May 8, 2015
From Don Walker, of The Walker Associates. "The Contractor worked last Saturday to strip the topsoil on the west side of the spillway and to divert the Highway ditch water away from the work area.. He hauled any unusable material off-site on Monday and began grading and installing the "french" drain pipe and has completed this pipe installation minus a few feet necessary to tie into the new spillway apron. With installation of the subsurface drain pipe complete, the Contractor began grading the area between the toe of the Dam and the drain pipe for installation of the filter material. During this process, we encountered an area on the extreme west end of the work area that was too unstable to grade. Undercutting was necessary in this area (about 100' x 24') to remove organic material to a depth of about two (2) feet. It was necessary to install a reinforcing geo-grid in this area and to fill with clay gravel in order to provide a somewhat stable area to install the filter sands. The photos below show this area.
"As of the end of the day yesterday (Thursday), the area was ready for the filter sands to be installed. This will be accomplished today. The Contractor is planning on working tomorrow (Saturday) to continue installation of the filter sands and to also begin final grading of the area between the drain pipe and the Highway 98 ditch on the east side of the spillway so that the filter sand can be installed in that area.
"Next week, we anticipate final grading of both sides of the spillway with "capping" of the remaining filter sands with clay gravel and topsoil. If all goes well, the Contractor should begin the apron removal toward the end of next week.
"As you know, we have had to lower the North Lake level to accomplish this work and to lower the water pressure differential between the Lake level and the spillway apron grade to minimize the sand boil situation. Jonathan opened the valve last Saturday (May 2, 2015) in order to lower the level eventually to elevation 316.8 per the direction of the Ge0technical Engineer. We initially intended to accomplish this level in two (2) stages by lowering to the MDEQ level to finish the work on either side of the spillway and then to stop until the apron work was to begin. The Contractor is now about four (4) days ahead of his own schedule. Based on our monitoring of the speed of the drop in the Lake level and with the Contractor's expected apron schedule, we and Jonathan believe it is necessary to continue the Lake level drop until the desired level is met. Once we reach that level, the North Lake valve will be closed and Ski Lake valve will be opened. With the level of water in Stump Lake, we do not anticipate the level in Ski Lake dropping any lower than the initial drop that was set prior to this recent opening of North Lake.
"The work to date has been difficult with with decisions needing to be made and slight adjustments occurring on a daily basis. The Contractor is making efforts to move this project along as quickly as possible. I feel that he has done so, especially with the unstable conditions encountered. Again, we are monitoring the quantities on a daily basis."
April 13, 2015
Don Walker of The Walker Associates, the engineering firm overseeing the repairs of North Lake Dam, met with the contractor (R&J Construction) and MDOT Thursday, April 9, on-site to discuss options for placing a "coffer" dam on the upsteam side of MDOT's box culvert under Highway 98. They appear agreeable to work with the contractor in making this happen. The Contractor provided a sketch to MDOT to obtain this agreement.
The intent here is to place the "coffer" dam so that we can minimize the water level drop in Ski Lake. We have, however, run into an issue of the level of Stump Lake in relation to Ski Lake. As of April 9, both are now at or very near the same level. As such, water is not draining from Ski Lake. We still need to drop Ski Lake another 1 to 1 and 1/2 feet (it has only dropped about 1"-4" so far). This means that the Stump Lake valve has to be re-opened to allow Ski Lake to drop the needed amount. When the required drop is complete, we will still have about 2 feet of water in the box under Highway 98. Thus, the need for MDOT to approve the "coffer" dam. That is what The Walker Associates, R & J, and MDOT have been working on for to prevent a drastic drop in Ski Lake.
The board members were notified of the situation. The Stump Lake valve had to be opened. Once we get the additional 1 to 1 and 1/2 foot drop in Ski Lake, the valve can be closed. We will keep everyone informed when that happens.
March 25, 2015
The pipe liner for the Oak Grove Lake has been completed and the valve on Oak Grove Lake has been closed. The Stump Lake valve will remain open for a few more days and probably will be closed no later than Tuesday or Wednesday of next week to allow the final few days of repairs to the dam to be completed without any problems.
The North Lake valve will be opened today and the level will be taken back down to the mark on the tower. This is necessary to facilitate the repairs to the dam in the coming weeks. The Ski Lake Valve will be opened today and will be lowered approximately two feet. This is also to facilitate the repairs to the North Lake Dam in the coming weeks.
Not all have provided email addresses to the association, so please help spread the word to your neighbors about the coming lake level changes and the information provided here.
