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Home My WebLink AboutSWP272844 Lk Short Plat'(SHPLI L f LkW O a I I REQUEST FOR PROJECT t# Prelim Plat (PPE# CAG# ) To: Technical Services Date W0f Green# From: Plan Review/Project Manager Cam I I I G n Project Name 1 �r I ��C1 C clhc� P I'— P()in' 4 Qg\� L L C (70 characters max) ` Descri lion of Project: 0!A+. 1 ` _0�,8L-" � 3yc.A�' �-V� Sewer0 i �e Frcm�t i n� c� +r G . ��eqG en QQ Circle Size of Waterline: 10" 12" Circle One: New or Extension Circle Size of Sewerline: 8O 10" 12" Circle One: Ne or Extension Circle Size of Stormline: 12" 15" 18" 24" Circle One: et or Extension Address or Street Name(s) 39 r-K a hy-�h Dvlpr/Contractor/Owner/Cnslt:: Cct i 0 r-er-%r\ S70 characters max) Check each discipline involved in Project Ltr Drwg #of sheets per discipline Trans-Storm (Roadway(Drainagc) (Off sit`improven=cs)(includc basin name) (include TcSC sheds) ❑ Transportation (Signalization,Channclizadon,lighting) ❑ ❑ Wastewater Sanitary Scwu Main(include basin name) { Water (Mains,Valves,Hydrants) / (Include compositc i Horizontal CLi Shcus) C]_ Suface Water b ❑ Improvements (CLP ONLY)(includc basin name) TS Use Only wwP -ate tiv�- a-7- i TERI PLACE TECHNICAL INFORMATION REPORT TABLE OF CONTENTS SECTION I: PROJECT OVERVIEW SECTION II: HEARING EXAMINERS REPORT SECTION III: LEVEL I OFF-SITE ANALYSIS SECTION IV: STORM DRAINAGE INFORMATION SECTION V: CONVEYANCE SYSTEM ANALYSIS AND DESIGN SECTION VI: SPECIAL REPORTS AND STUDIES -N.A. SECTION VIII: OTHER PERMITS-NONE REQUIRED FOR THIS PROJECT SECTION IX: EROSION AND SEDIMENTATION CONTROL SECTION X: N.A. SECTION XI: MAINTENANCE AND OPERATIONS MANUAL APPENDIX: COPIES OF TABLES REFERENCED IN THIS REPORT TERI PLACE T TECHNICAL INFORMATION REPORT SECTION I PROJECT OVERVIEW I. NARRATIVE: A. Existing Site Conditions: The site is rectangular in the East—West direction. The high point (EL=127+/-) is located at the southwestern side of the site in the vicinity of the existing garage located on the property to the south. The low point (EL=120+/-) is at the northeastern portion of the site in the vicinity of the northwestern corner of proposed Lot#6. The elevation change across the site is 7.0'+/-. The average slope across the site is approximately 5%. There are only two (2) significant trees within the site. The trees have been field surveyed and are shown on the Preliminary Short Plat Map. The remainder of the site is covered with low growing pasture grass. There is an existing residence and several associated structures within the site that are to be removed. Stormwater generated from the site partially infiltrates during the drier part of the year or flows overland to the north where it enters the property to the north of the site. There are no defined drainage features within the site. The soils within the site are Indianola Series(Type A). B. Proposed Site Conditions: In the developed condition, the site is proposed to be subdivided into 6 single-family residential lots. A storm system water quality tank is proposed to be located within the access easement on the northern portion of the site. Stormwater leaving the water quality tank will discharge into the existing conveyance system on the eastern side of Park Ave. N. The Downstream system, and a discussion of possible improvements to the downstream system is described in Section III of this Report. C. Response to King County SWDM Core Requirements Core Requirement #1 : Discharge at the Natural Location In the existing condition, stormwater runoff generally sheet-flows across the property in a northern direction. In the developed condition stormwater will be conveyed to the existing storm drainage system on the East side of Park Avenue North. The point of convergence of stormwater leaving the site between the Existing and the Developed Condition is at the intersection of Park Avenue N. and North 40`h Street. The distance from the location where stormwater leaves the site as shown on the existing condition Exhibit and the point of convergence is approximately 400'. Core Requirement #2: Off-Site Anal This information is provided in Section III of this Report. Core Requirement #3: Runoff Control The analysis provided in Section IV of this Report shows that due to the small size of the site, detention is not required. Sect. 1.2.3. of the K.C.S.W.D.M. (Manual) contains a provision allowing for an exemption from onsite peak rate runoff control. A recently approved project—Miller Short Plat, located to the southeast of the site, was allowed to use the exemption. A water quality tank has been designed for the site. The tank is located within the access easement. The design of the water quality tank within the Teri Place project is similar to the design of the tank within the approved Miller Short Plat project. Core Requirement#4: Conveyance System Stormwater runoff generated from the site in the developed condition, as presented in this report, will be conveyed to the existing storm conveyance along the East side of Park Avenue North. Core Requirement #5: Erosion/Sedimentation Control Plan Due to the small size of the site, the gentle slopes, and the existing soils, it is anticipated that there will be minimal potential for erosion during the construction of the access road, utilities, and residences. The engineering design of the project will contain a separate Temporary Erosion and Sediment Control Plan(TESCP). The TESCP plan is provided on Sheet 5 of the engineering plan set. D. Response to King County SWDM Special Requirements: A review of the Special Requirements appears to indicate that none of them will apply to this project. A Vicinity Map is attached. A copy of a portion of Sheet 5 of the King County Soil Survey Map is attached. A Completed T.I.R Worksheet is Attached r 9300 N a e for SE 0\ ¢ Wxir L FS PIONEER 8 m. s 3 6_i -m A �NSL rolx sr I_] G.x n s sE y� sE T FQ ry Ej Jy PART( P\ 8 S , oz yr st lst�^ 75s SE 2 D f 7Est SEE x 7lsr sr< E 7 N7nS` �F T1 `:ti.:3O� s rs>^ PK ,E•• l` r 7's�� < CC� 7S TT 4 < s . BT j D C LOB ii f sr P ST .. s c _ AT .• 129 0`, sC n lq x sE r6M 1` t>tx ,"MID I _s $ %• .. .167H ST onr i - J. tirsr NEIrGLSTIE PL ggSE t,75iM � LAA 1Z'NE B `n t.. rej nix v S 9W "i erH & A', rN \ r„ y T7�� tv OC 4 kpa. ` S T T`ti � •-' SE.'` ��.," � �.$' a v"ry ? 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KING COUNTY AREA, `NASHINGTON NO. 5 Page 1 of 2 King County Building and Land Development Division TECHNICAL INFORMATION REPORT (TIR) WORKSHEET PARTA PROJECT OWNER AND PART 2 PROJECT LOCATION PROJECT ENGINEER DESCRIPTION ProjectOwner Project Name /C/-I� Address Location Phone �Q�- ys.�- Township Z 7W Project Engineer Range s� Section /V 141/y -53Z Company Project Size AC /.OZ Address Phone Upstream Drainage Basin Size AC PART 3 TYPE OF PERMIT APPLICATION PART 4 OTHER PERMITS yZS-Zoy-�/8� = Subdivision = DOF/G HPA = Shoreline Management Short Subdivision = COE 404 C Rockery Grading 0 DOE Dam Safety C Structural Vaults Commercial C FEMA Floodplain CI Other �] Other 0 COE Wetlands C HPA I COMMUNITYPARTS SITE AND DRAINAGE Community 7 Drainage Basin PARTS SITECHARACTMISTICS 0 River Floodplain 0 Stream 0 Wetlands L� Critical Stream Reach C; Seeps/Springs Depress io ns/Swales 0 High Groundwater Table 0 Lake Groundwater Recharge 0 Steep Slopes Other Lakeside/Erosion Hazard • Soil Ty pe Slo s Erosion Potential Erosive Velocities 1/7C O - �yo Additional Sheets Attatched 1/90 Page 2 of 2 King County Building and Land Development Division TECHNICAL INFORMATION REPORT (TIR) WORKSHEET PART'S-ZIEVELOPMENT.LIMITATIONS REFERENCE LIMITATION/SITE CONSTRAINT Ch.4-Downstream Analysis 0 u J Additional Sheets Attatched PART'S ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION FOLLOWING CONSTRUCTION Sedimentation Facilities Stabilize Exposed Surface Stabilized Construction Entrance Remove and Restore Temporary ESC Facilities Perimeter Runoff Control Clean and Remove All Silt and Debris Clearing and Grading Restrictions Ensure Operation of Permanent Facilities Z Cover Practices O Flag Limits of NGPES Construction Sequence C Other C Other PART'10 SURFACE WATER SYSTEPA, Grass Lined Channel Tank'Wa Infiltration Method of Analysis Pipe System C Vault 0 Depression CO 2 yh/^ I Open Channel C Energy Dissapator = Flow Dispersal Compensation/Mitigation C Dry Pond r Wetland C Waiver of Eliminated Site Storage Wet Pond C1 Stream Regional Detention Brief Description of System Operation 171�C /7 0I'f/J /Jo/J�i 157 O 7— 7' Ce Cj CGGSS cYSGC.�T Facility Related Site Limitations 0 Additional Sheets Attatched Reference Facility Limitation (May require special structural review) 0 Drainage Easement Cast in Place Vault Other 0 Access Easement C Retaining Wall Native Growth Protection Easement Rockery>4'High Tract Structural on Steep Slope Other SIGNATUREOF PROFESSIONAL I or a civil engineer under my supervision have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attatchments. To the best of my knowledge the information provided here is accurate. 1/90 TERI PLACE TECHNICAL INFORMATION REPORT SECTION II HEARING EXAMINERS REPORT This Section II of the T.I.R. contains the following information. 1. Copy of February 14, 2000; Hearing Examiners Report and February 14, 2000 OFFICE OF THE HEARING EXAMINER CITY OF RENTON REPORT and DECISION APPELLANT: Robert West Appeal of Administrative Determination Re Teri Place Short Plat File No.: LUA00-009,AAD APPLICANT: Robert West Teri Place Short Plat File No. LUA99-183,ShP1-H LOCATION: 3906 Park Avenue N SUMMARY OF APPEAL: Appeal administrative decision regarding private street access SUMMARY OF REQUEST: To subdivide 1.02 acre parcel into seven lots intended for single-family residences. PUBLIC HEARING: After reviewing the Appellant's written request for a hearing and examining the available information on file,the Examiner conducted a public hearing on the subject as follows: MINUTES: APPEAL The following minutes are a summary of the January 25, 2000 appeal hearing. The official record is recorded on tape. The hearing opened on Tuesday, January 25, 2000, at 9:00 a.m. in the Council Chambers on the seventh floor of the Renton City Hall. Parties wishing to testify were affirmed by the Examiner. The following exhibits were entered into the record for the appeal: Exhibit No. 1: Yellow appeal file No. LUA00-009, Exhibit No. 2: Yellow file No. LUA99-183,ShP1-H, AAD, containing the appeal, proof of posting and containing the original application, proof of posting publication, and other documentation pertinent to the and publication, and other documentation pertinent to appeal. the file(by reference) Exhibit No. 3: Letter from Mr. Watts dated 115100 Exhibit No. 4: Plan of 7-lot plat dated 10/23/99 Exhibit No. 5: Letter and drawing from Mr. Casey Robert West Appeal and Short Plat Hearings File Nos.: LUA00-009, AAD LUA99-183, ShPI-H February 14, 2000 Page 2 Parties present: Robert West, Appellant Representing City of Renton 2903 Powerhouse Road Peter Rosen Yakima, WA 98902 1055 S Grady Way Renton, WA 98055 The Examiner explained that the appeal was an administrative appeal held pursuant to Ordinance 3071 and was the only administrative review to occur on the matter. The matter may be submitted back to the Examiner for reconsideration if the parties are not satisfied with the decision. He stated that the appellant had the burden of demonstrating that the City's action was erroneous, and would have to show clear and convincing evidence that the City's determination was incorrect. At that point the City could respond, if they chose to do so. Robert West, appellant herein, stated that in October 1999, a pre-application meeting was held with the City staff regarding the proposed Teri Place Short Plat. In that proposal appellant asked to be allowed to develop 7 lots within approximately 1.02 acres. City code provides that you can access up to 6 lots with a private street or easement. Appellant proposed to access 5 lots with the private street, Lot 2 being accessed from a pipestem, and Lot 1 being accessed from Park Avenue. There is a private access street running parallel to the north boundary of the property, with a hammerhead turnaround on the east end of the property that straddles Lots 5, 7 and 6. The code further states that no more than four of the lots cannot be abutting a public right-of-way. Appellant proposes five not abutting a public right-of-way. Under the modification procedures in the code, a modification can be granted if it is first found that a specific reason makes the strict letter of the code impractical and that the modification is in conformity with the intent and purpose of the code. Appellant believes the specific reason for modification is that this lot is 428 feet in length, and is the longest parcel in the Kennydale region that does not have either an existing or a potential for another access from a public right-of- way. The City had responded that it was similar to other parcels, but appellant disputed that finding. The City also presented an alternative suggestion to achieve access to the seven lots. Appellant, however, felt there were flaws in the City's suggestion and enumerated several of them. On November 23, 1999, appellant officially requested a modification. Appellant also discussed options available to them such as using a shared driveway or eliminating a lot, but restated their preference for a modification which would allow them to proceed with the 7-lot short plat. Mr. West also noted that they had support from surrounding property owners to their requested 7-lot short plat. In summary, Mr. West concluded that their proposal conformed to the City's standards pertaining to zoning, density, lot sizes, setback requirements and number of lots allowed to be accessed from a private street. Their request for a modification was to allow five lots which would not be abutting a public right of way. David Casey, 15 S Grady Way, 4400, Renton, Washington 98055, appellant's engineering representative herein, gave a brief history on the discussions with the City and the alternative options presented. He reiterated the problems with the City's suggested alternative such as increased grading, additional impervious surface, and the location of a garage just south of the south boundary line. He questioned the arbitrary nature of the number of lots not to be abutting a public right of way as four, not five, not three. Mr. Casey concluded that granting their appeal would be for the benefit of the health, safety and welfare of the community. Christopher Brown, 9688 Rainier Avenue S, Seattle, Washington 98188, appellant's traffic engineer, discussed the advantages of the applicant's proposal with the seven lots such as increased tax revenue and enhanced ` Robert West Appeal and Short Plat Hearings File Nos.: LUA00-009, AAD LUA99-183, ShPI-H February 14, 2000 Page 3 population density. After consulting with the City's street maintenance department, it was thought that the applicant's proposal also reduced impervious surface with less water runoff. The post office, fire and police departments would also only have one street to locate. Mr. Brown also discussed the parking, backing out and traffic flow of the proposals. Mr. West clarified the type of street improvements that applicant proposes for the site. Neil Watts. Plan Review Supervisor, Development Services Division, City of Renton, 1055 S Grady Way, Renton, Washington 98055 testified for the City. He clarified that the City's letter to appellant dated January 21, 2000, was not an analysis of alternatives, but a statement of what the code would allow. It was not an indication of staffs support of an alternative option. Mr. Watts further explained the density calculation process, as well as street improvement standards. Peter Rosen clarified that Mr. Watts' letter of January 21, 2000, was in response to Mr. Brown's letter of January 19. He further explained that an applicant must meet all the development standards, and not meeting one does not justify a modification of one of the standards. Closing arguments were given by the parties and their comments reiterated their previous statements. The Examiner called for further testimony regarding this appeal. There was no one else wishing to speak. The hearing closed at 10:25 a.m. FINDINGS, CONCLUSIONS & DECISION Having reviewed the record in this matter, the Examiner now makes and enters the following: FINDINGS: 1. The appellant, Robert West for Hi-Point LLC, filed an appeal of an administrative determination that allowing five interior lots to be accessed by a private road was not permitted. 