Water Issues in Rice Production

Steven Linscombe  |  1/19/2012 8:21:27 PM

Pumping plant that was part of an early southwest Louisiana rice irrigation system

For Louisiana rice producers to obtain high yields and good quality rice, it is essential that they have adequate high quality water for irrigation. One of the features of southwest Louisiana that first attracted pioneers to attempt rice production in the region was the abundance of surface water available from the bayous and rivers that flow south to the Gulf of Mexico. Later, when deep wells were first drilled, it also became evident that the region had an abundance of high quality groundwater available to allow for rice production where surface water was not readily available. The rapid spread of rice production in southwest Louisiana was facilitated by the establishment of a number of large canal systems in the region. Typically, these systems would be anchored by a large pumping plant on a river or bayou with plenty of available water flow. Most of these pumping plants had huge steam engine-driven pumps that could lift large volumes of water. A large irrigation canal (or system of canals) would then be constructed leading away from the pumping station, often for 20 plus miles. All of the rice fields adjacent to the canals could then be flooded, and in return for receiving the irrigation water, the rice farmer would pay the canal company a percentage of the gross returns from the sale of the rice crop. Most of these major canal systems have disappeared over the past 40 years, and only a few smaller ones remain. The reason for the loss of these canal systems is complex and involves economics, infrastructure and government programs. However, the loss of these systems necessitated the drilling of numerous deep wells to keep many fields in rice production.

Today, it is estimated that about 60 percent of Louisiana’s rice acreage is flooded from deep wells while 40 percent is flooded from surface water. If surface water is available, it is typically the irrigation source of choice because of economics. It takes much less energy to lift water a few feet from a surface water source to a rice field than from the several hundred feet necessary with a deep well. Energy use equals money; thus, the economic advantage of surface water becomes apparent.

Surface water quality and quantity are becoming more of an issue in many areas of rice production in Louisiana in recent years. It might be surprising to some that this is the case with the high volume of average annual rainfall received in the region. However, the operative words here are average annual. The Rice Research Station has been keeping detailed weather information since it was established over 100 years ago. During that period, the station has received just below 60 inches of rainfall for an annual average. However, yearly rainfall has varied from a high of 106 inches in 1940 to a low of 31 inches in 1921. In just the past few years, this number has varied from a high of 73 inches in 2004 to a low of 37 in 1999. This year as of mid-December, we are at 42 inches.

Naturally, under drought conditions in certain areas, water availability can become an issue. Some of our surface water pumps are on smaller drainage systems, and if the lack of rainfall is significant, these pumps will not have enough water to pump. Perhaps more important is the complex relationship between our watersheds and the Gulf of Mexico. In simple terms, our rivers, bayous, streams and drainage ditches are systems that remove excessive rainfall and eventually dump this water in the gulf. This water is fresh and then becomes brackish (increased salinity) as it nears the gulf because of the interaction with the gulf’s seawater. Under normal rainfall conditions, the brackish water remains well south of surface water pumps used in rice production. However, under drought conditions, this high salinity water begins to move north when fresh water moving south is lacking. Rice is a freshwater plant and will not produce well and eventually will die as salinity levels in irrigation water increases.

This is the current situation in many rice production areas of Cameron, Calcasieu, Jeff Davis and Vermilion parishes. In addition to drought, the Leland-Bowman locks on the Gulf Intracoastal Water Way were recently damaged and will not be repaired for several months. This is exacerbating the situation by allowing additional high salinity water to flow north and thus increasing salinity in many rice producing areas. The bottom line is that unless we receive high levels of rainfall this winter and early spring, many of these areas will not be able to produce a rice crop next summer.

While this high salinity water is not a problem every year, it is occurring with increasing frequency. It also affects freshwater marsh holdings, waterfowl hunting, freshwater fishing, alligator egg collection and hunting, as well as the vast beef industry along the coast. Beef producers are beginning to worry about fresh drinking water sources for their herds.

The issue is serious enough that a coalition has recently formed to study long-term solutions to this problem. One idea being explored is the possibility of diverting fresh water into the region, possibly into the Mermentau River basin. When one thinks of all the fresh water being dumped into the gulf from the Mississippi/Atchafalaya river system, this idea becomes attractive. The Tech/Vermilion diversion project already in place shows this can be done successfully.

Any such diversion project has a many obstacles to be overcome, including the finding of funding sources. However, it will never have a chance to become reality unless these discussions begin. This coalition should be commended for these efforts.

Permission granted January 15, 2012 by B. Leonards (LA Farm & Ranch) to republish article on www.lsuagcenter.com
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