Robby Campo scrapes a canal bottom on the outskirts of Shell Beach, where he has an oyster lease.
"This place used to generate thousands upon thousands of oysters," Campo said of the surrounding area.
On a cold morning last week, Campo hit a dry hole. His dredge pulled up plenty of oyster shells, but ones that contained few oysters. Campo blames a small siphon at Violet for funneling too much fresh water into the marsh.
"Salinity here drops to two to three parts per thousand, four parts per thousand, you got dead oysters on your hands," Campo said.
More fresh water could be on the way as state and federal engineers study four possible sites for much larger diversions, two on each bank of the Mississippi River. The diversions, part of the state Coastal Master Plan, are envisioned by supporters as a key tool to rebuild and sustain marsh by delivering much-needed sediment to wetlands cut off from the river by levees.
"There are going to be impacts," said Jerome Zeringue, who left his job last week as chairman of the Louisiana Coastal Protection and Restoration Authority. "We don't deny the fact that there are shifts, but there are shifts that occur without doing anything."
Now, the state has begun a separate socio-economic study of the effects of the diversions, including its impact on oysters and other fisheries.
"It's something that should have been done a long time ago," said George Ricks of The Save Louisiana Coalition, a group of fishermen opposed to the diversions. "It should have been done in the early stage of planning and design."
Ricks also questioned the independence of the scientists conducting the study, which will include experts from LSU and the state-created Water Institute of the Gulf.
Zeringue insisted he has full confidence in the integrity and objectivity of those conducting the study.
"The folks that we've employed to do this are eminently qualified and capable," Zeringue said.
Zeringue said the study aims to conduct more than a simple cost-benefit analysis, including potential benefits from improved natural hurricane protection.
"The intent is to make things better, not make things worse," Zeringue said.
While diversions would drive salt water species away from the river, Zeringue said the study would aim to mitigate the harm, "so we can operate them in the most efficient and effective manner and also minimize any potential negative impacts."
It might also tell scientists and marine experts precisely where salt water species might find more favorable habitat in the wake of diversions, he said.
Although Louisiana's $50 billion master plan calls for several large diversions, supporters point out the state actually plans to spend about three times more delivering land by pipe through dredging.
However, supporters insist Louisiana's best hope for rescuing its disappearing coastline rests in mimicking the river that built the great Delta.
The science and engineering obstacles are many. Last year, state consultants presented the CPRA with cost estimates in the stratosphere for the planned Mid-Barataria Diversion on the west bank of Plaquemines Parish. The most elaborate construction plan topped $1 billion, about three times earlier estimates.
However, state officials have since talked of downsizing the diversion and believe the latest science offers the promise of achieving the same results with less river water.
Different construction techniques could also lower the cost, state officials have said.
A separate state-federal hydrologic study aims to answer questions about which of the four potential sites offers the best hope for land-building.
The new socio-economic impact study will seek to answer other concerns, including those of shipping interests who wonder how sticking all those straws into the river will affect navigation.