2. Sewer/Storm Mapping Project
Phase Two Regulations
The current status of the sewer mapping project, as of August 2005, is that the
majority of the town’s sewer lines and storm mains have been mapped so long as the
maps have been scanned. The major subdivisions have been added and the major
extension projects have been added so long as the maps were scanned.
The current sewer print out has been handed to Sewer Department to check and
add scan numbers. The next big portion of the project is to collect the field data and a
process for doing that, is still under consideration.
A problem has arisen and needs to be considered for the completion of this
project. The problem is that some of the small storm/sewer projects have been marked
with the GPS unit and could be placed into the sewer network in Arc Map. The problem
is that the current way that the maps are added is by stretching them to fit the current
parcel layer. In short, the problem with mixing GPS located marks and scanned marks is
that they could be off by as much as 20 feet. Now from an office view that may
excellent, but from the field stand point, that margin of error is worse than guessing.
To have a proper system mapped with all the needed data that could be utilized
for the purposed uses, the town really needs to look into having the whole system GPSed.
Obviously to GPS the whole system would take a lot more time and a lot more money but
the end product would be a system that a minimal margin of error, actual size grates, and
accurate invert data. Not only would the system benefit from this style of mapping but
also it would give the town a chance to inspect each structure and comment on what
repairs may be needed and what if any miss connections between storm and sanitary may
exist.
Other benefits to the town from this system is that when it is complete it can be
used to locate man holes in the winter, help support the local fire department during any
hazardous material spill, and the need for inspections and maintenance of the current
system.
Although this style will cause headaches and appears as if we are starting over
again, which we really are. The end system will be much better and serve the public
much more efficiently and accurately then the current mapping style.
Procedure to input map scans:
1. Place a copy of the scanned map in:
G:OriginalGISData(restricted)Engineeringsewerscans
2. To place the scan into the Arc Map go to the tool box (Red Box icon), from there
open the copy raster command, find the correct number scan from the right folder and
start the raster process.
3. Once the map is in the system find an anchor point on the map and click on the
georeferencing tab: click the add control point icon, then click your anchor point one the
scan first then find the same point on the main map.
3. 4. Repeat this at least once more for a total of two control points. Make sure your
control points are close to the data point you will be entering.
5. Start editing and enter each data point, making sure you have the correct main
size, type of manhole, or size of catch basin.
6. Save often.
Summer Intern 2005
Kenneth Meding
4. Procedure for Elevation Data Recording of System Structures
The Elevation Data for System Structures is the next step for the completion of the Phase
Two Regulations for Strom and Sanitary Mapping. The data that needs to be recorded is
listed out in the following procedure.
Step One: Data Sheet
Use the correct data sheets located in the back of the Data Collection Field Book.
Fill out the current data on the sheet in regards to the date and weather conditions.
Step Two: Location of Structure
The location of the structure can be determined by using the Quad Sheets for that
type of system. The first sheet in the Quad Sheets section of the Data Collection Field
Book is an overview of all of the Quad sheets for the town. Use this sheet to get a idea of
which Quad the structure might be in. Using the more detailed 16 Square Sheets that
follow the overview sheet, find the exact Quad name for that structure. Use land marks
on the map like road intersections, road bends, and counting structures back from a
known location, to help ensure that right Quad name is used.
Step Three: Naming of the Structure
The procedure for naming structures is in the Data Collection Field Book and
should be followed to name any structure. Along with naming the structure also find the
watershed or main sewer district that the structure lies in. Record that data on the sheet.
Step Four: Rim Conditions
As the structure is being named and the data sheet is being filled out, use the GPS
unit to find the elevation of the rim. This measurement is vital to all other data necessary
to complete of the Phase Two Regulations. Also determine the size of the rim and the
type of the rim, whether it is an open or closed structure. Record that data on the sheet.
Step Five: Inspection of Conditions
Remove the cover (If covered) of the structure and inspect the conditions of the
coating, the bench, the steps, and record any data and comments that are necessary on the
data sheet.
Step Five: Elevations and Diameters
The elevations and diameters of the laterals in any structure can be measured
without the need to get into the structure. Use the following steps to gather the necessary
data.
