Bridge, Phillips, Elam Drainage District News

From the desk of Milton Sandy Jr September 1, 2011 Vol 2011-11This newsletter is directed to friends and supporters of our efforts to get something done about the repetitive flooding in Corinth and Alcorn

County which on May 2, 2010, caused loss of life, public and private property and threatened public health and safety by the massive release of raw sewage into flood waters. If you have news, questions or comments, please fire away.

Code RED Flood Threat Returns for September

The flood threat advisory for September is RED. As we discussed in prior newsletters, based on historic weather information September through November bring a much higher probability for flooding- calling for a SEVERE Flood Threat Advisory in September.

RIP-RAP

No I'm not talking about the latest music here. I've been getting a lot of questions lately about rip rap and drainage so I thought I would try to clear up some confusion. Rip rap is a layer of large stones used to protect soil from erosion in areas of concentrated runoff. Rip rap can also be used on slopes that are unstable because of seepage problems.

Rip rap does not prevent flooding and is normally not necessary to improve drainage. It is a method of stabilizing stream banks and preventing erosion. If erosion is not a problem, rip rap is not a solution to either flooding or drainage problems. Removing flood debris, clearing vegetation blocking the flow of water in the channel, and enlarging and modifying the channel may all improve drainage but its not the rip rap.

Rip rap has its advantages and disadvantages even when used for stabilization and must be properly installed for maximum benefit. Rip rap should usually only be used on banks of a particular slope and should usually have a geotextile fabric installed underneath to prevent sediment from being washed from below the rip rap and carried downstream. Detailed specifications are available from the USACOE, engineering firms and highway departments. Many people object to rip rap for environmental and aesthetic reasons when it is not an absolute necessity.

In Corinth, we are fortunate to live on some high, relatively steep hills. We talk about that in the next story following. Throughout the city, we generally enjoy a pretty high rate of fall or slope in the drainage canals which carry water to the Tuscumbia River Canal by way of Elam, Phillips and

Contact: Milton Sandy Jr 662-286-6087 - Fax 287-4187 - E-mail mlsandy@tsixroads.com

Rip rapped Elam tributary south of Waldron Street

Flood Threat for Sept

Bridge Creek Canals. Once storm water from the city reaches the Tuscumbia and the Hatchie the water slows down and sediment will settle to the bottom and accumulate thereby raising the bottom of the stream and eventually causing more flooding along those waterways and in surrounding bottom lands. The worst thing we can do for our neighbors downstream in other parts of the county is to allow construction and maintenance of our canals which results in heavy erosion and sediment going downstream.

Rip-Rap Advantages Rip-Rap Disadvantages1. Provides immediate erosion control2. May be less expensive than concrete or

other structural solutions3. Makes a noticeable impression after

installation

1. Initial cost is high2. Requires future maintenance to replace

rock displaced by heavy flooding3. Collects trash, makes vegetation

management more difficult in the future4. In most cases requires a permit from

USACOE5. Future access for cleaning and

maintenance may be more difficult

Watersheds

Hopefully, many are becoming familiar with the story I've been telling for over a year now about the three historic drainage canals built in the 1912-1924 time period, which today drain 90% of the city of Corinth - Bridge, Phillips and Elam Canals. Every drop of water which falls on the earth has to either evaporate, sink into the ground or drain somewhere. Every land area which drains into a body of water is referred to as a watershed. Smaller watersheds in turn drain into larger watersheds. Each of these canals has an area which forms a watershed. Phillips and Elam drain into Bridge which drains into the Tuscumbia River Canal and so all three are a part of the Tuscumbia Watershed. The Tuscumbia is part of the Hatchie River Watershed and the Hatchie is, in turn, part of the Mississippi River Watershed. Every smaller part is also part of the larger so Elam is also a part of the Mississippi River Watershed. Watersheds are defined by nature and where the water flows- they have nothing to do with any city, county or state boundaries.

Within the city of Corinth, we have smaller tributaries of these 3 historic main canals which each have a smaller watershed of their own and distinct flooding problems. In the last newsletter I talked about the historic tree district of Corinth and downtown Corinth which all drain, mostly underground and sight unseen, into Town Creek which runs behind Briggs Tobacco on Cass St. and joins Elam Creek behind the old Wal-Mart shopping center, across from Combs Court Apartments.

