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Home My WebLink AboutZODIAK MANOR Lot 85 S82-3 Request for Well Regulation Wavier / I)E~. OF E~IRONME~ C~NSERVz~ON / 437 E Street, Suite 200 December 3, 1982 Ms. Linda Kross Grants Administrator Anchorage Water & Wastewater Utilities 3000 Arctic Boulevard Anchorage, Alaska 99503 D~PT, OF HF.~'I~I & 'JAN 9 6 1988 RE: Plans and Specifications Request of Well Regulation Waiver Zodiak LID No. 85, S82-3 RECEIVED Dear Ms. Kross: Thank you for the plans specificatons and engineer's report in request of a well regulation waiver for the referenced project under your letter of November 3, 1982. The construction of the referenced project will include the installation of 1,437 feet of 8 inch ductile iron pipe, 2 type "A" manholes, 3 type '%" special manholes, 1 special cleanout and other appurtenant items. The plans and specifications are approved for matters of concern to this Department. In accordance with Title 18 of the Alaska Administrative Code Chapter 72 (18 AAC 72.021.a), Mr. Carl Steeby, P.E., submitted a report for ADEC's review and consideration to waive estiablished separation distances to construct, maintain and operate portions of Zodiak LID No. 85 closer to drinking water sources. More particularly, construction of the referenced project will require a waiver to encroach upon the well radius of nine wells adjacent to this project. In recognition of the report, the plans and specifications for the proposed sewer line, the following separation distances are approved instead of that required in Table A of 18 AAC 72.021. Separation distances of 67 and 96 feet between a private well on Lot 9, Block 3, Zodiak Manor Alaska Subdivision and proposed sewer line and nearest manhole respectively. 2. Separation distance of 62 feet between a private well on Lot 10, Block 3, Zodiak Manor Alaska Subdivision and proposed sewer line. Ms. L. Kross S82-3 December 3, 1982 Page 2 3. Separation distance of 65 feet between a private well on Lot 11, Block 3, Zodiak Manor Alaska Subdivision and proposed sewer line. 4. Separation distances of 29 feet each between a private well on Lot Block 4, Zodiak Manor Alaska Subdivision and proposed sewer line and nearby cleanout respectively. 5. Separation distances of 45 and 64 feet between a private well on Lot 6, Block 4, Zodiak Manor Alaska Subdivison and proposed sewer line and nearby cleanout respectively· 6. Separation distances of 39 and 86 feet between a private well on Lot 7, Block 4, Zodiak Manor Alaska Subdivision and proposed sewer line and nearest manhole respectively. 7. Separation distances of 38 and 48 feet between a private well on Lot 8, Block 4, Zodiak ~qanor Alaska Subdivision and proposed sewer line and nearest manhole respectively. 8. Separation distances of 48 feet each between a private well on Lot 9, Block 4, Zodiak Manor Alaska Subdivision and proposed sewer line and nearest manhole respectively. 9. Separation distances of 49 and 76 feet between a private well on Lot 10, Block 4, Zodiak Flanor Alaska Subdivision and propsed sewer line and nearest manole respectively. In reference to the most critical cases, the oro×imity of the nearest manhole and private wells on Lot 8, Block 4 an'd Lot 9, Block 4, Zodiak Manor Alaska Subdivision causes this department some considerable concern. It seems possible that any exfiltration, no matter how unlikely it may seem, would fall within the radius of influence of the private wells. However, the department finds that the special manholes detailed in the plans and specifications as the most feasible solution to the separation distance problem. Within the special manholes, the sewer line's flanged pipe is mechanically sealed and gasketed to prevent leakage of any se~age into the manhole. ~ithout difficult implications for sewer line maintenance (not within the standard manhole description depicted in the State adopted Ten State Standards) and some knowledge of the geologic conditions, this department finds the above separation distances as adequate protection of the private water sources. It is understood that in the near future, public water will be extended into the affected area. Specifically ~hen is CONSULTING ENGINEERS