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HomeMy WebLinkAboutCC AG PKT 2003-03-24 #Q AGENDA REPORT 4,1 (^ DATE: March 24, 2003 ✓ 1 0 e, TO: Honorable Mayor and City Council 4/ev p.„ THRU: John B. Bahorski, City Manager FROM: Doug Danes, P.E., Director of Public Works / City Engineer SUBJECT: DECLARATION OF EMERGENCY, URGENT NECESSITY & NUISANCE AT SUNSET AQUATIC PARK - SEWER LINE LEAK SUMMARY OF REQUEST: 1) The proposed City Council action ratifies the City Manager's decision to take action to abate the threat to public health created by the sewer leak at Sunset Aquatic Park. 2) If approved, the Council will find that the sewer leak, and potential for further leaks, constitutes: an emergency per City Charter Section 107; a matter of urgent necessity as used in Charter Section 1010; and a nuisance per City Code Sections 14 -1 and 14 -10. 3) Staff recommends that per the Charter and Code, the Council adopt Resolution for a budget amendment for up to $600,000 to abate the nuisance; and authorize the City Manager to execute the contracts necessary to abate the nuisance not to exceed $600,000. BACKGROUND: On the afternoon of March 12, 2003, a Public Works Crew Member noticed a small sink- hole (approximately 3' diameter) developing approximately 75' from one of the two sewer pump stations that serve the County of Orange Sunset Aquatic Park Facility. Upon further investigation the sewer line was dye tested and small amounts of the dye were noted slowly emanating up to the surface at the sink -hole. No dye was noticed elsewhere in the bay. It was then concluded that there was a leak somewhere in the 6" diameter submerged cast iron sewer force main that crosses under Anaheim Bay to Pacific Coast Highway. The pipe is submerged under 15' to 25' in the ground underwater. The actual cause of the incident cannot yet be determined although it is assumed to be a leak in the pipe. The sewer line is not accessible by sewer cameras due to the profile of the pipe and the sharp angle in which the pipe drops to meet the design depth of the pipe to cross the Anaheim Bay. Upon determining that there was a sewer leak into a water body, Public Works immediately shut off the water at all Aquatic Park meter locations including the restrooms and Harbor Patrol Headquarters. Further, the County personnel at the site were notified of the action. This was performed to prevent any more sewage from entering the bay. The Department then notified by phone the Santa Ana Regional Water Quality Control Board and the Orange County Health Care Agency, per the requirements of the • • AGENDA ITEM a waste discharge permit. The Department has placed above ground holding tanks at the first pump station in the parking lot to temporarily collect the sewage on site. These tanks are pumped into a truck and transported it to a location where the waste will be deposited into the sewer system. This method is a temporary method and may cost up to $3,000 a week until a permanent solution is completed to abate the nuisance. If the interim action was not taken, the pumps would have continued to run and sewage would leak into Anaheim Bay causing an immediate risk to the Bay and threatening a sensitive habitat area. Due to the age of the pipe, it is foreseeable that other leaks will develop. The uncertain condition of the pipe constitutes a public nuisance per se. The discharge of sewer waste into the water and a sensitive habitat, and the threat of future discharges, each constitute a public nuisance that requires immediate attention. In the absence of the permanent solution proposed, coastal uses such as fishing and boating will have to be terminated or severely restricted. The correct solution needs to be implemented so that the Bay and its precious resources will no longer be threatened. The • recommended action is the least environmentally damaging alternative. Repairing the pipe in its present location within Anaheim Bay would require dredging approximately a 60' to 90' wide area to uncover the 20 +' deep pipe and sending underwater divers into the bay to locate the leak. This is not feasible for a number of reasons, including the possible adverse environmental impact to the area. Slip lining was initially examined but was ruled out by the City's consulting engineers due to the alignment and reach of the pipe. Even if possible, this would still leave the pipe within the bay, which, in its current condition, constitutes a nuisance. Alternatively, the only other solution would be to permanently close the park facility and/or not provide sewer service. The original sewer system was constructed in 1968 over 30 years ago. Improvements to the Aquatic Park sewer system had been identified for implementation in FY 2008/2009 per the City Council adopted 1999 Sewer Master Plan. As a pro- active alternative the City has been working with the City of Huntington Beach over the past year to explore the possibility of Huntington Beach accepting the flows from Aquatic Park. New force mains would be installed and connected with the Huntington Beach's sewer system. This would mean that flows would be pumped in the opposite direction easterly within the street right of way of Edinger Avenue. This alternative would have the least potential adverse impact upon the environment. The City has applied for Orange County Sanitation District Cooperative Grant Program and Prop 12, 13, & 40 Grants for the proposed project but has not been awarded any funds. A letter was sent to Coastal Commission on Friday, March 14, 2003 waiving Emergency Permit Requirements Section. 