#611 ON-SITE TESTING AND EVALUATION

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1 OBJECTIVES: After completing this chapter, you will be able to... Describe the size and shape of a typical backhoe excavation. Safely evaluate a soil test probe. List the tools useful to an SEO in the fi eld. Identify the information included in a soil profi le description Revised MEETING THE CERTIFICATION, TRAINING, AND RESOURCE NEEDS OF PENNSYLVANIA S SEWAGE ENFORCEMENT OFFICERS

2 Soil Profile The soil test probe provides important information that is used to establish site suitability and absorption area selection. A proper review of the probe gives valuable insight to the actual soil conditions within a proposed absorption area FM-WSWM0290A Rev. 10/2003 COMMONWEALTH OF PENNSYLVANIA DEPARTMENT OF ENVIRONMENTAL PROTECTION BUREAU OF WATER SUPPLY AND WASTEWATER MANAGEMENT SITE INVESTIGATION AND PERCOLATION TEST REPORT FOR ONLOT DISPOSAL OF SEWAGE INSTRUCTIONS FOR COMPLETION OF THIS FORM ARE LOCATED ON THE REVERSE SIDE No. Municipality County Application Site Location Subdivision Name SUITABLE Soil Type Slope % Depth to Limiting Zone Ave. Perc. Rate UNSUITABLE Mottling Seeps or Ponded Water Bedrock Fractures Coarse Fragments Perc. Rate Slope Unstabilized Floodplain Other Fill SOILS DESCRIPTION: Soils Description Completed by: Inches 0 TO TO TO Description of Horizon Date: TO A soil profi le description is used to support the establishment of a limiting zone in a soil test probe. This description represents a characterization of the soil conditions that occur throughout the entire proposed absorption area. The SEO must examine a suffi cient number of soil test probes to accurately describe the soil conditions at each site. The SEO should follow standard procedures to safely evaluate and describe the soil test probes. TO TO PERCOLATION TEST: Percolation Test Completed by: Date: Weather Conditions: Below 40 F 40 F or above Dry Rain, Sleet, Snow (last 24 hours) Soil Conditions: Wet Dry Frozen Reading Reading Reading Reading Reading Reading Reading Reading *** Reading No. 1: No. 2: No. 3: No. 4: No. 5: No. 6: No. 7 No. 8: Hole No. Interval Yes No Inches of drop Inches of drop Inches of drop Inches of drop Inches of drop Inches of drop Inches of drop Inches of drop ***Water remaining in the hole at the end of the final 30-minute presoak? Yes, use 30-minute interval; No, use 10-minute interval. Calculation of Average Percolation Rate: Drop during Perc. Rate as Depth Hole No. final period Minutes/Inch of Hole The information provided is the true and correct result of tests conducted by me, Min performed under my personal supervision, Inch or verified in a manner approved by DEP. TOTAL OF MIN / IN = TOTAL NO. OF HOLES (S) Sewage Enforcement Officer White - Local Agency Yellow - Applicant Pink - Local DEP Office The soil profile description is recorded on the Site Investigation and Percolation Test Report for Onlot Disposal of Sewage. MEETING THE CERTIFICATION, TRAINING, AND RESOURCE NEEDS OF PENNSYLVANIA S SEWAGE ENFORCEMENT OFFICERS

3 Probe Excavation Typically, a soil test probe is excavated with a backhoe provided by the property owner or applicant. The local agency SEO does not usually provide these services. SIZE AND SHAPE A cross-section of a typical backhoe excavation is provided at right. Regardless of the actual dimensions, the excavation must provide safe access into the soil test probe. This chapter will review safety concerns associated with the examination of a soil test probe. A cross-section of a typical backhoe excavation. MEETING THE CERTIFICATION, TRAINING, AND RESOURCE NEEDS OF PENNSYLVANIA S SEWAGE ENFORCEMENT OFFICERS

4 Probe Safety The SEO must be able to safely enter and exit a properly excavated soil test probe. Safety must always be a priority. The SEO should never enter a probe if unstable soil conditions are noted or safe access is questionable. A cube of soil measuring 1 foot on a side weighs around 100 pounds. A cubic yard of soil contains 27 of these, or 2,700 pounds total. This weighs about as much as a midsized automobile. A trench wall collapse might contain 3 to 5 cubic yards of soil, weighing from 8,000 to 14,000 pounds. A person buried under only a couple feet of soil would experience enough pressure on the chest area to prevent their lungs from expanding. Suffocation would take place within about three minutes. Even if the person is rescued in time, the heavy soil loads are likely to inflict serious internal injuries. A person buried in earth as high as his diaphragm would not be able to dig himself out, and his chances of survival are low. If the face is even partially covered, death is almost certain. Source: A soil probe is excavated. MEETING THE CERTIFICATION, TRAINING, AND RESOURCE NEEDS OF PENNSYLVANIA S SEWAGE ENFORCEMENT OFFICERS

