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HomeMy WebLinkAbout04/03/1991, 2 - BRIDGE REPLACEMENT PROJECT - ELKS LANE AT SAN LUIS OBISPO CREEK, CITY PLAN NO. L-10H. p� MEETING DATE CTLy Of San lids OBISPO April 3, 1991 COUNCIL AGENDA REPORT INUMBER: FROM: David F. Romero, Public Works Director j• Wayne A. Peterson, City Engineer,, -; John W. Hawley, Supervising Civil Engineer SUBJECT: Bridge Replacement Project - Elks Lane at San Luis Obispo Creek, City Plan No. L-10H. RECOMMENDATION: By motion direct staff to complete plans to replace the existing Elks Lane Bridge at San Luis Obispo Creek. BACKGROUND: Elks Lane Bridge was constructed .in 1939. The existing structure is 24-feet in width and spans 92 feet across San Luis Obispo Creek. The concrete slab and timber roadway deck is. supported on two abutments and four timber-pile bents located within the creek channel: The structure has no pedestrian walkways. Based on the level of deterioration, non- standard features which affect safety, load capacity, and'the obstruction to stream flow caused by the timber pile bents and cross- bracing, the bridge is considered by the Caltrans Office of Structures Maintenance and Investigations to be in a deficient condition. As a result of this deficiency rating, the City is eligible to receive Federal Bridge Replacement and Rehabilitation Funds (HBRR) towards replacing the bridge (85% maximum--the remaining costs are a City responsibility) . In addition, Priority No. 21 of "Points of Restricted Capacity--Four Major Creeks" of the Flood Management Policy adopted by the City Council in June 1983, also recommended removal .or replacement of the bridge because of its restricted hydraulic capacity. Most recently, the Community Development Department completed the "Initial Study of Environmental Impact" to remove or replace the bridge (Exhibit A) . Their action was to file a mitigated negative declaration and the overall conclusion stated that "either replacing or eliminating the Elks Lane Bridge, under existing or future conditions, would result in some beneficial and some adverse impacts. No adverse impacts are significant to the point that an environmental impact report (EIR) must be prepared. " DISCUSSION: Recent development of the Circulation Element and the environmental study prepared for this project has led staff to question the need for the Elks Lane Bridge in terms of traffic circulation, and whether the high cost of replacement is economically beneficial to the City. There is no indication that Elks Lane will ever be an important link in the City's circulation. Currently the street's main purpose is to provide Z �� '"111111111lllpW11 city of San L,-.S OBISPO COUNCIL AGENDA REPORT City Plan No. L-10H - Elks Lane Bridge Meeting of April 3, 1991 Page 2. access to adjacent properties and a by-pass to Higuera Street and Highway 101. If the bridge were removed, the Elks Club and the Cemetery would have to enter and exit only from Higuera Street and the drive-in theater and mobile home park only from Prado Road. This may cause some inconvenience to residents, and police and fire response times would be increased (see attached reports by Police and Fire Departments) , but the total impact per the initial study is not considered to be significant. It is possible that the area south of the creek will be developed with commercial uses. Future traffic levels on Elks Lane are projected to increase from 500 ADT (existing) to 6200 ADT (year 2020) , associated mostly with redevelopment of the drive-in theater and the vacant land south of the creek. The Draft Circulation Element proposes that Prado Road be widened to six lanes between Higuera Street and Highway 101, South Higuera be widened to four lanes, and that a full interchange be constructed at Prado Road and Highway 101. Per the environmental study, eliminating the Elks Lane bridge would not adversely affect access to these commercial areas so long as the above changes to the road system are carried out. Eliminating the bridge would also cause traffic to use South Higuera via Prado which is currently signalized, in lieu of the Elks-Higuera intersection. If the bridge were replaced, it is likely that this intersection would also require signalization under built-out conditions. i Considering the hydraulic capacity, the existing bridge (92 feet long) can convey an 8-year storm with two-feet of freeboard including an allowance for debris trapped at the structure's timber-pile supports. Either replacing or complete removal of bridge, and no change to the channel cross-section, will allow an 18-year storm to pass with two- feet of freeboard. In order to convey a 50-year storm, the channel would require widening to twice its current width, construction of a vertical wall along the southerly bank, and extending the bridge 90 feet to the north. ALTERNATIVES: 1. Remove and Replace the Elks Lane Bridge (Staff Recommendation) Staff will proceed with plans and specifications to replace the existing bridge structure. To date, the foundation investigation, survey work, and environmental study have been completed. Advantaces: I The new bridge would be built to current Federal and State Standards, widened to 40-feet to provide for two travel and bike lanes and a six- foot sidewalk on the east side. Because of its deficient condition the City is eligible to receive Federal HBRR funding (85%) . However, per a z —Z 1111!