Underground Drainage Network Retrofit — Narsannapeta & Srikakulam Villages, Andhra Pradesh
Project Overview
- Client: Srikakulam District Municipality, Government of India
- Location: Rural villages in Narsannapeta & Srikakulam District, Andhra Pradesh, India
- Scope: Retrofitting a modern underground drainage network to serve 500 households as part of a rural sanitation initiative
Summary
Under a government sanitation drive, the Srikakulam District Municipality commissioned a retrofit of old lavatory pit systems in five rural villages. The project aimed to deploy a gravity-based underground drainage system to improve health outcomes, reduce groundwater contamination, and upgrade rural infrastructure.
The coastal terrain presented major challenges high water table, saline soils, and existing village structures like house platforms and electric poles made the work complex. Additionally, community cooperation was critical, since digging and construction would disrupt daily life. Through careful design and local engagement, the project was executed efficiently while minimizing long-term maintenance needs
Implementation Steps
- Marking for Trench Cutting
- Manual marking using line dori across narrow village lanes
- Avoided interference with existing utilities and household structures
- Excavation
- Trenches excavated to ~1.5 m depth
- Manual labor carefully navigated around village infrastructure
- Laying CC Bricks
- Anti-corrosive coated CC bricks used to line trench base
- Stabilized trenches against saline soil deterioration
- PCC Bed at Chambers
- Plain-cement concrete beds created for manhole chambers
- Provided a stable base and prevented settlement
- Pipe Laying
- Corrosion-resistant HDPE pipes laid with a 1:200 slope for efficient gravity flow
- Ensured durability and low maintenance
- Concrete Pegs
- Placed every 3 m to anchor pipes and secure them against soil or water movement
- Risers & Temporary Covers
- Installed risers at inspection points
- Used temporary cement-bag covers during construction for safety and cost control
- Installed risers at inspection points
- Household Connections
- Each of the 500 homes was connected to the drainage network
- Close coordination with residents to reduce disruption
- Each of the 500 homes was connected to the drainage network
- Refilling & Pathway Restoration
- Trenches backfilled with local soil, compacted to restore village paths
- Ensured minimal long-term impact on daily life
- Frame & Cover Installation
- Lightweight composite covers installed at manholes
- Designed for durability and cost-effectiveness
Challenges and Solutions
- High Water Table
The coastal villages had significant groundwater seepage during construction. The team used a well-point dewatering system to manage water and keep trenches dry. - Saline Coastal Soil
To resist corrosion, the design used HDPE pipes and applied anti-corrosive coatings on manhole bricks, ensuring long-term material resilience. - Existing Infrastructure
Pre-construction surveys mapped out lavatory pits, poles, and house platforms. In sensitive zones, trenchless drilling methods minimized disruption. - Community Engagement
Villagers were initially hesitant due to construction disruption. Leverage of local labor, intensive awareness campaigns, and transparent communication helped build trust and cooperation.
Outcomes
- The project was completed in about 5 months, on time and within budget.
- Sanitation was significantly upgraded for 500 households, reducing health risks and improving environmental conditions.
- The system is built for long-term reliability: HDPE pipes + anti-corrosive construction reduce future maintenance.
- Lightweight covers and local labor kept costs low, aligning with municipal budget constraints.
- The retrofit also serves as a model for sustainable rural infrastructure, supporting broader government sanitation goals
