HomeMy WebLinkAboutOrange County Water District Heron Point Monitoring WellSunset Gap Seawater IntrusionInvestigationTri Ta, OCWD Director Div. 4Roy Herndon, Chief HydrogeologistAugust 10, 2020Seal Beach City Council
IntroductionOCWD Director Tri Ta•Seawater intrusion is a constant threat to our vital groundwater supply.•OCWD has been vigilant in controlling intrusion for decades.•This investigation will provide essential groundwater data.•Seal Beach is an important OCWD customer, and we thank you for your assistance in this investigation.
Orange County Water District (OCWD)•Manage & protect the OC Groundwater Basin•Basin supplies 77% of total water needs–19 municipal and special water agencies –2.5 million customers in north & central OC
TalbertBarrierAlamitosBarrierGeologic “gaps” provide underground pathways for seawater intrusion.
InvestigationFindings•Multiple potential sources and pathways•Extends 3 miles inland•300 feet deep•5 monitoring wells needed for further characterization
Proposed Monitoring Well SitesSeal BeachLeisure WorldNaval Weapons Station Seal BeachWestminster AveBolsa Chica RdMcFadden AveGraham StEdinger AveHeil AveWarner Ave
Gum Grove parking lot is the most viable well site. Gum Grove Parking Lot• Optimal location to assess suspected intrusion pathways–across Seal Beach Fault–beneath Landing Hill• Fills key data gap/complements other wells• Safe site off major streets• Avoids two-year permitting process with Navy
Gum Grove Park parking areaApprox. location of two proposed monitoring wellsSeal Beach Blvd
Anticipated Construction Layout and Summary•Sonic drilling method•Weekdays, 10-hour daytime only•Estimated 4-6 week activity duration at site•Estimated well depths:145 and 215 feetOne of two wells
Well Vault Completion andExpected Monitoring Frequency•Traffic-rated 12-inch diameter flush-grade vault•Water level measurements ~monthly•Water quality sampling ~2x/year
•Tonight’s City Council Briefing•Construction Fact Sheet (August 21, 2020)•Heron Pointe virtual meeting (September 9, 2020)•Communication with residents closest to construction•Communication with HOA Board of Directors•Construction Hotline•Notifications & construction updatesOCWD’s Community Outreach
Questions?Questions?Roy HerndonOCWD Chief Hydrogeologistrherndon@ocwd.com18700 Ward Street, Fountain Valley, CA 92708www.ocwd.com · @OCWDWaterNews