LOUISIANA DEPARTMENT OF WILDLIFE AND FISHERIES - ANACOCO LAKE OFFICE OF FISHERIES - LOUISIANA DEPARTMENT ...
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LOUISIANA DEPARTMENT OF
WILDLIFE AND FISHERIES
OFFICE OF FISHERIES
INLAND FISHERIES SECTION
2021 AQUATIC VEGETATION CONTROL PLAN
ANACOCO LAKE
Waterbody Information
1. Waterbody type – Impoundment of Anacoco, Caney, Prairie, and Sandy creeks.
2. Age of structure - Anacoco Reservoir was formed in 1951 as a result of Act 277 of the 1948
Louisiana Legislature.
3. Type of Control Structure – Spillway
Spillway location – the spillway is located on the western end of Anacoco dam at the spillway
park.
Spillway crest length – 375’ at 194’ MSL and 125’ at 196’ MSL or a total of 500’
Condition – fair with some weathering/pitting of concrete face
Flow rate – present spillway design for flood – 55,500 CFS (17.36”/5 days)
Control Gate
Gate size – 6’ x 6’ sluice gate
Number of gates – 1
Construction – reinforced concrete control structure
Condition – Poor
Flow rate – draw down 4”/day under ideal conditions
4. Water level - 194.0 MSL at spillway crest.
5. Surface area - 2,600 acres (24,000 acre feet storage); Maximum capacity 82,500 acre feet
6. Average depth – At pool stage the average depth is 9.2 feet; maximum depth is 35 feet
7. Watershed ratio - A total of 209 mi2 of surface area (including the 112 mi2 watershed of Vernon
Lake) drain into Anacoco Lake. The watershed-to-lake ratio is large at 50:1.
8. Drawdown potential of Structure - Under ideal conditions, the reservoir can be drawn down at a
rate of approximately 4” per day with the gate opened to maximum height.
9. Lake Authority - Act 858 of the 1981 Legislature abolished approximately 19 special game and
fish commissions including the Anacoco Prairie Game and Fish Commission. The authority of
the respective game and fish commissions was transferred to the LDWF. State Law provides
authority for parish governments to appoint a panel of citizens to serve in an advisory capacity.
The Vernon Parish Game & Fish Commission fills that role with respect to fish and wildlife issues.
Vernon Parish Game and Fish Commission
Jason Nolde, Chairman
C/o Vernon Parish Police Jury
P.O. Box 1548
Leesville, LA 71446
Authorization – Seven members are selected by the Police Jury to serve at the leisure of the
Police Jury in an advisory capacity only; current civilian members include Arno Arpke, SamFertitta, Jason Nolde (Chairman), Jody Patterson (Secretary), Randy Bennett, and Jury
members David Brister, and Melvin Haymon.
10. What significant stakeholders use the lake?
Anglers, recreational boaters, and waterfowl hunters constitute the majority of the lake users.
No potable water intakes are present on Anacoco Lake.
11. What are their needs and concerns?
Sufficient water levels for their respective activities and a waterbody free of excessive
aquatic weeds.
12. What is the history of aquatic vegetation complaints?
Anacoco Lake historically had high water clarity, and submersed vegetation was a problem.
In more recent years, turbidity has been high and submersed vegetation has not been a
problem. After turbidity levels normalized, LDWF started a native plant restoration effort in
the fall of 2012.
13.Have there been any controversial issues on the lake?
The dam breach of 1956
The original spillway structure failed in 1956, resulting from piping of foundation material
beneath the east section of the stilling basin. Two hurricanes in 1957 hindered construction,
but the new spillway was completed in 1958.
The Construction of Vernon Reservoir Eight Miles Upstream
With the construction of Vernon Lake in 1960 eight miles upstream, the potential fertility of
Anacoco was substantially reduced. When several reservoirs are serially placed on a stream,
the fertility in downstream reservoirs suffers as nutrients are assimilated by aquatic organisms
and sediments in the upstream reservoirs. The Vernon Lake watershed covers approximately
half of the Anacoco watershed. Subsequently, the poor fertility of the watershed soils, the loss
of nutrients due to the Vernon Lake component of the watershed, and the age (64 yrs.) has
resulted in a substantial decrease in fisheries production.
