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SWP272071(1)
Boeing Commercial Airplane Group P.O.Box 3707 Seattle,WA 98124-2207 September 3, 1996 6-8A00-LLP-2247 Ron Straka BOE/NG Supervisor Surface Water Utility, City of Renton 200 Mill Avenue South Renton, WA 98055 Dear Mr. Straka: I am writing in reference to our recent conversation(August 20, 1996) in which we discussed the close out of the storm water variance data collection requirements for the Boeing Customer Services Training Center(CSTC) at the Longacre site. It was concluded, based on the data collected and submitted to the City, that the intent of the variance granted on May 20, 1992 has been met and the system installed at the CSTC is functioning as designed. As way of background, the City issued a storm water variance to the Boeing Company's CSTC site to allow an alternate storm water system to be installed. The system was designed with the direction of Dr. Richard R. Horner of the University of Washington's Environmental Engineering and Science Department. The variance required that certain samples be taken at the site and submitted to the City for review. Due to site constraints, it proved difficult to adhere to the strict monitoring regiment. With your concurrence, a modified sampling regime was approved (memo 6-8W5H- LA-5284, dated November 14, 1995), and sample data was submitted in May of 1996. Based on the sample data, the Boeing Company feels that the intent of the variance has been met and that the system is functioning as designed. At this time we request that the City review the data submitted and provide acknowledgment that the variance requirements have been met and that no further monitoring is required. If you have any questions or comments, please do not hesitate to call me on 544-1644. Larry E. Allen CITY OF RENTON MEMORANDUM DATE: May 20, 1992 TO: Gregg Zimmerman Tom Kriss Lenora Blauman FROM: Ron Straka A " SUBJECT: The Boeing Company's Customer Service Training Center Project Code Modification/Alteration Request The Surface Water Utility has reviewed the Boeing Company's code modification/alteration request for the Customer Service Training Center (CSTC)project as allowed under Ordinance No.4342. The Boeing Company has requested code modification/alteration to the City of Renton Storm and Surface Water Drainage chapter 4-22. The code modification/alteration request (see attached documents) pertains to the portions of the City adopted 1990 King County Surface Water Design Manual (KCSWDM) Core requirement No 3 (biofiltration requirement) and Special Requirement No. 6 (coalescing plate oil/water separators)surface water management standards. The Surface Water Utility approves of the requested code modification/alteration request based upon the information provided by the Boeing Company (see attachments). This information includes a technical letter from Dr. Richard R. Horner who teaches at the University of Washington's Environmental Engineering and Science Department. Dr. Horner a nationally respected expert in the field of water quality and resource engineering. Dr Horner reviewed the code requirements for the Boeing CSTC project and estimated the pollutant removal that would be obtained. He then reviewed the proposed storm and surface water management facilities design for the Boeing CSTC and estimated the percentage of pollutant removal that would be achieved by the Boeing system. This comparison shows that the proposed Boeing CSTC storm and surface water management plan will remove more pollutants than the code requirements would for the selected parameters. The Surface Water Utility approves the code modification/alteration request based upon this evidence and accepts the conceptual drainage plan for the Boeing CSTC project. The request demonstrates that the proposed design meets the intent of the code, will accomplish equivalent pollutant removal as required by code(actually exceeds code requirements), it will equally protect the environment and satisfies the other requirements of Ordinance No 4342 as discussed in the formal request. As allowed by Ordinance No 4342, the following conditions of this approved code modification/alteration request must be complied with by the Boeing Company as specified in the conditions. The conditions of the code modification/alteration request are as follows: 1.) The applicant (The Boeing Company) shall develop a Water Quality Monitoring and Assessment Plan to be approved by the City of Renton Surface Water Utility. The Utility recommends that the Boeing Company receive direction from Dr.Horner in the development of the Water Quality Monitoring and Assessment Plan. This condition must be complied with prior to the issuance of the CSTC projects construction/building permit. 2.) The applicant shall implement the approved monitoring plan with continuous monitoring for a period of time as specified in the approved plan based upon Dr. Horner's recommendations. The water quality monitoring shall start following the completion of construction at the time of the projects Final Occupancy Permit issuance(CSTC building). 3.) Upon completion of the approved water quality monitoring period, the applicant shall provide within two months the City of Renton with technical report which documents the results of the water quality monitoring and assess the effectiveness of the proposed systems pollutant removal rate for comparison with code pollutant removal rates. If the proposed CSTC storm and surface water systems pollutant removal rates are less than what the code requirement pollutant removal rates are, then the Boeing Company shall install the required coalescing plate oil/water separators, or propose alternate measures which may be subject to additional conditions by the City of Renton Surface Water Utility. 4.) The applicant (Boeing)shall provide the City of Renton with a bond that is valid for the duration of the approved water quality monitoring duration period plus six months,which is equal to 100% of the cost to design/construct/install the projects required coalescing plate oil/water separators. These conditions are justified in order that the proposed CSTC storm and surface water management system works as certified by the applicants engineer and to ensure protection of the public's safety and health as well as the environment. If you have any questions regarding this subject,please contact me at(206)277-5547. Boeing Commercial Airplane Group P.O.Box 3707 Seattle,WA 98124-2207 May 16, 1995 R-1150-95-DST-247 Ron Straka, P.E. Engineering Supervisor BOE/NG Surface Water Utility Planning/Building/Public Works Department City of Renton 200 Mill Avenue South Renton, WA 98055 Dear Mr. Straka: Subject: Boeing Customer Services Training Center (Longacres) Stormwater Monitoring Plan Reference: (a) meeting between R. Straka, City of Renton, A. Clapham, Boeing, B. Heath, Boeing and D. Turner, Boeing on April 24, 1995. As agreed upon during your telephone coversation and the above referenced meeting with Andrew Clapham of Boeing's Facilities Department and Doris Turner of my staff, Renton Environmental Affairs has prepared a summary of the activities, concerns and modifications involving the stormwater sampling system at the Customer Services Training Center(CSTC). As requested in the conditons of the mitigated Determination of Non-Significance for the CSTC, a stormwater quality monitoring and assessment program was approved prior to issuance of the sites building permit. This plan was developed by Dr. Richard H. Horner of the University of Washington's Environmental Engineering and Science Department and approved by the City of Renton. Enclosed is a copy of this monitoring and assessment plan. Also as part of the mitigation conditons, implementation of this plan was requested at the time of occupancy. On July 20, 1994 installation of the monitoring system was completed. As part of the start-up effort, several problems and necessary modifications to the existing system were identified. These included both operational modifications and sampling modifications and are summarized in the attached memo dated September Page 2 Mr. R. Straka R-1150-95-DST-247 29, 1994 to Andrew Clapham of Boeing. Subsequent to this memo several additional operational problems have occurred and are summarized below. • Due to dry weather and infiltration, no water reached the main vault until mid-October, therefore, no sampling was possible prior to that time. • Due to interferences from the sprinkler system, the rain gauges had to be BOE/NG elevated to approximately 8 feet to avoid false triggering of the sampling system. . The stop-log weir at the main vault leaks and, therefore, accurate flow measurement are not possible. • During periods of high flow through the system, the check valve located on the discharge pipe into Springbrook Creek does not discharge water fast enough to prevent total submersion of the stop-log weir resulting in inaccurate flow measurement. To address this problem and the one above, the sampling location will be moved to the outlet of the main pond as shown on the enclosed map and agreed to at the above referenced meeting. • During the cold weather in December, the rain gauges froze and did not trip the samplers. During dry sunny weather when the gauge thawed the samplers were falsely tripped. Heat tracing will be installed on these gauges to avoid false initiation of the samplers. • Also during the cold weather, the ISCO sampler appeared to be having some computer problems and some of the programmed parameters changed back to the default parameters. These samplers are in locked sheds, therefore, tampering was not believed to be the cause of the problem. These units have been reprogrammed and appear to be operating correctly. • Several problems were encountered with the ISCO data software (FLOWLINK) program and at times no access to the data collected was possible, or peculiar results were obtained. ISCO was contacted and the specific problem files were submitted for evaluation. As a result; ISCO discovered a problem in their software which they corrected and distributed a new version to all their users. • The distributor arm on the sampler at the main vault jammed and required replacement with a new sampler. Page 3 Mr. R. Straka R-1150-95-DST-247 • During a storm event in January, the weirs in both sites 1 and 2 were blown out of the pipe. Hence, flow conditions could not be measured. Both of these weirs have been re-installed and re-calibrated. Due to the above mentioned implementation problems, data for the first full water year(October 1994- September 1995) will not be available. The monitoring BOE/NG program will therefore commence October 1995 for two full water years. Boeing understands successful monitoring is required to be implemented for a minimum of two (2) complete water years and thus will continue monitoring through September 1997. At the end of this time, the program will be re-evaluated. We appreciate your understanding and support with the implementation problems we have encountered to date and assure you we will fulfill those requirements as part of the mitigation conditons. We will keep you apprised of the progress we make with the installation of an alternate flow measuring device at the main vault and the sampling protocols being used. If you have any questions or require any additional information please contact Doris Turner at 965-2703. Sincerely, L. M. Babich III Environmental Affairs Manager Org. R-1150/MS 63-41 Enclosures e e e e e am er 1 , wit ► i . � n �y 1, 25-01 25-02 r,. Sampler Site #3* y Gtee at°°� N GjQ "New Location for Sampler 4/95 CSTC SITE DEVELOPMENT SITE PLAN STORM WATER TREATMENT AND AQUATIC FEATURES September 29, 1994 R-1150-94-DST-602 To: Andrew Clapham 6H-LT cc: Phil Vanderbrake 17-MA Steve Karich 63-41 Larry Tibbels 17-MA Mike Black 17-WK Mike Babich 63-41 Lori Pitzer 6H-LT Subject: Longacres Stormwater Sampling Program As part of the code modification for the Customer Service Training Center (CSTC) a Water Quality Monitoring and Assessment Plan was developed for the site under the direction of Dr. Richard Horner of the University of Washington's Environmental Engineering and Science Department. As described below, this plan is being implemented at the CSTC. • Sampling Points: Three sampling points have been identified for the site. One each are located at the inflow of the two secondary ponds and one is located in the vault which discharges into Springbrook Creek. • Sampling Schedule: Sampling will begin immediately upon treatment system start-up and will continue for two full water years. It is expected that a 1-2 month time period will be required to debug and fine tune the sampling system. To date no effluent has reached the Springbrook Creek through the final vault, however, flow into the pond from the other two sampling sites has occurred. As a result, no samples have been analzyed to date, however, flow data is being collected. The monitoring will follow the conditions listed on pages 7 - 9 of Dr. Homer's report (Stormwater Quality Monitoring and Assessment Program, Boeing Customer Service Training Center, October 1992). Flow will be measured continuously at each sampling point. If possible, analysis of at least 16 sample sets each year, approximately 75% (12) during the wet season (October 1-April 30) and 25% (4) during the dry season (May 1- September 30) will be done. There is a possibility of no flow to the final vault during the dry season, and if that is the case, sampling will be limited. The criteria described in Dr. Homer's report will be used to determine sample analysis and is summarized in Figure 1. Sampling of non-storm discharges to the treatment system will be developed as operational experience is gained. • Sampling Equipment: Three samplers containing the following components have been installed in the above designated sampling locations: • ISCO 3700 series sampler • ISCO 3230 flow meter • ISCO rain gage • portable computer for data transfer • ISCO flowlink software Expansion rings have been installed at the two inflow sites in the bottom of the outlet pipe to fix the bubbler line in place. The sampler suction head has been anchored to the bottom of the channel. Flow measurement are based on Manning's equation for open-channel flow. Weirs are being ordered and will be installed in the two inflow sampling locations for more accurate flow measurement. At the effluent vault, the bubbler has been installed on the upstream side of the stop-log weir in the outfall structure. Flow measurement will be based on an empirical broad- crested weir equation. The sampler suction head has been installed on the wall upstream of the weir. Experience with this system and its response to storm run-off will provide important information for "fine tuning" the sampling equipment. It is our understanding that this system has not been integrity tested. If the plastic covering the stop-logs is damaged or incompletely covers the logs, seepage through the logs will occur and inaccurate flow-data will result. Your project team needs to complete this as soon as possible. • Sampling Procedures: Flow-weighted composite sampling will be done on each sampling occasion. The monitoring system will begin operating at the onset of runoff during a storm event at the two inflow sites. A flow-weighted sample (300 ml) will automatically be taken every time 1,500 gallons has passed down the pipe. The samplers are programmed to fill two one-gallon containers assuming a six-hour storm event generates 100 gpm of run-off. Due to the amount of storage available in the lake�predicting when run-off will appear as effluent at the vault will be difficult and will require some operating experience to determine. Therefore, co-ordinating inflow and outflow sampling will not be meaningful and performance will be based on long-term data. During the rainy season it is also expected that the vault will be discharging on a semi-continuous basis not on a storm event. Sampling during this season will be as described by Dr. Horner on pages 11-12 of the report unless operating experience suggests otherwise. Composite sampling will be continued as long as flow is uninterrupted for no more than 2 hours. Sampling shall occur through the entire event if the total flow duration is six hours or less. If runoff continues for longer than six hours, sampling will continue until the storm ends or at least another six hours. Once experience with the treatment system is gained, the best method to produce representative data will be used. • Sample Analysis: The anal) sis to be run on the samples include: �• Total suspended solidF • Total phosphoru-z Metals: Copper, lead, zinc There will be no other metals analysis done. This site is a training center, hence no heavy industrial activity which could introduce pollutants into the storm water is expected. All maintenance shops are located inside and only minimal painting for building and grounds maintenance, which could contain heavy metals, takes place outside. Analysis for past pesticide use will not be included with this study due to the inability to obtain this data. Analysis for pesticides currently used on the site will be done on an intermittent basis. For the first 3 sample sets collected, the following analysis will also be run: • Total Kjeldahl nitrogen • BTEX (benzene, toluene, ethylbenzene, and xylene) Due to the large number of water fowl present, nitrogen levels may be elevated. When possible, a grab sample at the discharge during the first hour of each event will be taken by a Environmental Operations Waste Water Treatment operator and analyzed for fats, oils and grease (FOG). Following all the sample analysis the Boeing Environmental Lab will clean the sample containers using their standard lab practices. All samples will be handled using the appropriate chain of custody forms. The Renton Division Environmental Lab is an accredited environmental laboratory and as such follows all the QA/QC requirements of such facilities. • Data Analysis/Interpretation Data analysis will be performed throughout the program and further developed as the sampling program proceeds. At a minimum, annual (water-year) pollutant loadings will be estimated into and out of the treatment system will be estimated. The treatment system effectiveness will then be determined and the effectiveness of meeting the code modification conditions will be addressed. The code modification conditions are based on the following loading reductions: • TSS and Pb: 67% minimum in any water year and 77% average over the successive water years. • Cu and Zn: 48% minimum and 58% average • TP: 32% minimum and average • FOG: never exceeding 15 mg/L in effluent grab The impact of aeration, water recirculation and water make-up will be evaluated during periods when these actions take place and will be compared to other periods. Trends associating the system operation with performance will be noted and operating actions which improve performance will be identified. As we develop experience with this system, changes in operations may occur. These changes will be communicated to the appropriate parties at that time. Action Items: Several items mentioned above and listed below need action by your team before we are able to evaluate the performance of this system. a) Integrity test the final vault to ensure there is no leakage through the stop logs which will skew the results of the study. b) Cleaning all catch basins such that stormwater run-off can reach the pond rather than pooling in the street. c) Adjusting the sprinkler system in the parking lots to minimize flow into the pond. Please provide me a schedule for completing these items and keep me posted on the progress of these items, as they impact our sampling plan. If you have any questions or require any additional information please contact me at 965- 2703. Doris S. Turner Environmental Engineer Water Quality, Renton SHEA R-1150/MS 63-41 FIGURE 1 LONGACRES SAMPLING GUILDLINE 72 NO 48-72 NO LT 48 HOURS HOURS HOURS DRY DRY DRY YES YES GOAL: EXCEED YES 12 WET WEATHER 0.72" ANALYZE SAMPLE RAINFALL 4 DRY WEATHER *ANALYZE SAMPLE ONLY IF NO CANNOT MEET # OF EVENTS 0.24" - No EVALUATE 0.72" (ANALYZE ONLY IF CONCERN RAINFALL IN MEETING CRITERIA) YES RAIN YES INTENSITY ANALYZE SAMPLE )0.036"hr NO 0.012" - 0.036" NO EVALUATE RAINFALL (ANALYZE ONLY IF CONCERN INTENSITY IN MEETING CRITERIA) YES STOR DURATION YES 6-17hrs DRY ANALYZE SAMPLE 10-30hrs WET EVALUATE DT-02A(ENV) No (ANALYZE ONLY IF CONCERN IN MEETING CRITERIA) BOEING CUSTOMER SERVICE TRAINING CENTER STORMWATER QUALITY MONITORING AND ASSESSMENT PROGRAM Prepared for Sverdrup Corporation By Richard R. Horner 230 NW 55th Street Seattle, Washington 98107 782-7401 October 1992 Richard R. Horner, Ph.D. Environmental Engineering and Science R E C E I V E D 0 C T I '1 1992 230 N.W. 55th Street Seaale, Washington 98107 SVERDRUP (,ORP (206) 782-7401 October 14 , 1992 Mr. Andrew Clapham The Boeing Company P. O. Box 3707, MS 6Y-50 Seattle, WA 98124-2207 Dear Andrew: Enclosed is a new draft of the Longacres site stormwater monitoring plan incorporating the revisions to which we agreed during our telephone conversation on October 12 . I will be glad to consider any additional comments that you may have and to make further changes accordingly. I will also be pleased to assist you further in any way that would be helpful as you finalize your site plans and construct and begin to operate the system. Feel free to contact me directly or through Sverdrup any time. Sincerely, Richard R. Horner cc: Mr. J. David Benson INTRODUCTION This report presents a comprehensive Stormwater Quality Monitoring and Assessment Program for the Boeing Customer Service Training Center (CSTC) to be constructed on the site of Longacres Racetrack in Renton. The program is based on and designed to satisfy the code modification/alteration conditions placed on the stormwater management system, as stated by the City of Renton in Ron Straka's memorandum of May 20 , 1992 . The program encompasses monitoring of stormwater facilities for water pollutant removal effectiveness. It thus addresses monitoring of flows entering and exiting the treatment system, which will be performed external to the system . It does not incorporate monitoring of the long-term development of the wetland complex, nor of the trophic state and related conditions within the lake. However, the program has been made as consistent as possible with the anticipated monitoring internal to the system for cost savings. Also, the program does not deal with receiving water monitoring. In the usage here the term "monitoring" incorporates sample collection, laboratory analysis , and analysis and interpretation of the resulting data. After the monitoring program objectives are stated, the sections under the heading Sampling Plan provide recommendations on where, when, and how sampling should be performed. Each of these sections is divided into two subsections, the first a discussion of the considerations that went into the recommendations, followed by a concise summary in bold type of the procedures to be followed. A reader who is interested only in what tasks should be performed can proceed directly to the summaries. Following the Sampling Plan come sections presenting the Sample Handling and Analysis Plan and Data Analysis and Interpretation Plan, which are arranged in the same way with discussions followed by concise summaries . MONITORING PROGRAM OBJECTIVES The monitoring program design is based on achieving the following objectives. These objectives are stated first in general and then in somewhat more specific terms. 1. To develop a basis for comparing stormwater treatment system performance to the expected performance of the system required by the Renton code (i . e. , to test compliance with the code modification/alteration approval conditions) . To express treatment system performance in terms of mass loading reductions of index pollutants between their entrance to secondary ponds and exit to the receiving water; the standards of comparison will be the minimum and median loading reductions in the treatment system 2 relative to those expected in the code system, according to estimates presented in the documentation prepared to obtain the approval. 2 . To provide data that can help guide treatment system operation in order to maximize the achievement of performance and other objectives. To provide feedback on how such actions as water recirculation, aeration, and makeup are affecting system performance, so that these actions can be regulated in the most advantageous manner. 3 . To expand the knowledge base on stormwater treatment in order to increase the ability of Boeing personnel and others to specify these systems in the future. To exploit the opportunity to gather data on the performance of a stormwater treatment system that includes wet ponds and a constructed wetland/lake system; to relate that information to design and operating conditions with the goal of learning how best to specify these facilities. SAMPLING PLAN SAMPLING POINTS Discussion The code modification/alteration approval was based on the proposed treatment system's exceeding the code-based system in reducing the entering pollutant mass loadings. Demonstrating compliance with this condition, and thereby achieving Objective 1, requires a sampling plan designed to produce mass loading estimates at entrance and exit points. The entrance and exit points of interest are, respectively, the inflows to the two secondary ponds , after the confluence of discharges from the primary vaults, and the system discharge at Springbrook Creek. It is proposed that inflow sampling be performed at the entrances of the secondary ponds, rather than upstream of the primary vaults for two reasons. First, sampling prior to the four vaults would double the monitoring burden and equipment requirements . Second, while the vaults will remove larger solids, no credit was taken for this treatment in the analysis performed to justify the code modification/alteration approval. The pollutant mass loading will be affected by any runoff that enters the system as overland flow, rather than piped to the secondary ponds , and by external makeup water that is added to the treatment system (e. g. , from groundwater) . Extraneous overland flow will be very small and will be neglected. However, 3 r makeup water could be a more significant factor. It will accordingly have to be sampled, and represents an influent sampling point additional to the two secondary pond inflows . Since makeup water will only be added in the dry season, when the ponds are normally not receiving flow, sampling equipment can be transferred from one of the pond stations when necessary to monitor makeup water. Summary of Sampling Points Sampling should be performed at the following points: Inflows--Two secondary pond inflows after confluence of vault discharges; Makeup water (if and when added) ; outflow--Treatment system discharge to Springbrook Creek. SAMPLING SCHEDULE Discussion Length of Monitoring Program-- The monitoring schedule involves setting the times for sampling to commence and cease and how to allocate the sampling effort during the overall period. It is recommended that sampling begin immediately upon occupancy and startup of the CSTC treatment system. It is reasonable to suppose that treatment effectiveness would improve as vegetation matures, a factor that is recognized by the City of Renton (Straka, personal communication) . Therefore, a record should be kept of observable changes in the system, especially of the vegetation community, in order to interpret any variations in performance noted in the early period of operation. This record will result from any formal monitoring of the development of the wetland/lake system. In the event that no comprehensive monitoring of this type is performed, overall vegetation coverage and density and the approximate abundance of the individual species in each part of the system should at least be noted on approximately the same date or dates each year. It is recommended that monitoring proceed for two full water- years following treatment system startup. With the water year running October 1-September 30 , the total monitoring period thus is likely to extend between two and three years . This schedule is recommended in consideration of the pronounced seasonality of precipitation in the region and the desirability of having pollutant mass estimates from more than one full hydrologic cycle. Two water-years of data will provide some insurance against relying for conclusions on a meteorologically atypical year. The period between system startup and the beginning of the first water-year will allow for maturing of the vegetation 4 r through one growing season before water-year pollutant mass calculations are made. It is proposed that the Boeing Company and the City of Renton negotiate further monitoring at the conclusion of the second full water-year and the presentation of its results. It is suggested that monitoring be suspended at that point under the following conditions: (1) the system met or exceeded the minimum performance levels in both years, and the average performance over the two years was at least at the median expected from a system meeting the Renton code (see Data Analysis and Interpretation Plan) ; (2) there are no significant changes in the runoff delivery to the system, nor in the treatment system itself; and (3) the system is maintained as designated by Boeing's maintenance manual. In the event that the system met the minimum requirements in only one of the two years or failed the two-year average requirements, an additional water-year of monitoring should be performed. If the system does not meet the minimum and average performance requirements in the second and third years, it is recommended that diagnostics be performed to determine probable causes of failure and corrections be made. Then, the process of two water- years of performance monitoring should be repeated. Once the system's ability to meet requirements is demonstrated in two successive water-years, it is suggested that further monitoring be required only when the site develops further, or the runoff is otherwise significantly changed; major revisions are made in the treatment system; or maintenance fails to meet maintenance manual standards . Allocation of Sampling Effort-- Establishing the masses of pollutants entering and exiting the treatment system requires estimates of pollutant quantities from representative flow intervals extrapolated to a longer period such as a season or a year. Making these estimates requires data on flow quantities and pollutant concentrations, with loading for an interval being the product of flow over the interval and average concentration during that time. Flow should be continuously recorded with automatic equipment throughout the year, when any flow is occurring or could occur, at each sampling point. It is impractical to sample and analyze every flow event to determine average pollutant concentrations. Therefore, events to be monitored must be carefully chosen to gain information of the highest quality for the budget expended or, conversely, to minimize the cost of obtaining information of the quality needed. The most fundamental consideration is to allocate effort to flow events that appropriately represent the full water-year. For proper representation, sampling should be performed not only during and after storms but also during occasions when any 5 ( I surface baseflow, irrigation runoff, or makeup water enters the system. The recommended sampling effort allocation will be described for the following types of flow events: (1) "wet-season" storms, (2) "dry-season" storms, and (3) "non-storm" events . The wet season is defined as October 1-April 30 and the dry season the remainder of the year. Non-storm events are considered to be episodes of surface baseflow, irrigation runoff and makeup water addition. It is assumed that surface baseflow will normally not enter the treatment system, and the use of irrigation and makeup water is not settled as yet. Nevertheless, including this category will allow planning for any eventuality. The Seattle area receives approximately 90 recorded rainstorms in an average year. It is recommended that the monitoring program have the general goal of collecting a composite sample from all of those storms, until the annual quota is attained, but of proceeding to analyze only a fraction of the samples collected, selected on the basis of definite criteria. Even with this goal, mistiming and equipment failures will reduce the pool of available samples for making pollutant loading estimates. It is proposed that targets for complete laboratory analysis be set at 10-15 storm events per year, approximately one q r _ex c,f which should be allocated to dry-season (May 1-September 30) storms Special effort should be made to monitor any of the quite rare snow-melt events that occur. Criteria for selecting rainstorm samples for analysis are (adapted from U. S. Environmental Protection Agency 1991) : 1. Antecedent dry period--preferentially select events preceded by 72 hours or longer without rainfall exceeding 0. 1 inch, next those preceded by at least 48 hours of such conditions; 2 . Total rainfall--analyze samples from any storms successfully sampled (defined under Sampling Procedures below) when the precipitation total is more than 150 percent of the mean for the area (0 . 72 inch) ; otherwise, give preference to events with rainfall totaling at least 50 percent of the mean (0. 24 inch) ; 3 . Rainfall intensity--analyze samples from any storms successfully sampled when the average intensity is more than 150 percent of the mean for the area (0 . 036 inch/hour) ; otherwise, give preference to events with rainfall totaling at least 50 percent of the mean (0 . 012 inch/hour) ; 4 . Event duration--preferentially select events with durations between 50 and 150 percent of the mean for the area (10-30 hours in the wet season and 6-17 hours in the dry season) . 6 ♦ r Non-storm flows (both inflows and the treatment system effluent) should be monitored during a 24-hour period (see Sampling Procedures below) whenever conditions have changed significantly relative to previous monitoring occasions or, if conditions change little, on a periodic schedule. Examples of modified conditions include: Change in flow rate or total volume; The occurrence of a fertilizer application on irrigated landscape; Spillage of a polluting material that enters non-storm runoff. If conditions are fairly constant, it is then recommended that non-storm flows be sampled biweekly. Summary of Sampling Schedule Begin sampling immediately after treatment system startup and continue until two full water-years have passed. Observe treatment system development, especially the vegetation community, preferably in conjunction with comprehensive monitoring within the lake/wetland system (for this purpose, record especially overall vegetation cover and density and abundance of individual species in each portion of the system at the same time(s) each year) . At the end of the second water-year Boeing and the City of Renton should evaluate and negotiate the need for further monitoring on the following basis. suspend monitoring at that point under these conditions: (1) the system met or exceeded the minimum code approval requirements in both full water-years, and its average performance in the two years met or exceeded the median levels expected in a code-based system (see Summary of Data Analysis and Interpretation) ; (2 ) there are no significant changes in the runoff delivery to the system, nor in the treatment system itself; and (3) the system is maintained as designated by the maintenance manual. If system met the minimum requirements in only one of the two years or failed the average requirements, monitor for an additional water-year. If it fails to meet minimum and average requirements in the second and third years, perform diagnostics to determine probable causes of failure and make corrections. Then, repeat the process of two water-years of performance monitoring. Once the system's ability to meet requirements is demonstrated in two successive water-years, reactivate monitoring only if there are significant changes in the CSTC site or the treatment system or if the system maintenance does not meet city standards. 7 y Automatically measure flow continuously at each sampling point. Establish a goal of collecting a composite sample of every storm event, but only analyze 10-15 sample sets per year, allocated approximately 75 percent to the wet season (October 1-April 30) and 25 percent to the dry season (May 1-September 30) . Select samples for analysis until quotas are met according to the following guidelines: 1. If the event was not sampled successfully (as defined later under Sampling Procedures) , discard the sample and do not analyze. If it was sampled successfully, go to 2 . 2 . If the event is snow-melt runoff, analyze the sample. If the event was a rain storm, go to 3 . 3 . If the event was preceded by at least 72 hours with no more than 0. 1 inch of rain, go to 4 . If preceded by 48- 72 hours with no more than 0 . 1 inch of rain, go to 4 , unless the 48-72 hour antecedent dry period is over- represented among the samples already analyzed and it is expected that adequate opportunities will occur before the end of the water-year to obtain samples meeting the 72-hour criterion (in that case, discard the sample) . If the event was preceded by less than 48 hours with no more than 0. 1 inch of rain, go to 4 only if there is concern that sufficient samples meeting the 48-hour criterion can be obtained during the remainder of the water-year (otherwise, discard the sample) . 4. If the storm total rainfall exceeded 0 . 72 inch, analyze the sample. If the total was 0 . 24-0.72 inch, go to 5, unless that rainfall total is over-represented among the samples already analyzed and the quota is very close to being met (in that case, discard the sample) . If the event had less than 0. 24 inch of rain, go to 5 only if there is concern that sufficient samples meeting the 0 .24-inch criterion can be obtained during the remainder of the water-year (otherwise, discard the sample) . 5 . If the average rainfall intensity exceeded 0 . 036 inch/hour, analyze . the sample. If the intensity was 0. 012-0. 036 inch, go to 6, unless that intensity is over-represented among the samples already analyzed and the quota is very close to being met (in that case, discard the sample) . If the event had intensity of less than 0 . 012 inch/hour, go to 6 only if there is concern that sufficient samples meeting the 0. 012-inch/hour criterion can be obtained during the remainder of the water-year (otherwise, discard the sample) . 