2. The appellant owns an approximately 1.02 acre parcel of property located at 3906 Park Avenue North. The subject site is located on the east side of Park Avenue two parcels south of N 40th Street. 3. The subject site is zoned R-8 (Single Family; Lot size-4,500 sq. ft). 4. The map element of the Comprehensive Plan designates the area in which the subject site is located as suitable for the development of single family use, but does not mandate such development without consideration of other policies of the Plan. 5. The subject site is approximately 427.34 feet deep (east to west) by approximately 103.39 feet wide. The 103 foot dimension is the site's frontage along Park Avenue N. 6. The appellant proposed dividing the subject site into seven (7) lots. Robert West `Appeal and Short Plat Hearings File Nos.: LUA00-009, AAD LUA99-183, ShPI-H February 14, 2000 Page 4 7. Proposed Lots 1 to 5 would be arrayed one after another from Park eastward into the site. Generally, Proposed Lots 1 to 5 would be located along the south boundary of the subject site. Proposed Lots 6 and 7 would be stacked at the eastern boundary of the site with Proposed Lot 6 in the northeast corner of the site and Proposed Lot 7 in the southeast corner of the site. 8. Proposed Lot 1 would abut Park Avenue and would take approximately 77.4 feet of the frontage along Park Avenue. The remainder of the Park frontage, approximately 26 feet, would be a pipestem extension of Proposed Lot 2. Therefore, Proposed Lot 2 would have a 26 foot wide extension that abuts Park Avenue immediately north of Proposed Lot 1. In this case, by definition (legally), both Proposed Lots 1 and 2 directly touch, abut or are located on a public street, Park Avenue North-- Proposed Lot 1 because its western property line coincides with the street, while Proposed Lot 2 connects by way of its 26 foot wide pipestem or tentacle that extends approximately 70 feet west from its main section. 9. The remaining five lots, Proposed Lots 3 through 7, would be located on the interior of the site and none of them would have a property line that abuts Park Avenue North. Their access, as proposed by the applicant, would be over a private easement roadway that passes from Park, across the pipestem for Proposed Lot 2, and then traverses along the north side of Proposed Lots 3 and 4 and ends in a hammerhead turnaround located in parts on Proposed Lots 5, 6 and 7. The roadwav would be 26 feet wide which corresponds with the width of the pipestem, and approximately 360 feet long. 10. The hammerhead turnaround would accommodate vehicle maneuvering and allow them to turn around and exit the site without having to back up the length of the roadway. 11. Section 4-6-060(J)(1) provides the following regulations governing the development and use of private roads: 1. When Permitted: Private streets are allowed for access to six(6) or less lots, with no more than four(4)of the lots not abutting a public right-of-way. Private streets will only be permitted if the proposed private street is not anticipated by the Department to be necessary for existing or future traffic and/or pedestrian circulation through the subdivision or to serve adjacent property. 12. In other words, code may permit not more than four(4) interior lots that do not have any property line in common with a public street to be served by a private or easement street. In this case the appellant has proposed that the private road serve five fully interior lots, one more than permitted by Code. Therefore, the appellant applied for a modification under the following provisions: Section 4-9-250(D) MODIFICATION PROCEDURES: I. Application Time and Decision Authority: Modification from standards, either in whole or in part, shall be subject to review and decision by the Planning/Building/Public Works Department upon submittal in writing of 'Robert West Appeal and Short Plat Hearings File Nos.: LUA00-009, AAD LUA99-183, ShPI-H February 14, 2000 Page 5 jurisdiction (sic, probably should read "justification") for such modification. (Amd. Ord. 4777, 4-19-1999) 2. Decision Criteria: Whenever there are practical difficulties involved in carrying out the provisions of this Title,the Department Administrator may grant modifications for individual cases provided he/she shall first find that a specific reason makes the strict letter of this Code impractical, and that the modification is in conformity with the intent and purpose of this Code, and that such modification: a. will meet the objectives and safety, function, appearance, environmental protection and maintainability intended by the Code requirements, based upon sound engineering judgment; and b. Will not be injurious to other property(s) in the vicinity; and C. Conform to the intent and purpose of the Code; and d. Can be shown to be justified and required for the use and situation intended; and e. Will not create adverse impacts to other property(ies) in the vicinity. (Ord. 4517, 5-8-1995) 13. It appears that there were a number of meetings, correspondence and discussions regarding the proposal. On November 23, 1999 the appellant submitted its formal request for a modification. The appellant claimed that the modification was necessary to create the maximum number of lots, seven (7) lots, permitted by the underlying zoning and density regulations. 14. The City denied the modification on January 5, 2000. It was noted that the density provisions would allow a density that ranges between 4 and 7 (after reducing the acreage of the pipestem) and that creating seven lots as proposed by the appellant was not mandatory. Staff did not believe that this reduction of one lot created an impractical outcome. 15. The appeal was filed on January 18, 2000 and was timely filed. Its main points are that the option to provide a second pipestem access along the south side of the plat would: a. Create three "double-fronted" lots, b. Three access points within 80 feet, and C. 2,700 square feet of additional impervious surface. 16. The appellant claims the proposed private road that serves five fully interior lots is appropriate. The appellant noted the approval of the modification does not create any undue harm, is engineeringly Robert West "Appeal and Short Plat Hearings File Nos.: LUA00-009, AAD LUA99-183, ShPI-H February 14, 2000 Page 6 sound and discourages parking. The appellant also noted that the subject lot is longer than other lots in the immediate vicinity and serving the five lots that can be carved from the rear of the subject site requires the modification. Further, a modification allows the appellant to provide one additional lot which meets the City's density guidelines and the Growth Management goals. 17. The City maintains that the more homes served by a private road, the more complex the ownership and maintenance issues. Staff also noted there are more pedestrians including students relegated to walking in the road instead of walking on an established sidewalk that would be required as part of a public street. There are more parking problems since there is no room along a private road to support guest or resident parking. CONCLUSIONS: 1. The appellant has the burden of demonstrating that the decision was either in error, or was otherwise contrary to law or constitutional provisions, or was arbitrary and capricious (Section 4-8-11(B)(4). The appellant has failed to demonstrate that the action of the City should be modified or reversed. The decision of the City is affirmed. 2. Arbitrary and capricious action has been defined as willful and unreasoning action in disregard of the facts and circumstances. A decision, when exercised honestly and upon due consideration of the facts and circumstances, is not arbitrary or capricious (Northern Pacific Transport Co. v Washington Utilities and Transportation Commission, 69 Wn. 2d 255, 259 (1969). 3. An action is likewise clearly erroneous when, although there is evidence to support it,the reviewing body, on the entire evidence, is left with the definite and firm conviction that a mistake has been committed. (Ancheta v Daly, 77 Wn. 2d 255, 259 (1969). 4. The appellant has failed to demonstrate that the decision was founded upon anything but a fair review of the application as it pertains to the proposed private road. The appellant has failed to demonstrate with cogent evidence that a mistake was made. 5. Since the burden of demonstrating error is on the appellant, this office can reach no other conclusion but that staff made the correct determination. The proposed modification is not appropriate and cannot be approved administratively. The decision below must be affirmed. 6. Looking at the immediate intent of the Modification provisions wherein it states: "Whenever there are practical difficulties involved in carrying out the provisions..." it appears that there is no reason to approve a modification. There do not appear to be any practical difficulties in developing the roadway as required by Code. There are no topographic difficulties in providing access to only but not more than four lots that do not abut a public roadway. There are no length or width constraints to providing a road that meets the requirements of providing access to only four lots that do not abut a public roadway. The depth or length of the lot is not a practical difficulty to road building. The code provision is aimed at the number of lots to be served by a private road. Code Robert West Appeal and Short Plat Hearings File Nos.: LUA00-009, AAD LUA99-183, ShPl-H February 14, 2000 Page 7 draws a clear limitation at four lots. Code does not allow a private road to provide access to five lots where all five lots are interior and none of them abut any portion of a public street. If five completely interior lots are to be served then at that point the Code requires that a public road be created to provide access to the five or more lots. As staff noted, if five lots are allowed by this determination,why not six or seven the next time someone wants to develop interior lots. There is no reason to diverge from the stated standard. 7. It is clear that there is no practical difficulty in providing access. There are two solutions. One would be to reduce the total number of lots to six which would make not more than four interior lots accessible by the private road. A second solution would be to provide a public half street. 8. One other option was a suggestion that a second pipestem be created along the south boundary of the subject site that connects interior Lot 3 directly to the street. The appellant responded to this possible option in their appeal letter where they stated: "We feel that his suggestion runs so counter to sound engineering, and good planning that it could not possibly serve the public health, safety, or welfare." 9. The only issue is whether the site can be developed as a seven lot plat as opposed to being limited to being developed as a six lot plat. That does not appear to be a practical difficulty. The access to this additional interior lot violates a code limitation. Both a six-lot plat or a seven-lot plat meet the density requirements of the Comprehensive Plan and the Zoning Code. Therefore, the modification is not necessary to meet the minimum requirements of density found in the City regulations. 