30611, Public Resources Code. Public Works intends on implementing a project as quickly as possible. Staff met with the City of Huntington Beach's City Engineer, Maintenance Operation Manager, on Tuesday, March 18, 2003 to discuss the concept plan. There were some concerns about capacity limitations within the Huntington Beach system but flow studies conducted by Seal Beach indicates that the sewer system will be able to accommodate flows from Aquatic Park as long as some • •• r . project safeguards within the station are implemented to prevent flows during their peak usage. Additionally, an agreement would need to be executed between both Cities to memorialize the use of the Huntington Beach sewer system to transport the waste. The nuisance will be abated using the following course of action: 1. Obtain Encroachment Permits: Submit and obtain an encroachment permit from Huntington Beach for immediate installation of two 2" diameter pipes easterly from the park along Edinger Avenue to the manhole located at the intersection of Edinger Avenue and Trinidad Avenue. This will also require an encroachment permit from Orange County Public Facilities and Resources Department to allow the sewer line to be installed over the Edinger Bridge. 2. Construct Sewer Line: Upon issuance of permits, begin installation of these pipes as describe above. 3. Design of New Pump Station: While steps 1 & 2 are being implemented, final design for a new pump station would begin. 4. Sewer Service Agreement: Adoption or an agreement by both Seal Beach and Huntington Beach City Councils to accept Seal Beach wastewater generated by Sunset Aquatic Park. It is anticipated that the sewer service agreement will be placed on the next available council meeting. 5. Obtain Easements: Survey the pipe constructed within Huntington Beach right of way and obtains easements for the improvements. 6. Construction of New Pump Station: Construct the proposed facility as described in the attached Sunset Aquatic Park Pump Station Concept Study (Figure 6). 7. Final Connection: After construction is completed and agreements are executed, Public Works will make the final connection to Huntington Beach's sewer system and remove temporary storage tank. The order of these steps is almost completely reversed that what would occur in a normal project due to the severity of the situation. Every week this situation is not corrected, the City will incur a financial drain to the sewer capital fund. Additionally, the interim method of pumping the sewer flow is not intended for a long -term solution, due to the environmental risks, financial costs and labor demands. If a potential sewer overflow were to occur during this temporary fix usage of water in the park would need to be severely restricted affecting coastal recreation and boating .uses. As it stands now, the temporary solution restricts the services provided to users and visitors to the aquatic park. No project is without risk. One potential risk is that Huntington Beach could refuse to accept the flows once the improvements are completed. The probability of this occurrence seems low due to the nature of the situation and the cooperation to date that • • has been received from their staff. Staff believes that waiting until an agreement is executed between the cities would result in a loss of valuable design and construction time and would incur further expenditures in maintaining the interim storage and pump out condition. Upon considering the impacts upon the environment, this facility is best served by a connection with Huntington Beach rather than repairing a line within the bay and pumping northerly along Pacific Coast Highway. An additional potential risk is that another agency could delay the permitting process or take jurisdiction. Due to the gravity of the event and the proposed solution, it is anticipated that all agencies will lend support rather than cause delays. Once again, any delays will adversely affect the users and visitors to the park. The proposed project to abate the nuisance makes environmental, engineering and financial sense. In addition to the steps above, it is recommended that the City make a declaration that the sewer line constitutes a public nuisance. Pursuant to the