6. If the storm was 6-17 hours in length in the dry season or 10-30 hours in other months, analyze the sample. If 8 the duration was outside the seasonally appropriate range, analyze the sample only if there is concern that sufficient samples meeting the duration criterion can be obtained during the remainder of the water-year (otherwise, discard the sample) . Sample non-storm discharges to the treatment system (e. g. , surface baseflow, irrigation runoff, makeup water) and the system effluent whenever discharge conditions (flow or water quality) may have changed significantly or, if conditions are relatively constant, at least every two weeks while the discharge continues. SAMPLING EQUIPMENT SPECIFICATIONS Flow Measurement The flow meter should be programmable and capable of performing the following functions: (1) monitoring and recording signals from the precipitation gage and providing information on the date, duration, and amount of rainfall; (2) measuring and recording the runoff flow rate and providing information on the event hydrograph and total runoff volume; (3) activating the sampler according to a programmed rainfall amount or level rise; (4) signaling the sampler when a flow-weighted sample is to be taken. It is preferable that the flow meter be used with a weir or flume for the most accurate flow measurement, but it should be capable of being programmed with an equation to relate flow with level if the configuration does not permit use of a control device. The flow meter should include a plotter/printer. The flow meter should be equipped with the necessary software to transfer data into computer files . The transfer can be accomplished either on-site with a portable computer or via telephone lines using an internal modem. The flow meter should be from the ISCO 3200 series or equivalent, which includes ultrasonic, submerged probe, and bubbler tube level measurement types. The ISCO 3230 bubbler tube meter or equivalent is particularly recommended for applications of this type. ISCO Flowlink software or equivalent and either a portable computer or the optional internal modem should be supplied for data transfer. Sample Collection The sampler should be programmable and fully compatible with the flow meter. It should be capable of sampling according to both flow-weighted and fixed time interval programs for greatest flexibility. It is preferred that the entire monitoring system be operated on AC electric power and that the sampler be refrigerated to preserve samples best. Should a sampler with 9 that more costly feature not be selected, the sample bottle compartment should have sufficient space for adding ice for preservation. The sampler. should be from the ISCO 3700 series or equivalent. The specific selection from the series depends on the range of uses anticipated for the equipment in this and other monitoring efforts. A sampler that is limited to flow-weighted composite sampling will be adequate for the program described here but may not have sufficient capability to serve other purposes. Precipitation Measurement The rain gage should be fully compatible with the flow meter and be capable of signaling each 0 . 01 inch of rainfall. ISCO markets such a gage for use with its flow meters. Summary of Sampling Equipment Specifications At least three of the following systems, or equivalent, should be provided. Three systems will serve both secondary pond inlets and the treatment system discharge. Purchasing an additional system would provide a spare to serve during a breakdown and would allow sampling intermittent inflows without moving one of the primary systems. ISCO 3230 flow meter with either internal modem and telephone connection or a separate portable computer for data transfer; Weir or flume control device for flow measurement, if the configuration permits; ISCO Flowlink software; ISCO 3700 series sampler, preferably refrigerated; ISCo rain gage; and AC power connection. SAMPLING PROCEDURES Discussion Pollutant loading estimation demands determining the event-mean concentrations (EMCs) of pollutants of interest. True EMCs can be measured only in samples composited over time during the event by adding sample aliquots in volumes proportional to the flow rate at the time of sampling. Therefore, all sampling in this program will be directed at obtaining flow-weighted composites . 10 It is commonly observed in many areas that the bulk of pollutants enter runoff early in the event as surfaces are washed off during the initial flow. This "first-flush" period can be as short as minutes . With the Pacific Northwest's long, low-intensity, and sometimes nearly continuous winter rainfall, the first flush is less prominent than in most of the nation. Still, it is not at all uncommon, especially following the long summer drought. Therefore, it is necessary to include the early part of the runoff period to be sure of having a representative sample. Another consideration is the duration of sampling. Storms in this area routinely extend for many hours, and excessive sampling lengths could exceed sample holding time limits for laboratory processing or even sample container volume. While the equipment is automatic, it frequently needs human attention that is hard to provide over a very extended period. On the other hand, to be representative the sample must be composited over a. sufficient period to yield a good estimate of the true EMC. Timing of sampling is also complicated by the frequently intermittent nature of precipitation and consequent substantial variation in runoff within the event. Some guidelines must be set to regulate this feature of sampling, and there is little objective basis to do so. The following guidelines are proposed for this program: i (1) the monitoring system must be operating at the onset of runoff; (2) sampling should continue as long as flow is interrupted for no more than two hours and the personnel can assure proper equipment operation, up to a maximum of 24 hours ; (3) if flow is interrupted for more than two hours, sampling should end; (4) sampling should cover the entire event if the total flow duration is six hours or less and at least half of the maximum 24-hour period, or until the storm ends. Another sampling complication is the lag period that sometimes results from ample storage before runoff appears at the sampling point. This consideration is especially operative at the CSTC site, where the lake offers days of storage before entering runoff would appear in the effluent. Even the primary vaults will provide significant storage. Therefore, the concept of coordinated inflow/outflow sampling is meaningless in this case; performance can only be judged by comparing long-term, cumulative pollutant mass loadings entering and leaving the system. This situation of long lags offers the advantage of more predictability in sampling. With experience, personnel will be able to form a good idea of when runoff will first appear at the secondary pond inlets after the beginning of precipitation, so that monitoring systems can be checked to ensure reliable operation. The lake and associated downstream channel system are likely to operate in a semi-continuously flowing mode during the wet season, with flow patterns largely divorced from storm activity. Monitoring in this case will not really be on an event basis. If and when this pattern proves to be the case, it is suggested that the wet season quota of composite samples be collected by 11 operating the equipment for a series of 24-hour periods timed to cover relatively high and lower flow periods. These periods should be well distributed through the October 1-April 30 span. If entirely uniformly spaced, they would occur about every 15 days to sample the approximately 14 wet-season target storms. Absolutely uniform distribution is not necessarily recommended, considering that flow patterns will probably not be uniform; and this figure is offered only as a rough guide. Again experience with the system will be a guide for the assigned personnel on how to time the sampling. As reasoned later in the discussion of the Sample Handling and Analysis Plan, one analysis recommended is for oil and grease. The oil and grease analysis can only be performed in a discrete grab sample, and not in a composite, because of the petroleum' s tendency to adhere to any surface that it contacts . Accordingly, it is recommended that a grab sample be taken in the containers specified under Sample Handling at the treatment system discharge point during the first hour of any runoff event when sampling personnel are on the site. Because personnel will rely on automatic equipment and will not always be present, the number of opportunities will be more limited for grab than for composite sampling. Therefore, all samples taken for oil and grease should be analyzed. Summary of Sampling Procedures Perform flow-weighted composite sampling at each sampling point on each sampling occasion. , -Always set the monitoring system to begin operating at the onset of runoff. Continue composite sampling as long as flow is interrupted for no more than two hours and the personnel can assure proper equipment Dperation, up to a maximum of 24 hours. Und composite sampling if flow is interrupted for more than two hours. Sample through the entire event if the total flow duration is six hours or less; if runoff continues longer than six hours, sample Qntil the storm ends or at least another six hours. Employ experience with the treatment system as it develops to time composite sampling in the best way to produce representative data. If the lake system discharges semi-continuously during the wet season, take a series of 24-hour composite samples timed to cover relatively high and lower flow periods. Distribute these periods through the October 1-April 30 period to provide the most thorough representation of wet-season pollutant loadings. 12 Collect a discrete grab sample at the discharge during the f irst hour of each event when sampling personnel are at the site, and analyze all such samples for oil and grease. SAMPLE HANDLING AND ANALYSIS PLAN RECOMMENDED ANALYSES Discussion The principal recommended analyses are the pollutants that were used as performance indices in the application for the code modification/alteration. These pollutants include one measure of particles (total suspended solids, TSS) , one measure of nutrient pollution (total phosphorus, TP) , and three heavy metals (copper, Cu; lead, Pb; and zinc, Zn) . These analyses will be the basis for cumulative pollutant loading comparisons between the entrance and exit of the treatment system. �n�r nee —'> e-xkt" Many quantities can be measured in water samples and contribute information varying in its value for achieving the stated objectives. Among these many possibilities, just one additional analysis, for oil and grease, is recommended to add important documentation concerning the system's performance. One issue in the code modification/alteration request was the omission of coalescing plate oil/water separators in the treatment system. These separators generally have the ability to reduce oil and grease concentrations to no more than 15 mg/L. There is some evidence (Horner 1988) that vegetated treatment systems can achieve lower concentrations, and data on the ability of this system to do so would add to its acceptance. Boeing has identified certain materials that have been used at the Longacres site over the years and have the potential to pollute water. These materials include fertilizers, materials containing metals, pesticides, and volatile solvents. Certain measures will be taken to avoid water pollution by substances associated with these materials, and their appearance in receiving waters is not expected. Adding analyses to this program that identify any such appearance will demonstrate their absence from storm water and the site effluent or, if they appear, permit the institution of additional remedial measures to remove them. Additional analyses should be specified on the basis of the particular materials used on the site. These analyses should include total Kjeldahl nitrogen (TKN, to represent fertilizers, along with the total phosphorus analysis already specified) ; metals known to be on the site (in addition to the copper, lead, and zinc already specified) ; pesticides that have been applied in the past; and the solvents benzene, toluene, ethylbenzene, and xylene. These analyses should be performed on at least the first three sample sets collected. The analysis should continue for any substance that is above detection (for 13 extra metals, pesticides, and solvents) , or significantly above a background level for the area (for total Kjeldahl nitrogen) , until remediation reduces the occurrence below these levels in three successive sample sets. Summary of Recommended Analyses Analyze in all composite samples--Total suspended solids; Total phosphorus; Metals copper, lead, and zinc. Analyze in at least the first three composite sample sets collected; continue to analyze when the event mean concentration is above detection (or significantly above local background level for total Rjeldahl nitrogen) until three successive samples have EMC below this level-- Total Rjeldahl nitrogen Additional metals found on-site Pesticides previously used Benzene, toluene, ethylbenzene, xylene Analyze in grab samples-- oil and grease. SAMPLE HANDLING Discussion Sample handling guidelines have been assembled in various publications of monitoring methods, in particular the widely used handbooks by the American Public Health Association (1989) and the U. S. Environmental Protection Agency (1983) . These guidelines were drawn together in a regional guidance manual prepared for the Puget Sound Estuary Program (Tetra Tech, Inc. , University of Washington, and Battelle Pacific Northwest Laboratories 1988) , which is the basis for the recommendations made here. These references also provide more detail. In addition to these provisions, samples intended for pesticide and sovent analysis should follow procedures specified by the U. S. Environmental Protection Agency (1986) . Summary of Sample Handling Prepare all equipment that will directly contact samples by washing with phosphorus-free detergent, rinsing with tap water, and rinsing three more times with ultrapure deionized water. 14 Following the water rinses, prepare all equipment that will directly contact samples intended for TP and TKN analysis by acid washing with sulfuric acid. After acid washing, rinse completely at least six times with ultrapure deionized water. Following the water rinses, prepare all equipment that will directly contact samples intended for metals analysis by additional acid washing. Fluoropolymer bottles, the best containers for metal samples, should be soaked in hot (60-95 C) concentrated nitric acid for 24-48 hours, followed by 24 hours in hot, dilute high purity nitric acid. Soak polyethylene and glass equipment in 6 Normal nitric acid for one week and then rinse thoroughly with ultrapure deionized water. Prepare all equipment that will directly contact samples intended for pesticide and solvent analysis and handle the samples as specified by the U. S. Environmental Protection Agency (1986) . Label sample bottles at or before the time of collection with at least the following information: station, date, time, collector's name, any preservative added, and the analyses to be performed. Maintain a chain-of-custody record to track possession of every sample as it travels from collection through analysis. Follow these additional sample handling guidelines for the minimum sample volumes to be provided to the laboratory, the sample containers, preservation, and holding times: Min. Vol. Holding Time Analysis mL Containera Preservation Prefer. Max. TSS 1000 P, G 4 C refrig. 7 days 7 days TP 125 P, G H2SO4 to pH < 2 48 hr. 28 days 4 C refrig. TKN 1000 P, G H2SO4 to pH < 2 48 hr. 28 days 4 C refrig. Metals 125 P, G ultrapure HNO3 6 mo. 6 mo. to pH < 2 Oil + Gr. 1000 Brown G H2SO4 to pH < 2 7 days 28 days 4 C refrig. a P--Plastic (polyethylene, polypropylene, or fluoropolymer; the latter is preferred for metals) ; G--Glass. 15 ANALYTICAL METHOD SPECIFICATIONS Discussion The same references named above under sample handling are the basis for the recommended methods and provide complete details on performing the analyses. These analyses should be performed in a laboratory accredited by the Washington Department of Ecology, a status held by the Boeing laboratory. Summary of Analytical Method Specifications Use the following analyses to achieve the detection limits stated. Perform these analyses in the Washington Department of Ecology-accredited Boeing laboratory. Analysis Method Detection Limit TSS Gravimetric 1 mg/L TP Ascorbic acid reduction 5 gg/L (preferably automated) following persulfate digestion TRN Automated phenate 50 gg/L Pb Graphite furnace 1 µg/L atomic absorption Other Inductively coupled 6 µg/L metals plasma Oil + Grease Infrared 1 mg/L spectrophotometric Follow the specifications of the U. S. Environmental Protection Agency (1986) for the analysis of pesticides and solvents. QUALITY ASSURANCE/QUALITY CONTROL PROVISIONS Discussion The effectiveness of any monitoring effort depends on its quality assurance/quality control (QA/QC) program. The QA/QC program Provides quantitative measurements of the "goodness" of the data. The references listed above again provide the basis and additional detail. The following definitions and acceptance criteria apply to QA/QC: 16 Field replicates--Separate samples collected simultaneously at the identical location and analyzed separately (used to assess total sample variability) ; Laboratory replicates--Repeated analyses performed on the contents of a single sample bottle (used to assess variability due to laboratory procedures; replicates in general are used to assess precision) ; Find and correct the problem and repeat the analyses if the relative percent difference (RPD) is outside the control limits established by the laboratory, where: RPD = (Cl - C2) x 100/ ( (C1 + C2) /2) . C1 and C2 are the larger and smaller values, respectively. Calibration (control) samples--Samples prepared from ultrapure deionized water that contains a known concentration of a specific substance; Find and correct the problem and repeat the analyses if the deviation from true value is outside the control limits established by the laboratory. Blanks--Samples prepared from ultrapure deionized water, perhaps with analytical reagents added, to represent zero concentration of a specific substance (used to assess contamination introduced in the laboratory) ; Rerun affected samples if the concentration measured in a blank exceeds the method detection limit. Spiked samples--Samples prepared by adding a known concentration of a specific substance to environmental samples; Find and correct the problem and repeat the analyses if the percent recovery (%R) is outside the control limits established by the laboratory, where: %R = (S - U) x 100/Csa• S = measured concentration in spiked sample; U = measured concentration in unspiked sample, and Csa = actual concentration of spike added. Summary of QA/QC Provisions General-- Use the acceptance criteria stated above. 1 -7 Randomly select 10 percent of each type and location of sampling for field replication. Randomly select 10 of the samples for laboratory replication. TSS-- Check balance calibration monthly and oven temperature daily. Perform annual preventive maintenance checks on balances. Run USEPA control suspensions of known concentration at least semiannually. TP and TKN-- Run a calibration curve with a blank and standards at '0 .2, 0 . 5, and 1. 0 cu (cu = upper limit of expected concentration range) with each batch (defined as no more than 20 samples) for TRN (also at 0.35 and 0.75 cu for TP) . The entire range of sample concentrations must be included in the calibration curve. Run control samples at 0.2 and 0. 9 cu with each batch. Run blanks at the beginning and end of each batch. Run one spiked sample per batch. Metals-- Run at least one blank and one spiked sample per batch. For Pb, run the method of standard additions if necessary. Run certified control samples of known concentration at least semiannually. Oil and grease--No special provisions. Pesticides and solvents--Follow procedures specified by the U. S. Environmental Protection Agency (1986) . 18 DATA ANALYSIS AND INTERPRETATION PLAN Discussion Data analysis should be performed with the monitoring program objectives clearly in mind. Relative to Objective 1, the treatment system's performance in reducing pollutants in the effluent will be gaged primarily by comparing the actual reductions in inflow cumulative mass loadings achieved with the reductions expected in a system designed according to the Renton code. The proposed standards for documenting compliance with the code modification/alteration approval conditions are that the minimum system performance meet or exceed the minimum expected form the code-based system in each of two water-years, and that the average performance for the two years be at least at the level of the code-system median levels. On this standard the relevant loading reductions that must be attained are: TSS and Pb--67% minimum in each water-year and 77% average in two successive water-years; Cu and Zn--48% minimum and 58% average; TP--32% minimum and average. Cumulative loading, L, for the time interval [T1, T21 is the integrated product of the flow rate, q(t) , and pollutant concentration, c (t) , functions over the interval: T1 L = q(t) c (t) dt T2 In practice, estimation of loading requires summing up products of total flow volume and concentration existing for subintervals over the full period of interest. If there is a continuous flow record, as would be the case if the program recommended here is adopted, the flow volume for each subinterval is obtainable with only a small measurement error. However, as in this case, concentrations are normally available only as event means and only for representative, but not all, events during each subinterval. In this situation some estimator of c(t) must be used to characterize the entire subinterval. Four fundamentally different ways exist to make this concentration estimate: (1) break subintervals at the midpoints between events when concentrations were measured and use each measured EMC to characterize its subinterval; (2) break subintervals at the points where concentrations were measured and linearly interpolate between the EMCs measured at each end of the subinterval to select an estimator for the subinterval; (3) estimate c (t) as a function of q(t) by statistically regressing 19 measured EMC values against average flow rates (or total flows) existing during the periods when the EMCs were determined, and using the regression equations to estimate concentration from flow records for a series of defined subintervals; and (4) performing the same regression as just described but using a logarithmic transformation of the concentration and flow variables. These methods are illustrated in a paper by Reinelt and Grimvall (in press) . If a reasonably strong association exists between concentrations and flows, the third and fourth methods have advantages in yielding more accurate loading estimates if extreme runoff events occur, assuming they are at least partially represented in the monitoring record. Therefore, correlation analyses should be performed with both untransformed and logarithmically transformed data. Whichever gives the higher correlation, if the correlation is statistically significant, should be used as the basis for a regression to obtain an estimating equation. In any case when neither correlation is significant, method 2 (linear interpolation) should be used to estimate loadings. An additional standard of performance is for the treatment system to discharge effluent that never exceeds 15 mg/L of oil and grease. Beyond treatment system performance demonstration, Objective 2 concerns relating performance to system operating 'actions in order to evaluate their efficacy. For this purpose loadings should be estimated as described above for periods (some fraction of the full water-year) when such actions as aeration, recirculation, or makeup took place. Treatment performance should be compared between these periods and when no such actions were taken, as well as between times when different strategies were applied for a given action. Note should be taken of operations that were associated with the best levels of performance. These operating strategies should be repeated and monitored further to confirm or refute their influence on performance. Those confirmed as effective should be installed as routine practices . Summary of Data Analysis and Interpretation Estimate annual (water-year) pollutant loadings entering the system at the secondary pond inlets and leaving at the Springbrook Creek discharge point. Compute these estimates by summing products of flow volumes and pollutant concentrations for a series of time subintervals making up the water-year. Use the continuous flow record to obtain flow volumes. Use the technique described in the following paragraph to obtain pollutant concentrations. Perform statistical correlation analyses associating EMCs and the flow volumes during the respective periods when EMCs were determined, as well as between logarithmically transformed EMCs 20 and flow volumes. Use whichever gives the higher correlation, if the correlation is statistically significant, as the basis for a regression to obtain an estimating equation for concentration. Apply the regression equation to estimate concentrations for the series of time subintervals. In any case when neither correlation is significant, obtain concentration estimates as follows: Break subintervals at the points where concentrations were measured and linearly interpolate between the EMCs measured at each end of the subinterval to select an estimator for the subinterval. Base documentation of meeting the code modification/alteration approval conditions on the following loading reductions: TSS and Pb--67% minimum in any water-year and 77% average over two successive water-years; Cu and Zn--48% minimum and 58% average; TP--32% minimum and average. Also base documentation of meeting the code modification/alteration approval conditions on oil and grease concentration in effluent grab samples never exceeding 15 mg/L. To evaluate such actions as aeration, water recirculation, and water makeup, estimate loading reductions during periods when these actions take place and compare with other periods. Note trends associating system operation with performance, and identify operating actions that improve performance. After confirming with additional monitoring, use this information to set the most beneficial operating practices. 21 REFERENCES American Public Health Association. 1989 . Standard Methods for the Examination of Water and Wastewater, 17th ed. American Public Health Association, Washington, D. C. Horner, R. R. 1988 . Biofiltration Systems for Storm Runoff Water Quality Control. Municipality of Metropolitan Seattle, Seattle. Reinelt, L. E. and A. Grimvall. In press. Estimation of nonpoint source loadings with data obtained from limited sampling programs. Environmental Monitoring and Assessment. Tetra Tech, Inc. , University of Washington, and Battelle Pacific Northwest Laboratories. 1988 . Recommended Protocols for Measuring Conventional Water Quality Variables and Metals in Fresh Waters of the Puget Sound Region. Puget Sound Estuary Program, U. S. Environmental Protection Agency, Region 10, Seattle. Welch, E. B. 1992 . Manual for Lake Quality Assessment and Control, Longacres Lake. Report to L. C. Lee Associates, Inc. , Seattle. U. S. Environmental Protection Agency. 1983 . Methods for Chemical Analysis of Water and Wastes. Environmental Monitoring and Assessment Laboratory, Cincinnati. U. S. Environmental Protection Agency. 1986 . Of ice of Solid Waste Manual SW-846. Office of Solid Waste, Washington, D. C. U. S. Environmental Protection Agency. 1991. Guidance Manual for the Preparation of NPDES Permit Applications for Storm Water Discharges Associated with Industrial Activity. Office Of Water, Washington, D. C. 22 Larry E.Allen Permits Administrator West Region Facilities Asset Management B"AFZW" Boeing Commercial Airplane Group P.O.Box 3707,#MS 19-35 Seattle,WA 98124-2207 Telephone 206-544-1644 Fax 206-655-5043 Pager206-994-6181 Cellular 206-949-2565 t April 28, 1996 R-1150-96-DST-177 To: Larry Allen 19-35 cc: Paul Read 19-39 Charlie Keller 19-16 Lori Pitzer 2R-71 Bart Heath 2R-71 Subject: Customer Service Training Center Stormwater Monitoring Requirements for the City of Renton Ordinance 4342 Attached, please find the water quality monitoring data as requested by Ron Straka during our meeting on November 1, 1995. It is our understanding that unless evaluation of the submitted data requires otherwise no further monitoring will be pursued. If you have any questions or require any additional information please feel free to contact me a 965-2703. Doris Turner Water Quality R-1150, MS 63-41 dst c:uongacres\si tedata.doc 04/28/96 Customer Service Training Center City of Renton Monitoring Analyte: Copper Lead Zinc FOG BTEX pH TSS TP TKN (PPm) m m m b m L m -P/L mg-NIL Date: 11/29/95 Site 1 0.02 <0.01 0.02 26.0 < 0.2 8.6 11.3 0.081 1.1 Site 2 0.03 0.02 0.08 3.00 < 0.2 8.6 35.8 0.10 ND Site 3 0.02 < 0.01 0.01 <2 < 0.2 7.5 5.60 0.10 0.39 12/19/95 Site 1 0.02 < 0.01 0.03 <2 <0.2 6.9 6.80 0.046 0.8 Site 2 0.01 <0.01 0.02 <2 <0.2 7.8 4.80 0.077 0.4 Site 3 0.02 < 0.01 0.02 3.6 < 0.2 7.4 6.80 0.1 1.7 1/30/96 Site 1 0.03 0.01 0.1 <2 0.27 6.9 13.2 0.085 1.3 Site 2 0.02 0.01 0.04 4.8 0.39 7.2 39.2 0.069 1.1 Site 3 0.03 < 0.01 0.04 <2 8.55 7.2 5.6 0.10 1.0 2/19/96 Site 1 0.02 <0.01 0.05 <2 < 0.2 6.7 7.60 0.048 0.5 Site 2 0.03 < 0.01 0.06 <2 < 0.2 7.0 19.2 0.076 0.5 Site 3 0.03 < 0.01 0.04 2.30 0.94 7.1 8.80 0.17 0.7 3/13/96 Site 1 0.03 < 0.01 0.03 <2 0.43 7.3 9.4 0.055 0.6 Site 2 0.04 < 0.01 0.01 <2 0.44 7.3 3.5 0.073 0.5 Site 3 0.02 < 0.01 0.01 <2 0.36 7.6 6.4 0.13 0.8 4/08/96 Site 1 0.02 < 0.01 0.02 3.40 < 0.2 6.8 17.4 0.09 0.8 Site 2 0.02 <0.01 0.02 2.00 < 0.2 6.9 9.2 0.12 1.1 Site 3 0.01 < 0.01 0.06 2.60 <0.2 7.6 5.4 0.33 1 2.1 Comments: 1. This sampling was done during an excessively wet period. At the particular time of sampling it was not raining. There was very little flow at Site 2 which is probably what accounted for the higher level of TSS. dst c:\Iongacres\sitedam.doc 04/28/96 Customer Service Training Center City of Renton Monitoring Analyte: Copper Lead Zinc FOG BTEX pH TSS TP TKN Date: (Ppm) m m) m b m m -P/L ma-N/L 11/29/95 Site 1 0.02 <0.01 0.02 26.0 <0.2 8.6 11.3 0.081 1.1 Site 2 0.03 0.02 0.08 3.00 <0.2 8.6 35.8 0.10 ND Site 3 0.02 <0.01 0.01 <2 < 0.2 7.5 5.60 0.10 0.39 12/19/95 Site 1 0.02 <0.01 0.03 < 2 < 0.2 6.9 6.80 0.046 0.8 Site 2 0.01 <0.01 0.02 <2 <0.2 7.8 4.80 0.077 0.4 Site 3 0.02 < 0.01 0.02 3.6 <0.2 7.4 6.80 0.1 1.7 1130/96 Site 1 0.03 0.01 0.1 <2 0.27 6.9 13.2 0.085 1 1.3 Site 2 0.02 0.01 0.04 4.8 0.39 7.2 39.2 0.069 1 1.1 Site 3 0.03 < 0.01 0.04 <2 8.55 7.2 5.6 0.10 1.0 2/19/96 Site 1 0.02 < 0.01 0.05 <2 <0.2 6.7 7.60 0.048 0.5 Site 2 0.03 < 0.01 0.06 <2 < 0.2 7.0 19.2 0.076 0.5 Site 3 0.03 < 0.01 0.04 2.30 0.94 7.1 8.80 0.17 0.7 3/13/96 Site 1 0.03 < 0.01 0.03 <2 0.43 7.3 9.4 0.055 0.6 Site 2 0.04 < 0.01 0.01 <2 0.44 7.3 3.5 0.073 0.5 Site 3 0.02 < 0.01 0.01 <2 0.36 7.6 6.4 0.13 0.8 4/08/96 Site 1 0.02 < 0.01 0.02 3.40 <0.2 6.8 17.4 0.09 0.8 Site 2 0.02 < 0.01 0.02 2.00 <0.2 6.9 9.2 1 0.12 1.1 Site 3 , 0.01 1 < 0.01 0.06 2.60 < 0,2 7.6 5.4 0.33 2.1 Comments: 1. This sampling was done during an excessively wet period. At the particular time of sampling it was not raining. There was very little flow at Site 2 which is probably what accounted for the higher level of TSS. dst c:uongacreslsitedata.doc 04/28/96 May 14, 1996 R-1150-96-DST-207 To: Lori Pitzer 2R-71 cc: Bart Heath 2R-71 Mike Babich 63-41 Paul Read 19-39 Charles Keller 19-16 Larry Allen 19-35 Subject: CSTC (Customer Service Training Center) Wetlands Mitigation Monitoring Sampling On April 24, 1996 samples from the Springbrook Creek and the CSTC outfall to Springbrook Creek were obtained as part of the Wetlands Mitigation Monitoring program. The water was sampled in the morning during a rainy period and as such is being classified as wet flow conditions. The tideflex valve at the outfall was continuously discharging water to the Creek and was approximately 1/3 the way up the valve. No unusual conditions existed while sampling and visually all of the samples were clear. Attached are the results of the analysis performed on these samples. If you have any questions or require any additional information please contact me at 965- 2703. Doris Turner Environmental Engineer Water Quality; Renton SHEA M/S 63-41 c:uongacre4inm4-96.doc CSTC Wetlands Mitigation Monitoring Data Wet Flow Conditions Monitoring Main Outfall to Springbrook Creek at Units Creek 16St bridge Lab Id:96-A344 Lab Id: 96-A345 ARI ID: N762A ARI ID: N761A H 7.7 7.1 Dissolved oxygen 8.8 8.9 m Electrical conductivity 215.0 85.0 mmho/cm Organic Halogens TTO's < 5 < 5 ppb Fats,oil & grease < 2 < 2 m Organic Carbon 8.9 7.6 m Total Suspended solids see below * see below * m Settleable solids < 0.5 < 0.5 m /hr Biochemical oxygen demand 7 6 mg/L OD Chemical Oxygen Demand 27 24 mg/L COD Nitrate 0.047 0.47 m -N/L Nitrite < 0.01 < 0.01 mg- Total Phosphorous 0.12 0.13 m -P/L ND - undetected at detection limit ppb - part per billion * - settleable solids was run instead of total suspended solids in error c:\lo ngacre\wmm4-96.doc i Boeing Commercial Airplane Group P.O. Box 3707 Seattle,WA 98124-2207 November 14, 1995 6-8W5H-LA-5284 NOV 16 1995 Ron Straka Supervisor Surface Water Utility, City of Renton CITY e`r �D rON 200 Mill Avenue South Engineering Dept. BOE/NG Renton, WA 98055 Dear Ron: I hope this letter will reflect our conversation of 11-1-95 regarding water quality monitoring and assessment plan for the Boeing Customer Service Training Center. I apologize again for the delay in implementing the original monitoring plan. I would like to propose, with your approval a monitoring plan which I hope will meet the requirements of Ordinance 4342. The Boeing Company will take grab samples at 3 locations (per attached) once a month starting November of 1995 through April of 1996. This data will be submitted to the City of Renton by July 1st 1996 for your evaluation. This data should confirm that this design meets or exceeds code requirements. When the City of Renton has had sufficient time to assess the technical data, Boeing would request a written response as to meeting the requirements of Ordinance 4342. If you have any questions, please call (206) 544 - 1644. Thank you, � " Larry E. Allen t Y Y \ \ 1 \\ I \,Vj I any er site fL- �-- , 25-01 25-02 .01 Sampler , R site #3 Gee 0`�` 0 N DT-MAP (ENV) CSTC SITE DEVELOPMENT SITE PLAN STORM WATER TREATMENT AND AQUATIC FEATURES CITY OF RENTON MEMORANDUM DATE: May 20, 1992 TO: Gregg Zimmerman Tom Kriss Lenora Blauman FROM: Ron Straka A0 SUBJECT: The Boeing Company's Customer Service Training Center Project Code Modification/Alteration Request The Surface Water Utility has reviewed the Boeing Company's code modification/alteration request for the Customer Service Training Center (CSTC)project as allowed under Ordinance No.4342. The Boeing Company has requested code modification/alteration to the City of Renton Storm and Surface Water Drainage chapter 4-22. The code modification/alteration request (see attached documents) pertains to the portions of the City adopted 1990 King County Surface Water Design Manual (KCSWDM) Core requirement No 3 (biofiltration requirement) and Special Requirement No. 6 (coalescing plate oil/water separators)surface water management standards. The Surface Water Utility approves of the requested code modification/alteration request based upon the information provided by the Boeing Company (see attachments). This information includes a technical letter from Dr. Richard R. Horner who teaches at the University of Washington's Environmental Engineering and Science Department. Dr. Horner a nationally respected expert in the field of water quality and resource engineering. Dr Horner reviewed the code requirements for the Boeing CSTC project and estimated the pollutant removal that would be obtained. He then reviewed the proposed storm and surface water management facilities design for the Boeing CSTC and estimated the percentage of pollutant removal that would be achieved by the Boeing system. This comparison shows that the proposed Boeing CSTC storm and surface water management plan will remove more pollutants than the code requirements would for the selected parameters. The Surface Water Utility approves the code modification/alteration request based upon this evidence and accepts the conceptual drainage plan for the Boeing CSTC project. The request demonstrates that the proposed design meets the intent of the code, will accomplish equivalent pollutant removal as required by code(actually exceeds code requirements), it will equally protect the environment and satisfies the other requirements of Ordinance No 4342 as discussed in the formal request. As allowed by Ordinance No 4342, the following conditions of this approved code modification/alteration request must be complied with by the Boeing Company as specified in the conditions. The conditions of the code modification/alteration request are as follows: 1.) The applicant (The Boeing Company) shall develop a Water Quality Monitoring and Assessment Plan to be approved by the City of Renton Surface Water Utility. The Utility recommends that the Boeing Company receive direction from Dr. Horner in the development of the Water Quality Monitoring and Assessment Plan. This condition must be complied with prior to the issuance of the CSTC projects construction/building permit. 2.) The applicant shall implement the approved monitoring plan with continuous monitoring for a period of time as specified in the approved plan based upon Dr.Horner's recommendations. The water quality monitoring shall start following the completion of construction at the time of the projects Final Occupancy Permit issuance (CSTC building). 3.) Upon completion of the approved water quality monitoring period, the applicant shall provide within two months the City of Renton with technical report which documents the results of the water quality monitoring and assess the effectiveness of the proposed systems pollutant removal rate for comparison with code pollutant removal rates. If the proposed CSTC storm and surface water systems pollutant removal rates are less than what the code requirement pollutant removal '• rates are, then the Boeing Company shall install the required coalescing plate oil/water separators, or propose alternate measures which may be subject to additional conditions by the City of Renton Surface Water Utility. 