The lakebed renovation of 1999
A lake renovation project was implemented in 1999 and completed in 2000 to stimulate a more
prolonged period of fisheries production.
The turbid waters of 2003 – 2008
Beginning in 2003, water clarity in Anacoco Lake began to decline (The turbid waters of 2010 – 2011
Water quality parameters began to improve in 2009 (Secchi readings >18”). By the spring of
2010, relative abundance of largemouth bass numbers returned to normal (CPUE >50
bass/hour). In October 2010, the drawdown structure was partially opened at the request of
the VPPJ and the Boise Paper Mill to provide downstream flow for mill effluent releases to
keep the mill in operation. The resulting low water conditions within the lake then allowed
settled clay particles to re-suspend into the water column when subjected to wind action.
Average Neophelometric Turbidity Units (NTU) rose from 18.6 in August 2010 to 177.3 in
July 2011.
From January 9 to November 1, 2012, the lake was drawn down to flush out turbid waters
and allow for a renovation including the planting of vegetation to buffer sediments and banks
from wave action. 3,000 Southern bullwhips (Schoenoplectus californicus) were planted
along the shoreline during the drawdown. Fragrant water lily (Nymphaea odorata) and
tapegrass (Vallisneria americana) were planted when the lake returned to pool stage. The
bullwhips and fragrant water lilies thrived, but tapegrass has so far failed to propagate.
Turbidity in the lake has drastically improved since the drawdown and plantings. Average
turbidity at the surface near the dam was 30.98 NTU, with a minimum reading of 21.5 NTU
in November. Currently, visibility generally ranges from 15 - 20” +, a vast improvement
from the 2-3” observed throughout 2011.
Past Control Measures:
Biological Control:
None
Chemical Control:
No chemical treatments were made on Anacoco Lake from 1999 to 2012. A list of foliar
herbicide treatments from 2013 – 2020 is in Table 1.
Table 1. Anacoco Lake herbicide treatment history 2013-2020.
Year Number of Acres Primary Vegetation Treated
Treatments* Treated
Water primrose (Ludwigia spp.), Alligator
2013 4 96
weed (Alternanthera philoxeroides)
2014 2 62 Alligator weed
2015 1 34 Alligator weed
2016 3 120 Alligator weed, Water primrose
Alligator weed, Water primrose, Sedge (Carex
2017 3 84
spp.), Common salvinia (Salvinia minima)
2018 1 35 Alligator weed, Sedge
2019 0 0 N/A
2020 0 0 N/APhysical Control:
A drawdown was conducted from January to November 2012 to address turbidity issues and
to improve fish habitat. In 2016, LDWF worked with the lake commission to establish a
drawdown schedule. Anacoco Lake was put on a 7-year drawdown rotation. The first
scheduled drawdown of this rotation was scheduled to start in September of 2019. This
drawdown was moved to 2020 due to the ongoing Vernon Lake drawdown.
Table 2. Anacoco Lake drawdown history 1956-2021.