Code of the City of Seal Beach, Section 14 -1, a public nuisance is defined as follows: "Public nuisance" shall mean anything which is injurious to health, or is indecent or offensive to the senses, or is an obstruction to the free use of property, so as to interfere with the comfortable enjoyment of life or property by a neighborhood or by any considerable number of persons in the City irrespective of whether the annoyance or damage inflicted upon individuals is unequal. The California Coastal Act contains an exemption from the requirements of obtaining a Coastal Permit when necessary to abate a public nuisance: PRC Section 30005. No provision of this division is a limitation on any of the following: (a) Except as otherwise limited by state law, on the power of a city or county or city and county to adopt and enforce additional regulations, not in conflict with this act, imposing further conditions, restrictions, or limitations with respect to any land or water use or other activity which might adversely affect the resources of the coastal zone. (b) On the power of any city or county or city and county to declare, prohibit, and abate nuisances. FISCAL IMPACT: Funds are available within the cash balance of the sewer fund. Funding originally for this project was budgeted in later fiscal years upon issuance of the second sewer certificate of participation (COP) but instead will be used from cash balance. Line replacement projects programmed for FY 03/04, within the Council approved Capital Improvement Program, will be programmed in later years to accommodate delivery of this project. (50041 CPE Line Replacement, $475,000, 49813 Old Town Line Replacement (Alley), • $250,000, and 50092, 8 Street Line Replacement $181,000.) This will not only preserve cash balance should another emergency occur in the sewer system but also is necessary due to limited Public Works resources for delivery of projects. RECOMMENDATION: It is recommended that City Council: 1) Ratify the City Manager's decision to take action to abate the threat to public health created by the sewer leak at Sunset Aquatic Park. 2) Declare and find that the sewer leak, and potential for further leaks, constitutes: an emergency per City Charter Section 107; a matter of urgent necessity as used in Charter Section 1010; and a nuisance per City Code Sections 14 -1 and 14 -10. 3) Adopt Resolution for a budget amendment for up to $600,000 to abate the nuisance; and authorize the City Manager to execute the contracts necessary to abate the nuisance not to exceed $600,000. 1111111. Doug Dancs, P.E., i tcer or of Public Works /City Engineer , 41______, NO r : , 1 2 OVE D : Jo :. Bahorski, City Manager • • Attachment 1 Concept Study Sunset Aquatic Park Pump Station Sunset Aquatic Park Pump Station Concept Study ' r ` +rA .3l I yF'. ,fir''-'• _ •. - ' a -,~ _ 'y' «,h - ' _ n S f - i.�9 n��, r!-,. "1Y ai .` .? - ..:- -;. ,ice a '`4..,J• ''•: *t. :�� ;d;r. r.,' 'Y r,. : f,,,s.cv •, - ;' �, , S., `i-F ; �r J: . ' #.j, •,.' ;� Y i : � .s. "i a`' s'�• :.'�i ' sS ? rt �•: ; , • : j' r. "! ` s . ,. ^ f : Y ri'1 ., - i -b• -'n .�, .i.'. k. �`V • .far E - We ti - �•�� . ;, r ^ex, "z:?' `.r, "- y ,- - •. - •r• -' ' Z ; • } - S;jr'': ,y�strrr . 1, x�« s ". ! *1 v • -�,- %:, . ye. _ , 'i l - .t"'- V • 'j', �Mrti• ,.. - , i. �_ .'-�'y «r. +°. ' f. n J "; -..°» r;: "•• ::., r •� r`y?.. °,i:� ' :A.,*..',2e. , rt.v i • N .j,,. •rn�t. -; 'fi r- . ,S _' :-L7.,- -;'�c0 n� /s`'y «' wig - '.3% - r . - .,"j' : {; - •a - •i. = ' . , • ,.' L °... ; . ii 19- .E :. ' +: `'��' 4' r: • i s �rf: - } v .t n n - ! �. F L •,,�FlYrlt. •3, ark. „ 'r t�" . ' ... ri' C., M' ,,., -- _ " ! -r y . ,�( , m „ �• ja •'Y `°w� 1'd '""fi't x 3a P r . . c,, , w �F3 y e r '••,: `. - - : 4 t• ` 1 ,.. l k"� � ' :. rte-r ,a ti . . " '-•rig- ,��.., ` a I"' s.. 4 �,, � y yi '� i `. "- w >a , 'ark . r* *— �� uH�w -'' - Submitted to: }'•. City of_ Seal Beach •• ; - Public Works Department Seal Beach, California ` - Submitted by: :::x: AKM Consulting Engineers . � G pitPORg4.: - e ,.. •. :r`r��,, March 17, 2003 ,..tii; ,,.� C Dti► CITY OF SEAL BEACH SUNSET AQUATIC PARK PUMP STATION CONCEPT STUDY Submitted to City of Seal Beach Public Works Department Seal Beach, California Submitted by • AKM Consulting Engineers 101 Pacifica, Suite 150 Irvine, California 92618 (949) 753 -7333 March 17, 2003 TABLE OF CONTENTS Section Page 1.0 Introduction 1 2.0 Sunset Aquatic Park Pumping System 2 2.1 Background 2 2.2 Flows 4 • 3.0 City of Huntington Beach Sewer System and Potential Connection Locations 5 3.1 Existing System - Flows and Capacity 7 4.0 Pumping Alternatives 8 4.1 Grinder Pump System 8 4.2 4 -Inch Pump and Forcemain 9 5.0 Alternative Comparison and Costs 14 6.0 Existing Bridge Crossing 15 7.0 Summary 16 LIST OF FIGURES Figure No. - Page 1 Existing Aquatic Park Pumping System 3 2 Existing City of Huntington Beach Huntington Harbor Sewer System 6 3 Grinder Pump 8 