( CNN ) -- Dramatic satellite images show large deposits of sediment in coastal Louisiana , the receiving end of the massive flooding on the Mississippi River . The sediment gush has a down and up side in region known for its seafood and delicate wetlands , a federal official said Friday . The U.S. Geological Survey ( USGS ) and NASA recently provided the stark imagery of the sediment plumes to the U.S. Army Corps of Engineers and Louisiana to assist them with flood response . See flooding map from USGS . A map on the USGS website allows users to call up the plumes and see flood data collected by government agencies . The opening of the Bonnet Carre spillway caused a sediment plume in Lake Pontchartrain above New Orleans . Another plume resulted from the opening of the Morganza Spillway and flooding on the Atchafalaya River . The third is where the Mississippi River meets the Gulf of Mexico . `` We live in historic times , '' said Phil Turnipseed , director of the USGS 's National Wetlands Research Center in Lafayette , Louisiana . The tan and brown plumes resulted from millions of gallons of sediment-laden freshwater rushing to the Gulf through spillways , river channels and levees . Wetland seasonal flooding `` is essential to the health of coastal wetland ecosystems , '' according to the USGS . Extreme flooding that has occurred this year has delivered high amounts of sediment and nutrients . The sediment will hurt the oyster harvest in the brackish waters of Lake Pontchartrain , essentially a bay , Turnipseed told CNN . `` All of this is temporary , '' he said . `` Eventually , Pontchartrain will cleanse itself . '' Flooding in the Atchafalaya basin has not been as severe as expected after officials opened the Morganza Spillway , but Turnipseed acknowledged it has affected residents . Across Louisiana , officials are still coping with the crisis . The Louisiana Governor 's Office of Homeland Security and Emergency Preparedness said Thursday that at least 1,230 structures in 13 parishes have been affected by floodwaters . Friday , it said 1,150 National Guardsman continue to be mobilized for the flooding response . For the Atchafalaya wetlands , the flooding is a plus because it will create desperately needed land , Turnipseed said . Gulf Coast hopes for busy Memorial Day . `` If the marsh grasses could sing , they would be singing praises , '' the official said . The sediment pushing through the mouth of the Mississippi is good for flood control , Turnipseed said , `` but it 's not a good thing for the ecosystem . '' Officials are undergoing the laborious of measuring and analyzing the sediment . Ecologists lament the sediment reaching the gulf , rather than building wetlands , which protect Louisianans from storm surge and support aquatic life . Over the past 80 years , the state has lost coastal wetlands equaling the size of Delaware , federal officials say . `` It 's a national tragedy , '' Turnipseed said . `` The wetlands are needed . '' The problem is not new . Natural processes and human disturbance , including dredging and pollutants , have taken their toll . Turnipseed on June 2 will present at the state Capitol a map of Louisiana wetland losses and gains from 1932-2010 . He hopes the new map will help inform land managers and agencies on marsh restoration . Federal authorities , meanwhile , are in the process of closing portions of the Morganza Spillway as the swollen Mississippi River recedes . The spillway was opened May 14 to prevent the Mississippi from flooding New Orleans and Baton Rouge . The Corps of Engineers has closed five of 12 bays , public affairs specialist Ricky Boyett told CNN on Friday afternoon . The Corps said much as 1.2 million gallons ( 172,000 cubic feet ) per second had been pouring through the spillway , which diverted water through the Atchafalaya basin , but that number was down to 120,000 cubic feet per second later in the week . The high water has caused some flooding down the Atchafalaya . But the water levels `` continue to be lower than anticipated '' throughout the basin , Corps spokesman Ken Holder said this week . The river remained about five feet above flood stage Friday afternoon at Bayou Sorrel and about six feet over flood stage at Morgan City , on the approaches to the Gulf . But it was more than five feet lower at the town of Krotz Springs and about two feet below flood stage at Butte LaRose , about 20 miles south of the spillway .
Satellite images show large sediment deposits along Louisiana coast . Officials are concerned about the loss of wetlands across the state . Mississippi River flooding is having negative and positive impact .