Lake Bistineau December 8, 2009 Update


The department is poised to finish the final component of a long-range plan to address giant salvinia on Lake Bistineau once the lake’s water level reaches seven feet below pool stage. To date, fall and winter rain events have kept the water level from dropping much below three feet.

The number and placement of trees in the lake is contributing to the proliferation of this plant. The trees offer cover from freeze damage, slow water velocity which encourages silt depositing and the establishment of nursery areas, prevents plant movement and inhibits spraying. Strategic tree removal in relation to nursery areas and the spillway will be one control method considered when the water is down.

After aerial inspection in November, we observed a significant reduction in plant coverage due to heavy rainfall throughout October. While some plants passed through the control structure, stranding of the plants within the lake was the main contributor for the reduction. This proves that utilizing water level fluctuations to strand plants is a successful control method and why much of our attention has been focused on using this method going forward. The immense watershed provides us with more capacity to fluctuate water levels year round.

I have participated in several productive meetings in recent weeks and more are planned. I anticipate meeting with the Louisiana State Land Office, Louisiana National Guard, Department of Environmental Quality, Bossier Police Jury and state legislators in the near future. Most of the meetings are follow-up meetings to address particular issues.

Mark McElroy
Fisheries Biologist

Lake Bistineau October 20, 2009 Update


Lake levels are still on the rise as a result of heavy rainfall during the last few weeks. Therefore, the drawdown to seven feet below pool stage is behind schedule. The goal of the drawdown is to strand the salvinia plants in the lake, but high water levels have allowed the plants to spread into areas that typically do not have water.

The increased rainfall has however caused the salvinia to move, and many acres once covered with giant salvinia have passed over the spillway or through the water control structure. Most of the plants are piling up behind the water control structure on Loggy Bayou Management Area.

Once the lake is down, department staff will further inspect the area. The information gathered will be used in developing a long-term plan for the lake. Efforts will focus on areas showing little response to the drawdown and potential causes for the lack of response. Many of these areas harbor salvinia and become nurseries for the plant.

Excavation and tree removal may be necessary in order lower water levels in these areas. If so, standard procedure will require us to obtain a U.S. Army Corps of Engineers permit. For those areas on private property, an executed agreement will be required.

Despite delaying the drawdown, the high water event does create a positive in this instance. The effects of the seven foot drawdown will be more significant than if the lake was at its normal stage.

We have yet to determine when the gates will be closed. Many factors will play into this decision. We are interested in doing some modifications to the spillway and lake bottom. Some of this work will require the lake bed to be bone dry. Other considerations include permits, MOUs, advertisement for bids, contracts, partnerships and funding. There is a possibility that the lake will be left down for another year or longer.

Mark McElroy
Fisheries Biologist

Lake Bistineau September 28, 2009 Update


The Department of Transportation and Development opened the gates on the Lake Bistineau water control structure to commence the 2009 drawdown of the lake. The lake level will be reduced by seven feet. However, recent rain events have kept the lake up, extending the amount of time required to reach minus seven feet.

This week, LDWF biologists will conduct an aerial assessment of the lake to determine a base line for giant salvinia coverage. In addition, they will evaluate the watersheds that contribute runoff to the lake to determine the extent of giant salvinia in the upper reaches. Lastly, they will take a look downstream of the dam. Several more aerial assessments are planned as the lake level lowers.

The purpose of the drawdown is to strand giant salvinia in the lake. Many have expressed concern that the water control structure does not create a situation where the plants can exit the lake. In this instance, it is not necessary. Salvinia is a fern, and if unable to access water, will dry out and die. Last year’s drawdown, along with foliar herbicide treatments, reduced giant salvinia coverage from 4,500 acres to about 850 acres.

At this time, there are no plans to close the gates. During the drawdown period, the department will evaluate the use of water fluctuation to facilitate plants to move from areas that will not drain. In order to do so, the gates may be closed; the lake will be allowed to fill to a certain level below pool stage and then opened after the plants move to stranding areas. The long-term plan to control giant salvinia in Lake Bistineau will place heavy emphasis on managing water level fluctuations.

