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CC SR 20241015 E - Landslide Emergency Contract Continuation CITY COUNCIL MEETING DATE: 10/15/2024 AGENDA REPORT AGENDA HEADING: Consent Calendar AGENDA TITLE: Consideration and possible action to reconfirm continuing the emergency justification for work and emergency contract for the Greater Portuguese Bend-Ancient Altamira Landslide Emergency Project. RECOMMENDED COUNCIL ACTION: (1) Reconfirm, by a four-fifths vote, there is a need to continue the work on the Deep Vertical Dewatering Emergency Project declared by Council-adopted Resolution No. 2024-20 on May 7, 2024, finding an emergency exists requiring immediate action in the Greater Portuguese Bend-Ancient Altamira Landslide Complex to seek to mitigate the movement of the landslide; and (2) Direct the City Clerk to confirm the same in the minutes of this City Council meeting, via Minute Order, reflecting this action. FISCAL IMPACT: There is no fiscal impact associated with the recommended Council action as the City Council appropriated $9,635,000 for emergency work outside the normal bidding process due to the emergency declaration. Additionally, as presented and approved on October 1, 2024, the City Council approved additional appropriations bringing the total to $32 million in FY 2024-25 as follows: VR • $24 million for emergency response which includes the $9.6 million approved on May 7, 2024 and $6.1 million on October 1, 2024. The $24 million includes, but not limited to, sewer repairs, fissure filling, road repairs, legal, equipment, personnel costs, district loans, tax assessments. • $4 million for emergency stabilization measures for deep dewater wells. • $4 million for winterization. FY 2024-25 Funding Sources $17.9M: • $10.1 million CIP (Fund 330) • $3.4 million General Fund (Fund 101) • $1.4 million Prop C (Fund 215) • $2.9 million ARPA (Fund 333) Additional FY 2024-25 Funding Sources $14.1M approved on October 1, 2024: • $500,000 ARPA (Fund 333) • $2.2 million Sup. Hahn Grant (General Fund - Grant 101) • $5 million CIP Emergency Reserves (Fund 330) • $6.4 million General Fund Excess Reserves (Fund 101) 1 Amount Budgeted: See Fiscal Impact Additional Appropriation: N/A Account Number(s): Account numbers TBD based on the above Fiscal Impact VR ORIGINATED BY: David Copp, Deputy Public Works Director REVIEWED BY: Ramzi Awwad, Public Works Director APPROVED BY: Ara Mihranian, AICP, City Manager ATTACHED SUPPORTING DOCUMENTS: A. October 1, 2024 staff report – Emergency Hydraugers Contract Continuation B. October 1, 2024 staff report – Consideration and Possible Action on the Greater Portuguese Bend-Ancient Altamira Landslide Complex C. August 20, 2024 staff report D. May 7, 2024 staff report E. Map of Effect of Deep Dewatering on Landslide (page E-1) BACKGROUND: On October 3, 2023, the City Council adopted Resolution No. 2023-47, declaring a state of local emergency relating to the land movement in the landslide complex. The state of emergency has been timely renewed and is current. On May 7, 2024, the City Council extended the Local State of Emergency pursuant to Resolution No. 2024-20 and approved, among other things, a Public Works Contract with Malcolm Drilling Inc. (Malcolm) to perform the work of the Portuguese Bend Landslide Emergency Hydraugers Project (Attachment D). On August 20, 2024, the City Council approved expanding the scope of the emergency hydraugers project and considering new alternatives including the installation of deep vertical dewatering wells (Attachment C). On October 1, 2024, the City Council approved expanding the scope of work to include winterization work and the installation of additional vertical deep dewatering wells (Attachment B). The City Council has reconfirmed the need to continue the work at its regularly scheduled meetings (Attachment A). DISCUSSION: Pursuant to Public Contract Code § 22050, the City Manager and Director of Public Works must report to the City Council at its regular meeting the reasons justifying why the emergency continues to exist and why action outside of the normal bidding process is 2 necessary to respond to the emergency. Furthermore, Public Contract Code § 22050 states that the City Council shall, at every regularly scheduled meeting , consider and reaffirm that there is a need to continue to remediate the emergency until the authorized emergency repairs have been completed. Accordingly, because the work has not yet been completed, this item is on tonight’s agenda. This item will be placed on each subsequent agenda until all aspects of the project are completed. Since the most recent update to the City Council on October 1, 2024, the need for the emergency work is ongoing. The status of the project at the time of publication of this staff report on October 8, 2024 is as follows: • 14 instrumented vertical test boreholes to characterize subsurface conditions and support the execution of dewatering operations have been installed . • Six vertical deep dewatering wells (DDWs) have been installed west of the Portuguese Bend Beach Club Community. The DDWs are currently discharging water at a combined rate of approximately 550 gallons per minute. This rate is lower than the prior week, which is expected as water pressure is reduced. • Three instrumented monitoring wells have been installed to gauge dewatering well performance in the area of DDW1-DDW6. Data from the monitoring wells shows that there continues to be a significant reduction in water pressure. • Deceleration rates in the areas of DDW1-DDW6 continue to be significantly greater than deceleration rates in other areas of the Landslide Complex, based on a sampling of GPS monitoring points. (Attachment E) • Installation of a seventh DDW is in process and expected to be complete this week. • Drilling of an additional instrumented vertical test borehole to site an eighth DDW is in process and expected to be complete by the end of this week. • Crews have mobilized for winterization of Altamira Canyon, which is expected to be completed in six to eight weeks. • Crews are preparing to mobilize for winterization of Portuguese, Ishibashi and Paintbrush canyons. A schedule for completion is being prepared. • Winterization of three sections of the Seaview community is expected to commence next week and be completed within approximately two weeks. • Environmental monitoring is being conducted in conjunction with construction activity. The emergency conditions necessitating the project continue to exist. CONCLUSION: The effects of the ongoing land movement continue to be felt in the Greater Portuguese Bend-Ancient Altamira Landslide Complex. Staff recommends reconfirming that there is a need to continue to remediate the emergency identified by City Council -adopted Resolution No. 2024-20 (originally by Resolution No. 2023-47), and reconfirm, by a four- fifths vote, the need for continuing the work on the Portuguese Bend Landslide Emergency Project. 3 ALTERNATIVES: In addition to Staff recommendation, the following alternative action is available for the City Council’s consideration: 1. Take other action or provide direction, as deemed appropriate. 4 35% 8.52”,5.55” 36%  7.05”, 4.5” 55% 6.6”, 3.0” 84% 1.34”, 0.21” 80% 2.88”, 0.57” 81% 3.6”, 0.69”  84% 7.95”,1.26” 83% 9.0”, 1.53” 81% 10.29”, 1.98” 80%, 11.46”, 2.34” 81% 10.65”, 2.04” 71% 8.34”, 2.46” 64% 9.24”, 3.36” 80% 8.64”, 1.74” 64% 10.11”, 3.63”55% 8.49”,3.78” 50% 9.75”,4.86” 53% 10.62”, 4.95” Effect  of Deep Dewatering Wells on Land Movement Between 9/4/24 and 10/7/24 Survey Points within  close proximity of  Dewatering Wells Deep  Dewatering  Well Numbers in boxes represent  percent decrease in surface  movement for the stated  time period. Red = rate on  9/4/24 and Black = rate on  10/7/24 in inches per week E-1