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Oceana Dredged Material Mangagement Plan 5.13.2025Oceana Dredged Material Management Area City Council Briefing LJ Hansen, P.E. | May 13, 2025 1 What is a Dredged Material Management Area (DMMA)? •A DMMA (Dredged Material Management Area) is used for the long-term storage or disposal of dredged material. •Dredged material consists of silts, clays, and sand removed from the bottom of waterways. •DMMAs are crucial for effective management of dredged material and promoting positive environmental outcomes. •Today, the City utilizes the Whitehurst DMMA for disposing of dredged material. 2 Why we are here •Whitehurst DMMA is reaching its capacity •City staff submitted a Modification of Conditions to the existing Conditional Use Permit (CUP) for a Borrow Pit at 560 Oceana Boulevard to create a new DMMA •Planning Commission voted to deny the request on April 9, 2025 •Public Works is requesting City Council approval to modify the CUP at 560 Oceana Boulevard for a new DMMA at the meeting on May 20, 2025 3 Planning Commission Hearing, April 9, 2025 •Planning Commission voted 9-0 (1 abstained) to recommend denial of the modification of the CUP. •Denial reasons: •There are concerns that the material used to fill the pit (e.g., clay, silt, sand) will differ from the material that was excavated (mainly sand). •Even though the material will be tested before dredging,there are ongoing concerns about the potential leaching of contaminants into the subsurface. •Before considering any modifications to the CUP, the proposed east/south perimeter berm should be constructed to ensure stormwater runoff is contained. 4 ▪District 1: 3 projects ▪District 2: 4 projects ▪District 3: 10 projects ▪District 4: 0 projects ▪District 5: 4 projects ▪District 6: 0 projects ▪District 7: 3 projects ▪District 8: 11 projects ▪District 9: 2 projects ▪District 10: 12 projects Lakes/Canals Navigation SSD Legend:49 Dredging Projects Completed (2018 – 2024) 5 Whitehurst DMMA 6 Whitehurst DMMA MARCH 2025Whitehurst DMMA •31-acre site •Conditional use permit for filling the site was approved in 2007. •The site became operational in 2012 with a fill capacity of about 650,000 cubic yards. •Initial intended uses included •Private dredging •Stormwater lake dredging •City navigation dredging projects •Whitehurst DMMA is nearing capacity sooner than projected.7 Whitehurst DMMA Projections •Projected dredge volumes for the Neighborhood Navigation Dredging program adopted in 2011 were not part of the projected capacity calculations. •Citywide stormwater lake and canal dredging was accelerated due to flooding from Hurricane Matthew in October 2016. •~595,000 cy of dredged material placed in the DMMA as of January 2025. •Over 60,000 cy of lake and navigation dredging planned for calendar 2025/26. 8 New DMMA 560 Oceana Boulevard 9 Whitehurst DMMA 560 Oceana Blvd. •560 Oceana Boulevard •City Council District 6 •Zoned I-1 Light Industrial •19.50 Acre Site •Noise Zone – greater than 75 Db DNL •Currently an Inactive Borrow Pit (lake) •Requires a modification to the existing Conditional Use Permit (CUP) to fill the Borrow Pit New DMMA Location 10 560 Oceana Boulevard History •Prior to 1985, the site was used for agricultural purposes. 1958 11 560 Oceana Boulevard History (continued) •In 1985, a CUP was granted allowing the site to be used as an 11-acre borrow pit. •In 2001, an expansion of the borrow pit was approved, increasing the borrow pit size to 16.5 acres 2014 Oceana Blvd.12 560 Oceana Boulevard History (continued) •In 2016, excavation within the borrow pit was completed, and it remained a lake in accordance with the approved conditions. 2025 13 Why 560 Oceana Boulevard? Site was identified as a potential Dredged Material Management Area (DMMA) site due to the following: •Like the Whitehurst DMMA, it was a borrow pit and can provide capacity for City dredge projects. •The borrow pit is not a stormwater facility – it does not receive or discharge stormwater. It is an appropriate use. •It is in the same truck trip corridor as the Whitehurst DMMA (less than 2,000ft to the south). •Its proximity allows planned/future dredging projects to remain economical as trip distances will be similar. 14 560 Oceana Boulevard Site Acquisition •An agreement for the sale of the property was submitted to the City in December 2015 on behalf of the seller. •City Council approved the acquisition of the property by Ordinance dated January 19, 2016. •The purchase of the 19.5-acre site was finalized in March 2017. 15 Conditional Use Permit Process •May 9, 2018: Planning Commission voted 6-3 to modify the CUP (Borrow Pit - Fill). •May 22, 2018: City Council requested more information on well monitoring for stormwater and groundwater. •June 2018 to October 2024: Studies conducted on well water and stormwater runoff. •Feb 12, 2025: Planning Commission deferred the modification, seeking clarification on well water issues. •April 9, 2025: Planning Commission voted 9-0 (1 abstained) to recommend denial of the modification of the CUP. •April 14, 2025: Monitoring wells installed to address Planning Commission concerns. 16 DMMA Design •Fill capacity: approx. 350,000 cy (8-10 yrs) •Monitoring wells installed to address concerns raised by the Planning Commission •3 wells extend 30 feet below the ground surface to evaluate water seepage •Wells will determine the direction of groundwater flow and collect baseline samples to develop a monitoring program •Dredge material will be tested for contaminants before using the pit •A 2-3ft berm will be built on the east perimeter to provide additional storage during large rain events •Haul roads and ramps will be built before dredge placement operations start 17 Alternatives – costs impacts: •No other City-owned DMMA sites available to receive non-beach quality dredged material. •Local privately owned fill sites are available but are located at a +20mile one-way travel distance from most planned dredging projects. •Cost to dredge/haul/dispose to Whitehurst DMMA averages $53/cy. •Cost to private fill sites is about $140/cy. (Travel + Disposal) •Example: Project Contract Volume Low Bid Unit Price Dredge Price Private Fill Site Unit Price Dredge Price Percent Increase (%) Western Branch Lynnhaven River/Old Donation Creek Navigation Dredging* 50,479cy $52/cy $2,523,950 $140/cy $7,067,060 180% * Bids received in January 2025. Total bid price = $2.9Mil. Project will begin in May 2025. 18 Next Steps: •Request approval of modification to the CUP to allow filling at Oceana DMMA – May 20th. •If approved, site work will begin on the east perimeter berm and access roads. •Oceana DMMA to be operational by late fall 2025. •Current lake and navigation dredging projects can transition from Whitehurst DMMA to Oceana DMMA without disrupting their schedules. •PW Engineering staff will research future DMMA sites. 19 THANK YOU! Questions?