[an error occurred while processing this directive]
[an error occurred while processing this directive]
[an error occurred while processing this directive]

DC Sewer Design Extension Manual

Martin Schaber

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is available from the Free Software Foundation (http://www.gnu.org).

CSS stylesheets referenced by this document and graphics referenced in those stylesheets are covered by a different license.

$Date: 2006-12-04 07:41:10 +0100 (Mon, 04 Dec 2006) $

Revision History
2010-03-23sdteffen
Added legal notice about CSS

Chapter 1. General

Introduction

This document describes the design process for simple sewer networks using version 2.0.10 of the DC Sewer Design extension for ArcView 3.*.

It also covers the creation of profiles (longitudinal sections) for water and sewer networks.

The DC Sewer Design Extension is free software available from http://dcwaterdesign.sourceforge.net.

You should also read the documentation of the DC Water Design Extension and the DC Processing Extension as these two extension contain related functionality. In many cases all three extensions have to be used in a combination.

What's New?

A summary of changes in different versions of the DC Sewer Design Extension.

Version 2.0.11

  • "Create Profile" allows now linebreaks in the data box titles using "+NL+"

Version 2.0.10

  • "Calculate Constant Gradient" now allows to directly specify a gradient.

  • "Create Profile" allows now to rotate text in data boxes. Configuration files need to be updated for the new format.

Version 2.0.9

  • "Create Profile" works now for line selections where the direction is not continous.

  • Bug fixes

  • Improved documentation

Version 2.0.8

Version 2.0.7

  • "Create Profile" works now for single lines.

  • It is now possible to specify the text justification for data boxes created by the "Create Profile" function.

  • Bug fixes for "Create Profile" function

Version 2.0.6

  • "Calculate Maximum Manhole Elevations" does not depend on Spatial Analyst any more.

  • New "Manhole.Legend" configuration option for profiles allows to show manholes with different symbols in the profile.

  • New "Network Calculator" function (the section called “Network Calculator”).

Version 2.0.5

  • Bug fix for profile creation (Endless loop error).

  • Improved documentation.

  • Removed the "Enforce Maxiuml Line Length" function. Please use the more powerful "Segmentize PolyLines" function of the DC Processing Extension now.

  • Added documentation on water network profiles.

  • When creating profile, the data box height for CumulativeLineData and LineData can be specified now.

  • Documentation on the creation of water network profiles.

  • New function to link designed profile back to layout.

  • Optional datum lines when creating profiles.

  • Excavation calculation example in documentation.

Requirements

ArcView version 3.* is required to use the DC Sewer Design Extension.

License

The DC Sewer Design Extension is released under the the terms of the GNU Lesser General Public License (LGPL).

Concepts

Important Concepts used in the extension.

Equations

The calculation uses the Prandtl/Colebrook Equation to calculate the Fullboard Velocity. (According to ATV Working Paper A 110) ((QT/QV)^0.305-0.0024*QT/QV)*QV is used as an approximation formula for the Free Surface Velocity. (As found in the Diagram in Schneider Bautabellen). The formulas are included in the Excel Sheet. If you are using the DBF calculation, please have a look at the source code.

Peak Factors

The Extension offers several possibilities for the peak factors: The Baumann formula: Pdom = min(2.5, 1+14/(4+SQRT(P)) ) with Pdom as the ratio of peak to average daily flow and P the population figure in thousands. Suited for cities > 80,000 population.

The Babitt formula. Suited for cities (80,000 population: Pdom = min(4.5, 5/P^(1/6)). You can also specify a constant peak factor).

How the Sewer Network is Modeled

The Extension models the Sewer Network in a very simplistic way. Therefore it has to be carefully evaluated if the calculation fulfills the given needs. All the necessary information will be kept along with a Polyline shapefile that contains the sewer network.

As sewer lines are normally straight from manhole to manhole, the extension expects that all the lines in the network have only two vertexes: One at the upstream manhole and one at the downstream manhole.

The extension expects the lines to be properly snapped: If the distance between the endpoints is bigger than 0.1m the extension will treat these lines as not connected. This means also, that all lines where the distance between the endpoints is less thant 0.1 m will be treated as connected lines.

Before you can start the calculations, the extension has to set up a simple topology: The lines have to be flipped to the flow direction. The corresponding function is included in the DC Sewer menu. The reason for this is that the calculation functions use the first vertex of a line as the upstream manhole and the second vertex as the downstream manhole.

