 |
|
|
||||
| Publications—Scientific Investigations Report |
By Jonathan Morrison and Michael J. Colombo
U.S. Geological Survey Scientific Investigations Report 2006-5272
The body of the report is available in PDF Format (1,158 KB)
Water quality was characterized at three tributary watersheds
to the Nepaug Reservoir—Nepaug River, Phelps Brook, and Clear Brook—from October 1998 through September 2001 to document existing water-quality conditions and evaluate potential future effects of the removal of sand and gravel from areas of the watershed. Some removal operations may include removal of vegetation and top soil and steepening of slopes. Routine water samples collected monthly in all three watersheds
were analyzed for nutrients, organic carbon, major ions, and fecal indicator bacteria. Results of the analyses indicate that, in general, the water quality in all three tributary watersheds
is good and meets standards established for drinking-water supplies for nitrate, but does not always meet contact-recreation
standards for bacteria. Median concentrations of total nitrogen, total phosphorus, and total organic carbon were highest
in the routine monthly samples from Phelps Brook and lowest
from Clear Brook. Samples also were collected during selected storms to examine changes in concentrations of nutrients
during periods of high streamflow. The maximum values measured for total nitrogen, total phosphorus, and total organic carbon were in storm samples from Clear Brook.
The Nepaug River watershed delivered the largest loads of total nitrogen, total phosphorus, and total organic carbon to the reservoir. Yields of nutrients and organic carbon differed significantly
from year to year and among the three watersheds. Yields of total nitrogen and total organic carbon were largest from Phelps Brook and smallest from Clear Brook. The yields of total phosphorus were largest from Nepaug River and smallest
from Phelps Brook. In comparison to other watersheds in Connecticut, annual loads and yields from the three streams were lower than those of developed urban areas and comparable to those of other rural and forested basins. Delivery of nutrients and organic carbon to the reservoir took place mostly during the spring with the exception of those constituents delivered during Tropical Storm Floyd, a large fall storm.
Abstract
Introduction
Purpose and Scope
Previous Studies
Description of the Study Area
Methods of Data Collection and Analysis
Precipitation Measurements
Streamflow Measurements
Water-Quality Sampling
Water-Quality Data Analysis
Load Estimation
Precipitation, Streamflow, and Runoff in the Nepaug Reservoir Watershed
Surface-Water Quality in the Nepaug Reservoir Watershed
Physical and Chemically Related Properties
Major Inorganic Constituents
Nitrogen, Phosphorus, and Organic Carbon
Fecal Indicator Bacteria
Surface-Water Quality During Storms in the Nepaug Reservoir Watershed
Storm Samples Collected by Automated and Manual Methods
Physical and Chemically Related Properties
Phosphorus, Nitrogen, and Organic Carbon
Storm Samples Collected by Automated Composite Methods
Data from Continuous Monitors
Nutrient Loads and Yields to the Nepaug Reservoir
Nitrogen Loads and Yields
Phosphorus Loads and Yields
Organic Carbon Loads and Yields
Limitations of the Nutrient Load Models
Comparison of Yields in the Nepaug Reservoir Watershed to Other Watersheds in Connecticut
Summary and Conclusions
Acknowledgments
References Cited
2–12. Graphs showing:
| 2. | Precipitation at Burlington, Connecticut, water years 1999-2001 |
| 3. | Streamflow at three U.S. Geological Survey stations indicating dates and flow conditions when water samples were collected, water years 1999-2001: A, station 01187800 Nepaug River near Nepaug, Connecticut; B, station 01187830 Phelps Brook near Collinsville, Connecticut; and C, station 01187850 Clear Brook near Collinsville, Connecticut |
| 4. | Streamflow in A, Nepaug River and Clear Brook; and B, Phelps Brook and Clear Brook, adjusted by size of drainage basin, for water years 1999-2001 |
| 5. | Flow-duration curves showing streamflow normalized by drainage area at three U.S. Geological Survey stations during the study period and the long-term period of record: A, station 01187800 Nepaug River near Nepaug, Connecticut; B, station 01187830 Phelps Brook near Collinsville, Connecticut; and C, station 01187850 Clear Brook near Collinsville, Connecticut |
| 6. | The distribution of the concentrations of A, fecal coliform bacteria; and B, enterococci bacteria, Nepaug Reservoir watershed, Connecticut |
| 7. | The distribution of the concentrations of fecal coliform bacteria by season at three U.S. Geological Survey stations, 1999-2001: A, station 01187800 Nepaug River near Nepaug, Connecticut; B, station 01187830 Phelps Brook near Collinsville, Connecticut; and C, station 01187850 Clear Brook near Collinsville, Connecticut |
| 8. | The distribution of the concentrations of enterococci bacteria by season at three U.S. Geological Survey stations, 1999-2001: A, station 01187800 Nepaug River near Nepaug, Connecticut; B, station 01187830 Phelps Brook near Collinsville, Connecticut; and C, station 01187850 Clear Brook near Collinsville, Connecticut |
| 9. | Continuous water-quality-monitoring data and concentration of total phosphorus at two U.S. Geological Survey stations: A, station 01187800 Nepaug River near Nepaug, Connecticut; and B, station 01187830 Phelps Brook near Collinsville, Connecticut, March 10-14, 2000 |
| 10. | Continuous water-quality-monitoring data and concentration of total phosphorus at A, station 01187850 Clear Brook near Collinsville, Connecticut; and B, station 01187800 Nepaug River near Nepaug, Connecticut, May 19-21, 1999 |
| 11. | Relation of total phosphorus to turbidity at three U.S. Geological Survey stations: A, station 01187800 Nepaug River near Nepaug, Connecticut; B, station 01187830 Phelps Brook near Collinsville, Connecticut; and C, station 01187850 Clear Brook near Collinsville, Connecticut |
| 12. | Continuous water-quality-monitoring data, U.S. Geological Survey station 01187850 Clear Brook near Collinsville, Connecticut, September 14-21, 1999 |
If you have Adobe® Acrobat® or Adobe® Acrobat® Reader® installed on your computer, you may view and print the PDF version of this report. Acrobat Reader, is a free download from Adobe Systems, Inc. Users with disabilities can view information concerning accessibility at access.Adobe.com .
For further information, contact:
Virginia deLima, Director
Connecticut Water Science Center
101 Pitkin St.
East Hartford, CT 06108
Phone: (860) 291-6741
Email: dc_ct@usgs.gov
Web site: http://ct.water.usgs.gov
| AccessibilityFOIAPrivacyPolicies and Notices | |
  |
|