?? Role of a Design Engineer as a Team Member in Infrastructure Design Projects ??

This article provides an overview of a design engineer’s structured and methodical approach to Infrastructure projects.

As a key member of the Design Team, our role in planning and designing Wet Utilities for a new city—whether planned or unplanned—follows a structured and methodical approach. Each step ensures that the infrastructure is efficiently designed and ready for implementation.

1?? Setting Objectives and Project Scope

First of all, we establish the project’s objective and scope. The formal process begins with:

• Inception Report: Analyzing project feasibility and requirements.
• Preliminary Design Report: Early-stage planning and conceptual designs.
• Detailed Design: Addressing all technical details to finalize the design.

Source Identification for Water Supply

Determining the optimal water source, whether groundwater or surface water, requires a thorough evaluation of multiple factors:

I) Groundwater Assessment:

• Conduct an Electric Resistivity Survey (ERS) to assess the availability, quality, and sustainability of underground water.
• Evaluate the groundwater recharge rates and potential for long-term supply.

II) Surface Water Analysis:

• Identify the proximity and accessibility of surface water sources.
• Analyze the feasibility of constructing a transmission mainline for water delivery, factoring in:
• Length of the pipeline (longer lines increase costs).
• Hydraulic losses (head losses due to friction).
• Water hammer analysis to ensure the safety and durability of the pipeline under pressure fluctuations.

III) Cost and Community Needs:

• Compare operational and maintenance costs for surface water treatment plants versus groundwater extraction and treatment.
• Ensure the selected source can meet the community's water quality and quantity requirements.

Ultimately, a detailed technical and financial analysis guides the selection of the most viable and sustainable water source for the community.

Location of Sewerage Treatment Plant (STP)

The placement of a Sewerage Treatment Plant (STP) is a critical decision in infrastructure planning and depends on several key factors:

I) Topography and Road Gradient:

• The STP is typically located at the lowest point of the project area to allow gravity-based flow of wastewater, minimizing the need for pumping stations and reducing operational costs.

II) Flow Direction and Watershed Analysis:

• Proper watershed analysis is conducted to ensure the natural flow of wastewater aligns with the planned location of the STP. This ensures efficient collection and avoids unnecessary diversions.

III) Land Availability:

• Adequate land should be available at the selected site, considering future expansion and compliance with environmental regulations.

By strategically placing the STP based on these considerations, the design ensures efficient wastewater management while optimizing costs and environmental sustainability.

2??Site Visit: Understanding the Project Area

The process begins with a site visit to assess the existing conditions of the project area. This critical step helps identify key considerations and challenges.

What to focus on during a site visit?

?? Key Considerations for Site Visits as an Infrastructure Design Engineer(Existing developed city or planning a new city)Site visits are critical in wet utility design, whether you're working in an existing developed city or planning for a new city. Here's what to focus on during your site inspections:

For Existing Developed Cities

I) Right-of-Way (RoW): Check if the road's right-of-way is available for proposed water, sewer, or storm utilities.

II ) Existing Utilities: Identify the dry (e.g., electrical, telecom) and wet (e.g., water, sewer) utilities already laid in the street.

III ) Road Material: Assess the type of material on the street—whether it's asphalt, PCC, or brick paving—since it affects construction methods and costs.

For Planning New Cities

I) Watershed Analysis: Determine the natural water flow direction to align road gradients and gravity-based flows (sewer and storm systems) accordingly.

II ) Terrain Assessment: Analyze the terrain of the built-up area, considering whether it’s flat or hilly, to guide utility network design.

By paying attention to these details, you can ensure that your designs are practical, efficient, and sustainable.

Tools for effective site visits:

?? Optimize Your Site Visits with Smart Tools and TechnologyAs a wet utilities design engineer, capturing accurate site data during visits is crucial for creating precise and efficient designs. Here's a workflow to enhance your site visit process using simple tools:

?? Tools for Taking Pictures on Site:

I) GPS Map Camera App: Automatically tag your photos with GPS coordinates, making them location-accurate.

II) Timestamp App: Adds date and time stamps to your images for better documentation.