10. The provision requires the Administrator to find "that a specific reason makes the strict letter of this Code impractical." It appears that the Administrator did not find any specific reason why five interior lots should be served by private road. 11. As a matter of fact, it appears that staff has taken liberties in allowing one interior lot to use a pipestem where the narrow pipestem's end abuts a public roadway and then allowing four(4) more interior lots to cross the pipestem as an easement driveway. While it may meet the letter of the law its effect is to allow what the code otherwise attempts to avoid - complicated ownership and maintenance, parking restrictions and pedestrian safety. It certainly pushes the definitions of"private road" and pipestems and the number of permitted interior lots. 12. The determination below must be upheld since there was nothing in the record to allow this office to conclude the decision below was either clearly erroneous or arbitrary and capricious. DECISION: The appeal is denied. ************************************************** Robert West Appeal and Short Plat Hearings File Nos.: LUA00-009, AAD LUA99-183, ShPl-H February 14, 2000 Page 8 MPIUTES: TERI PLACE SHORT PLAT The following minutes are a summary of the January 25, 2000 major amendment hearing. The legal record is recorded on tape. The hearing opened on Tuesday, January 25, 2000, at 10:35 a.m. in the Council Chambers on the seventh floor of the Renton City Hall. Parties wishing to testify were affirmed by the Examiner. The following exhibits were entered into the record: Exhibit No. 1: Yellow file containing the original Exhibit No. 2: Vicinity map application, proof of posting, proof of publication and other documentation pertinent to this request. Exhibit No. 3: Short plat map Exhibit No. 4: Utilities and road plan Exhibit No. 5: Appeal file LUA00-009, AAD(by reference) The hearing opened with a presentation of the staff report by PETER ROSEN, Project Manager, Development Services, City of Renton, 1055 S Grady Way, Renton, Washington 98055. Applicant requests approval to subdivide 1.02 acres into seven lots for single family development. The proposed lots range in size from 5,409 to 7,813 square feet, for a net density of 6.86 dwelling units per acre. There are existing structures on the site which will be demolished as part of the proposal. The site topography slopes slightly toward the east. The Comprehensive Plan (CP) designation for this site is Residential Single Family, and is intended to promote and enhance single family neighborhoods. The proposal is consistent with its designation in that it would provide for construction of single family homes and promotes goals of infill. It also meets lot size and density, and is consistent with recent subdivisions in the vicinity of the site. The site is zoned R-8,Residential - 8 dwelling units per acre. The minimum lot size is 4,500 square feet. The R-8 zone allows for a density range of a minimum of 5 and a maximum of 8 dwelling units per acre. The proposal of a private street with six lots or a public street with five lots will also meet the density requirements. The proposed lots.meet the lot dimension requirements, as well as the setback and height limits of the R-8 zone. The proposed private street exceeds 300 feet in length. City staff has recommended that residences on Lots 5, 6 and 7 have sprinkler systems, and that the hammerhead turnaround meet the Fire Department standards and be clearly marked for no parking. Police and Fire departments have indicated sufficient resources exist to provide service to this proposed development. This project is expected to have an impact on City services, and staff is recommending payment of fire, parks and traffic mitigation fees. The Renton School District is not expected to be adversely impacted by the 3 to 4 school age children from this development. A storm water detention tank is proposed to be located under the private street at the north end of the property. Water and sanitary sewer utilities are available to serve the proposal. Regarding street improvements, if a private street is approved then the applicant will be required to create a homeowners association with a Robert West Appeal and Short Plat Hearings File Nos.: LUA00-009, AAD LUA99-183, ShPI-H February 14, 2000 Page 9 maintenance agreement to maintain the private street and other common improvements on the site. The applicant is required to improve the site frontage along Park Avenue N with sidewalks, curb, gutter and street lighting. Staff made an error in terms of recommending approval of the short plat as proposed. As proposed it does not meet street standards. It would with the granting of a modification or with a revision of the plat. The issue of access needs to be resolved prior to approval of the short plat. At this point staff is recommending the two alternatives outlined in Mr. Watts' letter of January 21, 2000, which is either six lots with a private street, or a half street with public street improvement which would result in five lots. Further staff recommendations are: (1) applicant demolish the existing structures on the site prior to recording of the short plat; (2) applicant provide a minimum of five feet of landscaping between the private street and the north property line; (3) payment of fire, parks and traffic mitigation fees; and (4) applicant shall create a homeowners association or maintenance agreement to maintain the private street and other common improvements on site. Robert West, 2903 Powerhouse Road, Yakima, Washington 98902, applicant herein, suggested that the landscaping required at the north property line be reduced to three feet. David Casev 15 S Grady Way, #400, Renton, Washington 98055, applicant representative herein, stated that they were not in support of the five lots with a public street. If their appeal was denied, they wanted to keep the option of six lots with a private street. He also questioned whether a 6 foot high solid fence on the north property line would be acceptable instead of the required 5 foot landscaping. Mr. Rosen responded that a 3- foot landscape buffer allows only a ground cover; that a 5-foot strip provides space for a mid-size shrub that would provide a buffer. Sam Robbins, 3900 Park Avenue N, Renton, Washington 98056, an adjacent property owner to the south, stated that any driveway on the south boundary would be a waste of land when there is a private road on the north boundary to serve the site. Olga Lissman, 3930 Park Avenue N, Renton, Washington 98056, an adjacent property owner to the north, stated she was in favor of the access drive on the north and none to the south. Mr. West responded regarding the two options proposed, one for a driveway only on the north side, and the other for a driveway on both the south and north boundaries. There was discussion among the parties regarding the timing of the reports and recommendations by staff and responses by the applicant. Neil Watts, Plan Review Supervisor, Development Services Division, 1055 S Grady Way, Renton, Washington 98055, explained the pre-application process regarding this proposal and the suggestions made to make this application comply with code. He further detailed the street improvements already in place on Park Avenue. The Examiner called for further testimony regarding this project. There was no one else wishing to speak, and no further comments from staff. The hearing closed at 11:20 a.m. FINDINGS: 1. The applicant, Robert West for Hi-Point LLC, filed a request for a 7-lot short plat together with a modification to allow five (5) interior lots to be accessed by a private road. Robert West Appeal and Short Plat Hearings File Nos.: LUA00-009, AAD LUA99-183, ShPl-H February 14, 2000 Page 10 2. The yellow file containing the staff report, the State Environmental Policy Act(SEPA) documentation and other pertinent materials was entered into the record as Exhibit#1. 3. The Environmental Review Committee (ERC), the City's responsible official, determined that the proposal is exempt from an environmental assessment. 4. The subject proposal was reviewed by all departments with an interest in the matter. 5. The subject site is located at 3906 Park Avenue North. The subject site is located on the east side of Park Avenue two parcels south of N 40th Street. 6. The subject site is an approximately 1.02 acre parcel. The subject site is approximately 427.34 feet deep (east to west) by approximately 103.39 feet wide. The 103 foot dimension is the site's frontage along Park Avenue N. 7. The subject site is zoned R-8 (Single Family; Lot size- 4,500 sq. ft). 8. The map element of the Comprehensive Plan designates the area in which the subject site is located as suitable for the development of single family use, but does not mandate such development without consideration of other policies of the Plan. 9. The subject site was annexed to the City with the adoption of Ordinance 2531 enacted in December 1969. 10. The subject site is fairly level. 11. The appellant proposed dividing the subject site into seven lots. That would have required a modification from the private road standards since a private road may not serve five interior lots. (For purposes of this discussion, "interior lot" shall mean a lot or lots that do not have any property line that abuts or is coincident with a public road.) Staff issued an administrative determination that the proposed private road could not serve five interior lots and denied the requested modification. 12. An appeal hearing was held concurrent with the land use hearing for this short plat. An administrative determination which accompanies this decision affirmed the denial of the modification. Therefore,the proposed private road may not be created to serve five interior lots. 13. The seven-lot configuration will be discussed although the modification required for its approval has been denied. This is because the applicant requested that if the proposed private road were not permitted, that other alternatives to creating a seven-lot plat be considered. These options would require either a public roadway into the plat(aligned in the same location as Proposed Lot 2's pipestem and the proposed private road) or an option that would create a separate pipestem to serve Proposed Lot 3 (see Exhibit 5 showing Option B). 14. Proposed Lots 1 to 5 would be arrayed one after another from Park eastward into the site. Generally, Robert West Appeal and Short Plat Hearings File Nos.: LUA00-009, AAD LUA99-183, ShPI-H February 14, 2000 Page I 1 Proposed Lots 1 to 5 would be located along the south boundary of the subject site. Proposed Lots 6 and 7 would be stacked at the eastern boundary of the site with Proposed Lot 6 in the northeast corner of the site and Proposed Lot 7 in the southeast corner of the site. 15. Proposed Lot I would abut Park Avenue and would be approximately 77.4 feet of the frontage along Park Avenue. The remainder of the Park frontage, approximately 26 feet, would be a pipestem extension of Proposed Lot 2. Therefore, Proposed Lot 2 would have a 26 foot wide extension that abuts Park Avenue immediately north of Proposed Lot 1. In this case, by definition (legally), both Proposed Lots 1 and 2 directly touch, abut or are located on a public street, Park Avenue North -- Proposed Lot 1 because its western property line coincides with the street, while Proposed Lot 2 connects by way of its 26 foot wide pipestem or tentacle that extends approximately 70 feet west from its main section. 16. The remaining five lots, Proposed Lots 3 through 7, would be located on the interior of the site and none of them would have a property line that abuts Park Avenue North. The access by private road has been rejected in an administrative appeal so the applicant would have to create a public road or half roadway in its place. 17. The applicant opposed creating a public road as it would be wider, provide parking and therefore encourage additional car ownership and car usage. The public road would eliminate the Lot 2 pipestem. 18. There would have to be an improved and approved turnaround for emergency vehicles. This would accommodate vehicle maneuvering and allow them to turn around and exit the site without having to back up the length of the roadway. 19. The other alternative would be to create a second pipestem along the south boundary of the subject site to Proposed Lot 3. This would reduce the lots served by the northern private road to a permissible four with Proposed Lot 3 served separately. This would create three lots that have roadways along both the north and south boundaries of those respective lots as well as having Proposed Lot 1 have a road along three sides. As the applicant stated in its appeal: "We feel that his suggestion runs so counter to sound engineering, and good planning that it could not possibly serve the public health, safety, or welfare." At the hearing the applicant also called the Option B"convoluted." 20. The proposed lots would vary in size from approximately 5,409 square feet to approximately 7,813 square feet. The lots are all sized greater than the 4,500 square feet required in the R-8 Zone. 21. The development of six lots would generate approximately 60 vehicle trips per day. Roads in the area appear capable of handling this load. The development of seven lots would generate approximately 10 additional trips per lot or approximately 70. 22. The development of the site will generate approximately 3 or 4 school age children. These students Robert West Appeal and Short Plat Hearings File Nos.: LUA00-009, AAD LUA99-183, ShPI-H February 14, 2000 Page 12 would be assigned to schools in the Renton School District on a space available basis. 23. Staff altered the recommendation that appeared in the staff report to a denial since the private road was not acceptable. 24. The City has adopted a mitigation fee standard for residential development as all development has an impact on roads, parks and fire services. The mitigation program imposes fees based on a per unit charge. This fee is generally imposed as part of the City's environmental review process and short plats are exempt from that review. That does not mean that the development of additional housing will not have impacts on those same services. The development of the subject site will have impacts on a variety of public services including surrounding streets, emergency services and City parks. 25. The applicant will be responsible for the improvement of the Park Avenue frontage. 26. The development of a private or public roadway along the north property line will have a much different impact on the adjoining lot than a driveway serving a single family home. Depending on the ultimate development pattern, instead of approximately 10 trips per day, there could be up to 60 or 70 trips per day. CONCLUSIONS: 1. In the main, a proposal to subdivide the subject site appears to serve the public use and interest. It appears that the most reasonable development of the subject site would be as a six-lot short plat. This would meet the density demands of the code without taxing the surrounding properties. It would also be an appropriate planning solution. 2. The proposed Option B was rejected by most parties including the applicant and staff as a convoluted plan. It would create double-fronted lots that deprive the affected home of any real privacy. It would also reduce substantially the useable lot area creating more pavement than useful yard. 3. Any public road would carve additional property from the remaining parcels. It does not appear practical and is unnecessary to achieve a density that is not needed by code. 4. The plat provides for lots that are somewhat larger than the 4,500 minimum thereby providing lots for those who want somewhat larger parcels. 