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HomeMy WebLinkAboutMANOR Lots 1-6 Plat# 83-451 S-7041 MUNICIPALITY OF ANCHORAGE Department of Health & Environmental Protection Environmental Health Division Case Review Worksheet /0" ~1~ Case Number [ S-7041 REVISED Date Received May 17, 1983 Subdivision or Project Title: Comments Due By May 20, 1983 1 - 6 Manor Subdivisio (~ Public water available ublic sew ( ) Community water available Comments: · MANOR SUBDIVISION S &S ENGINEERS S & ENGINEERS, INC. $ 7125 OLD SEWARD HIGHWAY ° ANCHORAGE, ALASKA 99502 April 19, 1983 Chairman, Platting Board Municipality of Anchorage 632 W. 6th Ave. Anchorage, Alaska 99501 RE: Application for Approval - S & S Job No. 3151 Manor Subdivision Gentlemen: On behalf of our client BVD Investments, Inc., S & S Engineers, Inco is pleased to submit our request for approval of a residential cluster development. The project encompasses an 8.5 acre site located adjacent to Inspiration Drive, on the Eagle River Hillside. We feel that the cluster development, and our proposal in particular is appropriate for the site. The existing topography on this site somewhat constrains developement on this land. In addition, the developer wishes to incorporate usuable open space, and retain some common areas with natural vegetation. This cluster development provides a community water distribution system and all utility services, except sewage° A proposed land use plan has delineated open space in addition to the six residential lots. We feel this project is appropriate for this site and in keeping with the community's developing character° We ask for your support° WCH:dd Sincerely, ~illiam ¢. Hagmaier ANCHORAGE EAGLE RIVER WASILLA HOMER (907) 349-6561 (907) 694-9846 (907) 376-3770 (907) 235-8179 MANOR SUBDIVISION CLUSTER DEVELOPMENT A. SITE DESCRIPTION This site is located in the Hillside area of Eagle River. This project encompasses 8.5 acres on the south side of the mountain approximately 200 feet south of Jamie Driw~. The site topography is generally characterized by a moderate gradient to the southwest. The east and southeast portion of this property is characterized by a steep gradient of approximately 25 to 30% toward Meadow Creek, located approximately 300 feet southeast of this subdivision. A predominant knoll is located in the mid-central portion of this project. Slopes on the individual lots vary from 8% to as much as 25% in some locations. Vegetation on this project consists primarily of birch trees with some some small stands of black and white spruce. The western portion of this subdivision has only moderate vegetation, while the eastern portion of the subdivision generally has a more dense growth of vegetation and thicket. The property is zoned R-6, as is all the surrounding property adjacent to this subdivision. Access to and from the property is excellent and will be via Inspiration Drive to Jamie Drive. The property is owned and will be developed by BVD Investments of Anchorage. B. PLANNING OBJECTIVES: The petition area is currently zoned R-6, suburban residential district (large lot). The R-6 district is designed to encourage residential development, while at the same time preserving and enhancing those physical and environmental features which add to the desirability of' suburban living. As the site is presently zoned, the minimum lot size is 1 1/4 acres. The primary planning objective of the proposed cluster development is to provide single-family residential dwelling units with minimum environmental disturbance, while at the same time enhancing the rural character of the development. Page 2 S & S Engineers, Inc. Mt. Manor; Job 3151 April 19, 1983 Thus, we have set our planning objectives as follows: A. Retain a significant portion of the site in its natural state. B. Provide quality housing to the public at the most affordable cost. C. Lower the