BEST MANAGEMENT PRACTICES (BMPs) are activities or structural improvements that help to reduce the quantity and improve the quality of stormwater runoff. Initiation of a BMP also requires the development of a monitoring program to assess its effectiveness.
CAPITAL IMPROVEMENT PROGRAM (CIP) is a program adopted by a government agency which prioritizes individual capital improvement projects which are to be constructed over a certain period of time, based upon funding which has been, or will be, allocated.
CHANNEL means that portion of a WATERCOURSE, either natural or modified by man, that conveys the majority of STORM WATER within its primary flow boundaries. The use of the term CHANNEL often implies a WATERCOURSE that is no longer in its natural condition.
CITY means the incorporated limits of the City of Tucson, Arizona.
COMBINATION ALTERNATIVES means the combination of individual features inherent to two or more STORMWATER MANAGEMENT ALTERNATIVES (e.g., Structural, Non- Structural), in whatever proportions are deemed appropriate, to produce a hybrid alternative. Where an assessment of stormwater needs encompasses a larger WATERSHED, different alternatives may be applicable for different reaches, or areas, along affected WATERCOURSES, thus producing a COMBINATION ALTERNATIVE for the specific watershed under study.
CONVEYANCE is the physical process of water moving from one location to another.
CULVERT is a short, closed conduit employed for the purpose of passing stormwater runoff under an embankment, usually a roadway. A rectangular or square concrete structure is commonly referred to as a box culvert .
DETENTION refers to a type of STORMWATER SYSTEM which employs a reservoir, or other similar measures, as a means of delaying the downstream progress of stormwater runoff in a controlled manner. This is generally accomplished through the combined use of temporary storage areas and a metered outlet device which reduces downstream runoff peaks, thereby causing a lengthening of the duration of stormwater outflow.
DISPERSED FLOW is characterized by wide, shallow, "sheet-flow" runoff conditions, usually found in areas where no CHANNELS or well-defined drainageways exist to serve as the primary runoff-conveyance systems.
ERZ is an abbreviation for "Environmental Resource Zone", which is part of the City of Tucson Zoning Code (Section 23-472) derived from Ordinance 7450, adopted July 3, 1990. The ERZ is intended to protect critical RIPARIAN habitat in certain mapped areas and resource corridors.
FLOOD is a temporary rise in flow or stage of any WATERCOURSE, or stormwater conveyance system, that results in stormwater runoff exceeding its normal flow boundaries and inundating adjacent, normally dry areas.
FLOOD CONTROL refers to those specific regulations and practices that reduce or prevent the damage that is caused by stormwater runoff.
FLOOD INSURANCE is federally subsidized insurance made available through the National Flood Insurance Program for residents of communities that participate in the program. FLOOD INSURANCE, initially instituted to mitigate the cost to the Federal government for providing disaster assistance in cases of flooding, protects homeowners or renters against large monetary losses resulting from flood damages.
FLOOD PLAIN means any land area susceptible to inundation by STORM WATER from any source. The FLOOD PLAIN is often defined as those normally dry lands adjoining or near the channel of a WATERCOURSE which have been, or may be, covered by stormwater runoff.
FLOODPLAIN MANAGEMENT is the regulation of land which is subject to inundation by STORM WATER through application of the full range of codes, ordinances, and other regulations relating to the use of those lands, and the development thereupon, that are affected by stormwater runoff.
FLOODPLAIN REGULATIONS are those codes, ordinances, and regulations adopted by government relating to the use of those lands, and the development thereupon, that lie within any regulatory FLOOD PLAIN.
FLOODPRONE LAND ACQUISITION is the systematic and prioritized purchase of floodprone land by a government agency. The purchase of floodprone land removes the land from private ownership; which, in turn, eliminates future flood damages to existing development or prevents development on the floodprone land.
FLOODPROOFING consists of improvements to or near a structure for the purpose of preventing floodwaters from entering the structure. FLOODPROOFING, usually designed to protect a structure from the 100-year flood, can be included in the design of new buildings or retrofitted into existing buildings.
HIGHLY URBAN WATERSHEDS generally contain six or more houses per acre, and include commercial, industrial and multiple dwelling uses, with extensive drainage improvements. Impervious surfaces generally cover approximately 70 percent, or greater, of the watershed area.