USE THESE STEPS IF ELEVATION MEASURMENT IS DIFFCULT
Step ABLE
Using a compass find the directions of each lateral
Step BAKER
5. Using the Elevation/Diameter Tool with the Elevation Tip on the
end, measure IN INCHES the distance from the inside of the rim to about the center of
the lateral. This distance is the hypontuse of a triangle(H-Value).
Step CHARILE
Using a tape measure, measure IN INCHES the distance from the
inside of the rim, the same spot used to step BETA, to center of the lateral on the top
of the structure. This distance is the horizontal distance between the two(X-Value).
Step DOG
With two sides of the triangle known use the Elevation Sheets in
the Data Collection Field Book (The H-Values are on the right and left sides, the X-
Values are on the Top and Bottom, and the Y-Values are in the chart) to find the vertical
distance between the rim and lateral. When you know the true vertical distance from the
rim to the center of the lateral then subtract that vertical distance from the elevation of the
rim. This will give the true elevation of the lateral. Remember to convert back to feet.
Step EASY
Using the Elevation/Diameter Tool with the Diameter Tip on the
end, measure the diameter of each lateral and record the values.
Step FOX
Repeat all steps for each lateral and record data.
USE ACCOMPING DRAWINGS AND EXAMPLES FOR HELP IF NECESSARY
Step Six: Pictures
If requested take pictures if possible for inspection purposes. Record picture
number and roll number on the data sheet.
Step Seven: Conclusion
Add any comments necessary and return cover to structure.
6. Classification Procedure for System Structure
The naming of structures for the phase two regulations of Strom and Sanitary systems
will consist of five parts. An example is below and each part is explained in full.
System – Type of structure – Quad – Year of installation – Number within quad
Example:
ST - MH - B26 - 2005 – 3
System: The system part referrers to which one of the two systems the structure belongs
to. The only options are Sanitary (SA) or Storm (ST).
Type of structure: Types of structures to be inspected and named are: Man Holes (MH),
Catch Basins (CB), Inlets (IL), Outlets (OL), Clean Outs (CO), and Outfalls (OF).
Other consideration needs to be taken into account as to whether the structure is open or
closed. This should portrait to the storm structures only. If a storm structure is open to
then the part with the Type of structure will be followed with an (O). Example below:
ST - MHO - B26 - 2005 – 3
Catch Basins are to be considered to be open already and do not need to have the extra
notation.
Quad: In the Sanitary/Storm Mapping Data Collection Field Book there are quad maps
made from the Arc View mapping of the two systems. These maps are not complete and
not up to date, but the Quad location names will not change and will work well for the
Quad part of the classification of structures. The use of the Quad name should be done in
an alphanumeric fashion. The letter should be first and followed by the number. If a
structure falls onto the Quad lines on the map pages then the best guess by the inspector
is to be taken and used. To indicate that a guess had to be made follow the Quad part
with an (*). Example below:
ST - MHO - B26* – 2005 – 3
Year of installation: If the year of installation is known then it should be used for this
part. If the year is not known then the current year that the inspection is taking place will
be used and followed by and (*) to indicate that the year of installation is not currently
known. Example below:
ST - MHO - B26* – 2005* – 3
Number within quad: The number within the quad that a structure lies will be counted
from the upper most left corner first and ending the bottom most right corner. If a
structure falls onto the Quad lines on the map pages then the best guess by the inspector
7. is to be taken and used. To indicate that a guess had to be made follow the Number
within quad part with an (*). Example below:
ST - MHO - B26* – 2005* – 3*
Elevation/Diameter Tool
The Elevation/Diameter Tool is a simple tool made form EMT that has inches
measures out on the length of the tool. These inch marks will be used to determine the
distance to find the true elevation of a lateral without having to enter a manhole.
The tool needs to have one end with threads to allow the addition of other tips to
increase the accuracy of measurements.
The Elevation Tip is nothing more then a blunt end to the EMT. The tip could be
paint a bright color so that is can be seen within the manhole.
The Diameter Tip is nothing more then a ruler added to the end of the EMT to
determine the diameter of laterals. The T-section of the tip needs to have inches marked
out on it for measurements.
