University of Florida Thesis Or Dissertation Formatting

CHANNEL BED CHANGES IN THE LOWER ATCHAFALAYA RIVER AND WAX LAKE OUTLET, LOUISIANA, 1967-2006

JEREMY REYNOLDS

A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE

UNIVERSITY OF FLORIDA

2019

To my parents, my brothers, and all of my friends who have helped support me.

ACKNOWLEDGMENTS

I would like to thank the members of my committee, Dr. Joann Mossa, Dr. Peter Waylen, and Dr. Liang Mao, for their support and encouragement. I would like to specifically thank Dr.

Joann Mossa for her guidance and advice that kept me well on track during this complex process.

I would like to thank my peers, specifically Mohammad Abdulrahman and Chia-Yu Wu, for their support and advice on how to tackle this study.

TABLE OF CONTENTS

page

ACKNOWLEDGMENTS ...... 4

LIST OF TABLES ...... 6

LIST OF FIGURES ...... 7

ABSTRACT ...... 8

CHAPTER

1 LOWER ATCHAFALAYA CHANNEL BED CHANGE ...... 9

Background ...... 9 Data and Methods ...... 12

2 RESULTS ...... 15

Elevation Models ...... 15 Changes in Bed Elevation ...... 15 Atchafalaya River Elevation Changes ...... 16 Wax Lake Outlet Elevation Changes ...... 16

3 DISCUSSION AND CONCLUSION ...... 17

LIST OF REFERENCES ...... 32

BIOGRAPHICAL SKETCH ...... 34

LIST OF TABLES

Table page

1-1 Sediment contributions to Atchafalaya Bay in the Gulf of Mexico (Roberts et al., 1997) ...... 21

1-2 Data Sources for the Lower Atchafalaya River System...... 21

1-3 Total volume channel bed change for the Lower Atchafalaya River and Wax Lake Outlet combined...... 24

1-4 Total volume channel bed change for the Lower Atchafalaya channel...... 25

1-5 Total volume channel bed change for the Wax Lake Outlet channel...... 25

LIST OF FIGURES

Figure page

1-1 United States Geological Survey streamflow field measurements from April 11, 1973 to May 22, 2019. Measurements begin before the 1973 flood...... 20

1-2 Wax Lake Outlet and Atchafalaya channel bed elevation (m) 1967...... 22

1-3 Wax Lake Outlet and Atchafalaya channel bed elevation (m) 1989...... 23

1-4 Wax Lake Outlet and Atchafalaya channel bed elevation (m) 2006...... 24

1-5 Lower Atchafalaya elevation changes (m) and channel bed volume changes (m3) 1967-1989...... 26

1-6 Lower Atchafalaya elevation changes (m) and channel bed volume changes (m3) 1989-2006...... 27

1-7 Lower Atchafalaya elevation changes (m) and channel bed volume changes (m3) 1967-2006...... 28

1-8 Wax Lake Outlet elevation changes (m) and channel bed volume changes (m3) 1967- 1989...... 29

1-9 Wax Lake Outlet elevation changes (m) and channel bed volume changes (m3) 1989- 2006...... 30

1-10 Wax Lake Outlet elevation changes (m) and channel bed volume changes (m3) 1967- 2006...... 31

Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science

CHANNEL BED CHANGES IN THE LOWER ATCHAFALAYA RIVER AND WAX LAKE OUTLET, LOUISIANA, 1967-2006

Jeremy Reynolds

August 2019

Chair: Joann Mossa Major: Geography

The Lower Atchafalaya River system is experiencing major changes in channel bed sediment elevations such as aggradation and degradation in the past four decades. These changes are in part associated with construction of the Wax Lake Outlet in 1941 which was intended to divert floodwaters from the Lower Atchafalaya, and completion of the Old River

Control Project in 1963 which was built to regulate flow into the Atchafalaya River and keep the

Mississippi River in its course. Cross sectional elevation data were used to interpolate channel bed elevations from 1967-2006, and to identify areas in both the Wax Lake Outlet and Lower

Atchafalaya that experienced changes in channel bed elevation. Due to human intervention both upstream and in the Lower Atchafalaya River system, the Wax Lake Outlet is degrading possibly due to its shorter route while the Atchafalaya channel has been severely aggrading across the entire time period.