5. The parcels are rectangular with lots lines at right angles to the street. The tots all comply with the requirements of the Zoning Code for the R-8 zone. 6. The slightly larger lots provide a good transition to the existing development patterns. The lots are compatible with the Comprehensive Plan. 7. The additional lots and resulting new homes actually should not adversely impact the City's services. The mitigation fees will help offset what impacts there are on the roads, parks and fire services. Development of the site increases the tax base of the City. Robert West Appeal and Short Plat Hearings File Nos.: LUA00-009, AAD LUA99-183, ShPI-H February 14, 2000 Page 13 8. The use of the easement and pipestem by five homes could have an adverse impact on the adjoining single family home. Therefore, the roadway shall be located as far as possible from the neighboring property and the non-road area shall be landscaped and fencing be erected to screen the adjoining parcel. 9. Since no plat design was submitted for a reduced lot count, the applicant may redesign the plat by either widening the lots of the east to west tier of lots or removing the stacked lots at the eastern edge of the plat. The design shall be reviewed by staff and its review submitted back to the Hearing Examiner for review and approval. The applicant shall resubmit its design in an expeditious manner but not later than 2 months from the date of decision. 10. In conclusion, the proposed plat appears to meet standards, will add to the tax base of the City and will not unduly burden City systems. DECISION: The Short Plat is approved subject to the following conditions: 1. The applicant shall demolish the existing house, garage and barn prior to recording the short plat. The applicant shall provide proof of the final demolition permit approval prior to the recording of the short plat. 2. The applicant shall provide landscaping between the private street and the north property line to ameliorate impacts of the private street on adjacent residents to the north. The landscaping shall be a minimum width of five feet. Maintenance of the landscaping shall be included in the homeowners agreement for maintenance of the private street. 3. Applicant shall pay a fire mitigation fee equal to $488 per new single family lot, payable prior to recording the short plat. 4. The applicant shall pay a parks mitigation fee of$530.76 per new single family lot, payable prior to recording the short plat. 5. The applicant shall pay a traffic mitigation fee of$75 per new average daily trip generated by the project. The proposal is expected to generate 9.55 average daily trips per new single family residential lot. The traffic mitigation fee shall be payable prior to recording the short plat. 6. The applicant shall create a homeowners association or maintenance agreement to maintain the private street and other common improvements on the site. 7. The applicant shall resubmit its design in an expeditious manner but not later than 2 months from the date of decision. The design shall be reviewed by staff and its review submitted back to the Hearing Examiner for review and approval. Robert West •Appeal and Short Plat Hearings File Nos.: LUA00-009, AAD LUA99-183, ShPI-H February 14, 2000 Page 14 ORDERED THIS 14th day of February, 2000. FRED J. KAUF N HEARING EXAX41NER TRANSMITTED THIS 14th day of February, 2000 to the parties of record: Robert West Peter Rosen David Casey 2903 Powerhouse Road 1055 S Grady Way 15 S Grady Way, 4400 Yakima, WA 98902 Renton, WA 98055 Renton, WA 98055 Christopher Brown Sam Robbins Olga Lissman 9688 Rainier Avenue S 3900 Park Avenue N 3930 Park Avenue N Seattle, WA 98188 Renton, WA 98056 Renton, WA 98056 Neil Watts Matt Pool Cyrus McNeely 1055 S Grady Way 12203 62nd Avenue E 3810 Park Avenue N Renton, WA 98055 Puyallup, WA 98373 Renton, WA 98056 TRANSMITTED THIS 14th day of February, 2000 to the following: Mayor Jesse Tanner Gregg Zimmerman, Plan/B1dg1PW Admin. Members, Renton Planning Commission Jana Hanson, Development Services Director Chuck Duffy, Fire Marshal Lawrence J. Warren, City Attorney Larry Meckling, Building Official Transportation Systems Division Jay Covington, Chief Administrative Officer Utilities System Division Councilperson Kathy Keolker-Wheeler Sue Carlson, Econ. Dev. Administrator South County Journal Betty Nokes, Economic Dev. Director Pursuant to Title IV, Chapter 8, Section 15 of the City's Code, request for reconsideration must be filed in writing on or before 5:00 p.m..February 28, 2000 Any aggrieved person feeling that the decision of the Examiner is ambiguous or based on erroneous procedure, errors of law or fact, error in judgment, or the discovery of new evidence which could not be reasonably available at the prior hearing may make a written request for a review by the Examiner within fourteen (14) days from the date of the Examiner's decision. This request shall set forth the specific ambiguities or errors discovered by such appellant, and the Examiner may, after review of the record, take further action as he deems proper. An appeal to the City Council is governed by Title IV, Chapter 8, Section 16, which requires that such appeal be filed with the City Clerk, accompanying a filing fee of$75.00 and meeting other specified requirements. Copies of this ordinance are available for inspection or purchase in the Finance Department, first floor of City Hall. Robert West Appeal and Short Plat Hearings File Nos.: LUA00-009, AAD LUA99-183, ShPl-H February 14, 2000 Page 15 If the Examiner's Recommendation or Decision contains the requirement for Restrictive Covenants, the executed Covenants will be required prior to approval by City Council or final processing of the file. You may contact this office for information on formatting covenants. The Appearance of Fairness Doctrine provides that no ex parte (private one-on-one) communications may occur concerning pending land use decisions. This means that parties to a land use decision may not communicate in private with any decision-maker concerning the proposal. Decision-makers in the land use process include both the Hearing Examiner and members of the City Council. All communications concerning the proposal must be made in public. This public communication permits all interested parties to know the contents of the communication and would allow them to openly rebut the evidence. Any violation of this doctrine would result in the invalidation of the request by the Court. The Doctrine applies not only to the initial public hearing but to all Requests for Reconsideration as well as Appeals to the City Council. q,57 W W%z32-24-5 RENTON rOrE RN Nfq rf rpnpra Ra eQRpM RSvq 1 rtl Fetl EurM iM r.voatabr..4r.na.ur ;V!w` aM w ro.rrq�.•vru.a v rro•w � .. , t� ------------------_.:*.-- -- ��-44TH--3T4 •—` E- —44TH T r Gov't Lot I 4290 Acr s 5\•\P Q ; { 4 �. � a y W N cr e - t v/ Y 1 N. ~ •� y C eorbee u.0 Ca II^y! Von !bade I.r.T/1:200" •tse 1! . Clerifaa Fo.cerr c Q _0: w I !r•AYE14 �y S T P 0 ao,� i, !I-R E Raberr A. gib' � am - -- r• �, ,;�/ tr :�E�I c✓ �`.�CJ1y C.Fred hoeffer 41 ? opti s N. 40TH ��• • $ z a Q ov't. Lot 2 e9 32.00 Acres=' r`� �� : �r - _ P r� 2y 88 �'t txt tst t t. 109 ®r a SITE a� a I no p1'— fir\? ... 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IlP 6 0C• (ACCESS EASEMENT) s•cowKuo arw 14f i u w([)-razes f___T = a 5.5e7s su 115.65 ' ( SOIID LOCIIwG�11D) I P.w C-120.91 ' N.15, 5IA 1.00 5'LTN[ K our 56'(w)-11.:77 A 11-17061 , SCALE: �1"=20• HORIZ IE w 17•(p-uc.v isyy If w 56'(E)-114 77 Irvra n utr,rox i arox6 .•id4i aervr rur' If OUT u-(W)-11..77 ;1"=2' VERT uaoo 1.00 7.00 3.00 f- - 1 4.00 5.00 ACCESS EASEMENT PROFILEJ5-1 r PR rW-1I6 e7 CV PN 1-[ 50[ . .' �12 10505..0r0 L[a Lw[-[ 5_Tt———————— PROP05[D DETENno"TANK I 'JF({r�tl S 1 r' IC 6'Our M)105 50 fEQ Syr=c_�r 1]0•-Ce-CYP_ �.ry ro x PI sso • I 0 dNI sl.1.sr.. ( .•�.�� tuf n.c SIDxN 1 _ . - 12 IIYf 1 Cun 1 TSPE 6-N• +Pawl[aI v-u+4 —� i-u1l/7 11 6-Ce' .•1'1i ' �4 PNOP.N ECP rl'�• CE17 TYPE 1 �t [LSTA•.aRR LOCA1NAr 0.. - _�♦ 1 ' � `5 rl � `Fr __ „_�_y 1 • � PROP.S \1J., + � — �I •(71,(�4n P OSED PROPOSED 26'ACCESS E•S'u'1 [R WATER UETCR� I ("SEWER STUB i --TER yE ff ' 1 ,A,, ( ) � 1 (0yjrp.r•7'arN 1 CMIOuA 1tef llrt Gw( PROPOSED e u+1Y([. >7] li}RTARY 51 R 4 7 r C✓/w(e. .. I / PNOPOS A1CR SERlwE 10 5[NvE VAL S Ir�A IUAL 51!( 10 CR1711P'CP .11 nI nl nnun 1n n�ulr / INnnw sx n INrarRrrruP1 / t■r is imi Fog Lwf-.WE r S ♦ .t �CASu rINGINNIFRING NIGH POINT DKVSWPYEM; WC 1�Y II�6. - r•Do • J. .: � GRAPHIC 9CAlt A♦ 4 .rirw xN �� (.AAI�- I.oa ro.u.a�6-.6>-t� .. ruD1 ,:� y C[TY OP PENT ON TERf PLACE SHORT PLAT �tP H {`t Iuw w'• �i�oiii•L`c�•1r 17EI No. r/77L77'PLAN t IMLls PROPRl ,`ii`rR{{bI •�� Iv.W6�u-a --ousn 1.70' '--5ra Pk x" r,.,4t ` - EXIST EDGE OF P 'T-E. SIDE OPTION I 11' - - - - - - - - - - EXIST FOG LINE.-I TIDE _ — — — I 0, EXISTING P.P. TO BE RELOCATED ' 55' PROP. N. EOP 0 i y ti� f I I PROP. S. EOP\ 26'.ACCE5$F'S'M'T I-- — — — --- I 26 I 2 3 L-i - - - - - - -j L _ - - - J L _ I I 7 T r 20' ACCESS E'S'M T OFF—SITE EXIST I 11 EXISTING P.P. I GARAGE TO REMAIN 12.3' S. OF.PL - I (6) 'Vp\�O�wf �i TS SOUfH CCASEY I GRAPHIC SCALE •t RENTON, WA aeon r :� CITY OF RENT I lush — 20 (L ;ysyt: FILE No. LUA- EXPIRES 5-13-01 n•w w„u wrn 1 TERI PLACE TECHNICAL INFORMATION REPORT SECTION III LEVEL I OFF-SITE ANALYSIS TABLE OF CONTENTS TASK 1: STUDY AREA DEFINITION AND MAPS TASK 2: RESOURCE REVIEW TASK 3: FIELD INSPECTION TASK 4: DRAINAGE SYSTEM DESCRIPTION AND PROBLEM SCREENING TASK 5: MITIGATION ` TASK 1: STUDY AREA DEFINITION The Teri Place property is within a portion of the Northwest quarter, of Section 32, Township 24 North, Range 5 East, Willamette Meridian, King County Washington. The site is located on the East side of Park Avenue N. approximately midway between North 381' Street and North 401" Street. The Teri Place property consists of 1.02 acres. There is an existing residence and three associated structures within the site—all of which are to be removed. There are two existing trees within the site. The remainder of the site is covered with pasture grass. The existing ground has slopes ranging from generally flat (eastern side of the site)to 6% in the vicinity of proposed lots 2 and 3. In the existing condition surface stormwater runoff, generally flows from the south to the north. There appears to be some off-site water entering the site from the south. Stormwater runoff from the site and the associated basin flows into Lake Washington that is not identified as a Critical Basin. The King County Sensitive Areas Folio (Wetlands and Streams) shows the site as being within the East Lake Washington drainage basin. The Upstream Study area extended south to North 38 h Street. The Downstream Study area extended downstream to Lake Washington. It is proposed to develop the property into a 6 single family residential dwelling units. A copy of the Thomas Brothers—page 627, with the subject site indicated, vicinity map is included in Section I of this Report. TASK 2: RESOURCE REVIEW The following resources have been reviewed in the preparation of this Downstream Analysis: 1. King County Basin Reconnaissance Summary Reports The site is within the East Lake Washington drainage Basin. A request has been made to King County for information on the East Lake Washington Drainage Basin. The information has not been received. 2. Flood plain/ floodway(FEMAI Map The site is not within a 100-yr floodplain. 3. Sensitive Areas Folio A copy of the Wetlands (Sheet 4) of the Sensitive areas Folio showing the location of the site, and the drainage basin the site is within, is included within this section. When King County mapped sensitive areas within the County, the sensitive areas within incorporated Cities were not included. Therefore, there is no reason to include all of the other sheets in the Sensitive Areas Folio. It should be noted that the basin boundary shown on Sheet 4 is in error as the boundary shows the site being within the May Creek Basin Boundary. The field investigation and the City of Renton Storm Drainage and Topography Maps indicate that the site is within a basin that drains directly into Lake Washington at a location different from the May Creek Confluence. 4. Drainage Investigation Information King County does not have any Drainage Investigation Information for the Study Area within the City of Renton. City of Renton Staff were not contacted prior to the preparation of this report due to the small size of the project (1.02ac) 5. King County Soils Survey Maps A copy of a portion of Sheet 5 of the King County Soils Survey Map is provided in Section I of this Report. The site is underlain with Indianola(InC) soils. 6. Wetlands Inventory Maps The King County Inventoried wetland page in the Folio does not include wetlands within the City. A site visit to the property did not indicate that there were wetlands within the site. 'I .1 i 1,��,�S16j1 �41 •��1. 1�;.I� \ - ._.'-~t1. •>' r �' � ( I '• I d ,a I I 11 f I.� •�l .. �/ sl'r� "{ �:f(I[f' // "�� - j -•--.�� _.�<•J ' f �J'� ,r', 1 �) ' � � 1. � Y; Lo l dd �l f f ,;r _ �f.� � - I,,?li•t I i-'"E_\p. t�,r r•Z i- V.•�•pp i _ .-'t:;.\ � r E , �I 'I(1 .J j �-t.- I�`• .f� .[ > �� /.(JJ.I�Jj r� t i. 'j�.. 1�i✓ 1111 ��'�-._ 1. C7 _,( ^ r� 'f � 1' I' _I J` i i •�.I ,".. 1 11 ,�. . l Y 111 ` ll 1 ':'_.r• .�.x•) l•� t I� l I T. � a� (' � i,{- ,,. la IL. , ` , I ,;J Ir li.�,r ..._._ ',_t•.. �<i-111 � .:fit. rl_ .Jl,ai � _ _.�i_ ,o2i •'Lr -- 1 •., mil. i(__t I f'_ 1 � J 1 _ J( 1+ �,.�.l fi:' ,. ,� r - � ' � ..11 1' f'-4�.: ,� . � `� ��Y S•�lr �(,z= �` ( 7,1 ,�. .•i.l . . . �:= � ,:j� r r 1 �I 'NI �'y� �♦" 9\ F'I 1' I1 1 I C. 1 r l'}'r r- o ,.� d > ,L_�Fi -,Q -�.. -� : 'c. 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ITT': �_tl1+� >t ((•q�'. *-,'',r r��,� { .,� - r .. __L>^ 1_l•r r ',,1 JP _ •I{}�vR Y.� ' '. { fap.i. y �: .....--.. .:. ._ r �-. i t•. •-� �''a-_y � �a,0 a•a �'>v M-t(!R«. ny I ��. .L *,•(, :.%F �+ -' ,24,, 't��."t _�. I� � ;-/� � t l� ^"��_s::- ^�� -1__ ,� �--I-_ h D io C>u i,°_ ,• �(t"��!i-.:'�t'g4`: 'f.'j��I: •-C� •� }_. 9 ��* �� I � [--I-,<tlfs� �( ��• � f1 -- a,..._..�,T^ __r• ) �-I' _.�.%!*, __I III-•LPL �.E a,W��..�N Z ff _ '/Pr••' i I", g _-� �.'�.r"r.. 1 1 f. 'C.� � .`' .J •„�'.. _ - ri'F F• '.L'11 _ •r v I o t - --- ' a . . .� .i liels L II�.��.�„-`-'�^�'{'i1 .. .r ` r_d.. ....}�.'r' -,..- ,... I•--^fir..�`�X/'I-' '.I � - - �-__ '-- ^� t ,_ �y O.S st fi�� tl .�:.. {k.',-;,••.a 7 i ''"�' �;. 1 .�,:. }( ^c _ (I ,r''�('T�' �' m m Ll �1Cryw•7 I 9:.{ ir`.:. 41 ■.a` I.. y '•+,!1 ixl �� .F.: I {^ '�: l ;- �•1 1- / �' «:t- .- �V1- �• .� ,! I�i,t IC 1•••�� CG y • ♦ �i''.. l'' - - . �!.I gp�J :� '�' '^ ,;' •�,♦ � / � -� 1,. M'. vt t I I � / _ '""Nao °'^Eco 1� IA�l 1 `yJ "1 �y' `1, 1 -�_ _ �� _ N•.. �� -.I _ a -� �a•.d •- Iff �'\.•} _� i j, t V�D ar «, I_ ,�f,.«R a�T - - ` 4,rll °u=FA3a;a.0ar �i: ; 1 -4 F �....