Below are the USGS water gage outputs for the Mississippi River at Memphis. Last week an all-time recorded low was reported (blue line), even lower than last year’s (brown line). According to Yale Climate Connections:
In Memphis, Tennessee, the river dipped to a new record-low water level of -10.81 feet on Saturday, October 22. The previous record was -10.70 feet, set on July 10 during the notorious summer of 1988. That year had America’s costliest drought since at least 1980, with $51 billion in damages. Data for the Memphis gauge goes back to 1933. (Typically, the zero level on a river gauge is set so that values go negative only during prolonged, intense dry spells.)
Extended drought across much of the great river’s watershed (here and here) has meant reduced agricultural yields in many places. (But as the harvest moves into the second half, I am hearing reports of better yields than expected in some places. A few random showers and better genetics are being credited.) Midstream flows of export crops are being constrained by the reduced stream flows (more and more and more). Further downstream an even more urgent threat has emerged as the reduced flow of fresh water is allowing salt water to move upstream threatening drinking water supplies (more and more).