�JJWJJ city of san t s owpo COUNCIL AGENDA REPORT .M ;f City Plan No. L-10H - Elks Lane' Bridge Meeting of April 3, 1991 Page 3 . recent State policy, federal funding for local agency bridge projects will not be available until after the State's Seismic Safety Retrofit Program is fully funded (September 30, 1992) . Hence, construction-, is estimated to occur at its earliest in 1993 . , The traffic circulation patterns and fire response times in the area would not change from the existing situation. The replacement bridge will accommodate 18-year storm flows with two-feet of freeboard as compared to 8-year flows conveyed by the existing structure. Disadvantaces: If, in the future, land area south of the creek is allowed to deve-lop, a significant increase in traffic would result on both Elks Lane }md Prado Road. The Higuera-Elks intersection could be impacted sufficiently to warrant signalization, thereby impedingtraffic flow along South Higuera. Elks Lane would also be used as a pass-by to= Highway 101, causing additional traffic impacts at the Prado/Elks intersection and the Corporation Yard area. The increase�k-traffiq may be found to be unacceptable to the residents in the mobile-home park. Should San Luis Obispo Creek be widened to accommodate a 50-year storm flow, the bridge structure would have to be extended an additional 90 feet in length, and vertical walls would be required on the south bank upstream and downstream of the bridge. The City would not be eligible for Federal Funding for the extension or creek widening projects. ; Construction of a new bridge and abutments will have an impact on.-the creek channel environment, possibly resulting in some daigage to the large eucalyptus trees along the banks. 2. Remove the Elks Lane Bridge and Do Not Replace. The City will be required to set a public hearing and follow all - recommended legal requirements for street closure prior to removal of the bridge. Bridge removal will include construction: of turn-aroVnd areas on Elks Lane North and South of the creek as requested by the Fire Department. Advantages: The balance of City funds allocated for replacement and otherwise not utilized on the replacement project can be utilized for other capital projects with high priority. The restricted hydraulic. capacity of the creek would be improved to convey an 18-year storm with a;• two-foot freeboard in lieu of the current 8-year storm capacity. _ Removal operations will not significantly impact the creek envirgnmgnt, given the relative simplicity of the existing bridge structure. , Assuming future development and build-out of the area south of the -creek, _ Z '3 cityo f San WIS OBISpo COUNCIL AGENDA REPORT City Plan No. L-10H - Elks Lane Bridge Meeting of April 3, 1991 Page 4. removal Vill benefit the Higuera-Elks intersection. Additional traffic will be routed to the Prado-Higuera intersection which is currently signalized. City maintenance costs will be minimized. Traffic volumes in the dead-end street should be limited. This may be beneficial for residents. Disadvantages.- . Under current land-use and fire response conditions, removal of the bridge would incrementally reduce the level of police and fire protection for the mobile home park, and drive-in theater. The initial j study-Andicated the impact would not be significant. (For additional information, see the attached memos from Police and Fire Departments. ) Traffic circulation would be affected , particularly for the drive-in theater and the mobile park, causing some inconvenience, but would not restrict access. Should the City decide to construct a bridge in the future, Federal HBRR funds could not be utilized. 3. No Project (Bsisting Bridge to Remain) The existing bridge will remain and be maintained by the City. Biennial safety inspections by Caltrans will continue. Should the j bridge continue to deteriorate to a level which affects its structural ' integrity, it will be posted for a safe load capacity or closed. Eventually the bridge must be removed and either replaced or the road permanently closed. Advantages: i City funds allocated for replacement can be utilized on other capital projects with high priority. Local residents will continue to have j flexibility in route selection provided by the bridge. Disadvantages: Existing restricted hydraulic capacity will continue, with possible damage or destruction of the bridge should debris from storm water build-up at the structure. The restricted capacity increases the frequency of flooding and possibility of damage to adjacent properties. The deteriorated condition of the bridge will continue to a stage in which the structure is unsafe and will have to be removed. I Future bridge replacement might be City's total responsibility. There will be continued city expense in maintaining the bridge. 7_ ,111011111 FIJJ city of san tuis oBispo COUNCIL AGENDA REPORT City Plan No. L-10H - Elks Lane Bridge Meeting of April 3, 1991 Page 5. FISCAL IMPACT: The fiscal years 1989-91 Capital Improvement Plan, page D-39, includes $479, 000 for design and construction to remove and replace the Elks Lane Bridge (85% of this money to come from the State) . Estimated costs for the various project alternatives are as follows: Alternative 1. Remove and Replace the Elks Lane Bridge (Staff Recommendation) . To remove the existing bridge, and construct a new bridge to current Federal and State Standards is estimated to cost $600,000. Fund sources include: Federal HBRR Funds (85%) : $510,000 City Funds (15$) : $ 901000 If in the future the creek is widened to accommodate a 50-year storm flow, the estimated cost to extend the bridge 90 feet is another $600, 000* with no federal participation, and the possible installation of traffic signals at both intersections (Prado and Higuera) $200,000. *Today's figure. i Alternative 2. No proiect (existing bridge to remain) Minimal costs associated with yearly maintenance and repairs. Eventually major expenses to replace bridge with no assured assistance from the State or Federal Government. (Estimated cost of $1,200,000* if creek is widened to convey a 50-year storm. ) Alternative 3. Remove Elks Lane Bridge and Do Not Replace. To remove the existing bridge structure and abutments and construct Fire Department turn-around areas (a mitigation required by Environmental Study) is estimated to