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HomeMy WebLinkAboutCertified Designer - SWG Letters / Memos - 2/23/1991 WA ki .� 4 119 ROBERT :SHIN Property Block 4 & 5 Allyn, WA General Description In order to establish proper setbacks and k,ross land Area, a study of the tide lines was made on Saturday, Feb. 23, 1991. The tide tables indicated a high tide of 10? feet at 10:27 A.M. The corrections for Allyn are (Time + 0:26 min. ) & (High water + 2.7 ft. ). Using these figures, a line at 10:33 A.M. would equal an 11.8 tide line and a reading (at_.10:53 A.M. ) would equal a 13.4 ft. line. Comparing these lines to the established approximate Hi-Water Line on the survey map increases the property depth considerably. The 13.4 tide line is approximately in the area of vegetation and appears to represent reasonable Mean-Hi for measuring set backs. The Gross Land Area: South Line = 50 + 192.65 + 181 = 260.75 North line = 50 + 213.19 + 17 = 280.19 Average Depth = 260.75 + 280.19 ; 2 = 270.47 270.47 x 340 = 919959.8 ; 43560 = 2.111 Acres. - 1570 G.P.Acre x 2.111 = 3314.4 G.P.D. Max. The owner proposes to build a 12 unit condo with 2 bdrms. each for 24 Bedrooms x 120 = 2880 g.p.d. 3314 - 2880 = 434 g.p.d. additional allowable wastewater. L(,cont. . ) Page 1 of 2. . .Shin Project. 0 Under EPA Guidelines of 14.5 Gallons Per Employee for stores or office buildings, the maximum number of Employees would be 29.96 or less than 30 full time Employees. Test Holes indicate that the soil is a sandy, gravelly loam that should be enhanced by providing a 12" layer of medium sand below the Drain gravel. This will give good protection to the ground water and allow an application Rate of 0.96 g ft2 per day. The water table at Test Holes 1-2 & 3 is at Elevation 22D to 234. The water table at Test Holes 4-5 & 6 is betweenl9.55 and 20.�. Using sand lined beds Ten feet wide by 100 feet long in the area of test holes 4 & 5 will allow Grading to Elevation 23.01, Replacing with sand to Eley, �4 to provide a vertical separation of 4 feet from gravel to g.round water. c9e � � j D F rn i.(,, �lot,Gl �S j brrti� 141011 fgplres i kifFlIt3o Additional trenches adjacent to the Hiway (if usey for store buildings) should be kept 3 feet wide, excavated to Elev. 24. and replaced with 2 feet of sand to Elev. 26.0. This will require a Modi- fled Mound to provide cover for the trenches. (-If full allowable gallonage is used, the trenches will be 3 feet wide by 150 feet long. Drawing #1 shows locations of elevations used and test holes. Drawing # 2 shows locations of proposed Condo, septic tanks, pump chambers, and drainfield. Drawing # 3 shows possible drainfield area if other conditions permit additional store or office buildings on site. Calculations, Specifications and Special Requirements are provided on separate sheets. Page 2 of 2. . .Shin Project. �! �f A i r 'TH � A i I I H TN TH toA-r l o c er y-t 0>-7 s f ARNOff., tARJA G - 4 Cert fted De7ugner 910. Box 321 (2 ) 8077-92" Q 9JrvN 1i r%^rt 'WA CWCAO ARNOLD TAINUA Xo b: Certified Designer 0 Q. Box 323 (2%) 8' 14M �. ffaodsuort._WA 9048 Sv R v'e-( bate: 00 •e d��► 2 7 7 3 S lv. JO)d COP q' flZ �JL4Vol 6 - 7-0s7 fib/e C,PoC,�.d 4W( � ? 21 ? -P"NE Gs 25 zs 7 ! s�- cl G tOtJ e ve l z 5 714 141 - T e.st YO/C /, eVel Ys 22 �6 'F -- %SS l ale ' G reed 4 c✓e 9 � o�' 4J C' • © 2 a76ev eV12 p 35 ! 9 35 �l Yoctttc @ 40?Ey- e.5-i //old- e ve 7 7 Zv .2 ve RL Ae : I2esery e 13 Raw o r �. j2Z e I re / SW sur v m kr I is illsu�a ys Pw5 efybr or unropm a .AWNOLD TAH4. j�Ur Id Cent: red Desrgrter Q. Box 3A (m6) �- Sfmdsvori.WA ARNOLD TAHJA Robert Shin Certified Desigtttar p 0. Sox 323 (� V7* Store or Offices unodsvon. WA Buildings. If land use conditions allow buildings other than the proposed twelve unit condominiums, the septic system for these buildings will be designed for a limit of 434 gallons per day. This will require a 1250 gallon septic tank, pump and accessories as needed, and sand lined trenches adjacent to the highway right-of-way. Since there is no definite plan available at this time, the feasibility of this section depends on space being available- for additional buildings and parking. ( Arnol ) S TA TE w ,. i9 VA/L ,4 &4e d d i c Ss.9 s iFi�Q Id 1 i DATE �/—? 