River In Louisiana Research Articles

Estimating erosion in a riverine watershed: Bayou Liberty-Tchefuncta River in Louisiana.

GOAL, SCOPE, BACKGROUND: Sheet erosion from agricultural, forest and urban lands may increase stream sediment loads as well as transport other pollutants that adversely affect water quality, reduce agricultural and forest production, and increase infrastructure maintenance costs. This study uses spatial analysis techniques and a numerical modeling approach to predict areas with the greatest sheet erosion potential given different soils disturbance scenarios. A Geographic Information System (GIS) and the Universal Soil Loss Equation (USLE) were used to estimate sheet erosion from 0.64 ha parcels of land within the watershed. The Soil Survey of St. Tammany Parish, Louisiana was digitized, required soil attributes entered into the GIS database, and slope factors determined for each 80 x 80 meter parcel in the watershed. The GIS/USLE model used series-specific erosion K factors, a rainfall factor of 89, and a GIS database of scenario-driven cropping and erosion control practice factors to estimate potential soil loss due to sheet erosion. A general trend of increased potential sheet erosion occurred for all land use categories (urban, agriculture/grasslands, forests) as soil disturbance increases from cropping, logging and construction activities. Modeling indicated that rapidly growing urban areas have the greatest potential for sheet erosion. Evergreen and mixed forests (production forest) had lower sheet erosion potentials; with deciduous forests (mostly riparian) having the least sheet erosion potential. Erosion estimates from construction activities may be overestimated because of the value chosen for the erosion control practice factor. This study illustrates the ease with which GIS can be integrated with the Universal Soil Loss Equation to identify areas with high sheet erosion potential for large scale management and policy decision making. The GIS/USLE modeling approach used in this study offers a quick and inexpensive tool for estimating sheet erosion within watersheds using publicly available information. This method can quickly identify discrete locations with relatively precise spatial boundaries (approximately 80 meter resolution) that have a high sheet erosion potential as well as areas where management interventions might be appropriate to prevent or ameliorate erosion.

Dancing into the Past: Colonial Legacies in Modern Caddo Indian Ceremony

THE BICENTENNIAL OF THE LOUISIANA PURCHASE is an appropriate moment to consider the different the peoples of the Louisiana Territory have remembered their history. One group of indigenous inhabitants-the Caddo Indians who, at the beginning of the colonial period, occupied homeland extending across present southwest Arkansas, northwest Louisiana, northeast Texas, and southwest Oklahoma-use particular ceremony, the Turkey Dance, to recall the past. To understand Caddo history within the context of their knowledge system, we might begin with story of Caddo origins: original home of the Caddo was on lower Red River in Louisiana. According to their own traditions . . . . they came up from under the ground through the mouth of cave in hill which they call Cha' kani'na, The place of crying, on lake close to the south bank of Red river, just at its junction with the Mississippi. In those days men and animals were all brothers and all lived together under the ground. But at last they discovered the entrance to the cave leading up to the surface of the earth, and so they decided to ascend and come out. First an old man climbed up, carrying in one hand fire and pipe and in the other drum. After him came his wife, with corn and pumpkin seeds. Then followed the rest of the and the animals. All intended to come out, but as soon as the wolf had climbed up he closed the hole, and shut up the rest of the and animals under the ground, where they still remain. Those who had come out sat down and cried long time for their friends below, hence the name of the place. Because the Caddo came out of the ground they call it ina, mother, and go back to it when they die. Because they have had the pipe and the drum and the corn and pumpkins since they have been people, they hold fast to these things and have never thrown them away.1 fact that Caddo Indians today hold to this account of their origins suggests that their concepts of history differ from those held by folk in societies descended from western European traditions. In the latter case, history is often regarded as linear, chronological narrative concerning flesh-and-blood personages, real events, and actual circumstances that help us understand the past and its connection with the present. For Caddos (and for most other American Indians), history likewise provides an account of how present circumstances developed. But the inclusion of their emergence and separation from underground worlds shared with animal kin as part of that history betoken an altogether different perception of reality. Belief in return to the earth following passage through life on the earth also suggests this, reflecting the Caddos' eternal as well as chronological time frames. At the same time, references to links between emblematic goods and Caddo existence as a people suggest second important function of history, identity formation.2 So it is that every society creates history according to its own understandings of the world and of time/space relationships. Different groups use history for distinctive purposes. means by which communities maintain their histories are varied too. Social structures, political and economic arrangements, ceremonial performances, storytelling, and recognition of special places and emblematic objects all may be used to maintain ties with the past. preservation of historical information in written accounts is important in western or European-derived societies, but such sources are less important or are absent altogether among other groups. Many American Indian communities, for example, embed historical knowledge into variety of texts, including those spoken, crafted, and danced.3 This suggests the need for alternatives to universal definitions of history, ones that understand history in terms of multiple systems of socially constructed ways of knowing.4 Caddo Turkey Dance is an excellent example of non-written historical text. …

