Water Wars – Will They Make it to the Mississippi Delta?

 

Irrigation Pipe in the Mississippi Delta

Irrigation Pipe in the Mississippi Delta

(Clarksdale, Mississippi) By LIL JOHN MCKEE

EDITORS NOTE: John McKee is a representative from Coahoma County to the Yazoo Mississippi Delta Joint Water Management District (YMD). This thesis, including problem statement, analysis and conclusions are evident of doctoral level research.

 

Map of Mississippi and the Mississippi Delta

 

 

 

In agricultural circles around the world, the Mississippi Delta is known for its rich soil, ample annual rainfall, and its limitless supply of irrigation groundwater.  So the story goes. While such a claim contains a large degree of truth, the real story about water in the Delta is a bit less rosy and a great deal more complicated.

It is no secret that the world may be facing a global fresh water crisis one day due to an expanding population and heartier appetites for more water-consumptive goods (particularly agricultural ones like meat). It is hardly a coincidence that the English word “rival” comes from a Latin word meaning, “One using the same stream as another.” Though the impending crisis merits much discussion, the writer’s aim here is to shed light on a smaller, but no less important crisis, right here in the Mississippi Delta.

According to The Economist, farming accounts for roughly 70% of human water consumption. In the United States itself, fresh water sources in agricultural breadbaskets like California, Arizona, Texas, Colorado, Kansas, Nebraska, and even Arkansas are becoming threatened by decreasing aquifer levels, increasing populations in developed areas, and a hungrier, wealthier world.    This all points to a coming gold rush in the water-rich Mississippi Delta – right? Not necessarily, but maybe, if we play our cards right.

The Problem in the Delta

For years rural residents in the Delta would get water for their homes and animals by driving a small diameter pipe fifteen to twenty feet into the ground and attaching a hand pump.  This aquifer, called the Mississippi Alluvial Aquifer, extends from the surface to roughly 125’ below the surface. Nearly all of the Delta’s irrigation water comes from this aquifer due to the relative ease and cheap cost of boring a hole in the ground 120’ deep wherever one sees fit.  This “well” water, as it is called here, is laden with dissolved iron, which precipitates out as iron oxide when the water comes into contact with air. For this reason center pivots in this region have a rusty appearance despite being quite shiny underneath, and any thirsty soul who drinks well water often develops a “tummy ache” from all the iron within a few minutes.

The limitless reputation enjoyed by our groundwater is due to the fact that it is an aquifer that recharges relatively rapidly from both sides of the Delta–the Mississippi River on the west, and the rivers and aquifers from the bluff hills on the east. The alluvial aquifer is underlain by several other, deeper aquifers, and the relationship between them all is a complicated one; however in simple terms, the big majority of groundwater being used in the Delta is coming from the alluvial aquifer for agriculture. Most drinking water in the Delta now comes from one of the lower aquifers in order to avoid the iron problem.

Ground Water Flow Analysis

Ground Water Flow Analysis

In 1988 there was a drought in the Delta, which dropped stream flows to the minimum allowed by law, and at that point The Mississippi Department of Environmental Quality (MDEQ) ordered that all water withdrawals from Delta streams for beneficial use must stop. As a result, The Yazoo Mississippi Delta Joint Water Management District (YMD) (www.ymd.org), based in Stoneville, was formed for the purpose of managing water resource concerns in the alluvial aquifer.  YMD was created to provide local, non-regulatory solutions to the Delta’s growing water resource challenges.

Since that time, YMD has tracked static water levels in Delta groundwater wells, and unfortunately the data show a steady decline throughout much of the area, particularly in the central Delta, which is located the farthest between the recharge sources on the east and west. Some areas of the Delta are being sufficiently recharged and are showing little or no decline, but the trend in the “cone of depression” in the central Delta shows that it is deepening and expanding outward. YMD and DEQ are actively working together to find workable solutions to stopping and reversing the decline.

10 year declines of the Mississippi Delta alluvial aquifer

10 year declines of the Mississippi Delta alluvial aquifer

YMD staff has spent much of the last 20 years collecting data and analyzing the problem.  Their best guess as to the magnitude of the overdraft (usage minus recharge – like in a checking account) in the cone of depression, which is the red area in the map above (Figure 3) is approximately 300,000 acre-feet annually.  The area is approximately 1,000,000 acres. An acre-foot of water is the amount of water required to cover one acre to a depth of one foot. Annual rainfall in the Delta is around four acre-feet per acre, or about 4,000,000 acre-feet for the red area above.  These figures are approximate, but they serve to generally quantify the magnitude of the problem. Those numbers lead one to believe that the problem is a fixable one.

Not only does the declining aquifer affect future irrigation withdrawals, but it also affects minimum stream flows in the Delta.  Prior to large-scale irrigation, minimum stream flows in the Delta were higher than they are today because at that time, the aquifer level was sufficiently high as to put water back into the streams when the stream flows were low. Today, many streams at low flow periods, typically in the late summer and fall, practically dry up. This has a negative effect on wildlife and on the management of treated wastewater effluent in communities along the stream.