CHAPTER 1 LOWER ATCHAFALAYA CHANNEL BED CHANGE

Alluvial rivers can change quickly and are very dynamic systems that require an understanding of the characteristics and causes of underlying processes. Water flow is the most important factor in determination of a river channel’s dimensions whereas the suspended sediment load contributes most to the shape of the river and its channel (Schumm, 1985;

Mueller, 2013).

Almost all of the rivers in the United States have been altered in some way by human interactions (Pringle, 2003). Human interference in the form of locks, dams, levees, and flow regulation systems can lead to large changes in suspended sediment and significant downstream channel bed changes (Hupp et al., 2009). These changes to the river’s natural processes can lead to large scale changes in the river network that quickly become visible and have a negative impact on the ecosystems contained in the drainage and floodplain (Gregory, 2006).

Background

The Atchafalaya River begins at the confluence of the Red and Mississippi rivers just north of Simmesport, LA (Piazza, 2014). The river spans 200 kilometers (146 river miles) and at the southern end is divided into the Lower Atchafalaya River and the Wax Lake Outlet, a river control structure designed for flood management (Mossa, 2016). The Atchafalaya River has acted as a distributary river for the Mississippi River for as long as records have kept for in

Louisiana, predating the mid-1500’s, but also received all of the flow of the Red River (Fisk,

1952). In its role as a distributary river, the Atchafalaya currently carries all of the discharge from the Red River as well as ~30% of the discharge and suspended sediment from the

Mississippi River (Mossa, 2016).

At first, the Atchafalaya River began to increase in prominence due to the construction of

Shreve’s cutoff. Completed in 1831, Shreve’s cutoff reduced the length of a bend in the

Mississippi channel in order to improve navigation into Simmesport (Fisk, 1952; Mossa, 2016).

Following completion of Shreve’s cutoff and settlement in the area, a 32 kilometer log jam formed that blocked the Atchafalaya River (Fisk, 1952). Removal of the log jam began in

1838 and was completed in 1861 at the behest of Henry Shreve who believed this course of action to be the only way to prevent silting in the Red River (Reuss, 1998; Mossa, 2016). Shreve was correct in that the Atchafalaya River took on all of the discharge and sediment from the Red

River. However, flow from the Mississippi River into the Atchafalaya increased steadily as the

Atchafalaya was poised to capture all of the Mississippi’s discharge leading to a major delta switch (Roberts, 1998). This effect was compounded by the Atchafalaya’s shorter distance from the convergence of the two rivers to the Gulf of Mexico as well as its gradient advantage over the

Mississippi (Mossa, 2016). The Old River control project, which includes structures to regulate the amount of flow contributed to the Atchafalaya from the Mississippi River and a lock and dam to allow navigation, was completed in 1963 (Mossa, 2013; Mossa, 2016). In 1973, an unusually strong flood shown in Figure 1-1 damaged the structure which led to construction of an

Auxiliary control structure in 1987 (Roberts, 1998; Mossa, 2016). Further, the Red River had a series of locks and dams installed from 1984-1994 to allow for navigation between Shreveport and Old River and likely reduced the amount of sediment allowed into the Atchafalaya.

The Atchafalaya River itself has a set of primary levees flanked by the Morganza and

West Atchafalaya Floodways upstream which direct floodwaters and end at the same latitude as the Atchafalaya River levees near river mile (RM) 55. These levees form the Atchafalaya Basin

Floodway which was designed in accordance with the Mississippi River and Tributaries Project

to carry 1,500,000 cfs (“Lower Atchafalaya Basin Floodway System,” n.d.). Humans had dredged more than 97.9 million m3 (128 million yd3) from the Lower Atchafalaya by 1941 in order to improve connectivity with channels from 0.64 to 17.7km in length (Reuss, 1998).

Historically, the Lower Atchafalaya included several large lakes (Lindenkohl, 1863; Piazza,

2014). Some basin lakes and along-channel lakes have filled in with lacustrine deltas and other sediment deposits (Tye and Coleman, 1989a, 1989b; Hale et al., 1999; Mossa, 2016).