Caution

Keep this in mind when working with the extension - you'll end up with incorrect results otherwise.

Installation

Install the extension using the setup program. Alternatively, detach the extension file (dcsewdes.avx) in the ArcView extensions folder. The extension folder is usually c:\esri\av_gis30\arcview\ext32.

You only have to do this once.

For more information on extensions, see your ArcView documentation.

Chapter 2. Reference

Usage

How to use the DC Sewer Design Extension functions.

Extension Loading

Before an extension can be used in ArcView, it needs to be loaded.

Please follow the steps below:

  1. Open an ArcView project (Unless you already have an open project).

  2. Load the Extension by choosing Extensions... from the File menu. Next, select the DC Sewer Design Extension from the list. You have to do this once for every project you want to use the DC Sewer Design Extension with.

  3. Click on the OK button.

Once the extension is loaded the functionality described below will be available.

View Menu Functions

The following functions are available from the DC Sewer in the View GUI.

Flip Lines to Flow Direction

This is the first thing you should do before you start the calculations. Just select "Flip Lines to Flow Direction" from the menu and input the Polyline theme which contains the sewer network and the field within the theme that contains the Downstream Invert Level.

The lines which have been flipped are returned as a selection from the Function. Also the Number of flipped lines is reported.

Lines flipped to the flow direction might be used for speedier Network traces.

Caution

Be sure to check to check the flow direction visually using an appropriate ArcView legend for the lines (using arrows).

Tip

It is useful to check if the Flow direction from "real" elevations is the same as the one created by "Calculate Minimum Elevation Differences": Run "Flip Lines to Flow Direction" with one field first and then with the other one - if everything is ok with your network, the script should report zero flips after the second run.

Accumulate Population

Note: This will recalculate the Accumulated Population field! You will be asked for a theme to work on and the fields "Accumulated Population" and "Population". The accumulated Population will be calculated as the sum of the population that the script finds in the population field and the summed up upstream accumulated population. The accumulated population values are set to zero on a first run over all records. Make sure that there are no network meshes in the theme. The lines have to be flipped to the flow direction before you can use this function. The Accumulated Population field can furtheron be used for the sewer calculation. It contains the population that is connected to the sewer section. At the end of the script, the accumulated population is checked against the sum of the population. The values should be equal. If not, a warning message is issued.

Optionally a field containing values for the maximum accumulated population can be specified. If this field is specified, for each line the accumulated population is reduced to this maximum value if necessary. It is possible to write out the difference between the two values to another field (optional).

Note

Specifying a maximum accumulated population field is very likely to trigger warnings about the sum of the population not matching the maximum accumulated population.

Note

Note that the accumulated population field should be a number field with at least 3 digits precision.

Accumulate Branch Length

Note: This will recalculate the Accumulated Branch Length field! You will be asked for a theme to work on and the fields "Accumulated Branch Length" and "Branch Length" For each line, the AccumulatedBranchLength will be the maxium upstream branch length plus the branch length of the line. The accumulated population values are set to zero on a first run over all records. Make sure that there are no network meshes in the theme. The lines have to be flipped to the flow direction before you can use this function.The AccumulatedBranchLength field can furtheron be used for the sewer calculation. It contains the population that is connected to the sewer section. At the end of the script, the accumulated population is checked against the sum of the population. The values should be equal. If not, a warning message is issued. This function is useful when designing vacuum sewer according to ATV A 116.

Create Dbf Sewer Calculation

To use the Menu item Create Dbf Sewer Calculation, you'll need a configuration file, that tells the extension which fields it should use. Create a plain text file on any of your drives. Use the following as a template, substitute the question marks with your field names.

    PipeID=????
    Roughness=?????
    Gradient=????
    AccumulatedPopulation=????
    Diameter=????
    PerPerson=????
    PeakFactor=????
    

The Peak Factor should either be a constant (a number), "Baumann" or "Babitt" (without ").

"PerPerson" is the sewage flow per person and day in liters.

After you select DC SewerCreate Sewer Calculation, you'll be asked for the configuration file.

Also you'll be asked for the theme that you want to run the Sewage calculation on.

If no peak factor is given, the calculation will be carried out with a constant peak factor of 1.

A confirmation dialog allows to review your configuration.

Note

To reconfigure, click on the No button in the configuration dialog.

Note

DC SewerCreate Excel Calculation will most probably not work for you due to an API change.