HEC-1 is a rainfall/runoff computer program developed by the U.S. Army Corps of Engineers; and is utilized to determine peak discharges, flood volumes, and flood hydrographs.
HYDROLOGIC UNITS are the six general WATERSHEDS, or hydrologically similar areas, defined within the STUDY AREA for the TSMS, Phase II, STORMWATER MASTER PLAN. The six HYDROLOGIC UNITS correspond to the six Basins identified during Phase I of the TSMS.
MODELING means a mathematical or physical simulation, the former often accomplished with the aid of a computer, that is applied to evaluate relationships of rainfall/runoff, runoff pollution, sediment transport, or other physical-process aspects of stormwater planning.
MODERATELY URBAN WATERSHEDS generally contain from three to five houses per acre, with moderate to extensive drainage improvements. Impervious surfaces generally cover approximately 40 percent of the watershed.
NATURALLY VEGETATED WATERCOURSES are watercourses which support riparian plant communities dominated by natural plant species, and which may have been subject to modification or alteration in the past, but native plant species have either intentionally or naturally become re-established.
NONSTRUCTURAL ALTERNATIVES are designed to implicitly control or modify land uses, and land-use practices, in order to reduce the risk from stormwater runoff for both floodplain occupants and the community as a whole. Examples of NONSTRUCTURAL ALTERNATIVES used primarily to control the quantity of urban runoff include implementing floodplain and erosion-hazard management regulations, enforcing Zoning Regulations, flood-proofing of structures and facilities, relocation or demolition of flood-prone structures and facilities, and acquisition of flood-prone property. Examples of nonstructural alternatives used mainly for controlling the quality of urban runoff include land-use regulations; sweeping of streets and parking lots; drainage-system maintenance; storage regulation of pollution-causing materials; and slope and swale treatment for erosion control.
NPDES is an abbreviation for "National Pollutant Discharge Elimination System", which is the name of the surface water quality program authorized by Congress as a part of the 1987 Clean Water Act.
ONE-HUNDRED-YEAR (100-YEAR) FLOOD refers to a stormwater runoff event that, statistically, has a one percent chance of being equaled or exceeded in any given year. (Also commonly referred to as the REGULATORY FLOOD).
POLLUTANT LOADING means the total quantity of pollutants in stormwater runoff.
PUBLIC PARTICIPATION PROGRAM is a program designed to both inform and interact with the general public by providing educational opportunities and soliciting advisory input from a broad cross section of the interested public, as well as elected officials.
REACH is a hydraulic engineering term used to describe a section or a longitudinal segment of a WATERCOURSE.
REGULATORY FLOOD (see ONE-HUNDRED-YEAR-FLOOD).
RETENTION refers to a type of process which completely halts the downstream progress of stormwater runoff. This is normally accomplished by employing methods of total containment which generally involve the creation of storage areas that incorporate infiltration devices, such as dry wells, to dispose of stored STORM WATER via percolation over some specified period of time thereby eliminating upstream contributions to downstream stormwater runoff peaks or volumes.
RIPARIAN means relating to, or living or located on, the bank(s) of a natural WATERCOURSE.
RURAL WATERSHEDS generally contain less than one house per acre, and anticipated future drainage improvements are negligible. Impervious surfaces generally cover less than ten percent of the watershed area.
STANDARD serves as the basis for comparison to a specific achievable and measurable quantity or quality.
STORM DRAIN refers to the combination of underground conduits and surface inlet structures constructed for the purpose of removing runoff from the ground surface, usually from street pavement, and conveying it to some downstream discharge point.
STORM WATER is rainfall that accumulates in natural and/or man-made storage and STORMWATER SYSTEMS during and immediately following a storm event.
STORMWATER DIVERSION is the organized redirection of stormwater flows, either the entire flow or a portion of the flow, to another point located either within or outside of the watershed. The purpose of STORMWATER DIVERSION is to reduce flooding downstream of the diversion.
STORMWATER FACILITIES are systems such as WATERCOURSES, constructed CHANNELS, STORM DRAINS, CULVERTS, and detention/retention facilities that are utilized for the CONVEYANCE and/or storage of stormwater runoff.