4.) The applicant (Boeing)shall provide the City of Renton with a bond that is valid for the duration of the approved water quality monitoring duration period plus six months,which is equal to 100% of the cost to design/construct/install the projects required coalescing plate oil/water separators. These conditions are justified in order that the proposed CSTC storm and surface water management system works as certified by the applicants engineer and to ensure protection of the public's safety and health as well as the environment. If you have any questions regarding this subject,please contact me at(206)277-5547. Boeing Commercial Airplane Group P.O.Box 3707 Seattle,WA 98124-2207 May 11, 1992 Ms. Lenora Blauman City of Renton ,DOE/N� 200 Mill Avenue South Renton, WA 98055 Re: Boeing Customer Services Training Center ("CSTC") / Administrative "Variances" Required for Storm and Surface Water Drainage System Dear Lenora: As you know, City of Renton Ordinance No. 4342 ("Ordinance") amends the Stormwater Drainage Section of the City's Building Regulations to provide that any material or method of construction may be used to construct storm and surface water drainage facilities, so long as that material or method has been approved by the Planning/Building/Public Works Department Administrator. The Administrator's approval must be based on a finding that the material or method of construction proposed is "at least the equivalent of that prescribed in [the Renton Municipal Code) in suitability, strength, effectiveness, durability, safety, maintainability and environment protection, " which finding must be supported by evidence provided by the applicant. In general, the storm and surface water drainage facilities planned for the CSTC conform to the Core and Special Requirements of the King County Surface Water Design Manual ("Manual") . However, Boeing proposes to utilize alternative methods of construction with respect to Core Requirement No. 3 (regarding run-off control) and Special Requirement No. 6 (regarding coalescing plate oil/water separators) . I. SYSTEM REQUIRED BY MANUAL; CORRESPONDING PERFORMANCE STANDARDS Core Requirement No. 3 requires the use of biofiltration swales for projects that (a) include more than 5, 000. square feet of impervious surface and (b) are [03008-0352/SB921290.DOCJ Ms. Lenora Blauman May 11, 1992 Page 2 subject to vehicular use. Special Requirement No. 6 states, in part, that if a proposed project will include more than five acres of impervious surface that will be subject to more than 2,500 vehicle trips per day, a coalescing plate oil/water separator is required. BOE/NG Thus, the system required by the Manual requires a conveyance system (a series of pipes and catch basins) to collect flow from roadways and parking lots. After collection, the flow would pass through an oil/water separator (using coalescing plate technology) , then into a system of biofiltration swales, and finally into a three- stage wet pond system. Dr. Richard R. Horner has reviewed the system described above and estimates that it will achieve the following removal rates: TSS=Total Suspended Solids TP=Total Phosphates MATERIAL REMOVAL RATE TSS and Pb 67-87% Cu and Zn 48-68% TP 32% ~ II. ALTERNATE SYSTEM PROPOSED FOR THE CSTC; CORRESPONDING PERFORMANCE STANDARDS The storm and surface water drainage system designed for the CSTC includes a conveyance system that incorporates twice the normal number of catch basins - a greater number of catch basins creates more sediment trap area. All catch basins are located off-line to prevent stirring of sediments collected in the catch basins during storms. In addition, each catch basin is provided with an elbow to trap floatables and to act, in part, as a gravity oil/water separator. The conveyance system transports the flow to a first stage wet vault (grit chamber) that provides some additional gravity oil/water separation, then into second and third stage ponds (which contain much greater surface area and volume than required by Code) and [03008-0352/SB921290.Doq 5/11/92 Ms. Lenora Blauman May 11, 1992 Page 3 then through a wet biofiltration swale-stream system to the outfall at Springbrook Creek. Dr. Horner has reviewed this system and, discounting the benefits of the catch basins and the grit chamber, reports the following expected removal rates: DOE/.NG MATERIAL REMOVAL, RATE TSS 99% Pb 95-96% Cu and Zn 65-73% TP 61% These removal rates are significantly higher than those provided by the system required by Code. In particular, TSS removal is at. least 12% greater than that provided by the Code system; Pb removal is at least 8% greater; Cu and Zn removal is at least 5% greater; and TP removal is 29% greater. In addition, the proposed system meets the Ordinance'S objectives of safety, function, appearance, environmental protection and maintainability as follows: A. Safety. All culverts over 24 inches in diameter are designed with protective cages in place around entrances and exits to prevent entry by children. This measure exceeds Code requirements. The existing sill to the site utilizes bioengineering slope-stability techniques to enhance safety and limit the possibility of failure. All other Code requirements for safety are met. B. Function. Comparable function is demonstrated by the removal rates described above and the reduction of outflow rates . by over 50% for all storms, not only two- and ten-year events as required by Code. C. Appearance. The stormwater system is viewed as a ' landscaping amenity; consequently, its appearance is better than required by Code. (03008-0352/SB921290.DOC] 5/11/92 Ms. Lenora Blauman May 11, 1992 Page 4 D. Environmental Protection. The removal-rate comparison set forth above indicates that the proposed system exceeds the standard of environmental protection required by Code. E. Maintainability. Because this project is ,ff®E/NG located on private property and the storm drainage system is viewed as a landscaping amenity, Boeing will retain maintenance responsibility. Thus, there will be no maintenance costs of the system to the City. F. Effect on Neighboring Properties. Downstream properties will be benefitted by the reduced outflow rates from the site for all storm events; the project will not be injurious to other properties. For your information and review, I attach relevant sections of the Manual; a comparison of existing versus post-development runoff conditions excerpted from the TIR prepared for the CSTC; and a copy of a letter from Dr. Horner to Dave Benson of Sverdrup outlining the results of Horner's system comparison. Please do not hesitate to contact me if you have questions regarding our requested administrative variances. t yo rs,3 rt Program Manager Org 6-4067, MS 6Y-50 Phone (206) 393-7101 Enclosure cc: R. E. McCaan ' Perkins Coie R. H. Wicklein [03008-0352/SB921290.DOC] 5/11/92 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL 1.2.3 CORE REQUIREMENT #3: RUNOFF CONTROL r Proposed must projects provide runoff control through a combination of peak rate runoff control facilities and on-site biofiltration measures as described below. Peak Rate Runoff Control Proposed projects must provide peak rate runoff control to limit the developed conditions peak rates of runoff from specific design storm events not to exceed the pre-development peak rates for the proposed project site "existing conditions" as described below. Three basic methods for peak rate runoff control are possible: detention, retention, and infiltration. Detention Is the collection and temporary storage of surface water (typically over several hours) with the outflow rate restricted—usually to the pre-developed outflow rate. Retention is the collecting and holding of surface and stormwater with effectively no surface outflow (outflow occurs by evapotranspiration). Infiltration is the soaking of surface water into the ground (typically for several hours or days). Infiltration not only reduces or eliminates surface runoff, but also helps to maintain the hydrologic balance of the surface water system. Infiltration can limit erosion and recharge groundwaters that supply water to wetlands, streams, and wells. Preserving infiltration after development is by far the most effective mechanism in preventing adverse Impacts to the surface water system. Because of these benefits, King County encourages the use of Infiltration systems for runoff control where the appropriate soil conditions exist. Proposed project peak rate runoff control must be located on-site. An exemption from on-site peak rate runoff control may be granted for the special conditions specified at the end of this core requirement section. Biofiltration Proposed project runoff resulting from more than five thousand square feet of impervious surface, and subject to vehicular use or storage of chemicals, shall be treated prior to discharge from the project site by on-site biofiltration measures as described in Section 4.6.3 in Chapter 4. The biofiltration design flow rate shall be the peak rate of runoff for the 2-year 24-hour duration design storm event. Note, biofiltration facilities installed following peak rate runoff control facilities may be sized to treat the allowable release rate (pre-developed) for the 2-year 24-hour duration design storm event for the peak rate runoff control facility. Blofiltration facilities installed prior to peak rate runoff control facilities shall be sized based on the developed conditions. Proposed Project Site 'Existing Conditions" In performing the analysis for the design of runoff control, it Is essential to first determine the proposed project site 'existing conditions' from which the pre-development runoff rates can be computed for specific design storms. Existing conditions are not always synonymous with those of the natural, totally undeveloped site. In some instances substantial modifications (such as diversions, piping, clearing, and grading) have already increased and altered surface water runoff leaving the site, but no permit, nor accompanying engineering plan, was ever approved. In other instances, an approved drainage system exists and the existing system must be analyzed for its performance. There are two definitions for proposed project site "existing conditions" depending on the site. Sites with Existing Approved Drainage Systems: The proposed project site "existing conditions' are defined as those that occur with the existing drainage facilities constructed per approved permits and engineering plans. The current performance of existing drainage and detention facilities shall be determined by using the analysis methods described In Section 3.5 in Chapter 3. Sites with No Existing Approved Drainage Systems: The "existing conditions' are defined as those that existed prior to May 1979, which is the date of publication of "Requirements and Guidelines for Storm Drainage Control in King County" by the King County Public Works Department's Hydraulics Division, the 1.23-1 1/90 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL Peak Rate Runoff Control Performance Curve A "peak rate runoff control performance curve' plots the allowable peak runoff rates for a range of design storm frequencies, as illustrated In Figure 1.2.3A the "Standard Peak Rate Runoff Control Performance Curve`. In the absence of other Special Requirements which dictate a more thorough analysis, the BALD Division evaluates peak rate runoff control only for the 2-, 10-, and 100-year frequency storm events represented on this curve. Peak rate runoff control facilities must be designed to produce post- development peak runoff rates at or below this curve for the 2-and 10-year, 24-hour duration design storm events. More restrictive runoff control performance curves may be required under conditions specified In the 'Special Requirements" section of this chapter. The post developed runoff for the 100-year, 24-hour duration design storm event shall be routed through the conveyance system and the peak rate runoff control facilities to evaluate any significant adverse impacts downstream (see Sections 1.2.2 and 1.2.4). Additional control to reduce the post-developed peak runoff for the 100-year, 24-hour duration design storm event is one mechanism that may be used to mitigate significant adverse impacts downstream. The required performance above the 10-year, 24- hour duration design storm up to the 100-year, 24-hour duration design storm event, therefore, is dependent upon downstream conditions and how much attenuation the peak rate runoff control facility designed for 2- and 10-year, 24-hour duration design storm events provides for the 100 year, 24-hour duration design storm event. FIGURE 1.2.3A STANDARD PEAK RATE RUNOFF CONTROL PERFORMANCE CURVE For the 100-year,24-hour design storm event,the peak rate runoff -° control facility release rate depends on _ the significance of downstream impacts. ._... '. LU , Pre-development peak rates LL° (allowable release rates) tl. ' O z , Y ' U Ul v Post-development "s a Q2 ' peak rate runoff control facility release rates 2 10 100 24 HOUR DESIGN STORM FREQUENCY(YEARS) 1.2.3-2 1/90 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL Detention Facilities There are two main types of detention facilities: ponds; and, tanks or vaults. The methods of analysis and design standards for detention facilities can be found in Section 4.4 in Chapter 4. Factor of Safetv: The design volume of detention facilities used to meet the standard peak rate runoff control performance curve for the 2-and 10-year, 24-hour duration design storm events shall be increased by a 30 percent factor of safety. This requirement shall be met by increasing proportionally by 30 percent the design detention volume between each 1 foot of storage depth without increasing the total depth of storage or altering the design control orifice/weir sizing. Detention Ponds: Detention ponds are the most desirable alternative for detention facilities for water quality benefits, relative ease of Inspection and access for maintenance. King County encourages the design of multi-purpose detention ponds which can serve the multiple purposes of recreation (such as playgrounds or picnic areas), wildlife habitat (wetlands areas) and aesthetics Qandscaping to provide for a natural appearance). Multi-purpose ponds must meet all the requirements of the purposes they are required to perform. In multi-purpose ponds incorporating recreational facilities, the recreational facilities must be designed in a manner compatible with the storm water functions and maintenance standards. Detention ponds may combine the performance requirements of wetponds (see Special Requirement #5 and Section 4.6.2 in Chapter 4). Detention Tanks and Vaults: Detention tanks and vaults are underground facilities for the storage of surface water. Tanks are typically constructed from corrugated pipe and vaults are constructed from reinforced concrete. Tanks and vaults provide less water quality benefit (biofiltration and biologic activity) than ponds, therefore, biofiltration measures are especially important. Private Parking Lot Pondina: Private parking lots may be used to provide additional peak rate runoff control detention volume for the post-developed peak rates of runoff for design storms greater than the 10-year, 24-hour duration design storm provided that: (1) the depth of water detained can not exceed 1.0 feet at any location in the parking lot; and (2) the minimum gradient of the parking lot area subject to ponding shall be 1 percent; and (3) the emergency overflow path meets the same requirements as for infiltration systems. Roof Pondina: Ponding of roofs of structures will be allowed to be used for peak rate runoff control detention volume provided that: (1) the depth of water ponded can not exceed 1.0 feet at any location on the roof; and (2) the minimum pitch of the roof area subject to ponding shall be 1/4 Inch to 1 foot; and (3) the roof support structure is analyzed by a structural engineer to address the weight of the ponded water, and (4) the roof area subject to ponding is water-proofed with a method with a minimum expected service life of 30 years. Retention Facilities There are two basic types of retention facilities: ponds and closed depressions. Retention ponds are constructed by a combination of excavation and/or berming. Closed depressions may be established as retention facilities, and in some cases enlarged to accommodate additional surface and stormwater runoff by excavation and/or berming. 123-3 1/g0 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL Usually retention facilities will not be a cost effective means for providing peak rate runoff control, but rather are employed to control the Increased volume of runoff from a proposed projects as is required by Special Requirement #7: Closed Depressions in Section 1.3.7 of this Chapter. The pre- and post-development peak runoff rates for the 100-year, 7-day duration design storm events are evaluated, along with the standard peak rate runoff control performance curve, when retention facilities are employed in order to control increased volume of runoff from proposed projects. In these cases, retention facilities shall be analyzed and sized using the methods described in Section 3.6 in Chapter 3, and designed using the design standards contained in Section 4.4 in Chapter 4. Note, in some cases, retention facilities will have significant infiltration capability and, in these cases, must also meet the design standards contained in Section 4.5 in Chapter 4. Infiltration Facilities Infiltration facilities, as with detention systems, must be sized to meet the required peak rate runoff control performance curve. More restrictive runoff control curves may be required under conditions specified in the 'Special Requirements' Section 1.3 of this chapter. Note, the factors of safety for Infiltration systems are incorporated within the methods of analysis and design standards described in Section 4.5 In Chapter 4. For the design requirements and standards for infiltration facilities see Section 4.5 in Chapter 4. There are many practical limitations on infiltration facilities, due to the very slow permeability rates of some soils and the need to prevent contamination of groundwater resources. Because of these practical limitations, King County allows infiltration facilities only in the following Soil Conservation Service series soils: Arents ("An' only), Everett, Indianola, ldaus, Neilton, Pilchuck, Puyallup and Ragnar. A soils report is required for all proposed infiltration facilities to verify the mapped soils series or to classify the series of the soil (if previously unmapped). Soils logs are prepared to provide the data for the report and to investigate and confirm that the seasonal high groundwater is at least 1 foot below the bottom of a_ proposed infiltration system. Where doubt exists as to the depth of seasonal high groundwater an investigation must be conducted during the winter months prior to permit approval. Infiltration facilities may not be operated until LII proposed project improvements which produce surface runoff are complete, especially revegetation and landscaping. In the case of projects with individual lots remaining undeveloped, these lots must contain and infiltrate their runoff through individual sediment traps (see Section 5.4.4.1 in Chapter 5) acting as infiltration ponds as until permanent improvements and landscaping are established. Infiltration facilities must be designed based on infiltration testing and a soils report prepared by a professional civil engineer with expertise in soil engineering. An emergency overflow path must be identified for infiltration facilities and noted on the engineering plan. This overflow path must be analyzed to meet the requirements of Core Requirements #1 (see Section 1.2.1) and #2 (see Section 1.2.2) for the 100-year, 24-hour duration design storm, except Downspout Infiltration Systems (see Section 4.5.1 in Chapter 4). Infiltration facilities may be especially useful In the following circumstances, provided the proper soil conditions are present and all requirements can be met. (1) The proposed project discharges to a closed depression. (2) The proposed project discharges to a severely undersized conveyance system that restricts the runoff volume that can be accommodated. (3) The proposed project is in a Critical Drainage Area requiring runoff volume control. 1.2.3-4 1/90 :KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL Exemptions From On-Site Peak Rate Runoff Control On-site peak rate runoff control will not be required for a proposed project in the following situations. (1) Nealigible Peak Runoff Rate Increase*: o The proposed project site post-developed peak runoff rate for the 100-year, 24-hour duration design storm event is calculated to be less than 0.5 cis more than the pre- developed peak runoff rate for the proposed project site existing runoff conditions. OR o The project proposes to construct 5,000 square feet, or less, of new impervious surface, *Proposed projects in designated critical drainage areas requiring stricter peak runoff rate or runoff volume controls shall not qualify for this exemption. OR (2) Direct Discharge:** The proposed project will discharge surface and stormwater runoff without on-site peak rate runoff control directly to: A Regional Facility. Direct discharge of surface and stormwater runoff to a regional facility will be allowed if: the facility has been demonstrated to adequately to control the proposed project's increased peak rate of runoff by an adopted fling County basin plan or by a detailed drainage analysis approved by the SWM Division; the facility will be available by the time of construction of the project; AND, the conveyance system between the proposed project and the regional facility will be adequate for the proposed project's design peak runoff with no significant adverse impacts. A Receiving Water. Direct discharge of surface and stormwater runoff to the following receiving waters may be allowed. Proposed projects that require Master Drainage Plans (see Special Requirement #3) shall demonstrate no significant adverse impacts from direct discharge to a river. Cedar River Green/Duwamish River (below river mile 6.0, F.E.M.A.) Puget Sound Lake Sammamish Sammamish River Skykomfsh River Snoqualmie River Lake Washington White/Stuck River A Lake, Wetland or Closed Depression. See Special Requirement #8: Use of Ickes, Wetlands or Closed Depressions for Peak Rate Runoff Quantity Control, in Section 1.3.8. The applicant should note that many lakes, wetlands or closed depressions will not qualify for this exemption. **Projects qualifying for Direct Discharge must meet the requirements of Special Requirement #5: Special Water Quality Controls in Section 1.3.5. 1.2.3-5 1/90 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL Bypasses Proposed project runoff may bypass the proposed project peak rate runoff control facilities provided that: (1) the proposed project peak rate runoff control facilities are designed to compensate for the controlled project area by limiting the total developed peak runoff rate (both controlled and uncontrolled) to the pre-development peak runoff rates for the proposed project site at the point of discharge, AND (2) both the bypass area and the peak rate runoff control facility discharge to the same subbasin, AND (3) the discharge from the bypass will have no significant adverse impacts on downstream properties. Upstream off-site runoff must bypass the proposed project on-site peak rate runoff control facilities in a separate conveyance system, unless the existing peak runoff rate from the upstream off-site area for the 100-year, 24-hour design storm event is: less than 50 percent of the proposed project site developed conditions peak runoff rate for the 100-year, 24-hour duration design storm event. Tracts The runoff control facilities to be maintained and operated by the King County Department of Public Works (see Section 1.2.6) must be located in a tract or right-of-way created by a legal subdivision and dedicated to King County. Access roads serving these facilities must be also be located in the tract or right-of-way and must be connected to an improved King County road right-of-way, ,y 1.2.3-6 1/90 SD TABL2.XLS a Comparison of Existing Versus Post-Development Conditions Storm Pre Dev Post Dev" Change Volume pre pav post Dev pre Dev Closed Post peV Cloaea Closed Depres loi Event Outflow Qutflow Post/Pra Increase MaxIeVatlon; f�aX'Elevaton : pepresslon bepresslan pkfferehtl�l NGVD) (NGVD) .. :,:... NGVp). (NGVp) Water Quality 2.60 1.60 62% 19,376 9.06 8.65 11.15 8.91 -2.24 2-Year 24-Hour 22.49 11.55 51% 36,319 10.59 9.15 12.80 10.29 -2.51 5-Year24-Hour 27.36 14.72 54% 39,168 10.88 9.33 13.19 10.70 -2.49 10-Year 24-Hour 31.41 16.04 51% 39,547 11.12 9.64 13.61 11.17 -2.44 25-Year 24-Hour 35.05 18.84 54% 38,645 11.34 9.94 14.05 11.62 -2.43 50-Year 24-Hour 35.41 19.23 54 42,403 11.36 9.97 14.08 11.67 -2.41 100-Year 24-Hour 37.26 22.36 60% 52,575 11.54 10.22 14.43 12.08 -2.35 100-Year 7-Day 36.21 21.26 59% 93,313 11.42 10.13 15.24 (1) 15.20 (2) -0.04 Notes: 1. Outflow of 9.98 cfs occurs above elevation 15.00 over the existing NE Meadow Sill. 2. Outflow of 42.88 cfs can occur above elevation 15.00 over the proposed Floodplain Sill. Sverdrup Corporation Fire im , Ir, ,n. Richard R. Horner, Ph.D. Environmental Engineering and Science 230 N.W. 55th Street Seattle. Washington 98107 (206) 782-7401 February 29, 1992 Mr. J. David Benson Sverdrup Corporation 3300 Carillon Point P. O. Box 97062 Kirkland, WA 98083-9762 Dear Dave: This letter provides ,my evaluation of a portion of the stormwater management system proposed for the Boeing Longacres site. I have performed the evaluation as requested by Randall Parsons of the City of Renton; i. e. , by comparing the estimated water quality improvement performance of the proposed system and the system required by the Renton code. This letter covers my analysis and findings for Catchment C (including the occasional drainage from Catchment A that will enter the Catchment C system) . I will provide similar evaluations after you finish your proposed designs for the Catchment B and SW 16th systems. METHODS I estimated the stormwater treatment performance of wet ponds using the methods developed by Driscoll (1983) from data collected on numerous such systems during the U. S. Environmental Protection Agency's Nationwide Urban Runoff Program (NURP) . These methods relate long-term effectiveness (the average over numerous runoff events) to the "volume ratio" (pond dead storage volume to mean storm runoff volume) . The latter term is calculated from mean precipitation quantity, a regional climatological statistic. This ratio has been found to govern the capture of pollutants during the quiescent period between runoff events. The NURP methods also recommend pond surface area in relation to contributing catchment area (the "area ratio") and overflow rate for good performance. The larger the surface area is in relation to the watershed, the better is the operation of pollutant removal mechanisms relying on light and interaction with the atmosphere. Minimizing overflow rate improves short- term removals of the larger solids during and immediately after Mr. J. David Benson February 29 , 1992 Page 2 storms, when the live storage zone of the pond is filled. The recommended maximum overflow rate is 10 cm/hour. I combined the volumes and surface areas provided by second- and third-stage ponds for the analysis. Initially, I took no account of wet vaults, because their overall water quality benefits are very limited as a result of short residence time and excluding light and atmospheric interactions. It should be noted, however, that vaults are useful to increase water storage for release rate control, as presettling chambers to catch the largest particles, as oil/water separators when fitted with appropriate baffling and skimming equipment, and as potential locations for advanced oil/water separators should they ever be needed. I regarded the outlet channel, which is to be at least partially vegetated, as a biofilter and evaluated its performance by using results from the Washington State Highway Runoff Water Quality project (Mar et al. 1982; Horner and Mar 1982; Horner 1988) . Approximations were required because of current uncertainty concerning the final configuration of the channel. I 'reasoned that it should be at least equivalent in performance to the designs recommended by the references cited and required by the Renton code based on the King County Surface Water Design--- Manual* (King County Surface Water Management Division 1990) . The basis for my reasoning is that the channel will have greater size, and therefore water residence time, than biofilters designed strictly according to the requirements, although some of the cross section may not be vegetated. I recommend that the design include native hydrophytic vegetation over the full width and length of the channel for the maximum water quality benefits. I analyzed performance in terms of the expected removal efficiencies for the following pollutants: total suspended solids (TSS) ; total phosphorus (TP) ; and the metals lead (Pb) , copper (Cu) , and zinc (Zn) . The NURP data suggest that removals of total Kjeldahl nitrogen (TKN) and chemical oxygen demand (COD) in a wet pond are similar to those of Cu and Zn, but no basis exists to evaluate trapping of those pollutants in a biofilter. TP removal by biofiltration is seasonally variable because of the annual cycling of vegetation through a growth period, when nutrient uptake occurs, and a death and decay phase, when stored nutrients are released. Although these losses through release could partially be avoided by a fall harvesting program, it is most prudent to consider biofiltration to provide no net TP capture over a full annual period for the current analysis. The applicable Renton code requirements and the proposed design for Catchment C involve a wet pond and biofilter in series. Data are available in the references cited earlier to estimate the performance of the two elements in the sequence separately. It is reasonable to assume that in a series arrangement, however, the second device in line will not perform Mr. J. David Benson February 29 , 1992 Page 3 at the same level as if it were alone, because the pollutants that are easiest to remove will have already been captured. The available research provides no basis to establish the loss in efficiency of the second element. To compare on the same basis a treatment system required by the code with the system proposed, the analysis assumed two "penalty" levels for the second device: 25 and 50 percent. Therefore, the overall efficiency of the series (Es, as a fraction) was estimated as: ES = 1 - (1 - El) (1 - xE2) ; where El = efficiency of element 1 (as a fraction) , E2 = efficiency of element 2 (as a fraction) , and x = the efficiency remaining after imposition of the "penalty" (0. 75 or 0. 50) . Efficiency as a percentage is 100 times the fractional efficiency. ANALYSIS OF CATCHMENT C Code Requirements From the water quality standpoint, the characteristics of Catchment C make it subject to Core Requirement #1 and Special Requirements #5 and #6 in the King County Surface Water Design Manual. Core Requirement #1 mandates peak runoff Sate control, plus biofiltration as a result of having > 5000 ft of impervious area subject to vehicle use. Special Requirement #5 specifies a wet pond for treatment based on > 1 acre of impervious area subject to vehicle use and discharge to a Type 1 or 2 stream within 1 mile. The requirement further stipulates that the pond surface area be no less than 1 percent of the contributing impervious area and have a volume that is. at least equal to the mean annual runoff volume (i. e. , the volume ratio should'-be at least 1) . Special Requirement 96 mandates a coalescing plate oil/water separator because of the anticipated > 2500 vehicle trips per day. Therefore, the code requires a biofilter and a wet pond (in either order) and a coalescing plate oil/water separator. I based the estimated treatment efficiencies for the wet pond according to the minimum code requirement (a volume ratio of 1) . The efficiencies differ somewhat depending on which element is assumed to be first and the efficiency penalty assumed for the second element. I calculated them for both sequences and for penalty assumptions of 25 and 50 percent and estimate them to be in the following ranges:. TSS and Pb--67 - 87% TP--32% Cu and Zn--48 - 680 Coalescing plate oil/water separators are meant for industrial applications where influent oil concentrations are consistently larger than generally found in urban runoff. They Mr. J. David Benson February 29 , 1992 Page 4 are capable of reducing oil and grease concentration to 15 mg/L (Horner and Wonacott 1985) . General urban and even highway runoff usually contains lower concentrations than this performance limit. A small amount of data (Horner 1988) indicate that biofilters can reduce the usual runoff concentrations to a much lower level (< 5 mg/L) . Therefore, a coalescing plate separator would serve mainly as a pretreatment device and a trap for accidental spills in a system also containing a biofilter. Proposed System The stormwater system proposed for Catchment C consists of four wet vaults, two second-stage ponds, a third-stage pond (the large lake) , and an outlet channel. The two stages of ponds will provide a very large capacity and long water residence time to treat entering stormwater. Based on the volume ratio represented by the second- and third-stage ponds (24.7) and the two assumptions for the efficiency penalty for the outlet biofiltration channel, I estimate that the following treatment efficiencies, substantially higher than expected for a system meeting minimum code requirements, can be attained if the system is installed as designed and maintained in the same condition during operation: TSS--99* TP--61% Pb--95 - 96% Cu and Zn--65 - 73% Additional comparisons with the system required by the code involve the area ratio and overflow rate. While the minimum requirement for pond surface area is 1 percent of the contributing impervious area, the proposed pond system will occupy an area equal to 21.2 percent of the Catchment C impervious area and 8 .8 percent of the total 76.36 acres ih the current project. Overflow rates for the proposed system will be only about one-tenth of those that would occur in a system designed according to minimum code requirements. Even within the period of maximum overflow during storms, the proposed system will have rates below the NURP recommendation most of the time. Only with storms greater than about the 2-year, 24-hour event will the short-term overflow rate exceed that recommendation. In contrast, the minimum system would have rates above that level during most storms. The analysis described is based on the runoff contributions expected from Catchment C itself. On occasion drainage will also enter the third-stage Catchment C pond from Catchment A. At a maximum rate of 18 cfs, this contribution will not even begin until an event sized somewhere between the 50- and 100-year, 24- hour level. With the very large capacity of the proposed system and the relative rarity of this extra flow, I do not consider it to detract significantly from the expected performance of the system. Mr. J. David Benson February 29, 1992 Page 5 Your design proposes eliminating the coalescing plate oil/water separators required by the code. I believe that there will be no loss of protection from oil pollution for the following reasons. The proposed system does include T-section separators in catch basins and baffling in wet vaults for oil separation. These devices will serve as protection against accidental spills and pretreatment ahead of the wet pond/biofilter system in much the same way as coalescing plate separators would. In either situation most of the oil captured from routine runoff would occur in the biofilter. While a coalescing plate separator is more effective than the proposed devices, its capabilities are rarely needed at this type of site. The huge capacity of the pond system will provide further buffering of the receiving water from the effects of oil releases. I will provide my assessments of Catchment B and SW 16th by letter as soon as I receive your proposed designs. I will also forward the list of references cited in both letters at that time. Meanwhile, do not hesitate to call if you need anything additional. Sincerely, Richard R. Horner Boeing Commercial Airplane Group P.O.Box 3707 Seattle,WA 98124-2207 NO C7 May 23, 1995 ���� GNA R-1150-EJN-95-300 ;�:��eP�. ,J QF a BOE/NG City of Renton 200 Mill Avenue South Renton, WA 98055 Attention: Storm Water Utility Subject: Renewal Notice of Intent (NOI) for the Baseline General Permit for Discharge of Stormwater Associated with Industrial Activities As required per the State of Washington Department of Ecology's Baseline General Permit to Discharge Stormwater Associated with Industrial Activity, we are submitting a copy of our renewal Notice of Intent (NOI) for our Boeing Renton Facility. If you have any questions, please contact Joyce Nelson at 965-1403. Sincerely, Aa—Q— L. M. Babich, III Environmental Affairs Manager R-1150 M/S 64-41 enclosures Boeing Commercial Airplane Group PO. Box 3707 Seattle.`NA 98124-2207 May '), 1995 R-1150-EJN-95-285 Mr. James D. Krull Permit Management Section Water Quality Program Washington State Department of Ecology P.O. Box 47696 Olympia, WA 98504-7696 .�oEs�c Subject: NOI Renewal for Baseline General Permit Number S03-000232 Reference: Telecon from J. Nelson, Boeing, to L. Matlock, WDOE, on 5-4-95 Mr. Krull, Enclosed is our request for renewal of coverage under Ecology's Baseline General Permit for Discharge of Stormwater Associated with Industrial Activity for The Boeing Company's Boeing Commercial Airplane Renton (including Overmeyer) facility. Please, note that the form is not the standard request form. The standard forms for our facilities were not received by Boeing. In the above referenced telephone conversation J. Nelson, Boeing, informed Linda Matlock, WDOE, that the renewal forms had not been received and requested that new ones be sent to us. All new forms with the exception the form for the Renton facility, which could not be located, were received by us on 5-9-95. A marked up NOI form was supplied instead to be used for renewal for the Renton facility. A copy of Ms. Matlock's cover note is included with the completed form. If there are any questions or concerns regarding this submittal, please contact Joyce Nelson at (206) 965-1403. Sincerely, Varnes V. Medzegian Director Safety, Health, & Environmental Affairs Renton Division enclosure S.F. ROUMNG SLIP 80 SF 80 F OATE TO f a007S � nnatt ;rCP FRAM i MAIL STOP PFtCrt{Ff1 !�q-�7• S 1N/ T /I ❑ For Ac:t�^ �r Your Recuest Ej Per Cur Conversation For Aocroval L7Reac ano Return C Reao 3 Route;o Files CI For Signature For Your intarmation L7 For Your Comments /A�' n L L Fi t;Cv� r,/�4c.��F i� � R E N E W A L LN -0 T I C E Pem�itNo. 503-000232 NOTICE OF INTENT Uel No.Tax 9"oa')cra,; DOR No. wrswiwcrro srIrr For Baseline General Permit to f&t*°"jy one Item EF Cr I r L r o r G 1Y Discharge Stormwater Associated with 1• E)dsting Facility 2 ❑ New Facility Start-up date Industrial Activity 3. ❑ Change oflnformaticn (attach e=ianatory letter) (Please print In Ink or type) I. OPERATOR If. OWNER/REPRESENTATIVE OF FACILITY Name Name BCAG-Renton Plant The Boeing Company Mailing Address Maiiing Address P.O. Box 3707 MIS 63-41 P.O. Box 3707 MIS 63-41 City Zip+4 I City Zip+4 Beattie 98i24-22Ci Seattle 98124-2207 Contact Person Phone No. Contact Person Phone No. Jovice Nelson (206) 965-1403 lJcvce Nelson (206) 965-1403 1I1. FACILITY ADDRESS IV. BILLING ADDRESS: Facility Name ❑ Owner ❑ Facility BCAG- Renton Plant Ooerator ❑ Other(below) Street Address Name BCAG-Renton Division North Sth & Park avenue, North The Boeino Company City Zp+4 Phone No. Address f Renton 98055 (206) 234-1166 P.C. Box 3707 MIS 63-41 County City Zp+4 Phone No. Seattle 98121__-2207 (206) 234-1766 Legal Description (if no address for site) V. RECEIVING WATER INFORMATION A. Does your facility's storrnwater discrarge to:(check all that apply) 1. ❑ Storm sevver system;name of storm sewer system(operator): 2. ❑ Directly to surface waters of Washing n state (e.g., river, lake,creek, estuary,ocean) 3. ❑ Indirectly to surface waters of Washington state 4. ❑ Directly to ground waters of Washington state: ❑ dry weii ❑ drainneld ❑ other 6. Name(s)of receiving water(s): Initial discharge is to an unnamed receiving water? Yes No C. Location of Discharge(s): Quarter Section Township Range VI. INDUSTRIAL ACTIVITY INFORMATION A. SIC Code(s) (Post PRIMARY SIC in No. 1) B. Type of business 1. 3 t 7 2 11 2.13 18 10 10 3. 