Lake Fields is due west of Lockport, south of U.S. Highway 90, and north of the Gulf Intracoastal Waterway in Lafourche Parish and is
approximately 2,000 acres in size. The lake is situated in an inter-levee basin between the Bayou Lafourche natural ridge to the east
and the Bayou Grand Coteau ridge to the west. The Lake is surrounded by primarily "flotant" fresh marsh characterized by shallow ponds,
open marsh grass areas, and extensive wax myrtle thickets. Bottomland hardwoods occur primarily along canal spoil banks. Major water bodies
in the Preserve are identified in FIGURE 1.
The Lake Fields watershed of 52,214 acres originates just south of Thibodaux. The watershed has been significantly altered but is sparsely
populated except for the Bayou Lafourche corridor. The drainage basin is 38.7% agriculture/cropland/grassland, 20% fresh marsh, 18.4% wetland
forests, 9.4% urban, and 8.5% water, with the remainder miscellaneous forests or wetlands.
Prior to the early 1960s, Lake Fields was known for clear water, profuse submergent vegetation, and excellent sport fish and waterfowl populations.
Lake Fields was and remains a very popular recreational site because of the numerous nearby camps and the close proximity to residential areas.
However, sport fish and waterfowl populations have declined dramatically in the lake proper in association with declining water quality and
physical habitat. The lake is currently characterized by low water clarity, high nutrient levels, periodic algal blooms, and a virtual absence
of ecologically important submergent aquatic vegetation.
The ecological deterioration of Lake Fields can largely be attributed to major physical modifications in the watershed. During the 1800s, Lake
Fields was a semi-isolated freshwater lake with a small and undeveloped watershed and surrounded by continuous fresh marsh and drained by Bayou
L’eau Bleu. However, major historical changes in the drainage basin and watershed hydrology eventually significantly increased the inflow of
nutrient-laden, degraded water from the upper watershed into Lake Fields. Major watershed modifications occurred in two phases – nearby private
land reclamation projects in the early 1900s and an upper Bayou Folse watershed drainage project by the U.S. Department of Agriculture Soil
Conservation Service beginning during the late 1960s. As a result of the land reclamation projects, sections of flotant marsh were surrounded
by ring levees, drained with interior canals, and flanked by newly dug exterior canals such as Bayou Folse and Bayou Dumar to facilitate movement
of water downstream. Upper watershed flow initially largely bypassed Lake Fields and drained into Company Canal, but later physical changes
rerouted an increased proportion of flow into Lake Fields. This inflow, which had become increasingly obvious by the 1960s, was associated with
several specific physical watershed modifications. The first was the erosion / subsidence of the west bank of lower Bayou Folse and an oil
exploration canal, which created openings into Lake Fields. The second was the decrease in water depths of Bayou Folse due to the accumulation of
sediments and organic materials. Finally, there were unforeseen, adverse impacts associated with an upper Bayou Folse watershed drainage project
beginning during the late-1960s by the U.S. Department of Agriculture Soil Conservation Service. The project included clearing and deepening of
upper Bayou Folse, pump stations, diverting water from the 40-arpent canal into Bayou Folse, other drainage improvements, and a substantial
increase in watershed drainage area. As a result of these modifications, the flow capacity in upper and mid-Bayou Folse was increased and more
turbid, nutrient-enriched water originating from cattle pasture, farm land, and residential area runoff entered the Bayou. However, lower Bayou
Folse was shallower than upper Bayou Folse and was unable to accommodate this increased flow capacity; subsequently, an increased proportion of
the upper Bayou Folse water flow was diverted through Commercial Canal into Bayou Dumar and eventually into northern Lake Fields. The inflow of
degraded water into Lake Fields via Commercial Canal and Bayou Dumar is illustrated in FIGURE 2. This degraded water then flowed through the
entire lake before exiting through Company Canal at the southeastern corner of Lake Fields.
The increased inflow of nutrient-laden, poor quality water from the upper watershed resulted in immediate and long-term adverse impacts on water
quality and physical habitats in Lake Fields and adjacent marshes. Periodic algal blooms and a dramatic decline in submergent aquatic plants
occurred as water became more turbid and nutrient enriched. Shoreline erosion also accelerated without the wave-dampening cushion provided by dense
growths of submergent and emergent vegetation; eventually the lake rim deteriorated in some areas and exposed the fragile interior wetlands to
wave action and tidal processes.