Date Purpose Success Fishing Depth Who Operated Fish Kills
Closure Below Structure
Pool
Annual 1956- Unscheduled spillway Good No 14 – LDOTD None
1958 breach and repair 16’
Summer/Fall Control nuisance Poor to fair No 6 – 8’ LDWF None
1961-1971 aquatic vegetation
Aug 1 – Oct Control nuisance Poor to fair No 6 – 8’ LDWF None
30, 1974 aquatic vegetation
Aug 1 – Oct Control nuisance Poor to fair No 6 – 8’ LDWF None
30, 1975 aquatic vegetation
Aug 1, 1980 – Fish population Good No 8-10’ LDWF None
Jan 15, 1981 imbalance
Sep 16 – Dec Fish population Good No 8-10’ LDWF None
6, 1982 imbalance
Sep 15, 1989 – Fish population Good No 8-10’ LDOTD None
Jan 15, 1990 imbalance
Sep 15, 1995 – Fish population Good No 8-10’ LDOTD None
Jan 15, 1996 imbalance/property
owner repairs
Feb 1, 1999 – Lakebed renovation Excellent No 12-16’ LDOTD/LDWF None
April 4, 2000
July 20 – Sep Reduce turbidity due Poor- No 8-10’ LDOTD None
30, 2006 to clay suspension turbidity
was back in
6 months
Aug 1, 2008 – Repair/replace Good-new No 14-18’ LDOTD None
Jan 15, 2009 drawdown mechanism gate
Oct 5 –Nov 10, Requested by Boise Mill stayed No 2’ LDOTD None
2010 Inc. and VPPJ in
operation,
but resulted
in
increased
turbidity
Jan 9 –Nov 1, Lakebed renovation Good to No 18’ LDOTD None
2012 excellent
bottom
drying
August 2020 – Fisheries habitat Poor due to No 8’ LDOTD None
January 2021 improvements Hurricanes reported
Laura and
DeltaJanuary 2021 – Fisheries habitat No 18’ LDOTD
January 2022 improvement and lake
renovation
Aquatic Vegetation Status:
Fall 2020
Alligator weed - 20 acres
Water primrose - 25 acres
Estimated biomass for 2021
With a full year draw down at 18 feet below pool, we expect all aquatic weeds to be minimal
in coverage.
Limitations:
Submersed aquatic weeds are a limiting factor. Past efforts to re-establish beneficial aquatic
plants can be found in the approved waterbody management plan. Current coverage is
detailed on the 2019 Anacoco Management plan in Appendix A.
Recommendations:
Chemical Control:
LDWF will continue to control emergent and floating vegetation with herbicides
in accordance with the approved LDWF Aquatic Herbicide Application Procedures as needed.
Herbicides used to treat aquatic vegetation will be applied at the following rates (Table 3).Table 3. LDWF Standard Operating herbicide procedure.
Plant Species Herbicide Surfactant
Salvinia spp. Alternative 1 Glyphosate (0.75 gal/acre) Turbulence (or approved
Common/Giant Salvinia Diquat (0.25 gal/acre) equivalent, 0.25 gal/acre)
(April 1 to October 31)
Salvinia spp. Alternative 2 Glyphosate (0.75 gal/acre) Turbulence (or approved
Common/Giant Salvinia Flumioxazin (2 oz./acre) equivalent, 0.25 gal/acre)
(April 1 to October 31)
Salvinia spp. Alternative 3 MSM (1 oz./acre) Turbulence (or approved
Common/Giant Salvinia Flumioxazin (1 oz./acre) equivalent, 0.25 gal/acre)
(April 1 to October 31)
Salvinia spp. Alternative 4 Diquat (0.75 gal/acre) Nonionic surfactant (0.25 gal/acre)
Common/Giant Salvinia
(November 1 to March 31)
Salvinia spp. Alternative 5 Flumioxazin (12 oz./acre) Turbulence (or approved
Common/Giant Salvinia equivalent, 0.25 gal/acre)
(November 1 to March 31)
Water Hyacinth 2, 4-D (0.5 gal/acre) Nonionic surfactant (1 pint/acre)
Water Hyacinth in waiver areas Glyphosate (0.75 gal/acre) Nonionic surfactant (0.25 gal/acre)
(March 15 to September 15)
Alligatorweed/Giant Cut Grass Imazapyr (0.5 gal/acre) Turbulence (or approved
(undeveloped areas) equivalent, 0.25 gal/acre)
Alligatorweed/Giant Cut Grass Imazamox (0.5 gal/acre) Turbulence (or approved
(developed areas) equivalent, 0.25 gal/acre)
American Lotus 2, 4-D (0.5 gal/acre) Nonionic surfactant (1 pint/acre)
American Lotus in waiver areas Glyphosate (0.5 gal/acre) Nonionic surfactant (0.25 gal/acre)
