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HomeMy WebLinkAboutSeptic Response Letter - Correspondence - 130 REA STREET 11/18/2019 Benjamin C. Osgood, Jr., PE 157 Bluff Street Salem, NH 03079 November 18, 2019 Brian LaGrasse, CEHT Director of Public Health North Andover Health Department 120 Main Street North Andover, MA 01845 90'L�1g Re: 130 Rea Street NO Np� P. Response to Denial Letter#2 N Dear Brian, Enclosed is a revised plan and additional documents as detailed below to address the comments in your letter dated November 12, 2019. The responses to the deficiencies listed in numerical order are as follows. 1. Enclosed with this letter is the document with the variance explanations and support. 2. A variance request was included on the plan. The wording has been revised to more clearly state the fact that a passing percolation test was not obtained. 3. The variance stated on the plan was revised. 4. A variance for the reduced over dig has been added 5. The 99 contour was corrected to 98 6. The errant notations have been removed. 7. The soil stockpile has been relabeled as a topsoil stockpile. There is plenty of room to access this topsoil pile around the end of the system. Most excavators are no wider than 8', the system is located 11 feet from the property line, which leaves 3' of buffer to fit the excavator. 8. The 5' over dig is labeled to the right of the system as "LIMIT OF SAND(see note#3)". The reduced over dig location is required to avoid moving the gas line and is now labeled on the plan. 9. The secondary maintenance requirement is added to the plan. This is in addition to the certification from the owner which was already provided as previously requested. 10. The plan view detail shows the clean out location as being 2.5' from the edge of the leach field. This should be enough stone to prevent any scouring of the sand overdig. The clean out detail does not show the stone beyond the clean out for clarity. 11. The elbow has been noted in the detail as being a sweep elbow. 12. Generally, the building sewer is re-used on our designs. In this case the building sewer is located beneath the basement slab so would be very difficult and expensive to replace. A note has been added to cut back the building sewer to allow for the new tank location. 13. The form 12 is attached. 14. 1 have been told that the operation and maintenance contract is usually provided at the time of purchase. The owners are working to make the purchase but don't want to finalize the purchase and commit to a maintenance plan until the plan is approved. I will try to provide a proposed sample but the final document cannot be provided until the STU is purchased. 15. The standard septic tank location has been added. 16. The calculations have been revised to indicate the 0.15 GPSF loading rate and a variance for the size reduction has been added. If you have any questions or additional comments, please let me know. Sincerely, Benjamin C. Osgoo�, JrPE November 13, 2019 Memorandum in support of Title 5 Variances 130 Rea Street, North Andover, MA In association with the septic system design plans submitted for approval to the North Andover board of Health the following Title 5 Variances are requested. 1. Allow the location of a leach field in soils with a percolation rate greater than 90 min per inch (no percolation test obtained) in lieu of having a percolation test complying with Title 5 Section 15.245. 2. Allow the reduction in removal of required lateral distance of unsuitable material removal from 5' required by Title 5 Section 255 (5) to as little as 3' adjacent to the gas line. As part of the Title 5 approval process the person requesting a variance has to establish the following. a. Enforcement of the provision of 310 CMR 15.000 from which a variance is sought would be manifestly unjust, considering all the relevant facts and circumstances of the individual case. b. That a level of environmental protection that is at least equivalent to that provided under 310 CMR 15.000 can be achieved without strict application of the provision of 310 CMR 15.000 from which a variance is sought. In regards to strict enforcement being manifestly unjust, the property owner purchased the home in approximately 1964 when the home was newly constructed. As part of that construction a subsurface sewage disposal system was constructed under the then current regulations for subsurface systems, which was not as stringent as today's regulations. That system is the system that exists today as it has never required replacement. The home has been continually occupied by as many as 4 persons and the system has never experienced a failure where effluent backed into the home or was present on the ground surface. It would be manifestly unjust to decide now that a system could not be constructed in approximately the same area where the system has existed for 55 years without having a problem. In