The conservation of unionid mussels in Louisiana rivers: diversity, assemblage composition and substrate use

Abstract1. To aid in their conservation, unionid mussel assemblages were surveyed in three relatively unstudied rivers in south‐eastern Louisiana.2. Although total species richness varied among rivers, species diversity (as estimated both by Shannon‐Weaver H′ and rank‐abundance curves) was fairly similar.3. Assemblage composition varied among the rivers, with the West Pearl River having the most dissimilar group of species. The endangered inflated heel splitter, Potamilus inflatus, was found only in the lower Amite River.4. The most common species had size distributions skewed towards larger individuals, but small individuals were collected (including the inflated heel splitter), indicating successful recruitment.5. Mussels were more common in silt than in sand or gravel, perhaps because fine sediments are more stable through time in these river systems.6. The greatest threat to these assemblages is gravel mining in the upper reaches of the rivers. At the present time only rivers with endangered species, or that have been declared scenic rivers, have any protection from gravel mining. Copyright © 2001 John Wiley & Sons, Ltd.

Effects of Environmental Hypoxia Associated with the Annual Flood Pulse on the Distribution of Larval Sunfish and Shad in the Atchafalaya River Basin, Louisiana

The Atchafalaya River basin (ARB) is a hardwood floodplain swamp associated with the Atchafalaya River in Louisiana. When the ARB is inundated by the river's annual spring flood pulse, the decomposition of organic matter causes hundreds of hectares to become hypoxic (dissolved oxygen (DO) ≤ 2.0 mg/L). During this time hypoxic conditions are variable, but they often persist from April through June in more than 50% of the lower ARB. Because for most fishes in the ARB reproduction occurs on the floodplain during the flood pulse, hypoxic conditions may severely impact larval fish abundances. We examined the relationships between larval fish abundance and hypoxic conditions in the ARB during 1994 and 1995. Of the 5,389 larval fishes from 14 taxa that were collected, sunfish Lepomis spp. (73.9%) and shad Dorosoma spp. (19.1%) dominated the assemblage during both years. Overall, there was a strong positive relationship between DO level and the presence of larval sunfish and shad. Higher DO levels were most strongly associated with the presence of larval sunfish in 1994 but with the presence of larval shad in 1995. These abundance patterns appear to be related to differences in ARB inundation during the 1994 and 1995 flood pulses. The mean monthly river stage for 1994 was consistent with a 34-year average, but the mean monthly river stage in 1995 was significantly lower in April and higher in June. These differences in timing and duration of the flood pulse appeared to have important consequences for the reproduction of sunfish and shad in the ARB. Both sunfish and shad larvae were collected almost immediately after local conditions (e.g., turbulence and increasing primary production) caused hypoxic areas to become normoxic (DO > 2.0 mg/L). These abundance patterns suggest that larvae were present in adjacent littoral macrophytes that served as DO refugia. Because widespread hypoxia limits the nursery potential of large areas of the inundated floodplain, the reproductive success of many ARB fishes would benefit from a water management plan designed to increase the exchange of water between the main channel and backwater areas.

Development and reworking of a seasonal flood deposit on the inner continental shelf off the Atchafalaya River

Sediment cores and water column measurements of suspended sediment and flow conditions were taken on the continental shelf off the Atchafalaya River in Louisiana to examine the development and reworking of a seabed flood layer with seasonal variations in river discharge and hydrodynamics. Five stations in water depths of 5–23 m were occupied on the Atchafalaya inner shelf on four cruises from October 1997 to March 1999 representing a range of freshwater input and wave energy conditions. Downcore profiles of the short half-life (53 d) cosmogenic radiotracer 7Be showed a three to fivefold increase in seabed inventory and an increase in depth of penetration during the 1998 high Atchafalaya discharge period (April) at two inshore stations (5–7 m water depth). X-radiograph evidence of the absence of biological mixing at these sites suggests that the 7Be data is recording the deposition of a 1–3 cm thick annual flood deposit. The organic carbon contents and stable carbon isotopic compositions of this flood deposit are distinct and reflect the increased terrestrial influence of the riverine sediment flux. 210Pb and 137Cs sediment profiles indicate that this seasonal deposit is two to six times the long-term (e.g., decadal) accumulation at these sites. Passage of cold fronts on 3–7 d timescales interrupts the formation of these flood deposits, particularly during the rising to early high discharge period (December–March). The depth of sediment resuspension landward of 10 m water depth during these events may reach 1 cm and decreases offshore. Offshore stations (∼20 m water depth) show only a small increase in deposition during the high Atchafalaya discharge period. Redistribution of sediment from shallower parts of the shelf during the remainder of the year is likely a major supplier to these areas. A station east of the Atchafalaya mouth exhibits no correlation with discharge and no long-term accumulation, indicating minimal influence from the Mississippi discharge 150 km to the east.

