdown with distance due to pumping from a well, wellfield, or surface water body within its area of influence.

Cone of Influence The area around a producing well that will be affected by its operation.

Confined Aquifer Water bearing stratum of permeable rock, sand or gravel overlaid by a thick, impermeable stratum.

Conservation (see Water Conservation )

Conservation Rate Structure A water rate structure that is designed to conserve water. Examples of conservation rate structures include but are not limited to, increasing block rates, seasonal rates and quantity-based surcharges.

Consumptive Use Use that reduces an amount of water in the source from which it is withdrawn.

Consumptive Use Permit (CUP) A permit issued by the SFWMD under authority of Chapter 40E-2, F.A.C., allowing withdrawal of water for consumptive use.

Control Structure A man-made structure designed to regulate the level/flow of water in a canal or water body (e.g., weirs, dams).

Critical Water Supply Problem Areas ( see Water Resource Caution Areas).

CUP Consumptive User Permit.

Cynobacteria Blue-green algae.

Demand The quantity of water needed to be withdrawn to fulfill a requirement.

Denitrification Reduction of nitrates or nitrites commonly by bacteria (as in soil) that usually results in the escape of nitrogen into the air.

Desalination A process that treats saline water to remove chlorides and dissolved solids, resulting in the production of fresh water.

Dissolved Oxygen - The concentration of oxygen dissolved in water, sometimes expressed as percent saturation, where saturation is the maximum amount of oxygen that theoretically can be dissolved in water at a given altitude and temperature.

District South Florida Water Management District.

District Water Management Plan (DWMP) Regional water resource plan developed by the District under Ch. 373.036, F. S.

Districtwide Water Supply Assessment (DWSA) This document includes water demand assessments and projections, and descriptions of the surface water and groundwater resources within each of the SFWMD's four planning areas.

Domestic Self-Supplied (DSS) Water Demand ( Same as Residential Self-Supplied Water Demand ) The water used by households whose primary source of water is private wells and water treatment facilities with pumpages of less than 0.10 million gallons per day.

Domestic Use Use of water for household purposes of drinking, bathing, cooking or sanitation.

Drainage District A locally constituted drainage, water management or water control district that is created by special act of the legislature and authorized under Ch. 298 F.S., to constrict, complete, operate, maintain, repair and replace any and all works necessary to implement an adopted water control plan.

Drawdown The vertical distance a water level is lowered resulting from a withdrawal at a given point.

DSS Domestic Self-Supplied.

DWMP District Water Management Plan.

DWSA Districtwide Water Supply Assessment.

EAA Everglades Agricultural Area.

Effective Rainfall The portion of rainfall that infiltrates the soil and is stored for plant use in the crop root zone, as calculated by the modified Blaney-Criddle model.

Electrodialysis Dialysis that is conducted with the aid of an electromotive force applied to electrodes adjacent to both sides of the membrane.

Environmental Resource Permit (ERP) A permit issued by the SFWMD under authority of Chapter 40E-4 F.A.C. to ensure that land development projects do not cause adverse environmental, water quality or water quantity impacts.

ERP Environmental Resource Permit.

Estuary A water passage where the ocean or sea meets a river.

Eutrophication The gradual increase in nutrients in a body of water. Natural eutrophication is a gradual process, but human activities may greatly accelerate the process.

Evapotranspiration (ET) Water losses from the surface of water and soils (evaporation) and plants (transpiration).

Everglades Agricultural Area (EAA) The area of histosols (muck) south of Lake Okeechobee, which is used for agricultural production.

Everglades Protection Area This area is comprised of the Water Conservation Areas and Everglades National Park.

Exotic Plant Species A nonnative species that tends to outcompete native species and become quickly established, especially in areas of disturbance or where the normal hydroperiod has been altered.

F.A.C. Florida Administrative Code.

FAS Floridan Aquifer System.

FDACS Florida Department of Agricultural and Consumer Services.

FDEP Florida Department of Environmental Protection.

Fiscal Year (FY) The South Florida Water Management District's fiscal year begins on October 1 and ends on September 30 the following year.

Flatwoods (Pine) Natural communities that occur on level land and are characterized by a dominant overstory of slash pine. Depending on soil drainage characteristics and position in the landscape, pine flatwoods habitats can exhibit xeric to moderately wet conditions.

