In the field of wastewater infrastructure design, the initial and arguably most critical step in the data collection process is the systematic mapping of the area to be surveyed. As outlined in the competency standard “Design Wastewater Collection and Treatment Infrastructure” (Unit Code: CON/OS/CET/CR/09/6A), area to be surveyed is mapped out based on job requirements/specifications—a principle that ensures the survey scope aligns precisely with project needs, regulatory standards, and client expectations.
This comprehensive guide explores how area to be surveyed is mapped out based on job requirements/specifications, examining the key steps, methodologies, tools, and best practices that underpin effective wastewater site surveys. Proper site mapping serves as the foundation for subsequent analysis, design, and construction activities, ultimately determining the success of the entire wastewater infrastructure project.
1. Understanding the Survey Requirements
1.1 Defining the Project Scope
The first step in mapping the survey area is a thorough review of the job requirements and specifications. As highlighted by industry professionals, “It is not too difficult to specify the total road length, method of survey (TS, DGPS, Drone with LIDAR), grids of the survey and the specific outputs expected from the survey” . However, incomplete or vague specifications remain a common challenge, with some bid documents merely asking bidders to conduct “necessary” surveys without providing adequate detail .
When area to be surveyed is mapped out based on job requirements/specifications, the following elements must be clearly defined:
1.2 Regulatory and Contractual Requirements
The mapping process must comply with applicable regulations and contract terms:
Professional Licensing Requirements:
Regulations often require that licensed professionals perform specific survey tasks. For example, locating boundaries and physical features on maps may be considered “practicing surveying” requiring a Professional Land Surveyor .
Specific Mapping Requirements for Wastewater Systems:
When area to be surveyed is mapped out based on job requirements/specifications, the following must typically be included:
- Horizontal and vertical position, including accuracy levels
- Cross-sectional size
- Material type (e.g., PVC, concrete, ductile iron)
- Maintenance holes and chambers
- Catch basins
- Inlet and outfall structures
- Pumping stations and wet wells
- Abandoned utility infrastructure
2. Preliminary Data Collection and Research
2.1 Gathering Existing Information
Before conducting field surveys, engineers must collect and review existing data sources. When area to be surveyed is mapped out based on job requirements/specifications, this preliminary research includes:
2.2 Stakeholder Consultation
Effective mapping requires engagement with relevant stakeholders to understand their specific information needs:
Key Stakeholders to Consult:
- Local authorities and municipal departments
- Department responsible for operation and maintenance
- Project employer and client representatives
- Regulatory agencies
- Community representatives
Questions to Address During Consultation:
- What is the expected design period? (typically 20 years)
- What growth projections exist for the service area?
- What are the required setbacks for wastewater facilities?
- What existing data is available from the responsible department?