Calculate the Minimum Elevation Differences

Have a numerical field for the Elevations available. Set the unknown Elevations to zero. You need at least one known Elevation. ( You might set it to 1 if you want to run the Analysis without any given Elevation.) Choose "calculate Minimum Elevation differences" from the "DC Sewer" menu. You'll be asked for a Theme to run the analysis on, the Field which contains the Elevation and the minimum gradient. The analysis will trace upstream from the known elevations - all unknown elevations are considered to be upstream. The missing Elevations are calculated with the minimum gradient. Make sure that there are no network meshes in the theme.

Calculate the Maximum Manhole Elevations

Calculates the maximum manhole elevations taking the minimum cover along the section into consideration.

Requires the following themes:

  • Lines (polyline) with fields containing the information below:

    • Maximum upstream manhole elevation (number); will be overwritten

    • Maximum downsteam manhole elevation (number); be overwritten

    • Gradient (number)

    • Minimum cover (number)

  • Elevations (point) with a numeric field containing the elevation

Caution

Make sure that your lines are flipped to the flow direction. You will end up with misleading results otherwise. See the section called “Flip Lines to Flow Direction” for details.

Use the function like this:

  1. Start editing the line theme

  2. Activate the two required themes

  3. Select Calculate Maximum Manhole Elevations from the DC Sewer menu

  4. Select the fields to be used

  5. Enter the snapping radius

  6. Review and correct those values where the calculation failed (NULL values in the calculated fields)

  7. Stop editing the line theme

  8. Quality control and plausibility checks

The function will perform the following steps:

  • Loop over all lines

  • Densify the line (1m step size)

  • Select all elevation points in the snapping distance

  • Snap the point to the line

  • Calculate the maximum and minimum manhole elevations taking the point elevations, minimum cover and gradient into consideration

NULL values will be written to the maximum and minimum manhole elevation fields for those lines where no elevations could be found within snapping distance. NULL values will also be written for those lines which are not simple lines with exactly two vertices.

Tip

If your elevation source is a DTM (Digital Terrain Model), try the following:

  1. Segmentize your line theme to make it sufficiently dense. This can be done using the DC Processing Extension.

  2. Create nodes for the densified line theme. You can use the DC Water Design Extension to do so.

  3. Assign elevations from your DTM to the generated node theme. You can use the DC Processing Extension together with the Spatial Analyst to do this.

In this case, you may use a very small snapping radius.

Tip

In order to select the NULL values in the minimum manhole elevation fields, use a query statement like this:

[upmaninv].isnull

Where "[upmaninv]" is the calculated maximum upstream manhole elevation field.

Caution

Make sure that elevation points are available around your upstream manholes. In a case where the terrain is flat but an elevation is only available around the downstream manhole, the function will calculate values, but will fail to provide the minimum cover at the upstream manhole.

Enforce Drainage

Taking the results from the section called “Calculate the Maximum Manhole Elevations”, this function traces downstream and ensures that upstream sections are able to dewater to downstream sections.

Downstream sections are shifted down where necessary, retaining the gradient.

A sample configuration file for the field mappings of this function:

MaxUpstream=Upstrelev
DesUpstream=DesUpstrea
MaxDownstream=Downstrele
DesDownstream=DesDownstr
Diameter=Diameter

All elevations in m, diameter in mm.

Downstream lines will be connected in such a way that their angular point meets the angular point of the lowest upstream line when the diameter field is specified.

Validate Lines

The "Validate Lines" function from the menu checks if all the lines only contain two vertexes. Also it checks if the length is greater or equal one map unit. All invalid features are returned in the selection. The number of invalid features is reported.

Create Profile (L-Section)

The Create Profile function from the DC Sewer menu creates a longitudinal section for the lines selected in a theme.

To use the function, a line theme and a node theme sharing the proper line-node topology are required.

The user is asked for a configuration file which should contain the at least the following configuration options:

Manhole.ID=???
Manhole.Diameter=???
Manhole.InvertLevel=???
Manhole.Elevation=???
Line.ID=???
Line.Diameter=???
Line.UpstreamInvert=???
Line.DownstreamInvert=???
     

Definitions starting with "Manhole" refer to fields in the manhole table, definitions starting with "Line" refer to the line table. The "???" part has to be replaced with the actual field names of the different items.

The configuration file is a simple ASCII file that can be edited with any text editor (e.g. Notepad, Wordpad or jEdit).

