Publications—Scientific Investigations Report 2007-5074
By Laura Medalie
U.S. Geological Survey Scientific Investigations Report 2007-5074
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Front Cover (144 KB) Full Report (3,319 KB) Back Cover (144 KB) |
The effectiveness of best-management practices (BMPs) in improving water quality in Lake Champlain tributaries was evaluated from 2000 through 2005 on the basis of analysis of data collected on concentrations of total phosphorus and suspended sediment in Englesby Brook, an urban stream in Burlington, and Little Otter Creek, an agricultural stream in Ferrisburg. Data also were collected on concentrations of total nitrogen in the Englesby Brook watershed. In the winter of 2001–2002, one of three planned structural BMPs was installed in the urban watershed. At approximately the same time, a set of barnyard BMPs was installed in the agricultural watershed; however, the other planned BMPs, which included streambank fencing and nutrient management, were not implemented within the study period.
At Englesby Brook, concentrations of phosphorus ranged from 0.024 to 0.3 milligrams per liter (mg/L) during base-flow and from 0.032 to 11.8 mg/L during high-flow conditions. Concentrations of suspended sediment ranged from 3 to 189 mg/L during base-flow and from 5 to 6,880 mg/L during high-flow conditions. An assessment of the effectiveness of an urban BMP was made by comparing concentrations and loads of phosphorus and suspended sediment before and after a golf-course irrigation pond in the Englesby Brook watershed was retrofitted with the objective of reducing sediment transport. Results from a modified paired watershed study design showed that the BMP reduced concentrations of phosphorus and suspended sediment during high-flow events—when average streamflow was greater than 3 cubic feet per second. While construction of the BMP did not reduce storm loads of phosphorus or suspended sediment, an evaluation of changes in slope of double-mass curves showing cumulative monthly streamflow plotted against cumulative monthly loads indicated a possible reduction in cumulative loads of phosphorus and suspended sediment after BMP construction.
Results from the Little Otter Creek assessment of agricultural BMPs showed that concentrations of phosphorus ranged from 0.016 to 0.141 mg/L during base-flow and from 0.019 to 0.565 mg/L during high-flow conditions at the upstream monitoring station. Concentrations of suspended sediment ranged from 2 to 13 mg/L during base-flow and from 1 to 473 mg/L during high-flow conditions at the upstream monitoring station. Concentrations of phosphorus ranged from 0.018 to 0.233 mg/L during base-flow and from 0.019 to 1.95 mg/L during high-flow conditions at the downstream monitoring station. Concentrations of suspended sediment ranged from 10 to 132 mg/L during base-flow and from 8 to 1,190 mg/L during high-flow conditions at the downstream monitoring station.
Annual loads of phosphorus at the downstream monitoring station were significantly larger than loads at the upstream monitoring station, and annual loads of suspended sediment at the downstream monitoring station were larger than loads at the upstream monitoring station for 4 out of 6 years. On a monthly basis, loads of phosphorus and suspended sediment at the downstream monitoring station were significantly larger than loads at the upstream monitoring station. Pairs of concentrations of phosphorus and monthly loads of phosphorus and suspended sediment from the upstream and downstream monitoring stations were evaluated using the paired watershed study design. The only significant reduction between the calibration and treatment periods was for monthly loads of phosphorus; all other evaluations showed no change between periods.
