Flood, levee, and erosion control glossary - R
Numeric | A | B | C | D | E | F | G | H | I | J | K
L | M | N | O | P | Q | R | S | T | U | V | W | XYZ
Rainy Season
The period of the year when a specific area
receives its largest amount of rain.
Raised Beach
A wave-cut platform, with or without a covering of beach materials, which is now raised above the present sea- level.
Rapidly Varied Flow
Depth changes abruptly over a short channel
length.
Rapid Drawdown
Lowering the elevation of water against a
bank or wall faster than the structure can drain, leaving a pressure imbalance
that may cause the bank or wall to fail.
Rational Method
A means of computing storm drainage flow
rates (Q) by use of the formula Q = CIA, where C is a coefficient describing
the physical drainage area, I is the rainfall intensity and A is the area.
RCBAP
Abbreviation for Residential Condominium Building Association Policy.
RCEP
Abbreviation for rolled erosion control product.
RCRA
Abbreviation for Resource Conservation and Recovery Act,
enacted in 1976, is a Federal law of the United States contained in 42 U.S.C.
6901-6992k. It is usually pronounced as "rick-rah" or
"Wreck-rah." The Environmental Protection Agency (EPA) states that RCRA's
goals are to protect the public from harm caused by waste disposal, to
encourage reuse, reduction, and recycling, and to clean up spilled or
improperly stored wastes.
Reach
A hydraulic engineering term to describe
longitudinal segments of a stream or river. A reach will generally include the
segment of the floodplain where flood heights are primarily controlled by
man-made or natural floodplain obstructions or restrictions. In an urban area,
the segment of a stream or river between two physically identifiable points on
the stream center line would most likely be designated as a reach.
Rebar
Steel rods that are placed inside poured concrete
and become an integral part of the concrete to give it added strength.
Receiving Waters
Bodies of water or surface water systems
receiving water from upstream manmade (or natural) streams.
Recharge
The flow to ground water from the infiltration of
surface and stormwater runoff.
Recharge Area
A land area in which water reaches the zone
of saturation from surface infiltration, e.g., where rainwater soaks through
the earth to reach an aquifer.
Recharge Water
Water that seeps down from the land surface
adding to the ground water. For example, ground water is recharged from rain
water and snowmelt or from water that leaks through the bottom of some lakes
and rivers. Ground water can also be recharged when water-supply systems
(pipelines and canals) leak and when crops are irrigated with more water than
the plants can use.
Recharge Zones
The area of land that allows water to
replenish an aquifer. This process occurs naturally when rainfall filters down
through the soil or rock into an aquifer, usually in the higher gradient
section overlying the aquifer. Artificial recharge is through injection wells
or by spreading water over ground water reservoirs for any given area.
Reclaim (Water Reclamation)
Reclaim (water reclamation):
Planned use of treated effluent that would otherwise be discharged without
being put to direct use.
Recruitment
Entry of fish into a fishery either through
the attainment of a size large enough to be taken by a fishery or from an
external source (e.g., fish entering an estuary from the ocean). Recruitment
also can refer to fish reaching sexual maturity for non-exploitable species.
Recurrence Interval
The average interval in which a flood
of a given size is equaled or exceeded as an annual maximum.
Regional Detention Facility
A stormwater quantity control
structure designed to correct existing excess surface water runoff problems of
a basin or sub basin. The area downstream has been previously identified as
having existing or predicted significant and regional flooding and/or erosion
problems. This term is also used when a detention facility is used to detain
stormwater runoff from a number of different businesses, developments or areas
within a catchment. The use of regional detention facilities may be more efficient
than on-site stormwater treatment although the preferred option is to include
some on-site stormwater treatment through the use of grassy swales, etc., even
when regional detention facilities are used.
Regional Flood
A term used by the Tennessee Valley
Authority to estimate a flood comparable in magnitude to the largest known
floods on similar streams within approximately 100 miles for purposes of local
flood damage prevention planning.
Regular Program
The phase of the National Flood Insurance
Program in which communities participate once risk studies have been completed
or it is determined that detailed risk studies are not required because of low
flood risk.
Regulatory Flood Datum (RFD)
Established plane of
reference from which elevation and depth of flooding may be determined for
specific locations in the floodplain. It is the Base Flood plus a freeboard
factor of safety established for each particular area which tends to compensate
for the many unknown and incalculable factors that could contribute to greater
flood heights than that computed for a Base Flood. (See Base Flood and Freeboard definitions for clarification of cumulative definition of Regulatory
Flood Datum).
Regulatory Flood Fringe
The portion of the regulatory
floodplain beyond the limits of the regulatory floodway. The regulatory flood
fringe is subject to less frequent and lower velocity flooding and does not
play a major role in passing flood flows.
Regulatory Floodplain
The area adjoining a river, stream,
lake or ocean that is inundated by a regulatory flood. In riverine areas, the
floodplain usually consists of a regulatory floodway and regulatory flood
fringe (also referred to as a floodway fringe). In coastal areas, the
floodplain may consist of a single regulatory floodplain area or a regulatory
high hazard area and a regulatory low hazard area.
