| Abstract: | Dissolved oxygen is a critical constituent in reservoirs and lakes because it is essential for metabolism by all aerobic aquatic organisms. In general, hypolimnetic temperature and dissolved-oxygen concentrations vary from summer to summer in reservoirs, more so than in natural lakes, largely in response to the magnitude of flow into and release out of the water body. Because eutrophication is often defined as the acceleration of biological productivity resulting from increased nutrient and organic loading, hypolimnetic oxygen consumption rates or deficits often provide a useful tool in analyzing temporal changes in water quality.
This report updates a previous report that evaluated hypolimnetic dissolved-oxygen dynamics for a 21-year record (1974-94) in Beaver, Table Rock, Bull Shoals, and Norfork Lakes, as well as analyzed the record for Greers Ferry Lake. Beginning in 1974, vertical profiles of temperature and dissolved-oxygen concentrations generally were collected monthly from March through December at sites near the dam of each reservoir. The rate of change in the amount of dissolved oxygen present below a given depth at the beginning and end of the thermal stratification period is referred to as the areal hypolimnetic oxygen deficit. Areal hypolimnetic oxygen deficit was normalized for each reservoir based on seasonal flushing rate between April 15 and October 31 to adjust for wet year and dry year variability.
Annual cycles in thermal stratification within Beaver, Table Rock, Bull Shoals, Norfork, and Greers Ferry Lakes exhibited typical monomictic (one extended turnover period per year) characteristics. Flow dynamics drive reservoir processes and need to be considered when analyzing areal hypolimnetic oxygen deficit rates. A nonparametric, locally weighted scatter plot smooth line describes the relation between areal hypolimnetic oxygen deficit and seasonal flushing rates, without assuming linearity or normality of the residuals.
The results in this report are consistent with earlier findings that oxygen deficit rates and flushing-rate adjusted areal hypolimnetic oxygen deficit in Beaver and Table Rock Lakes were decreasing between 1974 and 1994. The additional data (1995-2008) demonstrate that the decline in flushing-rate adjusted areal hypolimnetic oxygen deficit in Beaver Lake has continued, whereas that in Table Rock Lake has flattened out in recent years. The additional data demonstrate the flushing-rate adjusted areal hypolimnetic oxygen deficit in Bull Shoals and Norfork Lakes have declined since 1995 (improved water quality), which was not indicated in earlier studies, while Greers Ferry Lake showed little net change over the period of record. Given the amount of data (35 years) for these reservoirs, developing an equation or model to predict areal hypolimnetic oxygen deficit and, therefore, areal hypolimnetic oxygen content, on any given day during future stratification seasons may be useful for reservoir managers. |
| Genre: | USGS Numbered Series |
| ProdID: | 70004960 |
| Citation Author: | De Lanois, Jeanne L. ; Green, W. Reed |
| Citation Contributing Office: | Arkansas Water Science Center |
| Citation Datum: | North American Vertical Datum of 1988, North American Datum of 1983 |
| Citation Day: | |
| Citation Edition: | |
| Citation Editor: | |
| Citation End Page: | 15 |
| Citation Issue: | |
| Citation Keywords: | |
| Citation Language: | English |
| Citation Larger Work Title: | |
| Citation LatN: | 0373000 |
| Citation LatS: | 0350000 |
| Citation LonE: | -0910000 |
| Citation LonW: | -0940000 |
| Citation Month: | |
| Citation No Pagination: | |
| Citation Number Of Pages: | 15 |
| Citation Online Only Flag: | Y |
| Citation Phsyical Description: | iv, 15 p.; Appendices: Beaver Lake, Table Rock Lake, Bull Shoals Lake, Norfolk Lake, Greers Ferry Lak- |
| Citation Projection: | Universal Transverse Mercator |
| Citation Public Comments: | Prepared in cooperation with the U.S. Army Corps of Engineers, Southwest Power Administration, and the Arkansas Game and Fish Commission |
| Citation Publisher: | U.S. Geological Survey |
| Citation Series: | Scientific Investigations Report |
| Citation Series Code: | SIR |
| Citation Series Number: | 2011-5090 |
| Citation Search Results Text: | Hypolimnetic dissolved-oxygen dynamics within selected White River reservoirs, northern Arkansas-southern Missouri, 1974-2008; 2011; SIR; 2011-5090; De Lanois, Jeanne L. ; Green, W. Reed |
| Citation Start Page: | 1 |
| Citation Volume: | |
| Citation Year: | 2011 |
| Type: | citation/reference |
| Text: | Hypolimnetic dissolved-oxygen dynamics within selected White River reservoirs, northern Arkansas-southern Missouri, 1974-2008; 2011; SIR; 2011-5090; De Lanois, Jeanne L. ; Green, W. Reed |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/sir_2011_5090.gif |
| URL (INDEX PAGE): | http://pubs.usgs.gov/sir/2011/5090/ |
| Date Other: | Tue, 26 Jul 2011 00:00 -0500 |
| Publisher: | U.S. Geological Survey |
