Saturday, October 26, 2019

Rankin-Hinds Flood Control District Website and One Lake Plan

The Rankin-Hinds Flood Control District has an interesting website here:

Lots of maps and data regarding the proposed One-Lake project are available on the website, including this one:

Interestingly, the website notes that One-Lake will not contain a mechanical dam like the Reservoir but instead simply involve moving an existing weir 4 miles south.  According to the website, a weir allows water to overflow the top of the structure at all times.  The Reservoir dam contains mechanical gates that can be operated to adjust outflow from the Reservoir (and the water level in the reservoir) from time to time.

So, if the water level in One-Lake is not something that can be manipulated or adjusted for rain events, how does it provide flood control?  The four Army Corp of Engineer lakes in North Mississippi built specifically for flood control have significant vertical capacity available to impound lots of water.  For example, earlier this year Sardis Lake rose approximately 35+ feet and certainly helped mitigate the tremendous flooding experienced in the Mississippi Delta.  There is probably a good answer to this question, but it's not apparent from the website.

Despite this question and although the One-Lake Project has been subject to some controversy, it is important to note that nothing material has been done to prevent another 1979 or 1983 flood event from occurring.  Further, the success of the central core city is important to the entire metropolitan area, and some other cities similar to Jackson have redeveloped around a water feature.  So, if the One-Lake project will encourage the redevelopment of downtown Jackson and reduce the risk of flooding in the Metro area, the advantages just might outweigh the disadvantages.

1 comment:

RWX said...

The purpose of the lake is control flooding by making it easier for water to flow past Jackson. The '79 flood damage was largely due to restrictions in the waterway -- brush, trees, etc. that impeded the flow. Once they clear the vegetation out, keeping that area under water prevents the re-growth.