详情

原文传递 Low Water Threatens Communities' Fresh Water Supply

题名：	Low Water Threatens Communities' Fresh Water Supply
正文语种：	eng
作者：	FRANK MCCORMACK
摘要：	Just like last year, the Mississippi River is stuck on low, with much of the Mississippi and Ohio valleys experiencing extreme drought conditions. In the last 100 miles of the river, that means salt water moving up river from the Gulf of Mexico is again threatening the fresh water supply of communities along both banks of the river. The riverbed on the lower reaches of the Mississippi River is actually below sea level, which means denser sea water is able to push upstream in low-water conditions. The U.S. Army Corps of Engineers refers to that influx of sea water as a "salt water wedge," and since June the wedge has been pushing upriver through Plaquemines Parish, which extends on both sides of the river for its last 75 miles (above Head of Passes). In July, the New Orleans Engineer District began building a sill at Mile 64 to an initial height of -55 feet. At that height, the sill would deflect the leading edge or "toe" of the salt water wedge, while still allowing deep-draft ship traffic to move on the river. But with the river continuing to drop, both in terms of stage and flow rate, the wedge has continued marching upriver, despite the sill. As of September 21, the toe of the wedge was located somewhere above Mile 66, placing it less than 10 miles below Belle Chasse, the largest city in Plaquemines Parish, and within 20 to 30 miles of St. Bernard Parish and the New Orleans metro area.
出版年：	2023
期刊名称：	The Waterways Jouranl
卷：	137
期：	26
页码：	3,6-7