4 Grinder Pump Station Site Plan 10 5 Grinder Pump Station 11 6 4 -Inch Vortex Pump Station Site Plan 12 7 4 -Inch Vortex Pump Station 13 LIST OF PHOTOGRAPHS Photo No. Page 1 Pump Station No. 1 — Looking west 2 • 2 Pump Station No. 1 — Looking north 2 3 Alignment for Sewer Connection at Bravata Drive - - 5 4 Alignment Corridor for Sewer Connection at Bravata Drive 5 5 Sewer Manhole at Bravata Drive 5 6 Point of Connection — City of Huntington Beach Manhole 7 7 Point of Connection — City of Huntington Beach Manhole 7 8 Edinger Avenue Bridge — View looking east 15 9 Edinger Avenue Bridge — View beneath 15 10 Edinger Avenue Bridge — South side of bridge 15 11 Edinger Avenue Bridge — North side of bridge 15 APPENDIX • Grinder Pump Station Cost Estimate • 4 -Inch Vortex Pump Station Cost Estimate • City of Huntington Beach Sewer Flow Monitoring Data • Aquatic Park Pump Station Flow Monitoring Data CITY OF SEAL BEACH i SUNSET AQUATIC PARK PUMP STATION CONCEPT STUDY KlSeal BeachlAquatic ParklAquatic Park Alternatives Preliminary (3 -17 -03) SECTION 1.0 INTRODUCTION The City of Seal Beach provides water and sewer service to the Sunset Aquatic Park, which is located just west of Huntington Harbor in the City of Huntington Beach. Because the City maintains no water or sewer facilities in the vicinity of the park, pipelines were extended from the Old Town area, in Pacific Coast Highway, to Anaheim Bay, where they crossed under the bay to the park. The piping facilities under the bay. have long been of concern to the City, and in particular, the = sewer forcemains which were constructed. The pipes under the bay are difficult to monitor, and ' require extensive effort to repair in an environmentally sensitive area.. The forcemain has in fact failed twice (1985 and 2003), and its current overall condition is not known. To circumvent a potential environmental disaster, the City has requested that alternatives for potentially redirecting flows to the City of Huntington Beach's sewer system in Huntington Harbor be investigated. . This concept study has been prepared in response to that request. • • 1 CITY OF SEAL BEACH AQUATIC PARK PUMP STATION ALTERNATIVES Meal BeachlAquatic ParklAquatic Park Alternatives Preliminary (3 -17 -03) SECTION 2.0 SUNSET AQUATIC PARK PUMPING SYSTEM 2.1 Background Located in Anaheim Bay, within the corporate boundaries of Seal Beach, but segregated from the main City area by the Wildlife Refuge and Naval Weapons Station, is the Sunset Aquatic Park. The 63 -acre park was acquired by the County in 1963 from the Navy and provides boat slips, boat ramps and picnic areas to the public. Sewer service is provided through a small collection system owned by the County, and two submersible pumping stations owned and operated by the City. Park facilities being served by the sewer system consist of five restroom buildings, the Harbor Patrol building, a dockside cafe, the - marina management offices, and the Sunset Aquatic Shipyard. Aquatic Park Pump Station No. 1 was constructed in 1968 and is located within a landscaped area of the park's parking lot. It is a small packaged type submersible station• installed within a concrete vault. The station originally contained two submersible pumps mounted in a small steel wet well with shafting to a dry well motor mounted above. In 1984, the pump and motor arrangement was replaced with two submersible pumps and motors. The electrical control panel was also replaced at that time The facility collects all of the flows generated at the park and pumps them under a channel through a 4 -inch force main, and an 8 -inch gravity line, to Aquatic Park Pump Station No. 2. This station is located on an island in Anaheim Bay, and is identical to Pump Station No. 1, in all respects except for pump size. It was also retrofitted in 1984 with a new control panel and pumps. • From Pump Station No. 2, sewage is pumped through a 6 -inch force main under Anaheim Bay, to Pacific Coast Highway and then Seal Beach Boulevard to its discharge point into the City's collection system at Beryl Cove Way and Marlin Avenue in the Marina Hill South area. From there, it flows by gravity to Pump Station No. 35, which lifts the flows into the OCSD system for treatment and disposal. The Aquatic Park System is shown on Figure 1. Photographs 1 and 2 show Pump Station No. -1. y ► / Y fr C '� � 4 1 p�,{ .,� I'. .� .RI !^ � ,. r 11 • : s s e •':` F a« r- �, : ro r J 3 ""'.� t ' ii aG. ILa " Ss f r. u� F '. } r.Y F;� ice' .,,r,h7, Z,,�r{�';y'�"; �4 r.*"``1 ';N`"'. i ��✓ i 7 /F t „1 � �, iiC',+,j 4 ^i '. �Y •`2?' , r !t:. oSr, 1L-4r > 1✓i} a -'S a.zaszS. Photo 1. Pump Station No. 1 - Looking west Photo 2. 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EI ti 1� w 7 1 ( f + � -:. r � � � i t F - �L 4,4 Y t -K+ a { y • h a r r 'c':',..-.