Erosion Control Planning: LDA & NPDES permits, Level 3 Soil Surveys & Septic Design

If you are planning to disturb more than an acre of land, you are required to obtain a Land Disturbing Activity (LDA) permit. When applying for a LDA permit and submitting a Notice of Intent (NOI) under the applicable National Pollution Discharge Elimination System (NPDES) General Permit, you are required to satisfy several criteria. Two important criteria to have in place are Erosion Sedimentation and Pollution Control Plans (ESPCPs) and structural Best Management Practices (BMPs). 

At Mill Creek Environmental we have assisted a variety of clients including local and municipal governments, utility contractors, real estate developers, custom home builders and private landowners, with all types of planning for LDA permits and NPDES compliance issues.

What is an NPDES permit?

The Clean Water Act (CWA) prohibits anyone from discharging pollutants into the water of the United States, unless they have an NPDES permit. This includes everything from industrial wastewater to storm water runoff from construction sites. The general permit for construction activities requires the permittee to complete these actions:

  • Develop and follow an Erosion, Sedimentation and Pollution Control Plan (ESPCP);
  • Install and maintain structural Best Management Practices (BMPs) to limit the migration of sediment from the project area;
  • Conduct inspections of the BMPs and project area according to a set schedule;
  • Collect samples of stormwater where it runs off the project area and analyze the turbidity to demonstrate compliance with the permit; and,
  • Maintain records of daily rainfall amounts, inspection reports, turbidity measurements and all other documentation related to the permit.

What is an ESPCP?

At Mill Creek Environmental we compile ESPCPs to satisfy the requirements of LDA and NPDES permitting for land disturbing activities. Our project team consists of Registered Professional Geologists, Certified Level II Designs Professionals, Certified Level II Plan Reviewers and Certified Level 1A and 1B Inspectors who will complete the following to produce your ESPCP:

  • Visit the site to visually inspect the project area and identify any potential areas of concern prior to plan preparation;
  • A plan will be prepared to comply with the requirements of the applicable NPDES General Permit;
  • The applicable Plan Checklist as established by the relevant Water Conservation Commission will be completed and will accompany the plan set;
  • The installation of the initial sediment storage requirements and perimeter control best management practices (BMPs) will be inspected within seven days after installation as required by the permit; and,
  • Plan sheets will be prepared, stamped and signed by a licensed Design Professional – the components of an ESPCP include:
    • Cover sheet with detailed property information, table of contents, signature and stamp of the Design Professional
    • ESPCP Phase 1, 2 and 3
    • Erosion Control Notes and Details
    • The Water Control Commission ESPCP Checklist
    • Inspection and record keeping requirements

Soil Surveys and Septic System Designs

To obtain a permit for an on-site Sewage Management System (a Septic System), a Level 3 Soil Survey (or Perc Test) must be conducted to determine whether your soil is suitable for a Septic System to be installed. For difficult lots or poor soil areas, a Level 4 Soil Survey can be conducted – a high intensity soil survey that provides much more detail than a Level 3 Soil Survey. 

The Soil Survey evaluates a soil’s ability to percolate (“perc”) wastewater from a septic tank and also provides information on depth of rock or groundwater. We hand auger four borings over approximately one acre, strategically placed in the proposed drain field areas where you plan to build taking into consideration site-specific features such as slopes, wells, creeks and springs. We classify or identify the soils as we dig until reaching a depth of six feet (or refusal) at each bore hole. Each different soil type has a particular absorption rate that is used to determine stability and suitability for a conventional (standard) septic system. We also map each boring and applicable setbacks to the site features. 

Mill Creek Environmental has completed thousands of Level 3 and Level 4 Soil Surveys for both residential and commercial real estate transactions and Septic System Permits. If the initial analysis shows that a conventional Septic System is not suitable, there are other systems that can be utilized such as a mound or drip system – rest assured we will work hard to find a solution!

Our licensed Geologists, working closely with professional engineers, can also design a Septic System for difficult soils and terrains such as shallow bedrock, small lots and high water tables as well as provide alternatives and solutions for failing Septic Systems.

We undertake the Soil Survey first, where an MCE Scientist works under a licensed Professional Geologist to perform the field work and write the report. A typical residential Level 3 Soil Report describes our findings and includes:

  • A table that lists all the data collected at each boring;
  • A classification code for each boring;
  • A map of the lot showing where each boring is and all the pertinent site features and setbacks; and,
  • A summary letter that includes our recommendations

Once the Soil Survey Report is completed, if needed, we can prepare a Septic System Design that will include the proposed system size, design calculations, system layout, equipment specifications, construction details, installation notes and maintenance requirements. All work will be completed in accordance with local rules for Onsite Sewage Management Systems.

You can rely on Mill Creek Environmental for all of your erosion control planning and septic system designs. Contact us today on 706.579.1607 for a no obligation cost estimate.

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