Entropy-Based Assessment of Water Quality Monitoring Networks

Assessment of water quality monitoring networks requires potential methods to delineate the efficiency and cost-effectiveness of current monitoring programs. To this end, the concept of entropy has been considered a promising method in previous studies as it quantitatively measures the information produced by a network. This paper revises the entropy methodology developed in an earlier study and introduces a new approach for the assessment of combined spatial/temporal frequencies of monitoring networks. The results are demonstrated in the case of water quality data observed along the Mississippi River in Louisiana.

The effects of landscape position on plant species density: Evidence of past environmental effects in a coastal wetland

Here we propose that an important cause of variation in species density may be prior environmental conditions that continue to influence current patterns. In this paper we investigated the degree to which species density varies with location within the landscape, independent of contemporaneous environmental conditions. The area studied was a coastal marsh landscape subject to periodic storm events. To evaluate the impact of historical effects, it was assumed that the landscape position of a plot relative to the river’s mouth (“distance from sea”) and to the edge of a stream channel (“distance from shore”) would correlate with the impact of prior storm events, an assumption supported by previous studies. To evaluate the importance of spatial location on species density, data were collected from five sites located at increasing distances from the river’s mouth along the Middle Pearl River in Louisiana. At each site, plots were established systematically along transects perpendicular to the shoreline. For each of the 175 plots, we measured elevation, soil salinity, percent of plot recently disturbed, percent of sunlight captured by the plant canopy (as a measure of plant abundance), and plant species density. Structural equation analysis ascertained the degree to which landscape position variables explained variation in species density that could not be explained by current environmental indicators. Without considering landscape variables, 54% of the variation in species density could be explained by the effects of salinity, flooding, and plant abundance. When landscape variables were included, distance from shore was unimportant but distance from sea explained an additional 12% of the variance in species density (R2 of final model = 66%). Based on these results it appears that at least some of the otherwise unexplained variation in species density can be attributed to landscape position, and presumably previous storm events. We suggest that future studies may gain additional insight into the factors controlling current patterns of species density by examining the effects of position within the landscape.

Organic and Organometallic Compounds in Estuarine Sediments from the Gulf of Mexico (1993-1994)

Sediment samples from 281 estuarine sites in the Gulf of Mexico were collected in 1993–1994 and analyzed for several classes of organic and organometallic compounds as part of the Environmental Monitoring and Assessment Program of the United States Environmental Protection Agency. Polynuclear aromatic hydrocarbons (PAHs) were the contaminant class found most frequently and in the highest concentrations; the sum of 24 congeners (ΣPAHs) ranged from <5 ng g−1 to 15.500 ng g−1 (dry wt basis). A low percentage of samples (3.9%) exceeded 2000 ng g−1 ΣPAHs, and only six samples (2.1%) exceeded 4000 ng g−1, a level above which adverse biological effects may be expected to occur. Less than 4% of sediments exceeded 20 ng g−1 for the sum of 20 polychlorinated biphenyls (ΣPCBs) and only four samples (1.4%) exceeded 20 ng g−1 for the sum of several organochlorine pesticides (ΣOCPs). A sample from Freeport Harbor, Texas, contained 4230 ng g−1 ΣPAHs, 322 ng g−1 ΣPCBs, and 49.6 ng g−1 ΣOCPs. Tributyltin exceeded 100 ng g−1 in only four samples, all of which were from stations in Corpus Christi Bay or Galveston Bay in Texas. The detection of a suite of organophosphate pesticides was very rare and did not exceed 15 ng g−1. Sediments from the tidally influenced section of the Mississippi River in Louisiana contained low to moderate levels of all classes of organic compounds. The most contaminated sites were in urban estuaries (e.g., Corpus Christi, Galveston, and Pensacola (Florida bays), underscoring the need to concentrate future monitoring and assessment efforts at the regional and local level.

