March 14, Mr. Bill Vetos 5473 Secrest Court Golden, Colorado 80403

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1 March 14, 2016 Mr. Bill Vetos 5473 Secrest Court Golden, Colorado Re: Percolation Test and Engineered Septic System Design OnSite Wastewater Treatment System (OWTS) Lot 2A, Vetos Vistas Filing 2 (A Resubdivision of Lot 1, Vetos Vistas) 5473 Secrest Court, Jefferson County (Golden), Colorado Soilogic Project # Mr. Vetos: Soilogic, Inc. (Soilogic) personnel have completed the test pit observation and site evaluation you requested to determine the suitability of the above referenced lot to support an OnSite Wastewater Treatment System (OWTS). We understand the system will treat effluent generated by your proposed singlefamily residence to be constructed on Lot 2A in the Vetos Vistas Filing 2 development in unincorporated Jefferson County, near Golden, Colorado. Results of the completed site evaluation and percolation test are included with this report. On February 21, 2016, Soilogic personnel completed drilling of the percolation test holes at the above referenced site near Golden, Colorado. The proposed location of the OWTS was premarked in the field by a representative of the client. At the time of our site exploration the ground surface in the percolation test area was observed to be moderately vegetated with an approximate twentypercent slope downward to the east. Evidence of prior building construction was not observed in the proposed Soil Treatment Area (STA) at that time. In addition, unsuitable, disturbed and/or compacted soils were not observed in the percolation test area. A 100foot Clear Creek Canal right of way is located along the eastern property line. No known easements exist within the area of the proposed septic system. To complete the percolation test, three (3) eightinch diameter and 36inch deep percolation test holes were completed in the area of the proposed Soil Treatment Area (STA). In addition, as part of our site evaluation, Soilogic personnel observed one (1) test pit excavation completed by others in the area of the proposed STA. The soils Soilogic, Inc th Avenue, Suite 200 Greeley, CO (970) P.O. Box 1121 Hayden, CO (970)

2 Percolation Test and Engineered Septic System Design OnSite Wastewater Treatment System (OWTS) Lot 2A, Vetos Vistas Filing 2 (A Resubdivision of Lot 1, Vetos Vistas) 5473 Secrest Court, Jefferson County (Golden), Colorado Soilogic Project # observed in the test pit excavation were classified in accordance with CDPHE WQCC Regulation 43, Table 10.1 and can be summarized as follows. Approximately 6 to 12 inches of topsoil and vegetation was observed at the surface at the test pit location underlain by light brown Clay Loam with a Blocky soil structure shape and a Moderate soil structure grade (Soil Type 3) which extended to a depth of approximately 4½ feet below present site grade and was underlain by beige/olivebrown Clay with No structure shape and a Weak structure grade (Soil Type 4A). The beige/olivebrown Clay extended to the bottom of the test pit excavation at a depth of approximately 6 feet below present site grade. A sample of Clay Loam was obtained from the test pit at a depth of approximately 4 feet below ground surface and a sample of Clay was obtained from the test pit at a depth of approximately 5 feet below ground surface for further evaluation. A graphic log of the test pit excavation is included with this report as test pit TP1. A diagram indicating the approximate test pit location is also included. Groundwater was not observed in the completed profile test pit to the depth explored at the time of our site visit. We expect periodically saturated soils do not exist within the top 6feet of subgrade soils in the area of the test pit excavation. An average percolation rate of 45 minutes per inch was established in the percolation test borings after presoaking for approximately 24 hours. Jefferson County guidelines require a percolation rate in the range of 5 to 60 minutes per inch for use of a nonengineered conventional OWTS. The measured percolation rate meets that criterion. In addition, Jefferson County guidelines require that neither groundwater nor bedrock be encountered within 6 feet of the ground surface in the proposed STA for use of a nonengineered conventional OWTS. The materials observed in the test pit examination indicate the thickness of the near surface site soils is sufficient and meets the groundwater and bedrock separation criteria. As part of our soil evaluation, hydrometer (ASTM D42263) tests was completed on representative portions of the minus #10 (2 mm) fraction of the soil samples obtained to determine the percent sand, silt and claysized particles in the samples. A summary outlining results of the completed hydrometer test is included with this report. Approximately 17 to 25% of the soil sample was retained on the #10 (2 mm) size sieve precluding the need for soil replacement procedures. According to Table 10.1 of the