cost $30,000. RECOMMENDATION: By motion direct staff to continue preparing plans for the replacement of the Elks Lane Bridge. h1/L01H-sr bv 7-S i CAL POLY HIGHLAND v \0� a R RAMONA � � 0 Q 0 LAGUNA � LAKE SOUTH �, z a \ v OOTHW000 J�13 ORCUTT iV m n o, Jy PROJECT LOCATION TANK FARM cIty of VICINITY MAP "A san Luis OBISPO p ELKS LANE BRIDGE OVER SAN LUIS CREEK ���I►i►lilllllllllllllllll III I� CityO SMvu�s OBISPO 990 Palm Street/Post Office Box 8100 • San Luis Obispo, CA 93403.8100 September 18, 1990 Mr. John Hawley Engineering Dept. City of San Luis Obispo PO Box 8100 San Luis Obispo, CA 93403-8100 SUBJECT: ER 29-90 Elks Lane at San Luis Obispo Creek Dear John: On September 12, 1990, I reviewed your project's potential effect on the environment. My action was to file a mitigated negative declaration. That means that I determined the project will cause no significant harm to the environment, and no further environmental study will be required because of the changes you have agreed to make in your original proposal. The declaration is issued for the amended project. The changes are listed on the attached sheet. Please sign the original and return to my office as soon as possible. Please contact me immediately if this doesn't coincide with your understanding of the changes. A negative declaration could be reversed later, either on appeal or by automatic review by a decision-making body. Appeals may be filed by anyone, either now or shortly before your project is reviewed by the Architectural Review Commission, Planning Commission, or City Council. With or without an appeal, a negative declaration is automatically reviewed by the Planning Commission and council -- and sometimes the ARC -- when they review the project itself. If you have any. questions, please contact Glen Matteson at 549-7165 as soon as possible. Stere y, RR Arnold B. Jonas, D rector Community Develop nt ATTACHMENT: Initial Study ER 29-90 Remove or replace the Elks Lane Bridge Elks Lane at San Luis Obispo creek The following measures are included in the project to mitigate potential adverse environmental impacts. Please sign the original and return to my office as soon as possible. 1. If the bridge is removed, the city will provide adequate space for turning fire trucks, to the approval of the Fire Marshal. Monitoring: Fire Department review of final bridge demolition proposal. 2. Any eucalyptus tree affected by root cutting during construction will be pruned for structural safety and to balance foliage with root network, under the supervision of a qualified arborist. Monitoring: Community Development staff review of construction plans and specifications; Public Works staff inspection during construction. 3. A qualified archaeologist will train the project's construction contractors in how to recognize resources that may be encountered. If excavations encounter archaeological resources, construction activities which may affect them shall cease. The Community Development Director shall be notified of the extent and location of discovered materials so that they may be recorded by a qualified archaeologist. Disposition of artifacts shall comply with state and federal laws. A note concerning this requirement shall be included on the grading and construction plans for the project. Monitoring: Community Development staff will check construction plans, review the archaeological-services contract, and visit the site during construction. APPROVED BY: QZt,) Arnold B. Jonas, D ctor Community Developmeenn City of San Luis Obispo Applicant -2, CItY of San WIS OBISpo t INITIAL STUDY OF ENVIRONMENTAL IMPACT SITE LOCATION Elks Lane at San Luis Obispo Creek APPLICATION NO. 29-90 PROJECT DESCRIPTION Remove or replace the Elks Lane bridce APPLICANT_ City Of San Luis Obispo (John Hawley) STAFF RECOMMENDATION: X NEGATIVE DECLARATION X MITIGATION INCLUDED EXPANDED INITIAL STUDY REOUIZFg_ ENVIRONMENTAL IMPACT REPORT REQUIRED PREPARED BY Glen Mattes (��IJ DATE 9-7-90 COMMUNITY DEVELOPMENT DIRECTOR'S ACTI n DATE 'S/17-/SO Ml &PED 1�E( }Z1U��ECLRRAII ►1`� SUMMARY OF INITIAL STUDY FINDINGS 1.DESCRIPTION OF PROJECT AND ENVIRONMENTAL SETTING 11.POTENTIAL IMPACT REVIEW POSSIBLE ADVERSE EFFECTS A. COMMUNITY PLANS AND GOALS ................................................... NO* S. POPULATION DISTRIBUTION AND GROWTH.......................................... NO C. LAND USE ................................................... .................... NO D. TRANSPORTATION AND CIRCULATION .............................................. YES* E. PUBLICSERVICES ................... 'Y.ES* ................... F. UTILITIES........................................................................ NO G. NOISE LEVELS ................................................................... NO* H. GEOLOGIC B SEISMIC HAZARDS&TOPOGRAPHIC MODIFICATIONS .................... NO I. AIR QUALITY AND WIND CONDITIONS............................................... NO J. SURFACE WATER FLOW AND QUALITY .............................................. NO* KPLANT LIFE...................................................................... YFS* LANIMAL LIFE..................................................................... Nn M. ARCHAEOLOGICALIHISTORICAL ................................................... YES* N. AESTHETIC ...................................................................... NO O. ENERGY/RESOURCE USE .......................................................... NO P. OTHER ....?ubi.i.C.Safety..-..toxlCS........................................ NO* Ili.STAFF RECOMMENDATION 'SEE ATTACHED REPORT 1 sees INITIAL ENVIRONMENTAL STUDY 29-90 Elks Lane Bridge Removal or Replacement DESCRIPTION OF PROJECT & SETTING The City of San Luis Obispo in considering the removal or replacement of the Elks Lane bridge over San Luis Obispo Creek The existing structure has four timber-pile supporting sections and a paved timber deck carrying a two-lane road. The bridge is 24 feet wide and about 92 feet long, from abutment to abutment. It crosses the creek at a point where flow is seasonal. If the bridge is replaced, the new bridge would have a clear span between abutments of 70 feet. It would be 40 feet wide, providing a five-foot walkway on one side, two twelve-foot travel lanes, and two four-foot bicycle lanes. The replacement bridge would be in the location of the existing bridge, with centerlines nearly coincident, and located in the western part of the existing 65-foot-wide right-of-way. New abutments, wing walls, and approaches would be constructed POTENTIAL; EMPACT REVIEW A. Community plans and goals No policies of the general plan directly address the issue of removing or replacing this bridge. Specific traffic circulation and emergency access issues are addressed under item D below. Removing the pilings, which obstruct flood flows, would be consistent with the city's Flood Management Polio. D Transportation and circulation Setting Elks Lane is a local commercial street. It provides access to adjoining properties, an alternate route to properties on Prado Road, and access to the Highway 101 ramps at Prado Road. Existing land uses directly served by Elks Lane include the Elks Club and the cemetery north of the creek, the 24-unit Valley Vista mobile home park adjacent to and south of the creek, and a drive-in theater and a gas station near the corner of Prado Road and Elks Lane. The mobile home park is a non-conforming residential use in a conservation/open space zone, and is subject to flooding. The area south of the creek is zoned conservation/open space, with minimum parcel sizes of five or 10 acres. The general plan designates the area south of the creek as "interim 2 '/� ER 29-90: Elks Lane Bridge 2 conservation/open space," which means that the area should remain open until the area's flood problems are eliminated. Assumptions About the Future For purposes of traffic modeling, the city's circulation studies assumed that the area south of the creek would eventually be developed with commercial uses having a total of about 500,000 square feet gross floor area. Future traffic levels on surrounding streets and anticipated changes would be as shown in the following table. Existing Future (2020) Change South Higuera Street 159000 ADT 21,000 to + 6,000 to 31,000 ADT + 169000 ADT Prado Road 4,000 ADT 20,000 to + 16,000 to 312000 ADT + 279000 ADT Elks Lane 300 to 500 ADT 69200 ADT + 5,700 to + 50900 ADT Traffic increases on Higuera and Prado would be caused by development throughout the city, but particularly in the airport area. Traffic increases along Elks Lane would be associated mostly with redevelopment of the drive-in theater and vacant land south of the creek. Consistent with the draft Circulation Element, the following changes would be made: - Widen Prado Road to six lanes between Highway 101 and Higuera; - Construct a full interchange at Prado and Highway 101; - Widen South Higuera Street uniformly to four lanes; - Widen Highway 101 to six lanes; Impacts Removing the Elks Lane Bridge (no replacement) Impacts Under Current Land Use, Circulation, and Emergency Response Conditions Removing the bridge would limit access to land uses adjoining Elks Lane. Assuming most traffic to and from the Elks Club is from the north, removing the bridge would have little impact. Z - /l ER 29-90: Elks Lane Bridge 3 The cemetery is a low traffic-generating use and elimination of the bridge would have little effect. Traffic associated with the drive-in theater would be limited to the use of Prado road and Elks Lane south of the creek. Peak traffic periods for the drive-in theater are during evening hours and on Sunday for the swap meet, so traffic diversion to Prado, Highway 101 and Higuera Street caused by removal of the bridge should not add significantly to peak travel on those roads, which occurs on weekday mornings and afternoons. Access to the mobile home park from the north would have to use Prado Road, which would be less convenient. Also, access to the drive-in would be less convenient for people approaching from the north. Traffic volume on Elks Lane at both ends would be reduced, to the extent that the limited amount of through traffic would use Prado and Higuera. A portion of the traffic now accessing South Higuera Street at Elks Lane would use the Prado Road route, further loading Prado Road, the Prado-South Higuera signalized intersection, and South Mguera between Elks Lane and Prado Road. Conclusion: Under current land use conditions, removing the bridge would not significantly impact general vehicle access or traffic levels on alternate routes. The Elks Lane area is within the outer service limits of Fire Station #1 at Garden and Pismo streets and Fire Station #4 at Madonna Road and Los Osos Valley Road. The city's standard for adequate fire-fighting response is for equipment to reach the site within four minutes of receiving a call. According to 1988 response-time estimates for the airport area by the city Fire Department: Uses along Elks Lane are at the edge of, or slightly beyond, four-minute response from Fire Station #1 and beyond four-minute response from Station #4. Elimination of the Elks Lane Bridge would increase the response time to areas south of the creek from Station #1, to exceed the four-minute standard; response times from Station #4 would be unchanged. Land uses which would have a longer response time from ER 29-90: Elks Lane Bridge 4 Station #1 include the mobile home park, the drive-in theater, and the gas station. Conclusion: Under current land-use and fire-response conditions, removal of the bridge would reduce the level of fire protection for the mobile home park, the drive-in theater, and the gas station, but the impact would not be significant. Potential mitigation: Build a new Station #1 at the comer of Nipomo and Pismo streets (the recommended new site for a headquarters station). The new station would be closer to Elks Lane and would improve response time slightly. (However, areas south of the creek would continue to be beyond four-minute response time). Build an overpass and extend Prado Road westward to Madonna. This would improve access to the area from Fire Station #4 at Madonna and Los Osos Valley roads. The area south of the creek would probably be within four minutes response. Relocate the mobile home park within an adequate response area. Impacts Under Future Land Use, Circulation, and Emergency Response Conditions Assuming that the area south of the creek develops with commercial uses, eliminating the Elks Lane bridge would not adversely effect access so long as that the changes to the road system listed above are carried out. The concern that the changes may not be carried out for many years can be addressed by conditioning any future development in the vicinity on completion of the road changes. With the substantial increase in traffic caused by new development, the city would logically emphasize the use of a new, full interchange at Prado Road. Eliminating the Elks Lane bridge and requiring traffic to use either Highway 101 or South Higuera via Prado Road would eliminate traffic loading of the Elks Lane leg of the Elks-Higuera intersection. (This intersection would have to be signalized under build-out conditions, if the bridge is replaced.) In addition, the segment of Higuera Street north of Madonna Road could become overloaded under future traffic conditions. Emphasizing the use of Highway 101 (by removal of 2' . 13 ER 29-90: Elks Lane Bridge 5 the Elks Lane bridge) could have a beneficial effect on the level of service on Higuera Street between Madonna Road and Marsh Street, while having a negative impact on Highway 101, which will be heavily used. On the other hand, emphasizing Highway 101 by removing the bridge could have a negative impact on traffic flow on Prado Road and at the Prado-Higuera intersection; the severity of the impact would depend on the extent of improvements to Prado Road. (North-bound traffic from areas south of the creek, having destinations over about one mile away, would probably use the freeway, while traffic with closer origins/destinations would probably use South Higuera Street.) Conclusion: Under future land use conditions, removal of the Elks Lane bridge would not adversely impact general access to the Elks Lane area; it may benefit Higuera Street by diverting traffic to Highway 101. If flooding in the area is not alleviated and the current low-intensity uses are retained, traffic impacts of removing the bridge would be insignificant. Under future traffic conditions, emergency response to the area from either Station #1 or Station #4 would be greater than four minutes. Relocating Station #1 to the comer of Nipomo and Pismo streets would improve response time to uses north of the creek. However, given the projected level of downtown traffic congestion, response times from the new station location probably would be greater than four minutes. The response time from Station #1 to uses South of the creek would certainly be greater than four minutes, since the route would be about one mile longer than with the bridge. If Prado Road is extended over Highway 101 to connect with Madonna Road, response times from Fire Station #4 would be improved; they would probably be within four minutes. However, actual response time tests will be needed under future conditions to determine actual times. Conclusion: Given future circulation improvements, such as the connection of Prado Road to Madonna Road, city response time standards could be met. However, actual field testing under future conditions should be done at the time that any future development within the area south of the creek is proposed. If response times are judged to be substandard, other mitigation measures may be available. Such mitigation would affect new development, probably not existing uses. It could include alarm and automatic fire-suppression systems that are not normally required. Such mitigation would not eliminate all concerns for medical or law-enforcement emergency response. (Until the city adopted a requirement for automatic fire sprinklers in nearly all z -/� ER 29-90: Elks Lane Bridge 6 adopted a requirement for automatic fire sprinklers in nearly all new buildings, sprinklers were often cited as mitigation for fire- service impacts for projects beyond four-minute response time. Now that sprinklers are required, the four-minute response standard may be a less useful criterion.) Replacing the Elks Lane Bridge and maintaining the Elks Lane connection between South Higuera Street and Prado Road Impacts Under Current Land Use, Circulation, and Emergency Response Conditions Circulation patterns in the area would not change. With current traffic levels, intersection and road capacities would not be exceeded. Although the Elks Lane-South Higuera Street intersection would continue to be awkward, under current levels of usage no substandard conditions would be created by replacing the bridge. Conclusion: Replacing the Elks Lane Bridge will not adversely affect traffic under current land use and circulation conditions. Response times from fire stations #1 and #4 would not be affected. Uses along Elks Lane are at the edge of, or are slightly beyond, four minutes response from Fire Station #1, and are clearly beyond four minutes response from Station #4. . Conclusion: Replacing the Elks Lane Bridge will not adversely affect response times to the Elks Lane area. Impacts Under Future Land Use, Circulation, and Emergency Response Conditions If the area south of the creek is allowed to develop with commercial uses, then a significant increase in traffic on Prado Road would result. By