� �-J+ M•'.: -_ _ 1 1 _sF I �1 ry[ / `I •x.'J��1 '� •y f �� fJ it C ( C •�'.N t --l1f,oI -°moo UJI 1.11111. A% * N • I TASK 3: FIELD INSPECTION The Teri Place property has been field surveyed. Topographic contours at 1' intervals are shown on the engineering plans. The 5' contours are shown as extending beyond the property. The site and the observable downstream system to the outfall at Lake Washington, located within the Barbie Mill property, was most recently visited on December, 19, 1999. The weather during the site visit was overcast and rainy. It has been raining quite heavily in the past several days. Stormwater was observed to be flowing within all of the drainage features observed. 1 Investigation of Reported or Observed Problems During Resource Review None of the resources reviewed at the time this downstream analysis was prepared indicated that there are any ongoing problems with the downstream system from the site downstream to the outfall at Lake Washington. 2 Location of Existing/Potential Constrictions or Lack of Capacity in the Existing Drainage System The existing conveyance on the East side of Park Avenue North, adjacent to the Teri Place site is 8" CMP. The inlet of the 8"CMP is within a ditch. It is not known if this conveyance has existing capacity for the site, and the upstream basin that contributes stormwater runoff to it. This conveyance may need to be replaced with a 12" conveyance. This will be determined during the review of the design by the City of Renton. There is a short section of 24" CPEP within the Barbie Mill property that has a built up headwall at the inlet of the conveyance at the end of a ditch. This may indicate that there are capacity issues related to the conveyance within the Barbie Mill Property 3 Identification of Existing/Potential Flooding There were no indications of existing or potential flooding within the observed downstream system. It should be noted that the downstream system from the site to the West side of the railroad grade is tightlined and the conveyance slopes are generally fairly steep. 4 Identification of ExistingRotential Overtopping Scouring Bank Sloughing or Sedimentation All of the downstream components observed were in very good condition. The ditch within the Barbie Mill property was generally very stable. All of the observed conveyance systems appeared to be in good condition with minimal sediment accumulation. 5 Identification of Significant Destruction of Aquatic Habitat or Organisms The site is within an area that is urbanized and has experienced a gradual decline in the process. All of the historic upstream tributaries within the downstream system have been eliminated at some time in the past. 6 Collection of Qualitative Data on Land Use Impervious Surfaces Topography, and Soil Types The upstream contributing drainage basin that contributes stormwater runoff to the outfall at Lake Washington within the Barbie Mill Property is mostly developed into single family residences. The soil type for the majority of the basin is Indianola(InC). The topography of the site is shown on the engineering plans. A copy of the City of Renton Aerial topography map is provided in the appendix of this subsection. A Copy of the City of Renton Storm Drainage facilities map for the w '/2 of S5-T23N-R5E was obtained and used in the preparation of this report. A copy is provided at the end of this Section. Components of the downstream system from the site to the outfall location at Lake Washington are provided in Task 4 of this Section. 7 Collection of Information on Pipe Sizes Channel Characteristics, and Drainage Structures. Field survey information of the existing conveyance system along the East side of Park Ave N. to the intersection at North 40th Street is provided on the Preliminary Short Plat map. Drainage information from the Type II structure along Lake Washington Blvd to the outfall at Lake Washington was obtained from visual observation and a 25' tape to measure pipe sizes. 8. Verification of Tributary Basins The tributary basin of the site is based upon walking the site. The tributary basin contributing runoff to the outfall at Lake Washington was verified by field observation of basin breaks along roads and documentation obtained from the City of Renton. 9. Contactingof f Neighboring Property Owners No neighbors were contacted during the preparation of this downstream analysis. 10 Documentation of Existing Site Conditions The existing site conditions are documented in this report by walking the site. 11. Collection of Quantitative Field Data The quantitative field data collected for the site and downstream to the outfall at Lake Washington consists of field topography and field measurements of culverts using a 25' tape. Distances were measured using the City of Renton Aerial topography map at 1"=200' TASK 4: DRAINAGE SYSTEM DESCRIPTION AND PROBLEM SCREENING 1. Drainage System Components The Following is a Narrative of the downstream system from the Teri Place Site to the 24" CPEP outfall at Lake Washington within the Barbie Mill property. a. Existing Condition: In the existing condition, there is no defined downstream flowpath for stormwater leaving the site. The majority of the stormwater that leaves the site appears to sheet flow through the properties to the north where it is intercepted by the curb flow on the south side of North 40'h Street. A small portion of the site drains to the west where it is intercepted by the curb flow on the East side of Park Avenue N. All of the stormwater that leaves the site converges at a Type II storm manhole structure at the intersection of Park Ave N. and N 40`h St. Stormwater leaving the Type II structure at the intersection of Park Ave N. and N 401h St. flows to the west down N 40`h St in a tightlined conveyance system to Lake Washington Blvd. The conveyance system then directs stormwater to the north for a short distance to a Type H structure on the west side of Lake Washington Blvd. Stormwater leaving this structure is directed to the west into a Type II structure on the east side of the railroad grade. This system is shown on the copy of the City of Renton Stormwater Facility map provided in this section. The outlet pipe from the Type II structure between Lake Washington Blvd. And the rail road grade directs stormwater to the west under the railroad grade where it outlets into a ditch within the Barbie Mill property. The ditch is approximately 2' deep, 1' wide at the bottom with side slopes of approximately 2:1. The ditch flows to the west for a short distance where it enters a 24" CPEP conveyance system. This conveyance system flows a short distance to the southwest to a shallow Type II structure. Stormwater leaving this structure is directed to an outfall adjacent to Lake Washington located to the west of a dock. b. Proposed Developed Condition In the developed condition, stormwater will be collected within an on-site conveyance system and directed into an underground detention facility proposed to be located within the access easement along the north side of the Teri Place property. Stormwater leaving the detention tank is proposed to be conveyed in a piped system to the west to tie into the existing conveyance system on the east side of Park Avenue N. Stormwater will flow to the north and follow the route described in part "a." above. 2. Existing/Potential Problems The most obvious existing/potential problem relates to the existing 8" CMP conveyance along the East side of Park Ave N. It appears that the 8" CMP is connected to a 12" CMP prior to entering the Type I CB structure at the Park Ave. N./North 40t' St. intersection. This issue will be addressed during the engineering review and approval phase of the project. TASK 5: MITIGATION The size of the Teri Place site and the small difference between the existing condition 100yr-24 hr storm compared to the developed condition 100yr-24hr storm results in no detention requirements for the site. A water quality tank is proposed to provide mitigation for water quality. B4 - 29 T24N ME W •1/Z 1310-3 41 11/ clo- 1. I __ __ � r ' / � 11I i :•%.'�f2-�7fr'9 ;�Ir_2 I,HI L KE WASHGTON r �II,4 I 1 w 1 SO 1 3.04 s• � 1�l '1 / 11 1' 1r�!� r 7, f r —, 1 _'''Xppp- • r r �q�. 1.l - +.,�i +e'!'-1 r ! 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C �'� �,; ,1! /• I I ' y Ail t r: -3 l 1 ) _ - 1 i � .I to 1.1 r !. r l I I • ;1 I ,, 1 /11 1 / /-., / / ]C ly �• - '', �� /' 'I. � ' i r / / r! % \ r .d II III _ 'rI{T K 1/6ll •\ � \ � 1 i II 1 I .L-.\1t t ♦..'--% 7-7_ 1 I I ,r. � ( / / ;( /,• � y1 I'.III I J.I t _�. `� , ,>\ � . 2• _ w_6], a St S C - \ I,i /• i. -" DB-IB. ' -'], _ .•,� \• •,.� \ \<, •� 1 ] CD t 00-1E• � ' � ` ` \1 \y `. \ ( lW-] /]�_ �� . i I •)� feat•'::.. 8-8 \\.` '\t � ',1`s. I 1 � ,,� ' �! I l\l 1 t I � � -'; ,il II•I I ') \ 2 ��.�t- s. 8 \ ?.De- A 1VN `�\,\,\\ \. 7.C8 ' �r��'Z<y-i', /r / .\' I I i j - f2-6 - \ .\..,,,♦ -�s.- r.fi Kf furl 1 I '\ JC. ,t II; \ D4 - 5 T23N ME W 1/2 Goo Y UTILITIES DIVISION ---- Renton City Limits 4 1.4800 {40 P/H/PW TECBNICAL SERVICES Como= latwvab M or LA auan C4 �N�o 04/06/% >� »VD IM >� 32 T24N ME W 1/2 O fI XIIt I I l l II If • , t \ 1\ � �(��11 I I I �I III'\,,, � }\\\\\\•`\ ` 1.1 _. k x x , / /�/. —_ —._.__. 1 1 1 1 / � x _ 8 '1 d � x x„ QX 3 , e 1 \ - x c-� 9LJ1 1 k d lol it ' TII X x , - •kA x\\ _ t f ♦ � 1 I I I I I I I I I I TERI PLACE TECHNICAL INFORMATION REPORT SECTION IV DETENTION FACILITY ANALYSIS AND DESIGN Provided in this section is the following information: A. Existing Condition& Creation of Existing Condition Hydrographs B. Developed Condition& Creation of Developed Condition Hydrographs C. Detention Discussion D. Water Quality Tank Sizing Information EXHIBIT 1: EXISTING CONDITION EXHIBIT o TERI PLACE - STORM DESIGN SECTION W.A. Information Used in Creation of Existing Condition Hydrographs Pre-Developed Condition- Hydrographs Information is provided concerning the creation of the pre-developed condition hydrographs for the 2yr-24hr, and l0yr-24hr storms. The Waterworks Basin Summary printout for the existing condition hydrographs are included in this section. The Existing condition Tc flowpath is shown on the EXISTING CONDITION EXHIBIT provided in this sub-section. Copies of tables referenced in this section are provided in the Appendix of this report. /. /-7rco = v� �✓ S� /%s/c - %o/-c 912-Lots-Z117e L i sf �iroahQ/ �`/7G �ori�c�nry o� 1`/1c Siff 02 o c —,q rcci 7- 7 = 2 , So./s = The �,�9 CGUrJ/ .Soi/S /yJ <shCCf ' Zr7 c�a,9 o% l�vi f�7 .Scrips v LO ° &S Z A o .m zw Group� Soi/s 3, C/1/ (/o/vas The C'/� h%vPs uscd �� fhc e��sf��y /s- C/17,ocr� ; C�Qsfv�C� _ 6 S- Grovel /` O ocl — 7:� EXisf.l noCrjl z Gor a9C@ C/SX�o� = USO LO-P L120 YZo) � = 2/ /00�f7 EX�Sf �e ry f�rsq = A ToT — I"1l-,-7 ry I Teri' /pcc T/, Sccf 3. Gravc/ good/'�� Q = biz.YIzo) - 0 3 oc� Cw- 7G C//= 6S` m Cl. 0 a v `� �rcc�;0/ Tn fi'olJ = C,o/cs a�ISa/o/vvi4/J /� /9ya� X cn � ti 0 0 31 iz.s - 1z 0 = s s, = 3 7 90 L /S o12 T, 117c- 2 /� C4/Ct�/ofc� vs.i�9 l�vG7Le/wG�"/cs T 3- �G�GrGr/o��s �p1r/:��-ova o� EXis� Co/7071 ,asl;12 SCi/YJ/Ylli�'y ShCG/S TOE LJ �O� ��OO y� S�O/�/�JJ' z 0.42 L 12/17/99 5 :31:30 pm Casey Engineering page 1 TERI PLACE EXISTING CONDITION BASIN SUMMARY BASIN ID: EXIST02 NAME : EXIST. COND. 2yr-24hr STORM SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 . 02 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : KC24HR PERV IMP PRECIPITATION. . . . : 2 . 00 inches AREA. . : 0 . 96 Acres 0 .06 Acres TIME INTERVAL. . . . : 10 .00 min CN. . . . : 65 .30 98 . 00 TC. . . . : 12 .32 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Sheet L: 135 . 00 ns : 0 . 1500 p2yr: 2 . 00 s:0 . 0370 PEAK RATE: 0 . 03 cfs VOL: 0 . 02 Ac-ft TIME: 470 min BASIN ID: EXIST10 NAME: EXIST. COND. 10yr-24hr STORM SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 . 02 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : KC24HR PERV IMP PRECIPITATION. . . . : 2 . 90 inches AREA. . : 0 . 96 Acres 0 . 06 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 65 .30 98 .00 TC. . . . . 12 .32 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Sheet L: 135 . 00 ns : 0 . 1500 p2yr: 2 . 00 s :0 . 0370 PEAK RATE: 0 . 06 cfs VOL: 0 . 05 Ac-ft TIME: 480 min BASIN ID: EXIST100 NAME: EXIST. COND. 100yr-24hr STORM SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1. 02 Acres BASEFLOWS : 0 .00 cfs RAINFALL TYPE. . . . : KC24HR PERV IMP PRECIPITATION. . . . : 3 . 90 inches AREA. . : 0 . 96 Acres 0 . 06 Acres TIME INTERVAL. . . . : 10 .00 min CN. . . . : 65 .30 98 . 00 TC. . . . . 12 .32 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Shee L: 135 .00 ns : 0 .1500 p2yr: 2 . 00 s :0 .0370 PEAK RATE: 0 1 cfs VOL: 0 .10 Ac-ft TIME: 480 min W. SURF 96.42 DRAIN • RIM- 101.04 EXiSTi /I� Co a�i 7�i"o�J IE 12" CONIC. IN (NE) 98.89 — — / 2'�/ / IE 12" CONC. IN (S) 98.89 E-�9"6PEf�AN��A1��8.19 NORTH 40TH STREET (S.[:-- 84TH ST. ! I I I I I! TRACT I 107 S I I DOSING STORM CONIC. PIPE ( 111 ) (2) ! �R I EX WATER METERS ( ) I I TRACT 2 201 11' I� EXIST D OF PVM'T-E, SIDE ! O5 I EXIST FOG LINE-E. SID EXISTING P.P.,';n TO BE RELOCATED , =GARAGE N88'54'30"W 427.54 \\/� EXISTING 8' STORM CMP PIPE IE-115.3 — EXIST EXISTING DITCH - GARAGE / EXISTING 6' WATER j rri >X LINE -. EXIST 12; DRIVE y _ 5- 1zs-12-01 =s 0 3 EX WATER METER / /—L 51 GEXSTNGRADE COTOUR 5-�Qh 0'\�� r-- EXISTING 8" STORM �\ Li Ln CMP PIPE IE-117.22 EXISTING 8" L J / CMP PIPE IE-118.44 i EXISTING DITCH EX 8" S.S. � `� ' i i� ��_ - � r XIST EDGE OF PVM'T-W. SI �:� - � `�� Z OFF-SITE EXIST N88*51 '30"W q.27�90 EXIST FOG LINE-W. SIDE 1 11 �_ GARAGE - EXISTINC P.P. TO REMAIN 2.3' S. 0 (6) ST • P�J ��( I PO � TRA -C i 04 r�AoR , �� TERI PLACE - STORM DESIGN SECTION W.B. Information Used in Creation of Developed Condition Hydrographs Developed Condition- Hydrographs Information is provided concerning the creation of the developed condition hydrographs for the site. The Waterworks Basin Summary printout for the 2, 10, and 100yr-24hr developed condition hydrographs are included in this sub-section. The site is not within a "critical basin". During the preparation of the Level I Downstream analysis, there were no identified downstream capacity or flooding issues. Copies of tables referenced in this section are provided in the Appendix. r c%s,y�� offheCoro/"c��` nssa�ncs icy/�of/ 012 �p/mac os G:�iS�i's�� _ / aZ o c < /-4 jof' /� v 0 A 0 3, C/l� j/o%c s = (�s i�9 Tab/c 3,S,0 U L ti o m Lo 0 LO .s zw yoo d Co�G�i'��00 C/'✓L,n�Iry = 1 � �-- C/�/I/� �/' /"i'cc�,p��af�0/I .' SG/7jC �S ��is1ii?9 �orC�iTiO/J �vG fo ��c S/7�9/� Size 07C f�7G SifCJ 7hG UOoW C/I,7ii>e��,�/�' T�cw TG 1/yi�c/v = .