1 2 COLUMBIA LOCK AND DAM PROJECT INFORMATION OUACHITA-BLACK RIVER 237 217 200 80 252 237 217 200 119 174 237 217 200 27 .59 N 255 0 163 131 239 110 112 62 102 130 255 0 163 132 65 135 92 102 56 120 255 0 163 122 53 120 56 130 48 111 Ryan Reves, P.E. Dam Safety Program Manager Vicksburg District “The views, opinions and findings contained in this report are those of the authors(s) and should not be construed as an official Department of the Army position, policy or decision, unless so designated by other official documentation.” 3 4 PROJECT INFORMATION PROJECT INFORMATION N N
5 6 PROJECT INFORMATION 2015 ISSUES • Issue first discovered N November 2015. Entry • Lock master saw a plume of material inside the lock Sand chamber. Boil Flow • Performed multi-beam survey of the project. • Lock closed to navigation for repairs Entry Lock width: 84 ft. Upper Miter Gate Useable length: 600 ft. Provides 18 ft. of lift Sand Normal upper pool elevation is 52.0 ft. (NGVD) Boil Normal lower pool elevation is 34.0 ft. (NGVD) 7 8 2015 ISSUES 2018 MULTI-BEAM SURVEYS • Multi-beam survey taken at end of January 2018 revealed the issue has • Temporary repair designed, installed, and completed migrated. by December 2015 allowing navigation to continue. • Received funds to design • District budgeted and requested funds to design a repair permanent repair. • Performed seepage study • Request included funds for: in February/March. • Seepage study • Drilling / installation of relief wells
9 10 EXPLORATORY DRILLING PROJECT INFORMATION • Seepage study is completed. • June 2018 Incorporating findings from study, preparing to perform exploratory drilling in advance of installing relief wells. Lock cross-section • These voids are not supposed to be here. • Completely changed our understanding of the progression of the situation. 11 12 DS SAND BOIL PROBING DS SAND BOIL DS Miter Gate • Declared Dam Safety Emergency DS Miter Gate in July 2018, closed off navigation, and lowered upper pool. • Immediately began designing emergency repair and developing P&S. • Tabletop meeting held in July with surrounding communities, ORVA, industry, and local stakeholders to communicate the issue and impacts. Downstream approach slab • It is now obvious that the situation is not constrained to within the lock chamber only. Approx. 5ft void • Issue can no longer be managed by manipulation of the chamber pool. Sand Boil View looking upstream
13 14 ISSUES / REPAIRS FINDING A CONTRACTOR • Sand Boils • Exploratory Drilling • Voids Under Wall • Sheet Pile • Void in Chamber Floor • Coring • Market research identified 6 technically capable contractors. • Grouting / Tremie Concrete • Relief Wells • Floor Repair • Many of the prime contractors were not interested in the work due to: • Complexity of work • Uncertainty of work in underwater conditions • Need for a quick turn-around to open project back for navigation • Engineering During Construction (EDC) flexibility to modify plans/specs in the Sheet pile midst of changing conditions cutoff wall Cored grout holes • Massman Construction Co. won the bid as the general contractor Entry hole and void Cored grout holes used to inject grout / tremie concrete Sheet pile cutoff wall Entry hole and void 16 15 CURRENT STATUS WHEN WILL IT BE COMPLETE? Area 5 (Downstream Approach Slab) • Holes drilled • Some grout work remaining • Seal joint between slab and sill • End of April is targeted for completion. • High river could push completion in early to mid May . Area 4 (Downstream Poiree/Gate Sill) • Holes drilled • Final grout quantities and lock floor repairs will drive final • Some grout work remaining completion date. Area 6 (Lock Floor) • Pending modification • Relief well lateral drain installation and repair in front of Area 3 (Landside Lock Wall ) • Relief wells installed Area 7 (Riverside Lock Wall) tainter gate are water level dependent. • Laterals to be installed • COMPLETE • Holes drilled and grouted • Exploratory drilling complete • Handful of heel holes to completed • No voids found WHEN WILL PROJECT BE OPEN? Area 2 (Upstream Poiree/Gate Sill) • COMPLETE Area 8 (Tainter Gate #1) • Holes drilled • Opening for navigation could be as early as end of May. • Scour hole repairs delayed by • Grout placed river stages • Drain installation and repair in front of tainter gate not Area 1 (Upstream Approach Slab) expected to delay opening the project. • COMPLETE • Sheet Pile Installed • Slab drilled • Grout placed
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