Florida Administrative Code (F.A.C.) The Florida Administrative Code is the official compilation of the administrative rules and regulations of state agencies.

Florida Department of Agricultural and Consumer Services (FDACS) FDACS communicates the needs of the agricultural industry to the Florida Legislature, the FDEP, and the water management districts, and ensures participation of agriculture in the development and implementation of water policy decisions. FDACS also oversees Florida's soil and water conservation districts, which coordinate closely with the federal Natural Resources Conservation Service (NRCS).

Florida Department of Environmental Protection (FDEP) The SFWMD operates under the general supervisory authority of the FDEP, which includes budgetary oversight.

Florida Statutes (F.S.) The Florida Statutes are a permanent collection of state laws organized by subject area into a code made up of titles, chapters, parts and sections. The Florida Statutes are updated annually by laws that create, amend or repeal statutory material.

Florida Water Plan State-level water resource plan developed by the FDEP under Section 373.036 F.S.

Floridan Aquifer System (FAS) A highly-used aquifer system composed of the Upper Floridan and Lower Floridan Aquifers. It is the principal source of water supply north of Lake Okeechobee and the upper Floridan Aquifer is used for drinking water supply in parts of Martin and St. Lucie Counties. From Jupiter to south Miami, water from the Floridan Aquifer System is mineralized (total dissolved solids are greater than 1,000 mg/L) along coastal areas and in southern Florida.

Flow The actual amount of water flowing by a particular point over some specified time. In the context of water supply, flow represents the amount of water being treated, moved or reused. Flow is frequently expressed in millions of gallons per day (MGD).

Food Web The totality of interacting food chains in an ecological community.

F.S. Florida Statutes.

FY Fiscal Year.

Geographic Information Systems (GIS) The abstract representation of natural (or cultural) features of a landscape into a digital database, geographic information system.  

Governing Board Governing Board of the South Florida Water Management District.

GPD Gallons per day.

GPM Gallons per minute.

Groundwater Water beneath the soil surface, whether or not flowing through known and definite channels.

Groundwater Heads Elevation of water table.

Harm The temporary loss of water resource functions, as defined for consumptive use permitting in Chapter 40E-2, F.A.C., which results from a change in surface or groundwater hydrology and takes a period of one to two years of average rainfall conditions to recover.

Hydropattern The pattern of inundation or saturation of an ecosystem.

Hydroperiod The frequency and duration of inundation or saturation of an ecosystem. In the context of characterizing wetlands, the term hydroperiod describes that length of time during the year that the substrate is either saturated or covered with water.

IAS Intermediate Aquifer System.

Incremental Simulations Model simulations performed to understand how the system would perform with partial completion of the Restudy projects and if the ability to meet the 1-in-10 year level of certainty criteria improves over time. Incremental years selected were, 2005, 2010 and 2015.

Indian River Lagoon Extending for 156 miles from north of Cape Canaveral to Stuart along the east coast of Florida, this lagoon is America's most diverse estuary, home to more than 4,000 plant and animal species.

Indicator Region A grouping of model grid cells within the SFWMM consisting of similar vegetation cover and soil type. By grouping cells, the uncertainty of evaluating results from a single two by two, square mile grid cell that represents a single water management gage is reduced.

Infiltration The movement of water through the soil surface into the soil under the forces of gravity and capillarity.

Inorganic Involving neither organic life nor the products of organic life; relating to or composed of chemical compounds not containing hydrocarbon groups.

Institute of Food and Agricultural Sciences (IFAS) Agricultural branch of the University of Florida that performs research, education and extension.

Intermediate Aquifer System (IAS) This aquifer system consists of five zones of alternating confining and producing units. The producing zones include the Sandstone and mid-Hawthorn Aquifers.

Irrigation The application of water to crops and other plants by artificial means.

Irrigation Audit A procedure in which an irrigation systems application rate and uniformity are measured.

Irrigation Efficiency The average percent of total water pumped or delivered for use that is delivered to the root zone of a plant.

Irrigation Uniformity A measure of the spatial variability of applied or infiltrated water over the field.

Lagoon A body of water separated from the ocean by barrier islands, with limited exchange with the ocean through inlets.

Lake Okeechobee This lake measures 730 square miles and is the second largest freshwater lake wholly within the United States.

