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ABALONE COVE LANDSLIDE ABATEMENT DISTRICT (ACLAD). Board of Directors Sharon Nolan Mary Sheridan Neil Siegel Emily Vaughan Robert Douglas, Chairman Mgr. Well Operations Daphne Clark Secretary Sandy Marshall. ABALONE LANDSLIDE ABATEMENT DISTRICT (ACLAD).
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ABALONE COVE LANDSLIDE ABATEMENT DISTRICT (ACLAD) Board of Directors Sharon Nolan Mary Sheridan Neil Siegel Emily Vaughan Robert Douglas, Chairman Mgr. Well Operations Daphne Clark Secretary Sandy Marshall
ABALONE LANDSLIDE ABATEMENT DISTRICT (ACLAD) • Geological Hazard Abatement (GHAD) District • created by the Beverly Act (SB1195) of l979; ACLAD was the first district formed (1981) • Governed by a Board of Directors (5 persons) elected from property owners in the District • Assisted by a Secretary and Manager of Well Operations • ACLAD assesses property owners in the district to pay for construction and maintenance of abatement measures • Example: Dewatering wells • GHADs are a means by which homeowners can “help themselves”
GROUNDWATER AND LANDSLIDES Head FRACTURES/FISSURES - CONDUITS FOR INFLITRATING WATER Toe SLIDE SURFACE (IMPERMEABLE LAYER) GROUNDWATER BUILDUPS WITHIN LANDSLIDE Rain • RESULT: • INCREASE WEIGHT • INCREASE PORE • PRESSURE • MOVEMENT Abalone Cove Landslide ? TRAPPED WATER Altamira Shale Basalt
WW15 WW12 ACLAD Dewatering Wells 2006 WW13 WW16 WW1 WW14 WW6 WW8 WW11 WW7 WW17 WW3 WW10 WW4 WW2 WW9 WW5 Abalone Cove Landslide WW19 1980 wells WW20 WW18 Wells added after l985
Well Production 1980-2006 Aver. Production approx.150,000 gals/day First wells drilled Upslope wells added (Aver. daily production for February and September)
>20,000 gal/day >6,000 gal/day 1-6,000 gal/day <1,000 gal/day WW15 WW12 WW13 WW16 WW14 WW6 WW1 WW11 WW8 WW7 WW17 WW3 WW2 WW4 WW9 WW5 Abalone Cove Landslide WW19 WW18
Major Maintenance Project WW1 WW6 WW3 ACLAD Original set of wells 1980-81 WW2 REDRILL WW5 Proposed Abalone Cove landslide Completed
RAINFALL WELL PRODUCTION Aver=15 in/yr WET YEARS RAINFALL AND WELL PRODUCTION DRY YEARS
RAINFALL AND MOVEMENT IN THE ABALONE COVE LANDSLIDE CREEP (mm/yr rate) WET YEARS RAINFALL THRESHOLD 21-23 in/yr ENSO cycles (5-8 yrs) DRY YEARS
INCREASE RAINFALL WITH ELEVATION Highly Developed 40% increase Sparsely Developed
SUMMARY • ACLAD Dewatering wells currently pumping ~ 200,000 gals/day; nearly 300 acre-feet water annually • Since l980, water table elevations have dropped: • 25-60+ feet in Abalone Cove Landslide wells • 8-10 feet in upslope well • Creep (mm/yr rate) in Abalone Cove Landslide occurs when rainfall totals >~22 inches/year • Need to rehab older wells and drill new wells in upslope areas (wet years)
ABALONECOVE LANDSLIDE ABATEMENT DISTRICT (ACLAD) 1980-2006: TWENTY-SIX YEARS OF PROGRESS AND SERVICE • DEWATERING WELLS • GPS MEASUREMENTS
WW15 ACLAD Production Wells 2006 WW12 WW13 WW16 WW14 WW6 WW1 WW11 WW8 WW7 WW17 WW3 >20,000 gal/day >6,000 gal/day WW2 WW4 WW9 1-6,000 gal/day WW5 Abalone Cove Landslide WW19 <1,000 gal/day WW18