7 3 8 4 4. airplane manufacturing; laboratories;Photo C. Areas with industrial activities at Iacility: (check all that apply) 1. ❑ Manufacturing Building 6. ❑ Application or Disposal of Wastewaters 2. ❑ Material Handing 7. ❑ Storage and Maintenance of Material Handling Equipment 3. ❑ Material Storage S. ❑ Vehicle Maintenance 4. ❑ Hazardous Waste Treatment,Storage,or Disposal 9. ❑ Inactive Areas Where SignQJcant Materials Remain (Refers to RCRA,Subtitle C.Facikties Cnly) 10. ❑ Access Roads and Rail Lines for Shipping and Receiving 5. ❑ Waste Treatment Storage,or Disposal 11. ❑ Other ECY 020-84(Rev.4r94) (Appendix 4) Boeing Commercial Airplane Group P.O.Box 3707 Seattle,WA 98124-2207 June 2, 1995 R-1150-EJN-95-332 BOE/NG City of Renton , C' rt 200 Mill Avenue South JUN 81995 Renton, WA 98055 C v C:.F RENTOy Er&ineering Dept. Attention: Storm Water Utility Subject: Renewal Notice of Intent (NOI) for the Baseline General Permit for Discharge of Stormwater Associated with Industrial Activities Reference: Letter R-1150-EJN-95-300 with enclosures from L. Babich, Boeing, to City of Renton Storm Water Utility, dated May 23, 1995 After reviewing a copy of the above referenced letter with enclosures, it was discovered that the back side of the Notice of Intent (NOI) we sent to the WDOE was not duplicated. The enclosed NOI is a copy of the completed form with the sections marked out in green as received from Ms. Matlock of the WDOE that was completed and returned to the WDOE. Please, accept our apology for this oversight and any inconvenience that it may have caused. If you have any questions, please contact Joyce Nelson at 965-1403. Sincerely, M. Babich, III Environmental Affairs Manager R-1150 M/S 64-41 enclosure ` R E N E W A L N 0 T T C E Permit No. S03-000232 NOTICE OF INTENT UBI No:Tax TD# 9104256941 DOR No. fark x,swiccsao snare For Baseline General Permit to i. C °"�one item EE CE o'1,E o E 6 3Y Discharge Stormwater Associated with 1 E'°sring Facility 2 ❑ New Facility Start-up date Industrial Activity 3. ❑ Ch(atangeema�orv°etlerl (Please print In Ink or type) I. OPERATOR 11. OWNER/REPRESENTATIVE OF FACILITY Name Name BCAG-Renton Plant The Boeing Company Mailing Address Mailing Address P.O. Box 3707 m/s 53-4I P.O. Box 3707 MIS 63-41 City Zip+4 City Zip +4 Seattle 98124-2-207 Seattle 98124-2207 Contact Person Phone No. Contact Person Phone No. Jovice Nelson (206) 965-1403 lJovce Nelson (206) 965-1403 111. FACILITY ADDRESS IV. BILLING ADDRESS: Facility Name ❑ Owner ❑ Faculty BCAG- Renton Plant Operator ❑ Other(below) Street Address Name BCAG-Renton Division North 8th & Park avenue, North The Boeing Company City Zp+4 Phone No. Address Renton 98055 (206) 234-1766 P.O. Box 3707 MIS 63-41 County City Zip+4 Phone No. Seattle 98124-2207 (206) 234-1766 Legal Description(if no address for site) V. RECEIVING WATER INFORMATION A. Does yourfaality's stonnwamrdischarae to:(check all that apply) 1. ❑ Sloan sewer system,name of storm sewer system(operator): 2. ❑ Directly to surface waters of Washington state (e.g., river, lake,creel,estuary,ocean) 3. ❑ Indirectly to surface waters of Washington state 4. ❑ Directly w ground waters of Washington state: ❑ dry well ❑ drainfiield ❑ other B. Name(s)of receiving water(s): Initial discharge is to an unnamed receiving water? Yes LJ No C. Location of Dfscharge(s): Quarter Section Township Range VI. INDUSTRIAL ACTIVITY INFORMATION A. SIC Code(s)(Post PRIMARY SIC in No. 1) B. Type of business 1. 3 7 2 1 2 3 8 0 0 3. 7 3 8 4 4•� airplane manufacturing; laboratories;photo C: Areas with industrial activities at facility: (check all that apply) 1. ❑ Manufacturing Building 6" ❑ Appication or Disposal of Wastewaters 2. ❑ Material Handing 7. 0 Storage and Maintenance of Material Handling Equipment 3. ❑ Material Storage 8. ❑ Vehide Maintenance 4. ❑ Hazardous Waste Treatment,Storage,oc Disposal 9. ❑ Inactive Areas Where Slgniflcant Materials Remain (Refers to RCRA,Subtitle C Facilities Only) 10. ❑ Access Roads and Rail Lirses for Shipping and Receiving 5. ❑ Waste.,Treatment;Stir rage,or Disposal 11. Cl Other ECY 020-84(Rev.4/94) (Anpendbc 4) D. Addttlort*l Inlotmation Nooded: t. Tb l 83 De of sloe w h Industial avttvfty In aaraa) 2. Total impervious iron(irrofudtnq m*fbp*) An e.aoa) y~J ❑ No 3, Has*swmwater polution prova+rrdan pW boon dayslop ? Ye 4. Ara saaormwater dsaharye data w mlabte? ❑ yes D No 5. At*dita ayattabaie on impact of stornTwww on wear quaJlty or sedJmonts? ❑ Yos ® No VIi. MATEMAL HANDUNaf)AANAGEMSNT PRACTICES A. Typos of midarints han6pd arxvor stored outdoors:(0*ott ml hurt appty) 1. ❑ soJvantt 4. ❑ Plating Products a. ❑ PatntxJcaathgs 2. D Some Mo%1 5, Q Pastfdda' 4. D Woocttrsating Products 3. ❑ Petroloum or Petrochemical Products $. © Hazardous Wastes irJ. ❑ Otiror Toxics(R*aae ist) 7. ❑ Adds or AJ}caflBs 8. Idonttfy axfstfnq rnw-&&govern practloas ornp�oyed io reduce pollutants h tndusrrtai swm waver dts;c�vs: (dwok*J that appty) 1 1. r1..i URMabr Separator _ 4, 0 Surface 1.aactsa0a CoBeotion i. ❑ infiJtratbn Buaakis Z. rr:3Z� Care rsent 5 Q Ovs�rtread C.r�vera�w A 9. ❑ operarisna!BMN S. 4.d Spit pm~tton B, �❑1 Racycing/Source Roduodon 14. a Vag+taWn Marsagamont 7. Q D.tantfon J=aoildes t t, ❑ Oti?er(PSeas+a pk) VIII. REGULATORY STATUS (Check all that a A. ❑ NPDES Penns C. ❑ AJr Nodoo of oonztruC n, Perm or order Pomit No. r a. ❑ Stau wants Dischwge Pvrmt Q. t3, EPA 1-11= ous Wlssty ID No, Porn-it No. IX. STATE ENVIRONMENTAL POLICY ACT(SEPA) (A.Wlesortty to NEW INDUSTRIAL FACIU7TES) Has$EPA rrviaw boon oomr 0et+ad? U Yea ❑ No ❑ E"n-%X - Typa of SE''r A dooumont: I. ❑ DNS ❑ Rml E33 ._ Aq#rKy N*uf g DNS, Rr+al E;S,or Exen kn: Daw of DNS or Rrw!JAB; `} Are you*wars of an"&I of o-re xdaquaoy of ttn SEP A docus»enr? ❑ Yas ❑ No ` (�)"��P�sso ass: exPiersatz,ry fetfor.) �' X. PURUC NOTICE(A tea onfy to NEW INDUSTRIAL FACILMES) ' �t>ed sffidavlt of TWO pitons? ❑ Yes ❑ hie M. CERTIRCATION OF Pr-RWTTEE(S) '1 oerVry urodor penalty of!ew V1W thds doanrrerrt x-,d ay attachments were prpparod urOw my dreotton or supeM*oo to rx�witty a system designed to assure that qua jMod person 4 propodyga&w and evaluate bl;e lrrforma#on'sutrrr�, Based on rmy iNdry of the porur of persons*ft manage the systcrn, or ff?cso persons cUmcey resporm bit for gott�amV M4 infomaatfon, t�a Infornlatfon subrr:rtFed Is, to tiro bast of my ta�otivledge BrTd b414;ve, &V0,ado, and corrppioto' 1 am awstro ftZat &?Or&are slgrrfrczurt ponatdes for subaftng faE lnfmrnatfon,lndu dhig the passibilty of fine and in pvdsorrraont for knowar9 Nda-dorzs.' (tf Co-Pvfrnrttae) OparEr6of's Ptirtted t rrp: 1 J etas s V. M(eldz e g i a n Omws's Prtrrtod gyro: S4V'AatLxo: Tale: DireuLor, Date, 12 Safety, Hcalth, & Environmental Affairs STATE USE ONLY 2 tJi �,a�.��a�v-e,..7� .�y,..� `�k y„�..n,...v�,,y. 2 ,µ�/� :j���.u''I `a .•i�M j<i�} / GY'•7'��F�� �;. j�%r{„ �'c1�.2. v� .•» n+' .✓��.-'i(��ir �� ��.�`i.;t� �laq.�.,��� <^�oCe� .. .s. s' �,N,\, ,�.GG'w"��\✓1�����'f^sw.e "S s - 1' yY�.�' ,.+ae~��"t '°"• '`"�4 F..vee Y ^„'Ic,,,.Ci �...*ot A 3^•>j •r usiy.Jl ,,,,,.., m., <s.yf a !. l ^`''[' .4"�.. .r�.w�`s.��,?�aw.cey,,•,,,o„� f:3' h3's,��. .u<.o i CITY OF RENTON MEMORANDUM DATE: May 20, 1992 TO: Gregg Zimmerman Tom Kriss Lenora Blauman FROM: Ron Straka X� SUBJECT: The Boeing Company's Customer Service Training Center Project Code Modification/Alteration Request The Surface Water Utility has reviewed the Boeing Company's code modification/alteration request for the Customer Service Training Center (CSTC)project as allowed under Ordinance No.4342. The Boeing Company has requested code modification/alteration to the City of Renton Storm and Surface Water Drainage chapter 4-22. The code modification/alteration request (see attached documents)pertains to the portions of the City adopted 1990 King County Surface Water Design Manual (KCSWDM) Core requirement No 3 (biofiltration requirement) and Special Requirement No. 6 (coalescing plate oil/water separators)surface water management standards. The Surface Water Utility approves of the requested code modification/alteration request based upon the information provided by the Boeing Company (see attachments). This information includes a technical letter from Dr. Richard R. Horner who teaches at the University of Washington's Environmental Engineering and Science Department. Dr. Horner a nationally respected expert in the field of water quality and resource engineering. Dr Horner reviewed the code requirements for the Boeing CSTC project and estimated the pollutant removal that would be obtained. He then reviewed the proposed storm and surface water management facilities design for the Boeing CSTC and estimated the percentage of pollutant removal that would be achieved by the Boeing system. This comparison shows that the proposed Boeing CSTC storm and surface water management plan will remove more pollutants than the code requirements would for the selected parameters. The Surface Water Utility approves the code modification/alteration request based upon this evidence and accepts the conceptual drainage plan for the Boeing CSTC project. The request demonstrates that the proposed design meets the intent of the code, will accomplish equivalent pollutant removal as required by code(actually exceeds code requirements), it will equally protect the environment and satisfies the other requirements of Ordinance No 4342 as discussed in the formal request. r As allowed by Ordinance No 4342, the following conditions of this approved code modification/alteration request must be complied with by the Boeing Company as specified in the conditions. The conditions of the code modification/alteration request are as follows: 1.) The applicant (The Boeing Company) shall develop a Water Quality Monitoring and Assessment Plan to be approved by the City of Renton Surface Water Utility. The Utility recommends that the Boeing Company receive direction from Dr.Horner in the development of the Water Quality Monitoring and Assessment Plan. This condition must be complied with prior to the issuance of the CSTC projects construction/building permit. 2.) The applicant shall implement the approved monitoring plan with continuous monitoring for a period of time as specified in the approved plan based upon Dr. Homer's recommendations. The water quality monitoring shall start following the completion of construction at the time of the projects Final Occupancy Permit issuance(CSTC building). 3.) Upon completion of the approved water quality monitoring period, the applicant shall provide within two months the City of Renton with technical report which documents the results of the water quality monitoring and assess the effectiveness of the proposed systems pollutant removal rate for comparison with code pollutant removal rates. If the proposed CSTC storm and surface water systems pollutant removal rates are less than what the code requirement pollutant removal rates are, then the Boeing Company shall install the required coalescing plate oil/water separators, or propose alternate measures which may be subject to additional conditions by the City of Renton Surface Water Utility. 4.) The applicant (Boeing)shall provide the City of Renton with a bond that is valid for the duration of the approved water quality monitoring duration period plus six months,which is equal to 100% of the cost to design/construct/install the projects required coalescing plate oil/water separators. These conditions are justified in order that the proposed CSTC storm and surface water management system works as certified by the applicants engineer and to ensure protection of the public's safety and health as well as the environment. If you have any questions regarding this subject,please contact me at (206)277-5547. ` Boeing Commercial Airplane Group P.O.Box 3707 Seattle,WA 98124-2207 May 11, 1992 Ms. Lenora Blauman City of Renton DOE/N" 200 Mill Avenue South Renton, WA 98055 Re: Boeing Customer Services Training Center ("CSTC") / Administrative "Variances" Required for Storm and Surface Water Drainage System Dear Lenora: As you know, City of Renton Ordinance No. 4342 ("Ordinance") amends the Stormwater Drainage Section of the City's Building Regulations to provide that any material or method of construction may be used to construct storm and surface water drainage facilities, so long as that material or method has been approved by the Planning/Building/Public Works Department Administrator. The Administrator's approval must be based on a finding that the material or method of construction proposed is "at least the equivalent of that prescribed in [the Renton Municipal Code] in suitability, strength, effectiveness, durability, safety, maintainability and environment protection, " which finding must be supported by evidence provided by the applicant. In general, the storm and surface water drainage facilities planned for the CSTC conform to the Core and Special Requirements of the King County Surface Water Design Manual ("Manual") . However, Boeing proposes to utilize alternative methods of construction with respect to Core Requirement No. 3 (regarding run-off control) and Special Requirement No. 6 (regarding coalescing plate oil/water separators) . I. SYSTEM REQUIRED BY MANUAL; CORRESPONDING PERFORMANCE STANDARDS Core Requirement No. 3 requires the use of biofiltration swales for projects that (a) include more than 5, 000 square feet of impervious surface and (b) are [03008-0352/SB921290.D OC) Ms. Lenora Blauman May 11, 1992 Page 2 subject to vehicular use. Special Requirement No. 6 states, in part, that if a proposed project will include more than five acres of impervious surface that will be subject to more than 2, 500 vehicle trips per day, a coalescing plate oil/water separator is required. BOE/NG Thus, the system required by the Manual requires a conveyance system (a series of pipes and catch basins) to collect flow from roadways and parking lots. After collection, the flow would pass through an oil/water separator (using coalescing plate technology) , then into a system of biofiltration swales, and finally into a three- stage wet pond system. Dr. Richard R. Horner has reviewed the system described above and estimates that it will achieve the following removal rates: TSS=Total Suspended Solids TP=Total Phosphates MATERIAL REMOVAL RATE TSS and Pb 67-870 Cu and Zn 48-680 TP 320 II. ALTERNATE SYSTEM PROPOSED FOR THE CSTC; CORRESPONDING PERFORMANCE STANDARDS The storm and surface water drainage system designed for the CSTC includes a conveyance system that incorporates twice the normal number of catch basins - a greater number of catch basins creates more sediment trap area. All catch basins are located off-line to prevent stirring of sediments collected in the catch basins during storms. In addition, each catch basin is provided with an elbow to trap floatables and to act, in part, as a gravity oil/water separator. The conveyance system transports the flow to a first stage wet vault (grit chamber) that provides some additional gravity oil/water separation, then into second and third stage ponds (which contain much greater surface area and volume than required by Code) and [03008-0352/SB921290.Doq 5/11/92 Ms. Lenora Blauman May 11, 1992 Page 3 then through a wet biofiltration swale-stream system to the outfall at Springbrook Creek. Dr. Horner has reviewed this system and, discounting the benefits of the catch basins and the grit chamber, reports the following expected removal rates: BOE/.NG MATERIAL REMOVAL RATE TSS 99% Pb 95-96% Cu and Zn 65-73% TP 61% These removal rates are significantly higher than those provided by the system required by Code. In particular, TSS removal is at. least 12% greater than that provided by the Code system; Pb removal is at least 8% greater; Cu and Zn removal is at least 5% greater; and TP removal is 29% greater. In addition, the proposed system meets the Ordinance' S objectives of safety, function, appearance, environmental protection and maintainability as follows: A. Safety. All culverts over 24 inches in diameter are designed with protective cages in place around entrances and exits to prevent entry by children. This measure exceeds Code requirements. The existing sill to the site utilizes bioengineering slope-stability techniques to enhance safety and limit the possibility of failure. All other Code requirements for safety are met. B. Function. Comparable function is demonstrated by the removal rates described above and the reduction of outflow rates by over 50% for all storms, not only two- and ten-year events as required by Code. C. Appearance. The stormwater system is viewed as a ' landscaping amenity; consequently, its appearance is better than required by Code. [03008-0352/Ss921290.DOCI 5/11/92 Ms. Lenora Blauman May 11, 1992 Page 4 D. Environmental Protection. The removal-rate comparison set forth above indicates that the proposed system exceeds the standard of environmental protection required by Code. E. Maintainability. Because this project is BOE/NG located on private property and the storm drainage system is viewed as a landscaping amenity, Boeing will retain maintenance responsibility. Thus, there will be no maintenance costs of the system to the City. F. Effect on Neighboring Properties. Downstream properties will be benefitted by the reduced outflow rates from the site for all storm events; the project will not be injurious to other properties. For your information and review, I attach relevant sections of the Manual; a comparison of existing versus post-development runoff conditions excerpted from the TIR prepared for the CSTC; and a copy of a letter from Dr. Horner to Dave Benson of Sverdrup outlining the results of Horner's system comparison. Please do not hesitate to contact me if you have questions regarding our requested administrative variances. tti Ver t /art rs, M. S Program Manager Org 6-4067, MS 6Y-50 Phone (206) 393-7101 Enclosure cc: R. E. McCaan ' Perkins Coie R. H. Wicklein (03008-0352/SB921290.DOC] 5/11/92 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL 1.2.3 CORE REQUIREMENT #3: RUNOFF CONTROL. Proposed must projects provide runoff control through a combination of peak rate runoff control facilities and on-site biofltration measures as described below. Peak Rate Runoff Control Proposed projects must provide peak rate runoff control to limit the developed conditions peak rates of runoff from specific design storm events not to exceed the pre-development peak rates for the proposed project site 'existing conditions"as described below. Three basic methods for peak rate runoff control are possible: detention, retention, and Infiltration. Detention is the collection and temporary storage of surface water (typically over several hours) with the outflow rate restricted—usually to the pre-developed outflow rate. Retention Is the collecting and holding of surface and stormwater with effectively no surface outflow (outflow occurs by evapotranspiration). Infiltration is the soaking of surface water into the ground (typically for several hours or days). Infiltration not only reduces or eliminates surface runoff, but also helps to maintain the hydrologic balance of the surface water system. Infltration can limit erosion and recharge groundwaters that supply water to wetlands, streams, and wells. Preserving Infiltration after development is by far the most effective mechanism in preventing adverse Impacts to the surface water system. Because of these benefits, King County encourages the use of Infiltration systems for runoff control where the appropriate soil conditions exist. Proposed project peak rate runoff control must be located on-site. An exemption from on-site peak rate -runoff control may be granted for the special conditions specified at the end of this core requirement section. Blofiltration Proposed project runoff resulting from more than five thousand square feet of Impervious surface, and subject to vehicular use or storage of chemicals, shall be treated prior to discharge from the project site by on-site biofiltration measures as described in Section 4.6.3 in Chapter 4. The blofiltration design flow rate shall be the peak rate of runoff for the 2-year 24-hour duration design storm event. Note, biofiltration facilities installed following peak rate runoff control facilities may be sized to treat the allowable release rate (pre-developed) for the 2-year 24-hour duration design storm event for the peak rate runoff control facility. Blofiltration facilities installed prior to peak rate runoff control facilities shall be sized based on the developed conditions. Proposed Project Site 'Existing Conditions' In performing the analysis for the design of runoff control, it Is essential to first determine the proposed project site 'existing conditions' from which the pre-development runoff rates can be computed for specific design storms. Existing conditions are not always synonymous with those of the natural, totally undeveloped site. In some instances substantial modifications (such as diversions, piping, clearing, and grading) have already increased and altered surface water runoff leaving the site, but no permit, nor accompanying engineering plan, was ever approved. In other instances, an approved drainage system exists and the existing system must be analyzed for its performance. There are two definitions for proposed project site "existing conditions' depending on the site. Sites with Existing Approved Drainage Systems: The proposed project site "existing conditions' are defined as those that occur with the existing drainage facilities constructed per approved permits and engineering plans. The current performance of existing drainage and detention facilities shall be determined by using the analysis methods described in Section 3.5 in Chapter 3. Sites with No Existing Approved Drainage Systems: The "existing conditions' are defined as those that existed prior to May 1979, which is the date of publication of "Requirements and Guidelines for Storm Drainage Control in King County" by the King County Public Works Department's Hydraulics Division, the 1.2.3-1 1/90 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL Peak Rate Runoff Control Performance Curve A `peak rate runoff control performance curve' plots the allowable peak runoff rates for a range of design storm frequencies, as illustrated in Figure 1.2.3A the 'Standard Peak Rate Runoff Control Performance Curve'. In the absence of other Special Requirements which dictate a more thorough analysis, the BALD Divislon evaluates peak rate runoff control only for the 2-, 10-, and 100-year frequency storm events represented on this curve. Peak rate runoff control facilities must be designed to produce post- development peak runoff rates at or below this curve for the 2-and 10-year, 24-hour duration design storm events. More restrictive runoff control performance curves may be required under conditions specified in the 'Special Requirements' section of this chapter. The post developed runoff for the 100-year, 24-hour duration design storm event shall be routed through the conveyance system and the peak rate runoff control facilities to evaluate any significant adverse impacts downstream (see Sections 1.22 and 12.4). Additional control to reduce the post-developed peak runoff for the 100-year, 24-hour duration design storm event is one mechanism that may be used to mitigate significant adverse impacts downstream. The required performance above the 10-year, 24- hour duration design storm up to the 100-year, 24-hour duration design storm event, therefore, Is dependent upon downstream conditions and how much attenuation the peak rate runoff control facility designed for 2- and 10-year, 24-hour duration design storm events provides for the 100 year, 24-hour duration design storm event. FIGURE 1.23A STANDARD PEAK RATE RUNOFF CONTROL PERFORMANCE CURVE , For the 100-year,24-hour design "s storm event, the peak rate runoff control facility release rate depends on Cn ................... ----...the significance of downstream impacts; L11 -60 - I— •' Q Pre-development peak rates LL (allowable release rates) ' O ' � -- Q ........................................................ vi 10 , U Qv , W Post-development s a. peak rate runoff Q2 ------------- control facility release rates 2 10 100 24 HOUR DESIGN STORM FREQUENCY(YEARS) 1.23-2 1/90 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL Detention Facilities There are two main types of detention facilities: ponds; and, tanks or vaults. The methods of analysis and design standards for detention facilities can be found in Section 4.4 in Chapter 4. Factor of Safety- The design volume of detention facilities used to meet the standard peak rate runoff control performance curve for the 2-and 10-year, 24-hour duration design storm events shall be Increased by a 30 percent factor of safety. This requirement shall be met by increasing proportionally by 30 percent the design detention volume between each 1 foot of storage depth without Increasing the total depth of storage or altering the design control orifice/weir sizing. Detention Ponds: Detention ponds are the most desirable alterative for detention facilities for water quality benefits, relative ease of inspection and access for maintenance. long County encourages the design of multi-purpose detention ponds which can serve the multiple purposes of recreation (such as playgrounds or picnic areas), wildlife habitat (wetlands areas) and aesthetics (landscaping to provide for a natural appearance). Multi-purpose ponds must meet all the requirements of the purposes they are required to perform. In multi-purpose ponds incorporating recreational facilities, the recreational facilities must be designed In a manner compatible with the storm water functions and maintenance standards. Detention ponds may combine the performance requirements of wetponds (see Special Requirement #5 and Section 4.6.2 In Chapter 4). Detention Tanks and Vaults: Detention tanks and vaults are underground facilities for the storage of surface water. Tanks are typically constructed from corrugated pipe and vaults are constructed from reinforced concrete. Tanks and vaults provide less water quality benefit (btofiltratton and biologic activity) than ponds, therefore, biofiltration measures are especially important. Private Parking Lot Ponding: Private parking lots may be used to provide additional peak rate runoff control detention volume for the post-developed peak rates of runoff for design storms greater than the 10-year, 24-hour duration design storm provided that: (1) the depth of water detained can not exceed 1.0 feet at any location in the parking lot; and (2) the minimum gradient of the parking lot area subject to ponding shall be 1 percent; and (3) the emergency overflow path meets the same requirements as for infltration systems. Roof Ponding: Ponding of roofs of structures will be allowed to be used for peak rate runoff control detention volume provided that: ti (1) the depth of water ponded can not exceed 1.0 feet at any location on the roof; and (2) the minimum pitch of the roof area subject to ponding shall be 1/4 inch to 1 foot; and (3) the roof support structure is analyzed by a structural engineer to address the weight of the ponded water, and (4) the roof area subject to ponding Is water-proofed with a method with a minimum expected service life of 30 years. Retention Facilities There are two basic types of retention facilities: ponds and closed depressions. Retention ponds are constructed by a combination of excavation and/or berming. Closed depressions may be established as retention facilities, and in some cases enlarged to accommodate additional surface and stormwater runoff by excavation and/or berming. 123-3 1/40 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL Usually retention facilities will not be a cost effective means for providing peak rate runoff control, but rather are employed to control the increased volume of runoff from a proposed projects as is required by Special Requirement #7: Closed Depressions in Section 1.3.7 of this Chapter. The pre-and post-development peak runoff rates for the 100-year, 7-day duration design storm events are evaluated, along with the standard peak rate runoff control performance curve, when retention facilities are employed in order to control increased volume of runoff from proposed projects. In these cases, retention facilities shall be analyzed and sized using the methods described in Section 3.6 in Chapter 3, and designed using the design standards contained in Section 4.4 in Chapter 4. Note, in some cases, retention facilities will have significant infiltration capability and, in these cases, must also meet the design standards contained in Section 4.5 In Chapter 4. Infittmtton Facilitles Infiltration facilities, as with detention systems, must be sized to meet the required peak rate runoff control performance curve. More restrictive runoff control curves may be required under conditions specified in the 'Special Requirements' Section 1.3 of this chapter. Note, the factors of safety for Infiltration systems are incorporated within the methods of analysis and design standards described in Section 4.5 in Chapter 4. For the design requirements and standards for infiltration facilities see Section 4.5 in Chapter 4. There are many practical limitations on infltration facilities, due to the very slow permeability rates of some soils and the need to prevent contamination of groundwater resources. Because of these practical limitations, long County allows Infiltration facilities only In the following Soil Conservation Service series soils: Arents ('An' only), Everett, Indianola, luaus, Nelton, Pilchuck, Puyallup and Ragnar. A soils report is required for all proposed infiltration facilities to verify the mapped soils series or to classify the series of the soil (if previously unmapped). Soils logs are prepared to provide the data for the report and to Investigate and confirm that the seasonal high groundwater is at least 1 foot below the bottom of a-- proposed infiltration system. Where doubt exists as to the depth of seasonal high groundwater an investigation must be conducted during the winter months prior to permit approval. Infiltration facilities may not be operated until pII proposed project improvements which produce surface runoff are complete, especially revegetation and landscaping. In the case of projects with Individual lots remaining undeveloped, these lots must contain and Infiltrate their runoff through individual sediment traps (see Section 5.4.4.1 in Chapter 5) acting as infiltration ponds as until permanent improvements and landscaping are established. Infiltration facilities must be designed based on infiltration testing and a soils report prepared by a professional civil engineer with expertise in sod engineering. An emergency overflow path must be identified for infiltration facilities and noted on the engineering plan. This overflow path must be analyzed to meet the requirements of Core Requirements #1 (see Section 1.2.1) and #2 (see Section 1.2.2) for the 100-year, 24-hour duration design storm, except Downspout Infiltration Systems (see Section 4.5.1 in Chapter 4). Infiltration facilities may be especially useful in the following circumstances, provided the proper soil conditions are present and all requirements can be met (1) The proposed project discharges to a closed depression. (2) The proposed project discharges to a severely undersized conveyance system that restricts the runoff volume that can be accommodated. (3) The proposed project is in a Critical Drainage Area requiring runoff volume control. 12.3-4 1/90 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL Exemptions From On-Site Peak Rate Runoff Control On-site peak rate runoff control will not be required for a proposed project in the following situations. (1) Neallaible Peak Runoff Rate Increase*: o The proposed project site post-developed peak runoff rate for the 100-year, 24-hour duration design storm event is calculated to be less than 0.5 cis more than the pre- developed peak runoff rate for the proposed project site existing runoff conditions. OR o The project proposes to construct 5,000 square feet, or less, of new impervious surface. *Proposed projects In designated critical drainage areas requiring stricter peak runoff rate or runoff volume controls shall not qualify for this exemption. OR (2) Direct Discharge:** The proposed project will discharge surface and stormwater runoff without on-site peak rate runoff control directly to: A Regional Facility. Direct discharge of surface and stormwater runoff to a regional facility will be allowed If: the facility has been demonstrated to adequately to control the proposed project's Increased peak rate of runoff by an adopted Kng County basin plan or by a detailed drainage analysis approved by the SWM Division; the facility will be available by the time of construction of the project; AND, the conveyance system between the proposed project and the regional facility will be adequate for the proposed project's design peak runoff with no significant adverse Impacts. A Receiving Water. Direct discharge of surface and stormwater runoff to the following receiving waters may be allowed. Proposed projects that require Master Drainage Plans (see Special Requirement #3) shall demonstrate no significant adverse impacts from direct discharge to a river. Cedar River Green/Duwamish River (below river mile 6.0, F.E.M.A.) Puget Sound Lake Sammamish Sammamish River Skykomish River Snoqualmie River Lake Washington White/Stuck River A Lake, Wetland or Closed Depression. See Special Requirement #8: Use of Lakes, Wetlands or Closed Depressions for Peak Rate Runoff Quantity Control, in Section 1.3.8. The applicant should note that many lakes, wetlands or closed depressions will not qualify for this exemption. **Projects qualifying for Direct Discharge must meet the requirements of Special Requirement #5: Special Water Quality Controls in Section 1.3.5. 1.2.3-5 1/90 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL Bypasses Proposed project runoff may bypass the proposed project peak rate runoff control facilities provided that: (1) the proposed project peak rate runoff control facilities are designed to compensate for the controlled project area by limiting the total developed peak runoff rate (both controlled and uncontrolled) to the pre-development peak runoff rates for the proposed project site at the point of discharge, AND (2) both the bypass area and the peak rate runoff control facility discharge to the same subbasin, AND (3) the discharge from the bypass will have no significant adverse impacts on downstream properties. Upstream off-site runoff must bypass the proposed project on-site peak rate runoff control facilities In a separate conveyance system, unless the existing peak runoff rate from the upstream off-site area for the 100-year, 24-hour design storm event is: less than 50 percent of the proposed project site developed conditions peak runoff rate for the 100-year, 24-hour duration design storm event. Tracts The runoff control facilities to be maintained and operated by the King County Department of Public Works (see Section 1.2.6) must be located In a tract or right-of-way created by a legal subdivision and dedicated to King County. Access roads serving these facilities must be also be located In the tract or right-of-way and must be connected to an improved King County road right-of-way. 1.2.3-6 1/90 SD TABL2.XLS Comparison of Existing Versus Post-Development Conditions Storm Pre-Dev Poat=7.Dev ''Charipe Volume pre Dev Post Dev; Pre Dev Closed post pev gosea Closed Depreeslor Event Outflow Qutflow. 'Ppst/Pre Increase Maxlevatlon Max Elevation pepreaslon Depresafan ..; Dlfferentlal cfs NGVD) :(NGVD);.! (NGVq) (feet Water Qualfty 2.60 1.60 62% 19,376 9.06 8.65 11.15 8.91 -2.24 2-Year 24-Hour 22.49 11.55 51% 36,319 10.59 9.15 12.80 10.29 -2.51 5-Year 24-Hour 27.36 14.72 54% 39,168 10.88 9.33 13.19 10.70 -2.49 10-Year 24-Hour 31.41 16.04 51% 39,547 11.12 9.64 13.61 11.17 -2.44 25-Year 24-Hour 35.05 18.84 54% 3 8,64 5 11.34 9.94 14.05 11.62 -2.43 50-Year 24-Hour 35.41 19.23 54% 42,403 11.36 9.97 14.08 11.67 -2.41 100-Year 24-Hour 37.26 22.36 60% 52,575 11.54 10.22 14.43 12.08 -2.35 100-Year 7-Day 36.21 21.26 59% 93,313 11.42 10.13 15.24 (1) 15.20 (2) -0.04 Notes: 1. Outflow of 9.98 cis occurs above elevation 15.00 over the existing NE Meadow Sill. 2. Outflow of 42.88 cfs can occur above elevation 15.00 over the proposed Floodplaln Sill. K� Sverdrup Corporatlon Fini ire )) nn Richard R. Horner, Ph.D. Environmental Engineering and Science 230 N.W. 55th Street Seattle, Washington 98107 (206) 782-7401 February 29, 1992 Mr. J. David Benson Sverdrup Corporation 3300 Carillon Point P. O. Box 97062 Kirkland, WA 98083-9762 Dear Dave: ', This letter- provides .my evaluation of a portion of the stormwater management system proposed for the Boeing Longacres site. I have performed the evaluation as requested by Randall Parsons of the City of Renton; i. e. , by comparing the estimated water quality improvement performance of the proposed system and the system required by the Renton code. This letter covers my analysis and findings for Catchment C (including the occasional drainage from Catchment A that will enter the Catchment C system) . I will provide similar evaluations after you finish your proposed designs for the Catchment B and SW 16th systems. METHODS I estimated the stormwater treatment performance of wet ponds using the methods developed by Driscoll (1983) from data collected on numerous such systems during the U. S. Environmental Protection Agency's Nationwide Urban Runoff Program (NURP) . These methods relate long-term effectiveness (the average over numerous runoff events) to the "volume ratio" (pond dead storage volume to mean storm runoff volume) . The latter term is calculated from mean precipitation quantity, a regional climatological statistic. This ratio has been found to govern the capture of pollutants during the quiescent period between runoff events. The NURP methods also recommend pond surface area in relation to contributing catchment area (the "area ratio") and overflow rate for good performance. The larger the surface area is in relation to the watershed, the better is the operation of pollutant removal mechanisms relying on light and interaction with the atmosphere. Minimizing overflow rate improves short- term removals of the larger solids during and immediately after Mr. J. David Benson February 29 , 1992 Page 2 storms, when the live storage zone of the pond is filled. The recommended maximum overflow rate is 10 cm/hour. I combined the volumes and surface areas provided by second- and third-stage ponds for the analysis. Initially, I took no account of wet vaults, because their overall water quality benefits are very limited as a result of short residence time and excluding light and atmospheric interactions. It should be noted, however, that vaults are useful to increase water storage for release rate control, as presettling chambers to catch the largest particles, as oil/water separators when fitted with appropriate baffling and skimming equipment, and as potential locations for advanced oil/water separators should they ever be needed. I regarded the outlet channel, which is to be at least partially vegetated, as a biofilter and evaluated its performance by using results from the Washington State Highway Runoff Water Quality project (Mar et al. 1982; Horner and Mar 1982; Horner 1988) . Approximations were required because of current uncertainty concerning the final configuration of the channel. I 'reasoned that it should be at least equivalent in performance to the designs recommended by the references cited and required by the Renton code based on the King County Surface Water Design -- Manual- (King County Surface Water Management Division 1990) . The basis for my reasoning is that the channel will have greater size, and therefore water residence time, than biofilters designed strictly according to the requirements, although some of the cross section may not be vegetated. I recommend that the design include native hydrophytic vegetation over the full width and length of the channel for the maximum water quality benefits. I analyzed performance in terms of the expected removal efficiencies for the following pollutants: total suspended solids (TSS) ; total phosphorus (TP) ; and the metals lead (Pb) , copper (Cu) , and zinc (Zn) . The NURP data suggest that removals of total Kjeldahl nitrogen (TKN) and chemical oxygen demand (COD) in a wet pond are similar to those of Cu and Zn, but no basis exists to evaluate trapping of those pollutants in a biofilter. TP removal by biofiltration is seasonally variable because of the annual cycling of vegetation through a growth period, when nutrient uptake occurs, and a death and decay phase, when stored nutrients are released. Although these losses through release could partially be avoided by a fall harvesting program, it is most prudent to consider biofiltration to provide no net TP capture over a full annual period for the current analysis. The applicable Renton code requirements and the proposed design for Catchment C involve a wet pond and biofilter in series. Data are available in the references cited earlier to estimate the performance of the two elements in the sequence separately. It is reasonable to assume that in a series arrangement, however, the second device in line will not perform e Mr. J. David Benson February 29 , 1992 Page 3 at the same level as if it were alone, because the pollutants that are easiest to remove will have already been captured. The available research provides no basis to establish the loss in efficiency of the second element. To compare on the same basis a treatment system required by the code with the system proposed, the analysis assumed two "penalty" levels for the second device: 25 and 50 percent. Therefore, the overall efficiency of the series (Es, as a fraction) was estimated as: Es = 1 - (1 - El) (1 - xE2) ; where El = efficiency of element 1 (as a fraction) , E2 = efficiency of element 2 (as a fraction) , and x = the efficiency remaining after imposition of the "penalty" (0. 