STORMWATER MANAGEMENT refers to functions associated with planning, designing, constructing, maintaining, financing, and regulating the man-made facilities and natural features which collect, store, control, and/or convey STORM WATER.
STORMWATER MANAGEMENT ALTERNATIVES are specific approaches, or measures, both structural and nonstructural, for addressing the STORMWATER related needs of individual WATERSHEDS of interest.
STORMWATER MANAGEMENT PROGRAM means a long-term program which consists of policies and regulations for the planning, designing, acquiring, constructing, financing, maintaining, operating, and rehabilitation of STORMWATER SYSTEMS, both from a quantity and quality perspective. The Program will be the vehicle for the implementation of the STORMWATER MASTER PLAN.
STORMWATER MASTER PLAN is a comprehensive, system-wide, proactive plan that will address both STORMWATER quantity and STORMWATER quality needs, on a City-wide basis, by developing specific, complementary, STORMWATER MANAGEMENT ALTERNATIVES for individual WATERSHEDS being studied. A STORMWATER MASTER PLAN for the City of Tucson is being developed as Phase II of the Tucson Stormwater Management Study.
STORMWATER SYSTEM means the entire assemblage of STORMWATER FACILITIES located within a WATERSHED.
STORMWATER SYSTEM PLANNER (SSP) is a sophisticated software package that combines data management with stormwater models. A specially modified version of SSP has been utilized for TSMS to: (1) input and manage data-base files, including preprocessing information for the hydrologic model; (2) calculate system flows; (3) prepare reports and analyses; and (4) prepare graphical presentations, including interfacing with AutoCad. Modifications made to the SSP for the TSMS include the incorporation of HEC-1 as a rainfall/runoff model.
STRUCTURAL ALTERNATIVES are designed to explicitly control stormwater runoff in order to reduce the risk to both floodplain occupants and the community as a whole. STRUCTURAL ALTERNATIVES typically include major public-works projects. Generally, these types of projects require moderate to major planning and design efforts, formal approval by one or more governmental units and agencies, letting of construction contracts, moderate to large capital investments, and large operation and maintenance commitments. Examples of STRUCTURAL ALTERNATIVES used primarily to control the quantity of urban runoff include detention/retention facilities, CHANNEL modifications or enclosures, DIKES AND FLOODWALLS, and bridge and CULVERT alterations or replacements. Similarly, examples of STRUCTURAL ALTERNATIVES used mainly for controlling the quality of urban runoff include sedimentation facilities, artificial or restored WETLANDS, and infiltration systems.
STUDY AREA is the area encompassed by the corporate limits of the City of Tucson as of February 24, 1992.
SUBURBAN WATERSHEDS generally contain two houses per acre, or less, and have little or no drainage improvements. Impervious surfaces generally cover approximately 20 percent of the watershed area.
SURFACE WATER is that water which remains on the surface of the ground.
UNDERSIZED CHANNELS are defined as constructed channels which have bank-full capacities equal to or less than the 100-year peak discharge.
WASH refers primarily to a natural WATERCOURSE, usually located in an arid or a semi-arid environment, that has not been significantly disturbed by man.
WASH ORDINANCE (WASH is an acronym for "Watercourse Amenities, Safety and Habitat") is a City ordinance (see Section 29-12 of the Tucson Zoning Code, and Ordinance 7579, adopted March 25, 1991) which regulates modifications to specified WATERCOURSES located within the City of Tucson.
WATERCOURSE means a lake, river, creek, stream, WASH, arroyo, CHANNEL, stormwater CONVEYANCE system, or any other topographic feature, with well-defined banks, beds, or boundaries, on or over which stormwaters flow at least periodically.
WATERSHED is a geographical area which contributes stormwater runoff to a particular point of interest (also commonly referred to as a drainage area, a catchment, or a river basin).
XERORIPARIAN is one of the three major categories of RIPARIAN habitat. XERORIPARIAN habitats are supported by intermittent or ephemeral stream flow such as that found in desert WASHES and ARROYOS. Common plants in this habitat include, but are not limited to, mesquite, palo verde, acacia, hackberry, desert broom, and ironwood.
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