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HomeMy WebLinkAboutMINUTES - 11071989 - 2.7 07 7 TO: BOARD OF SUPERVISORS, AS THE GOVERNING BODY OF CONTRA COSTA COUNTY FLOOD CONTROL AND WATER CONSERVATION DISTRICT FROM: J. MICHAEL WALFORD, CHIEF ENGINEER DATE: NOVEMBER 7, 1989 SUBJECT: OCTOBER 10, 1989 REFERRAL - MARSH CREEK WATERSHED Specific Request(s) or Recommendation(s) & Background & Justification I. RECOMMENDATION ACCEPT report of the Chief Engineer on the status of the Marsh Creek Watershed Study Environmental Impact Report and the staffs interaction with City and County government to insure that adequate drainage infrastructure is installed during the development process. II. FINANCIAL IMPACT Considerable future costs will be incurred if necessary drainage infrastructure is not installed as a part of the development process. Continued on attachment: yes Signature: �� Recommendation of County Administrator Recommendation of Board Committee Approve Other: Signature(s) : Action of Board on: November 7, 1989 Approved as Recommended X Other X REQUESTED staff to meet further with concerned residents. Vote of Supervisors I HEREBY CERTIFY THAT THIS IS A TRUE AND CORRECT COPY OF AN X Unanimous (Absent I & IIIA) ACTION TAKEN AND ENTERED ON Ayes: Noes: THE MINUTES OF THE BOARD OF Absent: Abstain: SUPERVISORS ON DATE SHOWN. Attested November 7, 1989 Orig. Div. :Public Works (FCE) cc: County Administration PHIL BATCHELOR, County Counsel CLERK OF THE BOARD Community Development Director OF SUPERVISORS AND City of Brentwood - via PWD COUNTY ADMINISTRATOR Public Works Director A Accounting By cy, Q,,aa JJjjaA; Flood Control G. Dickey DEPUTY CLERK A.B. McNabney MFK:jo:ly bo:7 .tll Marsh Creek Watershed November 7, 1989 Page 2 III. REASONS FOR RECOMMENDATION/BACKGROUND For several years, staff has recognized that continued urbanization in the Marsh Creek Watershed would result in future flooding if additional drainage infrastructure was not installed as a part of the urbanization process. The watershed is presently served by the Marsh Creek Watershed Work Plan improvements constructed by the U.S. Department of Agriculture Soil Conservation Service in the mid 1960 ' s. These improvements were based on an agricultural land use, and they provide only a 50 year level of protection. New development in the watershed dictates that the level of protection be increased to the 100 year level consistent with the Federal Flood Insurance Program and that the existing improvements be modified or supplemented to accommodate the increase in runoff from additional urbanization. The Marsh Creek Watershed Study being conducted by staff will assess the impacts from future urbanization as envisioned in the present General Plans for the area. The Study will present and discuss plan alternatives if the level of development ever exceeds that envisioned under the current general plans but the improvements are sized to only accomodate the urbanization currently provided for. The alternative solutions being evaluated utilize detention basins and flood plain type channels to minimize the environmental impact. These concepts are consistent with the preferred methods expressed in the new draft County General Plan. We expect the study and related draft environmental impact report will be ready for public review in February 1990. The Marsh Creek Study report and Environmental Impact Report will provide the basis for the Board to adopt regional drainage plans for the watershed and corresponding drainage fee ordinances to equitably spread the cost of needed drainage infrastructure to all of the developing properties. This document will also provide the basis for Flood Control District acquisition of the necessary rights of way for the various projects and construction of some of the facilities. While our study has been in progress, several parcels in the City of Brentwood have been proceeding through the City' s development process. To insure that these developments install their fair share of the needed future infrastructure and to ensure that these developments protect themselves from flooding from Marsh Creek and its tributaries, we have recommended to the City of Brentwood that they require each development to install drainage improvements as a part of the development approval process. Failure on the part of the City to require adequate drainage with each development could result in several hundred homes being subject to flooding in the future. It should be noted that each development being processed by the City has complied with the necessary California Environmental Quality Act requirements. On October 18 , 1988 , the Board directed staff to "re-initiate the CEQA process for the Marsh Creek Watershed Study, including the participation of all parties involved, and in due course report to the Board on same" . We have commissioned the preparation of a draft Environmental Impact Report (EIR) to address the various project alternatives, and we have had some meetings with the Brentwood City Council and various property owners affected by the alternatives. Additional meetings will be held in the community during the plan and draft EIR review process. We do not believe that the absence of a completed EIR on the Watershed Study should prevent staff from sharing its concerns on drainage matters related to ongoing development in the watershed. Marsh Creek Watershed November 7, 1989 Page 3 The October 10, 1989 letter from Mr. Gene Dickey contains several errors and misconceptions. He indicates that the ultimate plan will require the excavation of 30, 000, 000 cubic yards of material while in reality the plan will probably only require 1, 500, 000 cubic yards of excavation. He indicates that the material has a value of $3 . 00 per cubic yard and that County staff plans to give away this valuable commodity. This is not true. The three subdivisions will collectively excavate less than 20, 000 ' cubic yards, and the material has no value when you consider the cost of loading the material and trucking it from Brentwood. The cheapest method of construction of these channel improvements is to use heavy construction equipment to perform the excavation and for the material to be wasted in the adjacent subdivision lot pads. To the best of our knowledge the work being performed by subdivisions 6800, 7009 , and 7276 in the City of Brentwood is consistent with their approved development condition of approval .