Long Island Sound Prospects for the Urban Sea- John Mullaney Chapter 5: Metals, Organic Compounds, and

Nutrients in Long Island Sound: Sources, Magnitudes, Trends, and Impacts

USGS was asked to summarize nutrient trends from the major fall line stations where we have long-term water quality data.

Point Source Loads in Decline in Long Island Sound Management Zones

Wet Deposition of Nitrogen to the

Long Island Sound watershed has

declined

Total Nitrogen7 major fall line stations combined

Methods:Fluxmaster

Monotonic adjustment for changes in flow

Schwarz GE, Hoos AB, Alexander RB, Smith RA. The SPARROW Surface Water-Quality Model: Theory, Application and User Documentation. 2006. U.S. Geological Survey, Techniques and Methods Report, Book 6, Chapter B3, Reston, Virginia

Phosphorus and Changing Nutrient Ratios

Total Phosphorus TN/TP

U.S. Department of the InteriorU.S. Geological Survey

The Use of EGRET Package for R on Trends in Nutrient and Chloride Concentrations and Loads, in the Long Island Sound Basin

Quinebaug

Quinebaug (JC)

Shetucket

Hockanum

Connecticut

Farmington

Salmon

Quinnipiac

Bunnell

Unionville

Naugatuck

Housatonic

Saugatuck

NorwalkIn cooperation with the U.S. EPA Office of Long Island Sound and Connecticut DEEP

John MullaneyBob Hirsch

Objective

Evaluate trends in concentrations and loads of nitrogen, phosphorus, total organic carbon and silica, in the major tributaries of Long Island Sound, using a method that incorporates changes in streamflow during the study period This information is important in understanding the

effects of management action on Long Island Sound, and formulating an updated nitrogen TMDL

Large decreases in point source loads of nitrogen

From Mullaney and Schwarz, 2013

Nitrogen loads flat or slight increase

Reasons for this study:

Approach-EGRET overview• Ingests water quality sample data, daily streamflow data, and

meta data from USGS Web services or from user-supplied files

• Sub-systems: WRTDS* for river water quality data analysis and flowHistory for analysis of streamflow alone

• Goal: Exploration of the data to describe the evolving hydrologic system. Produce: graphs, summary statistics, understanding, and hypotheses. EGRET also contains a module on “FLOW HISTORY”

• (New “edge adjust” version being used for this project)

*Weighted Regressions on Time, Discharge, and Season (WRTDS), with an application to Chesapeake Bay River inputs, 2010, Hirsch, Robert M.; Moyer, Douglas L.; Archfield, Stacey A., Journal of the American Water Resources Association, 46: 857 - 880

Changes in Mean Daily Flow, 2001-2013(percent)- Flow History Module in EGRET

Station Water years Annual Winter Spring Summer Fall1

Shetucket 2001 2013 5.8 1.5 -1.1 20 -0.97 Quinebaug(Q) 2001 2013 8.1 6.6 -4.1 22 -3.8 Quinebaug(JC) 2001 2013 4.1 -0.24 -3.7 17 -3.4 Connecticut 2001 2013 8.6 10 -1.5 20 -1.3 Bunnell 2001 2013 8.7 8.3 -3.7 27 -3.4 Farmington(U) 2001 2013 15 18 2 16 1.8 Farmington(T) 2001 2013 10 13 -0.81 14 -0.74 Hockanum 2001 2013 10 5.9 3.6 17 3.3 Salmon 2001 2013 9.8 4 4.7 21 4.2 Quinnipiac 2001 2013 9.7 9.8 3.3 17 3 Housatonic 2001 2013 11 12 -3.9 19 -3.5 Naugatuck 2001 2013 6.4 6.7 -4.1 17 -3.8 Saugatuck 2001 2013 11 12 3.1 14 2.8 Norwalk 2001 2013 9.4 10 0.3 19 0.26 1. Fall analysis for water years 2001-2012

Total Nitrogen Flux- WRTDSGreen line is the flow-normalized

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