In addition to the minimum configuration options, optional configuration options can be added to create more comple profiles. These options are explained below.

The created profile consists of a new shapefile and text labels.

A new view is created named "Profile UpstreamID - DownstreamID" where UpstreamID and DownstreamID are the ID of the upstream and downstream manholes, respectively.

To avoid the theme selection every time this function is called, the following configuration file options can be used:

Manhole.Theme=???
Line.Theme=???

Note

The theme names is the name as spelled in the theme properties, thus duplicate theme names in a view can cause problems.

Three different types of data boxes can be added below the profile:

  • ManholeData - One data box for each manhole

  • LineData - One data box for each line

  • CumulativeLineData - One data box stretching as long as the value doesn't change

The following is an example of the data box configuration syntax:

CumulativeLineData=diameter@1@Diameter Nominal in mm@30@Center@0

Where CumulativeLineData is the data box type, diameter is the field name in the line table, 1 is the number of decimal digits, "Diameter Nominal in mm" is the data box label, 30 is the height of the data box, "Center" is the text justification in the data box and 0 is the rotation angle.

The text justification should be one of the following:

  • Left

  • Center

  • Right

The text justification for CumulativeLineData and LineData boxes is the horizontal justification. For ManholeData boxes, it is the vertical justification.

The rotation angle should usually be one of the following:

  • 0 For horizontal text.

  • 90 For vertical text. Recommended for ManholeData boxes.

Different data boxes should be combined to obtain the desired output.

Adding the following line will add datum lines at a 5m interval:

DatumInterval=5

To display the manholes using different symbols, the following configuration option can be used:

Manhole.Legend=???

Where "???" is the placeholder for path to an ArcView legend (*.avl) that can be applied to the manhole theme.

Using this option will add an additional manhole theme to the profile view.

All manhole attributes from the layout view are copied to the profile view, allowing to create the legend file in the layout.

The field "dc_id" of the ground elevation lines will contain the dc_id of the line. This allows to link back information from the profile to the original line theme using the section called “Link Profile to Layout”

Unrecognized configuration options will simply be ignored.

Tip

This function can also be used to generate profiles for water networks.

Tip

If you would like to choose a different configuration file, after the initial selection, use the menu function Select Profile Configuration (the section called “Select Profile Configuration”).

Tip

It is possible to show upstream and downstream invert elevations for a pipe at drop manholes. If the upstream invert elevation is stored in the field "upstream" and the dowstream invert elevation in the field "downstream" of the manhole table, use the following calculator formula to fill a field that will show both elevations when used in a "ManholeData" box:

      [upstream]+NL+[downstream]

Note that the combined field with the newlines will not be displayed properly in the ArcView table.

Tip

To introduce a newline in a data box title, use "+NL+".

Caution

This function requires a field "dc_id" with unique values in the manhole and line themes. It is recommended to use this field for the "Manhole.ID" and "Line.ID" configurations.

Select Profile Configuration

Select the configuration file to be used by the section called “Create Profile (L-Section)”

Link Profile to Layout

Create a link between a profile drawn in a profile view created by the section called “Create Profile (L-Section)” and the lines in the layout.

The link is established via the "dc_id" field.

First, create an initial (ground) profile. Use the minimum cover to calculate preliminary invert levels (optional).

Add a new line theme to the profile view and design the profile (line profile). Either draw line segments between the manholes or use the Split Polylines by Polylines function from the DC Processing Extension to create the respective line segments.

Make the line profile editable.

Activate line profile and ground profile theme.

Select Link Profile to Layout from the DC Sewer menu.

The function will add the following fields to the line profile if they don't exist yet:

  • dc_id

  • upstream

  • downstream

The field dc_id will be filled for those lines where the difference (error) is less than 20% between the X values in the ground profile and the line profile.

For all lines, the fields "upstream" and "downstream" will be filled with the upstream and downstream elevations.

Note

The search radius limits the trench depth to 20m.

Use the field "dc_id" to link the lines in the profile back to the layout.

Important

The field "dc_id" has to contain unique values.

Manhole Data to Line

Transfers data from manholes to line. A source field has to be specified in the manhole table. In the line table, an upstream and a downstream field have to be specified.

Important

The lines must be flipped to the flow direction in order to use this function. See the section called “Flip Lines to Flow Direction” to see how lines can be flipped to the flow direction.

