High River Stage Research Articles

Diagnostic sedimentary structures of the fluvial-tidal transition zone – Evidence from deposits of the Rhine and Meuse

AbstractIn mesotidal settings the transition of a coastal plain estuary to the river is marked by the change of a multiple ebb and flood channel configuration to a single channel system. At high river discharge fluvial processes operate, whereas in periods of low discharge the flow is complicated by a tidal component and a landward intrusion of the salt wedge. These hydraulic and morphological characteristics make the transitional zone different from the ‘pure’ fluvial and estuarine environment. Inspection of published and unpublished data from a number of outcrops of Recent and Tertiary deposits of the Rhine reveals that also in a sedimentary sense a transitional zone can be recognized. In order to separate this zone from the upstream fluvial and downstream estuarine environment a sedimentological definition of the fluvial-tidal zone is proposed being the part of river that lies between the landward limit of observable effects of tidal-induced flow deceleration on fluvial cross-bedding at low river discharge and the most seaward occurrence of a textural or structural fluvial signature related to the high river stage.

Evaluation of Ground‐Water and Surface‐Water Exchanges Using Streamflow Difference Analyses1

Abstract: In the karstic lower Flint River Basin, limestone fracturing, jointing, and subsequent dissolution have resulted in the development of extensive secondary permeability and created a system of major conduits that facilitate the exchange of water between the Upper Floridan aquifer and Flint River. Historical streamflow data from U.S. Geological Survey gaging stations located in Albany and Newton, Georgia, were used to quantify ground‐water and surface‐water exchanges within a 55.3 km section of the Flint River. Using data from 2001, we compared estimates of ground‐water flux using a time adjustment method to a water balance equation and found that these independent approaches yielded similar results. The associated error was relatively large during high streamflow when unsteady conditions prevail, but much lower during droughts. Flow reversals were identified by negative streamflow differences and verified with in situ data from temperature sensors placed inside large spring conduits. Long‐term (13 years) analysis showed negative streamflow differentials (i.e., a losing stream condition) coincided with high river stages and indicated that streamflow intrusion into the aquifer could potentially exceed 150 m3/s. Although frequent negative flow differentials were evident, the Flint River was typically a gaining stream and showed a large net increase in flow between the two gages when examined over the period 1989‐2003. Ground‐water contributions to this stream section averaged 2‐42 m3/s with a mean of 13 m3/s. The highest rate of ground‐water discharge to the Flint River occurred during the spring when regional ground‐water levels peaked following heavy winter and spring rains and corresponding rates of evapotranspiration were low. During periods of extreme drought, ground‐water contributions to the Flint River declined.

Riverbank Filtration: Induced Infiltration and Groundwater Quality

Riverbank filtration relies on the streambed and aquifer matrixes to reduce pathogens under varying conditions of induced infiltration resulting from changes in river stage and flow velocity. The Greater Cincinnati (Ohio) Water Works monitored hydrologic parameters and water quality at its Charles M. Bolton well field during a comprehensive flowpath study. The study determined the frequency of occurrence of high river–stage events from historical data and monitored hydrologic parameters to estimate the potential unit infiltration rate. Giardia, Cryptosporidium, algae, spores, particle counts, and turbidity were also monitored. The project investigated potential pathogen/surrogate breakthrough during several high river–stage and infiltration events. High‐stage events occurred less than 4% of the time. Giardia and Cryptosporidium were not detected in any groundwater samples. Increases in surrogate concentrations were minimal and maintained >3.5‐log reduction. The streambed and aquifer have the ability to buffer water quality effects from major increases in the infiltration rate.

Habitat Use by Middle Mississippi River Pallid Sturgeon

AbstractLittle is known about the habitat preferences and needs of pallid sturgeon Scaphirhynchus albus, which was federally listed as endangered in 1990. To learn more about habitat use and selection by pallid sturgeon, sonic transmitters were surgically implanted in 27 individuals from the middle Mississippi River. Study fish were located 184 times (1–23 times/individual) from November 1995 to December 1999. Of the seven macrohabitats identified, pallid sturgeon were found most often in main‐channel habitats (39% of all relocations) and main‐channel border habitats (26%); the between‐wing‐dam habitats were used less often (14%). Strauss's linear selectivity index (Li) values indicated that study fish exhibited positive selection for the main‐channel border, downstream island tips, between‐wing‐dam, and wing‐dam‐tip habitats; they showed negative selection for main‐channel, downstream of wing dams, and upstream of wing dam habitats. Comparison of Li values for four temperature ranges and three daily mean discharge ranges revealed little change in habitat selection due to temperature or discharge. Habitat use patterns also were similar across seasons and discharge regimes, except during spring months when between‐wing‐dam habitats saw greater use and main‐channel and main‐channel border habitat use declined. These changes may have been a response to high river stages associated with spring flooding, which may create favorable feeding areas in the between‐wing‐dam habitats. Enhancement and restoration of habitat diversity, particularly downstream island tip and between‐wing‐dam habitats, may be necessary for the recovery of pallid sturgeon in the middle Mississippi River.

