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HomeMy WebLinkAboutMINUTES - 08061996 - C32 TO: BOARD OF SUPERVISORS, AS GOVERNING BOARD OF CONTRA COSTA COUNTY AND CONTRA COSTA COUNTY FLOOD CONTROL AND WATER CONSERVATION DISTRICT FROM: J. MICHAEL WALFORD, CHIEF ENGINEER DATE: AUGUST 6, 1996 SUBJECT: WILDCAT CREEK SEDIMENT BASIN MAINTENANCE, SIERRA CLUB ET AL LETTERS, BOARD REFERRAL JULY 23, 1996, ITEM C.79 SPECIFIC REQUEST(S)OR RECOMMENDATION(S)&BACKGROUND AND JUSTIFICATION I. Recommended Action: A ACCEPT report from the Chief Engineer and a separate report from the Coalition to Restore Urban Waters, acknowledging disagreement and direct all interested parties to continue to work toward a mutually agreeable solution regarding the controversy over District's proposal to remove sediment from the Wildcat Creek Sediment Basin as required by the approved Operation and Maintenance Plan for the Wildcat and San Pablo Creeks Project; and B APPROVE Chief Engineer's offering to allow the volunteer vegetation on the sediment basin floor within 50-feet of the south bank to remain until September 1, 1997, to provide time for the Corps of Engineers or the Coalition to develop a replacement sedimentation basin configuration that is equivalent in all respects to the basin originally designed by the Corps of Engineers and provides a shaded, maintainable, low flow channel for fish passage; and C CONCUR with staffs plans to desilt this fall the other areas of the sediment basin outside ,the limits of the 50-foot wide corridor of volunteer vegetation. D ADOPT the attached resolution to the Corps of Engineers indicating the District's desire that the sediment basin be redesigned to provide for a shaded fish passage facility that is functional without excessive low flow reestablishment work each year and the District's reluctance to accept Contract 3A (Wildcat Creek) until said ctive action is approved for construction. Continued on Attachment: X SIGNATURE: _RECOMMENDATION OF COUNTY ADMINISTRATOR _RECOMMENDATION OF BOARD COMMITTEE APPROVE OTHER SIGNATURE(S): ACTION OF BOARD ON NG p 6 1996 APPROVED AS RECOMMENDED OTHER_ VOT OF SUPERVISORS UNANIMOUS (ABSENT ) AYES: NOES: ABSENT: ABSTAIN: MFK:drg t Nereby eef*that thla b a true and coned am of \admin\milt\bo6.t8 an action taken and entered on the minuMa of-tM 9 floard of SuPiN The date shown. ATTESTED: Orig. Div: Public Works(ADMIN) PHIL BATCHELOR,CIe board Contact: Milton Kubicek(313-2203) ofSupervlsorsand County AO*MW&lot cc: CAO , County Counsel o A. ��ospuv V.Alexeeff,GMEDA J.Cutler,CDD M.Walford,Admin G. Connaughton,Mtce. continued last page Wildcat Creek Sediment.Basin Maintenance, Sierra Club et al letters, Board Referral July 23, 1996, Item C.79 August 6, 1996 Page Two E CONCUR with staff's position to not accept any modification to the sedimentation basin originally designed by the Corps of Engineers or the original maintenance plan that will result in higher maintenance costs without first obtaining approval from the Board. II. Financial lmpact: Decreasing the size of the sedimentation basin will increase the long term maintenance costs for Wildcat Creek through more frequent sediment removal, more sediment bypassing the basin, and increased difficulty in handling the sediment to be removed. The costs could be in the tens of thousands of dollars. With the loss of Special District Augmentation Funding, maintenance costs for Wildcat and San Pablo Creeks must be funded from the County's Stormwater Utility Area No. 17 (unincorporated area) revenues. III. Reasons for Recommendations and Background: Staff has been in consultation with Ms. Ann Riley, Coalition to Restore Urban Waters, for over a year regarding the volunteer vegetation on the sediment basin flow. According to the Wildcat Creek Master Plan, Mitigation Plan, and Operation and Maintenance