2009-283B - Laserfiche WebLink

Home Browse Search

3. 4. 1 Project Close-out and Demobilization Procedures Following the completion of decanting and the removal of all residual ponded water from the basin via the weir discharge pipeline, the contractor must re-install the weir boards to a height sufficient to ensure that no stormwater discharges over the weir crest . Stormwater thus retained must remain within the basin until the FIND ' s designated site operator returns to perform a controlled release (Section 3 . 4 . 2) . To this end, before the contractor demobilizes from the site, the Project Engineer will determine the weir crest height required to ensure that no uncontrolled release of stormwater occurs following project close- out . This determination will reflect information specific to each placement operation at the IR- 14 facility including the bulked volume of the dredged material , the geometry of the deposition, and specific permit requirements that may be imposed to govern the control and release of stormwater from the IR- 14 facility . The contractor must then re-install the weir boards consistent with the procedures outlined in Section 2 . 3 . 2 . 1 and set all weir stacks at or above this elevation. The earlier removal of weir boards to decant the site may have resulted in some boards being destroyed (that is, cut out into sections or damaged such that they cannot provide an adequate seal when re-installed consistent with the procedures outlined in Section 2 . 3 . 2 . 1 ) . The contractor should then fabricate additional weir boards sufficient to reach the required elevation , plus additional boards to replace those that may become damaged during future stormwater releases . The contractor must then close the facility ' s weir discharge shut-off valve (Section 3 . 2 . 2), and verify and certify to the FIND that the valve remains fully closed and free from leaks. To facilitate the future release of stormwater from the basin, the contractor' s final task is to excavate a small sump immediately adjacent to one or more weir stacks . This sump will promote stormwater drainage within the basin to the weirs so that removal of one or more weir boards will allow the water to pass over the weir crest and continue to the ICWW, by gravity flow, through the permanent weir discharge pipeline as discussed below . 3. 4. 2 Stormwater Control following the Contractor 's Demobilization After the contractor completes his demobilization from the IR- 14 facility, responsibility for continued management of stormwater within the basin, as well as all other continuing site maintenance activities between successive dredging operations, resides with the FIND . To this end , the FIND ' s designated site operator will periodically return to the site to release stormwater as well as the accumulated drainage from the dredged material as it continues to consolidate under its own weight . - 18 -