Water movement in the zone of interaction between groundwater and the Columbia River, Hanford Site, Washington

A two-dimensional model that simulates flow pathlines in a vertical cross section oriented perpendicular to the Columbia River has been developed for a location at the Hanford Site. Hydraulic head data from wells and the adjacent river were used to calculate flow direction and velocity in hourly increments for an entire seasonal cycle. River stage cycles extend through a range of several meters, thus exerting a strong influence on water movement in the zone of interaction. By including a fluctuating river stage at the river boundary (center of channel), the model showed that landward of and beneath the shoreline, flow pathlines within the aquifer are deflected downward. The region immediately beneath the shoreline is strongly influenced by river water that infiltrates during high river stage. On the river side of the shoreline, groundwater discharges upward into the river channel, with pathlines converging in the riverbed relatively close to shore. If the model is run assuming a constant, average river stage, these movement features are not represented, thus demonstrating the need to include transient boundary conditions when a fluctuating river stage influences the zone of interaction between groundwater and surface water. The model provides information that supports a variety of applications, including monitoring strategies. contaminant transport models, risk assessments, remedial action design, and compliance requirements for remedial actions.

RECHARGE TO ALLUVIAL VALLEY AQUIFERS FROM OVERBANK FLOW AND EXCESS INFILTRATION1

ABSTRACT: Recharge is an important parameter for models that simulate water and contaminant transport in unconfined aquifers. Unfortunately, measurements of actual recharge are not usually available causing recharge to be estimated or possibly added to the calibration procedure. In this study, differences between observed water‐table elevations and water‐table elevations simulated with a model based on the one‐dimensional Boussinesq equation were used to identify both the timing and quantity of recharge to an alluvial valley aquifer. Observed water table elevations and river stage data were recorded during a five‐year period from 1991 to 1995 at the Ohio Management Systems Evaluation Area located in south‐central Ohio. Direct recharge attributed to overbank flow during and shortly after flood conditions accounted for 65 percent of the total recharge computed during the five‐year study period. Recharge of excess infiltration to the aquifer was intermittent and occurred soon after large rainfall events and high river stage. Specification of constant recharge with time values in ground‐water simulation models seems inappropriate for stream‐aquifer systems given the strong influence of the river on water table elevations in these systems.

Influence of Taxonomy, Ecology, and Seasonality in River Stage on Fish Contamination Risks in Floodplain Swamps of the Lower Mississippi River

We compared contamination levels in fish from contaminated and uncontaminated floodplain swamps of the lower Mississippi River to assess differences in contamination risks between swamps, across different taxonomic and ecological groupings of fishes within and between swamps, and with seasonality in river stage. Fish tissue levels of inorganic contaminants were substantially lower than environmental levels in both swamps, suggesting either that fish were not uptaking these contaminants, or they were effectively eliminating the contaminants from their bodies. Tissue levels of organic contaminants were high relative to environmental levels, suggesting that these contaminants were bioaccumulating. Organic contaminants were significantly higher in fish from the contaminated swamp (Devil's Swamp) than in fish from a reference swamp up river (Tunica Swamp). Because the organic contaminants were largely confined to sediments, we expected bottom-oriented fishes to have higher concentrations than pelagic fishes. Assuming that uptake was primarily through the food chain, we expected top predators to exhibit higher concentrations than low-level consumers. We also expected year- round swamp residents to exhibit higher accumulations than more transitory users of backswamp habitat. However, organic contaminant levels did not differ in the directions expected for any of these groupings. We did observe differences in organic contaminant levels within and between swamps for different taxonomic groupings of fishes (species and genera). Some taxa occupying low to middle positions in the food web (e.g., gizzard shad, Lepomis spp.) exhibited higher concentrations than taxa near the top of the food web. Within Devil's Swamp, organic contaminant levels were significantly higher at low river stage, when fish were confined to the swamp, than at high river stage, when fish were free to move between the river and the swamp. We caught more species and more fish per unit effort in Devil's Swamp than in Tunica Swamp, contrary to expectations if contaminants in the former were negatively impacting population and community structure. Species richness differences between swamps were a consequence of catch differences, with higher catch corresponding to inclusion of more rare species. The lower catch in Tunica Swamp may have resulted from physical modifications of its waterways to support agriculture and hunting. The results of this study underscore the importance in factoring information on the taxonomy and ecology of organisms, and seasonal changes in environmental conditions, into assessments of contamination risks.

INTERACTIONS BETWEEN GROUND WATER AND SURFACE WATER IN THE SUWANNEE RIVER BASIN, FLORIDA1

ABSTRACT: Ground water and surface water constitute a single dynamic system in most parts of the Suwannee River basin due to the presence of karst features that facilitate the interaction between the surface and subsurface. Low radon‐222 concentrations (below background levels) and enriched amounts of oxygen‐18 and deuterium in ground water indicate mixing with surface water in parts of the basin. Comparison of surface water and regional ground water flow patterns indicate that boundaries for ground water basins typically do not coincide with surface water drainage subbasins. There are several areas in the basin where ground water flow that originates outside of the Suwannee River basin crosses surface water basin boundaries during both low‐flow and high‐flow conditions. In a study area adjacent to the Suwannee River that consists predominantly of agricultural land use, 18 wells tapping the Upper Floridan aquifer and 7 springs were sampled three times during 1990 through 1994 for major dissolved inorganic constituents, trace elements, and nutrients. During a period of above normal rainfall that resulted in high river stage and high ground water levels in 1991, the combination of increased amounts of dissolved organic carbon and decreased levels of dissolved oxygen in ground water created conditions favorable for the natural reduction of nitrate by denitrification reactions in the aquifer. As a result, less nitrate was discharged by ground water to the Suwannee River.