regards to providing the same level of environmental protection as strict conformance with Title 5, the following facts are presented. • Although the attempted percolation test was not successful, there was a drop in the level of water of Y4" in 1 hour, which indicates that there is some level of absorption by the soil in the area of the proposed system. • The USDA soil maps indicate that the classification of soils in this location are "Udorthents, Smoothed", which are defined as "excavated and filled land, loamy." This soil mapping also provides a capacity of the soil to transmit water which ranges between .06 and 20.0 inches per hour. • During the soil testing a sample of soil was taken and sent to the University of Massachusetts Soil Testing Lab to determine the soil texture. The results of that test indicate that the soil is a sandy loam. • A commonly used infiltration rate standard is the rates developed by Rawls, Brakensiak, and Saxton in 1982, commonly called the Rawls Rates. The ravels rate for a sandy loam soil is listed as 1.2 inches per hour, 0.52 inches per hour for loam, and 0.27 inches per hour for silt loam. • Using the most conservative rate listed in the soil survey of 0.06 inches per hour, the capacity of the soil under the proposed 2,200 square foot sand fill area to transmit effluent can be calculated and converted to gallons per day. The equation is as follows. o Transmissivity (in/hr) x Area (sq. inches) x 24 hours = cubic inches in 24 hours. • 0.06 in/hr. x 2,200 sq. ft. x 144 sq. in/sq. ft. x 24 hours = 456,192 cubic inches o Convert cubic inches to cubic feet and multiply x 7.5 gallons per cubic feet • 456,192/1728 x 7.5 = 1,980 gallons per day • This calculation has used the most conservative value for transmissivity of the underlying soil which demonstrates that even with a very low transmissivity the underlying soil has more than 4 times the daily capacity to absorb water than the daily flow calculated in the system design. Conclusion: The system will provide a level of environmental protection that is at least equivalent to that provided under 310 CMR 15.000 without strict application of the provision of 310 CMR 15.000 from which a variance is sought for the following reasons. 1. The effluent will be highly treated in the STU befor it is distributed to the leach field. 2. The leach field will provide additional treatment in the 2' of sand below the system which will be above the water table. 3. The soil below has the capacity to absorb the effluent from the dwelling as evidenced by the 50+ years of experience with the existing system, which is further enforced by the calculations of infiltrative capacity provided above. Soil Map—Essex County,Massachusetts,Northern Part (130 Rea Street,North Andover,Soil Map) �o 327550 3275W V7610 327640 327G70 7700 327M 3277W 3Ym 327820 3Z7850 42"49 3'N �y 42-40'3'N E t�, i rk m '" �aa j w4, hm Al In pea St Map mays tid 42°39 56'N 42'39 56'N 0 227550 327580 3Z7610 3Z7W 327670 327700 327730 327 0 32779D 32762t0 3ZM50 3 3 Map Scale:1:1,500 f printed on A landscape(11"x 8.5")sheet N Meters 0 20 40 80 120 /V 0 b0 100 200 300 Map prcjedon:Web Mercator Corner coordinates:WGS84 Edge tics:UrM Zone 19N WGS84 „. Natural Resources Web Soil Survey 11/14/2019 Conservation Service National Cooperative Soil Survey Page 1 of 3 Map Unit Description:Udorthents,smoothed—Essex County,Massachusetts,Northern Part 130 Rea Street,North Andover,Soil Map Essex County, Massachusetts, Northern Part 651—Udorthents, smoothed Map Unit Setting National map unit symbol: vjwk Elevation. 0 to 3,000 feet Mean annual precipitation: 45 to 54 inches Mean annual air temperature: 43 to 54 degrees F Frost-free period., 145 to 240 days Farmland classification: Not prime farmland Map Unit Composition Udorthents and similar soils: 80 percent Minor components: 20 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Udorthents Setting Parent material. Excavated and filled land loamy and/or excavated and filled land sandy and gravelly Typical profile H9 -0 to 6 inches: variable H2- 6 to 60 inches: variable Properties and qualities Slope: 0 to 3 percent Depth to restrictive feature: More than 80 inches Capacity of the most limiting layer to transmit water(Ksat): Moderately low to very high (0.06 to 20.