The main factors considered when determining drainage class are soil color patterns, texture, and landscape position. The percolation test is designed to determine the suitability of a site for a subsurface private sewage disposal system (i.e. Somewhat poorly and poorly drained soils are common on low flats and floodplains, and are often tile drained to enhance agricultural production. © Copyright 2014, RTF Associates, Inc. “If there is a short (less than 60 days) timeframe to do the necessary due diligence (time for inspections of the property and improvements), a perc test can be performed much faster. RTF Associates, Inc. This variable color pattern indicates how high the seasonal high water table (SHWT) reaches in a soil. The hole is filled with approximately 12 inches of water to conduct the test. The percolation test consists of a hole 6-12 inches wide, dug in the designated area of a proposed septic system. Interpreting Your Soil Evaluation for Septic System Suitability . The Health Code provides a simple table that determines the size of the system based on the measured perc rate and the number of bedrooms in the home. The hole is filled with approximately 12 inches of water to conduct the test. The State Code specifies that at least two feet of separation should exist between the bottom of the septic field and the limiting layer (three feet in coarser-textured soils). These tests are usually performed by a soil scientist, engineer, or land surveyor. Consistence is a measure of how easily soil can be crushed between the thumb and forefinger. A percolation Test fails if the results are under 15 or over 100 seconds/mm. When a soil is frequently saturated (poorly drained), the iron is dissolved and leached away, leaving a gray color that is the base color of the soil particles. Using soil evaluations to assess site suitability for septic systems is becoming more common in Illinois, although many terms and abbreviations used by soil classifiers are unfamiliar to those not in the field of soil science. This information can help you correlate perc rates that may be more familiar to you with soils information. Introduction. A soil series is equivalent to a plant or animal species, in that a series represents a specific type of soil that can occur over a large geographic area. Silt loam and silty clay loam textures are very common in Illinois, having formed in loess parent material. The term “redox” comes from a combination of the terms “reduction” and “oxidation”, that are natural chemical/biological processes affecting iron and other minerals in the soil. A drainage field or mound serving a wastewater treatment plant or septic tank should be located: Brown, yellowish, or reddish colors are mainly the result of precipitated iron (essentially rust) that coats soil particles. Soil testing is also useful for identifying contaminated sites (e.g., elevated levels of lead). The subsoil, where clay accumulates, blocky and prismatic structure develops,and colors are variable is called the B horizon. The average percolation test times for three tests are then averaged which determines the size of the septic system. Drainage class describes the relative wetness of a soil prior to modification by drain tile or other means. In general, the lowest loading rate observed in the upper 30 to 42 inches of the soils examined is used for septic system design and sizing. Soil colors are described through use of the Munsell soil color charts. (410) 876-1222 1.27 Part H2 of the Building Regulations 2000: Drainage and waste disposal (go to page 32) states that. Layers within the soil that differ in color, clay content, or other ways are divided into horizons. The substratum, which consists of relatively unweathered soil material, is called the C horizon. CHAPTER 4: ANALYSIS AND INTERPRETATION OF RESULTS 4.1 INTRODUCTION To complete this study properly, it is necessary to analyse the data collected in order to test the hypothesis and answer the research questions. The numbers on the soil test report, together with the description of the nutrient content in the soil, can indicate if the predicted crop response to fertilizers will be favorable or not. Somewhat excessively and excessively drained soils usually combine these features with high contents of sand and/or gravel. The CivilWeb Soakaway Design Spreadsheet includes a tool for recording percolation test data and calculating the infiltration rate in accordance with BRE 365. Interpreting Your Soil Test Results. The same goes for failing. These terms include sand (s), loamy sand (ls), sandy loam (sl), sandy clay loam (scl), loam (l), clay loam (cl), silt loam (sil), silty clay loam (sicl), silty clay (sic), and clay (c). If you have further questions or would like to learn more details about soils and their interpretations, please feel free to contact any member of the Illinois Soil Classifiers Association. A perk test assignment will involve a number of different steps, and each is important. These limiting layers include bedrock, the seasonal high water table, dense soils with slow permeability, and sandy or gravelly soil with very rapid permeability. Ramblin Pines Campground Stormwater Management. Results are most often measured using age-based norms. Generally, less than 30 minutes is ideal in Carroll County. The Soil Group is determined by looking at a soil horizon’s texture, structure, consistence, and parent material, and using that to assign a sewage loading rate in gallons per square foot per day. Information supplied by the Illinois Soil Classifiers Association. Slopes often change rapidly over a short distance. Each of these master horizons can be subdivided if characteristics within them vary (for example, A1 and A2). Structure is ranked on a scale of 0 to 3 (structureless, weak, moderate, strong). Many counties utilize the Private Sewage Disposal Licensing Act and Code (State Code) issued by the Illinois Department of Public Health as their guidance for methods to conduct soil investigations, although some counties have slightly different requirements based on local ordinances. A light-colored E horizon lies near the surface of some soils as well, particularly on land that is or has been wooded. This section explains abbreviations and topics often found in soil evaluation reports, and discusses how various soil characteristics affect water flow out of septic systems into the soil. fax: (443) 289-8942, Experienced Land Surveyors and Excavators Conducting Percolation Tests in Maryland Since 1972. This portion of the report describes the property location, current use, and date of investigation. If parent materials change within the soil, it is signified with a number at the beginning of the horizon designation (examples include 2Bt and 3C). Structure size is also determined, and classified as fine (f), medium (m), and coarse (c). When clay content in soils exceeds 35% (heavy cl, heavy sicl, sic, or c textures), the soils are generally poorly suited for conventional septic systems because of slow permeability. Coatings of clay or organic matter are often deposited in the B horizons by water percolating downward. Here is a typical standard percolation test hole specification when soil testing for leachlines: Test holes shall be augered or excavated to within 13 inches of the actual test depth which corresponds to the anticipated depth of the leachline or the bed trench bottom.