Mississippi’s 2018 Water Resources Conference – Flow Issues

The Mississippi Water Resources Conference happened in Jackson on April 3-4 and provided many presentations on an array of ground and surface water issues in the state. Rodney Knight from the U.S. Geological Survey’s (USGS) Lower Mississippi-Gulf Water Science Center in Nashville moderated a great session. Usually at this reliably well-run conference, there are one or two presentations that focus on things in Mississippi that are on-point with my and GRN’s work. Rodney’s presentation was one of those.

He presented about how the USGS and other research organizations are assessing streamflow to support bay and estuary restoration along the Gulf of Mexico.Rodney told us first about a Phase I Gulf-wide project to assess where streamflows have been altered the most and the least, and to identify gaps in flow information. The USGS installs and monitors a vast network of stream gauges that transmit real-time information about river stage, discharge, and water quality. Secondly, USGS and associated researchers will dig in more deeply on a Phase II, Mississippi-based streamflow assessment project. Both phases are funded by the RESTORE Act – the post BP oil disaster penalty settlement money targeted for restoration across the Gulf. RESTORE Act funding is allowing the nation’s best water scientists to work on improving the knowledge about how our rivers nourish coastal waters.

Fresh water flow to the Gulf coast is a big deal. From Texas to Florida, major coastal plain river systems deliver fresh water to Gulf bays and estuaries – fresh water mixes in through wind and tidal action, creating salinity ranges that are suitable for productive and stable marshes and for the variety of fish, shellfish and plankton in these nursery areas. Early life stages of oysters, crabs, fish and shrimp need the moderate salinities and abundant food that estuaries provide. Protected sound waters behind barrier islands are extended estuaries and the marine life there also needs moderate salinities.The Mississippi-based Phase II project will feature either the Pearl River or Pascagoula River as its research subject and will make an important contribution to the knowledge of river and estuary dynamics.

The key questions that the Phase II study seeks to address are:1. How far downstream from alteration points do substantial shifts in streamflow characteristics occur?2. How sensitive are estuary freshwater inputs to upstream streamflow alterations?3. Is there a threshold of freshwater alteration below which no signal is detected in an estuary?

While this information would be great to know about any of Mississippi’s large coastal plain river systems, these questions are timely and on-point for the Pearl River. The Rankin-Hinds Pearl River Flood and Drainage Control District – a Levee Board in Flowood, Ms. – has proposed dredging and damming seven miles of the Pearl to create a lake as its preferred alternative for flood control in Metro Jackson. Rather than improve levees, perform strategic channel work, or employ flood-plain buyouts to solve flooding along the Pearl, this plan to dredge and dam the river is being supported as the desired choice by area businesses and local governments. The economic and real estate development that would follow lake creation is being promoted as a lucrative and preferred pathway for servicing bond debt to finance the project.

Because the Pearl River already has the Ross Barnett Reservoir with its a two mile long dam, many downstream stakeholders on the Pearl are questioning what a second dam and lake will do the river’s flow and its ecology, fisheries and habitats. Because the Pearl’s flow affects the estuaries of the western Mississippi Sound, Lake Borgne and the Rigolets, the three questions above posed by the USGS Phase II project are incredibly relevant right now for the river.Lakes created by dams evaporate water into the atmosphere while they store or manage it and release it to downstream river reaches.

A lake’s surface area is wider and more exposed than the narrower ribbon of a river’s surface so a lake always increases surface evaporation compared to the river from which it was created. Lakes change the heat profile of rivers because they release water from a lake that has absorbed more of the sun’s energy due to the lake’s wider surface, lack of tree shading and more hours of sunlight on the water than the narrower river.Rivers transformed into lakes with developed shorelines also gain new constituencies of lakeshore owners, residents, users and businesses that may desire a say in how the water in “their” lake is managed.None of this bodes well for the downstream areas of a river like the Pearl. And if the lake project proceeds in the next couple of years, the answers to the three questions above from the USGS Phase II research will come too late to do much good.

It would be idiotic for federal and state taxpayer money to dredge and dam the Pearl before the RESTORE Act funding (which also comes from Congress) could provide the research that answers these flow questions, but that’s the world we inhabit – full of contradictions.For now, political persuasion is preceding the needed science. But political persuasion cuts both ways. The lake promoters have had good luck asking Congress and the Mississippi Legislature to accommodate them with funding until recently. This spring in the Mississippi Legislature, House Bill 1631 stalled and died in the Senate. It would have provided $95 million in state bonding and grant money to the Drainage District sponsoring the lake project on the Pearl. After the House passed the bill, the questions about the lake’s impact downstream gave Senators pause, and the bill never left the Senate Finance committee.

Also, on the subject of political persuasion, there are ten resolutions from downstream governments/agencies against the lake project on the Pearl, five each from Mississippi and Louisiana. The Mississippi Commission on Marine Resources opposed the lake project in 2015. Hancock, Lawrence and Marion Counties in Mississippi passed resolutions this year to oppose the lake plan, as did the Town of Monticello. In Louisiana, St. Tammany and Washington Parishes and the Towns of Bogalusa and Pearl River passed similar resolutions and this week the Louisiana Senate passed Sen. Beth Mizell’s Concurrent Resolution 5 (SCR5) against the One Lake project on the Pearl.

It’s encouraging to see some of the best river scientists in the United States coming to Jackson Mississippi to share their research – and heartening to realize that the basic research for needed coastal restoration is being planned. If political and funding questions waited for important flow questions to be answered by research, the Pearl River and the fresh water and coastal resources it affects would be better off. Nevertheless, we will stay vigilant.

Andrew Whitehurst is GRN’s water program director and works on Mississippi water and wetland issues.

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