Line Data to Manholes

Transfers data from a line to the upstream and downstream. The downstream and upstream source field have to be specified in the line table together with the target field in the manhole table. Where a manhole is an upstream and downstream manhole at the same time, random decides whether the upstream or downstream value is taken over.

Important

The lines must be flipped to the flow direction in order to use this function. See the section called “Flip Lines to Flow Direction” to see how lines can be flipped to the flow direction.

View Button Functions

The following functions are available from the button bar in the View GUI.

Interpolate Constant Gradient

Interpolate a constant gradient for a series of lines matching one of the following conditions:

Upstream and downstream levels are known.
Upstream value and gradient are known.
Downstream value and gradient are known.

Example 2.1. Constant Gradient From Two Points

  1. Start editing a line theme that has three numeric fields for the upstream, downstream and gradient values.

  2. Using the table, enter a value into the upstream field for the pipe that is most upstream.

  3. Using the table, enter a value into the downstream field for the pipe that is most downstream.

  4. Select the connected sequence of pipes.

    Note

    Branches are not allowed in the selection.

  5. Click on the Calculate Constant Gradient button.

  6. When asked for the gradient, click the Cancel button.

  7. Select the upstream field from the list.

  8. Select the downstream field from the list.

  9. Review the fields, line selection and gradient.

    Click on the Yes button.


Example 2.2. Constant Gradient From Upstream

  1. Start editing a line theme that has three numeric fields for the upstream, downstream and gradient values.

  2. Using the table, enter a value into the upstream field for the pipe that is most upstream.

  3. Select the connected sequence of pipes.

    Note

    Branches are not allowed in the selection.

  4. Click on the Calculate Constant Gradient button.

  5. Enter the gradient.

  6. Click the OK button.

  7. Select the upstream field from the list.

  8. Select the downstream field from the list.

  9. Review the fields, line selection and gradient.

    Click on the Yes button.


Example 2.3. Constant Gradient From Downstream

  1. Start editing a line theme that has three numeric fields for the upstream, downstream and gradient values.

  2. Using the table, enter a value into the downstream field for the pipe that is most downstream.

  3. Select the connected sequence of pipes.

    Note

    Branches are not allowed in the selection.

  4. Click on the Calculate Constant Gradient button.

  5. Enter the gradient.

  6. Click the OK button.

  7. Select the upstream field from the list.

  8. Select the downstream field from the list.

  9. Review the fields, line selection and gradient.

    Click on the Yes button.


The function uses the digitizing direction. All lines should point into the same direction.

Note

The upstream and downstream fields only have to be selected once. To select other fields, click No in the confirmation dialog.

Table Menu Functions

The following functions are available from the DC Sewer in the Table GUI.

Network Calculator

The network calculator allows to perform calculations like the standard ArcView field calculator that also use values of upstream and downstream lines.

The network calculator extends ArcView's formulas with the following constructs:

  • Upstream.[field1]

    Where "Upstream.[field1]" will be replaced by the value of field1 for the upstream record.

  • Downstream.[field1]

    Where "Downstream.[field1]" will be replaced by the value of field1 for the downstream record.

Thus a formula like

Downstream.[invert] + [gradient]*[length]

would be converted to "333 + [gradient]*[length]" before it's passed to the standard ArcView calculator - assuming that the invert level of the downstream line is 333.

You have to choose if the calculation should start at the upstream end of the selection (downstream direction) or at the downstream end (upstream direction).

Caution

Note that "Upstream.[field]" will randomly select one of the upstream values if there is more than one upstream line.

Gravity Sewers

Building a simple gravity sewer network from scratch: Received "Routes" as Autocad Files. Cleanup, Snapping in ArcInfo, ArcView.

To purge all the Vertexes from the Polylines use "[Shape].asLine.asPolyline" with the ArcView Calculator.

Check Network Layout and Connectivity (e.g. Water Design Extension), remove all network meshes.

Manholes can be generated with "Make EPANET Model" from the DC Water Design Extension.

"Calculate Minimum Elevation Differences" could be used to create upstream/downstream topology.

"Flip lines to Flow Direction": Flow Direction could be visualized using standard arrows from ArcView.

"Calculate Flows": useful to roughly determine the required diameter, use Spatial Analysts "Assign Proximity" function or Thiessen Polygon Extension to calculate the Population for each line from population density.

Creation of DEM from contours and/or survey points.

Create 3D shapefile of pipe network with 3D Analyst and DEM.