3 Percolation Test and Engineered Septic System Design OnSite Wastewater Treatment System (OWTS) Lot 2A, Vetos Vistas Filing 2 (A Resubdivision of Lot 1, Vetos Vistas) 5473 Secrest Court, Jefferson County (Golden), Colorado Soilogic Project # CDPHE WQCC Regulation 43, the overburden soils sampled at a depth of 4feet below grade can be classified as Soil Type 3 or 3A with a corresponding LongTerm Acceptance Rate (LTAR) value of 0.35 or 0.30 gpd/sf respectively and the soils sampled at a depth of 5feet below grade can be classified as Soil Type 4 or 4A with a corresponding LongTerm Acceptance Rate (LTAR) value of 0.20 or 0.15 gpd/sf respectively. Based on results of the completed percolation and laboratory tests, it is our opinion the field established percolation rate of 45 minutes per inch, Soil Type 3 classification and corresponding LTAR of 0.35 gpd/sf could be used in design provided some mounding of the STA is completed. In our opinion, the Clay soil observed in the test pit excavation at a depth of approximately 4½ feet below present site grade would be considered a limiting layer. Due to the relatively close proximity of this limiting layer to the ground surface an engineered septic system will be required for this project. In order to develop the required 4feet of separation between the Clay limiting layer and the infiltrative surface of the STA, it is our opinion, the infiltrative surface could be established at a depth of approximately 6inches below existing site grade at the location of test pit TP1 and some mounding completed to develop finish grades in the STA. We expect the existing overburden Clay Loam will support proper treatment of septic effluent at an estimated percolation rate in the range of 4160 minutes per inch (Soil Type 3). The proposed infiltrative surface level is indicated on the attached boring log and site plan. The infiltrative surface should not be established any deeper than 6inches below ground surface at the location of boring TP1. In accordance with Jefferson County Health Department design criteria and using a design percolation rate of 45 minutes per inch (Soil Type 3) and corresponding Long Term Acceptance Rate (LTAR) value of 0.35 gpd/sf, a four (4) bedroom home utilizing a pump dosed chamber system in a bed configuration would require a minimum STA of 1155 square feet. Utilizing an equivalent footprint area value of 12 square feet per standard Quick4 Infiltrator unit, a 1155 square foot bed would require 97 Quick4 standard Infiltrator units in a singlebed configuration with a minimum septic tank capacity of 1,250 gallons. A proposed system layout including one (1) bed with four (4)

4 Percolation Test and Engineered Septic System Design OnSite Wastewater Treatment System (OWTS) Lot 2A, Vetos Vistas Filing 2 (A Resubdivision of Lot 1, Vetos Vistas) 5473 Secrest Court, Jefferson County (Golden), Colorado Soilogic Project # rows of 25 units for a total of 100 units is included with this report. A site evaluation and design calculation summary is also included. In general, we recommend the near surface site soils be excavated to a maximum depth of 6inches below ground surface at the location of the proposed STA. Due to the moderately steep cross slope of the ground surface in the area of the proposed STA, the majority of the infiltrative surface will need to be established on fill material (See Section Detail). After stripping any bulk vegetation and benching the excavation we recommend concrete sand (ASTM C33) be placed in loose lifts not to exceed 9 inches thick, adjusted to within ±3% of standard Proctor optimum moisture content and compacted to within 8085% of the materials standard Proctor maximum dry density in the area that backfill soils are needed to establish the STA s infiltrative surface. Scarification and compaction of leveled subgrade soils in the STA should not be completed. In addition, we recommend excavation be completed remotely and construction equipment and vehicles not allowed to operate in the STA. As a precaution, we recommend a minimum 30mil PVC liner be installed on the downhill side of the STA extending from one (1) foot above the infiltrative surface to a minimum depth of one (1) foot below existing ground surface in order to reduce the potential for the lateral transmission of effluent. A minimum of 12 inches of mounding soil cover will be required overlying the Infiltrator units. This will result in a mound surface approximately 18inches above existing site grade on the uphill side of the STA and approximately 48inches above existing site grade on the downhill side of the STA. The mound taper should be constructed with slopes no greater than two (2) feet horizontal to one (1) foot vertical (2:1). After stripping and prior to placement of any fill in mound taper areas, we recommend the exposed site soils be scarified to a depth of 9inches adjusted and compacted to at least 95% of the materials standard Proctor maximum dry density. The moisture content of the scarified site soils should be adjusted to within the range of ±2% of standard Proctor optimum moisture content at the time of compaction. We recommend the taper fill materials be placed in loose lifts not to exceed 9 inches thick, adjusted to within ±2% of standard Proctor optimum moisture content and compacted to at least 95% of the materials standard Proctor maximum dry density. Based on the materials encountered in the completed test pit excavation and results of laboratory

