(KALB) – Even for those unfamiliar with the field of hydrology (the study of the earth’s water and its movement in relation to land), many of the concepts are easily accessible for beginners and commonly found in other areas of everyday life.
To analyze the balance sheet of Louisiana’s fluctuating freshwater stocks, we should start with something many of us may have learned in an introductory economics class: the relationship between supply and demand.
We can break our freshwater sources into three main categories: rain from above, groundwater from below, and surface water from existing basins and reservoirs.
Louisiana receives more rainfall than any other state, getting drenched with an average of 60 inches of rain per year according to a report by the North Carolina Institute for Climate Studies (NCICS).
Utilizing the United States Geological Survey (USGS) and their rainfall calculator, we can estimate how many gallons of water fall each year on the 52,378 square miles within Louisiana’s borders.
The answer: approximately 54.2 billion gallons each year, enough to fill up 82,000 Olympic-size swimming pools!
National Geographic defines an aquifer as a porous body of rock below the earth’s surface that catches water as it seeps through the soil, naturally filtering out pollutants as it goes. The water can naturally bubble back up to the top into a spring or a wetland, or it can be pumped into manmade wells. Thirteen major aquifer systems lie under Louisiana’s soil, many crossing within the boundaries of the ten parishes comprising central Louisiana.
Surface water is everywhere we look in Louisiana. According to the American Geosciences Institute, surface water includes streams, creeks, lakes, rivers, reservoirs and wetlands. There are ten main surface water basins in the state, with six flowing across central Louisiana.
According to an annual report by the Louisiana Department of Transportation and Development (DOTD) in partnership with the United States Geological Survey (USGS), approximately 8.7 billion gallons of water per day were withdrawn from ground and surface water sources in Louisiana in 2015.
This number includes water used by the public for household use, industry operations like manufacturing and power generation, agricultural production, raising livestock, and aquaculture farms harvesting seafood.
The two most water-intensive categories in this list are power generation (withdrawing 4.3 billion gallons per day) and industry (mainly fossil fuel and chemical production, withdrawing 2.2 billion gallons per day).
In 2015, we used about 710 million gallons of publicly supplied water per day, equating to per capita use of 170 gallons per day for Louisiana’s 4.7 million residents (according to the U.S. Census Bureau for 2015).
What does this mean?
There are several important takeaways when you look at Louisiana’s water balance sheet.
1). Simply put, the rate at which we are using our freshwater is far faster than it can naturally replenish itself in the hydrologic cycle.
Louisiana’s hub status for fossil fuel and chemical production, although important for our state’s economic activity, costs us roughly 4.8 billion gallons of water per day.
Calculating these two uses alone, we would need approximately 1.7 trillion gallons of water (4.8 billion x 365 days) to fall each year to balance the current rate of use.
But would more rain really solve the problem?
As highlighted in the Advocate, Louisiana parishes face some of the highest flooding risks in the country. Governor John Bel Edwards and state officials continue to allocate millions toward flood mitigation projects, but these projects take time, and major storms causing hurricanes and flash floods are increasingly unpredictable in their behavior.
2). If we continue exploiting our freshwater supply, we are destined to face harsh consequences long before we hit the bottom of the barrel.
The aforementioned DOT and USGS report found that the greatest proportion of the groundwater withdrawn in the state in 2015 was from the Chicot aquifer system in southwest Louisiana at 48%, followed only by the Mississippi River Alluvial aquifer at 22%.
Years-long research funded by the Louisiana Sea Grant found that each year over 2,300 wells pump water from the Chicot aquifer into farm fields to grow rice, corn, soybeans, and crawfish. Of the 600 million gallons of groundwater pumped into the fields each day, only half of that water returns to the aquifer.
As stated by Tegan Wendland, a seasoned veteran of coastal environmental journalism, we are overdrawing the Chicot aquifer by roughly 350 million gallons a day, a truly unsustainable pattern.
Decades of overdrawing have contributed to a “cone of depression” under the ground, decreasing the water-holding capacity of the aquifer and further risking our future supply.
The Mississippi River Alluvial aquifer, providing freshwater to seven states, is also in bad shape. Due to over pumping from 1987 to 2014, it has suffered a 7-meter drop in the water table according to the federal Forest Service and Department of Agriculture.
Louisiana’s biggest risk in aquifer depletion: saltwater intrusion, sometimes called saltwater encroachment, from the Gulf of Mexico. As over pumping causes the freshwater tables to continue to drop, heavy saltwater pushes into the aquifer and permanently contaminates the supply.
Citing the state’s economic and cultural reliance on the production of commodities in agriculture and aquaculture, we don’t want to wait around and find out what will happen if our farm fields become unsuitable for farming.
3). Possible solutions to this issue may arise from the general public, but the major reforms will have to take place in the energy, industrial, and agricultural sectors.
Public consumption (drinking, bathing, washing clothes, etc.) only accounts for 8% of the state’s use, which means that even if we conserved so much water that we used no water at all, it wouldn’t even make a dent.
This is not a war on industry leaders, farmers, or anyone else. These operations are part of what makes us proud to be from Louisiana. They provide energy, food, jobs, and, most importantly, independence.
The purpose of creating a balance sheet is to look for our blind spots in planning for the future. Let’s start a conversation to share ideas across industries, political parties, and levels of experience. We can learn from each other.
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