Another tributary of Elam Creek, unamed but which we have discussed and has major flooding problems, drains from above 7th Street past Corinth Nursery on Polk Street and flows Westward under the KCS Railroad, along the railroad, turning behind Bell Gas and joining Elam at the Norfolk Southern Railroad tracks.

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To determine watersheds, engineers use topographic maps provided by the US Geologic Service which show contours that water is assumed to follow- always in a downhill path from higher elevation to lower. The main reference is to elevation in distance above sea level. In Alcorn County we are close to the highest point in the State of Mississippi- Woodall Mountain near Iuka in Tishomingo County at 807' above sea level. We have several respectable peaks in Alcorn County (as Mississippi peaks go) with the 6th highest in the state at Crum Mountain west of Kossuth at 725' above sea level. Between the peaks in Tishomingo, Tippah, Alcorn and Prentiss counties, we are practically in the Alps of Mississippi. We should adopt yodeling and make it a hillbilly tourist event.

SOUTH CORINTH DRAINAGE (The Fifth Street Project)

This past week I received a telephone call from Mrs. Ida King who lives at the corner of White and Crater St. in South Corinth. Mrs. King was referred to me by a couple of my high school classmates, one of whom I shared a nursery with when we were both born a day apart at the old Community Hospital some years ago. Mrs. King was calling about her flooding and since I knew very little about the flooding in that part of town, I wanted to see what I could find out and document for everyone to share. What I had assumed was that the flooding in South Corinth was just from the water backing up across the old Wal-Mart shopping center moving eastward. What I discovered was another major tributary of Elam Canal with its own watershed and unique flooding problems which I have not discussed before.

Mrs. King has lived in her own home almost 9 years now and has had repeated flooding problems, most severely on May 2, 2010 when water came 3' high to her window ledges. She has also been flooded twice in 2011 - in April and again in July but from the back of the house. She was fortunate that the area was declared a disaster area in 2010 and she received FEMA assistance helping with her home repairs and some of her contents. Like my own experience, she lost papers and photographs that had so much sentimental value that can never be replaced. She lives with the fear of mold that she sees evidence of on houses all around her. Up and down Crater St. you see evidence of past flood damage - the house immediately next door has been torn down and an unkempt and overgrown lot now adjoins her well cared for lawn. On both sides of Crater St. are evidence that

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Mrs. Ida King showing high water mark 5/2/2010 flood

flooding has impacted this area for some time.

The good news that I have to report to Mrs. King is that according to FEMA and the flood insurance map, she is not in a special hazard area for flooding. While I'm sure this will make no sense at all to Mrs. King, I must explain that this is only the case for flood insurance. The Federal Government has adopted a policy of trying to get out of “preventing floods” and relies instead on providing flood insurance as their primary means of giving property owners relief from the damages of flooding.

Shown above is a “Firmette” which insurance agents prepare showing designated flood zones where base elevations have been determined to rate flood insurance premiums. The areas designated with blue dots indicate a flood plain where water in a 100 year flood will reach, the area with blue and stripes indicate a flood way where nothing should be built after a community adopts

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FEMA flood insurance map of South Corinth area where Mrs. King resides

the National Flood Plain regulations. These are referred to as special flood hazard areas and indicate where identified flood hazards exist. You can see on the map the area below Mrs. King where Combs Court and the old South Corinth Elementary are located and note that none of these areas were within special flood hazard areas as well.

So how can this be good news? Well for one thing flood insurance should be available at very reasonable rates in this area. Flood insurance is available to people who rent their homes for contents as well as people who own their homes. According to FEMA's website, preferred flood insurance rates (for Zone X, homes built with a crawlspace, basements excluded) $20,000 home and $8,000 contents should be around $129 per year. For renters, contents only coverage (basements excluded) of $8,000 would be around $49 per year. Based on Mrs. King's experience, I'd say these are a lot better odds than Tunica.