Lake Okeechobee SWIM Planning Area The major basins that are direct tributaries to Lake Okeechobee, including those basins that are hydrologically upstream and/or from which water is presently released or pumped into the lake on a regular basis.

Leakance Movement of water between aquifers or aquifer systems.

Leak Detection Systematic method of using listening equipment to survey the distribution system, identify leak sounds, and pinpoint the exact locations of hidden underground leaks.

Levee An embankment to prevent flooding or a continuous dike or ridge for confining the irrigation areas of land to be flooded.

Level of Certainty Probability that the demands for reasonable-beneficial uses of water will be fully met for a specified period of time (generally taken to be one year) and for a specified condition of water availability (generally taken to be a drought event of a specified return frequency).

Littoral Of, relating to, situated or growing on or near a shore.

Load Concentration times flow.  

Marsh A frequently or continually inundated non-forested wetland characterized by emergent herbaceous vegetation adapted to saturated soil conditions.

MCL Maximum contaminant level.

MFL Minimum flow and level.

MGD Millons of gallons per day.

Mg/L Milligrams per liter.

MGY Millions of gallons per year.

Microfiltration A membrane separation process in which particles greater than about 20 nanometers in diameter are screened out of a liquid in which they are suspended.

Microirrigation The application of water directly to or very near to the soil surface in drops, small streams or sprays.

Microorganism A microscopic organism, including bacteria, protozoans, yeast, viruses and algae.

MIKE SHE An integrated surface water/groundwater model, which includes a module for estimating supplemental irrigation requirements based upon land use, soil type, crop type, rainfall and evapotranspiration.

MIL Mobile irrigation laboratory.

Minimum Flow and Level (MFL) The point at which further withdrawals would cause significant harm to the water resources/ecology of the area.

Mobile Irrigation Laboratory (MIL) A vehicle furnished with irrigation evaluation equipment which is used to carry out on-site evaluations of irrigation systems and to provide recommendations on improving irrigation efficiency.

MODFLOW A fine-scale model code created by the U.S. Geological Survey. The District uses it for subregional and groundwater modeling.

Mutagen An agent that raises the frequency of mutation above the spontaneous or background rate; a compound having the ability to produce a change in the DNA of a cell.

National Geodetic Vertical Datum (NGVD) A nationally established reference for elevation data.

Native Nuisance Species Native plant species that spread rapidly under disturbed conditions and displace more desirable plant communities.

Natural Resources Conservation Service (NRCS) An agency of the U.S. Department of Agriculture (USDA) that provides technical assistance for soil and water conservation, natural resource surveys and community resource protection. Formerly the U.S. Soil Conservation Service (SCS).

NGVD National Geodetic Vertical Datum.

Nonpoint source Source originating over broad areas, such as areas of fertilizer and pesticide application or leaking sewer systems, rather than from discrete points.

NRCS Natural Resources Conservation Service.

Organics Involving organic or products of organic life; relating to or composed of chemical compounds containing hydrocarbon groups.

Pelagic Zone Open water zone.

Per Capita Use Total use divided by the total population served.

Performance Measure Performance measures quantify how well or how poorly an alternative meets a specific objective. Good performance measures are quantifiable, have a specific target, indicate when a target has been reached, and measure the degree to which the goal has been met.

Permeability Defines the ability of a substrate to transmit fluid.

Phytoplankton The floating, usually minute, plant life of a body of water.

PLRG Pollutant Load Reducation Goal.

Point Source Any discernible, confined and discrete conveyance from which pollutants are or may be discharged, including, but not limited to, any pipe, ditch, channel, tunnel, conduit, well, discrete fissure, container, rolling stock, concentrated animal feeding operation or vessel or other floating craft. This term does not include agricultural stormwater discharges and return flows from irrigated agriculture.

Pollutant Load Reduction Goal (PLRG) Targeted reduction in pollutant loading to a water body needed to achieve watershed management goals.

Potable Water Water that is safe for human consumption. The maximum chloride concentration is 250 milligrams/liter.

Potentiometric Head The level to which water will rise when a well is pierced in a confined aquifer.

Potentiometric Surface An imaginary surface representing the total head of groundwater.

Process Water Water used for nonpotable industrial usage, e.g., mixing cement.