=-:. � _ � � l�p k� (� f a �� r.. .t: - 1't✓"- 1 f ��� � '�• J ',,;.,,.1=',''' ~ X + x Y ' 'w M -' �A' ' ,y+ al- 1 ! r f a x _ . i i r . ^s t" - `Z� L IG � °r� t �, , i .a 1 k + fGa i p,.... � ' ' , � n Fyl.., i� .., �, � - � G u ... �Y; �f` - y i V , '$ �` '� f �:� 1 � 5 1�� � "T ,tti ; ,d'- � } .. sa y' �\ ?��r y �:- .' �f .. k t1*1. t l t :t��' . 1 �� s r - �n "t . .1 _ � • Both pump stations are in extremely poor condition and are difficult to maintain. In 1985, the Pump Station No. 2 forcemain under Anaheim Bay failed. Repairs were difficult and required 15 feet deep excavations to find and repair the leak. On March 12, 2003, the Pump Station No. 2 forcemain under the Bay again failed. As a result, the Aquatic Park Pumping and Forcemain System have been taken out of service. Currently, sewage is being pumped into a 1,500 gallon holding tank located adjacent to Pump Station No. 1, and hauled daily by truck to disposal. 2.2 Flows In September of 2002, AKM Consulting Engineers performed a field study to determine the influent flows to Pump Station No. 1. The study was conducted on Monday, September 23, 2002, between the hours of 6:00 a.m. and 6:00 p.m. An AKM representative at the site timed filling and pump down cycles, and recorded wet well levels through the 12 -hour period. The results of the study were as follows: Average Influent Flow 2.7 gpm - Peak Influent Flow 10.3 gpm Total Flow (6:00 a.m. — 5:45 p.m.) 1,840 gallons Pump 1 Pumping Rate 150 gpm Pump 2 Pumping Rate 145 gpm To confirm the field study, influent flow was also estimated from recorded pump running hours over a 1 -year period. The result was an average flow of 8.2 gpm. Applying the peaking factor from the 1 -day flow study of 3.8 to the average flow calculated from pump running hours yields a peak flow of 31 gpm. It is recommended that any future pumping facility be designed to provide a minimum pumping capacity of 30 gpm. Raw data from the flow study is included in the Appendix of this study. - CITY OF SEAL BEACH 4 SUNSET AQUATIC PARK PUMP STATION - CONCEPT STUDY • KlSeal BeachlAquahc ParklAquatic Park Alternatives Preliminary (3- 17-03) SECTION 3.0 ' CITY OF HUNTINGTON BEACH SEWER SYSTEM AND POTENTIAL CONNECTION LOCATION The existing City of Huntington Beach Sewer System in the vicinity of Sunset Aquatic Park is shown on Figure 2. The nearest potential connection points to the system are located at Contender Lane and Bravata Drive, in a private residential area (approximately 2,700 LF from the Aquatic Park Pump Station); or within public right -of -way in Edinger Avenue, at the intersection of Trinidad Lane . (approximately 3,800 LF from the Aquatic Park Pump System). The sewer at Bravata Drive is 8 -inch in size and will require an easement from the Homeowners Association, in addition to City and County encroachment permits, and a connection agreement _ with the City of Huntington Beach. A connection in Edinger Avenue to the existing 10 -inch sewer is - in public right -of -way and does not require an easement to be secured. Photographs 3, 4 and 5 show the connection location at Bravata Drive. • r < -.I ,< I '. } s t 4 ? 4 Wo o .., f A . . tea' _ r .- .,"t ".I ( i r r ,- a , y 2 �. r- Y , JJJ - ' Photo 3. Alignment for sewer connection at Bravata Photo 4. Alignment corridor for sewer connection at Drive (view from Edinger Avenue) Bravata Drive (view from Bravata Drive) �.�. ' / 1 -..- .:1d_, i , Y kk 7 I1 ■ L r _ Photo 5. Sewer Manhole at Bravata Drive CITY OF SEAL BEACH 5 SUNSET AQUATIC PARK PUMP STATION CONCEPT STUDY KlSeal Beachl.quatic ParklAquahc Park Alternatives Preliminary (3 -17 -03) , _ . .. r . • .. 1 i •P• ! ; rt i ; .11r, ' -0 sk i illik. , . I, I I I t 7 . . ILL ilt '11 lir • NI 41 , l at `I° 3IPf1MMOO ' - I C r J fre 4 -.1 f i, 7 Z " ...I - -E U . 441411 __......_ T�- � , `� � _ .. 1 • er L11040 . , I ,.... , ,.. __.,,,. r ‘. : I'll' . i e ...•••••• , • L., Cr .,1411. AP US ect 1:1 C 11111"Iliip •' 1 lir 6 tt '..' livp, . 0 I , • w 0 • 0 C i 10. r Icillik . > 0 11111\ i i CC • •Z < 6 r:. ter..., { 141 L % r 1 e ..1 ® W r t V � 1 • i t it Q V .� VA 1 1 1+ : r ��„, r - . . , ,,,,__ d i , ,,... . of, 2 ..." . , .‘ ....., # • -1----1- 1 - - - - . .. 1 ... " L 1 1 nil. . ip • C- t' / U .4... � f t s • it /�• a ' i • a W LLB ;i • \ ma y ' • •,• •• -•� . 41 1 LU i+. .. WI/ krzzip Sit. tf�Z \ j • 4 4 i Z Q .s 4:- - 1 i .111" As tJ J . ! l lia Photographs 6 and 7 show the connection location in Edinger Avenue. Y `. ` II' 1).6 � c"!,..'4!:-: '. - _ F I , ,�'s • AI ... .... ' ti p `� EpIN f a 2ER { , :.: •'•' fit: ,— : _, a ry i. } , ..i1 �, f 4 t , � x ` f,, � :,„, I l Y._ ' - , - ii i I Kj j - ( i� . t I � J = r^' ,, 1i I l ( _ - - ., F C am.- -•-__J 4 .—. .. - ° -71..----- i '@•1L. ��' 'u mSn ' £o- N� ,�. 3 5 ., i � �� bb. 'T i e -,G. _ I g 'ti , , t d , ~ rf - � . ti /-- r '. Y 1 � ,,. c i i? J sl s to _L. � .. t"' '� +rte,^ m � 6' -"; :i'�S� ... ,., T�.,,,.,..na�+ ,j� ,s— r.11` - _ { .' �,' -,N.- `�3 " vl =1tJ= ''R" .aa 3`_Cti ter -� nom t 1. .. ... - ."