75 or 0.50) . Efficiency as a percentage is 100 times the fractional efficiency. ANALYSIS OF CATCHMENT C Code Requirements From the water quality standpoint, the characteristics of Catchment C make it subject to Core Requirement 11 and Special Requirements 95 and #6 in the King County Surface Water Design Manual. Core Requirement #1 mandates peak runoff Sate control, plus biofiltration as a result of having > 5000 ft of impervious area subject to vehicle use. Special Requirement #5 specifies a wet pond for treatment based on > 1 acre of impervious area subject to vehicle use and discharge to a Type 1 or 2 stream within 1 mile. The requirement further stipulates that the pond surface area be no less than 1 percent of the contributing impervious area and have a volume that is, at least equal to the mean annual runoff volume (i. e. , the volume ratio should°�be at least 1) . Special Requirement 96 mandates a coalescing plate oil/water separator because of the anticipated > 2500 vehicle trips per day. Therefore, the code requires a biofilter and a wet pond (in either order) and a coalescing plate oil/water separator. I based the estimated treatment efficiencies for the wet pond according to the minimum code requirement (a volume ratio of 1) . The efficiencies differ somewhat depending on which element is assumed to be first and the efficiency penalty assumed for the second element. I calculated them for both sequences and for penalty assumptions of 25 and 50 percent and estimate them to be in the following ranges: TSS and Pb--67 - 87% TP--32% Cu and Zn--48 - 680 Coalescing plate oil/water separators are meant for industrial applications where influent oil concentrations are consistently larger than generally found in urban runoff. They t ► Mr. J. David Benson February 29 , 1992 Page 4 are capable of reducing oil and grease concentration to 15 mg/L (Horner and Wonacott 1985) . General urban and even highway runoff usually contains lower concentrations than this performance limit. A small amount of data (Horner 1988) indicate that biofilters can reduce the usual runoff concentrations to a much lower level (< 5 mg/L) . Therefore, a coalescing plate separator would serve mainly as a pretreatment device and a trap for accidental spills in a system also containing a biofilter. Proposed System The stormwater system proposed for Catchment C consists of four wet vaults, two second-stage ponds, a third-stage pond (the large lake) , and an outlet channel. The two stages of ponds will provide a very large capacity and long water residence time to treat entering stormwater. Based on the volume ratio represented by the second- and third-stage ponds (24.7) and the two assumptions for the efficiency penalty for the outlet biofiltration channel, I estimate that. the following treatment efficiencies, substantially higher than expected for a system meeting minimum code requirements, can be attained if the system is installed as designed and maintained in .the same condition during operation: TSS--99% TP--61% Pb--95 - 96% Cu and .Zn--65 - 73% Additional comparisons with the system required by the code involve the area ratio and overflow rate. While the minimum requirement for pond surface area is l percent of the contributing impervious area, the proposed pond system will occupy an area equal to 21.2 percent of the Catchment C impervious area and 8.8 percent of the total 76.36 acres i'h the current project. Overflow rates for the proposed system will be only about one-tenth of those that would occur in a system designed according to minimum code requirements. Even within the period of maximum overflow during storms, the proposed system will have rates below the NURP recommendation most of the time. Only with storms greater than about the 2-year, 24-hour event will the short-term overflow rate exceed that recommendation. In contrast, the minimum system would have rates above that level during most storms. The analysis described is based on the runoff contributions expected from Catchment C itself. On occasion drainage will also enter the third-stage Catchment C pond from Catchment A. At a maximum rate of 18 cfs, this contribution will not even begin until an event sized somewhere between the 50- and 100-year, 24- hour level. With the very large capacity of the proposed system and the relative rarity of this extra flow, I do not consider it to detract significantly from the expected performance of the system. Mr. J. David Benson • February 29, 1992 Page 5 Your design proposes eliminating the coalescing plate oil/water separators required by the code. I believe that there will be no loss of protection from oil pollution for the following reasons. The proposed system does include T-section separators in catch basins and baffling in wet vaults for oil separation. These devices will serve as protection against accidental spills and pretreatment ahead of the wet pond/biofilter system in much the same way as coalescing plate separators would. In either situation most of the oil captured from routine runoff would occur in the biofilter. While a coalescing plate separator is more effective than the proposed devices, its capabilities are rarely needed at this type of site. The huge capacity of the pond system will provide further buffering of the receiving water from the effects of oil releases. I will provide my assessments of Catchment B and SW 16th by letter as soon as I receive your proposed designs. I will also forward the list of references cited in both letters at that time. Meanwhile, do not hesitate to call if you need anything additional. Sincerely, Richard R. Horner CITY OF RENTON MEMORANDUM DATE: February 18, 1992 TO: Lenora Blauman VIA: Vi Richard J. Anderson FROM: Randall Parsons STAFF CONTACT: Ron Straka SUBJECT: Boeing Customer Service Training Center (CSTC) Develop- ment Project Conceptual Drainage Plan Review Comments The Stormwater Utility has reviewed the above-referenced project's conceptual drainage plan. The following is the Utility's comments regarding the proposed development project: 1 . The conceptual drainage plan for the project must be approved prior to the Site Plan Approval Hearing. The conceptual drainage plan approval will be dependent upon the approval of the requested stormwater code requirement modifications. Otherwise, the City of Renton Storm and Surface Water Drainage Ordinance requirements must be satisfied. 2. Information must be provided which demonstrates the requested stormwater code modifications (i.e. the proposed three stage wetpond and associated on- site stormwater management system) will provide the same level of water quality treatment benefit as the biofiltration, wetpond, coalescing plate oil/water separator system would as required by the Stormwater Utility Drainage Ordinance. 3. To facilitate review of the project a Composite Utility Plan should be included. A Composite Utility Plan is typically required at the time of building plan review and is usually required for a project of this magnitude. The Composite Utility Plan should consist of the Site Plan with all of the utilities overlay on the plan at a scale (preferable 1 " = 100' or 200') which will fit on a standard drawing sheet size of 22" x 34". Lenora Blauman Boeing CSTC Development Project Page 2 4. SW 16th Street drainage requirements: The storm drainage system design for SW 16th Street improvement must be based upon the City Transportation Division's approved right-of-way section width. The improved street storm system must satisfy the Stormwater Utility Ordinance requirements for water quantity and quality control. The improved street storm system should include at a minimum: 1) Detention, unless it can be shown that the street improvement is exempt; 2) Biofiltration; 3) Wetpond(s)/Wetvault; and 4) The street conveyance system must be sized in accordance with code requirements. The improved street stormwater management facilities must be either located within the street right-of-way (which may require dedication of additional right-of-way for the facilities) or the improved street runoff can be incorporated into the on-site stormwater management system. The Tukwila Nelson Place/Longacres Way storm interceptor, if constructed, must be a separate system from the SW 16th Street storm system, unless the connection of the SW 16th Street system is approved by the City of Tukwila and the requirements of the Stormwater Utility is satisfied. If connection of the SW 16th Street system to the Tukwila Interceptor is allowed, it must be demonstrated that the system will function in accordance with the Stormwater Utility code requirements and will not result in flooding of the street. 5. A detailed description explaining how the on-site compensatory storage requirement is being satisfied (i.e. pre-developed and post-developed flood storage volumes at corresponding elevations). 6. A formal submittal requesting code requirement modifications for the proposed project must be submitted no sooner than March 9, 1992 for consideration under the revised Section 4-22-16 of Chapter 22 of the City code. D:92-1 40:RJS:ps DEPARTMENT OF PLANNING/BUILDING/PUBLIC WORKS ENVIRONMENTAL CHECKLIST REVIEW SHEET REVIEWING DEPARTMENT: S+0&Xv1 0J DATE CIRCULATED: 01/24/92 COMMENTS DUE: 02/07/92 APPLICATION NO(S): ECF;SA;SM;V-006-92 PROPONENT: Boeing Commercial Airplane Company PROJECT TITLE: Boeing Commercial Airplane Customer Service Training Center BRIEF DESCRIPTION OF PROJECT: The Boeing Company is seeking site plan approval and substantial shoreline development permit for the development of a training center complex (CSTC) to provide specialized flight simulation instruction for airline transport pilots. The development is proposed to include a 600,000 square foot training facility, two utility support structures (32,000 square feet), 800 +/-parking spaces, introduced landscaping, and preserved natural environment, and enhanced wetland areas. The complex is anticipated to employ between 900 - 1100 staff and to train between 650 -800 students per session. The subject property is composed of seven tax lots totalling approximately 50.71 acres. The site was historically connected with Longacres Park Raceway, but parcels have been segregated under King County regulations. The site currently houses some structures which serve the raceway. LOCATION: Longacres Drive, south of 1-405 and north of S.W. 19th Street (if extended) SITE AREA: 50.71 acres BUILDING AREA (gross): 632,000 sf IMPACT REVIEW ON ENVIRONMENTAL ELEMENTS: PROBABLE PROBABLE MORE MINOR MAJOR INFORMATION IMPACT IMPACT NECESSARY 1. Earth 2. Air 3. Water 4. Plants X 5. Animals k 6. Energy& Natural Resources 7. Environmental Health 8. Land & Shoreline Use 9. Housing 10. Aesthetics 11. Light & Glare 12. Recreation 13. Historic & Cultural Preservation 14. Transportation 15. Public Services 16. Utilities envnrsht DEPARTMENT OF PLANNING/BUILDING/PUBLIC WORKS DEVELOPMENT APPLICATION REVIEW SHEET APPLICATION NO(S)..- ECF;SA;SM;V-006-92 PROPONENT: Boeing Commercial Airplane Company PROJECT TITLE: Boeing Commercial Airplane Customer Service Training Center BRIEF DESCRIPTION OF PROJECT: The Boeing Company is seeking site plan approval and substantial shoreline development permit for the development of a training center complex (CSTC) to provide specialized flight simulation instruction for airline transport pilots. The development is proposed to include a 600,000 square foot training facility, two utility support structures (32,000 square feet), 800 +/- parking spaces, introduced landscaping, and preserved natural environment, and enhanced wetland areas. The complex is anticipated to employ between 900 - 1100 staff and to train between 650-800 students per session. The subject property is composed of seven tax lots totalling approximately 50.71 acres. The site was historically connected with Longacres Park Raceway, but parcels have been segregated under King County regulations. The site currently houses some structures which serve the raceway. LOCATION: SEC: TWNSHP: RNG.- Longacres Drive, south of 1-405 and north of S.W. 19th Street (if extended) TO: PUBLIC WORKS DIVISION SCHEDULED TAC DATE: 02/18/92 ENGINEERING SECTION TRAFFIC ENG. SECTION �f UTILITIES ENG. SECTION FIRE PREVENTION BUREAU POLICE DEPARTMENT DEVELOPMENT SERVICES DIVISION CONSTRUCTION FIELD SERVICES DEVELOPMENT PLANNING PLANNING &TECHNICAL SERVICES PARKS AND RECREATION DIVISION OTHERS: COMMENTS OR SUGGESTIONS REGARDING THIS APPLICATION SHOULD BE PROVIDED IN WRITING. PLEASE PROVIDE COMMENTS TO THE PLANNING DIVISION BY 5:00 P.M. ON FEBRUARY 7, 1992. de ht Boeing Commercial Airplane Group -y A-� _'i ' P.O.Box 3707 Seattle,WA 98124-2207 >V �� °�' W #_ May 14, 1996 Ell 14 AY 17 1996 R-1150-EJN-96-209 CITY OF RENTGN1 Engineering Dept Mr. Ron Straka P,�, Stormwater Management Division City of Renton 200 Mill Avenue South Renton, WA 98055 BOE/A/G Subject: 4-01 Variance Discharge Monitoring References: 1. Letter number R-1150-EJN-96-035 from L. Babich, Boeing, to R. Straka, City of Renton, dated 1-25-96 2. Telecon with J. Nelson, Boeing, to R. Straka, City of Renton, on 5-14-96 Dear Mr. Straka, As discussed in the above referenced telephone conversation (Reference 1), we are withdrawing our request regarding the 4-01 parking lot monitoring (Reference 2). When this request was initiated, it was our intent to work with you to resolve the issue in time to eliminate or reduce the 4-01 parking lot monitoring by the required first quarter monitoring date of 1996. However, due to the unforeseen long absence of the Environmental Administrator that was assigned to this project, it was not possible to meet this goal. With only four (4) monitoring periods remaining on the variance (our last monitoring period under the 4-01 Parking Lot Variance will occur the first quarter of 1997), we feel that the benefits to us in pursuing the original request are minimal. We appreciate your help and willingness to work with us on this project. If you have any questions, please, contact Doris Turner at 965-2703. Sincerely, L. Babich, III Environmental Affairs Manager R-1150 63-41 Nat �— CITY OF RENTON "u Planning/Building/Public Works Department Earl Clymer, Mayor Lynn Guttmann,Administrator September 3, 1992 Mr. Mike Giseburt R.W. Beck and Associates, Inc. 2101 Fourth Avenue - STE 600 Seattle, WA 98121-2375 SUBJECT: Boeing CSTC Facility Floodplain Analysis Review Comments Dear Mr. Giseburt: The City of Renton Surface Water Utility has reviewed the Boeing CSTC facility floodplain analysis prepared by R.W. Beck and Associates Inc. as part of the East Side Green River Watershed Consultant contract CAG 90-033 Addendum #4, Task #10. Our comments are enclosed for your review. Please revise the Boeing CSTC floodplain analysis report to address our comments. Once the report has been revised, please provide four copies of the final report. Task 10 of consultant contract CAG 90-033 Addendum #4 will be completed upon our acceptance of the revised final Boeing CSTC facility floodplain analysis report. If you have any questions regarding the enclosed comments, please contact me at (206) 277-5548. We appreciate the good work performed in your review of the Boeing CSTC floodplain analysis verifying their compliance with City standards and codes. Sincerely, Ronald J. Straka, Engineering Supervisor Surface Water Utility C:DOCS:92-672:RJS:ps CC: Gregg Zimmerman Enclosures 200 Mill Avenue South - Renton, Washington 98055 R.W. BECK AND ASSOCIATES 2101 Fourth Avenue,Suite 600■Seattle,Washington 98121-2375■USA Telephone(206)441-75000 Fax(206)441-4964 Consulting,(206)441-4962 Engineering Telex 4990402 BECKSEA WW-1159-BAl-CA July 9, 1992 3023 Mr. Ron Straka, Project Manager Surface Water Utility Engineering Supervisor P� Utility Systems Division City of Renton 200 Mill Avenue South Renton, WA 98055 Dear Ron: Subject: City of Renton Boeing CSTC Floodplain Analysis Review We are pleased to submit this preliminary technical memorandum for your review. The Boeing CSTC proposed stormwater controls meet the FEMA and City requirements, with one minor exception. This exception relates to the delineation of the FEMA floodway on the site improvement plans and is discussed in Section III. This memorandum also describes the differences between the Springbrook Creek FEMA floodplain elevations versus the flood elevations predicted under the East Side Green River Watershed Plan. If you have any questions, please contact me at 727-4607. Very Truly Yours, R. W. BECK AND ASSOCIATES Mike Gise rt Project Manager Boston,MA■Columbus,NE■Denver,CO■Indianapolis,IN■Minneapolis,MN Nash,ille,TN t Orlando,FL■phoenix,AZ■Sacramento,CA■Seattle,%VA • The volume of runoff from the project to any off-site closed depression must not increase, except as allowed under the condition of special Requirement number 8, Use of lakes, wetlands or closed depressions for peak rate runoff control. For closed depressions, Special Requirement number 7 also requires the analysis of the downstream impacts from the 2-, 10-, and 100-year, 24-hour ' duration, and the 100-year seven day duration design storm events. _ Analysis. The TIR considers the CSTC facility as a closed depression because (Afk �' high Springbrook Creek elevations (pe FEMA) can prevent outflows from the ioo Y" Rik c�oD site.:i However, when considering that the maximum water surface elevation of �G 9� Springbrook Ceek is only approximately 11 per the ESGRW Plan results, the CSTC facility c uld be considered as having only a restricted outlet instead of an outlet which can prevent ouflows. The City may wish to review this-issue to d terinine the a � pplicability f this r uirement: �E�tA- In any case, the CSTC facility satisfies the criteria required in the closed depression analysis. The first requirement states that when a closed depression is contained solely on a project site, the volume of rainfall previously contained by the closed depression must be retained in dead storage on-site. This criteria is met because there is no pre-development storage volume which is solely contained on the site. Under pre-development conditions, stormwater is temporarily stored on- site during a flood but is allowed to drain freely once Springbrook Creek recedes. The second criteria states that the volume of runoff from the project to any off-site closed depression must not increase, except as allowed under the conditions of special requirement number 8. The CSTC site discharges to Springbrook Creek which is generally not a closed depression, therefore, this criteria is also met. It should be noted that although Springbrook Creek does have a restricted outlet (due to the GRMA), such restrictions have occurred so infrequently that it should not be considered a closed depression. Alternatively, if Springbrook Creek were considered a closed depression, the CSTC would still satisfy this criteria. This is because the TIR predicted a post-development condition increase in runoff volume of 1.3 and 2.1 acre-ft for the 100-year 24-hour event and the 100-year 7-day event respectively. At the same time, the proposed storage facilities provide • approximately 20 acre-feet of storage over pre-developed conditions (at elevation 12). IThe TIR included the analysis of impacts to the downstream system i.e. the 2- p Y ( e , 10-, and 100-year, 24-hour duration, and the 100-year seven day event). In all cases but one, the post-development peak flow rates discharging to Springbrook Creek were lower than pre-development rates. An error was discovered in the one case predicting a higher post development flow, and this simulation was re- 1 ts9wwo.s88 12 07/09/92 r Post-development Percent of Area (Subbasin C) Impervious 35 Pervious, Ur (D group) 56 Pervious, Py (B group) 7 Pervious,Ur (C group) 2 Should future plans include directing stormwater from the south portion of the L.ongacres race track to the CSTC storage facilities, additional soils investigations to determine the runoff characteristics of the Ur soils would be recommended. E. Conclusions/Recommendations Based upon our review of the TIR and associated information, the CSTC satisfies the FEMA and City requirements for development in the floodplain provided that the floodway be illustrated on the site improvement plans (Special Requirement number 9) and it is found that the development proposes no filling in the floodway. The CSTC surface water controls are planned to provide more post-development flood storage than under pre-developed conditions, and the post-developed peak discharges into Springbrook Creek will be less than under pre-developed conditions. Lf l S Gor�/kcrrrc�e� -f C17-Y dF /Zlyra/v 7't- h'.45T Y., G7/Tkn /Qr�r.� Lv<) Srt.�T> Efy�lla/��I c focCe stvv AkaLj S/s �-a irr c l..e G S/�/�/ 7Aln � v5.� � </1�,0'� Try F�sTsi%�E G-4+4- e /�Xifh�rs Grin awee« SY�/�--r. ��r5t� �Pcn dwo f/y Gt�u v C /'GtoLli/ Of-/7.t7� -,-/— /.�/k�ic17� �7• /C.e«/ fi !xx �+.cd<se� ftNj� 1��.ir /, zf c� 5<wU�i/ ljc �orr$/���/�>� (/� h� �yA//c /�'/v0 /IY�//.-a v/cL ,ES6<LLcv /�4�.s� �•s�C� .�o.�' �{v..c �-[clr his wrr� �� qQx.stir} 7hc Li' ty Off' [�A"r /&25 vrt az��„ l�tih��-�G�c���/ �c��[ �L• ,a,,,/ ) f�<<•� �evt�fi-,rc.�c� � � S .9l�v�<<{/ �AS/ / 47-1 tl 1159wwOS88 16 07/09/92 C. SW 16th Street Bridge. The SW 16th Street Bridge was removed and replaced with a wider span bridge since the FEMA work was completed. The new bridge has a clear span of approximately 60 feet compared to the old bridge span of approximately 36 feet with piers This infrastructure change reduces the head loss through the bridge crossing and contributes to the ESGRW Plan findings predicting a lower water surface profile than the FEMA work. y1000 w/tl. 3. Topographic Information There is an apparent discrepancy in the bottom elevation profile in the FEMA study information versus recent surveys by NHC. Figure 3 in the Appendix illustrates the FEMA bottom profile versus more recent survey findings. The discrepancy includes the SW Grady Way box culvert information. The FEMA bottom profile is in some cases almost 3 feet higher than the recent survey information. Using the recent survey findings results in a lower water surface profile of Springbrook Creek. Based on a telephone conversation with the FEMA contractor, the elevations used in the FEMA analysis were determined from a combination of existing channel geometry (based on survey) and proposed future channel geometry based upon the SCS design drawings for the P-1 Channel and the SW Grady Way box culvert which was under construction.a The recent survey information is considered to be more accurate because some of the FEMA elevations were based upon the channel geometry existing prior to construction of the P-1 channel. W�dr T "�� vi4z T/ FEm�r S�Dy 3a.ED fj2�.✓ 4Cc�,2..rTE i5 i f f Using the recent survey fording results in lower predicted Springbrook Creek water surface elevations than the FEMA work. E. Conclusions While several factors contribute to the ESGRW Plan predicting lower water surface elevations than prior FEMA work, the primary reason is believed to be the,increased capacity at the BRPS. Just considering this change alone would result in a significantly lower water surface profile through the lower reaches of Springbrook Creek. The ESGRW Plan effort has examined the Springbrook system with considerable more detail than that of the FEMA study using a sophisticated approach and taking into account infrastructure changes in the drainage system. Consequently, the ESGRW Plan analysis is a considered to be more reliable. Again, it should be noted that, because of the relatively short 26- year record available, and because there was only one event in the period of record where Green River flows significantly constrained the BRPS operation, there is uncertainty in the estimation of Springbrook Creek water surface elevations coincident with high Green River flows. f107-E 7ho /I., L"V y �`�L Fob Ti- C-, 7-A-I- A4, �,h u1, 5/�,�•.�� �t �` r� �*,.vf�su �.¢rR- �R- w��R 5%�a�'T /S yo .4�.•v Y9 9/ is ,A.oa�.> 137Ac 2C yes of min/fvu tiara 'thYno�4G� e- �/7'�� � 6--ukY fEM/� V.S. v 1 'La IV-7 /S'a�. �. c�Y Zc � � �•�•'.c7� Con./ih. a 6�..z� G�y�, /a ` Personal Communication. Shelley Sundgren, Engineer, CH2M Hill. June 24, 1992. F F 1159WWos88 7 07/09/92 09/03/92 15:45 FAX 206 235 2541 RENTON P/B/PW 001 x ACTIVITY REPORT TRANSMISSION OK TX/RX NO. 9891 CONNECTION TEL 94414962 CONNECTION ID START TIME 09/03 15:41 USAGE TIME 04'17 PAGES 6 RESULT OK THE CITY OF RENTON DEPARTMENT OF PLANNING/BUILDING/PUBLIC WORKS RENTON. WASHINGTON 98055 - 2189 PHONE: 235-2631 :y FAX: 235-2541 " ` FAX TRANSMITTAL DATE: TO: - FAX FROM: SUBJECT: 0 S 7( Number of pages excluding cover sheet: R.W.BECK L[EUTEIM W TURS[UTT L AND ASSOCIATES Fourth and Blanchard Building,Suite 600■2101 Fourth Avenue DATE _ y J98 ND. Seattle,Washington98121-2375 �l� ``Z k11 -/.(5;6i 1q ATTENTION File ND. RE: TO tT-r ©r—, ,� oi 2 l�j,c T -L)jf S v� �1-C�c'� f [� 1c IA.)� WE ARE SENDING YOU XAttached ❑ Under separate cover via the following items: Shop drawings ❑ Prints ❑ Plans ❑ Samples ❑ Specifications ❑ Copy of letter ❑ Change order ❑ COPIES DATE NO. DESCRIPTION THESE ARE TRANSMITTED as checked below: ❑ For approval ❑ Reviewed as submitted ❑ Resubmit copies for review For your use ❑ Reviewed as noted ❑ Submit copies for distribution l As requested ❑ Returned for corrections ❑ Return corrected prints LKFor review and comment ❑ ❑ FOR BIDS DUE 19 ❑ PRINTS RETURNED AFTER LOAN TO US REMARKS COPY TO SIGNED:�� It enclosures are not as noted, kindly notify us at once. WW-1159-BA1-AA May 5, 1992 SCOPE OF WORK EAST SIDE GREEN RIVER WATERSHED PLAN CAG 90-033 ADDENDUM #4 Task X The Boeing Company's Customer Service Training Center Flood Plain Analysis Review The Consultant shall conduct the detailed engineering flood plain analysis review of the proposed Boeing Company's Customer Service Training Center(CSTC) stormwater management plan. The plan will be checked for compliance with the City of Renton Standards/codes and Policies which apply to flood plain management along with FEMA Regulations. The consultant will ensure coordination of the Boeing Company's development of the Longacres Customer Service Training Center site with the City of Renton's preparation of the East Side Green River Watershed Plan. The work shall be conducted in 2 phases. The first phase shall include the flood plain analysis review plus a qualitative assessment of the proposed CSTC Stormwater Plan effects on the ESGRWP. The second phase, which is optional and shall not be initiated without prior authorization from the City, includes modifying the FEQ future conditions model to reflect the CSTC stormwater plan. The work shall include the following sub-tasks: 1. Coordination Meetings: The consultant will participate in a maximum of three meetings with the City of Renton and the Boeing Company's representatives/project consultants. The first meeting will be to review the scope of work and the proposed project's stormwater management plan. The second meeting will be to discuss the results of flood plain analysis review. The third meeting will be optional and used if subsequent reviews are required. 2. Flood plain analysis review: a. Review and discuss the difference between the FEMA adopted regulatory flood plain elevations and the maximum simulated future water surface elevations as determined in the hydrologic and hydraulic analysis tasks of the City of Renton East Side Green River Watershed Plan. Perform a qualitative assessment of the proposed CSTC stormwater management plans and effects on the City's hydrological and hydraulic analysis of the East Side Green River Watershed. Under Phase 2 the future condition FEQ model would be revised to reflect the CSTC development. Austin,TX in Boston,MA■Columbus,NE■Denver,CO R W BECK Indianapolis,IN■Minneapolis,MN•Saaatrento,CA Nashville,TN■Orlando,Fl. AND ASSOCIATES Phoenix,AZ■Seattle,WA A Recycled Paper Product Scope of Work East Side Green River Watershed Plan CAG 90-033 Addendum #4 Page 2 b. Review and analyze the Boeing Company's Customer Service Training Center flood plain analysis to check for compliance with City codes applying to flood plain management (primarily the compensatory storage and zero-rise requirements) and FEMA regulations. The review must verify if the proposed stormwater management plan for the Boeing Company's Customer Service Training Center complies with the compensatory storage, zero rise in the flood plain and the following flood plain management requirements: Special Requirements 7, 8 and 9 of the KCSWDM. It is understood that Boeing will be using the FEMA base flood elevation of 16.4 and will not conduct any further floodplain/floodway analysis (section 4.3.8 KCSWDM) to determine or revise the established flood plain elevation. 3. Review Technical Memorandum: The consultant shall prepare a technical memorandum which documents the information reviewed, the standards by which the review was based upon, the method of analysis used to conduct the review and the results of the review. The consultant shall identify any portion(s) of the proposed Boeing Customer Service Training Center which is not in compliance with the City of Renton Storm and Surface Water Management Ordinance, related City of Renton Municipal Codes and FEMA requirements which apply to flood plain management. Discuss the effects that the proposed Boeing CSTC stormwater management plan would have on hydrological and hydraulic analysis completed as part of the City's ESGRW Plan. Authorization to proceed with work on this task shall be subject to a letter of Notice to Proceed from the City. Total Cost: Phase 1 $ 6,780 Phase 2 (optional) $ 4,418 Total $11,198 (MSG.043) Austin,TX■Boston,MA■Columbus,NE■Denver.CO R W BECK Indianapolis,IN■Minneapolis,MN■Sacramento,CA Nashville,TN■Orlando,FL AND ASSOCIATES Phoenix,AZ■Seattle,WA A Recycled Paper Product CITY OF RENTON EASTSIDE GREEN RIVER WATERSHED PLAN May 1,1992 CONTRACT AMENDMENT NUMBER 4 - TASK 10 - BOEING REVIEW Phase 1(with qualitative analysis of Boeing impacts on ESGWP modeling) R.W.BECK AND ASSOCIATES RWB RWB RWB Subconsultant RS MSG MW WP LB SEC total total (Includes 5%mark—up) TOTAL Task No. Description $103 $70 $54 $43 $69 $32 hours expenses cost LKA COS X Boeing flood plain plan analysis review 1. meetings(3 @ 5 hrs each) 15 5 20 $30 $1,356 $1,356 2. Flood Plain Analysis review 2a1. Review Boeing Materials 6 10 16 $962 $962 2a2. Discuss FEMA Versus ESGRWP results 8 8 $563 $563 2a3. Assess the proposed CSTC impacts on ESGRW Plan 1 6 7 $394 $394 2b1. Flood Plain Analysis Review 2 20 22 $1,221 $1,221 3.Review Technical Memorandum 2 2 12 6 2 24 $100 $1,418 $1,418 4. Invoicingr—ontact Admin.(2 months) 8 2 2 12 $100 $865 $865 total 2 42 53 6 2 4 109 $230 $6,780 $0 $6,780 Phase 2(Optional)(modifying future conditions FEQ model to reflect CSTC development) R.W.BECK AND ASSOCIATES RWB RWB RWB SU13CONSULTANT RS MSG MW WP LB SEC total total TOTAL Task No. Description $103 $70 $54 $43 $69 $32 hours expenses cost LKA COS 2a4. Modify Future condition FEQ model&results Modify model 1 6 7 $394 $625 $1,019 New connections to Springbrook 1 6 7 $394 $394 Distribute hydrographs 1 4 5 $286 $286 Distribute wetland storage 1 6 7 $394 $394 Model Runs(assume all storms) 2 14 16 150 $1,047 $1,047 Document changes to model in next report 4 4 2 10 $584 $584 Invoicing/Contact Admin.(1 months) 6 2 1 9 $100 $692 $692 total 0 16 40 2 2 1 61 $250 $3,793 $625 $4,418 CITY OF RENTON MEMORANDUM DATE: May 1, 1992 TO: Lenora Blauman FROM: Ron Straka SUBJECT: R. W. BECK REVIEW OF THE BOEING CSTC PROJECT FLOOD PLAIN ANALYSIS Attached is a copy of the proposed budget sheet for the flood plain analysis review of the Boeing Customer Service Center Training Center (CSTC) by R. W. Beck and Associates. The Utility recommends that the work be authorized. The Phase II work (Task 2a4) will only be authorizated if it is identified as being needed as a result of the initial review of the CSTC flood plain analysis. The review of the Boeing project flood plain analysis is needed to ensure that the project will comply with the City flood plain regulations and surface water management codes. The review will also ensure that the project will not change the results of the Surface Water Utility's East Side Green River Watershed (ESGRW) Plan hydrologic and hydraulic analysis. The work was approved by Council as part of our consultant contract (CAG-90-033) Amendment No. 4. The total cost of option No. 2 is $11,198 with the Phase I work costing $6,780. The authorization of this task was subject to all work being funded by the Boeing Company. The task scope of work will benefit Boeing in the future, since it will document the differences between the FEMA flood plain elevation and the simulated flood plain elevation as established by the ESGRW Plan hydrologic and hydraulic modeling. This will also ensure that the hydraulic models which are being utilized to analyze potential flood control alternatives is up-to-date and accurately reflects the current hydrology and hydraulics in the basin. Please authorize us to utilize the Boeing CSTC work order (W.O.#87290) to establish a P.O. for completion of all work associated with the task. There is a possibility that the Phase II work will not be required. This review is important to both the Boeing CSTC project surface water management plan approval and the ESGRW Plan. If you have any questions regarding this subject, please contact me at X-5547. D:92-329:R.JS:ps CC: Priscilla Pierce Attachment CITY OFRENT'ON No EASISIDE GREEN RIVER WATERSHED PLAN �— May 1,1992 CONTRACT AMENDMENT NUMBER 4 - TASK 10 -- BOEING REVIEW Phase 1(with qualitati%v analysis of Boeing impacts on ESG3VP modeling) R3V.BECK AND ASSOCIATES RWB RWB RWB Subcomultant RS MSG MW WP LB SEC total total (includes 5%mark—up) T10TAI co TaskTask No. Description $103 S70 $54 S43 $69 $32 hours expenses cost LKA COS rn , X Boeing flood plain plan analysis review ' 0 1. meetings(3 @ 5 hra each) 15 5 20 S30 $056 CV I Flood Plain Analysis review I 2al. Review Boeing Mate681.7 6 10 161 $%2 z 2a2. Discuss FEMA Versus ESGRIVP results 8 81 $563 SW x W. Assess the proposed CSTC impacts on ESGRW Plan 1 6 71 $394 S3% Q 2bl. Flood Plain Analysis Review 2 20 22 S1,221 S1,221 T I 3.Review Technical Memorandum 2 2 12 6 2 24 S100 S1,418 $1.411 4. Invoicing/Conlacl Admin.(2 months) 8 2 2 12 $1W $865 S86' i i tcNal 2 42 53 6 2 4 109 $230 56,780: $0 S6,79( t_:_t 2 Phase 2(Optional)(modifying future conditi(w FEO model to retlect CSTtC development) U O R.W.BECK AND ASSOCIATES R1VB. RWB RWB SUBCONSULTANT RS MSG MW \VP LB SEC total; total j TOTA Task No. Description S103 $70 $54 $43 S69 S32 hour expenses cost LKA COS x tv 2a4. Modify Future condition FEO model&results t�0 t Modify model 1 6 7 5394 $625 $1,111' New connections to Springbrook 1 6 7 S394 S39 Distribute hydroe aphs 1 4 5 S286, S28 Distribute wetland storage 1 6 7 S394. S_'W Model Runs(assume all storms) 2 14 16 150 $1,047; SUM Document changes to model in next report 4 4 2 10 S584; $58 lovoking/Contacl Admin.(I months) 6 2 1 9 t $100 S692 $69 total 0 16 40 2 2 1 611 $250 $3,793 S62S $4,41 LL- tY CV I Q �! �= CITY OF RENTON "LL Planning/Building/Public Works Department Earl Clymer, Mayor Lynn Guttmann,Administrator April 13, 1992 Mike Giseburt R. W. Beck and Associates, Inc. 2101 Fourth Avenue - STE 600 Seattle, WA 98121-2375 SUBJECT: CITY OF RENTON'S EAST SIDE GREEN RIVER WATERSHED PLAN CAG 90-033 ADDENDUM #4 TASK .X THE BOEING COMPANY'S CUSTOMER SERVICE CENTER TRAINING CENTER FLOOD PLAIN ANALYSIS REVIEW Dear Mike: Enclosed for your examination is a revised draft scope of work for the review of the Boeing Company's Customer Service Training Center (CSTC) flood plain analysis site. This work was authorized as part of the City of Renton's East Side Green River Watershed (ESGRW) Plan consultant contract CAG 90-033 Addendum No.4, Task X. The purpose of this task is to ensure that the proposed Boeing Customer Service Training Center stormwater management plan complies with City and other agencies flood plain management codes and standards. It is also the purpose of this task to account for the proposed Boeing CSTC stormwater management plan's information in the development of the City of Renton's ESGRW Plan. The scope of work has been revised to apply only to the review of the flood plain analysis information relating to the Boeing CSTC stormwater management plan. The review must verify if the proposed Boeing CSTC stormwater management plan complies with the City's and other agency's flood plain management codes and standards. The task includes a review and discussion of the differences between the FEMA adopted flood plain elevation and the maximum simulated future water surface elevation for the site as determined in the hydrologic and hydraulic analysis tasks of the City of Renton's ESGRW Plan. A discussion as to what effect that the proposed Boeing CSTC stormwater management plan would have on City's hydrologic and hydraulic analysis of the ESGRW is also included in the task. The work completed in this task will be documented in a technical memorandum. 200 Mill Avenue South - Renton, Washington 98055 Mike Biseburt R. W. Beck and Associates, Inc. Page 2 Please review the scope of work and develop a budget for the task for our consideration. Enclosed is the available flood plain analysis information completed for the Boeing CSTC for your review. Also enclosed are the City's codes which apply to flood plain management. The majority of review standards are contained in the 1990 King County Surface Water Management Design Manual. Formal notice to proceed with the scope of work is required prior to initiation of task following our review and approval of the task's budget. If you have any questions regarding this subject, please contact Ron Straka at (206) 277-5547. Very truly yours, i ands Pars ns, P. pervisor Stormwat Utility D:92-266:/PRJS:ps CC: Ron Straka, Stormwater Utility Lenora Blauman, Planning Section F SCOPE OF WORK EAST SIDE GREEN RIVER WATERSHED PLAN CAG 90-033 Addendum#4 TASK X: THE BOEING COMPANY'S CUSTOMER SERVICE TRAINING CENTER FLOOD PLAIN ANALYSIS REVIEW The consultant shall conduct the detailed engineering flood plain analysis review of the proposed Boeing Company's Customer Service Training Center (CSTC) stormwater management plan. The plan will be checked for compliance with the City of Renton Standards/Codes and Policies along with other applicable regulatory agency requirements which apply to flood plain management. The consultant will ensure coordination of the Boeing Company's development of the Longacres Customer Service Training Center site with the City of Renton's preparation of the East Side Green River Watershed Plan and the Black River Water Quality Management Plan. The consultant will review the pertinent flood plain analysis information and new data resulting from the review will be integrated into the East Side Green River Watershed Plan. The work shall include the following sub-tasks: 1 . Coordination Meetings: The consultant will participate in a maximum of three meetings with the City of Renton and the Boeing Company's representatives/ project consultants. The first meeting will to review the scope of work and the proposed projects stormwater management plan. The second meeting will be to discuss the results of flood plain analysis review. The third meeting will be optional and used if subsequent reviews are required. 