Morgan City is the largest urban area on the Lower Atchafalaya River that was protected by only a levee and a floodwall leading up to 1941 (Reuss, 1998; Mossa, 2016). In order to provide increased control of floodwaters for Morgan City and to prevent fine-grade sediment buildup in both Grand Lake and Six-Mile Lake, the Wax Lake Outlet was constructed near RM

108 and completed in 1942 with levees bordering the length of the channel (Reuss, 1998;

Roberts, 1998; Shaw et al., 2013; Mossa, 2016). The Wax Lake Outlet was designed to take on

20% of the Atchafalaya’s discharge and accompanying sediment flow (Powell, 1996; Mossa,

2016). By 1987, the outlet carried up to 45% of the flow in the system prompting the construction of a weir by the Corps of Engineers in 1988 (Powell, 1996; Roberts, 1998; Mossa,

2016). The weir was designed to provide 70% of system flow to the Lower Atchafalaya River in an effort to combat aggradation in the channel with the remaining 30% going through the Wax

Lake Outlet. Due to pressure from the citizens of Morgan City regarding higher flood stages during high-flow periods, the weir was removed in 1994 (Powell, 1996; Roberts, 1998; Mossa,

2016). Mossa (2016) used data derived from discharge measurements from decades ago and found that mean bed elevations were approximately -15m in the early part of the record and began rising in the late 1940s through the early 1970s, after which they stabilized near -10m with

the exception of the 1973 flood. Mossa (2016) also found that during this period thalweg elevations were generally rising.

The Lower Atchafalaya ends approximately 24 km (15 mi) south of Morgan City at RM

146 whereas the Wax Lake Outlet empties into the Gulf of Mexico via Atchafalaya Bay near RM

123. Both the Lower Atchafalaya and Wax Lake Outlet channels are influenced by tides and occasional storm surges, and these effects decrease upstream. During the study period of 1967-

2006, delta growth steadily increased due to the increased flow into the Atchafalaya River from the Red River and Mississippi River (Roberts, 1998). Further, deltas have been growing due to the relatively shallow Atchafalaya Bay, and initially emerged after a large river flood in 1973

(Figure 1-1); the subaerial deltas have been growing in elevation and prograding outward over the past several decades (Van Heerden and Roberts, 1980; Van Heerden et al., 1983; Roberts and

Sneider, 2003) which indicates a substantial supply of sediment leaving the basin. Suspended sediment contribution patterns from the Wax Lake Outlet and Lower Atchafalaya River are shown to be strongly influenced by construction/removal of the weir on the Wax Lake Outlet and changing amounts of water flow through each channel shown in Table 1-1 (Roberts et al., 1997).

This paper intends to show the changes in bed elevations of both the Lower Atchafalaya River and Wax Lake Outlet over this period from 1967 to 2006.

Data and Methods

Hydrographic survey maps obtained from the Army Corps of Engineers provided the river boundary and river elevation values in 1967, 1989, and 2006 for river miles 100-135. A total of 115 hydrographic maps and 20,153 elevation points were used (Table 1-2). The maps from 1967 and 1989 came in MrSID format and had to be georeferenced in order to gather data from them. The river boundary and elevation values were digitized by hand and mapped in the

NAD 1983 StatePlane Louisiana South FIPS 1702 Feet projection to provide data suitable for an

analysis. Maps from 2006 were provided in a DGN format which allowed for the selection of the pre-digitized river boundary and elevation points. The river boundary from each map was connected to create a continuous polygon of the river.

River elevation values were provided at regular cross sections of both the Atchafalaya

River and Wax Lake Outlets. In order to investigate changes in the river beds, a continuous elevation surface raster needed to be generated for the river channels. Many interpolation methods exist with ordinary kriging or inverse distance weighted (IDW) interpolation as the most commonly used in environmental sciences (Li and Heap, 2011). IDW is best suited for the interpolation of river channels from evenly-spaced cross sectional elevation data (Merwade et al.,

2006). The Inverse Distance Weighted tool was used in ArcMap to generate a raster elevation surface from each year’s elevation cross sections. Each year’s elevation surface was interpolated using that year’s boundary as a processing mask to produce elevations for the river channel only.

This was necessary due to the river meandering between each new time stamp of data.

In order to look at changes in the river bed from year to year, raster calculator was used to display the differences in elevation between the years. The earlier year’s raster was subtracted from the later year’s raster in order to produce an elevation surface that shows the change in elevation over time. This process was completed for 1967-1989, 1989-2006, and 1967-2006.

