1. What’s in Your Watershed? Fall and Virgil Creeks
Volunteer-CSI Monitoring Partnership
Tracks Water Quality
Wednesday, January 15, 2014, 6:30 PM
Tompkins County Public Library
Steve Penningroth, Community Science Institute

2. Cayuga Lake Watershed: CSI Monitoring Sites

3. Interactive Water Quality Database
CSI has partnered with volunteer groups to track water quality since 2002
Results are organized in CSI’s open online database by “monitoring set” (*)
Database can be searched and search results downloaded free of charge (*)
Data can be combined with USGS flow data to estimate phosphorus loads

4. Phosphorus and Sediment Loading to the South End of Cayuga Lake
Source
Average Total Suspended Solids (tons/year)
Data through 2010
% Total
IAWWTP 53 0%
CHWWTP 30
LSC
Not measured
n/a
Fall Creek
28,165
57%
Cayuga Inlet
(Six Mile Creek)
20,917 (9,884)
43% (20%)
Source
Average Orthophosphate (PO4) (tons P/year) *Data through 2013
% Total
IAWWTP
~0.5
~6%
CHWWTP
Not measured
n/a
LSC
0.22 3%
Fall Creek*
3.93*
48%*
Cayuga Inlet*
(Six Mile Creek*)
3.47* (1.36*)
43%* (17%*)
Source
Average Total Phosphorus (tons P/year) *Data through 2013
% Total
IAWWTP
2.99 6%
CHWWTP
1.64 4%
LSC
0.42 1%
Fall Creek*
22.49*
45%*
Cayuga Inlet*
(Six Mile Creek*)
22.76* (9.56*)
45%* (19%*)

5. Why are Phosphorus Loads Important?
South end of Cayuga Lake is on DEC’s and EPA’s 303(d) list of impaired water bodies
Under federal Clean Water Act, remediation requires reduction of phosphorus loads
Load reduction is based on limits called Total Maximum Daily Loads, or TMDLs
Cornell University’s Cayuga Lake Modeling Project from 2013 to 2017 is designed to provide DEC and EPA with phosphorus data to develop TMDLs

6. How To Estimate Phosphorus Loads? Monitoring vs. Modeling
Phosphorus loads based on monitoring
CSI-volunteer monitoring partnerships collect water samples and produce “on the ground” phosphorus data year in and year out
Phosphorus data are combined with flow data from USGS gauging stations to calculate loads using USGS software called LOADEST
Phosphorus loads based on modeling
The Cayuga Lake Modeling Project will use a mathematical model to simulate loading based on a number of inputs, for example, land use, soil type, and precipitation
Cornell’s loading model will be calibrated using “on the ground” data collected in 2013 by their contractor, Upstate Freshwater Institute
Model will be validated against “on the ground” data collected before and after 2013, such as CSI-volunteer monitoring data
Finished model will be used by DEC to guide development of TMDL

7. Issues Around a Phosphorus TMDL
TMDLs are designed for point sources, but CSI’s data indicate ~90% of phosphorus that is loaded to the south end of Cayuga Lake comes from non-point sources in watersheds of tributary streams
Nature and degree of impairment are debatable:
- Swimming has not been permitted at Stewart Park since the 1960s due to turbidity (muck), and it is questionable whether a phosphorus TMDL could address this problem
- Total phosphorus on southern shelf averages around the 20 ppb threshold of eutrophication

8. TMDL Issues (cont’d)
Studies suggest that a significant part of the turbidity at the south end of Cayuga Lake is caused by suspended mineral particles such as clay and calcium carbonate
Studies show there is little, if any, correlation between algae growth (chlorophyll a) and phosphorus levels at the south end of Cayuga Lake