replacing the Elks Lane bridge, part of that traffic would be encouraged to use Elks Lane to access South Higuera Street and part of the traffic would use Prado Road and Highway 101 (assuming a full freeway interchange has been developed). Increased use of the Elks Lane-South Higuera intersection (which is now controlled with a stop sign) could warrant signalization. If signalized, through traffic flow on South Higuera would be impeded. In addition, the segment of South Higuera Street north ER 29-90: Elks Lane Bridge 7 of Madonna Road could become overloaded under future traffic conditions. The level of service on Higuera Street between Madonna Road and Marsh Street would approach "F' during peak traffic periods, meaning unacceptable delays with some vehicles waiting through more than one signal cycle. This loading might be reduced if traffic from the Elks Lane area was diverted to Highway 101. Conclusion: If the area south of the creek develops with commercial uses, replacing the Elks Lane bridge could reduce the level of service on South Higuera Street north of Elks Lane and on the Elks Lane-South Higuera Street intersection. However, these. impacts would be reduced if a full interchange was constructed at Prado Road and Highway 101. Under future traffic conditions, emergency response to the area from either Station #1 or Station #4 would be greater than four minutes. Relocating Station #1 to the comer of Nipomo and Pismo streets would improve response time to uses north of the creek. However, given the projected level of downtown traffic congestion, response times from the new station location probably would be greater than four minutes. If Prado Road is extended over Highway 101 to connect with Madonna Road, response time from Fire Station #4 would be improved, and probably would be within four minutes. However, actual response time tests will be needed under future conditions to determine actual times. Conclusion: Fire response times under future land use and circulation conditions probably would be substantially the same with or without the Elks Lane bridge. Alternate routes to the scene of a crime or an emergency do help assure timely response by police, fire, medical, and utility services. Therefore, removing the bridge and not replacing it would reduce the options for emergency access to properties along Elks Lane. The impacts would not be significant. If the bridge is removed, each end of Elks Lane would require some provision for turning vehicles, including fire trucks. A tum-around of about 60 feet diameter could be provided to the north in the existing right-of-way, with some filling of a low area. A tum-around wider than 40 feet at the south end would require additional right-of- way and, depending on location, removal of dwellings from the mobile home park. Fire Department standards call for dead-end roads serving potential fire locations to have, within 150 feet of the end, a turning circle with an outside diameter of 90 feet, or a roadway "T' with 58-foot-long legs. Tum-arounds have not been designed. "I" Z -� Co ER 29-90: Elks Lane Bridge 8 arrangements may be accommodated on developed sites, such as the Elks Club, and can be required of future development in the area. The following mitigation is recommended. Mitigation: If the bridge is removed, the city will provide adequate space for turning fire trucks, to the approval of the Fire Marshal. Monitoring. Fire Department review of final bridge demolition proposal. Removing the bridge would make travel to and from the mobile home park particularly inconvenient for those walling, riding bicycles, or riding the city bus system- The city has begun to identify and obtain right-of-way for a bicycle/pedestrian.trail along San Luis Obispo Creek, but a bicycle/pedestrian bridge at this location has not been identified. Overall conclusion: Either replacing or eliminating the Elks Lane bridge, under existing or future conditions, would result in some beneficial and some adverse impacts. No adverse impacts are significant to the point that an environmental impact rdport (EIR) must be prepared. E. Public services Impacts on emergency service access are discussed under the preceding "Transportation and circulation" section. G. Noise levels If the mobile home park remains, replacing the bridge and allowing commercial development of the drive-in site would result in additional traffic noise exposure to residents. Noise levels could exceed city standards. Replacing the bridge would not cause this impact, but would enable it. This exposure would be avoided by any one of the following: removal of the mobile home park; removal of the bridge; continuation of the drive-in area as open land or low-intensity recreational use. J. Drainage. flooding_ and water qualily The vicinity is subject to flooding to a depth of about two feet during the intensity of storm that is expected to occur about once in 100 years (a "100-year storm"). The channel from just downstream of the Prado Road bridge; extending upstream past this location and through most of the city, is not adequate to convey runoff from storms more intense than a 30-year frequency. The Elks Lane Bridge itself can accommodate an eight-year storm (about 3,000 cubic feet per second), with an Z -� ' ER 29-90: Elks Lane Bridge 9 allowance for debris trapped against the bridge structure. The conceptually designed replacement bridge, without substantial channel modifications, would allow 18-year storm flows to pass (about 5,000 cubic feet per second). To accommodate a 50-year storm (9,500 cfs), the channel width would have to be approximately doubled, to 160 to 180 feet, vertical walls would be required on the west bank upstream and downstream from the bridge, and the replacement bridge would have to be about twice as long as the conceptual design evaluated in this report. Removing or .replacing the