density to minimize aesthetic and environmental disturbance to adjacent areas. These objectives are difficult to meet under the current R-6 zoning. Approximately 1/3 of this subdivision is considered unusable for purposes of septic systems, because of the topographic constraints. The developer has proposed to install a community water system to serve this subdivision in order to minimize these topographic constraints on the septic systems. The economics of constructing a community water distribution network and corresponding pump house has dictated the design that has been submitted. The plan for this subdivision has taken into account all technical, economic, and aesthetic considerations as listed above in our planning objectives. The optimum design of this property is a cluster community of open space and residential homes with a community water and on-site septic system. This property currently has a maximum density of 8 units. The petitioner's request for this subdivision is for 6 units with an overall density of .7 dwelling units per acre which we feel will meet the planning objectives we have outlined above. C. PROJECT DESCRIPTION: The project will consist of 6 single-family dwellings with an average lot size of 140,000 sq. ft~J Each home will have its own private yard and access to ~h~ open space area. The existing set back requirements for the R-6 zone will be maintained. The open space provisions of this cluster development will be located at the east and southeast side of the subdivision and will be retained in their natural, undisturbed state. Page 3 $ & S Engineers, Inc. Mt. Manor; Job 3151 April 19, 1983 The construction of individual residences will be governed by the architectural control con~ittee and by the covenants, conditions, and restrictions for Manor Cluster Subdivision. D. OPEN SPACE: The tract of land currently proposed for development lies in a relatively undisturbed and natural state. The natural vegetation on the site consists of two major plant associations: mixed white spruce/deciduous forests and scattered birch and alders. It is the petitioner's intent to leave the land in its natural state as much as possible, preserving the natural vegetation. Only the locations for the proposed roads and residential homesites will be disturbed; the remainder of the site will be left in its natural state. Incorporated within the covenants will be provisions to restrict the amount of land that can be cleared for home construction. There will be two types of open space provided in Manor Subdivision: The first type will be held in private ownership by the owners of Lots 1 - 6. The private open space will be approximately 35,000 sq. ft. per lot which excludes the main structure, driveways, and parking aprons. The second type of open space is the undisturbed native vegetation, which will be held in common by the homeowners association. This open space is intended to preserve the natural surroundings, and serve as an additional buffer to Meadow Creek, which is located approximately 300 feet east of this subdivision. The total acreage of the undisturbed open space will be approximately 2.5 acres. Page 4 S & S Engineers, Inc. Mt. Manor Subdivision; Job 3151 April 19, 1983 E. PUBLIC UTILITIES: Ail utilities for this cluster development will be installed by the developer (with the exception of on-site septic systems). The water sYstem serving this subdivision will be a community system consisting of one well, a pump house, and a distribution system. This water system will meet both Municipal and State D.E.C. requirements. The existing well is more than adequate to provide service to the six lots. The existing well is currently rated at 20 gallons per minute, and full development of the well's potential is expected to raise the production level to as much as 30 to 35 gallons per minute. The State D.E.C. requirement for 