To further quantify the change across the three time periods, the cut fill tool was used in

ArcMap in order to produce a raster showing the volumetric change in each raster cell from year to year. Since bed elevations were used for cell values, the change from one time point to the next would reflect the change in sediment volume in the cell across the time period. The tool works by applying Equation 1-1 following formula to each cell in the raster:

V = (cell_area) * ΔZ (1-1)

The cell size used for each set of rasters was 10ft x 10ft which would make the formula 100ft2 times the change in elevation of the raster cell in feet. The resulting figures show areas of net sediment gain, net sediment loss, and areas with no change over the time period.

CHAPTER 2 RESULTS

Elevation Models

The results of the IDW for all three years are shown in Figures 1-1, 1-2, and 1-3. For all three years, the highest points in the river boundary can be found on the outer banks of the rivers and in low-water lakes and marshes along the river. Further, the upper portion of the river, specifically Grand Lake and Six-Mile Lake, show higher elevation values. The lowest elevation values of the system are present in the middle of the Lower Atchafalaya and Wax Lake Outlet channels.

In the 1967 elevation model (Figure 1-2), it is clear that the lowest points of the system can be found in the Atchafalaya River’s channel. The majority of the Wax Late Outlet shows elevations higher than those of the Atchafalaya channel below Six-Mile Lake.

Figure 1-3 shows the elevation model for 1989, right after construction finished on the weir across Grand Lake and Six-Mile Lake. This model clearly shows the lowest elevations in the system in the upper 1/3 of the Wax Lake Outlet channel. The Atchafalaya channel below Six-

Mile Lake shows some lower elevation values in the upper half of it (RM 114-124), but this area also shows signs of aggradation. The elevation model for 2006 (Figure 1-4) tells much the same story as the 1989 model. The only difference is more low elevations on the bottom half of the

Wax Lake Outlet and some lower elevations in the channel above Six-Mile lake.

Changes in Bed Elevation

Changes in bed elevation for the whole system from 1967-1989, 1989-2006, and 1967-

2006 are shown from Figure 1-4 through Figure 1-9. Net loss indicates removal of sediment from the bed and a drop in bed elevation while net gain indicated addition of sediment to the bed and an increase in bed elevation. Table 1-3 shows the volumetric changes of bed sediment in the

system. Since the Wax Lake Outlet and the Lower Atchafalaya River channels experience different processes during the study period, both channels must be examined separately to completely understand the processes at work.

Atchafalaya River Elevation Changes

Figure 1-5 shows change in bed elevation from 1967-1989. During this period, Six-Mile

Lake and above showed a loss of sediment while the river below Six-Mile Lake showed clear addition of sediment to the channel.

Bed elevation changes for 1989-2006 (Figure 1-6) are less clear cut than the previous period. Most of the river channel shows an increase in sediment on the inner bank of all bends in the river while outer banks show a loss in sediment and a decrease in bed elevation. The channel bed changes in this portion of the system across the entire period of 1967-2006 mostly follow this pattern as well (Figure 1-7). While Figure 1-7 shows the same pattern of changes on the inner and outer banks, more of the channel is shown to be gaining sediment rather than losing it.

Atchafalaya channel bed volumetric changes are shown in Table 1-4.

Wax Lake Outlet Elevation Changes

Channel bed changes for 1967-1989 are shown in Figure 1-8. With the exception of the lakes and marsh area in the southernmost part of this channel, the entire outlet and Grand Lake lost sediment. Figure 1-9 shows elevation changes for 1989-2006 which is mostly the same as the previous period but with a few notable exceptions. The upper portion of the Wax Lake Outlet gained sediment in this period along with the banks of Grand Lake. However, the overall elevation change from 1967-2006 (Figure 1-10) paints the same picture as Figure 1-8; most of the system loses sediment during the study period with only a few bank areas and marshlands showing increases in sediment. Total volumetric changes for the Wax Lake Outlet are shown in

Table 1-5.

CHAPTER 3 DISCUSSION AND CONCLUSION

Results show that the Lower Atchafalaya River system is gaining sediment despite the construction of the Old River control structure and the Red River locks and dams. These structures were designed to control the amount of flow allowed into the Atchafalaya River and to reduce the amount of suspended sediment in the system. This conclusion supports that of

Roberts’ 1998 study which suggested an increase in suspended sediment in the Atchafalaya.

Continued contributions in full by the Red River and partly by the Mississippi River have led to the steadily increasing sediment load of the river.

Total volume changes in the system show that despite opposing processes in the Wax

Lake Outlet and the Lower Atchafalaya River channel, the Lower Atchafalaya system as a whole has been steadily gaining sediment.

