tide level 5 in the river 2 and reduce the size of the sand bar 11 fig2 also depicts the inventive system 1 deployed in a tributary canal 14 that has a sand bar 11 near the entrance of the tributary canal 14 to the river 2 the marine vessel 4 would be anchored in the tributary canal 14 pointed against the canal water flow 10 by powering the vessel 4 through the engines 12 and propellers 6 water as shown by the prop wash 7 will be forced back the canal 14 to lower the tide level 5 in the river 2 and reduce the size of the sand bar 11 fig3 depicts a plan view of the failure of the flood walls 21 at the 17 th street canal 19 in new orleans during hurricane katrina a breach 23 in the floodwall 21 occurred on the orleans parish side of the canal 19 opposite the jefferson parish side also shown is a bridge 17 and road 18 the breach 23 allowed floodwaters 24 to wash out the mud and clay levee 22 completely flooding and destroying residences along the side of the canal 19 the canal 19 empties into lake ponchartrain 15 at the time of this flooding the canal water level 20 was plus 15 feet as was the lake water level 16 these water levels were well above the elevation of the breach 23 so the flood water 21 continued to flood new orleans fig4 has the same plan view as shown in fig3 but with the inventive tidewater control system deployed.