A comparison of Lake Fields and Lake Long, which is located a few miles south of Lake Fields on the east side of Company Canals and has similar
water depths, provides additional justification for the postulated impacts of degraded water on the Lake Fields ecosystem. In contrast to the
deteriorating physio-chemical and biological environment of Lake Fields, Lake Long is characterized by less turbid water, profuse aquatic vegetation, and excellent
waterfowl and sport fish populations. Lake Long, however, does not receive a significant inflow of degraded water from its drainage basin or
Company Canal.
The Lafourche Parish Game and Fish Commission (Commission) coordinated or sponsored several efforts to address the inflow of degraded water
into Lake Fields. After a request of assistance from the Commission, the Department of Wildlife and Fisheries deployed a
dragline in early 1972 to close several cuts from lower Bayou Folse into Lake Fields. The Commission later sponsored several projects to upgrade
the west shoreline of lower Bayou Folse. A first lift was completed in summer of 1976; however,
additional lifts were needed but not completed because of funding constraints. Additional work on the lower Bayou Folse levee took place in early 1981, when
the western bank of lower Bayou Folse was reconstructed from sediments dredged from Lake Fields. In early 1985, lower Bayou Folse was dredged
and deepened to increase flow capacity using a Lafourche Parish dragline. The dredging of lower Bayou Folse and the restoration of the western
bank of Bayou Folse reduced inflow of degraded water into Lake Fields, improved water quality, and increased submergent vegetation.
These improvements, however, were transitory because of the inadequate increase in channel depths, the gradual decrease in lower Bayou Folse water
depths through accumulation of organic materials and sediments, later
expansion of the opening between Bayou Folse and Lake Fields and between Company Canal and Lake Fields, and the continued diversion of Bayou
Folse flow into Lake Fields via Commercial Canal and Bayou Dumar. Lower Bayou Folse was dredged for the second time in 1992 to
deepen the waterway; however, the positive impacts were minimal because less material was dredged and flow capacity was not significantly increased
when compared to the earlier project.
Project Plans
The Commission is promoting a management plan to restore the Lake Fields ecosystem. The Commission has received input from a number of conservation
organizations and governmental institutions including Ducks Unlimited, Barataria-Terrebonne National Estuary Program (BTNEP), Louisiana Department
of Wildlife and Fisheries, U.S. National Resources Conservation Service, and the North Lafourche Levee District. The BTNEP Management Conference
formally endorsed the management plan at their December, 2008 meeting.
The goals of the Lake Fields restoration plan are to: a) improve water quality; b) reduce wave action and shoreline erosion; c) increase emergent
and submergent vegetation; and, d) increase habitat diversity. The aforementioned goals will be accomplished through two independent but
complimentary projects: a) redirection of water flow; and, b) earthern terraces.
Phase I. Redirection of Water Flow
The overall objective of this project is to redirect upper watershed runoff around rather than into Lake Fields by facilitating
Bayou Dumar and Bayou Folse water flow into lower Bayou Folse and eventually into Company Canal. The reduced
input of nutrient laden, degraded water into Lake Fields will improve water quality and stimulate submergent vegetation.
The following specific actions (see
FIGURE 3) are recommended at this point, although an anticipated watershed hydrological modeling study may result in
minor modifications to this plan:
dredge lower Bayou Folse south of Commercial Canal to sufficiently deepen the channel and flow capacity
restrict openings into Lake Fields from lower Bayou Folse, Bayou Dumar, and Company Canal to reduce inflow of degraded water
into the Lake
restrict channel in lower Bayou Dumar to redirect water flow into Commercial Canal, Bayou Folse, and Company Canal
restrict width of Commercial Canal at its intersection with Bayou Folse to deflect upper Bayou Folse flow from Commercial Canal into
lower Bayou Folse
In contrast to earlier attempts to redirect water flow around Lake Fields, the effects of the proposed project should persist. First, the
channel constrictions in lower Bayou Dumar Commercial Canal at its intersection with Bayou Folse will facilitate water flow around Lake Fields.
