CIVIL ENGINEERING PRODUCTION
Grading & Drainage
Site grading, stormwater management, and detention system production support built on your
engineer’s hydrology design.
Our Founding and Mission
Introduction
NexMEP Global LLC supports U.S. civil consulting firms with grading and drainage production, developing site grading plans, stormwater conveyance layouts, and detention or retention system documentation from your engineer’s hydrologic and hydraulic design. Our team carries grading and drainage documentation through each design phase while your licensed civil engineers retain full authority over stormwater management strategy, detention sizing, and drainage system design.
We work from the grading concept, drainage area delineation, and stormwater management approach your engineer establishes, producing coordinated documentation that reflects that design intent accurately, consistent with the precision this elevation-driven scope requires.
DESIGN ACCURACY & COMPLIANCE
Why This Service Matters
Site grading and drainage design directly affects how a site performs during storm events, and it must simultaneously satisfy building accessibility requirements, parking lot drainage, and stormwater management regulations that increasingly require detention or retention of runoff on site. A grading plan that is not carefully coordinated with building finished floor elevations, ADA accessible route requirements, and downstream drainage capacity creates problems ranging from ponding and accessibility non-compliance to regulatory non-compliance with stormwater permits.
Production support allows this elevation-intensive, detail-sensitive documentation to be developed carefully alongside the rest of the civil design, keeping grading, drainage conveyance, and detention system documentation synchronized as your engineer’s hydrologic analysis is refined.
Our Capabilities
Site Grading Plan Development
Establishing finished surface elevations for building pads, parking lots, drive aisles, and swales.
Stormwater Conveyance Layout
Drafting catch basins, inlets, storm sewer piping networks, headwalls, and outfall structures.
Detention & Retention Storage Design
Documenting surface ponds, underground storage pipe/chamber arrays, and outlet control structures.
ADA & Accessible Route Grading
Maintaining compliant running and cross slopes along pedestrian paths and accessible parking.
Cut/Fill & Earthwork Optimization
Coordinating surface models to balance site earthwork volumes and evaluate retaining wall needs.
Green Infrastructure & LID Detailing
Integration of bioretention basins, rain gardens, permeable pavers, and water quality structures.
Calculations
Engineering Calculations
Calculation methodology built for accurate, traceable HVAC equipment sizing.
Hydrologic & Hydraulic Pipe Sizing
Drainage area delineation, runoff coefficients, and storm pipe sizing based on design storm parameters.
Volume Verification & Water Quality Backup
Verification of storage volume stages, outlet structure hydraulics, and water quality treatment volumes.
Calculations
Systems We Support
Ventilation-related calculation support includes outdoor air rate compilation.
Conventional Storm Sewer Conveyance
Catch basin layouts, storm piping, manholes, and open channel swales.
Surface Detention & Retention Ponds
Dry detention basins, wet retention ponds, and sediment forebays.
Underground Stormwater Systems
Concrete vaults, modular plastic chambers, and large-diameter pipe networks.
Infiltration & Exfiltration Systems
Infiltration trenches, dry wells, and exfiltration pipe arrays.
Low Impact Development (LID)
Bioretention cells, vegetated swales, filter strips, and green infrastructure.
Complex Multi-Stage Control Structures
Weir walls, orifice plates, and multi-tier outlet control boxes.
Our grading and drainage production team combines surface modeling expertise with hydraulic precision, delivering permit-ready drainage packages that meet strict municipal stormwater regulations.
Calculations
Software, Workflow & Coordination
Rigorous backup calculations formatted directly for permit submission and QA/QC documentation.
Software & Production Workflow
Grading surfaces and pipe networks are developed dynamically in Autodesk Civil 3D using your firm’s standards. We utilize surface analysis tools to perform drop-point checks, verifying positive drainage at all critical entrances and curb lines.
Revit & AutoCAD Coordination
Finished floor elevations and perimeter grades are cross-checked against architectural Revit models. Accessible routes and curb ramps are verified to ensure running slopes and cross slopes remain fully ADA-compliant relative to architectural entry points.
Calculations
Systems We Support
Expertise across diverse equipment lines, hybrid configurations, and complex Electrical setups.
Site Grading & Utility Plans
Storm Sewer Plan & Profile Drawings
Detention & Control Structure Details
Hydrologic Backup & Spot Elevation Logs
Need Elevation-Critical Grading & Drainage Production Support?
Partner with NexMEP Global LLC for accurate Civil 3D surface modeling, ADA slope audits, and permit-ready drainage sets.
Our Core Philosophy
Typical Project Types
Commercial & Retail
Shopping plazas, commercial office parks, and standalone retail pad sites.
Multi-Family & Residential
Apartment complexes, residential subdivisions, and mixed-use developments.
Education & Healthcare
K-12 schools, college campuses, medical centers, and hospital additions.
Industrial & Logistics
High-bay distribution centers, warehouses, and heavy equipment storage yards.
Calculations
QA/QC Process
A rigorous, multi-tiered review structure ensuring accurate, clear, and error-free submittals.
Positive Drainage Verification
Surface analysis checks confirming positive slope away from building foundations and no unintended low points.
ADA Slope Limit Audits
Verification that accessible path running slopes (max 5%) and cross slopes (max 2%) comply with ADA rules.
Contour & Spot Elevation Audits
Secondary review checking spot elevations for logical consistency with proposed contour lines and spot flow arrows.
Why NexMEP Global LLC?
NexMEP Global LLC brings a dedicated production team with practical experience across standard and specialty ventilation systems, a consistent U.S. code and standards focus, and a multi-level QA/QC process that reduces rework during your engineer’s review cycle.