Public Water Supply (PWS) Utilities that provide potable water for public use.

Public Water Supply Demand All potable water supplied by regional water treatment facilities with pumpage of 0.5 million gallons per day or more to all customers, not just residential.

Rapid-Rate Exfiltration Basin An artificial impoundment that provide for fluid losses through percolation/seepage, as well as through evaporative losses.

Reasonable-Beneficial Use Use of water in such quantity as is necessary for economic and efficient utilization for a purpose and in a manner that is both reasonable and consistent with the public interest.

Reclaimed Water Water that has received at least secondary treatment and basic disinfection and is reused after flowing out of a domestic wastewater treatment facility.

RECOVER A comprehensive monitoring and adaptive assessment program formed to perform the following for the Comprehensive Everglades Restoration Program: restoration, coordination and verification.

Recreational Self-Supplied Water Demand The water used for landscape and golf course irrigation. The landscape subcategory includes water used for parks, cemeteries and other irrigation applications greater than 0.1 million gallons per day. The golf course subcategory includes those operations not supplied by a public water supply or regional reuse facility.

Regional Water Supply Plan (RWSP) Detailed water supply plan developed by the District under Section 373.0361, F.S. ., providing an evaluation of available water supply and projected demands, at the regional scale. The planning process projects future demand for 20 years and develops strategies to meet identified needs.

Reservations of Water (see Water Reservations ).

Reservoir A man-made or natural water body used for water storage.

Residential Self-Supplied Water Demand ( Same as Domestic Self-Supplied Water Demand ) The water used by households whose primary source of water is private wells and water treatment facilities with pumpages of less than 0.5 million gallons per day.

Restudy Shortened name for C&SF Restudy.

Retrofit The replacement of existing equipment with equipment of higher efficiency.

Retrofitting The replacement of existing water fixtures, appliances and devices with more efficient fixtures, appliances and devices for the purpose of conservation.

Reuse The deliberate application of reclaimed water for a beneficial purpose. Criteria used to classify projects as "reuse" or "effluent disposal" are contained in Rule 62-610.810, F.A.C.

Reverse Osmosis (RO) A membrane process for desalting water using applied pressure to drive the feedwater (source water) through a semipermeable membrane.

RO Reverse Osmosis.

Rolling (Moving) Average The arithmetic average of a sequence of data within a data set moved and calculated sequentially to smooth the data and reveal trends (e.g., five-year rolling total phosphorus concentrations).

RWSP Regional Water Supply Plan.

Saline Water or Saltwater Interface The hypothetical surface of chloride concentration between fresh water and seawater where the chloride concentration is 250 mg/L at each point on the surface.

Saline Water or Saltwater Intrusion This occurs when more dense saline water moves laterally inland from the seacoast, or moves vertically upward, to replace fresher water in an aquifer.

SAS Surficial Aquifer System.

Seawater Water which has a chloride concentration equal to or greater than 19,000 milligrams per liter.

Self-Supplied The water used to satisfy a water need, not supplied by a public water supply utility.

Seepage Irrigation Irrigation that conveys water through open ditches. Water is either applied to the soil surface (possibly in furrows) and held for a period of time to allow infiltration, or is applied to the soil subsurface by raising the water table to wet the root zone.

Semi-confining Layers Layers with little or no horizontal flow, restricting the vertical flow of water from one aquifer to another. The rate of vertical flow is dependent on the head differential between the aquifers, as well as the vertical permeability of the sediments in the semi-confining layer.

Sensitivity Analysis An analysis of alternative results based on variations in assumptions (a "what if " analysis).

Serious Harm The long-term loss of water resource functions, as addressed in Chapters 40E-21 and 40E-22, F.A.C., resulting from a change in surface or groundwater hydrology.

SFWMM South Florida Water Management Model.

SFWMD South Florida Water Management District.

Significant Harm The temporary loss of water resource functions, which result from a change in surface or groundwater hydrology, that takes more than two years to recover, but which is considered less severe than serious harm. The specific water resource functions addressed by a MFL and the duration of the recovery period associated with significant harm are defined for each priority water body based on the MFL technical support document.

SJRWMD St. Johns River Water Management District.