5 Percolation Test and Engineered Septic System Design OnSite Wastewater Treatment System (OWTS) Lot 2A, Vetos Vistas Filing 2 (A Resubdivision of Lot 1, Vetos Vistas) 5473 Secrest Court, Jefferson County (Golden), Colorado Soilogic Project # testing, it is our opinion the site Clay Loam could be used to develop the mound and mound tapers. A septic system design detail is included with this report. We recommend the top of the septic tank be established a minimum of 12inches below finished site grade. We understand Jefferson County Health Department regulations require the top of the septic tank to be buried no deeper than 4feet below grade. Some septic tank manufacturers specify the top of the tank to be established no more than 2feet below grade. Care was taken to establish the percolation test area outside minimum required setback distances from site features. A minimum 25foot setback is required between the STA and potable water supply lines and a minimum 10foot setback is required between the STA and property lines. A minimum 50foot setback is required between the STA and ditches. According to the Colorado Division of Water Resources, no water wells are present within 100feet of the proposed STA. No setbacks other than those indicated on the attached diagrams are known to affect the proposed system. Care should be taken at the time of system installation to ensure Jefferson County requirements concerning minimum required separation distances between system components and site features and amenities are maintained. Offset distances are shown in their approximate location on the included percolation test location and proposed layout diagrams. The owner should realize an OWTS is different from public sewer service and assume the responsibility for maintenance of the OWTS. The system is relatively maintenance free although periodic pumping of the septic tank will be required. Water use must be monitored so toilets and other fixtures are not allowed to continuously run. A freely running toilet can consume in excess of 1,000 gallons per day. An excess 1,000 GPD can flood and irreparably harm the onsite septic system. In addition, toxic or chemically treated pool and or spa water and plastic and other nonbiodegradable materials should not be introduced into the OWTS. Sprinkler systems should not be installed or allowed to irrigate over the absorption bed area. In addition, livestock should not be allowed to graze over the absorption field and the field should not be subjected to vehicle traffic. We recommend the surface of the

6 Percolation Test and Engineered Septic System Design OnSite Wastewater Treatment System (OWTS) Lot 2A, Vetos Vistas Filing 2 (A Resubdivision of Lot 1, Vetos Vistas) 5473 Secrest Court, Jefferson County (Golden), Colorado Soilogic Project # absorption field area be seeded after installation using a dryland seed which does not require irrigation water. In addition, the absorption bed area should be mowed to maintain vegetation in the range of 6 to 12 inches in height. We appreciate the opportunity to be of service to you on this project. If you have any questions concerning the enclosed information or if we can be of further service to you in any way, please do not hesitate to contact us. Very Truly Yours, Soilogic, Inc. Reviewed by: Josh Schmidt Engineering Technician Wolf von Carlowitz, P.E. Principal Engineer