Figure 1-5 shows that from 1967-1989, the Atchafalaya River channel was losing sediment from RM 100-113 ending at Six-Mile Lake. From RM 113-135 the channel was aggrading due to lower water flow and increased suspended sediment load. Lower flow amounts can be attributed to the Wax Lake Outlet taking on more than double the flow it was intended to handle. Increased water flow in the outlet coupled with levees bordering the entire outlet channel caused scouring along the bed which led to major degradation shown in Figure 1-8. In addition to the outlet’s capture of regular system flow, it also served as an outlet for flood waters in the flood of 1973. This event could only serve to exacerbate existing conditions in the system leading to further degradation of the channel.

The time period from 1989-2006 shows a slightly different picture. The Lower

Atchafalaya channel in Figure 1-6 shows a better balance between areas of sediment loss and areas of sediment gain. Table 1-4 shows while the channel overall gained sediment, there was a

volumetric change of only about 50% the amount of the previous period. Further, sediment gaining was less dominant of a process than the previous period. Likewise, Figure 1-9 shows a very balanced picture of bed elevation changes in the Wax Lake Outlet. Table 1-5 shows slightly less of a volumetric change in this period compared to the last period. While sediment loss was by far the dominant process from 1967-1989, the gain and loss of sediment from 1989-2006 was almost equal.

The changes from 1989-2006 across the whole system can be explained by the construction and removal of the weir. The weir existed from 1988-1994 and its intended purpose was to balance the flow of water in the system by decreasing the amount of flow moving through the Wax Lake Outlet and increasing the amount moving through the Lower Atchafalaya channel.

While the weir only existed for six years, its effect of balancing the water flow in the system is very apparent in the data.

When looking at the changes in the Atchafalaya channel over the entire 39 year period from 1967-2006 (Figure 1-7), it is apparent that the channel has been gaining sediment from RM

113-135. Table 1-4 illustrates this aggradation with the channel gaining roughly 270 million cubic meters of sediment despite the net loss of sediment from RM 100-113. This shows that the lowest portion of the river channel is severely aggrading. Further, the Wax Lake Outlet shows a net loss of sediment from 1967-2006 shown in Figure 1-10. While the outlet showed a slight gain in sediment from 1989-2006, overall the outlet channel bed lost more than 104 million cubic meters of sediment (Table 1-5).

Results have implications to engineering and river management as well as concepts including relaxation and response time in fluvial systems because the changing geometry is largely influenced by changes in streamflow and sediment inputs (Schumm, 2005). The Lower

Atchafalaya River system showed a net gain of roughly 167 million cubic meters of sediment over the 39 year period which is expected from a river experiencing decreased flow rates and increased suspended loads. If the Wax Lake Outlet is allowed to continue taking on more than the intended 20% of the system’s flow, this trend of degradation in the outlet and severe aggradation in the Lower Atchafalaya River will continue. If they continue to run unchecked, these processes could have significant effects on ecosystems dependent on the river.

While this study has shown the presence of major changes in bed elevations in both the

Lower Atchafalaya River and the Wax Lake Outlet, future studies need to be conducted looking into bed geometry like riffles and pools. Further, while some environmental effects are apparent, the full extent of ecological consequences is not covered but remains important to any species endemic to the Atchafalaya River system. Future studies should look at the environmental effects and would do well to include data from more current river surveys in order to see if the trend of aggradation in the Lower Atchafalaya and degradation in the Wax Lake Outlet have continued.

Figure 1-1. United States Geological Survey streamflow field measurements from April 11, 1973 to May 22, 2019. Measurements begin before the 1973 flood.

Table 1-1. Sediment contributions to Atchafalaya Bay in the Gulf of Mexico (Roberts et al., 1997) Year Atchafalaya Bay Total Wax Lake Outlet Lower Atchafalaya River Suspended Sediment (tons) Contribution (%) Contribution (%) 1980 52,964,061.2 38.0 62.0 1981 42,034,394.3 40.9 59.1 1982 85,286,706.2 35.4 64.4 1983 108,648,946 36.3 63.7 1984 79,849,746 43.3 56.7 1985 63,866,264.9 43.2 56.8 1986 48,406,312 43.5 56.5 1987 65,185,778.2 40.0 60.0 1988 57,524,600.9 45.3 54.7 1989 68,082,272.9 37.4 62.6 1990 80,863,382.8 30.4 69.6 1991 50,748,558.5 24.7 75.3 1992 63,136,447.3 30.0 70.0 1993 80,773,536.1 36.1 63.9 1994 54,601,680.7 31.4 68.6

