Determining wastewater contributions
and the spatial distribution of these flows throughout
the network model is a key element of sewer collection
system modeling. Models are loaded with existing
and future flows (existing and future developments),
depending on the type of analysis to be performed.
All collection sources, sewer trunks and available
wet well storage within the system are supporting
elements that provide flow routing of these system
loads. The variation of load during the course of
a day must also be accounted for during an extended
period simulation (EPS). For static analyses, total
system load for various peaking equations (e.g.,
Federov, Harman, Babbit, etc.) is spatially distributed
as a set of individual load values allocated to
selected manholes. For extended time period (EPS)
analyses, additional temporal characteristics, typically
represented by their respective diurnal variations
(hydrographs), are also required. Generally, the
sewer loading factors are first estimated for all
loading categories. The temporal effects of sewage
flows are then adjusted based on individual sewer
production categories. A spatial intersection is
then performed to geographically allocate these
generated flows to the appropriate sewer manholes,
thereby defining system loading. A load factor calculator
is then used to modify load factors to match a known
treatment plant inflow, thus completing the allocation
process. InfoSewer Load Allocator was developed
to assist wastewater engineers to greatly improve,
simplify and fully automate the process of generating
and allocating wastewater loadings for existing
system conditions and for various planning horizons.
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InfoSewer Load Allocator
An indispensable master planning tool, InfoSewer
Load Allocator offers six highly sophisticated and
fully automated flow generation methods for processing
geometric polygons to accurately compute and load
network models based on coverage type, location,
and variation. These methods are:
- Geocoded meter billing data (meter consumption
database)
- Polygon Intersection – spatial intersection
of multiple polygon layers
- Polygon Extraction – spatial summation
of load category area polygons
- Closest (Nearest) Manhole Method
- Closest (Nearest) Pipe Method
- Individual Point Loadings
The first method makes use of GIS layers to automatically
geocode sewer loadings. The wastewater load at
each manhole is determined by identifying and
summing all the flow data within its associated
sanitary service area polygon. In the second method,
sewer loadings are automatically calculated based
upon a direct spatial intersection between wastewater
load categorization polygons (e.g., land use and
population polygons) and the sanitary service
area polygons (also know as sewersheds or service
basins). In the third method, manhole loadings
are generated by summing the individually assigned
load category polygons. Both fourth and fifth
methods work in conjunction with geocoded billing/meter
data. The fourth method locates the manhole closest
to each billing meter by using efficient search
algorithms and then allocates manhole loadings.
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In the fifth method, search algorithms are used
to locate the closest sewer pipe to each geocoded
meter location. Loads are then assigned to the nearest
manhole on either side of the pipe or divided based
on a distance-weighted approach.
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The last method allows you to simply inject flows
you have calculated yourself directly as point loads.
Within a true GIS environment, InfoSewer Load Allocator
also allows you to create, edit, manipulate, and
manage all your GIS polygons and their associated
data with incredible ease and astounding speed.
These comprehensive capabilities will let you effectively
utilize your engineering knowledge and experience
and leverage your existing GIS data investments
to strategically define/forecast your sanitary sewer
network flows for various planning horizons in your
master planning effort.
Automated Service Area/Boundary
Polygons
A complete GIS application software, InfoSewer Load
Allocator Pro also allows you to automatically create,
edit, manipulate, move, and manage all your GIS
polygons and their associated data with incredible
ease and speed. A very powerful and efficient Thiessen
polygon generation capability is provided that lets
you automatically create a distinct service area
polygon (contributing area) for any or all manholes.
Thiessen polygons provide a means to divide an area
into polygons by creating regions that bisect known
points. These polygons typically signify the bounded
region closest to each of the manholes.
Considerable flexibility (four useful and practical
methods) is also provided for defining the boundary
of the Thiessen polygons to ensure accurate representation
of the sewer loads generated throughout the collection
system.
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Application Dependent
- InfoSewer Suite. |
