Interpretation of Terms or Words
Regardless of capitalization, definitions are standard for the intent of these Design Criteria.
AASHTO
American Association of State Highway and Transportation Officials
ANSI
American National Standard Institute
APHA
American Public Health Association
ASCE
American Society of Civil Engineers
ASTM
American Society for Testing and Materials
AVERAGE DAILY FLOW
The total quantity of liquid tributary to a point divided by the number of days of flow measurement.
AWWA
American Water Works Association
BEDDING
The earth or other materials on which a pipe or conduit is supported.
CATCH BASIN
A structure intended to collect surface runoff and direct it into the storm sewer system.
COLLECTOR SEWER
A sewer normally less than 15 inches in diameter that receives wastewater from the sanitary laterals and transports it to the interceptor sewer.
CORPORATION STOP
The fixture tapped into a water main to connect a service to the main.
CRITICAL DEPTH
The depth at which point the control for determining the headwater for culverts changes.
CROSS-CONNECTION
(a) A physical connection through which a supply of potable water could be contaminated or polluted.
(b) A connection between a supervised potable water supply and an unsupervised supply of unknown potability.
CULVERT
A structure which allows surface runoff to flow through a roadway fill or similar obstruction of open flow. Culverts may be corrugated metal pipe, reinforced concrete, etc.
CURB INLET
A specialized catch basin (see catch basin) designed to collect runoff from pavement with curbing.
DESIGN STORM
The expected frequency of the storm for which the capacity of a structure will be equaled or exceeded. The capacity of a storm sewer designed for a 10-year storm has a 1 in 10 chance of being equaled or exceeded in any given year.
DETENTION/RETENTION
The term detention/retention basin refers to the use of a storm water storage facility which will store storm water and release it at a given rate. The objective of a detention/retention facility is to regulate the rate of runoff and control the peak discharges to reduce the impact on the downstream drainage system.
Type of Storm Water Storage Facilities:
(a) Detention Basin or Dry Basin - Dry basins are surface storage areas created by constructing a typical excavated or embankment basin.
(b) Retention Basins or Ponds - Retention basins are permanent ponds where additional storage capacity is provided above the normal water level.
(c) Parking Lot Storage - Parking lot storage is a surface storage facility where an inlet is undersized causing shallow ponding to occur in specific graded areas of the parking lot.
(d) Subsurface Storage - Subsurface storage is a structure constructed below grade for the specific purpose of detaining storm water runoff.
DISCHARGE
The amount of flow carried by a sanitary sewer, culvert, or storm sewer, normally measured in cubic feet per second.
DRAINAGE AREA
The area, in acres, which drains to a particular catch basin, culvert, or similar structure.
DROP MANHOLE
A manhole installed in a sewer where the elevation of the incoming sewer considerably exceeds that of the outgoing sewer; a vertical waterway outside the manhole is provided to divert the wastewater from the upper to the lower level so that it does not fall freely into the manhole except at peak rate of flow.
EARTH-DISTURBING ACTIVITY
Any grading, excavating, filling, or other alteration of the earth’s surface where natural or manmade ground cover is destroyed and which may result in or contribute to erosion and sediment pollution.
ENERGY GRADIENT
The slope of the energy line of a body of flowing water with reference to a datum plane.
ENERGY GRADIENT LINE
The line representing the gradient which joins the elevation of the energy head.
ENERGY HEAD
The height of the hydraulic grade line above the centerline of a conduit plus the velocity head of the mean velocity of the water in that section.
ENERGY LINE
A line joining the elevation of the energy heads; a line drawn above the hydraulic grade line by a distance equivalent to the velocity head of the flowing water at each section along a stream, channel, or conduit.
EROSION
(a) The wearing away of the land surface by running water, wind, ice, or other geological agents, including such processes as gravitational creep.
(b) Detachment and movement of soil or rock fragments by wind, water, ice, or gravity.
(c) Erosion includes:
(1) Accelerated erosion: Erosion much more rapid than normal, natural or geologic erosion, primarily as a result of the influence of the activities of man.
(2) Floodplain erosion: Abrading and wearing away of the nearly level land situated on either side of a channel due to overflow flooding.
(3) Gully erosion: The erosion process whereby water accumulates in narrow channels during and immediately after rainfall or snow or ice melt and actively removes the soil from this narrow area to considerable depths such that the channel would not be obliterated by normal smoothing or tillage operations.
(4) Natural erosion (geological erosion): Wearing away of the earth’s surface by water, ice, or other natural environmental conditions of climate, vegetation, etc., undisturbed by man.
(5) Normal erosion: The gradual erosion of land used by man which does not greatly exceed natural erosion.
(6) Rill erosion: An erosion process in which numerous small channels only several inches deep are formed; occurs mainly on recently disturbed soils.
(7) Sheet erosion: The removal of a fairly uniform layer of soil from the land surface by wind or runoff water.
EXFILTRATION
The quantity of wastewater which leaks to the surrounding ground through unintentional openings in a sewer. Also, the process whereby this leaking occurs.
FIRE HYDRANT
A fixture installed throughout urban water distribution systems to provide water for the fire fighting needs.
GRASSED WATERWAY
A broad or shallow natural course or constructed channel covered with erosion-resistant grasses or similar vegetative cover and used to conduct surface water.