Sunflower River - flow from aquifer into River

Sunflower River – flow from aquifer into River

Solutions

Conservation on the farm is happening fast. Farmers are being educated about wasteful irrigation practices and are being incentivized through federal conservation funds to adopt practices and build structures, which reduce or recapture the amount of irrigation runoff. New techniques and technology offer much promise for efficient water management or “more crop per drop.”  One such gee-whiz technology is an electronic moisture probe, commonly used in Australia, a water-poor country where water efficiency is leaps and bounds ahead of the Delta. The probe measures soil water content every 10cm down to a meter underground and uploads the readings through a cell phone data hookup to a central server, where the hourly decline can be displayed graphically. Thus the producer can determine when to turn irrigation on or off, based on exactly how much water the plant roots are using.

Why wouldn’t we just use the massive amounts of water flowing in the Mississippi River on the Delta’s western border? This is certainly possible, but impediments would be the cost and timely implementation of such a grand project, the possible introduction of non-indigenous invasive species to interior waterways, the huge environmental and navigational impact of such a project, and the effect such a project would have on future flood control vis-à-vis the Levee Boards.

Another possible solution would be inter-basin transfers of water from one water basin flush with water to another one in need of water. Arkansas has implemented such a project, and Mississippi is now considering one, but again, cost, timeliness, and implementation are big impediments. The big flood control lakes at Arkabulta, Sardis, Enid, and Grenada offer another possibility for augmenting flows. The water levels in these lakes are strictly regulated by law; therefore, such a solution promises to be complicated and costly.

One of the quickest, cheapest, and most effective solutions is the impoundment of surface water in existing low places in the Delta. This can be done either by small-scale on-farm projects or on a multi-farm level. The chief agricultural water problem in the Delta for years has been getting water off low places. Now there may be opportunity to use those places for irrigation water storage. One method being implemented currently is the use of weirs to impound water in old bayous and stream runs. A weir is a low level dam that holds water behind it, but allows floodwaters to overtop it in a way that does not exacerbate flooding.

Surface water capture and use on William's Bayou

Surface water capture and use on William’s Bayou

While it is true that the Delta receives ample rainfall annually for growing crops, unfortunately for agriculture most of it comes during the winter and not when the crops need it. Impounding water would not only capture floodwaters to the benefit of those downstream, but it would also provide a beneficial environmental impact for waterfowl and other aquatic species.  For years farmer have endeavored to drain the Delta; there may be incentives now to “wet it back up.”

Another advantage of surface water is the significantly lower energy cost associated with pumping surface water. While a groundwater well might have to pump water from 80’ deep, a surface water pump might only have to pump against a 20’ head or less. The energy required as a result is significantly less and in many cases there may be sufficient enough savings to justify the cost of a surface water impoundment project. Surface water impoundment in Arkansas is already commonplace where their aquifer problems are worse than ours. Like Australia, it is not uncommon to hear of farms in Arkansas using 10% of the tillable land for water impoundment.

In the grand scheme of the Delta water problem, a 300,000 acre feet overdraft is not a great deal of water to overcome in the cone of depression, but add to that the challenge of added irrigation systems on land not currently being irrigated, and the scale of the problem increases. YMD has estimated that the Delta is approximately 62% irrigated, but new wells come on line each year; therefore YMD is endeavoring to stay ahead of the problem so that future expansion does not greatly increase the overdraft.

A final solution would be a regulatory one that restricts water usage. It is not a solution desired by many, but YMD and DEQ have already taken steps to strengthen water permitting requirements by basing the life of a well permit on whether or not users are adopting water conservation practices. It is further encouragement for users to use every possible conservation effort to save water. For the most part, farmers have been understanding of the problem and have been willingly compliant. There has been enough study done now to know that the problem is real and not the whim of non-agricultural interests.

In conclusion, are water wars truly headed here to the Delta? Not if we manage our current and projected overdrafts smartly. We have potential solutions to our water problems that other areas only dream about. When a thirsty Delta corn crop typically uses 1 acre-foot of irrigation water per year in an area that receives 4 acre-feet of rain, there is great promise. The Delta is inordinately blessed with water, but it is imperative that our leadership manages it correctly in the coming generation. Besides the YMD, a huge player in the conservation effort will continue to be the NRCS (National Resources Conservation Service), an organization that is putting millions of dollars into conservation projects across the Delta. In nearly all the cases, the funds are spent in ways that are not only friendly to the environment, but that also provide enhancements to agricultural productivity – smart money.

(All photos courtesy of YMD)

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Comments

  1. A huge benefit could be had by installing a weir at the confluence of Rolling Fork Creek and the Little Sunflower River as well as on the canal North of Rolling Fork that drains Deer Creek to Steeles Bayou. Viewing Deer Creek at Anguilla shows the beauty and water conservation that can be had by the use of these weirs. Drainage is vital to the Delta and must be maintained, but there is no reason why these same drainage systems can’t be utilized to conserve as well as disperse.

  2. Cal, expressed very well!

  3. Charles Bertram says:

    I am always fascinated by the farming techniques used in other parts of the country. In West Texas we have an extremely arid climate. We live and die by annual rainfall. We also get well water from an aquifer. Unfortunately, we have had many dairies relocate from California. The crops they raise drain the aquifer faster than it can replenish. Farmers here are seeing well production drop by as much as 75%. Scary times for a community which is completely sustained by the agriculture industry.

  4. J.B. ‘Dollar # Cotton Don’t Hurt Either”.

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