existing.bridge would help avoid flooding from storms in the 10- to 20-year range, but by itself would not reduce the depth or extent of flooding from storms more intense than about 30-years frequency. In a listing of nine projects to reduce flooding along major waterways in the city, removing the Elks Lane bridge was ranked number 2 (City of San Luis Obispo Flood Management Policy June 1983). Scheduling demolition and construction during the dry season of a year with average or less rainfall would avoid impacts to water quality, since there would be no surface flow at the location. L Plant life Castor bean, anis, grasses, and blackberries grow along the channel in the vicinity. Significant trees close to the bridge are: At 15 to 35 feet from the southwest comer, three eucalyptus, 80 to 100 feet tall and with trunks of two to five feet in diameter; At 30 to 65 feet from the southwest comer, five cypress, 30 to 60 feet tall, with one- to three-foot trunks; At 40 to 60 feet from the southeast comer, eucalyptus with three- and five- foot trunks, and a black walnut; At 35 and 60 feet from the northeast comer, a eucalyptus with a five-foot trunk, a cypress with a three-foot trunk, and a multi-trunk eucalyptus resprouted from a five-foot trunk; At 50 to 80 feet from the northwest comer, a large group of willows. The conceptual design would not require any of these trees to be removed. However, excavations for abutments and wing-wall footings would probably sever major roots for the two large eucalyptus trees, one on each side of the bridge on the south bank, since the walls would be within four to eight feet of the trunks. Such root cutting Z-160 ER 29-90: Elks Lane Bridge 10 would stress the trees and make them less stable. Therefore, the following mitigation should be incorporated. — Mitigation: Any eucalyptus tree affected by root cutting during construction will be pruned for structural safety and to balance foliage with root network, under the supervision of a qualified arborist. Monitoring: Community Development staff review of construction plans and specifications; Public Works staff inspection during construction. M. Archaeological and historical resource The site probably hosted Chumash use before European settlement. However, natural changes within the flood plain and soil disturbance from construction after European settlement have probably removed or damaged prehistoric cultural materials. In conjunction with the wastewater treatment plant upgrade and sewer main replacement (ER 46-89), this vicinity was surveyed by an archaeologist and a records search was performed (Clay Singer, December 12, 1989). No cultural resources or sites were identified which would be affected by this project A previous reconnaissance at this site found no resources (Archaeological Potential at Elks Lane Bridge Project, Charles Dills, February 26, 1978). However, excavation in conjunction with footings or abutments for a replacement bridge could encounter archaeological resources. To ensure that any materials will be properly dealt with, the following standard mitigation is recommended. Mitigation: A qualified archaeologist will train the project's construction contractors in how to recognize resources that may be encountered. If excavations encounter archaeological resources, construction activities which may affect them shall cease. The Community Development Director shall be notified of the extent and location of discovered materials so that they may be recorded by a qualified archaeologist. Disposition of artifacts shall comply with state and federal laws. A note concerning this requirement shall be included on the grading and construction plans for the project. Monitoring: Community Development staff will check construction plans, review the archaeological-services contract, and visit the site during construction. The bridge, built in 1939, does not have any unique features or known association with events that would make it historically significant. No other structures would be affected by the project. ER 29-90: Elks Lane Bridge 11 P. Public safetx While the bridge is not in imminent danger of collapse, it has been qualified for 86 ' percent federal funding for replacement of substandard bridges. An extreme flood which undermined the pilings or caused lateral stress from pressure on trapped debris, combined with crossing by a heavy vehicle, could be hazardous. Removing or replacing the bridge would avoid this hazard. Section D above discusses the emergency access impacts of removing and not replacing the bridge. A soils investigation found hydrocarbon contamination on the southwest side of the creek, at a depth of about 18 feet (petroleum odor in soil), 21 feet (trace of free product), and 25 feet (oily sheen on ground water) [Soils Engineering Report for the P=osed Elks Lane Bridge Replacement Pacific Geoscience, August 1989]. Additional investigation has been performed (Initial Site Characterization, Elks Lane Bride Projem Earth Systems Environmental, Inc., August 1989, and Site Investigation Report for Unocal Pipeline, GeoResearch, March 10, 1990). The full extent of the contamination has not been determined, though it appears to be limited to the southwestern side of the creek. The material appears to be crude oil. Detectable amounts of acetone, phenanthrene, and 1,1,1-trichloroethane have been found. While two petroleum pipelines running along the east side of Elks Lane are probably the source, a specific source has not been identified. These findings have been referred to the city Fire Department and the California Regional Water Quality Control Board for review and recommendation. Additional monitoring will be performed, but the bridge project is not expected to affect or be affected by the contamination. Bridge removal or replacement will be coordinated with any soil and water decontamination that is planned