Abstract
Introduction
Purpose and Scope
Previous Studies
Study Area Description
Study Methods
Site Selection and Study Design
Field Procedures
Laboratory Procedures
Quality Control
Estimation of Loads
Statistical Analysis
Water Quality of the Englesby Brook Watershed
Hydrology
Concentrations of Nutrients and Suspended Sediment
Loads of Nutrients and Suspended Sediment
Comparison of Nitrogen and Phosphorus Yields at Englesby Brook with Other Urban Watersheds
Evaluation of the Effect of a BMP in the Water Quality of Englesby Brook
Water Quality of the Little Otter Creek Watershed
Hydrology
Concentrations of Phosphorus and Suspended Sediment
Loads of Phosphorus and Suspended Sediment
Phosphorus and Suspended-Sediment Export from a Dairy Farm
Evaluation of the Effect of Barnyard BMPs in the Water Quality of Little Otter Creek
Effect of Land Use on Phosphorus Yields in the Lake Champlain Basin
Summary and Conclusions
References Cited
1–3. Maps showing—
1. Location of Englesby Brook and Little Otter Creek study areas in the Lake Champlain Basin
2. Land use and location of streamflow-gaging and water-quality monitoring station in the Englesby Brook watershed, Vermont
3. Land use and location of streamflow-gaging and water-quality monitoring stations on Little Otter Creek, Vermont
4–5. Photographs showing—
4. Sampling station on Englesby Brook, showing weir and conduit for automated sampler line leading up to streamflow-gaging station
5. View upstream from Middlebrook Road bridge near downstream monitoring station on Little Otter Creek, Vermont
6. Graph showing annual cumulative streamflow curves for Englesby Brook, water years 2000–2005
7. Bar chart showing monthly precipitation at the South Burlington Airport National Weather Service station
8–22. Graphs showing—
8. Base-flow concentrations of total nitrogen, total phosphorus, and suspended sediment at Englesby Brook, water years 2000–2005
9. Concentrations of total nitrogen, total phosphorus, and suspended sediment for selected storms at Englesby Brook
10. Annual loads of total nitrogen, total phosphorus, and suspended sediment from high-flow and base-flow contributions, mean annual streamflow, and total precipitation at Englesby Brook, water years 2000–2005
11. Monthly loads of total nitrogen, total phosphorus, and suspended sediment, estimated using two methods, at Englesby Brook, water years 2000–2005
12. Mean loads by month for total nitrogen, total phosphorus, and suspended sediment at Englesby Brook, water years 2000–2005
13. Quartiles and median yields of total nitrogen and total phosphorus from selected urban streams in New England
14. Quartiles and median concentrations of total phosphorus and suspended sediment for base-flow samples during the calibration and the treatment period at Englesby Brook
15. Mean storm concentrations of total phosphorus and suspended sediment plotted against mean storm streamflow for measured storms during the calibration and the treatment period at Englesby Brook
16. Storm loads of total phosphorus and suspended sediment plotted against total stormwater volume for measured storms during the calibration and the treatment period at Englesby Brook
17. Double-mass curves for cumulative monthly streamflow and cumulative monthly loads of total phosphorus and suspended sediment at Englesby Brook, water years 2000–2005
18. Annual cumulative streamflow curves for Little Otter Creek, water years 2000–2005
19. Base-flow concentrations of total phosphorus and suspended sediment at upstream and downstream monitoring stations on Little Otter Creek, water years 2000–2005
20. Concentrations of total phosphorus and suspended sediment for selected storms at upstream and downstream monitoring stations, Little Otter Creek
21. Annual loads of total phosphorus and suspended sediment from high-flow and base-flow contributions for upstream and downstream monitoring stations on Little Otter Creek, mean annual streamflow at USGS streamflow-gaging station 04282650, and total precipitation, water years 2000–2005
22. Mean loads by month for total phosphorus and suspended sediment at upstream and downstream monitoring stations on Little Otter Creek, water years 2000–2005
| 23. | Scatterplots and regression equations comparing calibration and treatment periods from paired watershed ANCOVA for concentrations of phosphorus and monthly loads of phosphorus and suspended sediment from upstream and downstream monitoring stations at Little Otter Creek |
| 24. | Graph showing quartiles and median yields of total phosphorus from major subbasins in the Lake Champlain Basin (excluding the Pike River subbasin in Canada), Vermont and New York, water years 2002–2004 |
Medalie, Laura, 2007, Concentrations and loads of nutrients and suspended sediments in Englesby Brook and Little Otter Creek, Lake Champlain Basin, Vermont, 2000–2005: U.S. Geological Survey Scientific Investigations Report 2007–5074, 50 p.
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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
or visit our Web site at:
http://nh.water.usgs.gov
U.S. Department of the Interior | U.S. Geological Survey
URL: http://pubs.usgs.gov/sir/2007/5074/
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Page Last Modified: Thursday, 28-Sep-2007 13:25:10 EDT
