Environmental and Water Quality Operational Studies. Morphologic Effects of Lower Mississippi River Dike Fields PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Environmental and Water Quality Operational Studies. Morphologic Effects of Lower Mississippi River Dike Fields PDF full book. Access full book title Environmental and Water Quality Operational Studies. Morphologic Effects of Lower Mississippi River Dike Fields by Nelson R. Nunnally. Download full books in PDF and EPUB format.
Author: Nelson R. Nunnally Publisher: ISBN: Category : Languages : en Pages : 76
Book Description
Dikes are used extensively on large, meandering rivers to help maintain navigation channels. Dike fields alter flow velocities and sedimentation patterns, thereby affecting river morphology and the amount and quality of aquatic habitat. Some investigators have theorized that sedimentation induced by the dike fields constructed on the lower Mississippi, largely since 1960, is altering river morphology and aquatic hatibat in a manner similar to the changes that have been observed in the lower Missouri. Others are of the opinion that dike fields on the lower Mississippi do not typically fill completely with sediment, and the pools they contain have increased the amount of slack-water habitat. Low-water photographs taken in 1962 and 1976 and comprehensive hydrographic surveys done in 1962-64 and 1974-75 were used to measure morphologic changes in diked and undiked reaches. River surface area between river miles 320 and 954 was classified as main channel, secondary channel, slough, chute, or pool. The 1962 and 1976 areas in each category were measured from the photographs. River stage at time of photography averaged about 2 ft (0.6 m) lower in 1976, so 1976 measurements were adjusted for stage differential, based on width mesurements taken from the hydrogaphic surveys. Results were summarized for diked and undiked reaches.
Author: Nelson R. Nunnally Publisher: ISBN: Category : Languages : en Pages : 76
Book Description
Dikes are used extensively on large, meandering rivers to help maintain navigation channels. Dike fields alter flow velocities and sedimentation patterns, thereby affecting river morphology and the amount and quality of aquatic habitat. Some investigators have theorized that sedimentation induced by the dike fields constructed on the lower Mississippi, largely since 1960, is altering river morphology and aquatic hatibat in a manner similar to the changes that have been observed in the lower Missouri. Others are of the opinion that dike fields on the lower Mississippi do not typically fill completely with sediment, and the pools they contain have increased the amount of slack-water habitat. Low-water photographs taken in 1962 and 1976 and comprehensive hydrographic surveys done in 1962-64 and 1974-75 were used to measure morphologic changes in diked and undiked reaches. River surface area between river miles 320 and 954 was classified as main channel, secondary channel, slough, chute, or pool. The 1962 and 1976 areas in each category were measured from the photographs. River stage at time of photography averaged about 2 ft (0.6 m) lower in 1976, so 1976 measurements were adjusted for stage differential, based on width mesurements taken from the hydrogaphic surveys. Results were summarized for diked and undiked reaches.
Author: Bruce M. Sabol Publisher: ISBN: Category : Aquatic biology Languages : en Pages : 104
Book Description
The main channel was characterized by high current velocities, high suspended solids, low light penetration, relatively high nutrient concentrations, generally low chlorophyll and zooplankton concentrations, stable and slightly alkaline pH levels, and stable oxygen saturation (approx. 90 percent). Detrital particulate organic matter (POM) comprised over 80 percent of the total POM for all sampling periods except August when algal POM comprised over half the total. The abandoned channel was characterized by quiescent, generally stratified eutrophic waters low in suspended solids and high in chlorophyll and zooplankton concentrations with moderately fluctuating pH levels and widely fluctuating oxygen saturation levels. Water quality and planktoon conditions observed in the secondary channel were indistinguishable from the main channel during periods of flow. During quiescent periods, suspended solids and turbidity decreased although other variables showed no appreciable difference from the main channel. Dike fields were transient lentic environments. During lotic periods, water quality was indistinguishable from the main channel. During isolations from the main channel, water clarity increased, soluble nutrients decreased, chlorophyll and zooplankton concentrations increased, and high pH and oxygen saturation levels were often observed. During the long period of isolation from the main channel, the dike fields became increasingly different from the main channel and from one another.
Author: Michael P. Farrell Publisher: ISBN: Category : Aquatic ecology Languages : en Pages : 44
Book Description
To expedite the research data management system (RDMS) required for complex and large-scale ecological field studies being done at the U.S. Army Engineer Waterways Experiment Station (WES), a graphical display system was developed. The Statistical Analysis System (SAS) provides the framework for making open-ended RDMS practical and cost-effective. PROC VIVIPLOT is the first of a series of SAS procedures that will produce copy-ready figures with some independence as to choice of plotter. Several approaches are available that minimize errors in coding variables. Numeric codes, 'smart codes, ' with embedded information allocated to positions within the value codes are widely used but unacceptable for variables with many values and/or many levels of classification. 'Nonsense' codes, or codes without embedded information, however, efficiently circumvent the problems associated with smart codes. Using nonsense codes, alphanumeric variable values are assigned a sequential numeric code as new values are encountered in the data base, irrespective of the position of the value in the classification scheme for that variable. With the use of nonsense codes, the management approach is open-ended and does not require a knowledge of the number of potential classification levels for the variables. In addition, experience with several large environmental data bases indicates that coding errors appear to be less frequent using nonsense codes than in those studies in which a smart code approach was used.
Author: Nelson R. Nunnally
Author: Nelson R. Nunnally
Author: Nelson R. Nunnally
Author: Nelson R. Nunnally
Author: 
Author: 
Author: Bruce M. Sabol
Author: Stephen P. Cobb
Author: Casey M. Mayne
Author: 
Author: Michael P. Farrell