INTERNATIONAl. ENGINEERING COMPANY, INC. 3904-060 Mr. Reford G. Reid Construction Grants Project Alaska Dept. of Environmental Conservation 437 "E" Street, Suite 200 Anchorage, Alaska 99501 Reference: Zodiak Manor LID #85 Dear Mr. Reid: DEPT. O~ H~ALTH & BI'~'IROhIMENTAL P~OTECTIQN JAN 6 19 . RECEIVED The Anchorage Water and Wastewater Uti. li.ty (A~qU) seeks ADEC approval to construct, maintain and operate a portion of the Zodiak Manor LID #85 closer to drinking water sources than established separation distances specified in State Drinking Water Regulations. In request of a regulation waiver and in accordance with Title 18 of the Alaska Administrative Code Chapter 80 (18 AAC 80.020.d), Anchorage ~ater and Wastewater Utility submits the following report for your review and consideration. The subject wells are located in the Zodiak Manor Alaska Subdivision in Anchorage, Alaska. A listing of well locations within a lO0-foot proximity of proposed manholes and cleanout is given in Table Z. A listing of well locations within a 75-'foot proximity of the proposed mainline sewer is given in Table 2. All wells are private systems serving individual dwell~gg units. Within the subject we'll radius "w~ivern area, the sewer pipe will be 8 inch Ductile Iron Pipe, Class 50. The subject pipe has a working pressure of 350 psi plus a surge allowance of 100 psi. This particular sewer trunk is a gravity system which will be 0.0 psi working pressure, making it ideal for construction within well radius. On a gravity system there is more static pressure on the outside of the pipe than on the inside, thus giving more concern to i. nfiltration than exfiltration. Ductile iron pipe has a life expectancy greater than other conduit materials because of its structrual stength, resistance to abuse, abrasive elements and corrosion. All manholes constructed within 100 feet of a private well will be specially censtructed to watertight standards using gasketed-mechanical joint pipe fittings through the manholes. A cleanout within 100 feet of a private well will be specifically constructed to watertight standards. Details of construction are described in the at~ached drawings and specifica- tions. A review of soils reports for this project area shows that soils along Solar Drive and Comet Court are generally dense, silty sandy gravels with lenses of gravelly sands. INTERNATIONAL ENGINEERING ~,~JMPANY. INC. Reford G. Reid October 28, 1982 Page 2 3904-060 Logs for seven (7) wells along Solar Drive and Comet Court show the following information. Lot 9, Block 3: 163' well, 162' cased Sands and gravels to silty gravel and clayey layer at 85'. Lot 11, Block 3: 159' well Silty sands and gravels with sandy gravel lense between 77' and 79' Lot 5, Block 4: 105' well, 103' cased Silty sands and gravels with sandy gravel lense between 54' and 65'. Lot 6, Block 4: 100' weli Silty sands and gravels with sand and gravel lenses between 42~ and 49' and between 85' and 89' Lot 8, Block 4: 110' well Silty sands and gravels. Lot 9, Block 4: 154' well, 151' cased Silty sands and gravels with sand lense between 161 and 22'; gravel lense'between 77' and 78~; and sand layer between 116~ and 140'. Lot 10, Block 4: 85~ well Sands and gravels to clay layer between 33' and 75'. The presence of silty and clayey strata provide an impermeable layer between the sewer pipe and the bottom of the wells. Sincerely, Carl Steeby~ P.E: ' Principal Civil Engineer Attachments: Plans & Specifications hdu7 Reford G. Reid Page 3 October 28, 1982 3904-060 TABLE Distances Between Existing Private Wells and Proposed Special Manholes and Cleanout (Within ].O0-foot proximity) Well Location Distance (Least) Special Structure Lot 9, Block 3 Lot 5, Block 4 Lot 6, Block 4 Lot 7, Block 4 Lot 8, Block 4 Lot 9, Block 4. Lot 10, Block 4 96 29 64 86 48 48 76 Manhole Cleanout Cleanout Manhole Manhole Manhole Manhole Reford G. Reid Page 4 October 28, 1982 3904-060 TABLE 2 Distance Between Existing Private Well~ and Proposed Mainline Sewers (within 75' proximity) Well Location Distance (Least) Lot 9, Block 3 67' Lot 10, Block 3 62' Lot 11, Block 3 65' Lot 5, Block 4 29' Lot 6, Block 4 45' Lot 7, Block 4 39' Lot 8, Block 4 38' Lot 9, Block 4 48' Lot 10, Block 4 49'