GHOLSON ISD INFRASTRUCTURE PROJECT
GHOLSON ISD SANITARY SEWER SYSTEM UPGRADE
Project Location:
Gholson Independent School District, Gholson, Texas (McLennan County)
Project Overview:
Merritt Engineering Services provided comprehensive civil engineering design services for the complete replacement of the Gholson Independent School District's aging sanitary sewer infrastructure. The existing system consisted of seven individual septic systems that were outdated, undersized, and unable to meet the current and future wastewater demands of the school campus.
Our civil engineering team designed a modern, centralized gravity sanitary sewer collection system with a lift station and force main to consolidate all wastewater flows to a single discharge point. This project eliminated the operational and environmental liability of seven separate septic systems and delivered a reliable, code-compliant wastewater infrastructure solution sized to serve the district for decades to come.
Project Specifications:
Project Type
Sanitary Sewer System Replacement
Client
Gholson Independent School District
Location
Gholson, McLennan County, Texas
Existing System
Seven (7) Individual Septic Systems
Replacement System
Centralized Gravity Sewer + Lift Station + Force Main
(system outfalls to newly designed Sewer treatment Facility)
Key Components
Gravity Collection Mains, Lift Station, Force Main
Regulatory Compliance
TCEQ Wastewater Standards
Engineering Services Provided:
Topographic Survey & Existing Conditions Analysis
A detailed topographic survey of the school campus was performed to establish accurate existing ground conditions and identify constraints that would influence system layout and design. Survey data was used to determine gravity flow routing, manhole locations, and lift station siting.
Survey & Analysis Components:
Campus-wide topographic survey
Existing utility and septic system location
Drainage pattern and grade analysis
Constraint identification for pipe routing
Design surface model development
Utility Site Plans
Comprehensive utility site plans were developed showing the proposed sanitary sewer collection system in relation to existing campus utilities, buildings, and paving. These plans served as the primary coordination document for avoiding utility conflicts during construction.
Site Plan Elements:
Proposed gravity sewer main layout
Manhole locations and rim/invert elevations
Lateral connections to school buildings
Lift station site layout
Force main routing to discharge point
Existing utility conflict identification
Plan & Profile Sheets
Detailed plan and profile drawings were produced for all gravity sewer mains, showing horizontal alignment, pipe slope, cover depth, and manhole design. Profile sheets ensured the system was designed with adequate cover, proper grade for self-cleaning velocity, and compliance with TCEQ design standards.
Plan & Profile Design Elements:
Horizontal alignment and stationing
Pipe invert elevations and slopes
Cover depth verification
Manhole structure design
Conflict crossings with existing utilities
TCEQ minimum slope and velocity compliance
Lift Station Design
A wet-well/dry-well lift station was designed to collect gravity sewer flows from the campus collection system and pump wastewater through a force main to the designated discharge location. The lift station was sized to handle peak daily flows generated by school occupancy.
Lift Station Design Components:
Peak flow calculations for school occupancy
Wet well sizing and configuration
Pump selection and redundancy
Force main sizing and pressure analysis
Electrical and controls coordination
Emergency overflow provisions
Access and maintenance considerations
Project Challenges & Solutions
Challenge: Replacing Active Septic Systems on an Occupied Campus
Solution: Construction was scheduled during summer break when the campus was not in session, allowing full access to the site and uninterrupted installation of the gravity collection system without any impact to students or staff.
Challenge: Coordinating Seven Separate Building Connections
Solution: Utility site plans coordinated individual building lateral connections to the new gravity main, with invert elevations verified against existing building sewer stub-outs to ensure gravity flow from each structure.
Challenge: Flat Terrain Requiring Lift Station
Solution: Campus topography required a lift station to convey wastewater to the discharge point. Lift station location and force main routing were optimized to minimize pipe length and pumping head while providing accessible maintenance access.
Project Benefits for gholson isd
✓ Eliminated Seven Septic Systems:
Replaced aging, fragmented infrastructure with a single reliable, centralized wastewater system
✓ Environmental Compliance:
Modern system meets TCEQ standards, eliminating risks of septic system failure and potential groundwater contamination
✓ Capacity for Growth:
Centralized system is sized to accommodate current enrollment and future campus expansion
✓ Reduced Maintenance Burden:
One lift station and gravity collection system is far easier and less costly to maintain than seven separate septic systems
✓ Improved Reliability:
Redundant pump design at the lift station ensures continuous operation even during equipment maintenance
✓ Long-Term Infrastructure Investment:
New infrastructure provides Gholson ISD with a wastewater system designed to serve the district for decades