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8 LOT 2A, VETOS VISTAS FILING 2 (RESUBDIVISION OF LOT 1, VETOS VISTAS) 5473 SECREST COURT, JEFFERSON COUNTY, GOLDEN, COLORADO Project # LOG OF TEST PIT TP1 March 2016 Sheet 1/1 Drilling Rig: Unknown Water Depth Information Start Date Finish Date Surface Elev. Auger Type: Hammer Type: Field Personnel: JS During Excavtion After Excavtion 24 Hours After Excav. None None None USCS Estimated Swell % Passing SOIL DESCRIPTION Depth "N" MC DD q u % Pressure Atterberg Limits # 200 Sieve Sampler (ft) (%) (pcf) (psf) 500 psf (psf) LL PI (%) 612" VEGETATION & TOPSOIL 1 Proposed Infiltrative Surface Level (6" Below Exisitng Grade at Location of Test Pit TP1) USDA: CLAY LOAM 2 Soil Type 3, Blocky, Moderate light brown 3 4 USDA: CLAY 5 Soil Type 4A, Massive beige, olivebrown 6 BOTTOM OF TEST 6.0'

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11 LOT 2A, VETOS VISTAS FILING 2 (RESUBDIVISION OF LOT 1, VETOS VISTAS) 5473 SECREST COURT, JEFFERSON COUNTY, GOLDEN, COLORADO Project # ' March 2016 Gradation Analysis Test Summary (ASTM C 117 / C 136) Sieve Size #4 (4.75 mm) #10 (2.0 mm) #40 (0.425 mm) #200 (0.075 mm) % 'Rock' Greater than 2mm in Diameter Percent Passing (%) ~25% Percent Finer by Weight 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% (USDA) 100% Hydrometer Analysis of 2.0 mm Fraction (ASTM D 42263) #10 # mm % 0.05 mm 55% 52% 46% 45% 43% Grain Size in Millimeters % 33% mm Sand Silt Clay Soil Texture Triangle (USDA) Summary of Hydrometer Analysis (USDA) Grain Size Classification Fraction % Sand 40% Silt 25% Clay 35% USDA Soil Texture: CLAY LOAM

12 LOT 2A, VETOS VISTAS FILING 2 (RESUBDIVISION OF LOT 1, VETOS VISTAS) 5473 SECREST COURT, JEFFERSON COUNTY, GOLDEN, COLORADO Project # ' March 2016 Gradation Analysis Test Summary (ASTM C 117 / C 136) Sieve Size #4 (4.75 mm) #10 (2.0 mm) #40 (0.425 mm) #200 (0.075 mm) % 'Rock' Greater than 2mm in Diameter Percent Passing (%) ~17% Percent Finer by Weight 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% (USDA) 100% 94% Hydrometer Analysis of 2.0 mm Fraction (ASTM D 42263) #10 # mm mm Grain Size in Millimeters 74% 86% 84% 80% 68% 62% mm Sand Silt Clay 48% Soil Texture Triangle (USDA) Summary of Hydrometer Analysis (USDA) Grain Size Classification Fraction % Sand 8% Silt 39% Clay 53% USDA Soil Texture: CLAY

13 LOT 2A, VETOS VISTAS FILING 2 (RESUBDIVISION OF LOT 1, VETOS VISTAS) 5473 SECREST COURT, JEFFERSON COUNTY, GOLDEN, COLORADO Project # March 2016 SITE EVALUATION SUMMARY AND DESIGN CALCULATIONS ONSITE WASTEWATER TREATMENT SYSTEM (OWTS) Soilogic Field Personnel Information Wolf von Carlowitz, P.E th Avenue, Suite 200 Greeley, Colorado Wolf@Soilogic.com Date of Drilling Presoak and Percolation Test (2/12/2016 2/14/2016 2/15/2016) Septic System Design Calculations 4 Bedroom House, Q = 525 gpd Percolation Rate = 45 mpi and LTAR = 0.35 g/d/sf A = Q/LTAR = 525 / 0.35 = 1500 sf Size Adjustment Calculations and Infiltrator Calculations 1500 sf * 1.1 (Dosed) * 0.7 (Chambers) = 1155 sf 1155 sf / 12 sf per Quick4 Infiltrator Unit = 97 Units Soilogic proposes one (1) bed with four (4) rows of 25 units each for a total of 100 units Alternative configurations could be considered.