9�- ARNOLD TAIUA Certified Designer, 9 U. Box 323 (206) 877-9259 Waodsvoh.WA 9954 Robert Shin Twelve Unit Condo Breaking this into two equal units of six units each will produce Unit 1 (6 x 2 x 120 = 1440 G.P.D) Unit 2 - Same Unit 1 will have two 1,150 Gal. or larger septic tanks- (Required is 150% of 1440 2160). a 110 gallon pump chamber and pump, and accessories. Unit 2 will be the same as unit 1 in every detail. Typical;- Three in Unit 1. and three in Unit 2 for six 2 ,SrAaf ryes total units 18 laterals w/ six- 3/16t1 holes each on 501/ O.C. = 108 orifices o d � 11 x •59 = 63.72 G.P.M. 251 x 1211 = 300 inches. fi � s Use pumps capable of providing 65 gpm to 251 heads with counters and timers for monitoring. ARNOLD TA MA Certified Dwignv O. Box 323 (2m) 8Tf4" woodsvott. WA 98M iz i ADDENDUM Robert Shin Calculations. Specifications & Special Requirements Twelve (12) - two bedroom condominiums will produce (120 x 240 = 29880 gallons per day) a septic quantity of 150% 4320 gallons per day. Plumbing is to be done in such a manner that these are two separate outlets which will produce two (2) 1440 gallon .units. provide each unit with two (2) 1150 or 1200 gallon septic tanks, (a total of four tanks). Provide each unit with a separate pump chamber and accessories. i Each unit will pump to three (3) 10 x 50 foot beds, These i sand-lined beds will have three (3) - 1�11 laterals with 3/16" orifices at 48" o/ct (11 at 6 o"clock and one at 12 o' clock on i middle laterals), 3 x 12 x 3 x .59 = 63.72 g.p.m. Using 2110 pump transfer lines to laterals will require pumps capable of providing 65 to 70 gpm to 20 foQt plus head. Provide spray ports at distal ends of center laterals (six). Provide counters and timers at each pump. The owner will enter into a monitoring and service agree- ment satisfactory to the Health Department before using system. ICI 3/3 9/ (Arno id ja) ARNOLD TA113A Certified Designer P.O. Box 323 (M) 877-9259 Aug. 229 1988 uoodsnorfs WA %548 MASON COUNTY p ENVIORNMENTAL HEAL 'T ANDERSON / SOMERS COM SHELTON WA. 98584 uUG N 198Q SITE. ALLYN, WA. Mr. John Dennison: GENERAL SERVICES In response to your memo on this matter, the owners are aware of the requirements mentioned in items 1 thru 5. Item (3) should pose no problems since the Shoreline Master Program as ammended on March 1, 1988 classifies this property as URBAN COMMERCIAL. Item (4) (DOT Permit) should be satisfied by the fact that Lakeland Ave. bord- ers the property and serves as access-egress. If we direct our attention to Enviornmental Health only at this time, space available and soil conditions should be our only-concern. The total useable land area available is 300 X 21�+20 _62,7OU0Fk_ �r 6 sqare feet. Maximum allowable wastewater of 1570 pd per acre will t OK - g �S�tal^�,►p. allow 2,�59.fs7 g .lens per day. 60-1 �y3,5G4 =��yly15,70)- 2�259..8S 0.7 .3/y With an application rate of 0>4 (class g) standard-trenching or c 2;g2 .SAz� beds would require 3,I9` 8 square feet of area. Doubling this to pro- vide a 100% reserve will require 694uu square feet, Reducing the total area by 100 feet from water and 5 feet per side for setbacks translates into 62,700 less 33,590 square feet of * suitable drainfield area. <Aet.0 Z; { leaving 29,110 square feet of useabl�. ) 1 Since the required drainfield and (�ct' �q�0) q reserve will only require 22% of the acceptable area, it seems that any reasonable placement of struc- tures and parking areas will satisfy this need. f Continued Page 2 ANDERSON/SOMERS COMMERCIAL SITE-- ALLYN WA. In addition to the suitable drainfield area, the entire 100 bt 300 foot setback area could be used for structures or parking creating a ratio of 6,400 max. needed against 62,700 available. mof<'%an egotkk-i- If a six-plea were 1250 square eet per unit, the area of the six-plea, drainfield, and reserve area would total 13,900 feet, leaving 48,800, or enough for 244 parking spaces. (10 X 20). It appears that the only limit on liquid waste is 1570 gallons per acre per day (WAC 248-96-090) (b) Method LL (i), and any permit for less than 2259 gallons per day should be acceptable. I am requesting that you approve the permit as submitted, stip- ulating that location and drainfield design be re-evaluated at time of construction. Sincerely , Arnold Tahja cc HARLEY SOMERS �l �nof �� l�sC un��s given a l 0012s&r 15more #,712 ad , 1 ell the Se 5 ?�J v e r o �/S 21 0 z rrl-, I1/a rrLZ S �'S