Plan, no vegetation was envisioned in the basin floor area due to the known need for periodic removal of sediment from the sediment basin. The basin cross section was to be maintained as shown in Section 96+25 Plate 3, sheet 12 of 40 attached. This Section has an "n" value of .04 to .042 which, according to the sediment removal guidelines for Section 96+25 Exhibit G, sheet 36 of 40 of the Maintenance Manual, allows sedimentation accummlation of up to two feet of depth in the basin before it must be desilted. Unfortunately, the cross section Station 96+25 of the sediment basin looks like Plate 3, sheet 28 of 40. The large, dense vegetation yields a value of n=0.070 which is unacceptable according to the freeboard reduction curves in Exhibit G, sheet 36 of 40. Also attached are plan sheets 3 through 6 of 10 from the Maintenance Manual which shows the approved mitigation plan for Wildcat Creek. The sediment basin was constructed, at considerable local cost, as a mitigation measure to trap sediment upstream of the mitigation planting area to reduce the need for sedimentation removal activities within the mitigation area. Failure to control the sediments in Wildcat Creek will increase the need for sediment removal along the entire improved portion of Wildcat Creek at a significant increase in local cost and considerable environmental damage. Any sediment removal work within the mitigation area, even if it is warranted by the approved maintenance plan, is going to meet significant public objection. It is imperative that the sedimentation basin function as originally envisioned. Failure to do so could ultimately result in degradation of the new flood protection. Sheet 6 of 10 shows the sediment basin area. Note that the plan shows no vegetation on the basin floor. On the next sheet, 6A, the extent of volunteer vegetation has been indicated. The cross hatched area is the area where vegetation is to remain until September 1, 1997 by the proposed letter agreement with the Coalition to Restore Urban Waters. The sediment basin design by the Corps of Engineers did not adequately address creation of a perpetual low flow channel for fish passage. The low flow channel constructed by the Corps of Engineers fills in with sediment each time a significant rain event occurs. Reestablishing the low flow channel each year is not practical. The task is complicated by the absence of adequate access and the saturated condition of the soil. The Corps of Engineers' plan provides for fish passage along the entire length of the improved creek, except through the sedimentation basin. We recommend that the Corps of Engineers be requested to correct this deficiency. Engineers for the Coalition to Restore Urban Waters have suggested that the basin may be adequate even with the volunteer vegetation remaining. Staff does not recommend any decrease in the sediment storage area to further enhance vegetation on the project. At best, decreasing the storage volume increases our long term maintenance costs by requiring more frequent removal work. At worst, it reduces the efficiency of the basin to trap sediments thereby accelerating the deposit of sediments downstream in the environmentally sensitive areas. C, 3;L., ..Wildcat Creek Sediment Basin Maintenance, Sierra Club et al letters, Board Referral July 23, 1996, Item C.79 -August 6, 1996 Page Three cc: Congressman George Miller 367 Civic Dr#14 Pleasant Hill, CA 94523 Assemblyman Tom Bates State Capitol P. O. Box 942849 Sacramento, CA 94249-0001 Ann Riley, Executive Director Carole Schemmerling Coalition to Restore Urban Waters 1250 Addison, Suite 107 Berkeley, CA 94702 Larry B. Fishbain 913 Cerrito Street Albany, CA 94706 Lillie Mae Jones Community Youth Council for Leadership and Education Cycle 258 6th Street Richmond, CA 94807 Norman La Force, Chair Sierra Club, SF Bay