Table 1-2. Data Sources for the Lower Atchafalaya River System. Year Source Format Data Description Number of Number of Survey Maps Elevation Samples 1967 Army Corps of MrSID River boundary and 40 7,146 Engineers river elevation Hydrographic Survey 1989 Army Corps of MrSID River boundary and 38 6,916 Engineers river elevation Hydrographic Survey 2006 Army Corps of DGN River boundary and 37 6,091 Engineers river elevation Hydrographic Survey

Figure 1-2. Wax Lake Outlet and Atchafalaya channel bed elevation (m) 1967.

Figure 1-3. Wax Lake Outlet and Atchafalaya channel bed elevation (m) 1989.

Figure 1-4. Wax Lake Outlet and Atchafalaya channel bed elevation (m) 2006.

Table 1-3. Total volume channel bed change for the Lower Atchafalaya River and Wax Lake Outlet combined. Year Total Gain Loss Difference Dominant % of Volume (Mm3) (Mm3) (Mm3) Process Dominant (Mm3) 1967-1989 750.019 -425.568 324.451 -101.117 Gain 56.74% sediment 1989-2006 433.398 -249.760 183.638 -66.122 Gain 57.63% sediment 1967-2006 908.580 -537.747 370.833 -166.914 Gain 59.19% sediment

Table 1-4. Total volume channel bed change for the Lower Atchafalaya channel. Year Total Gain Loss Difference Dominant % of Volume (Mm3) (Mm3) (Mm3) Process Dominant (Mm3) 1967-1989 584.126 -394.550 189.576 -204.974 Gain 67.55% sediment 1989-2006 305.378 -184.53 120.848 -63.682 Gain 60.43% sediment 1967-2006 715.225 -492.629 222.596 -270.033 Gain 68.88% sediment

Table 1-5. Total volume channel bed change for the Wax Lake Outlet channel. Year Total Gain Loss Difference Dominant % of Volume (Mm3) (Mm3) (Mm3) Process Dominant (Mm3) 1967-1989 163.321 -28.357 134.964 106.607 Loss 82.64% sediment 1989-2006 123.837 -62.538 61.299 -1.239 Gain 50.50% sediment 1967-2006 191.506 -43.623 147.883 104.260 Loss 77.22% sediment

Figure 1-5. Lower Atchafalaya elevation changes (m) and channel bed volume changes (m3) 1967-1989.

Figure 1-6. Lower Atchafalaya elevation changes (m) and channel bed volume changes (m3) 1989-2006.

Figure 1-7. Lower Atchafalaya elevation changes (m) and channel bed volume changes (m3) 1967-2006.

Figure 1-8. Wax Lake Outlet elevation changes (m) and channel bed volume changes (m3) 1967- 1989.

Figure 1-9. Wax Lake Outlet elevation changes (m) and channel bed volume changes (m3) 1989- 2006.

Figure 1-10. Wax Lake Outlet elevation changes (m) and channel bed volume changes (m3) 1967-2006.

LIST OF REFERENCES

Fisk, H.N., 1952. Geological Investigation of the Atchafalaya Basin and the Problem of the Mississippi River Diversion. United States Army Waterways Experiment Station. Mississippi River Commission, Vicksburg, MS (145 pp.).

Gregory, K.J., 2006. The human role in changing river channels, Geomorph. 79 (2-3), 172-191.

Hale, L., Waldon, M.G., Bryan, C.F., Richards, P.A., 1999. Historic patterns of sedimentation in Grand Lake, Louisiana. In: Rozas, L.P., Nyman, J.A., Proffitt, C.E., Rabalais, N.N., Reed, D.J., Turner, R.E. (Eds.), Symposium Recent Research in Coastal Louisiana: Natural System Function and Response to Human Influence. Louisiana Sea Grant College Program, pp. 3-12.

Hupp, C.R., Pierce, A.R., Noe, G.B., 2009. Floodplain geomorphic processes and environmental impacts of human alteration along coastal plain rivers, USA. Wetlands 29 (2), 413-429.

Li, J., Heap, A.D., 2011. A review of comparative studies of spatiral interpolation methods in environmental sciences: Performance and impact factors. Ecol. Inform. 6 (3-4), 228-241.