Initial Changes in Habitat and Abundance of Cavity-Nesting Birds and the Northern Parula Following Hurricane Andrew

We examined the initial effects of Hurricane Andrew on nest site availability and abundances of seven species of cavity-nesting birds and the Northern Parula (Parula americana) in a large bottomland hardwood forest associated with the Atchafalaya River in Louisiana. As hurricane damage increased, so did the density of understory vegetation and the number of snags, however, the abundance of cavities did not change. None of the abundances of the individual cavity-nesting species were related to hurricane damage or the availability of cavities. Northern Parula abundance was negatively correlated with hurricane damage and density of understory vegetation. The low abundance of this species in forests heavily damaged by the hurricane may be due to loss of canopy foraging habitat or of Spanish moss (Tillandsia usneoides), one of its principal nesting sites.

Comparison of a matrix solid phase dispersion and a classical extraction method for the determination of chlorinated pesticides in fish muscle

A new multiresidue extraction technique was used to determine incurred chlorinated hydrocarbon pesticide residues in various fish species sampled at 2 locations along the Tensas River in Louisiana. Residue levels of total DDT (combined DDT, DDE, and DDD levels) in fish muscle fillets from paired samples ranged from 0.2 to 3.9 ppm on a wet weight basis. These findings were compared to those of another laboratory that used a different protocol to isolate the residues from the fish muscle fillets. This latter protocol typifies the more complicated, time-consuming protocols used by governmental agencies for screening purposes. Results demonstrated that the new extraction technique reduced analysis time, solvent waste, and cost per sample without affecting the quality of residue detection and measurement.

Nutrient Transport in a Riverine-Influenced, Tidal Freshwater Bayou in Louisiana

Transport of ammonium (NH4+), nitrate + nitrite (NO3−), total Kjeldahl nitrogen (TKN), soluble reactive phosphate (SRP), and total suspended solids (TSS) was measured in a freshwater tidal bayou located in a marsh system near the mouth of the Atchafalaya River in Louisiana. Sampling was conducted six times over one year and was timed to assess effects of seasonal variation in river flow and mean sea level of the Gulf of Mexico on material fluxes. Net fluxes of all materials were large and ebb directed in all seasons except fall, when net transport was 2 to 3 orders-of-magnitude smaller than in any other season. These results demonstrate that riverine forcing was the primary influence on materials transport in all seasons except fall when tidal forcing was most important. The range of net fluxes (g s−1) for each nutrient was as follows (a negative sign indicates a net export toward the Gulf): NO3−, −0.006 to −6.69; TKN, 0.09 to −10.41; NH4+, −0.02 to −1.36; SRP, −0.001 to −0.53; TSS, −2 to −81. Analysis of nutrient concentrations indicated the marsh/aquatic system removed NO3−, SRP, and TSS from the water column from late spring through early fall and released NH4+ and TKN in summer. The results of this study show that net materials export per unit cross section channel area increased as riverine influence increased.

Prosperous Blacks in the South, 1790-1880

THERE ARE ALSO, IN THE VICINITY, a large number of free-colored planters, Frederick Law Olmsted wrote in 1856, a few years after a steamboat trip down the Cane River in Louisiana. Having stopped at several plantations to take on cotton, he had learned that, in fifteen miles of well-settled and cultivated country on the

Effects of discharge of municipal waste on water quality of the lower Mississippi River

The effects of discharge of municipal wastes on water quality within the lower Mississippi River below Old River have been reevaluated using published water quality data in the Louisiana reach of the river for the water years 1974-1984. A novel graphical technique has facilitated the evaluation of upriver controls on water quality and the identification of sources and sinks along the lower Mississippi. Comparison of calculated annual fluxes at different down-stream monitoring stations has simplified some of the problems inherent in evaluating analyses of samples collected from different water masses during a typical sampling run. With the exception of an increase in bacterial count, the discharge of municipal waste into the Mississippi River in Louisiana appears to have had no significant effect on water quality, a finding consistent with the earlier US Geological Survey study of Wells (1980). It would be highly desirable for future mass balance studies if existing water quality programs on the Mississippi River were to adopt a Lagrangian sampling approach.