20-minute sustained instantaneous demand flow for the total subdivision is a total of 16.2 gallons per minute. This requirement can be adequately handled by the existing well. The well, pump house, and distribution system will be conveyed to the homeowners association for the responsibility of maintaining the con%munity water system. Electrical service to this subdivision will be provided by M.E.A.; gas service by Enstar Gas; and telephone service by M.T.A. F. WASTEWATER DISPOSAL SYSTEMS: The soils present on this site are quite adequate for on-site disposal of wastewater. The surficial material throughout the site is a sandy silt with some organics. The surface layer varies in depths, from as little as two feet to as much as six to seven feet. Underlying this silty material is a slightly silty sand to coarse gravelly sand. The percability of these sands varies from 5 minutes per inch to 30 minutes per inch. These perc rates are well within the range of the requirements of the Dept. of Health and Environmental Protection. A minimum area of 10,000 sq. ft. with less than 20% grade has been provided on all lots for the placement of the waste disposal systems. No bedrock or water was encountered on this site. Page 6 S & S Engineers, Inc. Mt. Manor Subdivision; Job 3151 April 19, 1983 J. DEVELOPMENT SCHEDULE: It is the petitioner's intent to complete the development of the roads, water system and other utilities during the 1983 construction season. Construction of the road, water system, and other utilities will conform to the Municipal and State required standards. A subdivision agreement will be signed to insure the completion of these improvements. Development and construction on the individual lots will be by the individual lot owners and is estimated to occur over the next two years. // HARDING--LAWSON ASSOCIATES i21 W,t( f~re',vcecl Lane. Anchor,~e. Alaska 99503 · (907) 279-?011 April 2, 1976 5552,002.08 ;~2nginccrs, GcologLsts and Gcephys~c~te ~^¥ ~. u~t~,~; Unwin, Scheben & Korynta 103 E. 26th Avenue Anchorage, Alaska 99503 Attention: Mr. Earl Korynta, P.E. Gentlemen Soils Investigation Mountain Manor Subdivision Eagle River, Alaska This report presents the results of the soil investigation we performed for the proposed Mountain Manor Subdivision. Mountain Manor Subdivision consists of 61 acres located immediately south of Jamie Drive, about two miles east of the Eagle River business district. During our work we have consulted with Mr. Earl Korynta. The object of our investigation was to provide soils data for establishing the feasibility of disposal of sanitary wastes using seepage pits. Specifically our scope of work as outlined in our confirming proposal dated March 1, 1976, was to explore the soil conditions at the site by logging and sampling test borings, to perform laboratory tests on representative ~amples, and to provide a written- report describing the soil and ground water conditions. We also performed preliminary percolation tests to evaluate possible variations in percolation rates at the site. FIELD AND LABORATORY To investigate the soil conditions we drilled 27 borings during the period of February 27 through March 8, 1976. The borings were drilled using a six inch diameter flight auger to deoths varying from five to 15 feet. During the drilling our engineer was pres.ent to log the materials encountered and obtain grab samples of the soil types encountered. The locations of the borings are indicated on the Boring Location Plan, Plate 1, and the logs of the borings are presented on Plates 2 through 15. The soils have been classifie( in accordance with the Unified Soil Classification System described on Plate 16. Unwon, Schcben & Korynta ~5'52 ,002 .9~ A~r~ 1 2, in addition to the soil samplinq, percolation tests were performed in four of the borings. The percolation tests were performed in accordance with