The problems associated with Lake Bistineau extend far beyond the salvinia crisis. Many human activities have and continue to contribute to the degradation of the lake’s ecosystem. Over the past few weeks, we’ve spent a great deal of time developing a better understanding of water quality issues in the lake and watersheds. Our discoveries answer some very important questions as to why giant salvinia grows exponentially in this water body. There are many outdated, poorly maintained sewage treatment facilities throughout the watersheds that are responsible for a constant influx of nutrients. As a result, giant salvinia is being nourished, or fertilized in Lake Bistineau.

Sewage discharge is regulated by the Department of Environmental Quality and Department of Health and Hospitals as well as the parishes. Going forward, this issue must be addressed. This department will make the case with those government entities that have jurisdiction over this matter that non-compliance with state and local ordinances is contributing to lake degradation and ultimately giant salvinia growth. Addressing this situation will require routine monitoring of all sewage discharge, which in some instances will include maintenance or new installation.

Therefore, the rapid growth rate and resulting immense coverage of giant salvinia on Lake Bistineau can be directly linked to sewage discharge present in the water body.
Neglecting to address contributing factors will undoubtedly lead to less than desirable long-term results.

Mark McElroy
Fisheries Biologist

Lake Bistineau September 10, 2009 Update


Our friends at DOTD alerted us last week that they will require an additional week to finish their work behind the spillway.  The structure is their responsibility, so we will wait patiently for this work to be completed and look forward to Wednesday, Sept. 16 to begin the drawdown.

Once the drawdown begins, our team will begin a new phase of investigating the issues that plague Lake Bistineau.  Most of you who use the lake are aware that there are back water areas that don’t dewater with a 7 foot drawdown.  Essentially, these areas are cut off from main channels and serve as nurseries for giant salvinia.  This situation is unacceptable if we are to gain control of the plant.  It will be vital for our team to evaluate these areas to understand what can be done.

The complexity of the terrain and sheer number of these areas will make reconnaissance difficult, especially in the upper reaches of the lake.  While much of this work will be performed by ground crews, some of the work will be coordinated with aerial surveys.  Large areas will receive the highest priority.

There is a still lot to be understood, and the answers seem to come in steps.  Obviously, getting the water down is a giant step.  

Mark McElroy
Fisheries Biologist

Lake Bistineau August 31, 2009 Update


The development of the management plan to control giant salvinia in Lake Bistineau is progressing and some form of plan draft is expected to be completed within the next couple of weeks.  Each week, new information is being gathered and processed by the department’s biological staff in an effort to make sound recommendations that bring about plant control for the long term at reasonable and predictable costs.

This web site is our primary tool in keeping the public informed about giant salvinia and activities planned for its control on Lake Bistineau.  We are aware that the plant is growing unabated due to the fact that all foliar herbicide treatments were curtailed.  It was determined that these treatments were not effective in controlling giant salvinia expansion.  The next slated action is the lake drawdown scheduled for Tuesday, September 8.  It is expected to take five to six weeks to lower the lake seven feet.  Other actions are being considered and will be publicized once there is an approved draft management plan. 

While I understand the frustration many of you are experiencing, I wish to remind you that I have only been working on this issue for approximately five weeks.  I remain optimistic that the plan will provide a level of control that is much better than what you’ve been experiencing over the past several years.  Make no mistake, the disease, if you will, is far worse and much more complicated than most are willing acknowledge.  Lake Bistineau’s problems lie beyond the giant salvinia plague, and therefore the solution is complex and requires a comprehensive approach to obtain desirable results.

Much of my optimism results from the positive discussions I’ve had with many parties who have expressed an interest in playing a meaningful role in controlling giant salvinia in Lake Bistineau.  This includes every member of the legislative delegation who claims Lake Bistineau in their districts, as well as others who have constituents that use the lake.  I’ve also had productive meetings with the Louisiana Office of State Parks, Louisiana National Guard, Louisiana Department of Transportation and Development, Louisiana State Land Office, U.S. Army Corps of Engineers and individual lake bottom and front land owners.  The expertise of all mentioned here, as well as others, will play a significant role in our success.   

Thank you for your patience and understanding as we work through the issues.

Mark McElroy
Fisheries Biologist

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