As used in this chapter, the following terms
shall have the meanings indicated:
The Board of Supervisors (BOS) of the Township of Lehigh,
Northampton County.
An underground reservoir or tank for storing rainwater.
The Northampton County Conservation District.
A pipe, conduit or similar structure including appurtenant
works which carries surface water.
An artificial barrier, together with its appurtenant works,
constructed for the purpose of impounding or storing water or another
fluid or semifluid or a refuse bank, fill or structure for highway,
railroad or other purposes which does or may impound water or another
fluid or semifluid.
The Pennsylvania Department of Environmental Protection (formerly
the Pennsylvania Department of Environmental Resources).
The magnitude of precipitation from a storm event measured
in probability of occurrence (e.g., fifty-year storm) and duration
(e.g., twenty-four-hour), and used in computing stormwater management
control systems.
A basin designed to retard stormwater runoff by temporarily
storing the runoff and releasing it at a predetermined rate.
A person, partnership, association, corporation or other entity, or any responsible person therein or agent thereof, that undertakes any regulated activity as defined in § 138-4 of this chapter.
The specific tract of land for which a regulated activity
is proposed.
A right granted by a land owner to a grantee, allowing the
use of private land for stormwater management purposes.
The documentation of the proposed stormwater management controls, if any, to be used for a given development site, the contents of which are established in § 138-18.
The removal of soil particles by the action of water, wind,
ice, or other geological agents.
The incremental depth of a stormwater management structure,
provided as a safety factor of design, above that required to control
or convey the design runoff event.
Replenishment of existing natural underground water supplies.
The area comprised of the Hokendauqua Creek Watershed and
Lehigh River Sub-Basin 3 (Dry Run and four direct drainage subareas).
See map in Appendix A[1] (provides area located within Lehigh Township only).
A surface which prevents the percolation of water into the
ground.
A structure designed to direct runoff into the ground (e.g.,
French drain, seepage pit or seepage trench).
Any natural channel or manmade conveyance system which has
the purpose of transporting runoff from the site to the mainstem.
Any stream segment or other conveyance in a Single Release
Rate, Dual Release Rate or Conditional No Detention I subarea used
as a reach in any DEP approved Act 167 study area hydrologic model.
In Conditional No Detention II subareas the main channel is the Lehigh
River.
A method for calculation of velocity of flow (e.g., feet
per second) and flow rate (e.g., cubic feet per second) in open channels
based upon channel shape, roughness, depth of flow and slope. "Open
channels" may include closed conduits so long as the flow is not under
pressure.
Lehigh Township, Northampton County, Pennsylvania.
National Pollutant Discharge Elimination System Regulations.
U.S. Department of Agriculture (formerly the Soil Conservation
Service).
The maximum rate of flow of storm runoff at a given point
and time resulting from a specified storm event.
The computer-based hydrologic modeling technique adapted
to the Watershed for the Act 167 Plan. The model has been "calibrated"
to reflect actual recorded flow values by adjusting key model input
parameters.
A method of peak runoff calculation using a standardized
runoff coefficient (rational "c"), acreage of tract and rainfall intensity
determined by return period and by the time necessary for the entire
tract to contribute runoff. The rational formula is stated as follows:
Q = CiA, where "Q" is the calculated peak flow rate in cubic feet
per second, "C" is the dimensionless runoff coefficient (see Appendix
C[2]), "i" is the rainfall intensity in inches per hour, and
"A" is the area of the tract in acres.
Any natural or man-made runoff conveyance channels used for
modeling purposes to connect subareas and transport flows downstream.
Actions or proposed actions which impact upon proper management of stormwater runoff and which are governed by this chapter as specified in § 138-4.
The percentage of the predevelopment peak rate of runoff
for a development site to which the postdevelopment peak rate of runoff
must be controlled to protect downstream areas.
The average interval in years over which an event of a given
magnitude can be expected to recur. For example, the twenty-five-year
return period rainfall or runoff event would be expected to recur
on the average once every 25 years.
That part of precipitation which flows over the land.
The former Soil Conservation Service, U.S. Department of
Agriculture, now known as the "NRCS."
An area of excavated earth filled with loose stone or similar
material and into which surface water is directed for infiltration
into the ground.
A method of runoff computation developed by NRCS which is
based upon relating soil type and land use/cover to a runoff parameter
called a "curve number."
A reservoir routing procedure based on solution of the continuity
equation (inflow minus outflow equals the change in storage for a
give time interval) and based on outflow being a unique function of
storage volume.
Areas which lack adequate stormwater collection and/or conveyance
facilities and which present a hazard to persons or property. These
areas are either documented in the applicable Act 167 stormwater management
reports or identified by the municipality or Municipal Engineer.
A system of pipes or other conduits which carries intercepted
surface runoff, street water and other wash waters, or drainage, but
excludes domestic sewage and industrial wastes.
Any plan for managing stormwater runoff adopted by Northampton
County for a watershed as required by the Act of October 4, 1978,
P.L. 864 (Act 167), and known as the "Storm Water Management Act."
[3]A watercourse.
The smallest unit of watershed breakdown for hydrologic modeling
purposes for which the runoff control criteria have been established
in the stormwater management plan.
The division or redivision of a lot, tract or parcel of land
by any means into two or more lots, tracts, parcels or other divisions
of land including changes in existing lot lines for the purpose, whether
immediate or future, of lease, transfer of ownership or building or
lot development.
A low-lying stretch of land which gathers or carries surface
water runoff.
Lehigh Township, Northampton County.
The area comprised of the Trout/Bertsch Creek Watershed and
Lehigh River Sub-Basin 1 (three unnamed creeks and direct drainage
areas). See map in Appendix B[4] (provides area located in Lehigh Township only).
Any channel of conveyance of surface water having defined
bed and banks, whether natural or artificial, with perennial or intermittent
flow.
[1]
Editor's Note: Appendix A is included at the end of this chapter.
[2]
Editor's Note: Appendix C is included at the end of this chapter.
[3]
Editor's Note: See 32 P.S. § 680.1
et seq.
[4]
Editor's Note: Appendix B is included at the end of this chapter.
