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Trenchless Technologies

Aging pipe infrastructure is one of the most pressing challenges facing municipalities today. The sanitary sewers, combined sewers, and stormwater conveyance systems buried beneath our communities are critical to public health and environmental protection — and when they fail, the consequences are costly and disruptive. DLZ brings specialized expertise in pipe condition assessment and rehabilitation design, helping communities understand what they have underground and make smart, defensible decisions about what to do next.

DLZ rehabilitation projects integrate civil, geotechnical, structural, and hydraulic disciplines to address the full complexity of existing pipe systems, including challenging access conditions and temporary flow control needs. From the first inspection through final construction oversight, DLZ provides the continuity of expertise that keeps rehabilitation programs on track and infrastructure performing for decades to come.

Featured Capabilities

Comprehensive Condition Assessment & Defect Coding

Understanding what’s happening inside aging pipes requires the right tools and a consistent methodology. DLZ applies CCTV, laser profiling, sonar, and multi-sensor inspections alongside standardized National Association of Sewer Service Companies (NASSCO) coding to quantify defects, structural condition, and maintenance issues — then integrates findings into GIS for a clear, system-wide picture of pipe health.

Structural & Hydraulic Capacity Evaluation

Knowing a pipe is deteriorating is only the beginning. DLZ evaluates remaining structural capacity, collapse risk, and load ratings alongside hydraulic performance impacts, which helps identify the bottlenecks and vulnerabilities contributing to sanitary sewer overflows, combined sewer overflows, inflow and infiltration, and pipe surcharging.

Prioritization & Capital Planning

Not every pipe can be rehabilitated at once, and not every defect carries the same risk. DLZ develops risk-based prioritization frameworks that weigh pipe condition, consequence of failure, and system criticality. The result: rehabilitation and replacement plans with realistic cost estimates and phasing strategies that align with budget cycles and community needs.

Rehabilitation Technology Selection & Design

Selecting the right rehabilitation method is as important as the design itself. DLZ evaluates and designs solutions across the full range of available technologies — including CIPP lining, sliplining, spray-on lining, pipe bursting, and open-cut replacement — matching the method to each pipe’s condition, access constraints, and long-term performance requirements

Constructability & Implementation Support

Rehabilitation projects in active systems demand careful coordination. DLZ evaluates access constraints, bypass pumping needs, and flow control strategies, then develops sequencing and traffic management plans that minimize disruption. Bid documents and contractor support keep implementation moving smoothly from award through construction.

Construction Oversight & QA/QC

The quality of a rehabilitation project is only as good as the oversight behind it. DLZ performs submittal reviews, liner installation observations, and material testing verification to confirm compliance with specifications and long-term performance expectations — maintaining rehabilitation records and conducting follow-up inspections to close the loop on every project.

Related Work

Water Asset Management Program, West Bloomfield Township

West Bloomfield Township

, Michigan

CCTV and NASSCO into GIS Geodatabase, Genesee County

Genesse County

, Michigan

Shoreline Storage Tunnel Project, NEORSD

Cleveland

, Ohio

East Franklinton Improvements

Columbus

, Ohio

Related Capabilities

Kyle

Riggenbach, PE

Project Manager

Ohio

Anthony

Paglia, PE