Sewer Aerial Crossing Discharge on January 29, 2016

Remediation and Repairs

Discharge & Emergency Repair

Influent flow reduction noted by operators at approximately 1:45 p.m. on January 29th.

Leak from aerial crossing identified at about 2:15 p.m. and a contractor was called out for an emergency repair. A large branch had fallen and punctured the line.

Contractor arrived and plugged the leak at 3:45 p.m.; a clamp and concrete sealing was installed after leak was stopped.

District contacted TCEQ at 3:20 p.m. and informed of the leak and repair.

After the repair, the area of the leak was disinfected by staff.

As required the “Water Quality Noncompliance Notification” was transmitted to TCEQ on Monday February 1st. The report indicated a spill of approximately 86,000 gallons. The operator calculated the discharge over a 24 hour period and this amount was later amended to 7,200 gallons based on TCEQ instructions for calculating loss time.

The pipe was monitored periodically to ensure its stability.

Public/Media Notification Not RequiredRULE §319.302In addition to the noncompliance notification to the commission required by §305.125(9) of this title (relating to Standard Permit Conditions) and any notification required under Chapter 327 of this title (relating to Spill Prevention and Control), the owner of a facility, through its responsible individual, must notify appropriate local government officials and the local media (see §319.301 of this title (relating to Definitions)) whenever one of the following types of spills occurs from the facility:(1) a spill, regardless of volume, that the facility owner knows or has reason to know, will

adversely affect a public or private source of drinking water;(2) a spill with a volume of 50,000 gallons or more where one or more of the following

conditions also exists:(A) the spill occurs within 1/2-mile of a public or private source of drinking water; N/A(B) the spill occurs within 1/2-mile of a private drinking water well which is located

within 1/2-mile of a public water supply well; N/A(C) the spill occurs within 1/2-mile up-gradient of a surface water intake of a public or

private source of drinking water; N/A(D) the spill occurs in an active groundwater recharge area; N/A(E) the spill occurs up-gradient and within 1/2-mile of a karst terrain or shallow alluvial

well that is a source of drinking water; N/A(3) a spill of 100,000 gallons or more.

Repaired Pipe

Regulatory Site Visits & Requests On February 10th representatives of TCEQ and USACE inspected the site and

TCEQ collected stream samples.

Wastewater Superintendent explained what happened and how the pipe was repaired. USACE requested the District develop a plan for remediation of the site. Plan development was immediately initiated by staff.

On February 12th the General Manager met with USACE at the site. They requested a remediation from a bend upstream of the pipe to a natural dam downstream of the pipe to ensure all solids are removed that may have settled to the bottom of the stream.

Remediation Plan

TAS Environmental was contacted to come on site and remediate the area. They began the process at approximately 6:30 p.m. and expect to be completed on Wednesday February 17th.

The remediation consists of damming the area upstream and downstream and containing the area. Construction of the dams required a path to be cut through two areas of the property to get the machinery in.

Water is contained within this area and the banks are being washed into the contained area.

The water is being pumped to the wastewater treatment plant for treatment.

The area will be groomed by TAS once remediation is completed.

Amended Noncompliance Report On February 12th, the Wastewater

Superintendent discussed the leak with TCEQ Fort Worth office. TCEQinformed him the appropriate way to calculate the leak was from the time the low flow was noticed until the leak was stopped (2 hours). He was informed he should revise the Noncompliance Report to reflect the estimated leak time and volume.

An amended report was transmitted to TCEQ on February 16th reflecting an estimated two hour leak time and volume of 7200 gallons.

Pipe Stability

Shooting the grade on the sewer line indicated a decrease in the slope since the emergency repair was completed.

The sagging in the line can cause the pipe to burst with catastrophic results. The sewer is gravity flow and there would be no way to divert flow immediately should the pipe rupture.

There is no concrete footing supporting the pipe on the west bank side.

Due to bank erosion more pipe is exposed.

The pipe has been determined to be unstable and must be permanently repaired as soon as possible to prevent a catastrophic failure.

Temporary Stabilization of the Pipe Temporary Stabilization by

contractor was started last night and completed this morning.

Two I-beams with chains were used to create a “cradle” for the pipe.

Pipe was raised on west side approximately ½” and it is now level.

Pipe had dripping leak during stabilization. Drip was within the containment area under remediation.

Reported verbally to TCEQ and they stated a written report not required.

Leak was repaired and line is now stable.

USACE agreed we can put fencing around I-beams temporarily.

Other Concerns Bank erosion

continues to threaten the pipe.

Erosion causing trees to become exposed and possibly fall.

Next Steps Preliminary design discussed with engineer and contractor.

Possibly need to add encasement to the pipe to prevent line break from falling trees/debris.

Next Steps (cont.)

Project requires biological survey and archeological survey because it is on federal property. Surveys can be performed this week.

Submit plans to TCEQ through emergency repair approval process. If approved bidding not required.

USACE project approval required. USACE representative said he will give a heads up the project is coming and try to help us obtain expedited approval.

Temporary by-pass will be required while repair is underway.

Estimated cost for permanent repair is $180,000 (includes surveys, engineering, and repair).

Questions?