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HomeMy WebLinkAboutAGENDA REPORT 1992 0401 CC REG ITEM 08IITEM 2 • � MOORPARK 799 Moorpa.* Avenue Moorpark, California 93021.. (805 5295864 4., ._ 1992- -T;ON M E M O R A N D U M TO: The Honorable Planning Commission Works M: Kenneth C. Gilbert, , Director of Public DATE: March 11, 1992 (Commission Meeting 4 -1 -92) SUBJECT: Consider Authorizing a Study of the Spring Road Bridge OVERVIEW This requests authorization to proceed with a study to evaluate the Spring Road bridge. In the past the City Council has discussed the inadequate width of the Spring Road bridge and the feasibility of modifying the bridge to better accommodate pedestrian and bicycle traffic. The question of adding two additional vehicle travel lanes has also been discussed. In light of recent events, this requests clarification of future direction with respect to the disposition of the bridge. DISCUSSION The Spring Road bridge was constructed by Caltrans (old Route 23) in 1952. A copy of the bridge design plans are being sent to the City by Caltrans. As you may be aware, the bridge is supported by a number of piles placed in the middle of the arroyo Simi. During the recent storms a considerable amount of debris (including large trees) did not pass under the bridge, but instead collected on these bridge support piles. This debris obstructed the flow of storm water under the bridge. At one point the storm water flows were splashing over the top of the bridge. The volume and velocity of the storm water flows exerted a great deal of lateral force PAUL W. LAWRASON JR. BERNARDO M. PEREZ SCOTT MONTGOMERY ROY E. TALLEY JR. JOHN E. WOZNIAK Mayor Mayor Pro Tern Councilmember Councilmemaer Councilmember Spring Road Bridge Page 2 against the debris and the bridge support piles behind the debris. Although staff was not sure what amount of lateral force the bridge could have withstood, staff was fearful that the bridge was in danger of being damaged or destroyed. Although the bridge survived this event, staff remains fearful that the bridge is in danger of sustaining future damage from a severe storm. It became apparent from this episode that the Spring Road bridge design is incompatible with the volume and character of storm flows during a severe storm. The volume of storm water run -off in 1952, when this bridge was constructed, was much less than it is today. It is possible that this bridge design was compatible with the nature and character of storm flows at that time. The volume of storm water and, more importantly, the amount of large trees and debris generated in the Arroyo Simi has increased dramatically: This matter was recently discussed by the Public Works / Facilities Committee. It was their recommendation that the City Council consider having a study prepared to evaluate the present condition of the bridge, and the possible options to considered regarding retaining and /or reconstructing the bridge. The following is a list of the types of questions and analysis such a study would address: • an evaluation of the present condition and function of the Spring Road bridge; • the review of Ventura County Flood Control District design standards and criteria for this segment of the Arroyo; • the review of prior City actions, such as the Calrlsberg Specific Plan, pertaining to bridge design elements (i. e., travel lanes, bike lanes, pedestrians, etc.); • a discussion of various design parameters, including a discussion of a design for a two lane bridge which can accommodate future expansion to four lanes; • the development of alternative recommendations pertaining to the possible need for the modification and /or reconstruction of the bridge (including a do nothing alternate; • the development of cost estimates for each alternate discussed; and, Spring Road Bridge Page 3 an analysis of the available funding sources for such a project, including Spring Road and Tierra Rejada AOC funds and other possible sources. RECOMMENDATION It is the recommendation of staff and the Public Works / Facilities Committee that the City Council authorize staff to proceed with the above described study. If approved, it is the recommendation of staff that Proposal be requested from the City Engineer and other qualified Civil Engineering firms.