At The Concept Group, we provide comprehensive civil engineering services to support residential development projects of all sizes. Our experienced team has the expertise and knowledge to assist with every phase of your project — from initial planning through final construction.

Our civil engineering services include:

• Site Layout Design
  Efficient, code-compliant site plans that maximize land use and functionality.
• Utility, Stormwater Drainage, and Sewer Design
  Complete utility planning, stormwater management systems, and sanitary sewer infrastructure tailored to your site’s needs.
• Erosion Control Design
  Effective erosion and sediment control plans to protect your site and meet regulatory requirements during construction.
• Grading and Paving Plans
  Precise grading and paving designs to ensure proper drainage, access, and long-term durability.

We work closely with developers, architects, and local agencies to deliver practical, cost-effective, and sustainable solutions for your residential projects.

At The Concept Group, our professional engineers have developed and maintained a high level of expertise in hydraulic and hydrologic analysis, as well as stormwater management system design. We offer a comprehensive range of services to support the effective management, treatment, and control of stormwater for development projects.

Our stormwater management services include:

• Hydrologic and Hydraulic (H&H) Modeling
  Detailed analysis and modeling of stormwater runoff, flow paths, and system capacities to support site design and regulatory compliance.
• Water Quality Best Management Practices (BMPs) Design
  Design of stormwater treatment systems to improve runoff water quality and meet environmental protection standards.
• Stormwater Detention BMPs Design
  Planning and design of detention and retention facilities to manage stormwater volume, control peak flows, and reduce downstream impacts.
• Infiltration Testing
  Field testing to determine subsurface infiltration rates, supporting the design of infiltration-based stormwater solutions.
• Soil Analysis
  Onsite soil classification and laboratory analysis to evaluate infiltration potential and suitability for stormwater management facilities.

Our integrated approach ensures that every project benefits from technically sound, environmentally responsible, and cost-effective stormwater management solutions.

At The Concept Group, we provide integrated civil engineering and land development services for residential projects. We work with developers, architects, and homeowners to support projects from planning to completion.

Our services include:

• Feasibility Studies
• Entitlement and Permit Acquisition
• Construction Management Support
• Erosion Control BMP Inspections
• Certification of Drainage BMPs
• Preparation of As-Built Drawings

We deliver practical, efficient solutions to keep your project moving forward.

Infiltration testing is a key component of geotechnical site investigations, conducted to evaluate the rate at which water infiltrates into subsurface soils. This testing provides essential data for the design of stormwater management systems, including infiltration basins, permeable pavements, bio-retention areas, and other sustainable drainage solutions.

The Concept Group offers infiltration testing services for a wide range of development projects. Our in-house team of experienced field technicians and engineers provides comprehensive testing and analysis to support project design and regulatory compliance.

The geotechnical infiltration testing process typically includes:

• Site reconnaissance and selection of test locations based on proposed development plans and existing surface conditions.
• Excavation or boring of test holes to predetermined depths, typically within or near the proposed infiltration areas.
• Performance of infiltration tests using industry-approved methods, such as the EPA Falling Head Test or the Department of Ecology’s Pilot Infiltration Test (PIT).
• Monitoring of water levels and infiltration rates over a set period, with data collection to determine steady-state infiltration rates.
• Soil classification and logging at each test location, correlating infiltration performance with soil type, structure, and moisture content.

Our testing services provide reliable, site-specific data to inform stormwater system design and ensure project success.