To look at this tributary of Elam Creek Canal (which it turns out Mrs. King lives adjacent to) from an overall viewpoint, we looked up USGS topographical maps (map on left shows streets/ same map on right shows only contours) which show the drainage contours of the land in Corinth. The area surrounding this Elam Tributary runs in a southwest direction from its beginning in the back yard beside the residence at 1016 Fifth Street under the old Illinois Central railroad line (2,473'), under the Norfolk Southern railroad line past Proper St (2,431'), mostly underground past Tate St to Cass St beside the old South Corinth Elementary (Easom High) (3,317'), then beside McDonald’s under Hwy 72 to its junction with Elam (630') - a distance of approximately a mile and a half (8,851' total). There appears to be underground culverts going north past 6 th, 7th Streets and

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USGS topo map of Bishop Canal from 5th Street to Hwy 72/Cass St area

connecting with ditches and culverts draining a large surrounding area in that neighborhood probably including parts of Borroum Circle.

In this area the elevation is around 470' above sea level. Some of the water you see flowing under Cass St. beside McDonald’s started in the North Corinth area around 5 th street around 470' above sea level and has made a long journey through Corinth and still has to exit under Hwy 72 before joining Elam Creek at around 425' above sea level on its way to the Mississippi River. This is a fairly steep drop of around 45' in the mile and a half distance to Elam Creek.

Mayor E.S.Bishop was mayor during the flooding in May of 1991 and made a great effort to try and obtain help fixing flooding problems in the city. Mayor Bishop was instrumental in obtaining help and grant funding from the United States Department of Agriculture Soil and Water Conservation Service (now the NRCS) on an EWP (Emergency Watershed Protection) project to improve this tributary starting around Ross Street and going all the way to 5th Street. For lack of a better name, it was deemed the “Fifth Street Project”. I would like to designate this tributary the E.S.Bishop Canal in memory of Mayor Bishop and in my descriptions herein will refer to it as Bishop Canal. Mayor Bishop also helped secure the NRCS grant around 1995 which built a retaining wall behind the old Wal-Mart shopping center and cleared, rip rapped and enlarged part of Elam Canal from Hwy 72 to its junction with Bridge Creek adjoining the Sewer plant.

Representing the city of Corinth at that time, Scott Engineering Services worked with the SCS on the Fifth Street project around 1993. The project was designed to mitigate but not eliminate flooding in the areas adjoining the canal. Limited hydrological analysis was done which showed the canal was barely adequate for a one year flood- a rainfall event which can be expected to happen at least once each year. The improvements done to the canal were only

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Bishop Canal looking South from 1016 Fifth Street

Bishop Canal looking North on Bunch Street

part of the recommended solution. Culverts under most of the streets along the canal needed to be replaced and enlarged and their replacement was 100% the responsibility of the city. As far as I can tell none of those culverts were upgraded as recommended.

In hindsight, this project seems to have done a fairly good job in helping to mitigate flooding in the upstream areas affected. Some of this drainage canal used rip rap but a large portion was done with a more expensive cellular concrete block which appears to permit easier maintenance and, if mowed, is smoother and allows improved water flow. Some areas used rock encased in metal mesh called “gabion” walls. I drove along the canal this past week and took pictures- its appears to be in relatively good shape everywhere except where it crosses Bunch Street and there it needs clearing or it will probably increase local flooding in this neighborhood.

A gabion wall on the West side north of Foote Street has a couple of trees growing through the mesh which will destroy this wall if they are not cut down before they grow much larger.

Some of the areas are not accessible - where it goes under the old ICG railroad for example so I can't report what the conditions are there. And then there is the area downstream from Ross Street where this project began and the hidden portion of Bishop Canal begins.

From Ross Street south to Hwy 72 Bishop Canal passes beside the old South Corinth Elementary School and the large Combs Court public housing apartment complex. During the 1960's, urban renewal grants to the city of Corinth funded a great deal of improvements in this area including the streets. A segment of the canal from Cass Street to somewhere around Meigg Street was put underground at that time. Later in the mid-1970's another segment of Bishop Canal was put underground from Meigg Street to Ross Street.