(March 15 to September 15)
American Lotus in waiver areas Triclopyr (0.5gal/acre) Turbulence (or approved
with potable water intakes equivalent, 0.25 gal/acre)
(March 15 to September 15)
Duckweed Diquat (1.0 gal/acre) or Nonionic surfactant (0.25 gal/acre)
Flumioxazin (8 oz./acre) or Turbulence (or approved
equivalent, 0.25 gal/acre)
Cuban Bulrush (sedge) 2, 4-D (0.5 gal/acre) Nonionic surfactant (1 pint/acre)
Cuban Bulrush (sedge) in waiver areas Glyphosate (0.75 gal/acre) Nonionic surfactant (0.25 gal/acre)
(March 15 to September 15)
Water Lettuce Diquat (1.0 gal/acre) or Nonionic surfactant (0.25 gal/acre)
Flumioxazin (6 oz./acre) or Turbulence (or approved
equivalent, 0.25 gal/acre)
Physical Control:
Anacoco Lake was put on a 7-year rotation schedule for drawdowns in 2016. The first
scheduled drawdown was scheduled for September of 2019. Due to an ongoing drawdown on
Vernon Lake, which is upstream of Anacoco Lake on the same stream, the determination to
move the Anacoco drawdown to 2020 was made in mid-2019 by the Commission and LDWF.
The 2020 drawdown was initiated in August of 2020, but Hurricanes Laura and Delta caused
widespread rainfall and re-filled the lake after both storms. The decision was made in late 2020,
after a public meeting, to extend the drawdown through the entire year of 2021 to revitalize the
lake. Drawdowns on this lake are intended for fisheries habitat improvement with aquatic weedcontrol as an added benefit. Biological Control: None at this time.
Appendix A
ANACOCO LAKE
September 19, 2018
Anacoco Lake, in Vernon Parish, was surveyed for the presence of aquatic vegetation on
September 18, 2018. On the day of the survey, water clarity was 51 cm as measured by secchi
disk, and turbidity was measured at 12.9 NTU.
Plant densities were designated as “Low,” “Medium,” and “High.” The heaviest
densities of plants were in the northern portions of the lake, and most notably in the northeastern
end, though earlier spray efforts have been effective in the areas that are perennial problems.
The most common species of concern in these areas were alligator weed (Alternanthera
philoxeroides) and primrose (Ludwigia sp.). These two species made up the majority of plants in
more heavily infested areas. Common salvinia (Salvinia minima) was observed scattered in low
densities. Sources of salvinia are in the cypress trees in the northern portions of the lake, but
densities are currently relatively low in those areas.
Some of the 2’-4’ contour of the lake was occupied by light densities of spikerush
(Eleocharis sp.), pondweed (Potamogeton sp.), coontail (Ceratophyllum demersum) and
stonewort (Nitella sp.). In the winter and spring of 2013, LDWF planted bulrush
(Schoenoplectus californicus), white water lily (Nymphaea odorata), and tape grass (Vallisneria
americana) throughout the lake. So far, bulrush survival has been high with expansion from
existing stands, but there has been no dispersal by seed noted. White water lilies have been
observed in the past, mostly in the northern and western portions of the lake, with a few large
stands present, but not seen at all this year. No surviving tape grass has been observed.
Densities of aquatic weeds were even lower than the previous year’s survey, and are the
lowest in many years. There were very few areas of “high” density, and much of the lake was
devoid of problem vegetation. This is most likely due to combined spray efforts and multiple
high-water events of last year, followed by an extremely hard winter. Stands of bulrush were
affected by the freeze, but no significant losses were observed. Water clarity is improved over
last year. Overall, Anacoco Lake has very few aquatic weed issues at the time of the survey.You can also read