�I�ii7 � �G �rn�pery SG �<iry 14 = lz�To T — 141lvc1 v = /OZ C,G - --� Iri//oTc�vt/or/s�ri�fo�>` cif ,De✓ Comic✓ �s�h 5��,o�y , 4/14/00 12 :45 :11 am Casey Engineering page 1 TERI PLACE DEVELOPED CONDITION BASIN SUMMARY BASIN ID: DEV002 NAME : DEV. COND. 2yr-24hr STORM SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 . 02 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : KC24HR PERV IMP PRECIPITATION. . . . : 2 .00 inches AREA. . : 0 .49 Acres 0 .53 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 68 . 00 98 . 00 TC. . . . . 10 . 00 min 5 .00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 0 .27 cfs VOL: 0 . 09 Ac-ft TIME: 470 min BASIN ID: DEV010 NAME: DEV. COND. 10yr-24hr STORM SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 . 02 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : KC24HR PERV IMP PRECIPITATION. . . . : 2 . 90 inches AREA. . : 0 .49 Acres 0 .53 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 68 . 00 98 . 00 TC. . . . . 10 . 00 min 5 .00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 0 .41 cfs VOL: 0 . 14 Ac-ft TIME: 470 min BASIN ID: DEV100 NAME: DEV. COND. 100yr-24hr STORM SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 . 02 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : KC24HR PERV IMP PRECIPITATION. . . . : 3 . 00 inches AREA. . : 0 .49 Acres 0 .53 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 68 . 00 98 . 00 TC. . . . . 10 . 00 min 5 .00 min ABSTRACTION COEFF: 0 . 20 PEAK RATE : 0 .43 cfs VOL: 0 . 15 Ac-ft TIME: 470 min //��1� G� L1Q z 0,C. o. �g : �.�1 �FSL 0.S-Cjr Q �(a �J^_ V� TERI PLACE - STORM DESIGN SECTION IV.C. Detention Discussion: The following is a comparison between the Existing Condition 100yr-24hr runoff from the site compared to the Developed Condition 100yr-24hr runoff from the site. 1. Existing Condition 100yr-24hr runoff: From Section IV.A Hydrograph Summary, the existing condition 100yr-24hr runoff from the site is: .19cfs 2. Developed Condition 100yr-24hr runoff: From Section IV.B Hydrograph Summary, the developed condition 100yr-24hr runoff from the site is: .43cfs 3. Difference Between Existing and Developed in a 100yr-24hr storm is: .24cfs < .50cfs Therefore onsite detention is not required for the project. ,y. mil/ Q'f er Qvo�7�y si��i�q 70 w,r��9 ✓,��ch l�i�� Sed f Cl Ile r -cif' � 3 14 1 1;��erg G4 = .5.� oc /7/Gc1 //7c vv�fer .9v�/'y l/a/vac ,s d•�`��,%��.:/ USi i�� L/a fC✓�ivor/1-- Sc C Q f��rchc� Vo11 a S'frvc vrcr %oe L 1767 i 4/14/00 4 :43 :36 pm Casey Engineering page 1 TERI PLACE DEVELOPED CONDITION BASIN SUMMARY BASIN ID: WATQUAL NAME: WATER QUALITY VOLUME CALCS . SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 .53 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : KC24HR PERV IMP PRECIPITATION. . . . : 0 . 67 inches AREA. . : 0 . 00 Acres 0 .53 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 0 . 00 98 .00 TC. . . . . 0 . 00 min 5 .00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 0 . 07 cfs VOL: 0 . 02 Ac-ft TIME: 470 min TERIPLACE TECHNICAL INFORMATION REPORT SECTION V CONVEYANCE SYSTEM ANALYSIS AND DESIGN Due to the small size of the site, no conveyance calculations have been performed. TERI PLACE TECHNICAL INFORMATION REPORT SECTION IX EROSION AND SEDIMENTATION CONTROL DESIGN Plan sheet 5 of the engineering plan set contains the Temporary Erosion and Sedimentation Control Plan (TESCP) and grading for the project. The basic features contained within the plan include the delineation of the clearing limits, silt fencing, and a Stabilized Construction Entrance. Due to the small size of the site it is not anticipated that there will be any sediment laden stormwater leaving the project. TERI PLACE TECHNICAL INFORMATION REPORT SECTION XI MAINTENANCE AND OPERATIONS MANUAL The storm drainage system within the Teri Place project is to be privately owned and maintained by the Homeowners Association. Provided in this section is the following information from the K.C.S.W.D.M.: No. 3 Closed Detention Systems (Pipes/Tanks)—Applies to the Water Quality Tank No. 5 Catch Basins No. 10 Conveyance Systems (Pipes &Ditches) KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL NO. 3 - CLOSED DETENTION SYSTEMS (PIPES/TANKS) Maintenance Conditions When Maintenance Results Expected Component Defect is Needed When Maintenance is Performed Storage Area Plugged Air Vents One-half of the cross section of a vent is Vents free of debris and sediment. blocked at any point with debris and sediment. Debris and Accumulated sediment depth exceeds All sediment and debris removed from Sediment 10%of the diameter of the storage area storage area. for 1/2 length of storage vault or any point depth exceeds 15% of diameter. Example: 72-inch storage tank would require cleaning when sediment reaches depth of 7 inches for more than 1/2 length of tank. Joints Between Any crack allowing material to be All joints between tank/pipe sections are Tank/Pipe Section transported into facility. sealed. Tank/Pipe Bent Any part of tank/pipe is bent out of shape Tank/pipe repaired or replaced to design. Out of Shape more than 10% of its design shape. Manhole Cover not in Place Cover is missing or only partially in place. Manhole is closed. Any open manhole requires maintenance. Locking Mechanism cannot be opened by one Mechanism opens with proper tools. Mechanism Not maintenance person with proper tools. Working Bolts into frame have less than 1/2 inch of thread (may not apply to self-locking lids). Cover Difficult to One maintenance person cannot remove Cover can be removed and reinstalled by Remove lid after applying 80 pounds of lift. Intent one maintenance person. is to keep cover from sealing off access to maintenance. Ladder Rungs King County Safety Office and/or Ladder meets design standards and Unsafe maintenance person judges that ladder is allows maintenance persons safe access. unsafe due to missing rungs, misalignment, rust, or cracks. Catch Basins See "Catch Basins" Standard No. 5 See "Catch Basins" Standard No. 5 A-3 1/90 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL NO. 5 - CATCH BASINS Maintenance Conditions When Maintenance Results Expected Component Defect Is Needed When Maintenance is Performed General Trash & Debris Trash or debris of more than 1/2 cubic No trash or debris located immediately in (Includes foot which is located immediately in front front of catch basin opening. Sediment) of the catch basin opening or is blocking capacity of basin by more than 10%. Trash or debris (in the basin) that No trash or debris in the catch basin. exceeds 1/3 the depth from the bottom of basin to invert of the lowest pipe into or out of the basin. Trash or debris in any inlet or outlet pipe Inlet and outlet pipes free of trash or blocking more than 1/3 of its height. debris. Dead animals or vegetation that could No dead animals or vegetation present generate odors that would cause within the catch basin. complaints or dangerous gases (e.g., methane). Deposits of garbage exceeding 1 cubic No condition present which would attract foot in volume. or support the breeding of insects or rodents. Structural Damage Corner of frame extends more than 3/4 Frame is even with curb. to Frame and/or inch past curb face into the street (if Top Slab applicable). Top slab has holes larger than 2 square Top slab is free of holes and cracks. inches or cracks wider than 1/4 inch (intent is to make sure all material is running into the basin). Frame not sitting flush on top slab, i.e., Frame is sitting flush on top slab. separation of more than 3/4 inch of the frame from the top slab. Cracks in Basin Cracks wider than 1/2 inch and longer Basin replaced or repaired to design Walls/Bottom than 3 feet, any evidence of soil particles standards. entering catch basin through cracks,or maintenance person judges that structure is unsound. Cracks wider than 1/2 inch and longer No cracks more than 1/4 inch wide at the than 1 foot at the joint of any inlet/outlet joint of inlet/outlet pipe. pipe or any evidence of soil particles entering catch basin through cracks. Settlement/ Basin has settled more than 1 inch or has Basin replaced or repaired to design Misalignment rotated more than 2 inches out of standards. alignment. Fire Hazard Presence of chemicals such as natural No flammable chemicals present. gas, oil, and gasoline. Vegetation Vegetation growing across and blocking No vegetation blocking opening to basin. more than 10% of the basin opening. Vegetation growing in inlet/outlet pipe No vegetation or root growth present. joints that is more than six inches tall and less than six inches apart. Pollution Nonflammable chemicals of more than No pollution present other than surface 1/2 cubic foot per three feet of basin film. length. A-5 1/90 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL NO. 5 - CATCH BASINS (Continued) Maintenance Conditions When Maintenance Results Expected Component Defect Is Needed When Maintenance Is Performed Catch Basin Cover Cover Not in Place Cover is missing or only partially in place. Catch basin cover is closed. Any open catch basin requires maintenance. Locking Mechanism cannot be opened by one Mechanism opens with proper tools. Mechanism Not maintenance person with proper tools. Working Bolts into frame have less than 1/2 inch of thread. Cover Difficult to Cne maintenance person cannot remove Cover can be removed by one Remove lid after applying 80 lbs. of lift; intent is maintenance person. keep cover from sealing off access to maintenance. Ladder Ladder Rungs Ladder is unsafe due to missing rungs, Ladder meets design standards and Unsafe misalignment, rust, cracks, or sharp allows maintenance person safe access. edges. Metal Grates Grate with opening wider than 7/8 inch. Grate openings meet design standards. (if applicable) Trash and Debris Trash and debris that is blocking more Grate free of trash and debris. than 20%of grate surface. Damaged or Grate missing or broken member(s) of Grate is in place and meets design Missing the grate. standards. A-6 1/90 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL NO. 10 - CONVEYANCE SYSTEMS (Pipes & Ditches) Maintenance CondMons When Maintenance Results Expected Component Defect is Needed When Maintenance is Performed Pipes Sediment& Debris Accumulated sediment that exceeds 20% Pipe cleaned of all sediment and debris. of the diameter of the pipe. Vegetation Vegetation that reduces free movement of All vegetation removed so water flows water through pipes. freely through pipes. Damaged Protective coating is damaged; rust is Pipe repaired or replaced. causing more than 50%deterioration to any part of pipe. Any dent that decreases the cross section Pipe repaired or replaced. area of pipe by more than 20%. Open Ditches Trash &Debris Trash and debris exceeds 1 cubic foot Trash and debris cleared from ditches. per 1,000 square feet of ditch and slopes. Sediment Accumulated sediment that exceeds 20% Ditch cleaned/flushed of all sediment and of the design depth. debris so that it matches design. Vegetation Vegetation that reduces free movement of Water flows freely through ditches, water through ditches. Erosion Damage to See "Ponds" Standard No. 1 See "Ponds' Standard No. 1 Slopes Rock Lining Out of Maintenance person can see native soil Replace rocks to design standard. Place or Missing (if beneath the rock lining. Applicable) Catch Basins See "Catch Basins" Standard No. 5 See "Catch Basins" Standard No. 5 Debris Barriers See "Debris Barriers" Standard No. 6 See"Debris Barriers" Standard No.6 (e.g., Trash Rack) A-11 1/90 r TERI PLACE TECHNICAL INFORMATION REPORT APPENDIX The following information is contained in this Appendix: A. Copy of King County SWM Manual Figure 3.5.2.A showing the soil and hydraulic group for the site. B. Copy of King County SWM Manual Table 3.5.2.B. showing the SCS runoff curve numbers used in the analysis. C. Copies of Isopluvial maps showing the 2yr-24hr, l0yr-24hr and 100yr-24hr precipitation at the site. D. Copy of King County SWM Manual Table 3.5.2.0 showing the "n" and"k" values used in the development of the time of concentrations for the hydrographs. KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL (2) CN values can be area weighted when they apply to pervious areas of similar CN's (within 20 CN points). However, high CN areas should not be combined with low CN areas (unless the low CN areas are less than 1 5% of the subbasin). In this case, separate hydrographs should be generated and summed to form one hydrograph. FIGURE 3.5 2A HYDROLOGIC SOIL GROUP OF THE SOILS IN KING COUNTY HYDROLOGIC HYDROLOGIC SOIL GROUP GROUP* SOIL GROUP GROUP* Alderwood C Orcas Peat D Arents, Alderwood Material C Oridia D Arents, Everett Material B Ovall C Beausite C Pilchuck C Bellingham D Puget D Briscot D Puyallup B Buckley D Ragnar B Coastal Beaches Variable Renton D Eadmont Silt Loam D Riverwash Variable Edgewick C Salal C Everett A/B °Sammamish D � Indianola A Seattle D 4'L Kitsap C Shacar D Klaus C Si Silt C Mixed Alluvial Land Variable Snohomish D Neilton A Sultan C Newberg B Tukwila D Nooksack C Urban Variable Normal Sandy Loam D Woodinville D HYDROLOGIC SOIL GROUP CLASSIFICATIONS A. (Low runoff potential). Soils having high infiltration rates, even when thoroughly wetted, and consisting chiefly of deep, well-to-excessively drained sands or gravels. These soils have a high rate of water transmission. B. (Moderately low runoff potential). Soils having moderate infiltration rates when thoroughly wetted, and consisting chiefly of moderately fine to moderately coarse textures. These soils have a moderate rate of water transmission. C. (Moderately high runoff potentiai). Soils having slow infiltration rates when thoroughly wetted, and consisting chiefly of soils with a layer that impedes downward movement of water, or soils with moderately fine to fine textures. These soils have a slow rate of water transmission. D. (High runoff potential). Soils having very slow infiltration rates when thoroughly wetted and consisting chiefly of clay soils with a high swelling potential, soils with a permanent high water table, soils with a hardpan or clay layer at or near the surface, and shallow soils over nearly impervious material. These soils have a very slow rate of water transmission. * From SCS, TR-55, Second Edition, June 19M, Exhibit A-1. Revisions made from SCS, Soil Interpretation Record, Form #5, September 1988. 