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Publications—Scientific Investigations Report |
By Jeffrey R. Deacon, Thor E. Smith, Craig M. Johnston, Richard B. Moore, Rebecca M. Weidman, and Laura J. Blake
U.S. Geological Survey Scientific Investigations Report 2006-5144
AVAILABLE ONLINE ONLY
The body of the report is available in PDF Format ( 19,804 KB)
A study of total nitrogen concentrations and loads was conducted from December 2002 to September 2005 at 13 river sites in the upper Connecticut River Basin. Ten sites were selected to represent contributions of nitrogen from forested, agricultural, and urban land. Three sites were distributed spatially on the main stem of the Connecticut River to assess the cumulative total nitrogen loads. To further improve the understanding of the sources and concentrations and loads of total nitrogen in the upper Connecticut River Basin, ambient surface water-quality sampling was supplemented with sampling of effluent from 19 municipal and paper mill wastewater-treatment facilities.
Mean concentrations of total nitrogen ranged from 0.19 to 2.8 milligrams per liter (mg/L) at river sampling sites. Instantaneous mean loads of total nitrogen ranged from 162 to 58,300 pounds per day (lb/d). Estimated mean annual loads of total nitrogen ranged from 49,100 to 21.6 million pounds per year (lb/yr) with about 30 to 55 percent of the loads being transported during the spring. The estimated mean annual yields of total nitrogen ranged from 1,190 to 7,300 pounds per square mile per year (lb/mi2)/yr.
Mean concentrations of total nitrogen ranged from 4.4 to 30 mg/L at wastewater-treatment sampling sites. Instantaneous mean loads of total nitrogen from municipal wastewater-treatment facilities ranged from 36 to 1,780 lb/d. Instantaneous mean loads of total nitrogen from paper mill wastewater-treatment facilities ranged from 96 to 160 lb/d.
The median concentration of total nitrogen was 0.24 mg/L at forested sites, 0.48 mg/L at agricultural sites, 0.54 mg/L at urban sites, 0.48 mg/L at main-stem sites, and 14 mg/L at wastewater-treatment sites. Concentrations of total nitrogen at forested sites were significantly less than at all other site types (p<0.05). Concentrations of total nitrogen at agricultural, urban, and main stem sites were not significantly different among each other (p>0.05) but were significantly greater (p<0.05) than at forested sites and significantly less than concentrations at wastewater-treatment sites (p<0.05). Total nitrogen concentrations at wastewater-treatment sites were significantly different from all other site types (p<0.05).
Annual yields of total nitrogen ranged from 732 to 1,920 (lb/mi2)/yr at forested sites; 1,550 to 2,980 (lb/mi2)/yr at agricultural sites; 1,280 to 1,860 (lb/mi2)/yr at urban sites that were not directly affected by wastewater effluent; 7,090 to 7,770 (lb/mi2)/yr at an urban site directly affected by wastewater effluent; and 1,300 to 2,390 (lb/mi2)/yr at main-stem sites.
In this study, the mean annual load and yield of total nitrogen at the Connecticut River at Wells River, VT, was estimated at 4.47 million lb/yr and 1,690 (lb/mi2)/yr, respectively. The mean annual load and yield of total nitrogen at the Connecticut River at North Walpole, NH, was estimated at 9.60 million lb/yr and 1,750 (lb/mi2)/yr, respectively. The mean annual load and yield of total nitrogen leaving the upper Connecticut River Basin, as estimated at the Connecticut River at Thompsonville, CT, was 21.6 million lb/yr and 2,230 (lb/mi2)/yr, respectively.
Abstract
Introduction
Purpose and Scope
Previous Studies
Description of the Study Area
Data Collection and Analysis
Site Selection
Sample Collection
Data Analysis
Characterization of Total Nitrogen at River Sampling Sites
Moose River at Victory, VT, Station 01134500
Passumpsic River at Passumpsic, VT, Station 01135500
Connecticut River at Wells River, VT, Station 01138500
Ayers Brook at Randolph, VT, Station 01142500
White River at West Hartford, VT, Station 01144000
Sugar River at West Claremont, NH, Station 01152500
Connecticut River at North Walpole, NH, Station 01154500
Otter River at Otter River, MA, Station 01163200
North River at Shattuckville, MA, Station 01169000
South River near Conway, MA, Station 01169900
Green River near Colrain, MA, Station 01170100
Mill River at Northhampton, MA, Station 01171500
Connecticut River at Thompsonville, CT, Station 01184000
Characterization of Total Nitrogen at Wastewater-Treatment Sampling Sites
Comparison of Total Nitrogen Concentrations and Yields Among Site Types
Summary and Conclusions
References Cited
Appendix A: Supplemental Data
A-1. | Annual loads, yields, and confidence intervals for total nitrogen and total phosphorus for river sampling sites in the upper Connecticut River Basin in New Hampshire, Vermont, and Massachusetts. |
A-2. | Estimates of seasonal total nitrogen load for river sampling sites in the upper Connecticut River Basin in New Hampshire, Vermont, and Massachusetts. |
A-3. | Estimates of seasonal total phosphorus load for river sampling sites in the upper Connecticut River Basin in New Hampshire, Vermont, and Massachusetts. |
A-4. | Regression equations for estimates of total nitrogen load and total phosphorus load for river sampling sites in the upper Connecticut River Basin in New Hampshire, Vermont, and Massachusetts. |
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For further information, contact:
Keith W. Robinson, Director
U.S. Geological Survey
New Hampshire - Vermont Water Science Center
361 Commerce Way
Pembroke, NH 03275
(603) 226-7807
or visit our Web site at: http://nh.water.usgs.gov