Hydraulic & Hydrologic Modeling

Every infrastructure project that interacts with water relies on a sound understanding of hydrologic and hydraulic processes long before construction begins. Through detailed analysis and modeling, engineers determine design flows, evaluate system performance under real-world and extreme conditions, assess flood risks, and establish the criteria for sizing critical infrastructure components. Done properly, hydraulic and hydrologic studies provide the quantitative foundation that guides planning, design, permitting, and long-term asset performance.

DLZ brings advanced computer modeling and hands-on engineering expertise to hydraulic and hydrologic analysis across stormwater, wastewater, drinking water, and tunnel systems. Whether you’re sizing a detention basin, modeling a combined sewer system, or evaluating surge risk in a tunnel, our analysis gives you the clarity and confidence to move forward — and the documentation to satisfy regulators, funders, and stakeholders along the way.

Featured Capabilities

Stormwater & Wastewater

From culverts and channels to detention basins and combined sewer systems, DLZ applies hydrologic and hydraulic modeling to size infrastructure correctly and plan for long-term performance. Our watershed analysis and master planning services help communities understand system-wide conditions and prioritize improvements with confidence.

Drinking Water Systems

Reliable drinking water delivery depends on a system that’s been thoroughly analyzed under real conditions. DLZ performs steady state and extended period modeling simulations, fire flow analysis, capacity assessments, and water loss audits — supporting master planning and ensuring storage, pressure, and distribution infrastructure performs as needed across simple and complex systems alike.

Tunnels & Special Structures

Tunnels and special hydraulic structures such as dams require a level of analytical precision that goes beyond standard modeling. DLZ applies computational fluid dynamic modeling to evaluate flow behavior in complex environments, and performs surge analysis to identify and mitigate the pressure risks that rapid filling can create in tunnel systems.

Computer Simulation & Modeling

DLZ uses current industry-standard software (including HEC-RAS, SWMM, and others) to simulate how water moves through river systems and infrastructure under a full range of storm and flow scenarios. These simulations support better design decisions, reduce risk, and provide defensible documentation for regulatory review and project approvals.

Water Quality Facility Calculations

Sizing detention basins and water quality treatment structures requires precise understanding of both hydrology and water quality objectives. DLZ performs the detailed calculations needed to design facilities that meet regulatory standards and protect the health of receiving waterways.

Hydrologic Analysis

Understanding how water behaves in a watershed is the essential first step in any water-related infrastructure project. DLZ analyzes rainfall patterns, runoff characteristics, and watershed response to determine the flows your systems must be designed to handle, using advanced computer simulations and engineering calculations.

Hydraulic Analysis & System Sizing

From bridges and culverts to storm sewers, detention ponds, tunnels, and open channels, DLZ sizes every component to perform safely and efficiently under the full range of conditions it will face. Our analysis ensures your infrastructure is built right the first time.

Combined Sewer System Analysis

Combined sewer systems present some of the most complex hydraulic challenges in municipal infrastructure. DLZ models these systems in detail, supporting master planning efforts that identify capacity constraints, overflow risks, and the targeted improvements that reduce both regulatory exposure and community impact.

Related Work

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