3.5.2-2 11/92 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TABLE 3.5.213 SCS WESTERN WASHINGTON RUNOFF CURVE NUMBERS SCS WESTERN WASHINGTON RUNOFF CURVE NUMBERS (Published by SCS in 1982) Runoff curve numbers for selected agricultural, suburban and urban land use for Type 1A rainfall distribution, 24-hour storm duration. CURVE NUMBERS BY HYDROLOGIC SOIL GROUP LAND USE DESCRIPTION A B C D Cultivated land(1): winter condition 86 91 94 95 Mountain open areas: low growing brush and grasslands 74 82 89 92 Meadow or pasture: I 65 78 85 89 Wood or forest land: undisturbed or older second growth 42 64 76 81 Wood or forest land: young second growth or brush 55 72 81 86 Orchard: with cover crop 81 88 92 94 Open spaces, lawns, parks, golf courses, cemeteries, landscaping. good condition: grass cover on 75% or more of the area 68 80 86 90 fair condition: grass cover on 50% to 75% of the area 77 85 90 92 Gravel roads and parking lots 76 85 89 91 Dirt roads and parking lots 72 82 87 89 Impervious surfaces, pavement, rcofs, etc. 98 98 98 98 -- Open water bodies: lakes, wetlands, ponds, etc. I 100 100 100 100 Single Family Residential (2) Dwelling Unit/Gross Acre % Impervious (3) 1.0 DU/GA 15 Separate curve number 1.5 DU/GA 20 shall be selected 2.0 DU/GA 25 for pervious and 2.5 DU/GA 30 impervious portion 3.0 DU/GA 34 of the site or basin 3.5 DU/GA 38 4.0 DU/GA 42 4.5 DU/GA 46 5.0 DU/GA 48 5.5 DU/GA 50 6.0 DU/GA 52 6.5 DU/GA 54 7.0 DU/GA 56 Planned unit developments, 46 impervious condominiums, apartments, must be computed commercial business and industrial areas. (1) For a more detailed description of agricultural land use curve numbers refer to National Engineering Handbook, Section 4, Hydrology, Chapter 9, August 1972. (2) Assumes roof and driveway runoff is directed into street/storm system. (3) The remaining pervious areas (lawn) are considered to be in good condition for these curve numbers. �� 3.5.2-3 11/92 • WRIP. �N sm r PROVE� ASK f �slox ��I Ili n� pr � � r DF411 s � � kill IMF MW rim IL w _ " �( ►� , C KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TABLE 3.5.2C "n" AND "k" VALUES USED IN TIME CALCULATIONS FOR HYDROGRAPHS -n.-Sheet Flow Equation Manning's Values(For the Initial 300 ft of travel) n,• Smooth surfaces(concrete,asphalt,gravel,or bare hard packed soil) 0.011 Fallow fields or loose sod surface(no residue) 0.05 Cultivated sod with residue cover(s <.0.20 ft/ft) 0.06 Cultivated soil with residue cover(S>0.20 ft/ft) 0.17 Short prairie grass and lawns 0,15 Dense grasses 0.24 Bermuda grass 0.41 Range(natural) 0.13 Woods or forest with light underbrush 0.40 Woods or forest with dense underbrush 0.80 *Manning values for sheet flow only,from Overton and Meadows 1976(See TR-55, 1986) "k"Values Used In Travel Time/rtme of Concentration Calculations Shallow Concentrated Flow (After the initial 300 fL of sheet flow,R .0.1) it. 1. Forest with heavy ground litter and meadows(n=0,10) 3 2. Brushy ground with some trees(n-0.060) 5 3. Fallow or minimum tillage cultivation(n -0.040) 8 4. High grass In = 0.035) 9 S. Short grass,pasture and lawns(n•0.030) 11 e Nearly bare ground(n=0.025) 13 7. Paved and gravel areas(n.0.012) 27 Channel Flow(Intermittent)(At the beginning of visible channels:R•0.2) k, 1. Forested swale with heavy ground litter(n = 0.10) 5 2. Forested drainage course/ravine with defined channel bed(n=0.050) 10 3. Rock-lined waterway(n=0.035) t5 4. Grassed waterway(n.0-OW) 17 5. Earth-lined waterway(n=0.025) 20 6. CMP pipe(n=0.024) 21 7. Concrete pipe(0.012) 42 8. Other waterways and pipes 0.508/n Channel Flow(Continuous stream,R =0.4) k. 9. Meandering stream with some pools(n .0.040) 20 10. Rockained stream(n-0.035) 23 11. Grass-lined stream(n-0.030) 27 12. Other streams,man-made channels and pipe 0.807/n•• **See Chapter 5,Table 5.3.6C for additional Mannings'n'values for open channels 3.5.2-7 I/90 P�rmf ecmc-4 of aallc#-- S OW TECHNICAL INFORMATION REPORT (TIR) ADENDUM - SECTION V FOR THE PROPOSED SHORT PLAT OF: TERI PLACE CITY OF RENTON FILE #: LUA 99 -- 183, ShPI - H PREPARED FOR: HIGH POINT DEVELOPMENT, INC. ROBERT WEST 1903 POWERHOUSE RD. YAKIMA, WA 98902 (509) 453-2770 PREPARED BY: CASEY ENGINEERING. 15 SOUTH GRADY WAY SUITE 400 RENTON, WA 98055 (425) 204-8182 .0 W`tiSy�� DATE: MAY, 2000 7 S�ONAL� EXPIRES T-7-7-7/ �sw L�0040 0611 60 24 owro�y TERI PLACE TECHNICAL INFORMATION REPORT SECTION V CONVEYANCE SYSTEM ANALYSIS AND DESIGN The following information is contained within this sub-section: A. Discussion of Methods and Assumptions B. Creation of Existing Condition Upstream Basin"UPSTREAM". C. Conveyance Analysis for 25yr-24hr Storm D. Conveyance Analysis for 100yr-24hr Storm E. Structure and Reach Reports F. Copies of Information used from KCSWDM f � 1 t TERI PLACE— CONVEYANCE ANALYSIS SECTION V.A. Discussion of Methods and Assumptions The following Methods and Assumptions were used in this analysis: 1. The information obtained from the engineer for Swan Vue was not used due to the fact that I did not agree with the definition of the contributing basin. My basin is larger, and contains more residences—some of which have recently been constructed. 2. The basin breaks were determined in the field by observing high points on existing roads and observing topographical breaks within the lot areas. 3. It is assumed that all of the stormwater within the defined upstream basin enters the conveyance system at the southern most structure within Swan Vue. This is conservative since a portion of the basin flows overland directly onto the Teri Place site or directly to the east side of Park. However, all of the stormwater will eventually get to the existing 8"conveyance to the north of the Teri Place Site. 4. It is assumed that there are no existing stormwater detention facilities within the upstream basin. 5. The hydraulic program"WaterWorks"was used to perform the analysis of the existing and proposed conveyance system TERI PLACE— CONVEYANCE ANALYSIS SECTION V.B. Creation of Existing Condition Upstream Basin "UPSTREAM". Provided in this section is information that was used to create the upstream basin "UPSTREAM". Copies of information used from the KCS WDM is provided in Sub-section F. Exhibit A is provided in this Sub-section showing the limits of the upstream basin. i 61,�S/�eZi4/, �i i ZOO' a. Pery CC/v zf �Gsic/G�ccs 1,ierc VG iliec�,Jz/ GhG/ G.t/ G/�p� fjpr70i��Gs,GIe ,C- !�r/Gi'G /IdfGo� G A F 5- b, A 3y) ?,SZ = 3 • OOoc <-/Alt cry qyS �Y//7 - /aoyr 3. 91�2 T/� Co12f1/6 /�gsi - Co.> '7L/0/71iV,'I--OUf �a/ �/�S�`re4� �� iisi%J• 7, s�`o/'/yI 73 cis A CP %GCS - 1-7 5/22/00 10 :9 :29 am Casey Engineering page 1 TERI PLACE UPSTREAM DEVELOPED CONDITION 25yr-24hr PEAK RUNOFF BASIN SUMMARY BASIN ID: UPSTREAM NAME: UPSTREAM EXIST CONDITION SBUH METHODOLOGY TOTAL AREA. . . . . . . : 8 . 82 Acres BASEFLOWS : 0 .00 cfs RAINFALL TYPE. . . . : KC24HR PERV IMP PRECIPITATION. . . . : 3 .40 inches AREA. . : 5 .82 Acres 3 .00 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 68 . 00 98 .00 TC. . . . . 20 .00 min 15 .00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 2 . 73 cfs VOL: 1 .20 Ac-ft TIME: 480 min J 5/22/00 10 : 10 :15 am Casey Engineering page 1 TERI PLACE UPSTREAM DEVELOPED CONDITION 100yr-24hr PEAK RUNOFF --------------- BASIN SUMMARY BASIN ID: UPSTREAM NAME: UPSTREAM EXIST CONDITION SBUH METHODOLOGY TOTAL AREA. . . . . . . : 8 .82 Acres BASEFLOWS : 0 .00 cfs RAINFALL TYPE. . . . : KC24HR PERV IMP PRECIPITATION. . . . : 3 . 90 inches AREA. . : 5 . 82 Acres 3 .00 Acres TIME INTERVAL. . . . : 10 .00 min CN. . . . : 68 .00 98 .00 TC. . . . : 20 . 00 min 15 .00 min ABSTRACTION COEFF: 0 .20 PEAK RATE: 3 .43 cfs VOL: 1.47 Ac-ft TIME: 480 min 5/22/00 12 : 16 :27 am Casey Engineering page 1 TERI PLACE FRONTAGE CONVEYANCE ANALYSIS BASIN SUMMARY BASIN ID: DEVSITE NAME: DEV. COND. STORM SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1. 02 Acres BASEFLOWS: 0 .00 cfs RAINFALL TYPE. . . . : KC24HR PERV IMP PRECIPITATION. . . . : 3 .90 inches AREA. . : 0 .49 Acres 0 .53 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 68 .00 98.00 TC. . . . . 10 .00 min 5.00 min ABSTRACTION COEFF: 0.20 PEAK RATE: 0 . 62 cfs VOL: 0 .21 Ac-ft TIME: 470 min 1p Nks IF won Now"- wo =-N " h -A _■ 1 �' "1A ■ Sm 0 a M r • A IN NMI�x Elm Roo WL �� ate,� :1 � _, � •■i l �� NO IRI ILI . IWA �~ �� r-^= • -� -r--� ram=��- � `�� '� � ,1, ��- y(� ��,��■ � , _ � � i �, rill ` �� RS" U LOW 04, ISO- as it - � «� ►� ��L / �"�� r/� �� . . ►,,� : ;r1 t 1. WIN. w TERI PLACE— CONVEYANCE ANALYSIS SECTION V.C. Conveyance Analysis for 25yr-24hr Storm. Provided in this.sub-section is a copy of the Waterworks printout of the History file for the 100yr analysis of the proposed conveyance along the frontage of the Teri Place Project. Observations: 1. During the 25yr event,the existing and proposed conveyance has adequate capacity t�convey the design storm. As a result, no upsizing is required. When the property owners to the North of the Teri Place site decide to develop their property, the existing 8" conveyance will be replaced with a minimum 12"pipe —more than likely D.I. due to the shallow depth of the entire system. 2. At some point between the Teri Place site and the existing structure at the intersection of Park Ave N and N. 40`h Street,the 8" CMP changes to a 12"CMP. This analysis assumes that the entire reach consists of 8" CMP. 5/22/00 10 :39 :35 am Casey Engineering page 1 TERI PLACE FRONTAGE CONVEYANCE ANALYSIS 25yr-24hr PEAK RUNOFF HISTORY OF HYDROGRAPH ACTIVITY Date of Session: 5/22/00 10:37:55 am CHARHIS REMARK NEXT, THE HYDROGRAPHS IN REGISTERS 1 THROUGH 20 ARE CLEARED, AND THE PRECIPITATION FOR THE CONTRIBUTING BASIS ARE CHANGED TO THE 25YR-24HR STORM OF 3.4 INCHES. LSTEND ZERO 1 20 CHANGE PRECIP 3.40 DEVSITE UPSTREAM LSTEND REMARK THE HYDROGRAPH REPRESENTING THE UPSTREAM OFF-SITE CONTRIBUTING BASIN IS CREATED AND STORED IN HYDROGRAPH REGISTER °HYD1" LSTEND MOVE UPSTREAM to 1 2.7316 cfs 1.2010 ac-ft 8.00 hrs REMARK "HYD11 IS NOW ROUTED THROUGH THE EXISTING 121 UPSTREAM CONVEYANCE, INTO THE PROPOSED ON-SITE 12, CONVEYANCE SYSTEM AND THROUGHT THE EXISTING 8" DOWNSTREAM CONVEYANCE SYSTEM. LSTEND ROUTE HYDROGRAPH 1 THROUGH REACH FRONTAGE Network FRONTAGE Reach <AREA> <Act Q> <Q Full> I Full Ndepth <Diam> <NVel> <FVel> Carea ------------------------------- - - RS2 8.82 2.73 4.25 64.23 7.33 12.00 5.43 5.56 RS1 8.82 2.73 8.56 31.90 4.85 12.00 9.15 11.19 R3 8.82 2.73 9.40 29.05 4.61 12.00 9.84 12.29 R2 9.84 3.22 3.72 86.59 6.11 8.00 11.26 10.95 DEVSITE RN 9.84 3.22 38.81 8.31 3.64 18.00 12.63 22.54 REMARK SINCE SOME OF THE FLOW WITHIN THE CONVEYANCE IS EITHER NEARING OR IS WITHIN PRESSURE FLOW, A BACKWATER ANALYSIS IS PERFORMED TO ENSURE THAT ALL OF THE STORMWATER IS CONTAINED WITHIN THE PROPOSED AND EXISTING CONVEYANCE SYSTEM. 5/22/00 10 :39 :35 am Casey Engineering page 2 TERI PLACE FRONTAGE CONVEYANCE ANALYSIS 25yr-24hr PEAK RUNOFF HISTORY OF HYDROGRAPH ACTIVITY LSTBND HGLINE HGL1 Hydraulic Gradeline for Reach HGLI <-FROM-> <--TO--> <FLOW> floss Ent HGL Entboss ExtLoss OutLet Inlet AppHead BndHead JunHead HeadWtr -cb/mh- 96.49 CB#N 3.22 2.00 tw & do <dc: Inlet Ctrl Assumed 98.52 1.32 1.76 0.00 98.90 101.04 CB#2 CB#N 3.22 14.91 tw & do <dc: Inlet Ctrl Assumed 118.35 0.00 0.00 0.00 116.76 117.00 CB#3 CB#2 2.73 0.46 tw & do <dc: Inlet Ctrl Assumed 120.42 0.19 0.00 0.00 120.01 121.50 CB#S1 CB#3 2.73 1.70 tw & do <dc: Inlet Ctrl Assumed 122.13 0.19 0.00 0.00 121.72 123.50 CB#S2 CB#S1 2.73 1.80 tw & do <dc: Inlet Ctrl Assumed 123.94 0.00 0.00 0.00 123.72 124.30 REMARK IT HAS BEEN SHOWN THAT THE PROPOSED CONVEYANCE ALONG THE FRONTAGE OF THE 'TERI PLACE, SITE IS DESIGNED TO CONVEY THE 25YR DESIGN STORM AS REQUIRED BY THE KCSWDM. LSTEND End program file C:\CASEYE-1�99013-"1\WATERW'l�FRON025.pgm TERI PLACE— CONVEYANCE ANALYSIS SECTION V.D. Conveyance Analysis for 100yr-24hr Storm Provided in this sub-section is a copy of the WaterWorks printout of the History file for the 100yr analysis of the proposed conveyance along the frontage of the Teri Place Project. The program is identical to the 25yr analysis except for the precipitation—which was changed to the 100yr value of 3.9". Observations: 1. During the 100yr event,the existing 8" CMP conveyance to the north of the site will be operating under pressure flow conditions. However all of the stormwater will remain within the system. 2. It appears that the existing Storm Structure to the south within Swan Vue has overtoped based upon the assumptions used in the analysis. If this in fact does occur,then any stormwater will reenter the system once it gets to Teri Place. 3. Once the stormwater has arrived at the existing system at the intersection of Park and N. 40''the is adequate capacity(38cfs) for the area of study and the remaining contributing basin to the east. 5/22/00 10 :45 :0 am Casey Engineering page 1 TERI PLACE FRONTAGE CONVEYANCE ANALYSIS 100yr-24hr PEAK RUNOFF HISTORY OF HYDROGRAPH ACTIVITY Date of Session: 5/22/00 10:42:19 am CLEARHIS REMARK NEXT, THE HYDROGRAPHS IN REGISTERS 1 THROUGH 20 ARE CLEARED, AND THE PRECIPITATION FOR THE CONTRIBUTING BASIS ARE CHANGED TO THE 100YR-24HR STORM OF 3.9 INCHES. LSTEND ZERO 1 20 CHANGE PRECIP 3.90 DEVSITE UPSTREAM LSTEND REMARK THE HYDROGRAPH REPRESENTING THE UPSTREAM OFF-SITE CONTRIBUTING BASIN IS CREATED AND STORED IN HYDROGRAPH REGISTER "HYD1" LSTEND MOVE UPSTREAM to 1 3.4265 cfs 1.4703 ac-ft 8.00 hrs REMARK 1HYD11 IS NOW ROUTED THROUGH THE EXISTING 121 UPSTREAM CONVEYANCE, INTO THE PROPOSED ON-SITE 121 CONVEYANCE SYSTEM AND THROUGHT THE EXISTING 8" DOWNSTREAM CONVEYANCE SYSTEM. LSTEND ROUTE HYDROGRAPH 1 THROUGH REACH FRONTAGR Network FRONTAGE Reach <AREA> <Act Q> <Q Full> I Full Ndepth <Diaz> <NVel> <FVel> Carea RS2 8.82 3.43 4.25 80.57 8.63 12.00 5.67 5.56 RS1 8.82 3.43 8.56 40.02 5.50 12.00 9.76 11.19 R3 8.82 3.43 9.40 36.44 5.22 12.00 10.45 12.29 R2 9.84 4.02 --------Pressure Flow-------- 11.52 DEVSITE RN 9.84 4.02 38.81 10.36 4.06 18.00 13.48 22.54 REMARK SINCE SOME OF THE FLOW WITHIN THE CONVEYANCE IS EITHER NEARING OR IS WITHIN PRESSURE FLOW, A BACKWATER ANALYSIS IS PERFORMED TO ENSURE THAT ALL OF THE STORMWATER IS CONTAINED WITHIN THE PROPOSED AND EXISTING CONVEYANCE SYSTEM. 5/22/00 10 :45 :0 am Casey Engineering page 2 TERI PLACE FRONTAGE CONVEYANCE ANALYSIS 100yr-24hr PEAK RUNOFF HISTORY OF HYDROGRAPH ACTIVITY LSTEND HGLINE HGL1 Hydraulic Gradeline for Reach HGLI <-FROM-> <--TO--> <FLOW> floss Ent HGL BntLoss ExtLoss OutLet Inlet AppHead BndHead JunHead HeadWtr -cb/mh- 96.53 CB#N 4.02 2.00 tw & do <dc: Inlet Ctrl Assumed 98.59 2.06 2.74 0.00 99.18 101.04 CB#2 CB#N 4.02 20.13 114.47 0.41 2.06 116.94 0.00 0.00 0.00 0.00 114.47 117.00 CB#3 CB#2 3.43 0.75 tw & do <dc: Inlet Ctrl Assumed 121.42 0.30 0.00 0.00 120.78 121.50 CB#S1 CB#3 3.43 0.28 tx & do <dc: Inlet Ctrl Assumed 123.13 0.30 0.00 0.00 122.48 123.50 CB#S2 CB#S1 3.43 1.22 tw & do <dc: Inlet Ctrl Assumed 124.95 0.00 0.00 0.00 124.40* 124.30 REMARK IT HAS BEEN SHOWN THAT THE PROPOSED CONVEYANCE ALONG THE FRONTAGE OF THE 'TERI PLACE" SITE IS DESIGNED TO CONVEY THE 100YR DESIGN STORM AS REQUIRED BY THE KCSWDM. LSTBND End program file C:�CASEYE'l�99013-"1\WATERW"1\FRON100.pgm TERI PLACE— CONVEYANCE ANALYSIS SECTION V.E. Structure and Reach Reports The following information is contained in this sub-section: 1. WaterWorks Printout of Storm Structures used in the Analysis. 