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GIS for Small Communities
Ohio Water Environment Association Collection System Specialty
Conference May 10, 2012
Christopher Heltzel, GISP
Agenda
• What is GIS
• How Does GIS Compare to CADD
• Benefits of GIS
• How to Develop a GIS
• Case Study – Harrison, OH
• Geographic
– Coordinate Projection Round Earth vs. Flat Screen
• Information System
– Database (Geodatabase)
What is GIS? Geographic Information System
GIS vs. CADD
• GIS is Data-Centric CADD is Paper-Centric
• GIS is Strong at Large Scales (mapping over kilometers and designed to address projection issues) CADD is Detail Oriented (sub-millimeter accuracy and dimensioning)
• GIS Includes Standard Connectivity/Topology Rules
Benefits of GIS
• A single seamless representation of information that can be displayed on a map
• Sharing information
– Aerial Photos
– Parcels
– Streets
– Water Bodies
– Topography
GIS for Public Utility Management
Geographic Information System (GIS)
Asset Inventory
Projects Condition
Assessment Capacity Modeling
Maintenance Management
Capital Infrastructure
Planning
Financial Management
Linear Asset Inventory
• Assets Distributed Throughout a City, County or Larger Region
• Connected Network
• Flow Tracing
• Physical Characteristics – Material
– Diameter
– Length
– Depth
Status Diameter Feet Miles
Active 6 48.32 0.01
Active 8 92,559.60 17.53
Active 10 10,087.85 1.91
Active 12 54,925.84 10.40
Active 15 28,189.26 5.34
Active 16 2,069.47 0.39
Active 18 9,226.99 1.75
Active 24 6,575.80 1.25
Active 36 7,171.11 1.36
Proposed 8 35,259.25 6.68
Proposed 12 5,475.57 1.04
Proposed 18 8,192.87 1.55
Proposed 24 8,560.26 1.62
268,342 50.82
Development of a GIS
• Identify Near-Term Needs and Long-Term Goals
• Catalog Currently Available Data Sources
• Prioritize Data Sources by Accuracy and Importance
• Create Initial GIS with Available Data, Targeting Near-Term Needs
• Perform Data Gap Analysis
• Develop Field Data Collection Program to Support Near and Long-Term Goals
Level of Accuracy
• It is better to now the approximate location of all assets than the specific location of half the assets
• A complete inventory supports a data refinement plan
• Prioritize field data collection to maximize the benefit
Case Study – Harrison, OH
• Population
– City About 10,000
– Township About 3,000
• 1.15 MGD Average / 5.36 MGD Peak Wastewater Flow
• 43.5 miles of Sanitary Sewer and Force Main ranging from 6 to 36-inches in diameter
• Sewer materials are typically vitrified clay and concrete in older sewers and PVC for sewers constructed in the last 10 years.
Wastewater Master Plan
• WW Master Plan
• SewerGEMS Collection System Model
• No Existing Model
• Existing Documentation
• CADD and Paper Sewer Atlases
• 10 Years of Plan and Profile Drawings
Import CADD Data
• Locations
• Diameters
• Flow Direction Arrows
• Some Inverts
• Missing Material
• Improperly Segmented
• Inconsistently Drawn Flow Direction
Digitize From Paper Drawings
Additional Data Processing
• Assign Manhole Rim Elevation Based on 2-foot Contours
• Assign Unique Asset ID
– “MH” Prefix
– Sequential Number
Sewer System Results
• Gravity Mains
• Pump Stations
• Force Mains
• Manholes
• Treatment Plant
• Flow Arrow
• Trace
• Basins
Results with Background Layers
• Rail Roads
• Water Bodies
• Parcels
• Streets
• Buildings
• Aerial Photography
SewerGEMS
• Export Sewer Network
– Valid Connectivity
– Pipe Diameters
– Pipe Lengths
– Pipe Inverts
• Results Can be Returned to GIS for Mapping
Maps – Existing and Future
Effort and Time
• WW Master Plan
• $50k Total
• Less than $20k for GIS Model Network
• Less than 9 Months
• GIS Software
– ArcGIS Reader (no cost)
Next Steps
Geographic Information System (GIS)
Asset Inventory
Projects Condition
Assessment Capacity Modeling
Maintenance Management
Capital Infrastructure
Planning
Financial Management