Lindenkohl, H., 1863. Military Map of Part of Louisiana. Scale 1:390,000. http://www.loc.gov/resource/g4010.cw0232500/.

Merwade, V.M., Maidment, D.R., Goff, J.A., 2006. Anisotropic considerations while interpolating river channel bathymetry, J. Hydrology 331, 731-741.

Mossa, J., 2013. Historical changes of a major juncture: Lower Old River, Louisiana. Phys. Geogr. 34, 315-334.

Mossa, J., 2016. The changing geomorphology of the Atchafalaya River, Louisiana: A historical perspective. Geomorphology 252, 112-127.

Mueller, E.R., Pitlick, J., 2013. Sediment supply and channel morphology in mountain river systems: 1. Relative importance of lithology, topography, and climate. J. Geophys. Res. Earth Surf. 118, 2325-2342.

Piazza, B.P., 2014. The Atchafalaya River basin: History and ecology of an American wetland, River Basin: History and Ecology of an American Wetland. Texas A&M University Press, College Station, TX (320 pp.).

Powell, N., 1996. The Wax Lake Outlet Weir and Channel Response. 6th FISC, Federal Interagency Sedimentation Conference, Las Vegas III. Fluvial: Channel Evolution and Channel Stabilization pp. 46-53.

Pringle, C., 2003. What is hydrologic connectivity and why is it ecologically important? Hydrol. Process. 17, 2685-2689.

Reuss, M., 1998. Designing the Bayous: The Control of Water in the Atchafalaya Basin 1800 1995. Office of History, United States Army Corps of Engineers, Alexandria, VA (474 pp.).

Roberts, H.H., 1998. Delta Switching: Early Responses to the Atchafalaya River Diversion. J. Coast. Res. 14, 882-899.

Roberts, H.H., Sneider, J., 2003. Atchafalaya—Wax-Lake Deltas: new regressive phase of the Mississippi River Delta Complex. Louisiana Geological Survey, Guidebook Series Number 6. A Field Seminar for the Gulf Coast Association of Geological Societies. Baton Rouge, LA (68 pp.).

Roberts, H.H., Walker, N., Cunningham, R., Kemp, G.P., Majersky, S., 1997. Evolution of sedimentary architecture and surface morphology: Atchafalaya and Wax Lake deltas, Louisiana (1973-1994). Gulf Coast Assoc. Geol. Soc. Trans. 47, 477-484.

Schumm, S., 1985. Patterns of Alluvial Rivers. Annu. Rev. Earth Planet. Sci. 13, 5-27.

Schumm, S.A., 2005. River variability and complexity. Cambridge University Press, Cambridge, UK, Cambridge (220 pp.).

Shaw, J.B., Mohrig, D., Whitman, S.K., 2013. The morphology and evolution of channels on the Wax Lake Delta, Louisiana, USA. J. Geophys. Res. Earth Surf. 118 (3), 1562-1584.

Tye, R.S., Coleman, J.M., 1989a. Depositional processes and stratigraphy of fluvially dominated lacustrine deltas, Mississippi River Delta Plain. J. Sediment. Petrol. 59, 973-996.

Tye, R.S., Coleman, J.M., 1989b. Evolution of Atchafalaya lacustrine deltas, south-central Louisiana, Sediment. Geol. 65, 95-112.

U.S. Army Corps of Engineers, New Orleans District, 2008. Lower Atchafalaya Basin Floodway System. https://www.mvn.usace.army.mil/About/Projects/AtchFldySys/.

Van Heerden, I.L., Roberts, H.H., 1980. The Atchafalaya Delta—Louisiana’s new prograding coast. Trans. Gulf Coast Assoc. Geol. Soc. 30, 497-506.

Van Heerden, L.L., Wells, J.T., Roberts, H.H., 1983. River-dominated suspended-sediment deposition in a new Mississippi Delta. Can. J. Fish. Aquat. Sci. 40 (S1), 60-71.

BIOGRAPHICAL SKETCH

Jeremy Reynolds achieved a Bachelor of Arts in geography from the University of

Florida in 2017. After completion of his B.A., he continued his education at the University of

Florida in pursuit of a Master of Science in geography. While working towards his M.S., he has worked for the City of Gainesville doing GIS work for the Department of Mobility. Following his graduation, he plans to enter GIS environmental consulting.