Second, the sufficient deepening of lower Bayou Folse will increase the flow capacity such that the upper watershed flow is accommodated.
Finally, the size reduction of the three Lake Fields openings along lower Bayou Folse, Bayou Dumar, and Company Canal will also reduce leakage
of degraded water into the Lake.
Dredged materials from lower Bayou Folse should be placed to minimize sloughing of materials back into the channel and should be used beneficially,
including but not limited to: restricting openings from Bayou Folse or
Company Canal into Lake Fields; closing or restricting openings between Bayou Folse and Little Lake; upgrading the eastern bank of Bayou Folse;
and, creating emergent marsh sites in Little Lake. Vegetative plantings of appropriate wetland plant species are recommended at sites subjected to
high energy wave action. An alternative method of reducing upper drainage basin water flow into Lake Fields may be with the strategic placement of
earthern terraces (see next section) adjacent lake openings.
Phase II. Earthen Terraces
Earthen terraces are a viable marsh restoration tool. Terraces are usually arranged in an alternating pattern at 30-degree angles and placed
in a "V" shape (referred to as a "duck wing terrace") so that regardless of the wind direction, calm water will exist on the downwind side of
the terrace. Terraces are usually about four times wider at the base than at the top, two feet or more above water level, and planted with
native vegetation to reduce erosion. Additionally, marsh creation with earthern terraces is easily quantified and qualifies as a mitigation credit.
Priority areas for terrace placement should include the shoreline protecting camps along lower Bayou Folse, shorelines that are subjected to wave
action and subsequent erosion associated with seasonal prevailing winds (ie., southeast in spring, summer, and fall and north in winter), and to
locations that reduce inflow of water into Lake Fields (see FIGURES 4 and
5). For several reasons, the eastern shoreline of Lake Fields should be a high priority: a) two openings into the lake from
Company Canal and lower Bayou Folse are included; b) the shoreline is very susceptible to wave-induced erosion from seasonal southeasterly winds; and,
c) the west bank of lower Bayou Folse prevents spillover of degraded water into Lake Fields and also protects the many camps. Another high priority
location should be lower Bayou Dumar below Commercial Canal. Other high priority locations are adjacent the mouth of Bayou Dumar and the southern
lake rim of Lake Field. The Bayou Dumar terraces will reduce water flow into the lake. The southern shoreline has been subjected to severe
erosion associated with winter time north winds and the interior marshes have become exposed.
There are several terrace placement options that are applicable to Lake Fields: discontinuous terraces perpendicular or angled to the shoreline;
continuous terraces on submerged spoil banks or shorelines. Shallow littoral areas on the landward side of the terraces will provide optimum
conditions for submergent and emergent vegetation. All terraces should be accompanied by vegetative plantings of appropriate wetland plant species.
Benefits
The following table summarizes potential benefits from the proposed management plan.
BENEFITS
HYDROLOGIC RESTORATION
EARTHERN TERRACES
Reduced input of nutrients
X
Greater water clarity
X
X
Increased aquatic vegetation
X
X
Increased habitat diversity
X
Reduced wave action
X
Reduced shoreline erosion
X
Marsh creation
X
Status
The Commission has a cooperative agreement with the North Lafourche Levee District concerning a proposed Levee District mitigation program
within the Preserve. The Levee District will be required to undergo mitigation for wetland alterations associated with hurricane protection
levees in central and north Lafourche Parish. The Levee District has selected Lake Fields as a potential mitigation site under the mitigation
credits option, where mitigation work will be completed and banked prior to permitted projects that result in wetlands alterations. This
agreement will be mutually beneficial to both the Commission and Levee District because it will facilitate both the restoration plan and hurricane
protection efforts.
The Commission is also committed to securing funds to complete the entire proposed restoration plan. Grant proposals will be submitted as
appropriate funds from governmental agencies or conservation organizations are identified. To facilitate the hydrologic restoration component of
the plan, the Commission has begun preliminary discussions concerning a hydrological model of stream flow around Lake Fields and an engineering
evaluation and assessment for dredging lower Bayou Folse.
A word file, including embedded images, of the restoration plan can be
downloaded.