the procedure outlined in the USPIlS t~anual of Septic-Tank Practice with water surface levelsl six to ten feet below ground surface. After completion of the field work the samples were reexamined in our laboratory to select representative samples for testing. The laboratory testing consisted of particle size analysis to confirm ti~e soil classification. The results of the particle size analysis are presented on Plates 16 through 25, and are summarized on the boring loqso SITE AND SOIL CONDITIONS The site is a rectangle with dimensions of about 1300 by 2500 feet. Other than Jamie Drive which crosses the north edge of the property the site is undeveloped. Elevations vary from about 1100 feet above sea level in the northeast portion of the property to about 800 feet at the southeast corner. Most of the property has moderate slopes; of the total only about 10 acres have slopes in excess of 25 percent. Details of the topography and proposed development are shown on Plate 1. The site is primarily underlain by granular soils with varying amounts of silt fines to the depths exolored. The surface of the site is blanketed by forest duff (humus, leaves), and in a few locations is underlain by sandy and gravelly silt. Except for Boring! 2-4 and 3-9 where the silt is eight-feet-deep, the surface silt is generally less than five feet deep. The granular soils that generall] underlie the forest duff and also underlie the silt, vary in class- ification from slightly silty sand and gravel to silty sand and gravel. No free water was encountered in the borings. To assist in the evaluation of the site we have zoned the property into three typical soil types which should have somewhat similar percolation characteristics. The soil zones are shown on Plate 1 along with the description of the soil types for each zone. CONCLUSIONS Based on the results of the field and laboratory work, we be- lieve that seepage pits are a feasible method of septic tank effluent disposal. The preliminary percolation tests indicate a wide varia- tion in percolation rates (from less than one inch per minute to more than 30 minutes per inch). To optimize the design of the.seepag pits we believe that percolation tests should be oerformed on each lot after the road'.~ have been graded and site access developed. Wa trust ti]is provides ti~e information you require. If you have any questions please call. Very truly yours, IIARDING-LAWSON ASSOCIATES Duane L. Hiller Civil EnGineer - 3696-E / ~ Ja? M. England Civil Engineer - 1943-E DIAM: cs Attachments: Borino Location Plan I,ogs of Borings Soil Classification Chart & Key to Test Data Particle Size Analysis Copies: 5 Laboralory Tests Sieve Analysis 1% gravel 71% sand 28% silt LOG OF ,.30;~i~c, 3-5 Equipment 6" Fliqth n. user Elevation 1079 Date 2-27-76 6" Forest Duff 18" Seasonal Frost BROWN SILTY SA?iD' dense, moist (st4) BROWN SILTY SA:~DY GRAVEL (GM) dense, moist Sieve Analysis 43% gravel 40% sand 17% silt 10, 15 5 10 15 No free water encountered Equipment Elevation L O G O F BORING 3-6 995 Dele 3-2-76 3" Forest Duff 9" Seasonal Frost BROWN SANDY SILT (ML) medium stif, wet BROWN SILTY SANDY GRAVEL dense, moist '-Refusal @5' No free water encountered G:.t) HARDING - LAWSON ASSOCIATES ConsNIting E~,ghlccrs a~d Gcologists LOG OFBORING 3-6 & 3-5 MOUNTAIN MANOR Eagle River, Alaska PLATi ,JobNo. 5552,002.08 Appr: Date 3-18-76 '.- LOG OF ,']o~l;[:~c, 3-7 10 Equipment 6" Flight Augar Elevatlon 993 Date 3-2-76 12" Forest Duff 15" Seasonal Frost BROWN SILT ('4L) medium stiff, wet BROWN SILTY 'SANDY GRAVEL/' dense, moist No free water encountered 10 LOG OF B©RING 3-8 Equipment 6" F1 ight' A~gpr Elevation 979 Date 3-1-76 6" Forest Duff BROWN SILTY GRAVELLY SAND (S~,l) dense, moist BROWN SILTY SANDY GRAVE~ (G~)~'\! 