Slough A channel in which water moves sluggishly, or a place of deep muck, mud or mire. Sloughs are wetland habitats that serve as channels for water draining off surrounding uplands and/or wetlands.

South Florida Water Management Model (SFWMM) An integrated surface water- groundwater model that simulates the hydrology and associated water management schemes in the majority of South Florida using climatic data from January 1, 1965, through December 31, 1995. The model simulates the major components of the hydrologic cycle and the current and numerous proposed water management control structures and associated operating rules. It also simulates current and proposed water shortage policies for the different subregions in the system.

SPF Standard Flood Project.

STA Stormwater treatment area.

Stage The water surface elevation of a water body.

Standard Project Flood (SPF) A mathematically derived set of hydrologic conditions for a region that defines the water levels that can be expected to occur in a basin during an extreme rainfall event, taking into account all pertinent conditions of location, meteorology, hydrology and topography.

Storm Water Surface water resulting from rainfall runoff that does not percolate into the ground or evaporate.

Stormwater Treatment Area (STA) A system of water quality treatment wetlands that use natural biological processes to reduce levels of nutrients and pollutants from surface water runoff.

Subregional Groundwater Model A computer model that is used to simulate impacts on a smaller scale than the SFWMM, such as effects within public water supply service areas and impacts of individual wellfields.

Subsidence The loss of soil-bulk caused by the oxidation, decomposition and shrinkage of organic material.

Supply-side Management The conservation of water in Lake Okeechobee to ensure that water demands are met while reducing the risk of serious or significant harm to natural systems.

Surface Water Water that flows, falls or collects above the soil or substrate surface.

Surface Water Improvement and Management (SWIM) Plan A plan prepared pursuant to Chapter 373, F.S.

Surficial Aquifer System (SAS) Often the principal source of water for urban uses within certain areas of south Florida. This aquifer is unconfined, consisting of varying amounts of limestone and sediments that extend from the land surface to the top of an intermediate confining unit.

Swamp A frequently or continuously inundated forested wetland.

SWFWMD Southwest Florida Water Management District.

SWIM Surface Water Improvement and Management.

Thermoelectric Self-Supplied Water Demand The difference in the amount of water withdrawn by electric power generating facilities for cooling purposes and the water returned to the hydrologic system near the point of withdrawal.

THM Trihalomethane.

Tidal Rivers Water bodies that receive freshwater from areas other than runoff (from the upstream watershed), are flushed to some extent during a tidal cycle, and are subject to saltwater intrusion from downstream areas.

TMDL Total maximum daily load.

Total Maximum Daily Load (TMDL) The level of loading to a body of water that will protect uses and maintain compliance with water quality standards (defined in the Clean Water Act).

Total Trihalomethane (TTHM) A sum of chloroform, bromodichloromethane, dibromochloromethane and bromoform.

Trophic Level One of the hierarchical strata of a food web characterized by organisms which are the same number of steps removed from the primary producers

Transmissivity A term used to indicate the rate at which water can be transmitted through a unit width of aquifer under a unit hydraulic gradient. It is a function of the permeability and thickness of the aquifer, and is used to judge its production potential.

Trihalomethanes (THMs) Any of several synthetic organic compounds formed when chlorine combines with organic materials in water during the disinfection process.

TTHM Total Trihalomethanes.

Turbidity The measure of suspended material in a liquid.

UIC Underground injection control.

Ultralow-volume Plumbing Fixtures Water-conserving plumbing fixtures that meet the standards at a test pressure of 80 pounds per square inch (psi) listed below.

• Toilets - 1.6 gallons/flush
• Shower Heads - 2.5 gallons/minute
• Faucets - 2.0 gallons/minute

Underground Injection Control (UIC) A program required in each state by a provision of the Safe Drinking Water Act (SDWA) for the regulation of Injection Wells , including a permit system. An applicant must demonstrate that the well has no reasonable chance of adversely affecting the quality of an underground source of drinking water before a permit is issued.

Upconing Process by which saline water underlying fresh water in an aquifer rises upward into the freshwater zone as a result of pumping water from the freshwater zone.

Uplands An area with a hydrologic regime that is not sufficiently wet to support vegetation typically adapted to life in saturated soil conditions; nonwetland.