5 Probe Safety COMMON SAFETY ISSUES By following a few simple guidelines, the SEO will remain safe when evaluating a soil test probe. The following safety issues must be considered before entering the soil test probe excavation: Check for sidewall slumps or loose soil, especially in sandy, gravelly, or wet soil conditions. Make sure the soil removed by the backhoe is at least 2 feet away from the edge of the probe. Be sure the backhoe is turned off and the bucket is on the ground before entering the probe. Make sure the backhoe operator is aware that you are entering the probe. Always let others know where you are when you evaluate soil test probes. If a backhoe is working in a wooded area, be aware of the potential for falling trees or branches. MEETING THE CERTIFICATION, TRAINING, AND RESOURCE NEEDS OF PENNSYLVANIA S SEWAGE ENFORCEMENT OFFICERS

6 Examining the Soil Test Probe THE SOIL PROFILE Once the soil test probe has been dug, the SEO will select an appropriate area within the excavation to prepare a soil profi le description. To perform an accurate soil profi le description, the SEO should carefully choose the proper sidewall area in the soil test probe. This area should suffi ciently refl ect existing soil features and the shallowest limiting condition depth. The SEO should take the following steps to identify the best soil profi le location within each probe: 1) Review all three sides, if possible. 2) Compare each sidewall: Look for similar features Confi rm questionable conditions Contrast individual soil horizon depths 3) Select the shallowest depth to the limiting zone, and prepare the soil profi le description of that area. MEETING THE CERTIFICATION, TRAINING, AND RESOURCE NEEDS OF PENNSYLVANIA S SEWAGE ENFORCEMENT OFFICERS

7 Examining the Soil Test Probe TOOLS FOR THE FIELD Several tools are commonly used by the SEO to facilitate the evaluation of soil conditions within a soil test probe. These tools improve the ability to identify and describe soil limiting conditions. For instance, all SEOs use some type of probing device to expose natural soil surfaces within the probe. Common types of probing devices include the following: Rock hammer Brick hammer Dull knife Screwdriver Sharpshooter (long) shovel or spade MEETING THE CERTIFICATION, TRAINING, AND RESOURCE NEEDS OF PENNSYLVANIA S SEWAGE ENFORCEMENT OFFICERS

8 Examining the Soil Test Probe TOOLS FOR THE FIELD (continued) The following are some other items that might be useful to the SEO in the fi eld: Slope-measuring devices Munsell Soil Color Book Tape measures Clipboard Field sheets Writing utensils SEO Field Manual Spray bottle Compass or GPS unit Soil survey MEETING THE CERTIFICATION, TRAINING, AND RESOURCE NEEDS OF PENNSYLVANIA S SEWAGE ENFORCEMENT OFFICERS

9 The Soil Profile Description The soil profi le description is a characterization of the actual soil conditions within a test probe. Individual layers of soil, or horizons, are described using standard terminology. The purpose of a soil profi le description is to provide documentation and support of any soil limiting conditions noted during the review of a soil test probe. The following characteristics should always be included in a complete soil profi le description: Color Texture Structure Redoximorphic features (mottles) Consistence Rock fragment content Go to Chapter 6 Workbook to complete the following exercise: EXERCISE 6-1: Soil Profile Description Review MEETING THE CERTIFICATION, TRAINING, AND RESOURCE NEEDS OF PENNSYLVANIA S SEWAGE ENFORCEMENT OFFICERS

10 The Soil Profile Description THE LIMITING ZONE If a limiting condition is present, it should be clearly identifi ed and supported by the soil profi le description. The defi nitions in Title 25, Chapter 71, characterize a limiting zone: A soil horizon or condition in the soil profi le or underlying strata which includes one of the following: (i) A seasonal high water table, whether perched or regional, determined by direct observation of the water table or indicated by soil mottling. (ii) A rock with open joints, fracture or solution channels, or masses of loose rock fragments, including gravel, with insuffi cient fi ne soil to fi ll the voids between the fragments. (iii) A rock formation, other stratum or soil condition which is so slowly permeable that it effectively limits downward passage of effl uent. The limiting zone depth is perhaps the most important site evaluation feature described by the SEO. Minimum suitable soil depth requirements correspond to the type of onlot system absorption area that may be permitted. Go to Chapter 6 Workbook to complete the following exercise: EXERCISE 6-2: Limiting Zone Review MEETING THE CERTIFICATION, TRAINING, AND RESOURCE NEEDS OF PENNSYLVANIA S SEWAGE ENFORCEMENT OFFICERS

11 KEY POINTS: Safety is always a priority when evaluating a soil test probe. The entire soil test probe should be explored before writing the profi le description. The soil conditions should be carefully described to refl ect the most limiting condition noted within the probe. The SEO should use standard terminology to accurately characterize the soil features. Go to the #611 Chapter 6 materials to print and complete the Chapter 6 Quiz. This quiz was designed to check your understanding of the chapter materials. MEETING THE CERTIFICATION, TRAINING, AND RESOURCE NEEDS OF PENNSYLVANIA S SEWAGE ENFORCEMENT OFFICERS