MODELING MACROPORE TRANSPORT OF AGRICULTURAL CHEMICALS ON A RIVER FLOODPLAIN: ATRAZINE TRANSPORT SIMULATION

The United States Geological Survey (USGS) model Variably Saturated Two Dimensional Transport (VS2DT)was used to simulate macropore transport of atrazine through a highly structured clay soil to a sand and gravel floodplainaquifer at a field research site in Burleson County, Texas. A simulation of preferential flow through the surface clay wassuccessfully coupled with a simulation of groundwater flow in a floodplain aquifer. Simulated groundwater flow and atrazinetransport compared favorably with field measured values. The water levels in the floodplain aquifer were primarilyinfluenced by fluctuations in river stage. Simulated groundwater and surface water flows into and out of the aquifer werecalculated. Groundwater discharge from the aquifer to the river averaged 0.023 m3/s/km during low river stages. Surfacewater recharge to the aquifer averaged 0.022 m3/s/km during high river stages. Simulated atrazine transport through theclay soil domain resulted in atrazine losses (percent of total applied) of 7% in 1994 and 15 % in 1995. A pumping test at theresearch site and more rainfall in 1995 than in 1994 resulted in simulated atrazine transport to the bottom of the sand andgravel aquifer (19 m). Atrazine was not transported to the river in groundwater flow during model simulations. Simulatedatrazine concentrations were validated using measured concentrations throughout the study period.

Application and analysis of a coupled surface and groundwater model

A model which couples two-dimensional transient saturated subsurface flow (Boussinesq equation) and one-dimensional gradually-varied unsteady open-channel flow (Saint-Venant equations) is developed and applied to the Truckee River system in northern Nevada. The coupled model involves simultaneous numerical solution of the surface and subsurface flow equations using the Galerkin finite-element method. This paper attempts to address questions regarding the application of such a model to both real and hypothetical hydrologic systems in terms of analysis of parameter sensitivity, predictive uncertainty and uniqueness of model solution. Investigation of parameter sensitivity provides information regarding the relative accuracy with which individual system parameters should be measured in order to insure successful model operation. Model predictive uncertainty is evaluated based on comparison of model output and field observations obtained over a two-year period from the Truckee River study area in northern Nevada. Results indicate fair to good prediction of both high and low river stage and groundwater table elevations with predictive accuracy decreasing with distance away from river channel. A procedure for quantifying uniqueness of model solution is developed to provide insight into the reliability associated with extrapolation of model output beyond the limits of observed field measurements. Based on results for the Truckee River system, such extrapolation appears to be justified.

Bank Erosion in Soils of the Lower Mississippi Valley

Bank erosion along the Lower Mississippi River is dependent on local tendencies of the river to meander and on the geology of riverbank deposits. In the Alluvial Valley, the river erodes its thalweg in sands, and sands and gravels. During the high river stage, bendway pools may be deepened 20 ft to 40 ft or more by seasonal scour. Such periodic erosion may steepen the toes of the banks from stable slopes to unstable slopes that cause subaqueous failures. The subaqueous failures may, in turn, trigger upper bank failures, affecting a layer of cohesive to partly cohesive deposits known as the topstratum. These topstratum deposits respond in certain characteristic manners to oversteepening of the bank slope. In the Deltaic Plain, the river erodes its thalweg chiefly in clays. The surge of water during the high river stage is considerably reduced by distributaries, and erosion is further reduced by the cohesive strength of the clays. Consequently, there is a comparative stability in the river channel.

Oceanography of Mississippi Delta Sedimentary Environments

Oceanography of Mississippi Delta Sedimentary Environments

Purification of Water Supplies

The water supplies west of the Cascades are principally soft, low in alkalinity and with a pH ranging from slightly acid at high river stages, to slightly alkaline at low stages. The color of these waters varies with the rainfall and the amount of tributary swampy area. The turbidities are not high, as a rule, and are usually coarse except where glacial flour is present. After heavy rainfall particularly, turbidities may be present in objectionable amounts. East of the Cascades the waters the waters of the Pacific Northwest are much more alkaline, except those coming from the mountains themselves. They have a greater range of turbidities, and carry considerably more mineral matter. Though the purification of these waters is more necessary, the problem is a simpler one, since the water is more easily coagulated. This paper, therefore, will be limited to a discussion of the problems involved in the purification of the softer waters of the western slope. These are more like the waters of New England than of any other section of the United States, but are less colored and have higher alkalinities. The average water characteristics for a number of streams in Washington, with one analysis from Oregon, are shown in table 1. From this table the general character of the water on both sides of the Cascades can be seen.