Valued Ecosystem Component (VEC) A resource-based management strategy similar to a program developed by the EPA as part of the National Estuary Program. For the purposes of this study, the VEC approach is based on the concept that management goals for the Northwest Fork of the Loxahatchee River can best be achieved by providing suitable environmental conditions that will support certain key species, or key groups of species, that inhabit the system.

VEC Valued ecosystem component.

Vertical Migration The vertical movement of oil, gas, contaminants, water or other liquids through porous and permeable rock.

Wastewater The waterborne discharge from residences, commercial buildings, industrial plants and institutions together with any groundwater, surface runoff or leachate that may be present.

Water Budget An accounting of total water use or projected water use for a given location or activity.

Water Conservation Reducing the demand for water through activities that alter water use practices, e.g., improving efficiency in water use, and reducing losses of water, waste of water and water use.

Water Conservation Areas (WCAs) Part of the original Everglades ecosystem that is now diked and hydrologically controlled for flood control and water supply purposes. These are located in the western portions of Miami-Dade, Broward and Palm Beach Counties, and preserve a total of 1,337 square miles, or about 50 percent of the original Everglades.

Water Control District (see Drainage District )

Water Reservations State law on water reservations, in Section 373.223(4), F.S., defines water reservations as follows: "The governing board or the department, by regulation, may reserve from use by permit applicants, water in such locations and quantities, and for such seasons of the year, as in its judgment may be required for the protection of fish and wildlife or the public health and safety. Such reservations shall be subject to periodic review and revision in the light of changed conditions. However, all presently existing legal uses of water shall be protected so long as such use is not contrary to the public interest."

Water Resource Caution Areas Areas that have existing water resource problems or are placed where water resource problems are projected to develop during the next 20 years (previously referred to as critical water supply problem areas).

Water Resource Development The formulation and implementation of regional water resource management strategies, including the collection and evaluation of surface water and groundwater data; structural and nonstructural programs to protect and manage the water resources; the development of regional water resource implementation programs; the construction, operation and maintenance of major public works facilities to provide for flood control, surface and underground water storage and groundwater recharge augmentation; and related technical assistance to local governments and to government- owned and privately-owned water utilities.

Watershed The drainage area from which all surface water drains to a common receiving water body system.

Watershed Management Goals Goals that encompass any one or all of the major water management district responsibilities: flood protection, water supply, water quality and environmental system protection and enhancement. The goals provide the general direction for developing cohesive strategies to manage water resources within a drainage basin, subbasin or segment of a drainage basin or subbasin.

Water Resource Caution Areas Areas that have existing water resource problems or are placed where water resource problems are projected to develop during the next 20 years (previously referred to as Critical Water Supply Problem Areas).

Water Shortage Declaration If there is a possibility that insufficient water will be available within a source class to meet the estimated present and anticipated user demands from that source, or to protect the water resource from serious harm, the governing board may declare a water shortage for the affected source class. (Rule 40E- 21.231, F.A.C.) Estimates of the percent reduction in demand required to match available supply is required and identifies which phase of drought restriction is implemented. A gradual progression in severity of restriction is implemented through increasing phases. Once declared, the District is required to notify permitted users by mail of the restrictions and to publish restrictions in area newspapers.

Water Supply Development The planning, design, construction, operation and maintenance of public or private facilities for water collection, production, treatment, transmission or distribution for sale, resale or end use.

WCA Water Conservation Area.

Weir A barrier placed in a stream to control the flow and cause it to fall over a crest. Weirs with known hydraulic characteristics are used to measure flow in open channels.

Wetland Drawdown Study Research effort by the South Florida Water Manage-ment District to provide a scientific basis for developing wetland protection criteria for water use permitting.

Wetlands Areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support a prevalence of vegetation typically adapted for life in saturated soil conditions.

Wild and Scenic River A river as designated under the authority of the of Public Law 90-542, the wild an Scenic Rivers Act as amended, as a means to preserve selected free-flowing rivers in their natural condition and protect the water quality of such rivers. The Loxahatchee River was federally designated as the first Wild and Scenic River in Florida on May 17, 1985.

Xeriscape TM Landscaping that involves seven principles: proper planning and design; soil analysis and improvement; practical turf areas; appropriate plant selection; efficient irrigation; mulching; and appropriate maintenance.

Zooplankton The passively floating or weakly swimming, usually minute, animal life of a body of water.