Chapter 5237 College Avenue Oakland, CA 94618 Paul Bowers Mark Boedtker John N. Reese, Colonel USA COE 1325 J Street Sacramento, CA 95814-2922 Margaret A. Roper Brian Hunter Department of Fish & Game P. O. Box 47 Yountville, CA 94599 Tim Vendlinski Environmental Protection Agency 75 Hawthorne Street San Francisco, CA 94105 Ken Burger East Bay Regional Parks 2950 Peralta Oaks Ct. Oakland, CA 94605-0381 Mr. Pat O'Brien East Bay Regional Parks District P. O. Box 5381 Oakland, CA 94605-0381 Barbara Vincent 2500 Lowell Ave. Richmond, CA 94804 THE BOARD OF SUPERVISORS, CALIFORNIA AS THE BOARD OF SUPERVISORS OF CONTRA COSTA COUNTY AND AS THE GOVERNING BODY OF THE CONTRA COSTA COUNTY FLOOD CONTROL AND WATER CONSERVATION DISTRICT Adopted this Order on August 6, 1996 by the following vote: AYES: Supervisors Rogers, Bishop, DeSaulnier, Torlakson, Smith NOES: None ABSENT: None ABSTAIN: None RESOLUTION NO 96/351 SUBJECT: WILDCAT CREEK SEDIMENT BASIN MAINTENANCE, NORTH RICHMOND AREA Project # 7527-6D8601 WHEREAS the Corps of Engineers has constructed flood control improvements on Wildcat Creek that are multipurpose: flood control, environmental enhancement, and recreational,; and WHEREAS one of the environmental features is the creation of a vegetation shaded low flow channel to promote fish passage; and WHEREAS the Corps of Engineers has expended considerable monies to install a fish ladder in the concrete channel under the Southern Pacific Railroad tracks; and WHEREAS the Corps of Engineers low flow fish passage channel constructed across the sedimentation basin is obliterated by sedimentation deposits each time it rains; and WHEREAS said low flow channel cannot reasonably be maintained functional; and WHEREAS without a functional low flow channel across the sedimentation basin, the millions of dollars spent on the project to include environmental enhancements and a channel for fish passage will be for naught. NOW THEREFORE BE IT RESOLVED by this Board that the Corps of Engineers is requested to redesign the sedimentation basin to provide a separate fish passage channel through the sediment basin; and BE IT FURTHER RESOLVED that this Board is reluctant to accept Contract 3A\/ViIdcat Creek for maintenance until the fish passage through the sediment basin issue is successfully resolved. I lierelry oaeiN Md tAb b s hss and oonrl�t a0py 01 f�perdtaandnOmd no SUpeivtgam a►th date shownmbubs ai tlM ATTESTEq: i PHIL BATC LOR,Clerk Offt board of Supervisors and County AdminlatraW ti ��.oeaair MFK:drg l g1adminlmilt1res6.t8 Orig.Dept.: Public Works(AD) Contact Person: Milton Kubicek € cc: See next page RESOLUTION NO. 96/351 WILDCAT CREEK SEDIMENT BASIN MAINTENANCE, NORTH RICHMOND AREA Project # 7527-6D8601 August 6, 1996 Page Two cc: CAO County Counsel V. Alexeeff, GMEDA J. Cutler, CDD M. Walford, Admin. G. Connaughton, Mtce. Congressman George Miller Assemblyman Tom Bates State Capitol P. O. Box 942849 Sacramento, CA 94249-0001 Ann Riley, Executive Director Carole Schemmerling Coalition to Restore Urban Waters 1250 Addison, Suite 107 Berkeley, CA 94702 Larry B. Fishbain 913 Cerrito Street Albany, CA 94706 Lillie Mae Jones Community Youth Council for Leadership and Education Cycle 258 6th Street Richmond, CA 94807 Norman La Force, Chair Sierra Club, SF Bay Chapter 5237 College Avenue Oakland, CA 94618 Paul Bowers Mark Boedtker John N. Reese, Colonel USA COE 1325 J Street Sacramento, CA 95814-2922 Margaret A. Roper Brian Hunter Department of Fish &Game P. O. Box 47 Yountville, CA 94599 Tim Vendlinski Environmental Protection Agency 75 Hawthorne Street San Francisco, CA 94105 Ken Burger East Bay Regional Parks 2950 Peralta Oaks Ct. Oakland, CA 94605-0381 Mr. Pat O'Brien East Bay Regional Parks District P. O. Box 5381 Oakland, CA 94605-0381 Barbara Vincent 2500 Lowell Ave. Richmond, CA 94804 RESOLUTION NO.96/351