2. Flood plain analysis review: A) Document and explain the difference between the FEMA adopted regulatory flood plain elevations and the maximum simulated future water surface elevations as determined in the hydrologic and hydraulic analysis tasks of the City of Renton East Side Green River Watershed Plan. Assess the proposed CSTC stormwater management plans and effects on the City's hydrological and hydraulic analysis of the East Side Green River Watershed. - r � Scope of Work East Side Green River Watershed Plan Page 2 B) Review and analyze the Boeing Company's Customer Service Training Center flood plain analysis to check for compliance with City code and other agency regulations. The review must verify if the proposed stormwater management plan for the Boeing Company's Customer Service Training Center complies with the compensatory storage, zero rise in the flood plain and other applicable flood plain management requirements. 3. Review Technical Memorandum: The consultant shall prepare a technical memorandum which documents the information reviewed, the standards by which the review was based upon, the method of analysis used to conduct the review and the results of the review. The consultant shall identify any portion(s) of the proposed Boeing Customer Service Training Center which is not in compliance with the City of Renton Storm and Surface Water Management Ordinance, related City of Renton Municipal Codes and other Agency requirements (FEMA, CORPS, WSDOE, WSDOF) which apply to flood plain management. Document the effects that the proposed Boeing CSTC stormwater management plan would have on hydrological and hydraulic analysis completed as part of the City's ESGRW Plan. Authorization to proceed with work on this task shall be subject to a letter of Notice to Proceed from the City. Total Cost: $???? D:92-266a:RJS:ps CONCURRENCE DATE AME I TIA DATE Bfz April 1992 Mike Giseburt R. W. Beck and Associates, Inc. 2101 Fourth Avenue - STE 600 Seattle, WA 98121-2375 SUBJECT: CITY OF RENTON'S EAST SIDE GREEN RIVER WATERSHED PLAN CAG 90-033 ADDENDUM #4 TASK X - THE BOEING COMPANY'S CUSTOMER SERVICE CENTER TRAINING CENTER FLOOD PLAIN ANALYSIS REVIEW Dear Mike: Enclosed for your examination is a revised draft scope of work for the review of the Boeing Company's Customer Service Training Center (CSTC) flood plain analysis site. This work was authorized as part of the City of Renton's East Side Green River Watershed (ESGRW) Plan consultant contract CAG 90-033 Addendum No.4, Task X. The purpose of this task is to ensure that the proposed Boeing Customer Service Training Center stormwater management plan complies with City and other agencies flood plain management codes and standards. It is also the purpose of this task to account for the proposed Boeing CSTC stormwater management plan's information in the development of the City of Renton's ESGRW Plan. The scope of work has been revised to apply only to the review of the flood plain analysis information relating to the Boeing CSTC stormwater management plan. The review must verify if the proposed Boeing CSTC stormwater management plan complies with the City's and other agency's flood plain management codes and standards. The task. includes a review and discussion of the differences between the FEMA adopted flood plain elevation and the maximum simulated future water surface elevation for the site as determined in the hydrologic and hydraulic analysis tasks of the City of Renton's ESGRW Plan. A discussion as to what effect that the proposed Boeing CSTC stormwater management plan would have on City's hydrologic and hydraulic analysis of the ESGRW is also included in the task. The work completed in this task will be documented in a technical memorandum. Mike Biseburt R.,W.'Beck and Associates, Inc. Wage 2 Please review the scope of work and develop a budget for the task for our consideration. Enclosed is the available flood plain analysis information completed for the Boeing CSTC for your review. Also enclosed are the City's codes which apply to flood plain management. The majority of review standards are contained in the 1990 King County Surface Water Management Design Manual. Formal notice to proceed with the scope of work is required prior to initiation of task following our review and approval of the task's budget. If you have any questions regarding this subject, please contact Ron Straka at (206) 277-5547. Very truly yours, Randall Parsons, P. E., Supervisor Stormwater Utility D:92-266:RP:RJS:ps CC: Ron Straka, Stormwater Utility Lenora Blauman, Planning Section R.W. BECK AND ASSOCIATES 2101 Fourth Avenue,Suite 600■Seattle,Washington 98121.2375■USA Telephone(206)441-7500■Fax(206)441-4964 Consulting,(206)441-4962 Engineering Telex 4990402 BECKSEA WW-1159-BA1-CA October 29, 1992 3008 Mr. Ron Straka, Engineering Supervisor Storm Water Utilit ` City of Renton 200 Mill Avenue South E I 0 i99?_ Renton, Washington 98055 CITY CF RE'ITJhI Dear Ron: Engines-ning (pep" Subject: BOEING CSTC - Floodplain Analysis Review Contract No. CAG-03390 Invoice No. 4 - August and September Enclosed herewith is our invoice in the amount of $286.35 and cost documentation for the months of August and September. Work during the months of August and September included the revising and finalizing the technical memorandum. If you should have any questions, please call our office. Very truly yours, R. W. BECK AND ASSOCIATES Michael S. Vise6urt Project Manager MSG/rhm Enclosure (MSG.064) Boston,MA■Columbus,NE■Denver,CO■Indianapolis,IN■Minneapolis,MN Nashville,TN■Orlando,FL■Phoenix,AZ■Sacramento,CA■Seattle,WA 6-'16 A 71 T cled Paper Prosdmt z �- 3 o z � L w � rs O O w � �~ ! a `J 0 CR ice. Q Uw LL Cc COCIO W U °o Z w U w U H c� U a.� 0 r rr r r r r r r r r r r r r r■ rr rr s r R.W. BECK AND ASSOCIATES 2101 Fourth AN enue,Suite 600■Seattle,Washington 98121-2375■USA Telephone(206)441-7500■Fax(206)441-4964 Consulting,(206)441.4962 Engineering Telex 4990402 BECKSEA ' WW-1159-BAl-CA September 11, 1992 3023 Mr. Ron Straka, Project Manager Surface Water Utility Engineering Supervisor Utility Systems Division City of Renton 200 Mill Avenue South Renton, WA 98055 ' Dear Ron: ' Subject: City of Renton Boeing CSTC Floodplain Analysis Review We are pleased to submit this final technical memorandum for your review. The Boeing CSTC proposed stormwater controls meet the FEMA and City requirements, with one minor exception. This exception relates to the delineation of the FEMA floodway on the site improvement plans and is discussed in Section III. ' This memorandum also describes the differences between the Springbrook Creek FEMA floodplain elevations versus the flood elevations predicted under the East Side Green River Watershed Plan. If you have any questions, please contact me at 727-4607. Very Truly Yours, ' R. W. BECK AND ASSOCIATES f Mike Gi eburt ' Project Manager Boston,MA■Columbus,NE■Denver,CO■Indianapolis,IN■Minneapolis,MN \ashvill,,T\0 Orlando,FL■Phoenix,AZ■Sacrament,),CA■Seattle,XVA ' CERTIFICATE OF ENGINEER ' CITY OF RENTON BOEING CSTC FLOODPLAIN ANALYSIS REVIEW ' The technical material and data contained in this report were prepared under the supervision and direction of the undersigned, whose seal as a registered professional engineer ' licensed to practice as such in the State of Washington is affixed below. 24055 G�� rj.CIRF�Vcam' EXPIRES: /Z' 0, - !Z Michael Gisebur TABLE OF CONTENTS Section Page ' Number Title Number ' Letter of Transmittal Certificate of Engineer ' Table of Contents I. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ' A. Purpose, Authority and Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 B. Overview of Proposed CSTC Facility . . . . . . . . . . . . . . . . . . . . . . . . . . I II. FEMA FLOODPLAIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 ' A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 B. FEMA Floodplain 2 C. ESGRW Plan Hydrologic/Hydraulic Analysis . . . . . . . . . . . . . . . . . . . . . 3 ' D. Differences between FEMA and ESGRW Plan . . . . . . . . . . . . . . . . . . . . 4 E. Conclusions 7 III. CSTC FLOODPLAIN ANALYSIS REVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 A. Information Reviewed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 ' B. Floodplain Analysis Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 C. CSTC Effects on ESGRW Plan Computer Model 15 D. Miscellaneous Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 E. Conclusions/Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 ' List of Tables Table I Comparison of Peak Flows and Water Surface Elevations - ' FEQ Computer Model and FEMA Table 2 Comparison of Compensatory Storage Volumes 1159WWO.588 1 09/11/92 I. INTRODUCTION A. Purpose, Authority and Scope 1 The Boeing Company has submitted a permit application to develop the Customer Services Training Center (CSTC) located in the north portion of the existing Longacres race ' track. The purpose of this investigation is to review the proposed CSTC facility for compliance with FEMA and City of Renton standards for development in the floodplain. A second purpose is to describe the differences between the Springbrook Creek FEMA floodplain elevations versus the flood elevations predicted under the East Side Green River Watershed (ESGRW) Plan and to assess impacts from the proposed CSTC stormwater facilities on the ESGRW Plan ' hydrologic/hydraulic modeling results. This work was authorized by the City of Renton by virtue of an engineering agreement with R. W. Beck and Associates and a notice to proceed dated April 13, 1992. B. Overview of Proposed CSTC Facility ' The Boeing CSTC facility consists of an approximately 76-acre office development located in the northerly portion of the Longacres race track. The proposed CSTC surface water controls are described in the Technical Information Report (TIR) on the Floodplain/Storm Water System, prepared by Sverdrup, April 1992. ' Springbrook Creek forms the east border of the site. Nearly the entire CSTC site is within the Springbrook Creek floodplain as defined by FEMA (TIR Figure 8). A series of large ponds located in the southern portion of the CSTC site are proposed to provide compensatory ' floodplain storage, water quantity control, and water quality control (TIR Figure 7) prior to discharging into Springbrook Creek. Springbrook Creek is the dominate stream system of the 24 square mile ESGRW. Springbrook Creek flows in a northerly direction through the Renton valley to the Black River Pump Station (BRPS) where flows are pumped to an outlet channel draining to the Green River. ' Pumped discharges from the BRPS are restricted under the terms of the Green River Management Agreement (GRMA) which requires the pump station to restrict pumping rates during high Green River flows. 1 I"W W o*... 1 09/11/92 S II. FEMA FLOODPLAIN A. General The purpose of this section is to provide background information on the FEMA flood- plain and to document differences between the FEMA adopted regulatory floodplain elevations and the simulated water surface elevations as determined under the ESGRW planning effort. B. FEMA Floodplain The most recent FEMA study of Springbrook Creek was completed in 1989. This study was a compilation of previous work by FEMA completed by Tudor Engineering in 1979 supplemented with a recent detailed study revision of lower Springbrook Creek by CH2M Hill in 1989. The recent study revision included updated base flood maps for Springbrook Creek between the BRPS and SW 16th Avenue. The hydrologic analysis for the FEMA study included the development of a TR-20 computer model. Predicted base flood peak rates are shown in the ' right-hand column of Table 1. ' The methodology for the hydraulic analysis of the Springbrook system was one of the most important factors in the floodplain results. A discussion of FEMA's hydraulic methodology to determine the starting water surface elevations at the BRPS is provided below. ' "The maximum water-surface elevation of the P1 (BRPS) storage pond in Renton was determined by routing the hydrograph through the storage pond and pumping station by ' using the storage-elevation relationship for the pond and the pumping station's firm capacity of 875 cfs as the maximum discharge. The 10-year water-surface profile for Springbrook Creek was started at normal depth because the normal depth was greater than 3.5 feet NGVD, which is the maximum water-surface elevation of the Pl storage pond under standard operating procedures. The peak 10-year flow into the storage pond is less than the maximum pumping rate and, therefore, no rise in the water-surface elevation of the storage pond should occur during the 10-year event. Two conditions were considered for each of the 50- and 100-year events. The first consisted of modeling the effects on the Springbrook Creek study reach of the computed maximum water-surface elevation that may be reached in the storage pond (the starting water surface elevation) coincident with the flow that would be discharged from Springbrook Creek at that time step in the inflow runoff hydrograph. The second condition of analysis consisted of modeling the effects of Springbrook Creek peak inflows for the recurrence interval event under consideration, with a starting water-surface elevation of the higher of the normal depth, or the coincident elevation of the storage pond at the time of the peak inflow. For each recurrence interval, ' the higher water-surface elevation resulting from each of those analysis conditions at the study reach cross sections was used for final flood profile determination."' ' Federal Emergency Management Agency. 1989. Flood Insurance Study, King County, Washington, Federal Emergency Management Agency. 1159WWO.588 2 09/11/92 Table 1 Comparison of Peak Flows and Water Surface Elevation FEQ Computer Model and FEMA FEQ(Current 100 yr.storage) FEQ(Current 100 yr.cony.) FEQ(future 100 yr.storage) FEQ(future 100 yr.cony.) FEMA(1) Roadway Existing Channel System Existing Channel System Existing Channel System Existing Channel System Top Elev. Flow Elevation Flow Elevation Flow Elevation Flow Elevation Flow Elev. Location/Discription (cfs) (cfs) (cfs) (cfs) (cfs) BRPS outflow 925 903 1439 1439 BRPS inflow 588 8.10 903 4.95 950 12.95 1105 8.10 1230(2) 15 Grady Way u/s 502 AM 947 9.44 831 13.01 1007 9.99 1100 16 SW 16th u/s 501 8.84 846 9.91 804 13.04 1005 10.52 16 Confluence of North 60"SS 499 9.63 844 11.31 792 13.16 1003 11.97 16 Confluence of P-9 461 10.38 767 12.12 680 13.28 925 12.81 16 SW 27th u/s 17.9 457 11.29 780 14.31 656 14.25 934 15.85 16.3 SW 34th u/s 14.9 501 12.31 941 15.45 765 15.04 1097 16.15 16.8 Oaksdale d/s 17.1 477 13.32 874 16.43 720 15.74 1025 17.09 17.7 Oaksdale u/s 477 13.90 874 17.60 720 17.16 1025 17.93 17.7 SW 43rd d/s 22.9 477 14.33 867 17.89 728 17.39 1017 18.28 18 SW 43rd u/s 22.9 477 14.46 867 18.40 728 17.68 1017 19.01 18 Notes (1)FEMA is based upon current land use conditions and does not consider future land use conditions. Elevations are approximated from FEMA maps. (2)1230 cfs is the peak flow. However,the flow corresponding to the flood plain elevation is 785 cfs which corresponds to a starting water surface in the forebay of elevation 15.0 For the 100-year event, the first condition discussed above, associated with the maximum water surface elevation in the BRPS forebay, was found to give the highest water surface profile for Springbrook Creek through the Renton valley. This corresponded to maximum water surface in the forebay of 15.0 and a Springbrook Creek flow rate of 785 cfs. Using this methodology a water surface profile of 16.4 was determined upstream of SW 16th Street. This elevation was used for determining floodplain limits within the CSTC site. A major assumption of the FEMA analysis was that high Green River flows and high Springbrook Creek flows reflect a non-coincident type of event. That is, high Springbrook Creek flows are presumed to occur without high Green River flows. For the floodplain analysis, it was assumed that there would be no BRPS pumping restrictions during the Springbrook Creek flood event. Based upon discussions with the FEMA contractor, this assumption was made in part because, the BRPS had never limited pumping due to high Green River flows 4 C. ESGRW Plan Hydrologic/Hydraulic Analysis The detailed methodology for the hydrologic and hydraulic analyses conducted as a part of the ESGRW Plan is contained in the ESGRW Plan Hydrologic Analysis Report' and the ESGRW Plan Hydraulic Analysis Report - Existing Drainage System.' A brief summary of the analysis is provided in the following paragraphs. As part of the ESGRW Plan, both hydrologic and hydraulic computer models were developed to simulate Springbrook Creek's response to rainfall. The hydrologic computer modeling was performed using EPA's 1988 version of the Hydrologic Simulation Program Fortran (HSPF). HSPF is a sophisticated computer modeling program that simulates land surface and in-stream hydrologic processes on a continuous basis. The hydraulic computer modeling was done using the FEQ (Full Equations) computer model. The FEQ is a non-steady state hydraulic model that routes inflow hydrographs through open channels or closed conduits,computing water surface elevations and flows. The HSPF model was used to generate runoff hydrographs for Springbrook Creek and major tributaries. FEQ then routes these hydrographs through the drainage system until flows are pumped into the Green River by the BRPS. The current and future conditions modeled using HSPF/FEQ, and the FEMA peak flow rates and water surface elevations are shown in Table 1 and shown in profile in the Appendix (Figure 4 from the ESGRW Plan Hydraulic Analysis Report - Existing Drainage System). The HSPF/FEQ analysis found that, in order to determine the adequacy of Springbrook Creek to convey and store peak flows, two different flood simulations were necessary to ' Personal Communication. Shelley Sundgren, Engineer, CH2M Hill. June 24, 1992. 2 Northwest Hydraulic Consultants. December 1991. Eastside Green River Watershed Hydrologic Analysis. R. W. Beck and Associates and the City of Renton. ' R. W. Beck and Associates. March 1992. Eastside Green River Watershed Plan Hydraulic Analysis, Existing Drainage System. City of Renton. 1159WWO.588 3 09/11/92 determine the 100-year frequency flood (base flood). One of the flood simulations was needed to ensure that Springbrook Creek will have sufficient capacity to convey peak flows to the BRPS. This flood simulation reflects severe local storm conditions without coincident high Green River flows which would require pumping restrictions per the GRMA. The second flood simulation was performed to ensure that Springbrook Creek and the BRPS Forebay have sufficient storage capacity (during periods of high Green River flow and consequent BRPS pumping rate restrictions) to temporarily hold flood waters without causing flooding damage to structures or roadways. ' D. Differences between FEMA and ESGRW Plan There are several reasons for the wide variance between the FEMA results and the ESGRW Plan results. These differences are categorized into three groups as follows; methodology, changes in the drainage system infrastructure, and topographic information. 1. Methodology a. HSPF versus TR20 (continuous versus event modeling). HSPF is a continuous hydrologic simulation model which uses physically-based soil moisture accounting algorithms to transform long time series of observed rainfall data into corresponding continuous sequences of runoff. Use of a long record of rainfall data (26 years for the ESGRW Plan) allows consideration of the wide range of meteorological conditions that have ' actually occurred in the past. Other single storm event-type models, such as the SCS TR-20 or HEC-1 models, in contrast, commonly use a small number of hypothetical "design" storm events, which are not necessarily irepresentative of local conditions in terms of either the duration and distribution of rainfall or soil moisture conditions prior to the "design" event. Continuous hydrologic modeling is of particular value in studying a hydrologic system such as the ESGRW because it allows detailed examination of the interrelationships between flows in the Green River and local runoff from the ESGRW. As noted earlier, maximum allowable pumped discharges from the ESGRW into the Green River via BRPS are constrained by the terms of the GRMA. Allowable pumped discharges are reduced progressively from approximately 3,000 cfs to 0 cfs as flows in the Green River at Auburn increase from 9,500 cfs to 12,000 cfs. The joint occurrence of high flows on the Green River and high flows in the ESGRW system is, therefore, of critical interest in determining the amount of flood control storage required in the ESGRW system. The ESGRW Plan results indicate that during the 26-year period of record, there was only one significant event in which high Green River flows required significant curtailment of the BRPS pumping rates (1975). During this period, the ESGRW area was experiencing the equivalent of approximately a 2-year event. Alternatively, during the most significant 1159WWO.588 4 09/11/92 i floods on the ESGRW system, the Green River flows were not significant. From these results, it can be concluded that extreme events on each of these systems can occur independently. The FEMA study considers high Green River flows and high Springbrook Creek flows to reflect a non-coincident type of event. However, the ESGRW Plan study indicates that high Green River flows can result in high Springbrook Creek water surface elevations. Furthermore, the simulated 100-year flood event (with high Green River flows) was predicted to have the highest Springbrook Creek water surface elevations for future conditions between the BRPS and SW 27th Street. It should ' also be pointed out that, because of the relatively short record available, and that there was only one event in the 26-year period of record that the Green River significantly constrained the BRPS operation, there is uncertainty in the estimation of Springbrook Creek water surface elevations. It is difficult to predict how the difference of the two modeling approaches affect the results. The HSPF model predicts lower peak flow rates, however it is believed that the HSPF also predicts higher runoff volumes. The HSPF modeling approach is generally considered to be more reliable due to the reasons mentioned above. It should be noted, however, that more recent hydrologic work completed by Northwest Hydraulic Consultants (NHC) for the City of Kent on the Mill Creek basin indicates that the ESGRW Plan hydrology may be underestimating peak flow rates. The 100-year flood predicted by the HSPF model for the ESGRW was based upon a study period of 1961-1987. By expanding the study period to include the severe flood events of 1990 and 1991, the HSPF model will likely predict higher peak flows as much as 20% higher than previously predicted. b. FEQ Versus HEC-2 (non-steady versus steady state modeling). FEQ (Full Equations), a sophisticated non-steady state flow hydraulic routing model, was selected over previously used steady state models such as HEC2 and WSP2 because it can simulate the complex hydraulics of the Renton Valley drainage system. Therefore, it more accurately reflects the ability of the drainage system to convey and to store water. FEQ performs a one-dimensional analysis of flow hydraulics using the St. Venant equations. As a non-steady state model, FEQ can simulate the storage in the system during the passage of a flood wave. As a result, the non-steady state modeling approach tends to attenuate peak flows during the passage of a flood wave. This contributes to the ESGRW Plan findings predicting lower water surface elevations than the FEMA work. C. Detailed Modeling of the Major Valley Wetlands. The FEQ model was set up to model the interaction between major valley wetlands and Springbrook Creek. The valley wetlands were defined in FEQ by area- 1159WWO*... 5 09/11/92 elevation curves and hydraulic connections to the system. An area- elevation curve consists of a relationship between surface area and elevation. FEQ internally computes the storage volume contained within the wetland at any given elevation based upon the area-elevation curves. A defined hydraulic connection between the wetlands and the drainage system is used to simulate wetland inflows and outflows from Springbrook Creek. We presume that the detailed modeling of the valley area wetlands adds a tremendous amount of flood storage to the system that was not directly accounted for in the FEMA work (Note 1). For example, FEQ wetland numbers 6 and 7, illustrated on Figure 3 in the Appendix, provide approximately 308 acre-ft of off-channel storage at elevation 15. This off- channel storage helps to attenuate peak flood flows. For the 100-year 1 current condition flood, the peak simulated flow rates are reduced from 941 cfs to 780 cfs as a result of this off-channel storage. The detailed modeling of the major valley wetlands contributes to the ESGRW Plan findings predicting a lower water surface profile than the FEMA work. 2. Changes in the Drainage System Infrastructure ' Since the time of the FEMA study, several drainage system infrastructure changes have occurred. These changes, listed below, affect the conveyance capacity of the system and consequently the predicted floodplain elevations. a. Improvements to the BRPS capacity. Since the time of the FEMA study, two of the larger, 514 capacity pumps have been brought on-line. As a result, the pump station nominal capacity was increased from 875 cfs (used in the FEMA study) to approximately 1917 cfs. This is a significant change to the FEMA analysis because the peak flow of Springbrook Creek no longer exceeds the pump capacity. Had these improvements been in place for the FEMA study, the starting water surface elevation in the forebay would have been the normal depth at the peak flow rate rather than elevation 15. The ESGRW Plan study reflects the higher pump station capacity. This infrastructure change contributes to the ESGRW Plan findings predicting a lower water surface profile than the FEMA work. Note 1: The FEMA cross sections south of SW 16th Street were developed during the 1979 study and are not readily available for review. Review of these cross sections would provide some information on the extent to which wetlands adjacent to Springbrook Creek were accounted for in the FEMA/HEC-2 model. 1159wwo"" 6 09/11/92 b. Grady Way box culvert. The Grady Way Box Culvert consists of 5 cells with one cell having an invert elevation approximately 2 feet lower than the other cells (for a low flow channel). During the time of the FEMA study, wooden piles blocked off four of the five cells leaving only the low flow cell to pass flow. In 1991, the wooden piles blocking two of the cells were removed. This change reduces the head loss through the box culvert, and contributes to the ESGRW Plan findings predicting a lower water surface profile than the FEMA work. C. SW 16th Street Bridge. The SW 16th Street Bridge was removed and replaced with a wider span bridge since the FEMA work was completed. ' The new bridge has a clear span of approximately 60 feet compared to the old bridge span of approximately 36 feet with piers located within the floodway. This infrastructure change reduces the head loss through the bridge crossing and contributes to the ESGRW Plan findings predicting a lower water surface profile than the FEMA work. 3. Topographic Information There is an apparent discrepancy in the bottom elevation profile in the FEMA study information versus recent surveys by NHC. Figure 3 in the Appendix illustrates the FEMA bottom profile versus more recent survey findings. The discrepancy includes the SW Grady Way box culvert information. The FEMA bottom profile is in some cases almost 3 feet higher than the recent survey information. Using the recent survey findings results in a lower water surface profile of Springbrook Creek. Based on a telephone conversation with the FEMA contractor, the elevations used in the FEMA analysis were determined from a combination of existing channel geometry (based on survey) and proposed future channel geometry based upon the SCS design drawings for the P-1 Channel and the SW Grady Way box culvert which was under construction.4 The recent survey information is considered to be more accurate because some of the FEMA elevations were based upon the channel geometry existing prior to construction of the P-1 channel. Using the recent survey findings results in lower predicted Springbrook Creek water surface elevations than the FEMA work. E. Conclusions While several factors contribute to the ESGRW Plan predicting lower water surface elevations than prior FEMA work, the primary reason is believed to be the increased capacity at the BRPS. Considering this change alone would result in a significantly lower water surface profile through the lower reaches of Springbrook Creek. a Personal Communication. Shelley Sundgren, Engineer, CH2M Hill. June 24, 1992. 1159WWO.588 7 09/11/92 The ESGRW Plan effort has examined the Springbrook system with considerably more detail than that of the FEMA study using a sophisticated approach and taking into account infrastructure changes in the drainage system. Consequently, the ESGRW Plan analysis is considered to be more reliable. As previously mentioned, it should be noted that the HSPF work was based on a study period of 1961-1987 and did not include the severe events in 1990 and 1991. Adding the rainfall data for 1988-1991 to the HSPF simulation could increase the predicted flow rates as much as 20%. This could result in a higher water surface profile than previously predicted. It should also be noted that, because of the relatively short 26-year record available, and because there was only one event in the period of record where Green River flows significantly ' constrained the BRPS operation, there is uncertainty in the estimation of Springbrook Creek water surface elevations coincident with high Green River flows. 1 Preparing a FEMA letter of map revision to lower the regulated floodplain elevation to the results of the ESGRW Plan offers significant advantages, primarily, reducing the quantity of fill material required for future building development. The City should consider the following items when deciding whether or not to pursue a FEMA letter of map revision. • The HSPF/FEQ models should be updated to incorporate the recent severe floods of 1990 and 1991 prior to a FEMA letter of map revision request because the higher predicted flows will result in a higher floodplain elevation. The models should be updated for both the existing channel system and for preliminary ESGRW Plan flood control alternatives. It is important to consider the flood control alternatives because they result in higher water surface elevations in the lower reaches of Springbrook Creek than the existing channel system. • The City will need to select new flood elevations based upon either existing or future land use condition hydrology. The hydrology for determining the FEMA floodplain is usually based upon land use conditions at the time of the FEMA study. However, for the City of Renton, it is recommended that future hydrologic conditions be used in any floodplain analysis because of the significant increase in projected flows and corresponding floodplain elevations under future conditions. • It is important to note that the future condition HSPF model assumes that the Kent regional detention and enhanced wetland facility (Kent Lagoons) is operational. This proposed facility is planned to provide significant flood flow attenuation. If it is not constructed, higher Springbrook Creek floodplain elevations than predicted under the ESGRW Plan will result. Therefore, it is recommended that the Kent Lagoons project be operational prior to requesting a FEMA letter of map revision. Otherwise, the ESGRW Plan hydrology and hydraulic models should be revised and evaluated considering that the Kent Lagoons facility is not operational. 1159wR10.588 8 09/11/92 i III. CSTC FLOODPLAIN ANALYSIS REVIEW A. Information Reviewed The information reviewed as a part of the floodplain analysis review included the following: • Technical Information Report on the Floodplain/Stormwater System for the Customer Services Training Center (CSTC) Site Development, by Sverdrup, April 1992. (Three volumes) • 1" = 100' scale topographic mapping of pre-development and proposed post- development site conditions, by Sverdrup, January 1992. B. Flood lain Analysis Review P y The following paragraphs describe FEMA and City requirements for development in the floodplain and the corresponding analysis of the CSTC proposed stormwater improvement plans to comply with these requirements. 1. FEMA ' Requirements. The FEMA regulations primarily pertain to development in the floodway as opposed to development in the flood fringe. The floodway is delineated for the purpose of keeping an area clear of obstruction to allow flood waters to freely discharge downstream. The flood fringe is that portion of the plain outside the floodway which is covered by flood waters during the base flood. Under FEMA regulations, development in the flood fringe is permitted provided it complies with applicable elevation or flood proofing requirements. Non-residential structures must be flood proofed to or above the base flood elevation.5 Analysis. It appears from a review of the CSTC site plan, development activities (filling) is only proposed within the flood fringe and does not impact the floodway. However, the location of the floodway is not shown on the site improvement plan as required by KCSWDM Special Requirement 9 (discussed below). The floodway should be delineated on the site improvement plans to confirm that no filling is proposed in the floodway. In terms of flood proofing, the TIR indicates that all proposed building floor slabs will be located a minimum of two feet above the FEMA floodplain elevation of 16.4. 5 Hydrologic Engineering Center, Water Resources Support Center, U.S. Army Corps of Engineers. May 1990. Procedures for Compliance with Floodway Regulations. Federal Emergency Management Agency. 1159W o"" 9 09/11/92 This satisfies the FEMA requirement that non-residential structures must be flood proofed to or above base flood elevation. Therefore, the CSTC satisfies FEMA requirements, provided that no filling is proposed in the floodway. 2. City of Renton The City of Renton has adopted portions of the 1990 King County Surface Water Design Manual (KCSWDM) which set forth the primary stormwater management requirements for development in the floodplain. In addition to the KCSWDM, the City's draft Comprehensive Plan, Shoreline Management Plan, and Flood Hazards Code contain additional requirements for development in the floodplain. These codes focus on land use planning issues while the focus of this review effort was to verify that the CSTC facility satisfies the engineering and technical requirements (as opposed to planning) which are contained in the KCSWDM. The KCSWDM requirements are discussed below. a. Compensatory Storage. Requirements. The CSTC Development is required to provide compensatory storage. Compensatory storage is defined in the KCSWDM as "new excavated storage volume equivalent to the flood storage capacity eliminated by filling or grading within the flood fringe. Equivalent shall mean that the storage removed shall be replaced by equal volume between corresponding one foot contour intervals that are hydraulically connected to the floodway through their entire depth."' h Analysis. The compensatory storage requirement was reviewed with respect to two different viewpoints and are discussed in the following paragraphs. The first viewpoint considers the pre- and post-development flood storage up to the FEMA elevation of 16.4. The second viewpoint considers only the effective flood storage based upon the Springbrook 100- year base flood elevations as determined under the ESGRW Plan. b. Compensatory Storage per FEMA Elevation. The TIR's storage volume calculations for the site were checked for both pre-development and post-development conditions. Topographic maps provided by Sverdrup were used to calculate surface area at two foot contour intervals. The storage volumes were then calculated using the end-area method. The resulting storage volumes were compared with those given in the TIR, for both cumulative storage volume and 6 King County Department of Public Works, Surface Water Management Division. January 1990. King County, Washington Surface Water Design Manual, King County Department of Public Works, Surface Water Management Division. 