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 6s Hydrologic Soil Group: A Hydric soil rating: Unranked Minor Components Urban land Percent of map unit. 10 percent Hydric soil rating: Unranked Beaches Percent of map unit 8 percent Hydric soil rating: Unranked tSi) Natural Resources Web Soil Survey 11/14/2019 Conservation Service National Cooperative Soil Survey Page 1 of 2 Soil Map—Essex County,Massachusetts,Northern Part (130 Rea Street,North Andover,Soil Map) MAP LEGEND MAP INFORMATION Area of Interest(AOI) Spoil Area The soil surreys that comprise your AOI were mapped at Area of Interest(AOI) 1:15,800. � Stony Spot Soils Very Stony Spot Warning:Soil Map may not be valid at this scale. Soil Map Unit Polygons Wet Spot Enlargement of maps beyond the scale of mapping can cause Soil Map Unit Lines misunderstanding of the detail of mapping and accuracy of soil Other line placement.The maps do not show the small areas of Soil Map Unit Points Special Line Features contrasting soils that could have been shown at a more detailed Special Point Features scale. `1 Blowout Water Features Streams and Canals Please rely on the bar scale on each map sheet for map Borrow Pit measurements. Transportation Clay Spot Source of Map: Natural Resources Conservation Service ++ Rails Closed Depression Web Soil Survey URL: Interstate Highways Coordinate System: Web Mercator(EPSG:3857) Gravel Pit US Routes Maps from the Web Soil Survey are based on the Web Mercator Gravelly Spot Major Roads projection,which preserves direction and shape but distorts distance and area.A projection that preserves area,such as the Landfill Local Roads Albers equal-area conic projection,should be used if more Lava Flow Background accurate calculations of distance or area are required. Marsh or swamp Aerial Photography This product is generated from the USDA-NRCS certified data as of the version date(s)listed below. + Mine or Quarry Soil Survey Area: Essex County,Massachusetts,Northern Part Miscellaneous Water Survey Area Data: Version 15,Sep 12,2019 Perennial Water Soil map units are labeled(as space allows)for map scales Rock Outcrop 1:50,000 or larger. J� Saline Spot Date(s)aerial images were photographed: Aug 29,2014—Sep 19,2014 Sandy Spot The orthophoto or other base map on which the soil lines were Severely Eroded Spot compiled and digitized probably differs from the background r. Sinkhole imagery displayed on these maps.As a result,some minor shifting of map unit boundaries may be evident. Slide or Slip Sodic Spot Natural Resources Web Soil Survey 11/14/2019 Conservation Service National Cooperative Soil Survey Page 2 of 3 Soil Map—Essex County,Massachusetts,Northern Part 130 Rea Street,North Andover,Soil Map Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 6A Scarboro mucky fine sandy 1.5 14.5% loam,0 to 3 percent slopes 260B Sudbury fine sandy loam,3 to 4.7 45.6% 8 percent slopes 420E Canton fine sandy loam,3 to 8 0.7 7.1% percent slopes 651 Udorthents,smoothed 1.8 17.4% 718A v Saco variant silt loam,0 to 3 1.6 _ 15.4% percent slopes Totals for Area of Interest 10.3 100.0% -- u Soil and Plant Nutrient Testing Laboratory UMass 161 Paige Laboratory 161 Holdsworth Way University of Massachusetts Extension Amherst,MA 01003 Phone: (413)545-2311 e-mail:soiltest@umass.edu website:soiltest.umass.edu Particle Size Analysis - Comprehensive with 2mm Passing Sample Information: Sample ID: 130RS Prepared For: Ben Osgood Order Number: 47176 157 Bluff St Lab Number: X190930-102 Salem,NH 03079 Received: 9/30/2019 Reported: 10/3/2019 bosgoodpe@gmail.com 978-435-1324 USDA Size Fraction Percent of Whole Sample Passing Whole Sample%of Finer Than 2mm%of Main Fractions 0.0 mm Percent SizeSieve# Sample Passing Sample Passing Sand 0.05-2,0 62.2 2.00 #10 74.4 100.0 Silt 0.002-0.05 31.5 1.00 #18 69.1 92.9 Clay <0.002 6.3 0.50 435 61.9 83.2 0.25 #60 51.8 69.7 Sand Fractions Size(MM) Percent 0.10 #140 39.0 52.4 Very Coarse 1.0-2.0 7.1 0.053 #270 28.1 37.8 Coarse 0.5-1.0 9.7 0.02 20 um 16.5 22.2 Medium 0.25-0.5 13.5 0.005 5 um 6.6 8.9 Fine 0.10-0.25 17.3 0.002 2 um 4.7 6.3 Very Fine 0.05-0.10 14.7 Silt Fractions Size mm Percent Coarse 0.02-0.05 15.6 Medium 0.005-0.02 13.3 Fine 0.002-0.005 2.6 USDA Textural Class: sandy loam Gravel Content: (%) 25.6 1 of 1 Sample ID: 130RS Lab Number X190930-102 Commonwealth of Massachusetts City/Town of North Andover Percolation Test Form 12 4 Percolation test results must be submitted with the Soil Suitability Assessment for On-site Sewage Disposal. DEP has provided this form for use by local Boards of Health. Other forms may be used, but the information must be substantially the same as that provided here. Before using this form, check with the local Board of Health to determine the form they use. Important:When filling out forms A. Site Information on the computer, Woodcock Family Realty Trust use only the tab Y Y _ key to move your Owner Name cursor-do not 130 Rea Street _ use the return ------- --- ----- — key. Street Address or Lot# North Andover MA 0 45 -- ---- - - r� City/Town State Zipp Code William P. Woodcock Contact Person(if different from Owner) Telephone Number - - B. Test Results 8-13-19 9:00 Date Time Date Time Observation Hole# PT 1 Depth of Perc 48"/14" Start Pre-Soak 8:52 End Pre-Soak 9:07 —Time at 12" 9:07 Time at 9" Time @ 11-3/4" 10:07 - — Time at 6" N/A Time (9"-6") N/A - -- — Rate (Min./inch) 1/4"11 Hr._ Test Passed: ❑ Test Passed: ❑ Test Failed: ® Test Failed: ❑ Benjamin C. Osgood, Test Performed By: Erin Kirchner Board of Health Witness Comments: t5form12.doc•08/15 Perc Test•Page 1 of 1