The underground segment of Bishop Canal consists of a relatively light gauge, probably aluminum, corrugated “arch” metal pipe originally approximately 10.6' at the base by 7' tall - now nearing 50 years old. The total length of this underground culvert is approximately 2,800' or about a half mile. Approximately a mile of the canal is upstream to this arch pipe. This pipe has to carry all the water flowing downstream plus drain all of the surrounding area within the watershed of this canal. It turns out Mrs. King lives almost exactly in the center of this run of underground pipe.

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Bishop Canal looking North on Foote Street

After the flood of May 2, 2010, the city of Corinth hired a construction firm from Tupelo to inspect this culvert for flood related damage. The firm furnished a report to the city which was used to apply to FEMA for disaster assistance to repair the damage. FEMA's engineers first reported that the whole structure needed to be replaced at an estimated cost of $3.6 million dollars. FEMA rejected this and the second FEMA engineer report stated that it could be repaired for an estimated $800,000. Based on this information, the present city of Corinth administration has engaged Cook Coggins Engineers to prepare specifications for patching this culvert - the cost of which will be provided by FEMA as disaster grant assistance I understand.

Last years inspection in July showed many hidden dangers within this culvert. I have posted the video on the web at:

https://www.box.net/shared/static/1vgxe05nxlqutphltb6c.swf

for anyone who would like to watch a really dull, poorly lit video tour of underground South Corinth.

I captured a few stills below which show some of the damages illustrated in the video. Although the original culvert was a reported 10.6' by 7' tall (which is the equivalent of approximately a 9' round pipe) in many areas the pipe has been reduced to 5' in height. Side

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Bishop Canal underground segment from Ross to Cass St.in red

drains in many cases were totally blocked. In one instance, raw sewage was entering through a side stormwater drain. Much debris including wood, bricks, rock and trash was evident. The top of the arch pipe culvert had been severely damaged in places apparently from the debris floating on top of rushing water and hammering the culvert.

So what does this all mean? It indicates to me there is a rather large drainage problem in the area of South Corinth which will need to be addressed by the city of Corinth to prevent future flooding. I can only draw on my impressions looking at what all this data seems to indicate to me.

First of all, take a look at the underground entrance to Bishop Canal between Ross and Tate Street in the picture below. Imagine the above ground cross-section portion of that canal being full of water to the top of each side bank. Imagine what is going to happen when it hits the arch pipe. There is no way water will compress and fit into that pipe. Part of the water is going to flow over the top and start moving downhill towards Mrs. King and the new Belk Shopping Center.

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Bishop Canal underground between Ross and Cass

Overhead corrugations shredded by flood debris

Bicycles, garbage cart pieces

Side drain pipes totally blocked

Upstream from this pipe entrance you have two major limiting restrictions – the Norfolk Southern and the old Illinois Central RR form levees and their limited size culverts cause these areas to be natural detention areas. It is likely that the entire 5th Street Project which improved the flow of water from upstream, along with deterioration of the arch culvert and its blockage have contributed to the increased flooding in South Corinth since the mid-1990's. It is likely that the cleaning of the canal upstream of the pipe entrance since the May 2, 2010 flood may have increased the water flow in April and July of this year and contributed to Mrs. King's flooding from the rear of her house.

What happens when this arch pipe is full and the entire above ground area of South Corinth which drains by side ditches and culverts into this arch pipe once again stops up and starts moving downhill towards Mrs. King?

Finally, what happens when this underground pipe and all the other water moving downhill overland hits the square culvert running under Hwy 72 and can't get through?

I'm afraid I have to end this article with more questions than I have answers. While the FEMA grant may look like it will improve something, I'm not sure it is going to be much of a fix. We need a lot more expertise and engineering know how to look at the overall hydrological problems here and develop some practical, environmentally sound solutions to ensure the public health and safety of residents of South Corinth. It would seem to me this half mile tunnel needs more access points, perhaps more open sections and more detention areas for water to flow into rather than into people's homes. Drive down Crater Street and you can readily see the damage flooding has already done. Now is the ideal opportunity to try and come up with some new solutions to some old problems. In the meantime, think about Flood Insurance - your odds are better than Tunica, in my opinion..

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Arch pipe entrance between Ross and Tate Street

Hwy 72 culvert nearing junction with Elam