1159WWO.588 10 09/11/92 incremental storage volume. The results are presented in Table 2. Cumulative storage volume was considered as the total storage volume between the outlet elevation and the FEMA elevation of 16.4, whereas the incremental storage volume was considered as the storage volume between one foot contour intervals. In terms of cumulative storage volume, our results do not match exactly with that of the TIR, but the comparison shows that the post development cumulative volume exceeds the pre-development volume. In terms of the incremental storage volume, the post-development storage ponds have more incremental storage than the pre-development site with the exception of elevations 15 to 16, and from 16 to 16.4. While this appears to be contrary to the definition of compensatory storage, we do not believe this to be an issue. This is because the ESGRW Plan hydrologic/hydraulic modeling results indicate that the Springbrook Creek floodplain elevation at the CSTC site is substantially lower than 16.4. (Approximately elevation 11 for current conditions and elevation 12 for future conditions.) Therefore, flood storage above these elevations is ineffective and does not attenuate flood flows. In addition, this should not be an issue, as there is substantially more cumulative post-development storage volume below ielevation 15. Therefore, when considering compensatory storage per FEMA elevations, the TIR satisfies the compensatory storage requirement. C. Compensatory Storage Considering the ESGRW Plan Results. As previously discussed, the hydrologic/hydraulic computer modeling completed as a part of the ESGRW Plan found substantially lower 100- year Springbrook Creek water surface elevations (11 for current land use conditions) than FEMA. When considering the ESGRW Plan results, the pre-developed CSTC does not store any flood flows from Springbrook, but rather, the site only stores the runoff generated from on-site which is temporarily held back due to the characteristic of the outlet control and any backwater influence from Springbrook Creek. This is due to the existing flap gate which prevents Springbrook Creek flow from entering the site. The actual determination of the effective storage volume provided by the site is complex. This is because the elevation of Springbrook Creek can influence outflows from the Site. During a storm event, runoff generated on-site discharges to Springbrook Creek freely until Springbrook Creek rises above the discharge elevation. As Springbrook Creek continues to rise above the discharge elevation, outflows are restricted and the site begins to store water. When Springbrook Creek is above the discharge elevation, outflows are determined by the head differential between the site and Springbrook Creek (and also influenced by the outlet control configuration). The effective flood storage provided by the site is the 1159WWO.588 11 09/11/92 t TABLE 2 — COMPARISON OF COMPENSATORY STORAGE VOLUMES Cumulative Storage Volume (ac—ft) Pre—development Post—development Elevation TIR(1) RWB TIR (1) RWB 8.5 0 0 0 0 9 0 0 4 3 10 0.2 0 13 12 (3) 11 1 4.5 25 24 12 7 9 39 38 13 18 23 55 56 14 32 37 74 76 15 49.5 65.5 94 101 16 74.5 94 115 130 16.4 89 109 (2) 125 (2) 143 (2) Incremental Storage Volume (ac—ft) Pre—develo ment Post—de velo ment Elevation TIR(1) RWB TIR(1) RWB r8.5 0 0 0 0 9 0 0 4 3 10 0 0 9 10 (3) 11 2 2 12 11 12 5 6 14 15 13 11 Il 16 18 14 14 17 19 21 15 17 24 20 24 16 26 32 21 (4) 29 (4) 16.4 13 15 10 (4) 13 (4) Notes (1)Source:TIR Figure 25. (2)Extrapolated above elevation 16 (3)It was assumed that storage below elevation 10 was ineffective due to high ground water table. (4)Post—development incremental storage is lower than pre— development incremental storage (5)RWB data based upon Y=100'topographic map by Sverdrup dated 1/9/92 for elevations 10, 12, 14,and 16. Data for elevations 11, 13,15,and 16.4 is based upon averaging. volume of on-site storage during the time of the peak water surface elevation in Springbrook Creek. This type of situation cannot truly be analyzed using steady state hydraulics. This is because Springbrook Creek elevations are constantly changing and affecting the rate of outflow from the site. This type of situation can be analyzed using non-steady state modeling such as done for the ESGRW Plan, however, non-steady state modeling has rarely been required of analysis for development proposals such as the CSTC because it is costly, sophisticated, and, until recently, could not be performed using microcomputers. Instead, this type of situation is usually analyzed using steady state hydraulics and making some simplifying assumptions (as done in the TIR). For example, the TIR predicted the peak outflows from the site using two different methods. First, it was assumed that Springbrook Creek did not influence the site outflows at all. The second method assumed that Springbrook Creek was sufficiently high to prevent any outflows at all until flows overtop the existing CSTC sill at elevation 15. In both cases, the TIR estimated that the post-development peak flows are lower than the pre-development peak flow rates. Therefore, the TIR considered the two extreme cases of influence by Springbrook Creek. In both cases the TIR shows a reduction in peak flows and consequently more on-site storage. In actuality, the influence of Springbrook Creek will lie somewhere between these extremes. Consequently, because the TIR shows a reduction of peak outflows at these two extremes, it is logical to presume that it would also show a reduction in peak outflows when Springbrook Creek is somewhere between these two extremes. Using the qualitative analysis approach, we believe that the post-development CSTC provides more effective storage than the pre-developed site, and therefore satisfies the City's criteria for compensatory storage. d. Special Requirement No. 7 - Closed Depressions. Requirements. A copy of Special Requirement No. 7 is included in the Appendix. Closed depressions are low-lying areas which have no, or such a limited, surface outlet that in most storm events, the area acts as a retention basin, holding water for infiltration into the ground or evaporation into the air. The TIR considered the CSTC site as a closed depression because Springbrook Creek can be high enough (per FEMA) to prevent outflows from the CSTC site. Closed depression sites must meet the following: When a closed depression is contained solely on a project site, the volume of rainfall previously contained by the closed depression must be retained in dead storage on-site; and, 1159WWO.588 12 09/11/92 • The volume of runoff from the project to any off-site closed depression must not increase,except as allowed under the condition of special Requirement number 8, Use of lakes, wetlands or closed depressions for peak rate runoff control. For closed depressions, Special Requirement number 7 also requires the analysis of the downstream impacts from the 2-, 10-, and 100-year, 24- hour duration, and the 100-year seven day duration design storm events. Analysis. The TIR considers the CSTC facility as a closed depression because high Springbrook Creek elevations (per FEMA 100-year base flood elevation of 16.4) can prevent outflows from the site. When considering that the maximum water surface elevation of Springbrook Creek is only approximately 11 per the ESGRW Plan results, the CSTC facility could be considered as having only a restricted outlet instead of an outlet which can prevent outflows. Consequently, the City may wish to review the applicability of this requirement. Nevertheless, because the adopted FEMA 100-year base flood elevation is the regulatory requirement, the closed depression analysis was performed. In any case, the CSTC facility satisfies the criteria required in the closed depression analysis. The first requirement states that when a closed depression is contained solely on a project site, the volume of rainfall previously contained by the closed depression must be retained in dead storage on-site. This criteria is met because there is no pre-development storage volume which is solely contained on the site. Under pre- development conditions, stormwater is temporarily stored on-site during a flood but is allowed to drain freely once Springbrook Creek recedes. The second criteria states that the volume of runoff from the project to any off-site closed depression must not increase, except as allowed under the conditions of special requirement number 8. The CSTC site discharges to Springbrook Creek which is generally not a closed depression, therefore, this criteria is also met. It should be noted that although Springbrook Creek does have a restricted outlet (due to the GRMA), such restrictions have occurred so infrequently that it should not be considered a closed depression. Alternatively, if Springbrook Creek were considered a closed depression, the CSTC would still satisfy this criteria. This is because the TIR predicted a post- development condition increase in runoff volume of 1.3 and 2.1 acre-ft for the 100-year 24-hour event and the 100-year 7-day event respectively. At the same time, the proposed storage facilities provide approximately 20 acre-feet of storage over pre-developed conditions (at elevation 12). The TIR included the analysis of impacts to the downstream system (i.e., the 2-, 10-, and 100-year, 24-hour duration, and the 100-year seven day 1159WWO.588 13 09/14/92 event). In all cases but one, the post-development peak flow rates discharging to Springbrook Creek were lower than pre-development rates. An error was discovered in the one case predicting a higher post development flow, and this simulation was re-computed and resulted in a lower post-development peak flow than pre-development. The storm event which originally showed an increase in the peak discharge rates after development was the 100-year 7-day storm with Springbrook Creek influence (The TIR modeled this event under two situations, no Springbrook Creek influence and with Springbrook Creek influence). The revised computations for this case are included in the Appendix and referenced as TIR amendment number 1. e. Special Requirement No. 8 - Use of Lakes, Wetlands or Closed Depressions for Peak Rate Runoff Control. Requirements. A copy of Special Requirement No. 8 is included in the Appendix. This requirement pertains to the use of the floodplain for runoff quantity control and states that the increased volume of runoff from the proposed project may not increase the 100-year floodplain elevation of a lake, wetland, or closed depression more than 0.1 feet unless several provisions are met. Analysis. The TIR (and amendment number 1) show that for all storm events modeled, the post-development peak runoff rates are lower than the pre-development peak runoff rates. Also, as mentioned under Special Requirement number 7, the increase in the post-development runoff volume, 1.3 and 2.1 acre-feet for the 100-year 24-hour event and the 100- year 7-day event, respectively, is offset by providing a significant increase in post-development flood storage volume. Therefore, there should be no increase in the Springbrook Creek flood elevations. f. Special Requirement No. 9 - Delineation of 100-Year Floodplain. Requirements. A copy of Special Requirement No. 9 is included in the Appendix. This requires the delineation of the 100-year floodplain boundaries (and floodway) on site improvement plans and profiles. Analysis. The TIR provides figure 8 to delineate the floodplain boundary. Neither detailed floodplain boundaries nor the floodway boundaries are illustrated on the other site plan drawings. The FEMA floodplain and floodway boundaries should be shown on site improvement plans to ensure that there is no proposed filling in the floodway. 1159WWO.588 14 09/11/92 1 C. CSTC Effects on ESGRW Plan Computer Model One objective of this investigation was to assess impacts from the proposed CSTC stormwater facilities on the East Side Green River Watershed (ESGRW) Plan hydrologic/hydraulic modeling results recently completed by the City of Renton. The ESGRW Plan model considered the entire Longacres race track as one subbasin (the location of subbasin S 11 is illustrated on Figure 3 taken from the ESGRW Plan' included in the Appendix) which was connected to Springbrook Creek in one location approximately 800 feet south of SW 19th Street. The existing off-channel storage within this area was represented by one wetland (FEQ wetland 12). This off-channel storage actually consists of several low wetland areas within the Longacres race track site discharging to Springbrook Creek in three locations; however, to simplify the hydraulic simulation of these wetlands, one stage-storage relationship and one hydraulic connection to Springbrook Creek was developed. This information was based upon the preliminary drainage study information developed as a part of the Boeing Master Plan Development for the entire longacres site. The main difference between the proposed CSTC stormwater plan and the ESGRW Plan modeling is the added flood storage particularly at the lower elevations. For example, the FEQ model specified 6.7 ac-ft of storage at elevation 11 for the entire Longacres site. The TIR proposes to add approximately 20 ac-ft of storage at this elevation. Therefore, if the FEQ model was modified to add this additional storage (and no other changes are made), then this additional storage would contribute to attenuation of Springbrook Creek peak flows. Another change from the FEQ model is the discharge location. As mentioned above, the existing Longacres site was assumed to have one discharge point located south of SW 19th Street. In actuality, the existing CSTC site discharges into Springbrook Creek north of SW 19th Street and the remaining Longacres site has two or three discharge points south of SW 19th Street. We understand that Boeing's plans for the ultimate development of entire Longacres site may be to use this northerly discharge. This would result in a slight reduction of Springbrook Creek water surface elevations south of the proposed discharge point. This is because the portion of Springbrook Creek between the northerly discharge point and the southerly discharges would have lower peak flows. This assumes that no flood storage provided at the southerly discharge location is disconnected from the system. ' Personal Communication. Shelley Sundgren, Engineer, CH2M Hill. June 24, 1992. 1159WWO.588 15 09/11/92 D. Miscellaneous Comments 1. MIA versus EIA In representing pre-developed site conditions, the TIR estimates the runoff curve number assuming that all impervious areas are "Mapped Impervious Areas" (MIA) as opposed to "Effective Impervious Areas" (EIA). MIA is defined as the area shown on aerial maps to be impervious areas such as buildings, roads and other paved areas. The EIA is defined as the portion of the MIA that is directly connected to the drainage collection system. Although it does not appear to be a requirement in the KCSWDM to account for EIA, studies have shown that the runoff curve number for MIA should be discounted because runoff from these areas flows overland prior to entering a collection system and therefore some infiltration occurs. The assumption used in the TIR results in slightly higher predicted outflows from the pre-developed site. A rough estimate of the difference in runoff volume was made considering the MIA versus the EIA for the CSTC site. It was assumed that 30% of the site's 20 acre MIA was non-effective impervious area. It was also assumed that the non-effective impervious area had runoff characteristics similar to lawns or landscaped area. This change resulted in a reduction of the runoff volume of only I acre foot. The effects of conserving EIA versus MIA are therefore negligible for the CSTC. 2. Soils Information Approximately 58% of the pervious area within pre-development Subbasin 3 were PP Y P P P identified as having Ur (Urban Modified Soils). It was assumed that these soils have SCS Group D runoff characteristics. Group D soils have high runoff rates compared to other soil groups. This assumption may result in the prediction of higher pre- and post- development runoff rates and volumes than actually exist. KCSWDM Special Requirement number 12, Soils Analysis and Report, contains a requirement for soils investigations when insufficient soils information is available. This would often be an issue because overestimating the pre-development runoff rates can reduce the volume requirements for detention facilities. For example, a development which converts pervious C group soils to impervious surfaces would require more detention storage than converting pervious D group soils to impervious surfaces. This does not appear to be an issue with the CSTC facility however, because the CSTC facility proposes only a small reduction in the area of D group soils, as shown below. Pre-development Percent of Area (Subbasin 3) Impervious 27 Pervious, Ur (D group) 58 Pervious, Py (B group) 8 Pervious, Ur (C group) 7 1159WWO.588 16 09/11/92 iPost-development Percent of Area (Subbasin C) Impervious 35 Pervious, Ur (D group) 56 Pervious, Py (B group) 7 Pervious, Ur (C group) 2 1 Should future plans include directing stormwater from the south portion of the Longacres race track to the CSTC storage facilities, additional soils investigations to determine the runoff characteristics of the Ur soils would be recommended. E. Conclusions/Recommendations Based upon our review of the TIR and associated information, the CSTC satisfies the FEMA and City requirements for development in the floodplain provided that the floodway be illustrated on the site improvement plans (Special Requirement number 9) and it is found that the development proposes no filling in the floodway. The CSTC surface water controls are planned to provide more post-development flood storage than under pre-developed conditions, and the post-developed peak discharges into Springbrook Creek will be less than under pre-developed conditions. 1159WWO*... 17 09/11/92 r m m 4m mm i LIM M r� APPENDIX Appendix Number Description 1 References 2 Figure 4 - Springbrook Creek Water Surface Profile (Taken from the ESGRW Plan Hydraulic Analysis Report - Existing Drainage System, March 1992) 3 Figure 3 - Major Drainage System Modeled By FEQ (Taken from the ESGRW Plan Hydraulic Analysis Report - Existing Drainage System, March 1992) 4 Figure 4 - Springbrook Creek Water Surface Elevation Profiles (Taken from the ESGRW Plan Hydrologic Analysis Report, December 1991) 5 KCSWDM Special Requirement Number 7 6 TIR Addendum No. 1 7 KCSWDM Special Requirement Number 8 8 KCSWDM Special Requirement Number 9 ' 1159WWO.588 18 09/11/92 REFERENCES (1) Federal Emergency Management Agency. 1989. Flood Insurance Study, King County, Washington, Federal Emergency Management Agency. (2) Northwest Hydraulic Consultants. December 1991. Eastside Green River Watershed Hydrologic Analysis. R.W. Beck and Associates and the City of Renton. (3) R.W. Beck and Associates. March 1992. Eastside Green River Watershed Plan Hydraulic Analysis, Existing Drainage System. City of Renton. (4) Personal Communication. Shelley Sundgren, Engineer, CH2M Hill. June 24, 1992. (5) Hydrologic Engineering Center, Water Resources Support Center, U.S. Army Corps of Engineers. May 1990. Procedures for Compliance with Floodway Regulations. Federal Emergency Management Agency. f Public Works (6) King County Department o , Surface Water Management Division. January 1990. King County, Washington Surface Water Design Manual, King County Department of Public Works, Surface Water Management Division. 1159WW0.588 19 09/11/92 SP T RINGBROOK CREEK WATER SURFACE ELEVATION PROFLE RADo,o,o LEGEND EXUTING CHANNEL SYSTEM —�CAUFRE�NT//FUTURE LAND USE CONDf KM y High Springbrook Creek Flows (Conveyance) YEAR EVBSI Current Land Use Conditions High Springbrook Creek Flows (Conveyance) Future Land Use Conditions ---------- High BRPS Storage (High Green River Flows) Current Land Use Conditions High BRPS Storage (High Green River Flows) Future Land Use Conditions FEMA Base Flood ROADWAY SURFACE 22 20 >, TOP OF CULVERTS 18 � a� o — V) n- m 14 -_ - - — - - - -- - — 4-+ 0 10 _ - N V N W r- 3 3 V N 6 BOTTOM OF CULVERTS v 3 4 N • 2 Bottom Profile EAST SIDE GREEN RIVER WATERSHED PLAN HYDRAULIC ANALYSIS REPORT 0 FIGURE 4 SPRINGBROOK CREEK —2 WATER SURFACE PROFILE 0 5000 10000 15000 R-W. BECK _ Distance (ft) ArroToa i .............. ............. ........... .Y.........,.......... - RAD01015 .. i _ , /1 ............... s 'r �<• i , I p5 ... . . ... i ,... ... , SA.�C...;,:, L :..............•, �\�`,: __:.: !i �t'!i i 3 t • v .. i ... .f a >.•�.�37,Sf f S` —, CREEK �1LAND 1lb PAN„ER . ., ....3? L...... , y ` ,,tom. ..., •7' ;« \ ... �.. i ,_..............._.............. - n ........ J�7 G ..s si ;.•/ ..... .. i y y ... .. i...-.... .... . 1 : : ii i r ' 1 l , , I 16 ...... .. t 00 „ + :1 t 1 ...:._ _ ... .... . , t: ♦ .............__.............._ SCALE __.... ... 1 =1000 t, ♦ , ; ......... .._............ 10 zg i ,....•. -... i i . SpR�N��PNNE�1 12 C o cr- cl- CIO i < 517 `\ _ .,..♦...., 'f :! f 1 t.. ' ] a CREEK PUAP STATION , FOREBAY ... .._ \ ........-.... ....... .... G tt t.. ......... EAST PLAN ................ R - HYDRAUUC ANALYSIS REPORT D BLACK RIVER :.y _ LEGEND FIGURE 3 PUMP STATION �` CONVEYANCE SYSTEM MODELED MAJOR DRAINAGE SYSTEM MODELED BY FEQ - WETLAND NUMBER 4 1 TO GREEN DUWAMISH R.W. BECK \ APPROXIMATE SUBBASIN BOUNDARY r RIVER �> PANTHER CREEK 5 AM `: AND ASSOCL 3 CITY OF RENTON Planning/Building/Public Works Department Earl Clymer, Mayor Lynn Guttmann,Administrator December 10, 1993 k � Andrew Clapham ' The Boeing Co. �I•.�' 1 © 1993 P.O. Box 3707, MS 6Y-50 CITY OF RENTON Seattle, WA 98124-2207 Engineering D,;pt. SUBJECT: CSTC Site Development Project Closeout Requirements Dear Mr. Clapham: As the CSTC project moves toward completion, there will come a time when we will want to closeout the public works permits and move toward appproving occupancy permits. There are several items which must be completed before we can complete the project closeout for this Public Works permit. These items include: 1 . Completion of all utility, drainage, paving, grading, lighting, landscaping and street improvements for the project. This includes any punchlist items from the Public Works Inspector and/or the City Maintenance Division. The construction permit for the project must be signed off by the inspector (Mary Burgy) prior to completing project closeout. 2. Submittal to the inspector of test reports for all backflow prevention devices by a certified backflow device testing company. These test reports must be submitted for all backflow prevention devices before the inspector will schedule the walkthrough with the City Maintenance Division. We cannot recommend approval of any temporary occupancy requests until the Maintenance Division has completed its project walkthrough. 3. As-built plans must be submitted to the City for our review and approval. Submit three (3) blue-line copies for our review. After approval of the blue-line plans, final mylars must be submitted for our permanent records. Final as-built plans must be approved by the City prior to recommending final occupancy. 4. Bills of Sale and Cost Data Inventories must be prepared and submitted to the City for review, approval and recording for all improvements being turned over to the City. Standard forms are available at the 4th floor information counter. Separate documents must be submitted for the storm main system in SW 16th St which will be turned over to the City of Tukwila. 5. Final utility easements for the publicly owned and maintained water appurtenances on the site, as well as the required quit claim deed for the street dedication must be submitted, approved and recorded. Please submit all easements for our review and approval before signing and notarizing by the property owner. We will return for final signature and notarization once the legals and easement forms have been approved by our Technical Services Section. 200 Mill Avenue South - Renton, Washington 98055 December 10, 1993 Page 2 6. After the construction permit is signed off by the inspector, a maintenance bond must be posted with the City for 10% of the value of the improvements to be turned over to the City. The original construction bond can be released after the maintenance bond is accepted by the City. Sample forms for the maintenance bond are available at the 4th floor information counter. 7. Payment to the City for all overtime charges for inspection, and water connection charges related to the project 8. The approved code modification/alteration request for this project included conditions which must be implemented before we can recommend final occupancy for project. A copy of the conditions of the approved code modification/alteration request is attached. These project close out items will be coordinated through the Plan Review Section. Please note that review and approval of the submitted items may take several weeks, and longer if there are corrections required. You should submit these items as soon as possible to allow time for processing. The approval of the final occupancy permit is made by the Construction Field Services Section. The request for temporary and final occupancy is handled by the Building Inspector (Randy Martin), who will route the request to all affected departments for comment. The items listed in this letter are only the items related to the public works portion of the project. There may be other items which will need to be addressed from the Building Inspector or other City departments. Sincerely, Neil Watts, P.E. Plan Review Supervisor Development Services Division cc: Jim Chandler Jim Hanson Ron Straka Clint Morgan Mary Burgy Attachment CITY OF RENTON MEMORANDUM DATE: May 20, 1992 TO: Gregg Zimmerman Tom Kriss 1 Lenora Blauman I FROM: Ron Straka SUBJECT. The Boeing Company's Customer Service Training Center Project Code Modification/Alteration Request The Surface Water Utility has reviewed the Boeing Company's code modification/alteration request for the Customer Service Training Center(CSTC)project as allowed under Ordinance No.4342. The Boeing Company has requested code modification/alteration to the City of Renton Storm and Surface Water Drainage chapter 4-22. The code modification/alteration request (see attached documents)pertains to the portions of the City adopted 1990 King County Surface Water Design Manual (KCSWDM) Core requirement No 3 (biofiltration requirement) and Special Requirement No. 6 (coalescing plate oil/water separators)surface water management standards. The Surface Water Utility approves of the requested code modification/alteration request based upon the + information provided by the Boeing Company (see attachments). This information includes a technical letter from Dr. Richard R. Homer who teaches at the University of Washington's Environmental Engineering and Science Department. Dr. Horner a nationally respected expert in the field of water quality and resource engineering. Dr Homer reviewed the code requirements for the Boeing CSTC project and estimated the pollutant removal that would be obtained. He then reviewed the proposed storm and surface water management facilities design for the Boeing CSTC and estimated the percentage of pollutant removal that would be achieved by the Boeing system. This comparison shows that the proposed Boeing CSTC storm and surface water management plan will remove more pollutants than the code requirements would for the selected parameters. I The Surface Water Utility approves the code modification/alteration request based upon this evidence and accepts the conceptual drainage plan for the Boeing CSTC project. The request demonstrates that the proposed design meets the intent of the code,will accomplish equivalent pollutant removal as required by code(actually exceeds code requirements), it will equally protect the environment and satisfies the other requirements of Ordinance No 4342 as discussed in the formal request. 1 As allowed by Ordinance No 4342, the following conditions of this approved code modification/alteration request must be complied with by the Boeing Company as specified in the conditions. The conditions of the code modification/alteration request are as follows: 1.) The applicant (The Boeing Company)shall develop a Water Quality Monitoring and Assessment Plan to be approved by the City of Renton Surface Water Utility. The Utility recommends that the Boeing Company receive direction from Dr.Horner in the development of the Water Quality Monitoring and Assessment Plan. This condition must be complied with prior to the issuance of the CSTC projects construction/building permit. 2.) The applicant shall implement the approved monitoring plan with continuous monitoring for a period of time as specified in the approved plan based upon Dr.Hornet's recommendations. The water quality monitoring shall start following the completion of construction at the time of the projects Final Occupancy Permit issuance(CSTC building). ' 3.) Upon completion of the approved water quality monitoring period, the applicant shall provide within two months the City of Renton with technical report which documents the results of the water quality monitoring and assess the effectiveness of the proposed systems pollutant removal rate for comparison with code pollutant removal rates. If the proposed CSTC storm and surface water systems pollutant removal rates are less than what the code requirement pollutant removal rates are, then the Boeing Company shall install the required coalescing plate oil/water separators, or propose alternate measures which may be subject to additional conditions by the City of Renton Surface Water Utility. 4•) The applicant (Boeing)shall provide the City of Renton with a bond that is valid for the duration of the approved water quality monitoring duration period plus six months,which is equal to 100% of the cost to design/construct/install the projects required coalescing plate oil/water separators. These conditions are justified in order that the proposed CSTC storm and surface water management system works as certified by the applicants engineer and to ensure protection of the public's safety and health as well as the environment. If you have any questions regarding this subject,please contact me at(206)277-5547. (� f I i f r r SPRINGBROOK CK. WATER SURFACE ELEVATION PROFILES r Initial Final Final/Critical at SW Grady Way Culvert ' - Invert o s v-o-o Invert o-& � Invert Q= 800 cfs — — — Q= 800 cfs ------ Q= 800 cfs ' Q= 1000 cfs — — -- Q= 1000 cfs ------ Q= 1000 cfs 22 Q= 1500 cfs — — — Q= 1500 cfs ------ Q= 1500 cfs r _ 20 18 1 16 __=====J __-___ r — — ------- ____-----r-- _ _ ——In r 14 --- 1 r 12 , _ - - -_ _ _ - - co _-- co r , , , _ co ca 0 — — — 8 i co N 6 co 4 Note: Discharges are for BRPS ' entrance section. See Table 5 2 for specification of discharge -a— r--- ------a--� for different profiles a n d locations. 0 1 _2 p 5000 10000 15000 ' Distance (ft.) Black River Pump Station i Figure 4 r KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL ' 1.3.7 SPECIAL REQUIREMENT #7: CLOSED DEPRESSIONS Closed depressions are low-lying areas which have no, or such a limited, surface outlet that in most storm events the area acts as a retention basin, holding water for infiltration Into the ground or evaporation into the air. By their nature many closed depressions may contain wetlands which will require projects to meet the requirements of the Sensitive Areas Ordinance and Rules. ' Threshold Requirement IF a proposed project will discharge THEN the project must meet the runoff to an existing closed depression requirements below: ' that has greater than 5,000 square feet of surface area at potential overflow . . . (1) when a closed depression is contained solely on a project site, the volume of rainfall ' previously contained by the closed depression must be retained in dead storage on-site; AND (2) the volume of runoff from the project to any off-site closed depression must not Increase, except as allowed under the conditions of Special Requirement #8: Use of Lakes, Wetlands ' or Closed Depressions for Peak Rate Runoff Control. On-sfte infiltration and retention are the two potential mechanisms that may assist in satisfying these ' requirements. Section 3.6 provides additional discussion on how to apply the hydrologic analysis to meet these requirements. Chapter 4, Section 4.5, contains the analysis and design of infiltration systems. ' Due to the significant adverse impacts which can result from increasing the rate and volume of runoff to closed depressions, they must be analyzed for the two-, ten-, and 100-year, 24-hour duration, and the 100-year, seven-day duration design storm events. Potential overflow routes shall be analyzed to address potential adverse impacts per Core Requirement #2: Off-Site Analysis in Section 1.2.2. r 1.3.7-1 1/90 os 822-�3Q{ R�+©��►'�[�� �:#�..go��706��fi�4rtar3d>V�asfi�ngtcx�;�8�183-�7s2 �hor� �2 �.;;> , ;;<.; ' TO: R W Beck DATE: 6/17/92 2101 4th Avenue Suite 600 PHONE: 441-7500 ' Seattle,Wa 98121-2375 ATTN: Mike .; JOB NO. 40547 PROJECT: CSTC Site Development, Contract No. BECE 90-8002-AC ' HEREWITH UNDER SEPARATE COVER ;.� ' THE FOLLOWING IS TRANSMITTED Lj FOR YOUR USE OR DISTRIBUTION FOR YOUR REVIEW AND COMMENTS ' FOR CORRECTION &RESUBMITTAL ' QUANTITY DESCRIPTION 1) 2 Copies Overall Site Grading Plan- 1C(G) plotted 5/29/92 2) 1 Copy Closed Depression Analysis of Floodplain Sill during 100-year 7-day Event ' THIS TRANSMITTAL IS PER NORMAL PROCEDURE YOUR LETTER ' YOUR FAX YOUR TELEPHONE REQUEST ' DATED: FROM YOUR TO OUR ' REMARKS: For grading information only. SVERDRUP CORPORATION CC: SF 4.1 ' BY: *S-cQttlC4iviIngineer ' 0617TRAN.XLS KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL 1.3.8 SPECIAL REQUIREMENT #8: USE OF LAKES, WETLANDS OR CLOSED DEPRESSIONS FOR PEAK RATE RUNOFF CONTROL 1brLshQ1_d Requirement IF a project proposes to use a lake, THEN the project must: wetland or closed depression for peak meet all requirements of the rate runoff control consistent with Core (a) Sensitive Areas Ordinance and Requirement 3: Runoff Control . . • Rules for such use; (b) include water quality controls consistent with Special Requirement #5: Special Water Quality Controls; AND (c) observe limits on any Increases to the floodplain as described below. Sensitive Areas Ordinance As lakes and wetlands are sensitive areas by definition, the rules contained in the Sensitive Areas Ordinance and Rules must be met, even if the particular water body was not included in the County Wetlands Inventory. Note: review under the Sensitive Areas Ordinance may result in precluding the use of a lake, wetland or closed depression as a retention/detention facility in many cases. Water Quality Controls The controls specified under Special Requirement #5: Special Water Quality Controls in Section 1.3.5 must be met if the proposed project will construct more than one (1) acre of impervious surface that will ' be subject to vehicular use or storage of chemicals. F000dplain The increased volume of runoff from the proposed project, (and the increased volume of runoff from equivalent* potential developed tributary area) may not increase the 100-year floodplain elevation of a lake, wetland, or closed depression more than 0.1 feet unless: (1) The lake, wetland, or closed depression is contained totally on the proposed project site; AND (2) There are no existing flooding problems; AND (3) The outlet control will be modified so that the peakproject es f o scow from for the 2 lake,10etorn100 r closed depression with construction of the proposed p of 24-hour or 100-year, seven-day duration design storms, and to allow adjustment for future control of the entire tributary basin for full build-out developed runoff conditions (based on current zoning or community plan, whichever is the higher density use); AND (4) The applicant has secured drainage easements from all of the property owners abutting the lake, wetland, or closed depression for the change in the floodplain on their property and for access to ' the control structure; AND (5) All other permits required for such outlet control changes (such as a King County Shorelines permit and several of those from the other agencies listed in the beginning of this chapter) for such outlet control changes have been secured. *Equivalent potential developed area is defined as sub-basin area tributary to the water body within an equal distance from the water body as the highest point on the proposed project site analyzed at potential developed conditions (based on existing zoning, or proposed land use in an adopted ' Community Plan, whichever has the potential for the most impervious surface). • 1.3.8-1 1/90 i KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL 1.3.9 SPECIAL REQUIREMENT #9: DELINEATION OF 100 YEAR FLOODPLAIN 1 1Lr&shQ1_d Bkohgmgnt IF a proposed project contains or abuts THEN the 100 year floodplain a stream, lake, wetland or closed boundaries (and floodway, If available, depression, or if other King County or If development is proposed within the regulations require study of flood 100 year floodplain), based on an hazards. . . approved flood hazard study as described below, shall be delineated on the site improvement plans and profiles, and on any final subdivision maps 1 prepared for the proposed project. ' Approved Flood Hazard Study If an approved flood hazard study exists, then it may be used as basis for delineating the floodplain and floodway boundaries provided it was prepared in a manner consistent with this Manual and other King County flood hazard regulations. If an approved flood hazard study does not exist then one shall be prepared based on the requirements described in section 4.3.8 in Chapter 4. A600 1 i 1 1 i 1 1 ! 1.3.9-1 1/90 POND-2 Version: 5. 17 SIN: Page 1 EXECUTED: 06-17-1992 09 : 38 : 49 ********************************************************************* * * * CSTC SITE DEVELOPMENT * PROPOSED SILL LOCATION: NE MEADOW, PROPOSED TOPOGRAPHY * CLOSED DEPRESSION WITH 100-YEAR 7-DAY STORM EVENT * SVERDRUP CORPORATION 4/13/92 (run 6/16/92 for RW Beck question) * * ********************************************************************* Inflow Hydrograph: a:NEWC1007.HYD Rating Table file: a: 0413PWP .PND ----INITIAL CONDITIONS---- Elevation = 8 . 00 ft Outflow = 0. 00 cfs Storage = 0. 00 ac-ft INTERMEDIATE ROUTING GIVEN POND DATA COMPUTATIONS ' ---- ------- ------- ---- ---- - - ELEVATION OUTFLOW STORAGE- ---- ------- 2S/t 2S/t--+-0-- (ft) (cfs) (ac-ft) (cfs) (cfs) 00 ----8. - ------0. 0 001 --- -----0. 001 --------0. 0- ---------0. 0 00 8 . 25 0. 0 0. 003 0. 1 0. 1 8 . 50 0. 0 0. 010 0. 2 0. 2 8 . 75 0. 0 1.450 35 . 1 35. 1 9 . 00 0. 0 3 . 303 79 . 9 79 .9 9 . 25 0. 0 5.460 132 . 1 132 . 1 ' 9. 50 0. 0 7 .781 188 . 3 188 .3 9 .75 0. 0 10. 272 248. 6 248 . 6 10. 00 0. 0 12 .940 313 . 1 313 . 1 10. 25 0. 0 15.762 381. 4 381.4 ' 10. 50 0. 0 18 .717 453 . 0 453 . 0 10. 75 0. 0 21.808 527 . 7 527 .7 11. 00 0. 0 25. 037 605. 9 605.9 ' 11. 25 0. 0 28. 416 687 .7 687 .7 11. 50 0. 0 31. 956 773 . 3 773 . 3 11.75 0. 0 35. 662 863 . 0 863 . 0 ' 12 . 00 0. 0 39. 536 956. 8 956. 8 12 . 25 0. 0 43 .529 1053 .4 1053 .4 12 . 50 0. 0 47. 592 1151. 7 1151.7 12 .75 0. 0 51.724 1251.7 1251. 7 ' 13 . 00 0. 0 55.926 1353 . 4 1353 . 4 13 . 25 0. 0 60.215 1457 . 2 1457 . 2 13 . 50 0. 0 64 . 609 1563 . 5 1563 . 5 ' 13 . 75 0. 0 69. 110 1672 . 4 1672 .4 14 . 00 0. 0 73 .717 1784 . 0 1784 . 0 14 . 25 0. 0 78. 448 1898 . 4 1898. 4 14 . 50 0. 0 83 . 317 2016. 3 2016. 3 ' 14 . 75 0. 0 88 . 327 2137 . 5 2137. 5 15. 00 3 . 6 93 . 480 2262 . 2 2265. 8 15. 25 25. 2 98 .747 2389 . 7 2414.9 ' 15. 50 61. 2 104 . 099 2519 . 2 2580. 4 EXECUTED 06-17-1992 09 : 38:49 Page 2 DISK FILES: NEWC1007 .HYD 0413PWP .PND ' INTERMEDIATE ROUTING GIVEN POND DATA COMPUTATIONS ELEVATION OUTFLOW STORAGE 2S/t 2S/t + 0 (ft) (cfs) (ac-ft) (cfs) --- (cfs) -------- --------- ---------- ----- ---- - ---- ' 15.75 111.7 109. 538 2650. 8 2762 . 5 16. 00 177. 0 115. 064 2784 . 5 2961.5 16. 25 263 .2 120.741 2921. 9 3185. 1 ------------------------------ -------------------------- Time increment (t) = 1. 000 hrs. POND-2 Version: 5. 17 SIN: Page 3 EXECUTED: 06-17-1992 09 : 38: 49 Pond File: a: 0413PWP .PND Inflow Hydrograph: a:NEWC1007 .HYD Outflow Hydrograph: a:OUT .HYD INFLOW HYDROGRAPH ROUTING COMPUTATIONS TIME INFLOW I1+I2 2S/t - O 2S t + O OUTFLOW ELEVATION (hrs) (cfs) (cfs) (cfs) (cfs) -- (cfs) -- --(ft---- ________ ____ --------- - __ ---- ---- ---- 0. 000 0. 00 _____ 0. 0 _ 0. 0 0. 00 8. 0 1. 000 0. 12 0. 1 0. 1 0. 1 0. 00 8 . 35 2 . 000 0. 27 0. 4 0. 5 0. 5 0. 00 8 . 50 3 . 000 0. 44 0.7 1. 2 1. 2 0. 00 8. 51 4 . 000 0. 51 1. 0 2 . 2 2 . 2 0. 00 8 . 51 5. 000 0. 67 1. 2 3 . 4 3 . 4 0. 00 8 . 52 6. 000 0 . 87 1. 5 4 . 9 4 . 9 0. 00 8. 53 7 . 000 1. 09 2 . 0 6. 9 6. 9 0. 00 8. 55 8 . 000 1. 20 2 . 3 9 . 2 9 . 2 0. 00 8 . 56 ' 9 . 000 1. 40 2 . 6 11. 8 11. 8 0. 00 8 . 58 10. 000 1. 60 3 . 0 14 . 8 14 . 8 0. 00 8 . 60 18 . 1 18 . 1 0. 00 8. 63 11. 000 1.77 3 .4 21. 8 0. 00 8 . 65 ' 12 . 000 1. 92 3 .7 21. 8 13 . 000 2 . 11 4 . 0 25.9 30. 0. 00 8. 14 . 000 2 . 31 4 . 4 30. 3 . 3 0. 00 8 .72 15. 000 2 . 64 5. 0 35. 2 35 . 2 0. 00 8 .75 16. 000 2 . 84 5. 5 40. 7 40.7 0. 00 8 .78 17 . 000 3 . 04 5.9 46. 6 46. 6 0. 00 8 . 81 18 . 000 3 . 20 6. 2 52 . 8 52 . 8 0. 00 8 .85 ' 19 . 000 3 . 35 6. 6 59. 4 59 . 4 0. 00 8• 89 20. 000 3 . 54 6. 9 66. 3 66. 3 0. 00 8.92 21. 000 3 . 84 7 . 4 73 . 6 73 . 6 0. 00 8 .96 22 . 000 4 . 04 7 . 9 81. 5 81. 5 0. 00 9 . 01 ' 23 . 000 4 . 24 8. 3 89 .8 89. 8 0. 00 9 . 05 24 . 000 4 . 44 8.7 98 . 5 98 . 5 0. 00 9 . 09 25. 000 4 . 60 9 . 0 107 . 5 107 . 5 0. 00 9 . 13 ' 6. 000 475 9 . 4 116.9 116. 9 0. 00 9 . 18 2 . 126.7 12.75 9. 8 6. 7 0. 00 9 .22 27 . 000 0. 00 9 . 28. 000 5. 24 10. 3 136.9 136. 9 29. 000 5. 44 10.7 147 . 6 147 . 6 0. 00 9 . 32 ' . 000 5. 65 11. 1 158 .7 158 .7 0. 00 9 . 37 30 . 000 585 11. 5 170. 2 170. 2 0. 00 9 . 42 3 .2 . 000 11.9 182 . 1 182 . 1 0. 00 9 . 47 3 . 85 00 12 .4 194 . 4 194 . 4 0. 00 9 . 53 33 . 000 6. 35 34 . 000 6.76 13 . 1 207 .5 207 . 5 0. 00 9 . 58 35. 000 7 . 16 13 . 9 221.4 221.4 0. 00 9 . 64 36. 000 7 . 56 14 .7 236. 2 236. 2 0. 00 9 . 70 37 . 000 7 . 96 15.5 251.7 251.7 0. 00 9 .76 38. 000 8 . 56 16. 5 268. 2 268 . 2 0. 00 9 .83 39 . 000 9 . 01 17 . 6 285. 8 285. 8 0.00 9. 89 40. 000 9 . 56 18 . 6 304 . 3 304 . 3 0. 00 9•97 41. 000 9 . 86 19 . 4 323 . 8 323 . 8 0. 00 10. 04 42 . 000 10. 26 20. 1 343 .9 343 . 9 0. 00 10. 11 43 . 000 10. 56 20.8 364 . 7 364 .7 0. 00 10. 19 44 . 000 10. 96 21. 5 386 . 2 386. 2 ---- ---10_27- POND-2 Version: 5. 17 SIN: Page 4 EXECUTED: 06-17-1992 09 : 38:49 Pond File: a: 0413PWP .PND ' Inflow Hydrograph: a:NEWC1007 .HYD Outflow Hydrograph: a:OUT .HYD ' INFLOW HYDROGRAPH ROUTING COMPUTATIONS TIME INFLOW I1+I2 2S/t - 0 2S/t + O OUTFLOW ELEVATION (hrs) (cfs) (cfs) (cfs) (cfs) (cfs) (ft) ---- - ---------�-- ----------- -------- 22 . 3408 . 6 - --------- 45. 000 11. 37 408 6 408. 6 0. 00 10. 34 46. 000 12 . 52 23 . 9 432 .4 432 . 4 0. 00 10. 43 47 . 000 13.77 26. 3 458 .7 458 . 7 0. 00 10. 52 48 . 000 14 . 57 28 . 3 487 . 1 487 . 1 0. 00 10. 61 49. 000 14 . 67 29 . 2 516. 3 516. 3 0. 00 10.71 50. 000 17 . 37 32 . 0 548 . 4 548 . 4 0. 00 10. 82 ' 51. 000 19 . 93 37 . 3 585. 7 585. 7 0. 00 10.94 52 . 000 25. 55 45. 5 631. 1 631. 1 0. 00 11. 08 53 . 000 39 . 20 64 . 8 695. 9 695. 9 0. 