Terrain Elevations for each line can be calculated with ArcViews Calculator: "[Shape].asList.get(0).get(0).getZ".

Calculate Terrain Gradient from the Terrain Elevations.

Design Gradient: take Terrain Gradient if suitable for expected diameter, otherwise take minimum/maximum gradient suitable for diameter - this is minimizing the excavation.

"Calculate Maximum Manhole Elevations" based on DEM and design gradient.

"Enforce Drainage" to finalize the design.

Vacuum Sewers

Simple design process for vacuum sewers according to ATV A 116.

  • Obtain population distribution, create polygon shapefile with densities.

  • Create network with DC Water Design Extension.

  • Flip lines to flow direction.

  • Segmentize Polylines function of the DC Processing Extension to enforce the maximum line length (50m).

  • Create unique manhole names.

  • Make EPANET model

  • Proximity for junctions.

  • Clip Proximity file

  • Calculate area

  • Spatial join (area -> junctions)

  • Join junctions -> lines (dc_id = node1)

  • Calculate line length

  • Calculate population

  • Accumulate population

  • Accumulate branch length

  • Calculate population density

  • Choose diameters according to table in ATV A 116

Water Network Profiles

How to generate profile drawings for the water network.

Important

Create a copy of the themes you used for hydraulic modeling as these files will be modified.

The themes must contain the following fields:

Node Theme - create this by merging the themes like reservoirs, junctions, valves, etc.

  • node (contains final junction number to be used).

  • conn_det (number - contains connection detail #)

  • diameter (number)

  • invert (number,2 decimal places)

  • elevation (number, 2 decimal places)

Line Theme

  • Material (string)

  • dn_mat (string) Combination of DN and material

  • gradient (number, 3 decimal places)

  • desupstrea (number, 2 decimal places)

  • desdownstr (number, 2 decimal places)

  • ground (string) - will contain surface material

  • prof_no (number) - will contain profile number

  • inv_down (number, 2 decimal places)

  • inv_up (number, 2 decimal places)

  • gradient (number, 3 decimal places)

Segmentize polyline theme (e.g 20m) using the / DC Processing Extension.

Load files as EPANET themes (DC Water Design Extension).

Create missing junctions (DC Water Design Extension.

Recalculate pipe length and check for very short sections (if required - mannual clean-up).

Add elevation to all points (DC Processing Extension, Spatial Analyst Extension).

Populate fields (e.g. surface "Select by Theme" or "Spatial Join")

Select profile sections and add profile number (E.g A1 scale 1:1000 < 600m)

Note

Ensure that each profile ends at a junction with permanent junction number.

Create configuration file according to requirements.

Select configuration file

Calculate temporary invert level (e.g elevation-1m)

Create profile

Rename view - use profile number

Draw water network in profile (use DC water - point and line themes).

Add x and y field to point theme and calculate x and y by ([shape].getx ?)

Calculate the elevation of points as follows using the following formula:

([Shape].getY/10) - 100

Transfer point elevation to line theme fields (inv_down; inv_up).

Calculate length of pipes and gradient ((inv_up-inv_down)/length).

Label line (gradient/length) and point (elevation=invert level) themes (Hint: use scale 1:1000 to get same label size as table)

Create the layout. The layout can include more than one view.

Water Network Profiles (Alternative)

Proposed approach for creating longitudinal sections of a water distribution network or any other pressurized system.

After the network has been designed in the horizontal dimensions (x, y) it has to be designed as well in the vertical dimension (z) which means the grades of the pipes have to be defined. After the required data has been added to the pipes in ArcView the longitudinal sections can be printed with the "Create Profile" function.

Basic Steps

  • In order to obtain the ground elevations of the project area either an accurate field survey has to be carried out or a DEM (Digital Elevation Model) has to be calculated on the basis of precise contour lines digitized from existing base maps (e.g. scale 1:50,000).

  • After a network has been designed in x-y-coordinates utilizing digital basemaps or satellite images the z-coordinates have to be defined. That means the invert level of the pipes have to be calculated considering the minimum pipe cover and the minimum grade of pipes.

  • As a first approach to obtain the most convenient grades for all pipe work a certain minimum cover has to be assumed (e.g. 1.0 m). Thus a first estimation of the invert level would be:

    Invert level = ground elevation - 1.0 m.

  • Afterwards the whole network has to be split in short pipe sections (e.g. 20 m) and the profile of each pipe has to be printed out in an appropriate scale (e.g. 1:1000 horizontal, 1:100 vertical).