for the area gmD: er29-90.wp MEMORANDUM TO: Wayne Peterson, City Engineer FROM: Bob Neumann, Interim Fire Chief DATE: March 8, 1991 SUBJECT: Elks Lane Bridge The Elks Lane Bridge is of vital importance to the City Fire Department and we are strongly opposed to its removal. The removal of the bridge would reduce the levels of fire protection, life safety and medical response for parcels south of the bridge. For example, the existing substandard mobile home park consists of a number of older, pre-1972, mobile homes which have a particularly bad history of rapidly burning and posing a significant life hazard. Additionally, tenants in mobile home parks tend to be older and utilize the Fire Department medical services more frequently. The significant open space remaining in this area will undoubtedly, in build out, be provided with fire protection and early warning devices. However, approximately 75% of the emergency response activity provided by the Fire Department involves medical response for which no built-in prevention may be provided. No mitigation is available for the public safety impacts of removing the bridge. Response times are vital to the very basis of Fire Department operations. Any disruption of existing response routes is always viewed with concern by Fire Department personnel as Fire Station locations are set by travel distances. This particular disruption is compounded by the potential loss of a creek crossing which in time of flooding could even further isolate an area of the City. Please note attached response time test performed by Fire Department. Please note that all stations are not equipped with similar equipment which increases the importance of the bridge for the immediate availability of the ladder truck and Advanced Life Support units coming from Fire Station #1. M E M O R A N D U M TO: Wayne Peterson, City Engineer FROM: Robert F. Neumann, Interim Fire Chief DATE: March 8, 1991 SUBJECT: Response Times - Elks Lane Below are the response times that you requested. January 30, 1991 Code 3 Simulation Responses 1. Sta. 1 to N. Elks Bridge: 2:36 2. Sta. 1 to S. Elks Bridge: 4:13 Via Higuera & Prado 3. Sta. 4 to S. Elks Bridge: 3:53 Via Freeway & Prado Offramp 4. Sta. 4 to N. Elks Bridge: 5:21 Via Freeway & Madonna Offramp 5. Sta. 4 to N. Elks Bridge: 3:00 Via Madonna Road 6. Sta. 1 to S. Elks Bridge Via Prado Overpass Overpass Estimate: 3:45 * Sta. 1 to Elks & Higuera: 2:11 * Sta. 4 to Prado Offramp: 3:20 RFN:pjs Z'2Z i���llllll I I II I II uglil!I��!jl�!�I{ iii ,�I�i i�� ' I�il�I� city of san lues oaspo POLICE DEPARTMENT Post Office Box 1328 — San Luis Obispo, CA 93406.1328— 8051549.7310 TO: Chief Gardiner R E C El V E FROM: Sergeant La Hargoue MAR 6 1991 ON DATE: Janus 31 1991 CITY OF SAN L IS OBISP January � CITY OF SAN LUIS OBISPO SUBJECT: Elks Lane Bridge Comments I have reviewed the attached documentation submitted by Chief Dolder regarding the proposals for the replacement/removal of the Elks Lane Bridge. I hope that you will find the following comments helpful. Police Response Impact: Response times to calls could be effected if the bridge was removed and not replaced. It, however, is difficult to predict just how often that time would be effected during a police response. Unlike the Fire Department, the Police Department does not respond from fixed locations within the city. If an incident occurs requiring an emergency police response, officers may be just as likely to respond from either the north or the south. It all just depends where the officer is patrolling at the time of the call. The Fire Department has preset routes of response from fire stations and the removal of the bridge will probable effect their response to the south end of Elks Lane every time if their standard response routes are followed. The Police Department also is able to more easily traverse through traffic if required to drive around on Higuera St. to get to the correct side of the creek, once again minimizing the impact on response time. I clocked the driving times using both routes in a simulated non-emergency response from the intersection of Higuera and Elks to the Mobile Station at Prado and Elks. Utilizing Higuera St. s/b to Prado Rd and then Prado Rd. to Elks Ln. , I clocked two different times. The first response was 1 minute, 16 seconds and the second was 1 minute and 14 seconds. I then clocked the response time from Higuera and Elks to the same Mobile Station, this time utilizing the direct Elks Ln. route. The first time was 43 seconds and the second time was 44 seconds. The net results indicate a 32 second difference in response time using the two different routes. My test was conducted at 1130 A.M. on a Thursday with a top speed of 45 mph and no lights or siren activated. I next checked through CRIS for the number and type of incidents that we have responded to during the last three years involving Elks Ln. I located several incidents, most of which involved Z -Z3 traffic stops at Elks and Higuera or Elks and Prado. Of the incidents located, only one involved an emergency response (injury collision at 333 Elks) . Conclusion: Based on the information that I have discovered, the removal of the Elks Lane bridge probably would not significantly impact the Police Department. Had the bridge been removed during the last three years, police response time to only one incident may have been effected. The degree to which the response may have been effected would depend upon the location from which the officer responded from. Even if the officer would have had to respond from the "wrong side" of the creek, his response time would have likely been increased by approximately 30 seconds. Please bear in mind that my conclusions only address police issues. The Fire Department makes up the other half of the public safety picture and their concerns may be justified when examined from their perspective.