3. Site Evaluation and Characterization
3.1 Site Plan Development
When area to be surveyed is mapped out based on job requirements/specifications, a site plan is essential for documenting the area to be surveyed. Comprehensive site surveys capture :
Site Details to Record:
- Customer and site details
- Access constraints and ground conditions
- Drainage field sizing and meterage
- Percolation test results and soil types
- Existing utilities and service plans
- Inlet and outlet drainage measurements
- Power supply and cabling requirements
- Excavation scope and reinstatement needs
Regulatory Documentation:
- EA permit requirements
- Building notice requirements
- Section 50 approvals
- Maintenance requirements
- Planned and emergency procedures
3.2 Location and Topography
For wastewater infrastructure, location and topographic information must be carefully documented. When area to be surveyed is mapped out based on job requirements/specifications, the following elements are essential :
| Element | Source | Use in Design |
|---|---|---|
| Latitude/Longitude | Survey of India maps 1:25000/1:50000 | Project location |
| Distance from important cities | District planning maps, Google | Access planning |
| Height above MSL | Survey of India maps | WSP and STP design |
| Contours | Topographic maps, site survey | STP location, zoning, drainage |
| Physical features (rivers, drains, hills) | Survey of India maps | Site constraints, outfall locations |
3.3 Environmental Mapping
Wastewater infrastructure mapping must identify environmental resources and constraints :
Environmental Features to Map:
- Ephemeral, intermittent, and perennial streams
- Springs and groundwater discharge features
- Lakes, ponds, and other surface water bodies
- Wetlands and floodplains
- Existing and abandoned wells
Setback Requirements:
A 500-foot (approximately 152m) review boundary is commonly required for:
- Wells (including usage and construction details)
- Streams and surface drainage features
- Springs and lakes
- Property boundaries
3.4 Soils and Geotechnical Assessment
Soil investigation is critical for wastewater infrastructure design. When area to be surveyed is mapped out based on job requirements/specifications, a comprehensive soils evaluation is required :
Soil Evaluation Requirements:
- Confirmation of county soils map
- Field description of soil profile through excavation pits or auger borings (to 7 feet or to bedrock)
- Description of diagnostic horizons
- Identification of restrictive horizons
- Assessment of seasonal high water table
Key Soil Parameters to Document:
- Thickness of each horizon
- Texture and color
- Structure and internal drainage
- Depth and type of restrictive horizons
- Evidence of seasonal high water table
3.5 Hydrogeological Assessment
For land application systems, hydrogeological conditions must be characterized :
Hydrogeological Mapping Elements:
- Regional and local geology
- Depth to groundwater and groundwater movement
- Hydraulic conductivity and transmissivity of affected aquifer
- Relationship between affected aquifers and local/regional hydrogeology
- Groundwater flow regime prior to and during operations
Groundwater Quality Baseline:
4. Survey Methodology and Tools
4.1 Survey Methods
When area to be surveyed is mapped out based on job requirements/specifications, the appropriate survey methods must be selected:
4.2 Required Survey Information
When area to be surveyed is mapped out based on job requirements/specifications, the following information is typically required :
Horizontal and Vertical Position:
Feature Attributes:
- Feature dimension and type
- Feature type abbreviation
- Material type
- Accuracy level for each feature
- Spatial X, Y, Z coordinates
Color Coding for Utility Mapping :
| Colour | System Type | Application |
|---|---|---|
| Green | Wastewater systems | Sanitary sewer, storm drains, combined systems |
| Blue | Water systems | Potable and non-potable water mains |
| Red | Electrical systems | Power lines, cables, conduit |
| Orange | Telecom systems | Communication, signal lines |
| Yellow | Liquid and petroleum gas systems | Gas, oil, steam |
| Purple | Greywater | Reclaimed water, irrigation, slurry lines |
5. Mapping Outputs and Deliverables
5.1 Key Mapping Deliverables
When area to be surveyed is mapped out based on job requirements/specifications, the following deliverables are typically produced:
5.2 Integration with Design Process
The survey outputs directly inform subsequent design activities :
- Topography → STP location selection and zoning
- Height above MSL → WSP design parameters
- Flow direction in drains → Sewer zone boundary definition
- Drain and sewer connection points → Elimination of mixing points
6. Conclusion
The systematic mapping of the area to be surveyed based on job requirements and specifications is a foundational step in wastewater infrastructure design. From defining the project scope to selecting appropriate survey methods, documenting site conditions, and producing comprehensive deliverables, every aspect of the mapping process must align with the specific requirements of the project.
Key takeaways for engineering practice:
- Define requirements clearly—complete specifications are essential for effective surveying
- Collect existing data first—review available maps and records before field surveys
- Comply with regulations—ensure licensed professionals perform required tasks
- Document comprehensively—record site details, access constraints, soils, and utilities
- Produce GIS-compatible deliverables—integrate survey outputs with design systems
By following a systematic approach to mapping the survey area, engineers can collect the critical data needed to design wastewater infrastructure that is safe, compliant, and sustainable.