Food quality and foraging response by the subterranean termite Coptotermes formosanus shiraki (isoptera: rhinotermitidae)

AbstractIn previous laboratory studies, it was demonstrated that baldcypress (Taxodium distichum) diets eliminated a critical gut protozoan, Pseudotrichonympha grassii, from Coptotermes formosanus Shiraki. The present authors surveyed field colonies of C. formosanus confined within baldcypress trees growing in a river in Louisiana and found P. grassii was present. Termites inhabiting baldcypress trees preferred pine (Pinus) and rejected baldcypress in choice tests in the field. Significantly more termites were recruited to baits when twice as much pine was offered, indicating that C. formosanus adjusted its foraging response to resource amount. In laboratory tests, sound baldcypress sapwood and heartwood depressed survival and gut protozoan counts in C. formosanus, but baldcypress infected with the basidiomycete fungus Rigidoporus sp. and an unidentified imperfect species was favourable for the termites and their symbionts. These results suggest an important role for microbial modification in termite host selection.

Dating the course of the lower red river in Louisiana: The archaeological evidence

AbstractArchaeological data from the lower Red River in Louisiana indicate that the modern course of the river is 1200 years older than previously suggested. Geologists claim a diversion of Red River through Moncla Gap approximately 500 to 1000 years ago. Marksville period occupations dating prior to A.D. 200 are identified at archaeological sites adjacent to the river below Moncla Gap. The position of these sites on Red River levees demonstrate that they post‐date the river's occupancy of the area. Extensive Marksville and later prehistoric occupations in the Moncla Gap area are seen as a direct result of the development of riverine environments resulting from this diversion.

Chemical characterization of industrial wastewaters by gas chromatography-mass spectrometry

Organic pollutants in seven industrial wastewaters being discharged into the Calcasieu River in Louisiana were identified by gas chromatography-mass spectrometry. Discharge of compounds not indicated from the manufacturer's lists of products and raw materials were revealed. Chemical characterization provided information beyond that obtainable from traditional pollution measurements and information especially suitable for pollution legislation enforcement.

Lateral Erosion and Overbank Deposition on the Mississippi River in Louisiana Caused by 1973 Flooding

In 1973, the Mississippi River was out of its banks for more than 2 mo from April to June. The thickness and the texture of overbank sediments were determined for a number of depositional environments on the Mississippi River flood plain in Louisiana. Average sediment thickness ranged from 53 cm along the natural levee to 1.1 cm in the back-swamp. The texture of deposits varied from natural levee sediments with 68 percent sand to backswamp sediments with 97 percent silt and clay. The amount of lateral erosion of bordering Pleistocene bluffs increased 271 percent over the previous 9 yr of record because of the flood. Using the rate of backswamp deposition during the 1973 flood, it is suggested that backswamp deposits in this area required 10,000 to 11,000 yr to accumulate.

PHYSIOGRAPHIC FEATURES AND STRATIFICATION TYPES OF COARSE‐GRAINED POINTBARS: MODERN AND ANCIENT EXAMPLES1

SUMMARYPrimary sedimentary structures in modern point bar deposits of the Amite River in Louisiana and the Colorado River in Texas are analogous to features observed in Eocene Simsboro and Pleistocene Colorado River deposits of the Texas Gulf Coastal Plain.Short‐duration peak flow, channel pattern, average stream gradient of about 2–3 ft./mile, and bank stabilization by dense vegetation are major parameters controlling the depositional pattern of coarse sand and pebble gravel of the Amite and Colorado rivers. Stratification is directly related to specific depositional features and consists of: large‐scale trough‐fill cross‐stratification in the scour pool; trough‐fill cross‐stratification and foreset cross‐stratification in the lower point bar; parallel laminae, large foreset cross‐stratification, and trough‐fill cross‐stratification in the chute bar; parallel inclined laminae, climbing ripple laminae, and mud drapes in the chute fill; and parallel inclined laminae, mud drape, and foreset cross‐stratification in overbank, flood‐plain deposits.Fundamental differences between point bars of bed‐load streams (low suspended load/bed load ratio) and mixed‐load streams (high suspended load/bed load ratio) are that upper point bar sediments with small trough sets and parallel inclined laminae occur only in fine‐grained (mixed load) fluvial deposits, and large scale foresets of chute bars are common to coarse‐grained (bed load) fluvial deposits but are not found in fine‐grained fluvial deposits. Upward fining sequences, characteristic of fine‐grained fluvial deposits, are uncommon in sediments deposited by bed‐load streams such as the Amite and Colorado rivers.The Simsboro Sandstone consists mainly of scour pool, lower point bar, and chute bar sediments. Chute fill and flood‐plain deposits are preserved only in the highest stratigraphic sequence. Pleistocene Colorado River deposits display the same sequence of stratification types as the Simsboro but are composed of coarser material.