HEADWALL
A structure placed at the ends of a culvert to prevent movement of the culvert and reduce erosion.
HEADWATER
The vertical distance from a culvert invert at the entrance to the water surface upstream from the culvert.
HOUSE CONNECTION
The pipe carrying the wastewater from the building to a common sewer. Also called building sewer, house sewer, or sanitary lateral. The house connection begins at the outer face of the building wall.
HOUSE SEWER
A pipe conveying wastewater from a single building to a common sewer or point of immediate disposal. (See House Connection)
INFILTRATION
The discharge of ground waters into sewers, through defects in pipe lines, joints, manholes, or other sewer structures.
INFILTRATION/INFLOW
A combination of inflow wastewater volumes in sewer lines with no way to distinguish either of the two basic sources, and with the same effect as surcharging capacities of sewer systems and other sewer system facilities.
INFLOW
The discharge of any kind of water into sewer lines from such sources as roof leaders, cellars, sump pumps and yard-area drains, foundation drains, commercial and industrial so- called “clean water” discharges, drains from springs and swampy areas, etc. It does not “infiltrate” into the system and is distinguished from such wastewater discharge, as previously defined.
INLET CONTROL
A situation where the discharge capacity of a culvert is controlled at the culvert entrance by the depth of headwater and the entrance geometry, including the area, shape, and type of inlet edge.
INTERCEPTOR SEWER
A sewer which receives the flow from collector sewers and conveys the wastewater to treatment facilities.
JOINTS
The means of connecting sectional lengths of sewer pipe into a continuous sewer line using various types of jointing materials with various types of pipe formations that make possible the jointing of the sections of the pipe into a continuous collecting sewer line. The number of joints depends on the lengths of the pipe sections used in the specific sewer construction work.
JURISDICTION
Any governmental entity, such as town, City, county, sewer district, sanitary district or authority, or other multi-community agency which is responsible for and operates sewer systems, pumping facilities, regulator-overflow structures, and wastewater treatment works.
MAIN
The large water-carrying pipe to which individual user services are connected. Mains are normally connected to each other in a grid-type system.
MAIN SEWER
In larger systems, the principal sewer to which branch sewers and submains are tributary, are also called trunk sewer. In small systems, a sewer to which one or more branch sewers are tributary.
MANHOLE
An opening in a sewer provided for the purpose of permitting a man to enter or have access to the sewer.
MANNING ROUGHNESS COEFFICIENT
The roughness coefficient in the Manning Formula for determination of the discharge coefficient in the Chezy Formula.
METER
The flow-measuring device installed at each service on a distribution system to measure the amount of water consumed by users at that service.
NSF
National Sanitation Foundation
NORMAL DEPTH
The depth at which water will flow in a pipe or channel by virtue of its slope and roughness, based on the Manning formula.
OEPA
Ohio Environmental Protection Agency
OUTLET CONTROL
A situation where the discharge capacity of a culvert is controlled by the barrel of the culvert, rather than the inlet.
OVERFLOW
A pipe line or conduit device, together with an outlet pipe, which provides for the discharge of a portion of sewer flow into receiving water or other points of disposal.
PEAK
The maximum quantity that occurs over a relatively short period of time. Also called peak demand, peak load.
RAINFALL INTENSITY
The amount of rain falling over a specified period of time. Rainfall intensity is usually measured in inches per hour.
RATIONAL FORMULA
The method used to determine the amount of runoff from a specified area of known surface characteristics.
RUNOFF COEFFICIENT
A coefficient used in the Rational Formula to express the ratio of runoff to rainfall.
SANITARY SEWER LATERAL
The sewer line extending from the public sewer to the nearest property line of the property to be served.
SANITARY WASTEWATER
(a) Domestic wastewater with storm and surface water excluded.
(b) Wastewater discharging from the sanitary conveniences of dwellings (including apartment houses and hotels), office buildings, industrial plants, or institutions.
(c) The water supply of a community after it has been used and discharged into a sewer.
(d) See Ordinance 72-19 dated November 20, 1972 for further explanation.
SEDIMENT
Solid material both mineral and organic, that is in suspension, is being transported, or has been moved from its site of origin by wind, water, gravity, or ice, and has come to rest on the earth’s surface above or below sea level.
SEDIMENT BASIN
Barrier, dam, or other suitable detention facility built across an area of waterflow to settle and retain sediment carried by the runoff waters.
SEDIMENT CONTROL PLAN
A written description, acceptable to the approving agency, of methods for controlling sediment pollution from accelerated erosion on a development area of 5 or more contiguous acres or from erosion caused by accelerated runoff from a development area of 5 or more contiguous acres.
SEDIMENT POLLUTION
Failure to use management or conservation practices to abate wind or water erosion of the soil or to abate the degradation of the waters of the state by soil sediment in conjunction with land grading, excavating, filling, or other soil-disturbing activities on land used or being developed for commercial, industrial, residential, or other purposes.
SERVICE
The pipe carrying water to individual houses or other users on a distribution system.
TAILWATER
The vertical distance from a culvert invert at the outlet to the water surface downstream from the culvert.
TIME OF CONCENTRATION
The time for water to reach a certain point in the drainage area. In the case of gutter flow, the time of concentration includes the time to the gutter and the time of flow in the gutter to a specified point.
(Ord. 4206. Passed 1-24-06.)