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Overview

Stormwater Engineering Done Right the First Time

Stormwater is where projects get delayed, budgets get blown, and permits get denied. It's also where three decades of engineering discipline pays off, the difference between a design that clears review on the first pass and one that comes back with 40 comments.

Our team provides full stormwater engineering services across North Carolina, from early drainage concepts through sealed stormwater reports and construction-phase certifications. Every design meets NCDEQ, local, and watershed-specific standards, with hydrology models calibrated to the correct storm events and SCMs sized to the correct water quality volume.

  • NCDEQ-compliant stormwater design for all watershed classifications
  • CFM-certified floodplain and stormwater expertise
  • Full hydrology modeling (SCS, Rational, Modified Rational methods)
  • SCM design: bioretention, wet ponds, dry detention, level spreaders, sand filters
  • Protected watershed experience (Randleman, Jordan Lake, Falls Lake, Neuse)
What's Included

Complete Stormwater Services

Nine integrated deliverables covering every aspect of stormwater engineering from concept to construction.

Water Quality Volume (WQv) Calculations

Site-specific water quality volume calculations per NCDEQ standards, accounting for built-upon area, impervious coverage, and watershed classification.

SCM Design & Sizing

Bioretention cells, wet ponds, extended detention, dry detention, sand filters, level spreaders, and combined systems, sized and detailed for NCDEQ approval.

Hydrology Modeling

Full SCS methodology for drainage areas, curve numbers, time of concentration, and peak flows. Pre- vs post-development analysis for 1-, 2-, 10-, 25-, and 100-year storms.

Storm Sewer Design

Rational method storm sewer sizing, Manning's equation pipe design, inlet spacing, gutter spread analysis, and junction loss calculations.

Stage-Storage & Routing

Stage-storage curves for detention basins and SCMs, outlet structure design, riser/weir sizing, and full hydrograph routing through the SCM system.

Outlet Structure Design

Riser structures, orifice plates, weirs, emergency spillways, underdrain systems, and trash racks, sized for the required drawdown time and designed for constructability.

Stormwater Narrative & Report

Comprehensive stormwater reports meeting NCDEQ and local submittal requirements, narrative, calculations, drainage area maps, stage-storage tables, and certifications.

10% Downstream Analysis

Downstream analysis studies required for projects discharging to sensitive waters or exceeding impact thresholds. Documented per NCDEQ and local requirements.

As-Built Certifications

Engineer-of-record SCM certifications, as-built stormwater inspections, and compliance letters for NCDEQ and local jurisdiction closeout requirements.

Watershed Expertise

Protected Watershed Experience

North Carolina has some of the most restrictive protected watershed rules in the Southeast. We have active experience in all of them.

Randleman Lake

High Point, Greensboro, Archdale service areas

Jordan Lake

Chapel Hill, Carrboro, Burlington, Alamance

Falls Lake

Raleigh, Durham, Wake County, Granville

Neuse Basin

Wake, Johnston, Wayne County regulated areas

Why Civil Builders Engineering

What Sets Our Stormwater Work Apart

CFM Certified

Our Certified Floodplain Manager credential brings specialized expertise in flood hydrology, base flood elevation analysis, and NFIP compliance that most civil firms don't have.

First-Pass Approval

Our stormwater packages are built to clear review on the first pass, calibrated models, thorough narratives, and the right supporting calculations before the review engineer asks.

17 Jurisdictions

Active experience with stormwater standards across 17+ NC jurisdictions, each with their own quirks, submittal requirements, and preferred SCM types.

Ready to Start?

Let's Design Your Stormwater System

Whether you need a quick feasibility check or a complete permit submittal, we can help.