- .. . .7.. . ... . .. . ... .. . #. � - l .�° - J Photo 6. Point of Connection - City of Huntington Beach Manhole (at the intersection of Edinger Avenue and ✓ � Trinidad Lane - Looking northwest) " -r ' ,.. T t 3.1 Existing System Flows and Capacity Photo 7. Point of Connection - City of Flow monitoring of the existing 10 -inch Huntington Huntington Beach Manhole (at the intersection of Edinger Avenue Beach sewer in Edinger Avenue was conducted over a and Trinidad Street - Looking west) - 1-month period, between May 21, 2002 and June 21, 2002. The results of this study are as follows: Average Flow = 0.30 mgd (208 gpm) (0.46 cfs) • • Maximum Flow Measured = 0.71 mgd (493 gpm) (1.10 cfs) Peak Flow = 0.56 mgd (389 gpm) (0.87 cfs) Peak flows were observed to occur between the hours of 7:00 a.m. and 8:30 a.m. The existing 10 -inch sewer has a 75 percent full capacity of 0.65 mgd (450 gpm) (1.0 cfs). At the maximum flow measured during the study (0.71 mgd), the pipe is flowing 83 percent full. The downstream pump station to the 10 -inch sewer incorporates two vortex -type pumps, with a rated capacity of 300 gpm each (0.43 mgd). From the flow data, it would appear that the City's sewer collection system has adequate capacity to accept the additional 30 gpm pumping rate from the Aquatic Park Facility. The City's pump station is under capacity during the peak flow period of 7:00 a.m. to 8:30 a.m. Outside of those hours, the flow monitoring indicates influent flows less than the pump's 300 gpm rated capacity. Flow monitoring data for the 1- rhonth period is included in the Appendix of this study. The controls for the Aquatic Park Pump Station should be designed so that the facility is locked out from pumping between 7:00 a.m. to 9:00 a.m. This will require adequate on -site storage to hold the flows generated at the park during that period. A minimum on -site storage capacity of 1,200 gallons is recommended (10 gpm x 120 minutes). CITY OF SEAL BEACH 7 SUNSET AQUATIC PARK PUMP STATION CONCEPT STUDY KlSeal BeachlAquat,c ParklAquatic Park Alternatives Preliminary (3 -17 -03) SECTION 4.0 PUMPING ALTERNATIVES Two pumping alternatives have been identified for conveying flows from the Sunset Aquatic Park to the City of Huntington Beach's sewer system. Both are described in the following paragraphs. 4.1 Grinder Pump System Alternative 1 is to construct a small 30 gpm duplex submersible pump station and dual 2 -inch PVC - SCH 80 forcemains to the City of Huntington Beach Sewer System. A smaller than normal forcemain size is recommended because of the low pumping rate (minimum diameter is normally 4 inches). To be self - cleaning, a minimum velocity of 3 ft/sec is required. At 30 gpm, the velocity in a 2 -inch forcemain is 3.1 ft/sec. Because of the low flows and small diameter of the forcemain, a grinder pump is recommended. A grinder pump incorporates a serrated steel cutting ring at its inlet to shred domestic waste into fine particles, allowing them to pass through the pump, valves, and small diameter piping. A slide rail system is also recommended so that the pumps can be removed for servicing without personnel entering the wet well. A typical grinder pump and slide rail system are shown in Figure 3. The most effective cutting system for t pressure sewer pumps ti. i Opening ": � ` r Stationary t i . cutter �� f � Rotor �t r F i 0' V 4 S 4 t wit t.. j+ Y`` lam; . ' it ► r Off'^ re �r fC 4u - i v Figure 3. Grinder Pump The pump station would consist of a 6 -foot diameter T -lock lined wet well; and a 5 -foot by 6 -foot rectangular valve vault structure. The wet well would be designed with sufficient storage so that the pump station could be locked out from operation during the peak flow hours of the City of Huntington Beach's sewer system. The recommended storage volume is 1,200 gallons and is based upon a 2 -hour storage period (7:00 a.m. — 9:00 a.m.), and an influent flow of 10 gpm. For a 6 -foot diameter wet well, 6 feet of level is necessary. The bottom of the wet well should therefore be set at elevation -6.5 feet. Depth of the wet well, below the existing ground surface would be approximately 16 feet. CITY OF SEAL BEACH 8 SUNSET AQUATIC PARK PUMP STATION - CONCEPT STUDY KlSeal BeachlAquatic ParklAquatic Park Alternatives Preliminary (3 -17 -03) The valve vault would be located directly adjacent to the wet well structure. It would be approximately 5 feet deep and incorporate a full opening spring- assisted hatch. The vault will house the necessary vaiving and flow meters required for installation. A sump pump to remove drainage from the vault and a ventilation blower would also be included. All piping in the wet well and valve vault would be 316 stainless steel. PVC Schedule 80 pipe is recommended downstream of the vault as the forcemain material. Because the diameter of the discharge pipes is small (2- inch), two forcemains are recommended as a back -up system against