Regulatory Floodway
The area regulated by federal, state
or local requirements to provide for the discharge of the base flood so the
cumulative increase in water surface elevation is no more than a designated
amount (not to exceed one foot as set by the National Flood Insurance Program).
Rehabilitation
Implies that the land will be returned to a
form and productivity in conformity with a prior land use including a stable
ecological state that does not contribute substantially to environmental
deterioration and is consistent with surrounding aesthetic values.
Release
Any spilling, leaking, pumping, pouring, emitting,
emptying, discharging, injecting, escaping, leaching, dumping, or disposing
into the environment of a hazardous or toxic chemical or extremely hazardous
substance. Water allowed to flow from a water control structure such as a dam.
Usually the purpose of a release is to increase downstream flows or relieve
high water levels above the dam.
Release Rate
The computed peak rate of surface and stormwater
runoff for a particular design storm event and drainage area conditions.
Relocation
Moving a structure from a flood-prone area to a
new location, normally to one where there is no threat of flooding.
Repetitive Loss
A flood-caused loss of more than $1,000 to
a repetitive loss structure.
Repetitive Loss Structure
A structure for which two or
more losses of more than $1,000 (building and contents combined) have been paid
during the most recent 10-year period.
Reservoir
A man-made body of water (it is replenished by rain and river or stream
flow), which is formed after a dam is built on a river, and is used for the
collection and storage of water. In addition to providing municipal water
supplies, reservoirs provide recreational areas, are used for irrigation,
hydroelectric power, and flood control. A natural or artificially created pond,
lake or other space used for storage, regulation or control of water. May be either
permanent or temporary.
Residual Saturation
Saturation level below which fluid
drainage will not occur.
Residual Average Annual Flood Damages
Those flood damages which are not prevented by a flood control project or by other structural or nonstructural flood damage prevention measures.
Residual Flood Damages
Those flood damages which are not prevented by a flood plain management program. They may or may not be preventible by other flood control measures (including both structural and nonstructural means).
Resource Conservation and Recovery Act (RCRA)
Enacted in
1976, is a Federal law of the United States contained in 42 U.S.C. 6901-6992k.
It is usually pronounced as "rick-rah" or "Wreck-rah." The
Environmental Protection Agency (EPA) states that RCRA's goals are to protect
the public from harm caused by waste disposal, to encourage reuse, reduction,
and recycling, and to clean up spilled or improperly stored wastes.
Retention
The process of collecting and holding surface
and stormwater runoff with no surface outflow.
Restoration
The reestablishment of the structure and function of ecosystems. Ecological
restoration is the process of returning an ecosystem as closely as possible to
predisturbance conditions and functions. Implicit in this definition is that ecosystems
are naturally dynamic. It is therefore not possible to recreate a system
exactly. The restoration process reestablishes the general structure, function,
and dynamic but self-sustaining behavior of the ecosystem.
|
Photo of Restored Wetland. |
Retention/Detention Facility (R/D)
A type of drainage
facility designed either to hold water for a considerable length of time and
then release it by evaporation, plant transpiration, and/or infiltration into
the ground; or to hold surface and stormwater runoff for a short period of time
and then release it to the surface and stormwater management system.
Retrofitting
Floodproofing of existing structures.
Return Interval
A statistical term for the average time of
expected interval that an event of some kind will equal or exceed given
conditions (e.g., a stormwater flow that occurs every 2 years).
Revegetation
Reestablishing vegetative cover on ground
that has been disturbed, such as a construction site. Plants or growth that
replaces original ground cover following land disturbance.
Reverse Osmosis
Treatment that uses a very fine molecular
sieve that permits water to pass through but not contaminants. Useful for
nitrate removal.
Revetment
A facing of stone, bags, blocks, pavement, etc. either permanent or
temporary, placed along the edge of a stream to stabilize the bank, and to
protect it from the erosive action of the stream.
Revetment Surveys
EM 1110-2-1003) Surveys performed on revetments for condition and/or construction purposes.
Ridge and Runnel
Beach topography consisting of sand bars that have welded to the shore during the recovery stage after a storm. At low tide, water ponds in the runnels and flows seaward through gaps in the ridge.
Rill
A small channel eroded into the soil by surface
runoff; can be easily smoothed out or obliterated by normal tillage.
Rill Erosion
An erosion process in which numerous small channels only several inches deep
are formed. This occurs mainly on recently tilled soil or crop rows.
Rill Marks
Tiny drainage channels in a beach caused by the flow seaward of water left in the sands of the upper part of the beach after the retreat of the tide or after the dying down of storm waves.
Riparian
Located along the edge of a channel, generally on the floodplain.
