Smart Planning
Integrating GIS and Hydraulic Modeling to Manage Water Distribution Systems
Most New England communities have water distribution systems requiring upgrades. A key factor in sustainable operations water systems is getting the most value for the limited available funding. This is best achieved with the development of a master plan which analyzes the existing water system, develops a plan for managing infrastructure assets, and sets forth a prioritized guide for future upgrades.
Understanding and Managing Assets
A GIS system is the first step in centralizing the access to infrastructure data and locations, including water mains, hydrants, valves, curb stops, pump stations and storage tanks. Many utilities have years of paper records and mapping information stored in various locations and formats. A modern GIS system consolidates these records and organizes the information into an interactive geodatabase linked to electronic maps with central data access.
Phases of GIS Development
Implementing a GIS that incorporates multiple points of data access requires appropriate planning in order for all of the components to interconnect as one system. Phases of development include:
Building the piping network and associated attributes.
Consolidating existing water piping information.
Investigating a variety of field data including GPS field locations and data conversions from aerial imagery.
Scanning paper records and merging with electronic database formats.
Hydraulic Modeling
In developing a master plan for distribution improvements or planning for future growth, the hydraulic model is the tool that serves as a guide for analyzing, planning, budgeting, and constructing water distribution upgrades. New modeling software allows for easy integration with the GIS system, to collect the geodata from which the model is built.
A primary criteria for the design of water distribution systems relates to the provision of adequate flow rates and pressure at all locations within the system. In some cases, this may be impacted by the presence of antiquated cast iron or galvanized piping, which has lost much of its effective diameter through the accumulation of deposits on the inside of the pipe. In other cases, long-forgotten valves may be partially closed.
Other Uses of Hydraulic Modeling
The hydraulic model has numerous additional uses including:
- Emergency Response Planning and Source Tracking – ability to simulate transport of a contaminant introduced at a specific location or at a service connection.
- Water Aging Studies - ability to predict, manage or reduce water age in the
distribution system in order to reduce disinfection by-product formation.
- Computational Fluid Dynamics – ability to study mixing problems within storage tanks to reduce water age and stagnation in storage tanks.
- Source Identification and Mixing – modeling can be used to predict the origin of water at any point in a distribution system when multiple sources of supply are used.
- IDSE Studies to Comply with Stage 2 DBP Rule – hydraulic models can be used to comply with the IDSE requirements under the Stage 2 DBP Rule.
- Energy Evaluations– modeling can be used to predict energy usage in a system where water is pumped. Potential energy savings from changes in operation can also be simulated.
- Microbial Transport Studies – the source tracking tool in the modeling software can be used to predict transport of microbial contaminants in the distribution system. This innovative work can be used to determine the source of a bacteria problem in a distribution system.
Asset Management
The GIS mapping information can be fed into a formalized asset management system. A GIS-enabled asset management software allows data linkage between the two programs, such that records can be edited on either platform, and the dataset reconciled. Asset management software allows for assets to be viewed spatially in ArcGIS, while simultaneously viewing records such as asset condition, maintenance schedule, last visual inspection, etc. The software also provides capability for work order management, scheduling, and ultimately asset management maintenance system development and capital planning.
Master Plan
The end result of GIS mapping and the hydraulic modeling is the development of a master plan for the distribution system. The key feature of the master plan is the capital improvement plan (CIP) for the distribution system. The CIP provides customers, managers, operators and regulatory agencies a methodical, value based,“smart” plan for distribution upgrades. All parties have a complete understanding of what needs to be done, when it is going to be done and the associated costs. As the projects are completed, the information can be fed into the GIS, hydraulic modeland asset management systems to keep the water system in a “smart planning” mode for the future.