  • Now the design invert levels can be determined whereby the minimum slope of 0.5 %, the minimum cover of pipes, high- and low points are representing the boundaries within the invert levels are to be chosen. For significant points like high and low points, change of gradient, section valves, air valves or washouts the invert levels will be determined manually on the print outs. Thus the gradient of the pipes will be determined as well.

Designing Invert Levels

Data fields: In the tables of the pipe.shp and the junction/node.shp the following fields are to be provided.

For pipe.shp:

dc_id String, unique ID
Groelev_up (ground elevation upstream, 3 digits)
Groelev_dw (ground elevation downstream, 3 digits)
Invert_up (invert level upstream, 3 digits)
Invert_dw (invert level downstream, 3 digits)
Length (Length in m, 3 digits)
Gradient (slope/gradient of pipe, 5 digits)
Check (optional, set to "not checked", type in "ok" after finishing the calculations for a certain sequence of pipes in order to control progress of design)

For node.shp:

dc_id String, unique ID
Groundelev (ground elevation of node)
Invert (invert level of pipe at node)

ArcView Procedures

With the "manhole data to line" function of the DC-Sewer-Design_Extension, transfer the ground elevation from the node.shp to the pipe.shp (Groelev_up, Groelev_dw).

Now use the "Calculate constant gradient" function (button in your view tool bar which shows a single line with a constant slope) as described in the section called “Interpolate Constant Gradient”. With this function the invert levels (upstream and down stream) for a selected sequence of pipes will be calculated and written into the chosen fields as well as the (constant) gradient.

Note

Select the pipes from the view and choose "Theme – Start Editing" from your menu. Then the "Calculate constant gradient" function will become active and you can run it.

Check the calculated invert levels and gradients carefully by comparing them to the levels and gradients written on your printouts.

With the "Line data to manhole" function of the DC-Sewer-Design Extension transfer the Invert_up and Invert_dw values of the pipe theme to the Invert field of the node theme.

At locations where 2 or more pipes are sharing the same downstream node, make sure that the downstream node is having the same invert level for each pipe.

Optional: Change the check field for the finalized pipes from not checked to ok.

Start drawing profiles with the "create profile" function. TIP: It is helpful in order to organise your profile-views if you add a field to your node-table called "node_no" (e.g.) in which the name of the manhole or node will be written. In your profile configuration file (config.txt) then set the Manhole.ID=node_no (first line). First you will have this node_no written in the text box of your profile plus the view which contains/shows the profile will be named with the start and end node of the related sequence of pipes instead of the dc_id.

Note

For any selected sequence of pipes the flow direction must be unique!

Open and prepare a layout with required frame and plan head and load the views with the profiles you have created into the layout.

Note

NOTE: Watch the length of the pipe sequence you have chosen. E.g. for a 1:1000 scaled map in A1 the max length of a sequences is between 550 and 600 m.

Excavation Calculation

How to calculate the necessary excavation volumes.

This example assumes that your line theme contains the following fields:

  • elevationu - The upstream ground elevation in m.

  • elevationd - The downstream ground elevation in m.

  • upstream - The upstream invert elevation in m.

  • downstream - The downstream invert elevation in m.

  • length - The line length in m.

  • trenchwidt - The trench width in m.

Use the field calculator with the following formula to calculate the excavation in cubic meters:

([elevationu]-[upstream]+[elevationd]-[downstream])*[length]*[trenchwidt]/2
      

Frequently Asked Questions (FAQ)

How to import a Digital Elevation Model (DEM) into ArcView

Assuming the DEM you want to import to ArcView is a *.dem file, in your project go to FILE - IMPORT DATA SOURCE. Choose the data type "USGS DEM". Browse for the location of your *.dem file and say "ok". Now you will be asked to browse for the location where the output grid (new folder will be established by ArcView including the grid) shall be saved. After the grid has been created you can load it to ArcView anytime with ADD THEME - DATA SOURCE = "Grid data source".

Note

Spatial Analyst is required for this procedure!

Index

G

general, General
gradient, Interpolate Constant Gradient
gravity sewer, Gravity Sewers

R

reference, Reference
requirements, Requirements

U

usage, Usage

V

vacuum network, Vacuum Sewers
validation, Validate Lines
[an error occurred while processing this directive]
[an error occurred while processing this directive] [an error occurred while processing this directive]