15 No free water encountered LOG OF BORI;','C,S 3-7&3-8 r. IOUNTAIN MANOR Eagle River, Alaska PLAT~. Laboralory Tests LOG OF ~,3;',1XG 3-9 Equipment~ ,, ~j.;LghL..Aug er Elevation 932 Date 3-4-?6 6" Forest Duff GRAY GRAVELLY SILT (ML) medium stiff, wet Sieve Analysis 30% gravel 62% sand 8% silt 6.6 10' 15 GRAY GRAVELLY SATED d'en~e, wet ,,"%~. / ,. ~ ;,'~') SP-SFI) No free water encountered 10 15 L O G O F BORING 3-10 Equipmen l'j~, FLighj ~u ,~o~-- Elevation 931 Da're 3-4 -76 3" Forest Duff BROWN SILTY SANDY GRAVEL (GM) dense, moist BROWN SILTY GRAVELLY SAND (S>i) dense, moist No free water encountered LOG OF BORINGS 3-9&3-10 F%OUNTA IN MANOR EAGLE RIVER, ALASKA Test Hole ~5 Table A WO ~17585 pe~pth ir] Feet From To 0.0' 2.0 2.0' 2.5 3.5' 12.0 12.0 17.0 17.0' 20.0' Bottom of 'Pest Hole: 20.0 FT. Frost Line: 2.0 FT. Free Water Level: None observed Soil Description F-4, brown Gravelly Sandz Silt, ML, damp road edge waste, stiff, NP F-4 brown Sandy Silt,, MI,, damp, stiff, NP F-2, brown Silty Sa~,d, SM, damp, medium density, ap~roxim~-te'sil:t content 25% at 5' and 35% at 10' F-2, brown Silty Gravelly San~, SM, approxi- mate silt c~%te~t-[5%'[ d--~m[~ ~?edium density maximtun subrounded particle size F-l, brown very Sandy Silty Grave~, GM, d~mp medium density, approximate silt c~ntent' 30% maximum, particle size 3" ~NGINEERING & DEVELOPMEN'I- Box 90, Davis' SI., Eagle River, Alaska 99577 694-2774 or 688-2280 CO. Russell Oyster 694-2774 Performed for: Legal Description: SOIL LOG :4¢- Mailing Address; Earl Ellis 688-2280 T'H ~'/ Depth (feet) Soil Characlerlstlcs 0 1__ 2 3__ 4__ 5__ 6__ 7__ 8__ 9__ 10__ 11__. PLOT PLAN 12__ 13 14__ 15 Ground Water Encountered: Yes Proposed InstaLlation: Seepage Pit Comments: No ~ If yes, what depth Drain Field Performed by: PERC. TE~T 1 ~ ~IUp~~v' ~ c~ S S ENGINEERS, INC. CHORAGE ALASK'X 9~0..? 349 - 6 SLOP[ SITE PLAN 0'~ 1,2,5' ORC,-ANIC 5' P'-1.2.O ' ra-RA'f &RAV~U..Y' 5ANp w/TR~Cc S..~, ~. CoA'~SE$, /~/u~ERoo~ co~Bc~.s 0~CA~;SIOA)A~. BOUC, DE~.~ ~ ENCOUNTERED) 0 P IF YES. AT WHAT ~ __ , Oros$ Net Oeplh to Nel Reading Oa[e Time Time Water Drop 17 18 1834-E 19 20 PqOFESSIO~ PERCOLATION RATE TEST RUN BETWEEN COMMENTS -- S 7~25 OLD SEWARD HWY. '~ ....... "' & ENGiNEERs, INC. ANCHORAGE, ALASKA 9SNff~IPALITY OF ANCHORAGE  D~EPT. OF HEALTH :8~ ~ vi H( ( I A II(]N ' , S 549 - 6561 ENVIRCNMENTAL PROT¢CTIO~ ,";('ILS t. OG I%RC()I_AI'I(~N I e.s f~,lJCJ 'i 8 1983 ,..,,,.,,.,.,,,,,, LOP~I W~AI~ ~R .; : ..... SLOP( SITE PLAN ,o G,,.P N c ' " IF YES, AT WHAT DEPTH~ 20 .... * (minule$/inch) COMMENTS ~66 ~ &£NGINEERs.IH(:;. ANCHORAGE. ALASKA 99,5 dEPT. OF HEALTH S ~ : 349 - 656J ENVIRONMENTAL PRO'FECTIOF~ ,q lU;( L^IION AUG I 8 WAS GROUND WAFER ENCOUNTEREO~ IF YES. AT WHAT 3 4 5 9 10 12 15 S L 16 18 % JOt',N F. SWANSON? 2O COMMENTS PflOFESS~O~ PERCOLATION RATE -- TEST RUN BETWEEN ~ FT ANO 2 __ F1 ENGINEERS, INC. SOILS LOG 7125 OLD SEWARD HWY, ANCHORAGE, ALASKAML~{~)~'0L~TY oF ANCHORAGE DEPT, OF HfiA~TH & 349 - 6561 ~NV~RONM~NTA~ PROTECTION AU~1 g I~83 PERC()I. ATI()N FESI RECEIVED 9 10 tl 12 1 :l WAS GROUND WATER ENCOUNTER ED;' IF YES, AT WHAT DEPTH> Reading Oate ,AdO PERCOLATION RATE TEST tlUN BETWEEN F T AND COMMENTS & ENGINEERS, INC. s 3 4 9~ I0 I1 12 14 15 16 18 19 ~0 --71E5 OLD SEWARD HWY. ANCHORAGE, ALASKA ~I(~:I~ALITY OF ANCHORAGE DEPT. OF H~ALTi'i 349 - 6561 ENVIRONMENTAL PROTECTION~ ~'( tIC( I ATI()N ~, ,p S(~ILS I_OG PERC(~I_A'rI()N I'ESl ~A~o~ 5oB~/~ ~4No~ ~uBD OC2,o' o/~A~lo ~'~-T w/ WAS GROUND WATER ENCOUNTER EO) t~0 GrOS~ Net Depth to Net Read~n9 Dale Time Time Water Drop ';' ]0iK,I E. SW,9'. ~0N ~' o lB34-1! 0, PERCOLATION RATE .~L~.) /ct ~.~ Iminu~e,/inch) COMMENTS ENGINEERS, INC. I 3 4 .5 G ? 8 g 10 12 IG I? 2O 7125 OLD SEWARD-H'wY. ANCHORAGE, ALASKA 99,503 MUNICIPALITY OF ANCHORAOE DEPi' OF H~ALTI~& I'hlJC(II. AII()N ,549 - 6561 EINVir, ONM[N[AL PR~C[I~s~ S(ilLS L()G PERCOLATI()N rEsl AUU 'i :~ i~,f.~TH .~ ·/-/A6ff"/A I,.~ F~ /: . / / WAS GROUNO WATER -. ENCOUNTERED) IF YES, AT WHAT OEPTH) Reading Date Time COMMENTS