Characterized by access to and influence of the channel, but not in it.
|
Photo of a Riparian. |
Riparian Buffer
An undisturbed, vegetated strip of land adjacent to a watercourse
Riparian Ecosystems
Distinct associations of soil, flora
and fauna occurring along a river, stream, or other body of water and dependent
for survival on high water tables and occasional flooding.
Riparian Habitat
Areas adjacent to rivers and streams with
a differing density, diversity, and productivity of plant and animal species
relative to nearby uplands.
Riparian Land
Land situated along the bank of a stream or
other body of water.
Riparian Vegetation
Vegetation along the bank of a watercourse.
Riparian Zone
The area of vegetation located on the bank of a natural watercourse, such as
a river, where the flows of energy, matter, and species are most closely related
to water dynamics.
|
Photo of Riparian Buffer Zone. |
Riparian/Littoral Rights
The rights of an owner of land
contiguous to a navigable body of water. If the water in question is flowing
(e.g., river or stream) the rights are said to be riparian. If the property is
subject to the ebb and flow of the tide, the rights are said to be littoral
rights. The terms "riparian" and "littoral" are commonly
used interchangeably. Riparian/littoral rights are usually defined to include -
a) the use of the water for general purposes such as swimming; and b) the right
of access to navigable waters, including the right to wharf out to
navigability.
Riper
Any implement such as a subsoiler, chisel plow, or
ripper used to break apart compacted soil layers below the normal 6 inch depth.
Riprap
Broken rock, cobbles, or boulders placed on earth surfaces, such as the face
of a dam or the bank of a stream, for protection against the scouring action of
water or waves along streams, channel banks, or shore lines caused by
floodwaters or wave action.
Riser
A vertical pipe extending from the bottom of a pond
BMP that is used to control the discharge rate from a BMP for a specified
design storm.
Risk
The probability of being flooded.
Risk Assessment
Qualitative and quantitative evaluation of
the risk posed to human health and/or the environment by the actual or
potential presence and/or use of specific pollutants.
Risk Management
The process of evaluating and selecting
alternative regulatory and non-regulatory responses to risk by considering
scientific, legal, economic, and behavioral factors.
River
A stream of water of considerable volume, which
travels downhill (from higher altitudes to lower altitudes due to gravity).
Rivers carry freshwater to cities and farms, serve as the home to wildlife and
fisheries, and provide recreation and natural beauty for people throughout the
nation. Rivers are used by humans for irrigation, to transport people and their
manufactured products, to produce hydroelectric power, and to provide habitats
for animals.
Riverine Flooding
Flooding produced by a river or stream.
|
Photo of Riverine Flooding. |
River Basin
The land area drained by a river and its
tributaries.
River Training Works
Structures placed in a stream to
direct the current into a predetermined channel.
Rock
Soil particles greater than 3 inches in diameter.
Root zone
The part or depth of the soil that is
penetrated, or can be penetrated, by crop or plant roots.
Rooted
Expression indicating that a bank has been
excavated and the end of a structure (check dam, dike, etc.) has been placed in
the cavity, thus retarding future streamflow around the end of the structure
(flanking).
Rubble
Rough, irregular fragments of broken rock or
concrete (riprap).
Runoff
The flow of water, usually from precipitation but can include other sources
(e.g., sprinkler irrigation), which is not absorbed into the ground. It flows
across the land and eventually runs to drainage facilities, rivers, streams,
springs, seeps, ponds, lakes, wetlands, shallow groundwater, stream channels,
oceans, or depressions or lowpoints in the Earth's surface. The characteristics
that affect the rate of runoff include rainfall duration and intensity as well
as the ground's slope, soil type, and ground cover. Runoff can pick up
pollutants from the air and land, carrying them into the streams, lakes, etc.
Runoff (Hydraulics)
That portion of the precipitation on a
drainage area that is discharged from the area. Types include surface runoff
and ground water runoff (seepage).
Runoff (Surface)
The flow of water across the land surface
and in stream channels. Occurs only after the local storage capacity of the
landscape has been exceeded and includes both overland flow and streamflow.
|
Photo of Runoff. |
Runup
The rush of water up a beach or structure,
associated with the breaking of a wave. Runup is measured according to the
vertical height above still water level that the rush of water reaches.
Numeric | A | B | C | D | E | F | G | H | I | J | K
L | M | N | O | P | Q | R | S | T | U | V | W | XYZ
For more information about Infrastructure Defense Technologies’ flood barriers and erosion control barriers and applications, please call us at 1-800-379-1822, email us at info@metalithH2O.com, info@infrastructure-defense.com or fill out our contact form.
Product Info | Benefits | Applications | FAQs | Resources
Flood & Erosion Control Glossary | Links | About Metalith H2O
Site Map | Contact Metalith H2O | Back to Home
The Metalith H2O
A Division of Infrastructure Defense Technologies
3575 Morreim Drive • Belvidere, Illinois 61008
Phone: 1-800-621-5617 • Fax: 1-815-323-1317
Email: info@MetalithH2O.com
Copyright ©2003-2010 Infrastructure Defense Technologies.
All rights reserved.
|