00 11. 27 54 . 000 48 . 16 87 .4 783 . 2 783 . 2 0. 00 11. 53 55. 000 40. 42 88 . 6 871. 8 871. 8 0. 00 11.77 56. 000 31. 31 71.7 943 . 6 943 . 6 0. 00 11.96 ' 57 . 000 28 . 18 59. 5 1003 . 0 1003 . 0 0. 00 12 . 12 58 . 000 19 . 28 47 . 5 1050. 5 1050. 5 0. 00 12 .24 59 . 000 17 . 04 36 . 3 1086.8 1086. 8 0. 00 12 . 33 60. 000 16. 96 34 . 0 1120. 8 1120. 8 0. 00 12 . 42 61. 000 16. 58 33 . 5 1154 . 4 1154 . 4 0. 00 12.51 62 . 000 16. 24 32 . 8 1187 . 2 1187 . 2 0. 00 12 . 59 63 . 000 15. 89 32 . 1 1219 . 3 1219 . 3 0. 00 12 . 67 64 . 000 14 . 34 30 . 2 1249 . 5 1249 . 5 0. 00 12 .74 65. 000 12 .92 27 . 3 1276. 8 1276. 8 0. 00 12 . 81 66. 000 12 . 80 25.7 1302 . 5 1302 . 5 0. 00 12 . 87 67 . 000 12 . 60 25.4 1327 . 9 1327 . 9 0. 00 12 . 94 68 . 000 12 .40 25. 0 1352 . 9 1352 . 9 0. 00 13 . 00 69 . 000 12 . 20 24 . 6 1377 . 5 1377 . 5 0. 00 13 . 06 70. 000 12 . 00 24 . 2 1401.7 1401.7 0. 00 13 . 12 ' 71. 000 11. 80 23 . 8 1425. 5 1425. 5 0. 00 13 . 17 72 . 000 11. 60 23 . 4 1448 .9 1448 . 9 0. 00 13 . 23 73 . 000 11. 40 23 . 0 1471.9 1471. 9 0. 00 13.28 ' 74 . 000 11. 15 22 . 6 1494 . 5 1494 . 5 0. 00 13 . 34 75. 000 10. 68 21. 8 1516. 3 1516. 3 0. 00 13 . 39 76. 000 10. 13 20. 8 1537 . 1 1537 . 1 0. 00 13 .44 77 . 000 9. 89 20. 0 1557 . 1 1557 . 1 0. 00 13 . 48 78 . 000 9 .70 19. 6 1576.7 1576. 7 0. 00 13 . 53 79. 000 9 . 60 19 . 3 1596. 0 1596. 0 0. 00 13 . 57 80. 000 9 . 50 19 . 1 1615. 1 1615. 1 0. 00 13 . 62 81. 000 9 . 40 18 .9 1634 . 0 1634 . 0 0. 00 13 . 66 82 . 000 9 . 30 18 .7 1652 .7 1652 .7 0. 00 13 .70 83 . 000 9. 20 18 . 5 1671. 2 1671. 2 0. 00 13 . 75 84 . 000 9 . 10 18. 3 1689. 5 1689 . 5 0. 00 13 .79 85. 000 8.95 18 . 1 1707 . 6 1707 . 6 0. 00 13.83 86 . 000 8 . 80 17 . 8 1725 . 3 1725. 3 0. 00 13 . 87 87 . 000 8. 75 17 . 6 1742 . 9 1742 . 9 0. 00 13 .91 88 . 000 8 . 55 17 . 3 1760. 2 1760. 2 0. 00 13 .95 89 . 000 8 . 40 17 . 0 1777 . 1 1777 . 1 0. 00 13 . 98 90. 000 8 . 25 16.7 1793 . 8 1793 . 8 0. 00 14 . 02 ------------------ ------------------------------------------------------ POND-2 Version: 5. 17 SIN: Page 5 EXECUTED: 06-17-1992 09 : 38 : 49 Pond File: a: 0413PWP .PND Inflow Hydrograph: a:NEWC1007 .HYD Outflow Hydrograph: a:OUT .HYD INFLOW HYDROGRAPH ROUTING COMPUTATIONS ' 2S t - 0 2S/t INFLOW Il+I2 / / 2S t + O OUTFLOW ELEVATION (hrs) (cfs) (cfs) (cfs) ( ) -(cfs) cfs (ft ________ _ ---------- - ----- -----�--- -------- --------- ------------ 91. 000 8 . 15 16. 4 1810. 2 1810. 2 0. 00 14 . 06 92 . 000 8. 10 16. 3 1826.4 1826. 4 0. 00 14 . 09 93 . 000 8 . 05 16. 2 1842 . 6 1842 . 6 0. 00 14 . 13 94 . 000 7 . 95 16. 0 1858 . 6 1858 . 6 0. 00 14 . 16 95. 000 7 .90 15.9 1874 .4 1874 . 4 0. 00 14 . 20 96. 000 7 . 85 15. 8 1890. 2 1890. 2 0. 00 14 . 23 ' 97 . 000 7 .80 15.7 1905. 8 1905. 8 0. 00 14 . 27 98 . 000 7 . 75 15. 6 1921. 4 1921.4 0. 00 14 . 30 99 . 000 7 . 65 15. 4 1936.8 1936. 8 0. 00 14 . 33 1 100. 000 7 . 60 15. 3 1952 . 0 1952 . 0 0. 00 14 . 36 101. 000 7 . 55 15. 2 1967 . 2 1967 . 2 0. 00 14 . 40 102 . 000 7 . 45 15. 0 1982 . 2 1982 . 2 0. 00 14 .43 103 . 000 7 . 30 14 . 8 1996.9 1996. 9 0. 00 14 . 46 104 . 000 7 . 25 14 . 6 2011. 5 2011. 5 0. 00 14 .49 105. 000 7 . 10 14 . 4 2025. 8 2025. 8 0. 00 14 . 52 106. 000 7 . 05 14 . 2 2040. 0 2040. 0 0. 00 14 . 55 ' 107 . 000 6. 85 13 .9 2053 .9 2053 . 9 0. 00 14 . 58 108 . 000 6. 80 13 . 7 2067 . 5 2067 . 5 0. 00 14 . 61 109 . 000 6. 75 13 . 6 2081. 1 2081. 1 0. 00 14 . 63 ' 110. 000 6. 55 13 . 3 2094 . 4 2094 .4 0. 00 14 . 66 111. 000 6. 40 13 . 0 2107 . 3 2107 . 3 0. 00 14 . 69 112 . 000 6. 35 12 . 8 2120. 1 2120. 1 0. 00 14 .71 113 . 000 6. 15 12 . 5 2132 . 6 2132 . 6 0. 00 14 .74 ' 114 . 000 6. 10 12 . 3 2144 . 4 2144 . 8 0. 20 14 .76 115. 000 5. 95 12 . 1 2155. 4 2156. 5 0. 53 14 . 79 116. 000 5. 80 11. 8 2165. 5 2167 . 1 0. 83 14 . 81 117 . 000 5. 75 11. 6 2174 . 8 2177 . 0 1. 11 14 .83 118 . 000 5. 55 11. 3 2183 .4 2186. 1 1. 36 14 . 84 119 . 000 5. 50 11. 1 2191. 2 2194 . 4 1. 60 14 . 86 120. 000 5.40 10. 9 2198.5 2202 . 1 1.81 14 .88 121. 000 5. 40 10. 8 2205. 3 2209 . 3 2 . 01 14 . 89 122 . 000 5. 40 10. 8 2211.7 2216. 1 2 . 20 14 .90 123 . 000 5. 40 10.8 2217 .7 2222 . 5 2 . 38 14 .92 124 . 000 5.40 10. 8 2223 .4 2228 . 5 2 . 55 14 .93 125. 000 5.40 10. 8 2228.8 2234 . 2 2 .71 14 .94 126. 000 5. 40 10. 8 2233 . 9 2239 . 6 2 . 86 14 . 95 ' 127 . 000 5. 40 10.8 2238. 6 2244 . 7 3 . 01 14 .96 128 . 000 5. 40 10. 8 2243 . 2 2249 . 4 3 . 14 14 .97 129 . 000 5.40 10. 8 2247 .4 2254 . 0 3 . 27 14 .98 130. 000 5.40 10.8 2251. 4 2258 . 2 3 . 39 14 .99 ' 131. 000 5. 40 10. 8 2255. 2 2262 . 2 3 . 50 14 . 99 132 . 000 5. 45 10. 9 2258 . 8 2266. 1 3 . 64 15. 00 133 . 000 5. 50 11. 0 2261.4 2269 . 8 4 . 17 15. 01 134 . 000 5. 50 11. 0 2263 . 3 2272 . 4 4 . 56 15. 01 135. 000 5. 50 11. 0 2264 . 6 2274 . 3 4 . 83 15. 01 136. 000 5. 50 11. 0 2265. 6 ----- 2275_6----- 5_02----- 15_02- ------------------ ----------------------- POND-2 Version: 5. 17 SIN: Page 6 EXECUTED: 06-17-1992 09 : 38 : 49 Pond File: a: 0413PWP .PND Inflow Hydrograph: a:NEWC1007 .HYD Outflow Hydrograph: a:OUT .HYD ' INFLOW HYDROGRAPH ROUTING COMPUTATIONS TIME INFLOW I1+I2 2S/t - 0 2S/t + 0 OUTFLOW ELEVATION (hrs) (cfs) (cfs) (cfs) (cfs) (cfs) _-(ft) ------- ---- --------- ------------ ----------- --------- 137 . 000 5. 50 11. 0 2266. 3 2276. 6 5. 16 15. 02 138. 000 5. 50 11. 0 2266. 7 2277 . 3 5. 26 15. 02 139 . 000 5. 50 11. 0 2267 . 1 2277 .7 5. 33 15. 02 140. 000 5. 50 11. 0 2267 . 3 2278. 1 5. 38 15. 02 141. 000 5. 50 11. 0 2267 . 5 2278 . 3 5. 41 15. 02 142 . 000 5.50 11. 0 2267 . 6 2278 . 5 5. 44 15. 02 143 . 000 5. 50 11. 0 2267 .7 2278. 6 5.46 15. 02 144 . 000 5. 50 11. 0 2267 . 8 2278 .7 5.47 15. 02 145. 000 5. 50 11. 0 2267. 8 2278 . 8 5.48 15. 02 1 146. 000 5. 50 11. 0 2267 .8 2278 . 8 5. 48 15. 02 147 . 000 5. 50 11. 0 2267 .9 2278. 8 5.49 15. 02 148. 000 5. 50 11. 0 2267 . 9 2278 .9 5. 49 15. 02 1149 . 000 5. 50 11. 0 2267 . 9 2278. 9 5.49 15. 02 150. 000 5. 50 11. 0 2267 . 9 2278 . 9 5. 50 15. 02 151. 000 5. 50 11. 0 2267 . 9 2278. 9 5. 50 15. 02 152 . 000 5. 50 11. 0 2267 . 9 2278 . 9 5. 50 15. 02 153 . 000 5. 40 10.9 2267 . 8 2278 . 8 5. 48 15. 02 154 . 000 5. 20 10. 6 2267 . 6 2278 . 4 5. 43 15. 02 155. 000 5. 05 10. 3 2267 . 1 2277 . 8 5. 34 15. 02 156. 000 4 . 91 10. 0 2266. 6 2277 . 1 5. 24 15. 02 157 . 000 4 . 72 9 . 6 2266. 0 2276. 3 5. 11 15. 02 158 . 000 4 . 52 9 . 2 2265. 3 2275. 3 4 . 97 15. 02 159 . 000 4 . 36 8 . 9 2264 . 6 2274 . 2 4 . 82 15. 01 160. 000 4 . 21 8 . 6 2263 . 8 2273 . 1 4 . 66 15. 01 161. 000 3 . 72 7 . 9 2262 . 8 2271. 8 4 . 46 15. 01 162 . 000 3 . 32 7 . 0 2261. 5 2269 . 9 4 . 19 15. 01 163 . 000 2 . 86 6. 2 2259. 9 2267 . 7 3 . 87 15. 00 164 . 000 2 . 44 5. 3 2258 . 1 2265. 2 3 . 58 15. 00 165. 000 1. 98 4 . 4 2255. 5 2262 . 5 3 . 51 14 . 99 166. 000 1. 49 3 . 5 2252. 1 2258. 9 3 . 41 14 .99 167 . 000 1. 13 2 . 6 2248 .2 2254 . 7 3 . 29 14.98 168 . 000 0. 67 1. 8 2243 .7 2250. 0 3 . 16 14 .97 r _________________ _________________________________________ POND-2 Version: 5. 17 SIN: Page 7 EXECUTED: 06-17-1992 09: 38: 49 ****************** SUMMARY OF ROUTING COMPUTATIONS ****************** Pond File: a: 0413PWP .PND Inflow Hydrograph: a:NEWC1007 .HYD Outflow Hydrograph: a:OUT .HYD Starting Pond W.S. Elevation = 8 . 00 ft ***** Summary of Peak Outflow and Peak Elevation ***** Peak Inflow = 48. 16 cfs Peak Outflow = 5. 50 cfs Peak Elevation = 15. 02 ft ***** Summary of Approximate Peak Storage ***** Initial Storage = 0. 00 ac-ft Peak Storage From Storm = 93_ -94ac_ft--- - Total Storage in Pond = 93 . 94 ac-ft Warning: Inflow hydrograph truncated on right side. POND-2 Version: 5. 17 SIN: Page 8 Pond File: a: 0413PWP .PND Inflow Hydrograph: a:NEWC1007 .HYD Outflow Hydrograph: a:OUT .HYD EXECUTED: 06-17-1992 Peak Inflow = 48. 16 cfs 09: 38:49 Peak Outflow = 5. 50 cfs Peak Elevation = 15. 02 ft Flow (cfs) 0. 0 5. 0 10. 0 15. 0 20. 0 25. 0 30. 0 35. 0 40. 0 45. 0 50. 0 55. 0 j .______ , _____ , 7 . 0 - x x 8. 0 - x x 9 . 0 - x x 50. 0 - x x �1. 0 - x x 12* 0 - x x 3 . 0 - x x �4 . 0 - x x 55. 0 - x x �6. 0 - x x 57 . 0 - x x 18. 0 - x x i 9. 0 - x x 0. 0 - x x I1. 0 - x x 62 . 0 - x x 13 . 0 - x x 1;4. 0 - x x 15. 0 - x x �6. 0 - x TIME (hrs) * File: a:NEWC1007 .HYD Qmax = 48 . 2 cfs x File: a:OUT .HYD Qmax = 5. 5 cfs v ti r r rA r R.W. BECK AND ASSOCIATES Fourth & Blanchard Building - 2101 Fourth Avenue - Suite 600 Seattle, WA 98121-2375 - Telephone 206/441-7500 INVOICE CITY OF RENTON DICK ANDERSON, UTILTIY SERVICES MANAGER DEPARTMENT OF PUBLIC WORKS 200 MILL AVENUE SOUTH RENTON, WASHINGTON 98055 Invoice No. : W2-0593 Prof. Svcs. Agreement: WW-1159-BAl-AZ Invoice Date: September 30, 1992 Contract or P. 0. No. : CAG90-033 Client/No. : 1159 Project Description: Engineering services rendered in connection with Boeing flood plain analysis review. (WW-1159-BAl-CA) Compensation: Services of Personnel $319. 12 Special Consultants and Subcontractors (201 .59) Postage 0.52 Supplies 5.00 Printing and Reproduction 35.20 Subtotal 158.25 Fee Due (per attached) _ 128. 10 TOTAL AMOUNT OF THIS INVOICE $286.35 TERMS: Invoices due on receipt. Interest charged on past due amounts. REMITTANCE COPY PROF. SVCS. AGREEMENT WW-1159-BA1-AZ INVOICE DATE Sept. 30, 1992 -------------- -------------- Computation of Fixed Fee Due ---------------------------- Estimated Portion of Work Completed as of 09-30-92: 100% Portion of Total Project Fixed Fee Due as of 09-30-92 (100% of $ 854.00) $ 854.00 Less: Fixed Fee Previously Invoiced 725.90 FIXED FEE CURRENTLY BILLABLE ON THIS INVOICE . . . . . . . . . . $ 128.10 PROF. SVCS. AGREEMENT WW-1159-BAl-AZ INVOICE DATE Sept. 30, 1992 -------------- --------------- Cumulative Amount Invoiced -------------------------- Services of Personnel $ 5,499.75 Postage 3.94 Supplies 7.40 Printing and Reproduction 59.44 Computer Services 105.00 Subtotal . . . . . . . . . . . . . . . . . . . . . $ 5,675.53 Fee 854.00 Total . . . . . . . . . . . . . . . . . . . . . $ 6,529.53 R.W. BECK AND ASSOCIATES , REPORT PC2-RG03-01 090992 01 DIRECT COST ACCOUNT LEDGER WW-1159-BA1-CA (0124) CLIENT NAME...........CITY OF RENTON PAGE...01 COST ACCOUNT NUMBER...WW-1159-BA1-CA (0124) - BOEING FLOOD PLAIN ANALYSIS REVIEW DATE...AUG 1992 COST ACCOUNT MANAGER..GISEBURT, M. WW-1159-BA1-AZ TRANSACTION CODING TRANSACTION DESCRIPTION HOURS COST COMPUTED BILL ---------------------------------- ----------------------------------- ------------- -------------------------- ------------------- TC DATE REF NO GEN LED CLAS ST DESCRIPTION GRD TITL PROJ. NUM. C/B/I APHR ACHR AMOUNT RATE AMOUNT -- ------ ------ --------- ---- -- -------------------- --- ---- ----- ------- ----- ------ ------ ------------ ------ ------------ 11 083192 WW2409 0124 7100 0011 47 GISEBURT MS 07 3030 1.0 S S 0 23.654 32.17 32.17 61.21 61.21 0011 EMPLOYEE LABOR...................... 1.0* 32.17* 61.21* 52 083192 J08241 0124 7200 0031 HERRERA ENVIRONMENTA -191.99 -201.59 0031 SPECIAL CONSULTANTS & SUBCONTRACTORS * -191.99* -201.59* R.W. BECK AND ASSOCIATES REPORT PC2-RG03-01 100792 01 DIRECT COST ACCOUNT LEDGER WW-1159-BA1-CA (0124) CLIENT NAME...........CITY OF RENTON PAGE...01 COST ACCOUNT NUMBER...WW-1159-BA1-CA (0124) - BOEING FLOOD PLAIN ANALYSIS REVIEW DATE...SEP 1992 COST ACCOUNT MANAGER..GISEBURT, M. WW-1159-BA1-AZ TRANSACTION CODING TRANSACTION DESCRIPTION HOURS COST COMPUTED BILL ---------------------------------- ----------------------------------- ------------- -------------------------- ------------------- TC DATE REF NO GEN LED CLAS ST DESCRIPTION GRD TITL PROJ. NUM. C/B/I APHR ACHR AMOUNT RATE AMOUNT -- ------ ------ --------- ---- -- -------------------- --- ---- ----- ------- ----- ------ ------ ------------ ------ ------------ 11 091592 GG3142 0124 7100 0011 47 JAMES M 05 0820 0.5 S S 1 10.096 13.73 6.87 26.14 13.07 11 091592 WW2409 0124 7100 0011 47 GISEBURT MS 07 3030 4.0 S S 0 23.654 32.17 128.68 61.21 244.84 0011 EMPLOYEE LABOR...................... 4.5* 135.55* 257.91* 32 093092 V09158 0124 7200 0046 GO POSTAGE 0.52 0.52 0046 POSTAGE............................. * 0.52* 0.52* 32 093092 V09166 0124 7200 0048 GO COPY CENTER SUPPL 5.00 5.00 0048 SUPPLIES............................ * 5.00* 5.00* 32 093092 V09155 0124 7200 0049 GO KODAK 300 21.60 21.60 32 093192 V09452 0124 7200 0049 SEATTLE TELECOPIER 12.00 12.00 32 093192 V09500 0124 7200 0049 WW KODAK 1.60 1.60 0049 PRINTING AND REPRODUCTION........... * 35.20* 35.20* I -} PURCHASE ORDER ACCOUNT FUND PROG DEPT w o ruNcnoN AMOUNT City "o I Renton 2085 '101 000000 16 53b 30 41 14E� 200MILI.A�r� RENTON,WA.98055 �/—� �(lP �jvIOVla � ' (Cy0 `'430 6, I8(%.OQ (2 235-2618 ti gvc>h�f q/�� fSTRUCTIONS �2ek rP/ti'!�v/^5ely y) Z9 1L92 'I��19� P&A tv 94V' h/�'03/D g, 1. Send invoices in TRIPL LATE to Purchasing Division,City of Renton F A 3,1 g� /, 3 16. — 2. All prices are F.O.B.destination unless otherwise stated. 1 /�2 �/407 3. Indicate the Purchase Order Number on Invoice and all labels. /Jde//1 [g�CaX'1 (0 4. Label all shipments as specified on the Purchase Order,and enclose �a �� -OYVV- k/2 Packing Slip with each shipment. (nf� l 5 6ylb 3S _ Gl3o�ga 3 �' S a-. �00br:4'7 1/ to- R r' BECK L ASSOCIATES �1�9a 9 !� 97� DENvER NATL BANK — P1400 W2'dS3 36 �� 112: SEVENTEENTH ST /11 z1 y2- j� a.t )/ao- 9 28� 3S DENVFR, ''0 80202 QUANTITY UNIT DESCRIPTION UNIT PRICE ESTIMATED AMOUNT C F N F I R M I N 6 Y i L .'' . BOE-ING CSTC PFRMIT REVIEW r ,7R0.00 b5780.00 CHAPTER 116, LAWS OF 1965 FLGQU P / I Iv CITY OF RENTON CERTIFICATION i I, THE UNDERSIGNED DO HEREBY CERTIFY UNDER PENALTY OF PERJURY,THAT THE MATERIALS HAVE BEEN FURNISHED, THE SERVICES RENDERED OR THE LABOR PERFORMED AS DESCRIBED HEREIN,AND THAT THE CLAIM IS A JUST, DUE AND UNPAID OBLIGATION AGAINST THE CITY OF RENTON, AND THAT I AM AUTHORIZED TO AUTHENTICATE AND CERTIFY TO SAID CLAIM. SIGNE 'LNG/BLDG/PUB WKS UTILITY SY-. i I I AUTHORIZED BY TOTAL 6, 7 b 0.0 0 ALPHA DP 118 9/90 N " t� 0.10208�� R.W. BECK AND ASSOCIATES Fourth & Blanchard Building - 2101 Fourth Avenue - Suite 600 Seattle, WA 98121-2375 - Telephone 206/441-7500 INVOICE CITY OF RENTON ' ' DICK ANDERSON UTILTIY SERVICES MANAGER DEPARTMENT OF PUBLIC WORKS 200 MILL AVENUE SOUTH iT`( CF FF-111TLi`1 RENTON, WASHINGTON 98055 Invoice No. : W2-0593 Prof. Svcs. Agreement: WW-1159-BA1-AZ Invoice Date: September 30, 1992 Contract or P. 0. No. : CAG90-033 Client No. : 1159 Project Description: Engineering services rendered in connection with Boeing flood plain analysis review. (WW-1159-BAl-CA) i Compensation: Services of Personnel $319.12 Special Consultants and Subcontractors (201.59) Postage 0.52 Supplies 5.00 Printing and Reproduction 35.20 Subtotal 158.25 Fee Due (per attached) 128.10 TOTAL AMOUNT OF THIS INVOICE $286.35 CONCURRENCE � DATE AME INI AL/DATE I !!2 z i { i TERMS: Invoices due on receipt. Interest charged on past due amounts. ORIGINAL R.W. BECK AND ASSOCIATES 2101 Fourth Avenue,Suite 600■Seattle,Washington 98121.2375■USA Telephone(206)441-7500■Fax(206)441-4964 Consulting,(206)441-4962 Engineering Telex 4990402 BECKSEA WW-1159-BA1-CA August 31, 1992 3008 D Mr. Ron Straka ` Actin Storm Water Utility Engineering Supervisor g y g g - 1 1992 City of Renton S ' 200 Mill Avenue South Renton, Washington 98055 CITY OF RE^1T01`a Engineering Dept. Dear Ron: Subject: BOEING CSTC - Floodplain Analysis Review Contract No. CAG-03390 - Invoice No. 3 - July Enclosed herewith is our invoice and cost documentation for the month of July. Please disregard the amount shown on the invoice. The correct invoice amount is $872.42. Our accounting department mistakenly added a subconsultant fee of $201.59 Which should have been added to the BRWQMP project. To correct the City's and our accounting books, a credit in the amount of $201.59 will be included in the next months invoice. Work during the month of July included the development and submittal of the technical memorandum. If you should have any questions, please call our office. Very truly yours, R. W. BECK AND ASSOCIATES Michael S. Gi eburt Project Manager MSG/cs Enclosure (MS(3.059) Boston,MA■Columbus,NE■Denver,CO■Indianapolis,IN■Minneapolis,MN Nashville,TN■Orlando,FL■Phoenix,AZ■Sacramento,CA■Seattle,WA sas•J A ltcv:ycled 1'apet 1'nxitict R.W. BECK AND ASSOCIATES Fourth & Blanchard Building - 2101 Fourth Avenue - Suite 600 Seattle, WA 98121-2375 - Telephone 206/441-7500 INVOICE CITY OF RENTON DICK ANDERSON, UTILTIY SERVICES MANAGER DEPARTMENT OF PUBLIC WORKS 200 MILL AVENUE SOUTH RENTON, WASHINGTON 98055 Invoice No. : -0469 Prof. Svcs. Agreement: WW-1159-BAl-AZ Invoice Date July 31, 1992 Contract or P. 0. No. : CAG90-033 Client No. • 1159 Project Description: Engineering services rendered in connection with Boein flood plain analysis review. (WW-1159-BA1-CA) Compensation: Services of Personnel $678.96 Special Consultants and Subcontractors 201 .59 Postage 3.42 Supplies 2.40 Printing and Reproduction 12.24 Computer Services 90.00 Subtotal 988.61 Fee Due (per attached) 85.40 TOTAL AMOUNT OF THIS INVOICE $1,074.01 TERMS: Invoices due on receipt. Interest charged on past due amounts. REMITTANCE COPY i PROF. SVCS. AGREEMENT WW-1159-BA1-AZ INVOICE DATE July 31, 1992 -------------- -------------- Computation of Fixed Fee Due ---------------------------- Estimated Portion of Work Completed as of 07-31-92: 85% Portion of Total Project Fixed Fee Due as of 07-31-92 (85% of $ 854.00) $ 725.90 Less: Fixed Fee Previously Invoiced 640.50 FIXED FEE CURRENTLY BILLABLE ON THIS INVOICE . . . . . . . . . . $ 85.40 PROF. SVCS. AGREEMENT WW-1159-BAl-AZ INVOICE DATE July 31, 1992 -------------- ------------- Cumulative Amount Invoiced -------------------------- Services of Personnel $ 5,180.63 Special Consultants and Subcontractors 201.59 Postage 3.42 Supplies 2.40 Printing and Reproduction 24.24 Computer Services 105.00 Subtotal . . . . . . . . . . . . . . . . . . . . . $ 5,517.28 Fee 725.90 Total . . . . . . . . . . . . . . . . . . . . . . $ 6,243.18 R.W. BECK AND ASSOCIATES ' REPORT PC2-RG03-01 080692 01 DIRECT COST ACCOUNT LEDGER WW-1159-BA1-CA (0124) CLIENT NAME...........CITY OF RENTON PAGE...01 COST ACCOUNT NUMBER...WW-1159-BA1-CA (0124) - BOEING FLOOD PLAIN ANALYSIS REVIEW DATE...JUL 1992 COST ACCOUNT MANAGER..GISEBURT, M. WW-1159-BA1-AZ TRANSACTION CODING TRANSACTION DESCRIPTION HOURS COST COMPUTED BILL ---------------------------------- ----------------------------------- ------------- -------------------------- ------------------- TC DATE REF NO GEN LED CLAS ST DESCRIPTION GRD TITL PROJ. NUM. C/B/I APHR ACHR AMOUNT RATE AMOUNT -- ------ ------ --------- ---- -- -------------------- --- ---- ----- ------- ----- ------ ------ ------------ ------ ------------ 11 071592 WW3012 0124 7100 0011 47 REISER SM 03 0400 6.0 S S 1 8.532 11.60 69.60 22.08 132.48 11 073192 WW2409 0124 7100 0011 47 GISEBURT MS 07 3030 6.0 S S 0 23.654 32.17 193.02 61.21 367.26 11 071592 WW3039 0124 7100 0011 47 SCHAEFER RL 09 3050 2.0 S S 0 34.615 47.08 94.16 89.61 179.22 0011 EMPLOYEE LABOR...................... 14.0* 356.78* 678.96* 32 073192 094142 0124 7200 0031 HERRERA ENVIRONMENTA 191.99 201.59 0031 SPECIAL CONSULTANTS & SUBCONTRACTORS * 191.99* 201.59* 32 073192 V07158 0124 7200 0046 GO POSTAGE 3.42 3.42 0046 POSTAGE............................. * 3.42* 3.42* 32 073192 V07166 0124 7200 0048 GO COPY CENTER SUPPI 2.40 2.40 0048 SUPPLIES............................ * 2.40* 2.40* 32 073192 V07155 0124 7200 0049 GO KODAK300 12.24 12.24 0049 PRINTING AND REPRODUCTION........... * 12.24* 12.24* 32 073192 V07563 0124 7200 0063 WESTERN ENG. MICROCO 90.00 90.00 0063 MICROCOMPUTER SERVICES - IN HOUSE... * 90.00* 90.00* r . CHERRERA MA ENVIRONMENTAL CONSULTANTS Herrera Environmental Donsuhanis Inc.Suite 200 J&B Budding 1414 Dexter Avenue North Seattle,WA 98109 Phone(206)281-7604 INVOICE NUMBER: 17811.3A1 CLIENT: R.W. Beck u Assoc. 2101 4th Avenue TASK 3A1. Water Quality Problem Suite 600 Definition Seattle, WA SS121 PROJECT: Black River WC Assessment ATTN: Franchot Fenske JOB # CAG-033-90 TIME PERIOD: 6/15/92 - 7/14/92 BILLING DATE: 7/15/92 LABOR Total Rate Amount n L S Name Hours 3/hour $ �V• ' -- t Herrera O 90.00 0.00 Trial 2 89.00 178.00 Schmoyer 0 67.00 0.00 TCi. Prev. Ewing 0 66.00 0.00 __._._ _.J•_s5 L _ `i Newlin 0 61.16 0.00 1 3� �, �- Zisette C1 58.00 0.00 } "� r�''i�`'- --- --__ _.. Slaughterbeck 0 53.00 0.00 r ' Cl 1 /]r'S ( 1 "�.`1 i Ct,ughl an o 52.00 0.00 ( :-his irv.._.,_ ___ Spillane 0 52.00 0.00 Gibb1e 0 48.00 0.00 Luchessa 0 47.00 0.00 Trevathan 0 46.00 0.00 �+ Dutton a 40.00 0.00 R�=• Rp;,rov�E: '`] �� ] rl z WP a 34.00 0.00 DeForest 0.5 24.00 12.00 Other 0 0 0.00 ri r lOV3!: �% `t /(. ,- Z LABOR CHARGE: $190.00 EXPENSES Item Amount b Auto 0 miles at 0.26 per mile 0.00 ��•^.pC. ��gy__,�.�___-_ LJ."Ll. _. Telephone 1.81 Parkin0 �i Postage t+s 1,. t �tvV Reprographics j Copies copies at 4.15 C ropy 0.00 f 1WR NUMBER Supplies Meals Lodging FAX Miscellaneous Delivery 0.00 R AJ Percent Complete: 56% TOTAL EXPENSES: $1.61 0 4� 4 N Contract Total: $5,400.00 HANDLING: Billed to Date: $3,013.97 Remaining: $2,386.03 TOTAL CHARGE: $191.99 VENDOR NU.v^SER - UC.DER Cra E . � ' HERRERA ENVIRONMENTAL CONSULTANTS Herrera Environmental Consultants Inc. Suite 200 1aeouiWiog 1414 Dexter Avenue North Seattle,wmya1os Phone(una)uo1'7sn4 INVOICE NUMBER: 1710111 . 3A1 CLIENT: R. W. Beck & Assoc . 2101 4th Avenue TASK 3A1 . Water Quality Problem Suite G00 Definition SeattIe, WA 98121 PROJECT: Black River Wu Assessment ATTN: Franchot Fenske JOB # CAG-033-90 TIME PERIOD: 6/15/92 - 7/14/92 BILLING DATE:. 7/15/92 LABOR Total Rate Amount Name Hours $/hour $ Herrera 0 90. O0 0. 00 Trial 2 89. 00 178. 00 Schmoyer 0 67. 00 0. 00 Ewing 0 66. 00 0. 00 Newlin 0 61 . 16 0. 00 Zisette 0 58. 00 0. 00 Slaughterbeck 0 53. 00 0. 00 CoughIan 0 52. 00 0. 00 Spillane 0 52. 0O 0. 00 Gibble 0 48. 00 0. 00 Luchessa 0 47. 00 0. 00 Trevathan 0 46. 00 0. 00 Dutton 0 40. 00 000 WP 0 34. 00 0. 00 DeForest 0. 5 24. 00 12. 00 Other 0 0 0. 00 LABOR CHARGE: $19O. 00 EXPENSES Item Amount Auto 0 miles at 0. 26 per miIe 0. 0k Telephone 1 . 81 Parking Postage Reprographics Copies copies at 0. 15 @ copy 0. 00 Supplies Meals Lodging FAX Miscellaneous Delivery 0' 00 Percent Complete: 56% TOTAL EXPENSES: $1 . 81 Contract Total : $5, 400. 00 HANDLING: $0. 18 ` Billed to Date: $3, 013. 97 Remaining: $2, 386. 03 TOTAL CHARGE: $191 . 99 Ci of Renton PURCHASE ORDER AMOUNT FUND PROG DEPT ACCOUNT W.O. FUNCTION 200 L E.S. RENTON,WA.98055 { E 5 U 1 U C1 G U G 0 16 536 30 41 14 P. a (206)235-2618 r2'd0 ` 43C 6, 78C.00 INSTRUCTIONS n y �/ P.O.DATE: JU . : 29 1 ` 92 '71.71q,2 'P�� ✓&V - Kl;.o3/o 1. Send invoices in RIPLICATE to Purchasing Division, City of Renton. j 2. All prices are F.O.B.destination unless otherwise stated. ! 3. Indicate the Purchase Order Number on Invoice and all labels. SHIP TO: I 4. Label all shipments as specified on the Purchase Order,and enclose /3��Ja `I 1j Packing Slip with each shipment. �a7 yam, k�2 Qy/b 3S jGObr:45 Gl3o/9�. 3 � S a-. R PECK E A >SOLIATES 0�4 ;7�1 GLNvER NaTL BANK - a; 15G0 536.FS�112 ; SE VENTLFNTN ST GENVFR, 0 6C,02 QUANTITY UNIT DESCRIPTION UNIT PRICE ESTIMATED AMOUNT C (-, N F I R " I N 1; Y 1 L . 'i . BOEING CSTC PEkNiT REVIEW F L 1,0 D PLAIN � � /� 'C G 6�7 8��.0 G CHAPTER 116, LAWS OF 1965 CITY OF RENTON CERTIFICATION I, THE UNDERSIGNED DO HEREBY CERTIFY UNDER PENALTY OF PERJURY,THAT THE MATERIALS HAVE BEEN FURNISHED, THE SERVICES RENDERED! R THE LABOR PERFORMED AS DESCRIBED O HEREIN,AND THAT THE CLAIM IS A JUST, DUE AND UNPAID OBLIGATION AGAINST THE CITY OF RENTON, AND THAT I AM AUTHORIZED TO AUTHENTICATE AND CERTIFY TO SAID CLAIM. PLtvG/LLGC/PUB WKS UI ILITY SYS SIGNED: C . i { i I I AUTHORIZED BY TOTAL 7 b 0.0 0 ALPHA DP 118 9/90 E 3 s 4 p. b26 �S R.W. BECK AND ASSOCIATES t i I Fourth & Blanchard Building - 2101 Fourth Avenue - Suite 600 Seattle, WA 98121-2375 - Telephone 206/441-7500 INVOICE t CITY OF RENTON DICK ANDERSON, UTILTIY SERVICES MANAGER DEPARTMENT OF PUBLIC WORKS 200 MILL AVENUE SOUTH RENTON, WASHINGTON 98055 Invoice No. : W2-0469 t Prof. Svcs. Agreement: WW-1159-BA1-AZ Invoice Date: July 31, 1992 _ Contract or P. 0. No. : CAG90-033 Client No. : 1159 Project Description: Engineering services rendered in connection with Boeing flood plain analysis review. (WW-1159-BA1-CA) to i Compensation: Services of Personnel $678.96 Special Consultants and Subcontractors 201.59 Postage 3.42 Supplies 2.40 Printing and Reproduction 12.24 Computer Services 90.00 Subtotal 988.61 Fee Due (per attached) 85.40 TOTAL AMOUNT OF THIS INVOICE $1,074.01 CONCURRENCE V � DATE 1111cl a- N IP TIAVD T C 1992 CITY OF RENTON j Engineering Dept. I: i TERMS: Invoices due on receipt. Interest charged on past due amounts. ORIGINAL I } R.W. BECK AND ASSOCIATES 2101 Fourth Avenue,Suite 600■Seattle,Washington 98121-2375■USA Telephone(206)441-7500■Fax(206)441-4964 Consulting,(206)441-4962 Engineering Telex 4990402 BECKSEA WW-1159-BA1-CA July 23, 1992 3008 Mr. Ron Straka Acting Storm Water Utility Engineering Supervisor City of Renton 200 Mill Avenue South Renton, Washington 98055 Dear Ron: Subject: BOEING CSTC - Floodplain Analysis Review Contract No. CAG-03390 - Invoice No. 2 - June Enclosed herewith is our invoice in the amount of$3,852.35 and cost documentation for the month of June. Work during the month of June included continuation of the CSTC information review and development of the technical memorandum. If you should have any questions, please call our office. Very truly yours, R. W. BECK AND ASSOCIATES A445-�"' Michael S. Gise Project Manager MSG/cs Enclosure (MSG.042) Boston,MA■Columbus,NE■Denver,CO■Indianapolis,IN■Minneapolis,MN Nashville,TN■Orlando,FL■Phoenix,AZ■Sacramento,CA■Seattle,WA ;.f A Rtx-, cled Paper I rWoc:t RW BECK AND ASSOCIATES Fourth & Blanchard Building 2101 Fourth Avenue - Suite 600 Seattle, WA 98121-2375 Telephone 206/441-7500 INVOICE CITY OF RENTON DICK ANDERSON, UTILTIY SERVICES MANAGER DEPARTMENT OF PUBLIC WORKS 200 MILL AVENUE SOUTH RENTON, WASHINGTON 98055 Invoice No. : W2-0410 Prof. Svcs. Agreement: WW-1159-BA1-AZ Invoice Date: June 30, 1992 Contract or P. 0. No. : CAG90-033 Client No. : 1159 Project Description: Engineering services rendered in connection with Boeing flood plain analysis review. (WW-1159-BA1-CA) Compensation: Services of Personnel $3, 184.85 Printing and Reproduction 12.00 Computer Services 15.00 Subtotal 3,211.85 Fee Due (per attached) 0.50 TOTAL AMOUNT OF THIS INVOICE ,852.35 TERMS: Invoices due on receipt. Interest charged on past due amounts. REMITTANCE COPY PROF. SVCS. AGREEMENT WW-1159-BA1-AZ INVOICE DATE June 30, 1992 -------------- -------------- Computation of Fixed Fee Due ---------------------------- Estimated Portion of Work Completed as of 06-30-92: 75% Portion of Total Project Fixed Fee Due as of 06-30-92 (75% of $ 854.00) $ 640.50 Less: Fixed Fee Previously Invoiced 0.00 FIXED FEE CURRENTLY BILLABLE ON THIS INVOICE . . . . . . . . . . $ 640.50 PROF. SVCS. AGREEMENT WW-1159-BAl-AZ INVOICE DATE June 30, 1992 -------------- ------------- Cumulative Amount Invoiced -------------------------- Services of Personnel $ 4,501.67 Printing and Reproduction 12.00 Computer Services 15.00 Subtotal . . . . . . . . . . . . . . . . . . . . . $ 4,528.67 Fee 640.50 Total . . . . . . . . . . . . . . . . . . . . . . $ 5,169.17 R.W. BECK AND ASSOCIATES REPORT PC2-RG03-01 070792 01 DIRECT COST ACCOUNT LEDGER WW-1159-BA1-CA (0124) CLIENT NAME...........CITY OF RENTON PAGE...01 COST ACCOUNT NUMBER...WW-1159-BA1-CA (0124) - BOEING FLOOD PLAIN ANALYSIS REVIEW DATE...JUN 1992 COST ACCOUNT MANAGER..GISEBURT, M. WW-1159-BA1-AZ TRANSACTION CODING TRANSACTION DESCRIPTION HOURS COST COMPUTED BILL ---------------------------------- ----------------------------------- ------------- -------------------------- ------------------- TC DATE REF NO GEN LED CLAS ST DESCRIPTION GRD TITL PROJ. NUM. C/B/I APHR ACHR AMOUNT RATE AMOUNT -- ------ ------ --------- ---- -- -------------------- --- ---- ----- ------- ----- ------ ------ ------------ ------ ------------ 11 063092 WW2238 0124 7100 0011 47 OLSON AT 05 0430 1.0 S S 1 12.570 17.10 17.10 32.53 32.53 11 061592 WW2409 0124 7100 0011 47 GISEBURT MS 07 3030 17.0 S S 0 23.654 32.17 546.89 61.21 1,040.57 13 063092 WW2409 0124 7200 0011 47 GISEBURT J06064 07 3030 7.5 S S 0 23.654 241.28 61.21 459.08 11 063092 WW2409 0124 7100 0011 47 GISEBURT MS 07 3030 27.0 S S 0 23.654 32.17 868.59 61.21 1,652.67 0011 EMPLOYEE LABOR...................... 52.5* 1,673.86* 3,184.85* 32 063092 V06452 0124 7200 0049 SEATTLE TELECOPIER 12.00 12.00 0049 PRINTING AND REPRODUCTION........... * 12.00* 12.00* 32 063092 V06563 0124 7200 0063 WESTERN ENG. MICROCO 15.00 15.00 0063 MICROCOMPUTER SERVICES - IN HOUSE... * 15.00* 15.00* • . . ACCOUNT PURCHASE /�[J/1(�C ORDER AD CA FUND PROG DEPT AMOUNT, { Ity of Renton PURR AS I7 E MO. FUNCTION ..0 MILL AVE.S. RENTON,WA.98055 - 'Zt S5 I "01 000000 16 53 b 30 41 148 (206)235-2618 +'(Z90 5 43 0 6976C.00 INSTRUCTIONS P.O.DATE: Jt)'_. �, I 9 7171q,)� -P jot 9&V- h/.2-o3/0 8� s 1. Send invoices in TRIPLICATE to Purchasing Division,City of Renton. /�- i 2. All prices are F.O.B.destination unless otherwise stated. i 3. Indicate the Purchase Order Number on Invoice and all labels. SHIP TO: j r' 1! 4. Label all shipments as specified on the Purchase Order,and enclose � �� �YVI/. k/2.Qy/b `I 3S Packing Slip with each shipment. 'j{ Gl3o/9a 3�' Sa. i0U8`i45 I >/ 610. 83 R P,' BECK L ASSOCIATES DENvER NATL BANK — R1y00 112 ', SEVENTEFNTH ST DENVER, 0 80�02 f QUANTITY UNIT DESCRIPTION UNIT PRICE ESTIMATED AMOUNT C C N F I R M I N G Y I I I 1 L .S . BOEING CSTC PERMIT REVIEW 69780 ,00 69780.00 CHAPTER 116, LAWS oF��ss5= F L G O U PLAIN CITY OF RENTON CERTIFIOATI&W I i I, THE UNDERSIGNED DO HEREBY CERTIFY UNDER PENALTY OF PERJURY,THAT THE MATERIALS HAVE BEEN FURNISHED, THE SERVICES RENDERED OR THE LABOR ` PERFORMED AS DESCRIBED HEREIN,AND THAT THE CLAIM IS A JUST, DUE AND UNPAID OBLIGATION AGAINST THE CITY OF RENTON, AND THAT I AM AUTHORIZED TO AUTHENTICATE AND CERTIFY TO SAID CLAIM. PLNG/BLDG/PUB WKS UTILITY SYS SIGNED: C • Ia 1 AUTHORIZED BY TOTAL 69760.00 ALPHA DP 118 9/90 A R.W. BECK AND ASSOCIATES Fourth & Blanchard Building - 2101 Fourth Avenue - Suite 600 Seattle, WA 98121-2375 - Telephone 206/441-7500 INVOICE CITY OF RENTON DICK ANDERSON, UTILTIY SERVICES MANAGER DEPARTMENT OF PUBLIC WORKS 200 MILL AVENUE SOUTH RENTON, WASHINGTON 98055 Invoice No.: W2-0410 Prof. Svcs. Agreement: WW-1159-BA1-AZ Invoice Date: June 30, 1992 Contract or P. 0. No.: CAG90-033 Client No. : 1159 Project Description: , Engineering services rendered in connection with Boeing flood j plain analysis review. (WW-1159-BA1 CA)'�t--" ,RAi;,a F . � 1 ' y r1 Compensation: HL 211. 1992 C1;�` OFFt�T��` Services of Personnel $3,184.85 Printing and Reproduction Eh I":eerin� [)< r . 12.00 Computer Services 15.00 Subtotal 3,211.85 Fee Due (per attached) 640.50 TOTAL AMOUNT OF THIS INVOICE $3,852.35 A& CONCURRENCE DATE 1 "i NAME INI IAL/D T' TERMS: Invoices due on receipt. Interest charged on past due amounts. ORIGINAL A R.W. BECK AND ASSOCIATES 2101 Fourth Avenue,Suite 600■Seattle,Washington 98121-2375■USA Telephone(206)441.7500■Fax(206)441.4964 Consulting,(206)441-4962 Engineering Telex 4990402 BECKSEA WW-1159-BA1-CA June 22, 1992 3008 Mr. Ron Straka, Project Manager T1E Actin Surface Water Utility Supervisor ` } g Y P 3 City of Renton 200 Mill Avenue South Renton, Washington 98055 `' il i 1 L Ci TY CIF PENTOi Dear Ron: �,- Er,gineering Subject: City of Renton Boeing Flood Plain Analysis Review Contract No. CAG-03390 - Invoice No. 1 - May Enclosed herewith is our invoice in the amount of$1,316.82 and cost documentation for the month of May. In addition, we have enclosed a cost summary of the cost total to date. Work for the month of May included an initial review of CSTC stormwater plan, and checking the compensatory storage volumes. If you should have any questions, please call our office. Very truly yours, R. W. BECK AND ASSOCIATES 44114"- e� Michael S. Giseb t Project Manager MSG:ato Enclosure (MSO.051) Boston,MA■Columbus,NE■Denver,CO■Indianapolis,IN■Minneapolis,MN Nashville,TN■Orlando,FL■Phoenix,AZ■Sacramento,CA■Seattle,WA A Recycled Paper Pnxhu:t City of Renton Boeing CSTC Flood Plain Analysis Review Budget Status Through Month of May File Name:Boeing$.wk3 Task X Labor Expense Total Current %budget Current %budget Current %budget Budget Budget Budget Labor expended Expenses expended Total expended labor Expenses total Phase 1 Flood Plain Analysis $6,550 $230 $6,780 $1,317 20% $0 0% $1,317 19% Phase 2 Modify FEQ Model(not approved) $3,543 250 $3,793 $0 0% $0 0% $0 0% Totals $10,093 $480 $11,890 $1,317 $0 $0 $0 $1,317 11% R.W. BECK AND ASSOCIATES Fourth & Blanchard Building - 2101 Fourth Avenue - Suite 600 Seattle, WA 98121-2375 - Telephone 206/441-7500 INVOICE CITY OF RENTON DICK ANDERSON, UTILTIY SERVICES MANAGER DEPARTMENT OF PUBLIC WORKS 200 MILL AVENUE SOUTH RENTON, WASHINGTON 98055 Invoice No. : W2-0310 Prof. Svcs. Agreement: WW-1159-BA1-AZ Invoice Date: May 31, 1992 Contract or P. 0. No. : CAG90-033 Client No. : 1159 Project Description: Engineering services rendered in connection with Boeing flood plain analysis review. (WW-1159-BA1-CA) ; Compensation: Services of Personnel $1,316.82 TOTAL AMOUNT OF THIS INV/CE $1,316.82 TERMS: Invoices due on receipt. Interest charged on past due amounts. REMITTANCE COPY r J PROF. SVCS. AGREEMENT WW-1159-BA1-AZ INVOICE DATE May 31, 1992 -------------- ------------ Cumulative Amount Invoiced -------------------------- Services of Personnel $ 1,316.82 R.U. BECK AND ASSOCIATES " REPORT PC2-RG03-01 060892 01 DIRECT COST ACCOUNT LEDGER WW-1159-BA1-CA (0124) CLIENT NAME...........CITY OF RENTON PAGE...01 COST ACCOUNT NUMBER...WW-1159-BA1-CA (0124) - BOEING FLOOD PLAIN ANALYSIS REVIEW DATE...MAY 1992 COST ACCOUNT MANAGER..GISEBURT, M. WW-1159-SAl-AZ TRANSACTION CODING TRANSACTION DESCRIPTION HOURS COST COMPUTED BILL ---------------------------------- ----------------------------------- ------------- -------------------------- ------------------- TC DATE REF NO GEN LED CLAS ST DESCRIPTION GRD TITL PROJ. NUM. C/B/I APHR ACHR AMOUNT RATE AMOUNT -- ------ ------ --------- ---- -- -------------------- --- ---- ----- ------- ----- ------ ------ ------------ ------ ------------ 11 053192 WW2702 0124 7100 0011 47 WEBER MB 06 3020 15.0 S S 0 18.173 24.72 370.80 47.03 705.45 11 053192 WW2409 0124 7100 0011 47 GISEBURT MS 07 3030 3.5 S S 0 23.654 32.17 112.60 61.21 214.24 11 053192 WW2409 0124 7100 0011 47 GISEBURT MS 07 3030 6.0 S S 0 23.654 32.17 193.02 61.21 367.26 11 053192 WW1552 0124 7100 0011 47 BALDWIN LB 08 1240 0.5 S S 0 23.077 31.38 15.69 59.74 29.87 0011 EMPLOYEE LABOR...................... 25.0* 692.11* 1,316.82* CITY OF RENTON MEMORANDUM DATE: May 1, 1992 TO: Lenora Blauman FROM: Ron Straka SUBJECT: R. W. BECK REVIEW OF THE BOEING CSTC PROJECT FLOOD PLAIN ANALYSIS Attached is a copy of the proposed budget sheet for the flood plain analysis review of the Boeing Customer Service Center Training Center (CSTC) by R. W. Beck and Associates. The Utility recommends that the work be authorized. The Phase II work (Task 2a4) will only be authorizated if it is identified as being needed as a result of the initial review of the CSTC flood plain analysis. The review of the Boeing project flood plain analysis is needed to ensure that the project will comply with the City flood plain regulations and surface water management codes. The review will also ensure that the project will not change the results of the Surface Water Utility's East Side Green River Watershed (ESGRW) Plan hydrologic and hydraulic analysis. The work was approved by Council as part of our consultant contract (CAG-90-033) Amendment No. 4. The total cost of option No. 2 is $11,198 with the Phase I work costing $6,780. The'authorization of this task was subject to all work being funded by the Boeing Company. The task scope of work will benefit Boeing in the future, since it will document the differences between the FEMA flood plain elevation and the simulated flood plain elevation as established by the ESGRW Plan hydrologic and hydraulic modeling. This will also ensure that the hydraulic models which are being utilized to analyze potential flood control alternatives is up-to-date and accurately reflects the current hydrology and hydraulics in the basin. Please authorize us to utilize the Boeing CSTC work order (W.O.#87290) to establish a P.O. for completion of all work associated with the task. There is a possibility that the Phase II work will not be required. This review is important to both the Boeing CSTC project surface water management plan approval and the ESGRW Plan. If you have any questions regarding this subject, please contact me at X-5547. D:92-329:R.JS:ps CC: Priscilla Pierce Attachment CITY OFRENTON C\j EASTSIDE GREEN RIVER WATEERSEI--D PLAN 0 May 1, 1992 CONTRACT AMENDMENT NUMBER 4 - TASK 10 -- BOEING REVIEW Phase I(with qualitative analysis of Boeing impacts on ESG\VP modeling) R.W.BECK AND ASSOCIATES RWB RWB R\VB Subconsuliant i RS MSG MW WP LB SEC total total (includes 5°'o mirk—up) 7 OTn C\j Task No. Description $103 S70 $54 S43 S69 $.'t2 hours expenses mst LKA COS rn ' X Boeing flood plain plan analysis review Co CD 1. meetings(3 to 5 hr each) 15 5 20 S30 $1,356 j N 2. Flood Plain AnAtysis review 2al. Review Boeing Materiats 6 10 161 $962 S96 O 25a Discuw FEMA Versus ESGR\VP results 0 81 $563 j S5( z W. Asuxs the propoxxl CSTC impacts on ESGRW Plan 1 6 7 $394 S3i x 2bl. Flood PlainArtalyslsReview 2 20 22 S1,221 S1,L �' I 3.ReviewTocbnieal Memorandum 2 2 12 h 2 24 S11X) S1,418 1.41 4. Invoicing/Contaci Admin.(2 months) 8 2 2 12 S1tX) Sft65 i total 2 42 53 6 2 4 109 S230 56,76(I SO SR iF r� l - t� 2 Phase 2(Optional)(modiMnb future conditions FEO modei to reiiect CSTC-development) C� o R,W.BECK AND ASSOCIATES R1YB. f2WB RWE3 JUI3CONSULTANT cn RS MSG MNV \VP LB SEC total total j TOTY r� ¢ Ta*No. Description $103 $70 $54 $43 S69 S32 hour expenses cost LKA co x t v 2a4, Modify Future condition FEO model&results �m t Modify model 1 6 7 5394 $625 $1,) New connections to Springbrook 1 6 7 S394 j 53 281 tz Dis dtribute hydro aphs 1 4 5 S '1 Distribute wetland storage 1 6 7 S394. S3 Model Runs(assume all storms) 2 14 16 150 Sl,(A7; S U) Document changes to model in next report 4 4 2 10 SSW! SS Ioicing/ContaciAdmin,(I onths) 6 2 1 9; $1W S692 j w m S6 total 0 16 40 2 2 1 611 S250 $3,793 S625I S414 t� N CT) I Q 7Label Ity of RentonPURCHASE ORDER FUND PROG DEPT ACCOUNT W-O. FUNCTION AMOUNT MILL AVE.S. • RENTON,WA.98055 ` '(206)235-2618INSTRUCTIONS P.O.DATE: c / "� " � K/� d3/Q oices in TRIPLICATE to Purchasing Division, City of Renton. are F.O.B.destination unless otherwise stated. 3 I gahe Purchase Order Number on Invoice and all labels. SHIP TO: shipments as specified on the Purchase Order,and encloseSlip with each shipment. P PECK t. AISO(:IATLS TL BANK OU 112 : SFvFNTL-FNTN ST GEIYFR, 0 80,,02 QUANTITY UNIT DESCRIPTION UNIT PRICE ESTIMATED AMOUNT C C N F I P I N <; r 1 L .` b0LI,iG CSTIC PFkmiT PEVIEw bt7�U.U0 C.id0.0C? C CHAPTER116, :AWSOF1965 ' F L U('D P L iz I tN CITY OF RENTONERTIFICATION I, THE UNDERSIGNED DO HEREBY CERTIFY UNDER PENALTY OF PERJURY, THAT THE MATERIALS HAVE BEEN FURNISHED, THE SERVICES RENDERED OR THE LABOR PERFORMED AS DESCRIBED HEREIN,AND THAT THE CLAIM IS A JUST, DUE AND UNPAID OBLIGATION AGAINST THE CITY OF RENTON, AND THAT I AM AUTHORIZED TO AUTHENTICATE AND CERTIFY TO SAID CLAIM. (iti PLK'G/bLGG/PUB h'KS UTILITY SYS SIGNED: i i i i AUTHORIZED BY TOTAL 6 ?b 0.0 U ALPHA DP 118 9190 C�1 R W BECK AND ASSOCIATES Fourth & Blanchard Building 2101 Fourth Avenue - Suite 600 Seattle, WA 98121-2375 Telephone 206/441-7500 INVOICE CITY OF RENTON DICK ANDERSON, UTILTIY SERVICES MANAGER DEPARTMENT OF PUBLIC WORKS 200 MILL AVENUE SOUTH RENTON, WASHINGTON 98055 Invoice No. : W2-0310 Prof. Svcs. Agreement: WW-1159-BAl-AZ Invoice Date: May 31, 1992 Contract or P. 0. No. : CAG90-033 Client No. : 1159 Project Description: Engineering services rendered in connection with Boeing flood plain analysis review. (WW-1159-BA1-CA) Compensation: Services of Personnel $1,316.82 TOTAL AMOUNT OF THIS INVOICE $1,316.82 CC;.'CURRENCE , i � � TE NA E ! TJAVD TE A/o. 'q /GvU UJp S Sri ; 70.�•� f D o � r TERMS: Invoices due on receipt. Interest charged on r f^�/iLc%it r 7 /"" VAL