plugging. The necessary vaiving will be provided in the valve vault to allow the City to switch between discharge pipes, as necessary. The existing Aquatic Park Pump Station No. 2 and forcemain will be filled, and abandoned in place. • The existing Aquatic Park Pump Station No. 1 will be converted to an overflow storage tank. The conversion will require all existing equipment be removed, a sloped fillet installed in the bottom, and the interior walls of the structure sandblasted and lined with 125 mils of Sancon 100, epoxy /polyurethane coating system. The existing 8 -inch influent pipe to the structure would be removed, and replaced with an 8 -inch . PVC pipe, sloping toward the new pump station. The overview structure would have a capacity of 3,200 gallons, which will provide about 6 hours of storage at average flow. Figures 4 and 5 show a concept drawing for the grinder pump station facility. 4.2 4 -Inch Pump and Forcemain Alternative 2 is to construct a 120 gpm duplex submersible pump station and 4 -inch forcemain to a large storage structure located adjacent to the proposed connection with the City of Huntington Beach's sewer system. A small pipe (1.5- inch), or pump, would, then be used to meter flow out of the structure into the City of Huntington Beach's sewer system to no more than 30 gallons per minute. The size of an equalization tank would be about 8 -foot in diameter. A high level float and telemetry would also be provided for alarming purposes. The pump station would incorporate two 120 gpm vortex -type submersible pumps in a 6 -foot diameter wet well; and an 8 -foot by 12 -foot valve vault, incorporating check and isolation vaiving, and a flow meter. The design would be similar to that of the Boeing Pump Station currently bidding. As with Alternative 1, the wet well would be 16 feet deep, incorporating sufficient storage volume so that the pump station could be locked out from operating during the peak flow hours of the City of Huntington Beach's sewer system. The alternative also includes converting the existing P ump Station No. 1 structure to an emergency overflow storage tank. Figures 6 and 7 show a concept plan for the 120 gpm pump station facility. CITY OF SEAL BEACH 9 SUNSET AQUATIC PARK PUMP STATION CONCEPT STUDY Meal BeachlAquahc ParklAquatic Park Alternatives Preliminary (3 -17 -03) T w \\ \ \ _ N s 1 \\ N S N N ti — - - ----) s s. N. N. \\\ as \ � �� �� 44. W J7 •4% N. \, N N. W \ _ IQ \ 1 \ W ___ _ ii In 0 v 1 Y 20Ct "` , \w 1rr e yeti ' I t Z 4 0.�W�3, mx • � I II �\ � W� W �( �\ w W , ¢ a_ 0 d � r J� I \ \ k �u W mow 1i 22 1,J goin 3 \•. .. 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V D yy 4 co In W . mills (1... 1 w 5� W 0. to E W S2 W 4 4 Et k it ti Z Z % Z Z Z Z Z Z Z a1 5 4 • ` 4` /�j 4 d0 i!' j P r P P P W 0 00000000 ®00000 00 0 0 eh MOM 0 J • { _= I c o Ca 1 1 01 L • . 4 - _` 4 • . i 4 • t •• :' 4 • : +7- 4 m 4 Q I a a 4; 1 1 14 III' III I di ITI A-,4 � X iii il�i' 0 111 © 1 1 I" I IL t I i Y 1.1 �a III SECTION 5.0 ALTERNATIVE COMPARISON AND COSTS The estimated cost to construct Alternatives 1 and 2 is summarized below, and presented in detail in the cost estimates included at the end of this report. Pump Station Forcemain Construction Cost Construction Bravata Drive Edinger Avenue Cost Connection Connection TOTAL 1. Grinder Pump Station $296,000 $184,000 $219,000 $480,000 - $515,000 2. Vortex Pump Station and Equalization Tank $513,000 $212,000 $255,000 $725,000 - $768,000 Note: Cost Estimates include a 10% Contingency Alternative 1: Significantly Tess expensive to construct than Alternative 2. It does incorporate small pumps and a small diameter forcemain, which may be subject to frequent plugging, and will require regular maintenance. Alternative 2: Provides a pump and forcemain design, which is consistent with the City's current design criteria and is much less likely to plug. It does, however, require an equalization structure with a small diameter outlet pipe to the City of Huntington Beach's system, which will also be subject to frequent plugging, and will require regular maintenance. The equalization tank will also be at a location which could generate odors, and will require regular cleaning by vactor truck, similar to a pump station wet well. An advantage of Alternative 2 is that if the City of Huntington Beach should improve its sewer collection system and pump station in the future. It may be possible to eliminate the equalization tank, leaving a pumping facility which is in conformance with Seal Beach's standard design. - CITY OF SEAL BEACH 14 SUNSET AQUATIC PARK PUMP STATION CONCEPT STUDY Meal BeachlAquatic ParklAquatic Park Alternatives Preliminary (3 -17 -03) 1\ • SECTION 6.0 EXISTING BRIDGE CROSSING The forcemain construction will require a crossing of an existing water channel at the Edinger Avenue Bridge. The bridge is a 280 -foot long timber structure and is shown in Photographs 6, 7, 8 