March 9, 2015
Oak Grove Lake Dam - The work on the spillway continues. Many of you have noticed that the Stump Lake level has been rising and then falling, etc. The reason for this is that Lake Serene POA has been waiting for the pipe between the Oak Grove Lake and Stump Lake to have the liner placed. If the water level is not kept low enough and there is water in the pipe, the work cannot be done. The original liner could not be accomplished as planned due to an obstruction in the pipe that was undetected on an earlier video. The plan then had to be modified and subcontracted out to another company who specializes in this type of work. We were told by the contractor that this would be accomplished in February and obviously, this has not happened. We were then told that the company that is doing the liner work would be in to video the pipe this week, the week of March 9, and then they would be back in town to do the actual lining of the pipe the week of March 23. Once the liner has been placed, the valve on Oak Grove Lake and Stump Lake can be closed. At a meeting of the board of directors held last Tuesday, March 3, the board voted to begin the process of assessing the penalties associated with going over the 100-day contract. The board feels that while some days can be justified, not all of the days can be, and now ask the contractor to provide written justification for each day over the December 23rd deadline. The penalty is $1000/day for each day over the deadline.
North Lake Dam - The North Lake Dam project has been awarded to R & J Construction. The contract will be formally signed very soon, and hopefully the work can begin soon thereafter. The type of work that has to be conducted on the North Lake Dam is extremely weather sensitive, so the contractor will need a block of good dry weather to get this work accomplished in a timely manner. It is hopeful that the North Lake level will not have to be brought down much lower than it is now in order to facilitate the repairs.
Assessment - As we are getting near to completion of the dam projects, if you have not paid your assessment, you are encouraged to do so as soon as possible.
January 15, 2015
Below are three diagrams from the North Lake Dam Project. These include:
There is also an aerial shot of the wet saturated areas below the dam to give a better perspective of the problem resulting from under seepage from the Lake.
The Walker Associates had a meeting in Jackson with the head of the MDEQ Dam Safety Division and his staff to review our proposed plans. The two-hour meeting went very well. They only offered minor suggestions which TWA will incorporate into the plans. The final plans along with the Application to Perform Work will be in MDEQ's hands the week of January 19. MDEQ indicated they should be able to immediately approve the work and send TWA an authorization to proceed. It is TWA's intent to have a contractor give a cost proposal to LSPOA by February 10, 2015. TWA believes the contractor can meet that schedule. If that occurs and the price is within budget, TWA should be able to present that to the LSPOA Board of Directors at the February board meeting.
While the drawings attached give the scope of work, TWA explains further below:
The intent of this work is to "clean up" the wet areas below the dam and to install a filtered drain system blanket to minimize the movement of soil particles from under the dam (sand boils). We performed borings below the dam to identify the existing soil conditions and a topographic survey to identify ground elevations for use in regrading the site. The "North Lake Dam Project Work Area" drawing attached shows the extent of the area to be re-worked in blue. The aerial shows this same area as being the wet zones on both sides of the spillway. The extent of seepage can be easily seen in the aerial. This drawing also shows where we intend to install the underground drain system in pink or red. These underground drains will collect the subsurface water from the new filter blanket we will install and carry it to the stilling basin below the spillway apron. The "North Lake Dam Typical Proposed Subsurface Drain Systems" drawing attached shows how the drain system and the filter blanket will be constructed. Basically, the drain pipe conduit will be surrounded by fine "concrete" sand to help intercept migrating soil particles with a coarser gravel/stone material immediately encapsulating the pipe conduit to allow water to flow minus any potential soil particles. This fine "concrete" sand blanket will be installed in the full area shown in blue on the drawing to allow water movement from the base of the Dam to the underground drain. We will be filling the area to some extent and will be regrading the Highway 98 road ditch so that our work can properly drain. In addition, we are removing the spillway concrete apron and will install a new filter system below the apron. The blanket will be somewhat thicker but will be constructed in like manner to the other blanket described. A new concrete apron will then be installed with a new concrete rip-rap stilling basin between the new apron and the box culvert under Highway 98. The selected Contractor will also install small weir structures at the end of the subsurface drains to allow measurements of the subsurface flows. A piezometer will be installed in the sand blanket below the spillway with an outlet vertical pipe column to allow measurements of pressure by measuring depth of the water in the vertical column. This will help on future Dam inspections to identify and quantify what is happening below ground.
Oak Grove Lake Dam - Below are photos of work that is progressing along the new embankment as the recommended 3:1 slope develops along the existing dam facing Stump Lake. These photos were taken 11-21-2014. The uniformity of the new slope is largely attributed to the contract requirement for utilization of Automated Machine Grading systems that communicate via GPS technology.
March 20, 2014