Spreadsheet: 57691295-2c8c-4fb6-8ae4-22e160938c01
Sheet: Instructions

 |  | Introduction
 |  |  | This workbook was created to assist in determining the annual hydraulic loading rate for single-family residence wastewater irrigation systems subject to 15A NCAC 02T .0600.
 |  |  | All single-family residence wastewater irrigation systems shall be designed in full accordance with 15A NCAC 02T .0600, the Single-Family Residence Wastewater Irrigation System Calculation Policy and all other applicable Water Quality Permitting Section policies.
 |  |  | Online downloads
 |  |  |  | 15A NCAC 02T rules: |  | http://portal.ncdenr.org/web/wq/aps/lau/rules
 |  |  |  | Water Quality Permittting Section's Non-Discharge Permitting Unit policies: |  |  |  |  |  |  | http://portal.ncdenr.org/web/wq/aps/lau/policies
 |  |  | This workbook consists of 5 worksheets: |  |  |  |  | http://h2o.enr.state.nc.us/lau/policies.html | http://h2o.enr.state.nc.us/lau/policies.html | http://h2o.enr.state.nc.us/lau/policies.html | http://h2o.enr.state.nc.us/lau/policies.html
 |  |  | 1) | Instructions
 |  |  | 2) | Project Information Worksheet
 |  |  | 3) | Potential Evapotranspiration (PET) Worksheet
 |  |  | 4) | Precipitation Worksheet
 |  |  | 5) | Irrigation Area Calculations worksheet
 |  |  | In addition to the instructions below, additonal information is provided on each worksheet. These instructions will appear when you place your cursor over a cell that is marked with a small red triangle on the upper right side of the cell.
 |  |  |  | Hold cursor over this cell.
 |  |  | Once the workbook is fully filled out, print out a hard copy of worksheets 2, 3, 4, and 5 for inclusion with the soil scientist evaluation.
 |  |  | This workbook was created using Excel 2000. In order for the workbook to function correctly, the macros must be enabled when the workbook is first opened.
 |  | Instructions
 |  | General Information
 |  |  | Each worksheet contains colored cells, each of which have specific uses.
 |  |  |  |  | Green cells contain information and should not be altered in any way.
 |  |  |  |  | Blue cells require data input.
 |  |  |  |  | Yellow cells are linked to other cells and will be automatically calculated.
 |  |  |  |  | Cells marked with a red triangle contain instructions that will appear once the cursor is held over the cell.
 |  |  | The Project Information, PET, and [NAME] should be completed prior to working on the Irrigation Area Calculations Worksheet. Many cells in the Irrigation Area Calculations Worksheet will automatically insert data from the other worksheets.
 |  | Project Information Worksheet
 |  |  | This worksheet serves as a cover sheet for the printed workbook.
 |  |  | Fill in information for the following items:
 |  |  |  | Project Name - Input the name of the permittee here. This information will be automatically inserted in all the other worksheets.
 |  |  |  | Facility Address - Input the facility mailing address. If unknown input the name of the development and lot number.
 |  |  |  | County - Input the name of the county the facility will be located in.
 |  |  |  | Prepared by - Input the name of the licensed soil scientist sealing the soil scientist evaluation.
 |  |  |  | Project Design Flow - Input the daily wastewater flow for the project (gallons per day). The flow for the project should be based upon the number of bedrooms of the single-family residence. (see [NAME] chart) The Project Design Flow value will be automatically input into the Irrigation Area Calculations Worksheet.
 |  | Potential Evapotranspiration (PET) Worksheet
 |  |  | This worksheet utilizes the Thornthwaite method to calculate the PET for each month of the year. Review the Single-Family Residence Wastewater Irrigation System Calculation Policy if an alternative method is to be used for calculating PET.
 |  |  | The following information will be required:
 |  |  |  | Temperature Data - Input the average temperature for each month of the year. The average monthly temperature values used in this calculation are required to be from the same data source and time period as the precipitation data used.
 |  |  |  | Latitude - Input the degrees latitude of the project site. This will enable the worksheet to automatically calculate the daylight hours and heat index for each month of the year.
 |  |  | If this worksheet is fully completed, the calculated PET for each month of the year will be automatically inserted into the Irrigation Area Calculations Worksheet. If an alternative method is utilized, the PET will need to be manually entered on the Irrigation Area Calculations Worksheet.
 |  | Precipitation Worksheet
 |  |  | This worksheet calculates the 80th percentile precipitation for each month of the year.
 |  |  | The following information will be required:
 |  |  |  | Precipitation Data
 |  |  |  |  | Source: | The source data is required to be representative of the area where the facility will be located and shall be based on long-term (minimum of 30 years) data. The average monthly precipitation values used in this calculation are required to be from the same data source and time period as the temperature data used in the PET calculation.
 |  |  |  |  | Average Monthly Precipitation - Input the average precipitation for each month of the year.
 |  |  |  |  | 80th Percentile Annual Precipitation - Input the 80th percentile annual precipitation
 |  | Irrigation Area Calculations Worksheet
 |  |  | This worksheet calculates the Annual Hydraulic Loading Rate and the amount of irrigation area that will be required. PET and 80th percentile precipitation values for each month of the year will be automatically filled out if the PET and Precipitation Worksheets have already been completed.
 |  |  | The following information will be required:
 |  |  |  | SFR Loading Rate Group - Input the SFR Loading Rate Group. To determine which SFR Loading Rate Group the wastewater irrigation area should be assigned to, compare the geometric mean of Ksat data from the most limiting horizon with the SFR Loading Rate Table. Each SFR Loading Rate Group has an allowable range for the annual hydraulic loading rate. System designs that exceed the maximum value for the annual hydraulic loading rate for a particular SFR Loading Rate Group shall require additional documentation.
 |  |  |  | Limiting Soil Ksat - Input the geometric mean of Ksat data from the most limiting horizon.
 |  |  |  | Drainage Coefficient - Insert the drainage coefficient assigned to the irrigation area. Values for this drainage coefficient shall not exceed 1.0 (100%).  Considerations for the drainage coefficient shall include reliability and consistency of Ksat data, depth to seasonal high water table (apparent or perched), depth to the restrictive horizon, slope, landscape position, inclusions of minor amounts of more limiting soils, etc.
 |  | Soil Series Tables
 |  |  | Four soil series tables have been included with this workbook. These tables are grouped by soil parent material and provide a rough estimate of the SFR Loading Rate Group for the soil series that are commonly found in areas where single-family residence wastewater irrigation systems have been historically permitted. These tables should not be used to determine the SFR Loading Rate Group. Actual assignment to a SFR Loading Rate Group for each 15A NCAC 02T .0600 permit application shall be determined by the geometric mean of in-situ saturated hydraulic conductivity data collected in the most restrictive horizon for each soil mapping unit.