and 9. As shown in the photographs, there are no existing utilities installed on the bridge, to be accommodated. The forcemain could be installed on the side of the bridge using angle -type support brackets installed at 6 -foot on- center. The forcemain should be installed within a secondary containment sleeve on the bridge to prevent leaks from directly entering the bay. An 8 -inch sleeve is required for the 4 -inch forcemain, and a 6 -inch sleeve is required for each 2 -inch forcemain. - Installation of the forcemain on the bridge will require preparation of calculations and approval by Orange County Public Facilities and Resources Department. ..I 1 M1 J y M _ 'I 1 f f M } te 5 o — oc .: --_:- _ ,— ----- _ _.; ._ _ c b r,. ` +', 's • "'$1r Its ta ._ ____ _ , . �L 4` x } tt { �h 'va ui C, s SF S - - - /• k ' ,� ,, -, , 4° , z,,�_i a 474- F 6, r �} ♦ 'r .. #. r :.. 1 t , -1. ' P F � � rizg �2'; ivf -67- , ,3. y a`„F.. ., a tt Y it ,e. i' . \. £ I , a -+4,-. �S t`/`' r- i '� _ ..- "` - "" Miff * rf, 1 E -.„ s �,, • te r w 1 it .ry - 'ice i; r Photo 6. Edinger Avenue Bridge — View looking east Photo 7. Edinger Avenue Bridge — View underneath - \ -ii .,sm n � - � �- —..'.--f:-...--,_ 3 1 w 1 Ir a T r.. e'1 - , - - ' 7 S . s; ;`: zi n 1 � - -, L 1 �1 ?,, Y` r 1 ' 6 ,-r: :.:,.� E C - ' P�� _ r+.. ' y1 -5 .� `'J .,<- 5 X1 ! ,4:' '!. -- r � 1 „1-4._.,;....-__ A4,, r - " *-...� , ,�. r0-" F,' 'r' F r i i 5 �� � ,.'T;y11 , r � •••t„, >• , 5 3 ? r Yl' , ' } r ; r t ,:.t , J ,, I ti L t " ,t F ';*- c E. - . -. "" • ry .re x .+ Photo 8. Edinger Avenue Bridge — South side of bridge - Photo 9. Edinger Avenue Bridge — North side of bridge • CITY OF SEAL BEACH 15 SUNSET AQUATIC PARK PUMP STATION - CONCEPT STUDY KlSeal BeachlAquatic ParklAquatic Park Alternatives Preliminary (3 -17 -03) SECTION 7.0 SUMMARY Two alternatives were identified for redirecting flows to the City of Huntington Beach's sewer system in Huntington Harbor. Both alternatives evaluated, limit flows discharged to no more than 30 gpm because of limited capacity available in the Huntington Beach system. Alternative 1 includes a grinder -type duplex pump station rated at 30 gpm, metering vault, and dual a 2 -inch PVC forcemains. Although the size of the forcemain is substantard, the velocity in the pipe will be at a rate which should resuspend any settled material, and the grinder pump will shred large solids to particles which should pass through the pipe easily (estimated cost: $480,000 - $515,000). Alternative 2 is to construct a standard -type duplex pump station, with a capacity of 120 gpm and a standard size forcemain (4 -inch diameter) to limit flows into the City of Huntington Beach system to a maximum of 30 gpm (estimated cost: $725,000 - $768,000). The alternative will require an equalization tank be installed at the end of the forcemain, and flow restricted into the City of Huntington Beach's system by pump or small pipe. Although Alternative 2 provides a standard -type pump station and forcemain arrangement, the flow equalization tank will be a constant location of maintenance and odors. Its remote location from the pump station may also make maintenance more difficult. The cost of Alternative 1 is significantly less than Alternative 2, and while it too will be subject to plugging because of the small pump and forcemain diameter, it would not be any more significant than the plugging which would occur in the small pipes connecting the equalization tank to the City of Huntington Beach system. Plugging may "actually be less for Alternative 1 as the solids will be macerated prior to entering the forcemain. Alternative 1 is also approximately $200,000 less expensive to implement and is therefore recommended. - There are two potential locations for connecting to the City of Huntington Beach's sewer system. The location closest to the Aquatic Park Pump Station is at Bravata Drive, in a private residential development. Connection at this location will require an easement from the Homeowners Association. The closest connection point in public right -of -way is in Edinger Avenue at the intersection of Trinidad Lane, approximately 3,800 LF from the Aquatic Park Pump Station. Both connection locations will require a channel crossing at the Edinger Avenue Bridge. The bridge is a 280 -foot long timber structure. The forcemain would be attached to the side of the bridge within a secondary containment pipe sleeve. Hanging of the pipe on the bridge will require approval from Orange County Public Facilities and Resources Department. Permits required for the work will include: . • Coastal Commission . • RWQCD Dewatering Permit • City of Huntington Beach Encroachment Permit • County of Orange Encroachment Permit • City of Huntington Beach Sewer Connection Permit CITY OF SEAL BEACH 16 SUNSET AQUATIC PARK PUMP STATION CONCEPT STUDY K1Sea1 BeachlAquatic ParklAquatic Park Alternatives Preliminary (3 -17 -03)