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The HTMUA’s potable water system is represented by a GeoDatabase and contains the distribution system and service connections. Water mains are broken at a variety of fittings, including but not limited to capped ends, tees, crosses, reducers (change in diameter), changes in pipe material, and valves of all types (gate, butterfly, PRV, etc.). Mains are broken at service connections greater than or equal to 3-inch diameter. The larger services are added as lines in the same feature class as the water mains and are snapped to the lines representing water mains. Where water mains are broken, the fittings and related attributes are assigned to the point features in its respective feature class in the Geo Database.
A “service” or “lateral” is defined as a water pipe running from a pipe main directly to a building/structure with no additional branches, connections or appurtenances other than a service valve or backflow preventer. Water services are represented as lines. If the water service is 3-inches in diameter or greater – or of unknown diameter – the line is placed in the water main feature class and the associated water main line is split at the connection point with a TEE point. If the water service is less than 3-inches in diameter, the line is placed in Lateral Line feature class. The water service line is drawn from the associated main in the water system feature class to the connection point on the associated building/structure, but does not “break” the associated water main line. When valves are present on a water service, the service is split into two lines at the valve location. Valve attributes are associated with the point features in the “systemvalve” feature class.
The figure below illustrates the relationship between the water system and the water services feature class: |
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HTMUA Asset Management System Database Dictionary |
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Potable Water Distribution System |
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Fire Hydrant Representation
Fire hydrants are represented as lines. The fire hydrant line intersects and splits the water main line at the hydrant tee and a point is placed to represent the tee. The hydrant line is snapped to the hydrant cap. If the assembly includes a valve, the hydrant line is broken at the valve location and a point is placed to represent the valve attributed as HydrantValve. Each element of a hydrant assembly (lines and points) are assigned unique asset IDs. Hydrants cannot be located on or branch off from a water service line. If a line is directly connected to a hydrant that line should be coded as a distribution main only.
The following figure illustrates the proper representation of a fire hydrant with a valve: |
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Figure 1. Water System and Services features |
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Figure 2. Fire Hydrant Representation |
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Water Service Representation
A "service" is defined as a water pipe running from a pipe main directly to a building/structure with no additional branches/pipe connections and no appurtenances other than a service valve or backflow preventer.
Water services will be represented as lines. If the water service is three inches in diameter or greater – or of unknown diameter – the line will be placed in the water main feature class and will split the associated water main line at the connection point with a TEE point. If the water service is less than three inches in diameter, the line will be placed in Lateral Line feature class. The water service line will be drawn from the associated main in the water system feature class to the connection point on the associated building/structure, but will not break the associated water main line.
Hydrants cannot be located on or branch off from a water service line. If a line is directly connected to a hydrant that line should be coded as a distribution main only.
The following figure illustrates the proper representation of a Water Service: |
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Preserving Existing Identifiers
Existing potable water valve and hydrant numbers will be preserved. Where existing hydrant and valve numbers have been assigned and can be determined using existing databases, those numbers will be added to the OldHydNo and OldVaNo fields in under their respective feature class. Unique GIS facility IDs for each element of Valve and hydrant’s features will be assigned. |
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Figure 3. Water Service Representation |
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Water Tank and Pump Station Representation
Water tanks and booster pump stations, while complex in nature, are represented in the geo database as points which are connected to the distribution system and assigned a unique feature class and symbolization. Internal details (i.e., piping, pumps, footprint, valves, etc.) are not represented in the geo database.
The following figure illustrates the proper representation of a Tank: |
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Figure 4. Water Tank Representation |