??? Post-Site Visit Workflow:

Transfer Images: Use a data cable to copy all your site images to your computer.

Import to Global Mapper: Drag and drop your GPS-tagged images into the software.

Global Mapper will place them on exact coordinates.

Create KMZ/KML Files: Export your photos as KMZ/KML files directly from Global Mapper.

Visualize in Google Earth Pro: Open the KMZ file in Google Earth Pro for a detailed and interactive visualization of your site.

?? This approach not only saves time but also ensures your design process is based on accurate, georeferenced data.

3?? Key Steps in Design Engineering

We will first establish the design criteria by defining the minimum and maximum velocity, as well as the minimum and maximum pressure, to ensure safe and efficient system operation.

· Defining Road Cross-Sections

Creating road cross-sections ensures proper allocation of space for utilities such as sewerage, potable water, and stormwater. Proper planning ensures all services fit seamlessly within the Right of Way (ROW).

· Conceptual Network Design

Gravity networks (sewerage and stormwater) are conceptually marked, aligning flow direction with road slopes or watersheds, leading to Sewage Treatment Plants (STPs) or existing streams.

· Manhole Placement

Manhole spacing is determined by standards provided by the concerned authority, with spacing based on pipe diameters to ensure functionality and ease of maintenance. As the diameter increases slope decreases.

· Drafting and Hydraulic Modeling

• CAD Drafting: Draftsmen map utility layouts based on road designs and Road X-Section.
• Hydraulic Modeling:SewerGEMS: Simulates sewer networks and breaks lines at manhole placements using batch pipe splits and property interference tools.
• Water Supply Analysis in WaterGEMS: Analyzes pressure variations and water hammer effects by breaking pipelines into smaller segments of each 10 units for a detailed study.

· Finalizing Designs in SewerGEMS and WaterGEMS

• Sewerage Designs: Design constraints that depend upon the standard we are following and hydraulic features are modeled in SewerGEMS.
• Potable Water Designs: Hydraulic analysis is done in WaterGEMS, while diameter selection and looping are performed manually to ensure precise design.

· Material and Demand Calculations

• Pipe Material Selection: Based on technical, operational, structural, and cost considerations, adapted to the terrain (hilly or plain) for both gravity and pressure networks.
• Demand Calculations: Tailored to specific area requirements using SewerGEMS and WaterGEMS.

There are normally three methods in waterGEMS or sewerGEMS for Assigning Demands(Loads).

1) Property Connection( SewerGEMS) and Customer Meter(WaterGEMS). This method is usually used for Planned Areas.

2) Theisen Polygon. This method is usually used for large unplanned Urban Areas.

3) Unit Load(Count) Method. This is used for small towns or villages in which we equally divide the demand( on every Node in case of WaterGEMS & on every Manhole in case of SewerGEMS).

Peak Factors Calculation for Potable water & Wastewater

Peak factors are essential in designing water distribution and sewerage networks to account for variations in flow.

• Potable Water Supply: The peak demand is calculated by multiplying the average water demand by a peak factor of 2.25. This ensures the distribution network is designed to handle the maximum expected flow during high-demand periods.
• Sewerage System: For sewerage, peak factors are determined using Harmon's Formula, which relates peak factors to population. As wastewater flow increases, the peak factor decreases, reflecting reduced variability in larger systems. This principle ensures the network is appropriately sized for both low and high-flow conditions.

4??Connecting SewerGEMS with Civil 3D/InfraWizard for BIM Model or Sewerage Profiles.

Efficiently managing sewerage networks is key to successful infrastructure projects. By integrating SewerGEMS with Civil 3D or InfraWizard, you can achieve seamless BIM workflows, generate accurate sewerage profiles, and enhance collaboration across teams.

5??Review and Approval (Vetting)

The designer must ensure that the entire network complies with the relevant design standards, including velocity and pressure checks, sewer pipe depth evaluation (to assess the need for a sewage lift station), pump analysis, and loop network validation.

Finalized designs and drawings are printed and submitted to the Design Manager for review. This ensures all designs meet technical and quality standards before implementation.