2. WaterWorks Printout of Pipe Reaches used in the Analysis. 5/22/00 11 :27 :42 am Casey Engineering page 1 TERI PLACE FRONTAGE CONVEYANCE ANALYSIS ------------------- STRUCTURE REPORT PROPOSED STRUCTURE REACH ID No. CB#2 Location : NW END OF PROJECT North 9762 .5000 Str Type : CB#2 East 10009 .0000 Str Cat : Catch Basin Rim Elev 117 .0000 Area/sump: 0 . 00 sf/1 .50 ft Bottom El : 112 .3000 Cont Area: DEVSITE Hgrade El : 114 .4660 ft Bend. . . . . : No special shape Ent type. : Area/sump: Ent Loss : 0 .412 Exit: 2 .060 App Vel: 0 . 000 Junct: 0 .000 Bend: 0 .000 Reach <Invert> <Diam> < n > <End> R2 113 . 800 8 .00 0 . 012 Upper R3 115 . 120 12 .00 0 . 012 Lower PROPOSED STRUCTURE REACH ID No. CB#3 Location : SW END OF PROJECT North 9670 .8000 Str Type : CB#3 East 10007 .3000 Str Cat : Catch Basin Rim Elev : 121.5000 Area/sump: 0 . 00 sf/1.50 ft Bottom El: 118 .3000 Cont Area: Hgrade El : 120 .7784 ft Bend. . . . . : No special shape Ent type. : Area/sump: Ent Loss : 0 . 059 Exit: 0 .296 App Vel : 0 .296 Junct: 0 .000 Bend: 0 . 004 Reach <Invert> <Diam> < n > <End> R3 119 .800 12 . 00 0 .012 Upper RS1 119 .800 12 . 00 0 .012 Lower EXISTING STRUCTURE REACH ID No. CB#N Location : INTERSECTION N40TH & PARK North 9976 . 8000 Str Type : EXISTING CB East 10017 .8000 Str Cat : Stm Manhole Rim Elev 101 .0400 Str Diam : 0 . 00 in Bottom El : 98 . 1900 Cont Area: Hgrade El : 99 . 1803 ft Bend. . . . . : No special shape Ent type. : Str Diam : Ent Loss : 0 .016 Exit : 0 .080 App Vel : 2 .060 Junct : 0 .000 Bend: 2 .742 Reach <Invert> <Diam> < n > <End> RN 98 .190 18 .00 0 .012 Upper R2 98 . 890 8 .00 0 . 012 Lower 5/22/00 11 :27 :42 am Casey Engineering page 2 TERI PLACE FRONTAGE CONVEYANCE ANALYSIS STRUCTURE REPORT EXISTING STRUCTURE REACH ID No. CB#S1 Location : EXIST STRUCT S . OF SITE North 9630 .7000 Str Type : CB#S1 East 10004 .6000 Str Cat : Catch Basin Rim Elev 123 .5000 Area/sump: 0 .00 sf/1 .50 ft Bottom El : 120 .0000 Cont Area: Hgrade El : 122 .4838 ft Bend. . . . . : No special shape Ent type. : Area/sump: Ent Loss: 0 . 059 Exit : 0 .296 App Vel : 0 . 296 Junct : 0 .000 Bend: 0 .005 Reach <Invert> <Diam> < n > <End> RS1 121. 500 12 .00 0 .012 Upper RS2 121 . 500 12 .00 0 . 012 Lower EXISTING STRUCTURE REACH ID No. CB#S2 Location : EXIST STRUCT S . OF SITE North 9458.2000 Str Type : CB#S2 East 10004 .4000 Str Cat : Catch Basin Rim Elev 124 .3000 Area/sump: 0 . 00 sf/1 .50 ft Bottom El : 121. 8000 Cont Area: Hgrade El : 124 .4000 ft Bend. . . . . : No special shape Ent type. : Area/sump: Ent Loss : 0 .059 Exit : 0 .296 App, Vel : 0 .000 Junct: 0 . 000 Bend: 0 .000 Reach <Invert> <Diam> < n > <End> RS2 123 .300 12 . 00 0 .012 Upper 5/22/00 11 :26 :33 am Casey Engineering page 1 TERI PLACE FRONTAGE CONVEYANCE ANALYSIS REACH SUMMARY PIPE REACH ID NO. R2 From: CB#2 To: CB#N Pipe Diameter: 0 . 6667 ft n: 0 .0120 Pipe Length : 214 .4806 ft s : 0 . 0695 Up invert : 113 .8000 ft down invert: 98 . 8900 ft Collection Area: 9 .8400 Ac. Design Flow 4 . 0210 cfs Dsgn Depth: ft Pipe Capacity 3 .7229 cfs Design Vel 11 .5193 fps Travel Time: 0 .31 min Pipe Full Vel 10 .9456 fps (surcharged tt) PIPE REACH ID No. R3 From: CB#3 To: CB#2 Pipe Diameter: 1 .0000 ft n: 0 . 0120 Pipe Length 91. 7158 ft s : 0 .0510 Up invert : 119 . 8000 ft down invert: 115 .1200 ft Collection Area: 8 . 8200 Ac. Design Flow 3 .4265 cfs Dsgn Depth: 0 .43 ft Pipe Capacity 9 .4041 cfs Design Vel 10 .4545 fps Travel Time: 0 .15 min Pipe Full Vel 12 .2883 fps PIPE REACH ID No. RN From: CB#N To: Pipe Diameter: 1 .5000 ft n: 0 . 0120 Pipe Length 20 . 0000 ft s : 0 . 1000 Up invert 98 . 1900 ft down invert : 96 .1900 ft Collection Area: 9 . 8400 Ac. Design Flow 4 . 0210 cfs Dsgn Depth: 0 .34 ft Pipe Capacity 38 . 8143 cfs Design Vel 13 .4757 fps Travel Time: 0 .02 min Pipe Full Vel 22 .5416 fps PIPE REACH ID No. RS1 From: CB#S1 To: CB#3 Pipe Diameter: 1 . 0000 ft n: 0 .0120 Pipe Length 40 . 1908 ft s: 0 .0423 Up invert : 121 .5000 ft down invert : 119 . 8000 ft Collection Area: 8 .8200 Ac. Design Flow 3 .4265 cfs Dsgn Depth: 0 .46 ft Pipe Capacity 8 .5620 cfs Design Vel 9 .7554 fps Travel Time: 0 .07 min Pipe Full Vel 11 .1880 fps 5/22/00 11:26 :33 am Casey Engineering page 2 TERI PLACE FRONTAGE CONVEYANCE ANALYSIS REACH SUMMARY PIPE REACH ID No. RS2 From: CB#S2 To: CB#S1 Pipe Diameter: 1 . 0000 ft n: 0 . 0120 Pipe Length : 172 .5001 ft s : 0 .0104 Up invert : 123 .3000 ft down invert: 121.5000 ft Collection Area: 8 . 8200 Ac. Design Flow 3 .4265 cfs Dsgn Depth: 0 .72 ft Pipe Capacity 4 .2526 cfs Design Vel 5 .6670 fps Travel Time: 0 .51 min Pipe Full Vel 5 .5569 fps TERI PLACE— CONVEYANCE ANALYSIS SECTION V.F. Copies of Information used from KCSWDM The following information is contained in this sub-section: 1. Figure 3.5.2.A—Hydrologic Soil Group Of The Soils In King County 2. Table 3.5.213—CSC Western Washington Runoff Curve Numbers 3. Figure 3.5.1F—25Year 24-Hour Isopluvials 4. Figure 3.5.1 H— 1 OOYear 24-Hour lsopluvials 5. Table 4.3.4V—Manning's "n"Values For Pipes KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL (2) CN values can be area weighted when they apply to pervious areas of similar CN's (within 20 CN points). However, high CN areas should not be combined with low CN areas (unless the low CN areas are less than 15% of the subbasin). In this case, separate hydrographs should be generated and summed to form one hydrograph. FIGURE 3.5.2A HYDROLOGIC SOIL GROUP OF THE SOILS INKING COUNTY HYDROLOGIC HYDROLOGIC SOIL GROUP GROUP' SOIL GROUP GROUP* Alderwood C Orcas Peat D Arents, Alderwood Material C Oridia D Arents, Everett Material B Ovall C Beausite C Pilchuck C Bellingham D Puget D Briscot D Puyallup B Buckley D Ragnar B Coastal Beaches Variable Renton D Earimont Silt Loam D Riverwash Variable Edgewick C Salal C Everett A/B °Sammamish D Indianola A Seattle D Kitsap C Shacar D Klaus C Si Silt C Mixed Alluvial Land Variable Snohomish D Neilton A Sultan C Newberg B Tukwila D Nooksack C Urban Variable Normal Sandy Loam D Woodinville I D HYDROLOGIC SOIL GROUP CLASSIFICATIONS A. (Low runoff potential). Soils having high infiltration rates, even when thoroughly wetted, and consisting chiefly of deep, well-to-excessively drained sands or gravels. These soils have a high rate of water transmission. B. (Moderately low runoff potential). Soils having moderate infiltration rates when thoroughly wetted, and consisting chiefly of moderately fine to moderately coarse textures. These soils have a moderate rate of water transmission. C. (Moderately high runoff potential). Soils having slow infiltration rates when thoroughly wetted, and consisting chiefly of soils with a layer that impedes downward movement of water, or soils with moderately fine to fine textures. These soils have a slow rate of water transmission. D. (High runoff potential). Soils having very slow infiltration rates when thoroughly wetted and consisting chiefly of clay soils with a high swelling potential, soils with a permanent high water table, soils with a hardpan or clay layer at or near the surface, and shallow soils over nearly impervious material. These soils have a very slow rate of water transmission. * From SCS, TR-55, Second Edition, June 19M, Exhibit A-1. Revisions made from SCS, Soil Interpretation Record, Form #5, September 1988. 3.5.2-2 11/92 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TABLE 3.5?13 SCS WESTERN WASHINGTON RUNOFF CURVE NUMBERS SCS WESTERN WASHINGTON RUNOFF CURVE NUMBERS (Published by SCS in 1982) Runoff curve numbers for selected agricultural, suburban and urban land use for Type 1A rainfall distribution, 24-hour storm duration. CURVE NUMBERS BY HYDROLOGIC SOIL GROUP LAND USE DESCRIPTION A B C D Cultivated land(1): winter condition 86 91 94 95 Mountain open areas: low growing brush and grasslands —T—74 82 89 92 Meadow or pasture: 65 78 85 89 Wood or forest land: undisturbed or older second growth 42 64 76 81 Wood or forest land: young second growth or brush 55 72 81 86 Orchard: with cover crop 81 88 92 94 Open spaces, lawns, parks, golf courses, cemeteries, landscaping. good condition: grass cover on 75% or more of the area 68 80 86 90 fair condition: grass cover on 50% to 75% of the area 77 B5 90 92 Gravel roads and parking lots 76 85 89 91 Dirt roads and parking lots 72 82 87 89 Impervious surfaces, pavement, roofs, etc. _ 98 98 98 98 N1 �r Open water bodies: lakes, wetlands, ponds, etc. 100 100 100 100 Single Family Residential (2) Dwelling Unit/Gross Acre % Impervious (3) 1.0 DU/GA 15 Separate curve number 1.5 DU/GA 20 shall be selected 2.0 DU/GA 25 for pervious and 2.5 DU/GA 30 impervious portion 3.0 DU GA 34 of the site or basin 3.5 DU/GA 38 4.0 DU/GA 42 4.5 DU/GA 46 5.0 DU/GA 48 5.5 DU/GA 50 6.0 DU/GA 52 6.5 DU/GA 54 7.0 DU/GA 56 Planned unit developments, % impervious condominiums, apartments, must be computed commercial business and industrial areas. (1) For a more detailed description of agricultural land use curve numbers refer to National Engineering Handbook, Section 4, Hydrology, Chapter 9, August 1972. (2) Assumes roof and driveway runoff is directed into street/storm system. (3) The remaining pervious areas (lawn) are considered to be in good condition for these curve numbers. 3.5.2-3 11/92 -, _ s/� Ml� IN DIP19-po 11 • • ' •��w A �t s - ��' ►� ILIVA Mi ?_ sly - .� AbI.I KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TABLE 4.3.4V MANNING'S "n" VALUES FOR PIPES Analysis Method Type of Pipe Material Uniform Backwater Flow Flow (Preliminary (Capacity design) Verification) A. Concrete pipe and CPEP-smooth interior pipe 0.014 0.012 B. Annular Corrugated Metal Pipe or Pipe Arch: 1 . 2-2/3" x 1/2" corrugation (riveted) a. plain or fully coated 0.028 0.024 b. paved invert (40% of circumference paved): (1) flow full depth 0.021 0.018 (2) flow 0.8 depth 0.018 0.016 (3) flow 0.6 depth 0.015 0.013 c. treatment 5 0.015 0.013 2. 3" x 1 " corrugation 0.031 0.027 3. 6" x 2" corrugation (field bolted) 0.035 0.030 C. Helical 2-2/3" x 1/2" corrugation and CPEP-single wall 0.028 0.024 D. Spiral rib metal pipe and PVC pipe 0.013 0.011 E. Ductile iron pipe cement lined 0.014 0.012 F. High density polyethylene pipe (butt fused only) 0.009 0.009 (2) Backwater Analysis Method Used to analyze the capacity of both proposed, and existing, pipe systems to convey the peak rate of runoff for the 25, and 100-year design storm events. (Note, structures for proposed pipe systems must be demonstrated to provide a minimum of 0.5 feet of freeboard between the headwater surface (hydraulic grade line) and the top of the structure for the 25 year peak rate of runoff. Structures may overtop for the 100-year peak rate of runoff as allowed by Core Requirement #4 in Section 1 .2.4. When overtopping occurs for the 100-year peak rate of runoff the additional flow over the ground surface is analyzed using the methods described in Section 4.3.7 and added to the flow capacity of the pipe system determined, as described below.) This method is used to compute a simple backwater profile (hydraulic grade line) through a proposed, or existing, pipe system for the purposes of verifying adequate capacity. It incorporates a re-arranged form of Manning's Equation expressed in terms of friction slope lie, slope of the energy grade line in ft/ft). The friction slope is used to determine the head loss in each pipe segment due to barrel friction, which can then be combined with other head losses to obtain water surface elevations at all structures along the pipe system. The backwater analysis begins at the downstream end of the pipe system and is computed back through each pipe segment and structure upstream. The friction, entrance and exit head losses computed for each pipe segment are added to that segment's tailwater elevation (the water surface elevation at the pipe's outlet) to obtain its "outlet control" headwater elevation. This elevation is then compared with the "inlet control" headwater elevation, computed assuming the pipe's inlet alone is controlling capacity using the methods for inlet control presented in Section 4.3.5. The condition that creates the highest headwater elevation then determines the pipe's capacity. The approach velocity head is then subtracted from the controlling headwater elevation and the junction and bend head losses are then added to compute the total headwater elevation which is then used as the tailwater elevation for the upstream pipe segment. 4.3.4-16 11/92 SS MH MH 'A' TYPE II RIM=98.90 EX STORM DRAIN MH SOLID LOCKING LID IE 8" (S) 88.95 RIM=101 .27 IE 18" CONC. IN (S) 96.92 IE 18" CONC. IN (E) 96.42 IE 18" CONC. IN (W) 96.34 W. SURF 96.42 ONORTH 40TH STREET I � EXISTING STORM LINE 18" CPEP ® 6.97% EX STORM DRAIN CB N I RIM= 101 .04 I IE 12" CONC. IN (NE) 98.89 IE 12" CONC. IN (S) 98.89 I IE 18" CPEP OUT (N) 98.19 I I Io I 0 � I 1-4 o � r t-Tj I o I o s I I EXISTING STORM 8 CONC. PIPE @ 6.97% I EX WATER METERS o R I EXISTING 8 STORM 236' @ 6.97% I CB2 TYPE IL CB 2 2 0 STA 1+16.75 5'LT I (@ TE FL EXTENDED TO FF CURB) RIM EL = 117.0+/- EXIST EDGE OF PVM'T-E. SIDE IE OUT 8" CMP (N) = 113.8 IE IN 12" D.I. (E) = 115.12 EXIST FOG LINE.-E. SIDE - IE IN 12" D.I. {S} = 115.12 10 EXISTING P.P. 120 HI POINT STA 2+58.94 TO BE RELOCATED 2 1 HI POINT ELEV=122.21 EXISTING 8" STORM CMP PIPE IE=115.33 N ABANDON ---- EXISTING DITCH ABANDON EXISTING 12" WATER LINE APPROX. \ LOCATION PER DWG W-230507 --� 9 12" D.I.® 5.1% \_ EX WATER METER I - �- EXISTING 8" STORM CMP PIPE IE=117.22 ABANDON CB TYPE EXISTING 8" STORM RIM EL = 121.5+/- CMP PIPE IE=118.44 / IE IN 12 D.I. (S) = 1 .8 ABANDON IE OUT 1 D.1 (N) = 19.8 7 EXISTING DITCH C J7 ABANDON EX 8" S.S. EXIST EDGE OF PVM'T-W. SIDE - - ---- REPL w. 12" 1 1 MAIN IN EXIST Q EXIST FOG LINE-W. SIDE EXISTING P.P. EXISTING 8" STORM I TO/BE RELOCA D CMP PIPE IE=119.8 1 10' CbORD WITH S.E. Z o D X I C B#Sl 0 -u �Q . ... �,�,. sr�•., o EXIST STORM INLET 0 m m lF••9G - P co _ N �:, RIM EL- D) \ \ NLna •� co �•� 12" CMP S IE=121.5 (ASSUMED)�;� 8" CMP N -REPLACE w. 12" D.I. om D �' - es's, ��`•� �_ 12" D.I. �N� IE=121.5 (ASSUMED) 0 of •�� , 2 D m o EX S.S. M.H. RIM=125.28 I.E.=105.35 Zoe N - - - - - -- - - __._ - - I of 301 N I oc � 0 I 0 th o I I I I EX S.S. M.H. D I I I I I I ''d o b I n, N lip O - - - N� CB#S2 EX STORM DRAIN ~ N I I I IE 12" CMP OUT (S) -42" MD I EXIST STORM INLET (APROX LOC) � b 2 2M CPEP 4.3 (ASSUMED) (S) = 123.3 12" CPEP (N) = 123.3 y P y SWAM VUE \ om � \Ao 2 1 � I