HomeMy WebLinkAboutMemo - Mail Packet - 7/25/2017 - Memorandum From Jared Heath Re: 2017 Spring Water Quality Update - Upper Cache La Poudre WatershedUtilities
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700 Wood Street
PO Box 580
Fort Collins, CO 80522
970.221.6700
970.221.6619 – fax
970.224.6003 – TDD
utilities@fcgov.com
fcgov.com/utilities
M E M O R A N D U M
DATE: July 14, 2017
TO: Mayor Troxell and Councilmembers
FROM: Jared Heath, Watershed Specialist
THRU: Darin Atteberry, City Manager
Kevin R. Gertig, Utilities Executive Director
RE: 2017 Spring Water Quality Update – Upper Cache la Poudre Watershed
Bottom Line:
In the shared interest of monitoring the Upper Cache la Poudre (Upper CLP) River drinking water supply,
the City of Fort Collins, the City of Greeley, and the Tri-Districts partnered in 2008 to implement the
Upper CLP Collaborative Watershed Monitoring Program. The overarching goal of this monitoring effort
is to assist the participants in meeting current and future drinking water treatment goals by reporting
current water quality conditions and trends within the Upper CLP watershed. The attached water quality
update provides a brief summary of snowpack and streamflow, and water quality conditions monitored in
the Upper CLP watershed during the spring months of April, May, and June in 2017.
Background:
The seasonal water quality updates are designed to inform the Upper CLP Watershed Collaborative
Monitoring Program partners, their customers, and other community stakeholders about the condition of
our source watershed and the quality of the raw drinking water supply. This seasonal reporting effort
began in 2015 to provide a succinct and timely summary of current-year conditions in the Upper CLP
Watershed. Seasonal updates are published for the spring, summer, and fall seasons. In depth water
quality reporting is done through annual and five-year technical reports. All water quality reports and
seasonal updates are made publicly available on the Fort Collins Utilities website,
fcgov.com /source-water-monitoring.
Spring 2017 Highlights:
The Upper CLP watershed continues to be a reliable, high quality drinking water source. Water quality
during snowmelt runoff in the spring is typically more variable than other times of the year. Normal
water quality conditions were observed throughout the Upper CLP watershed during the 2017 snowmelt
runoff season.
CC: Carol Webb, Water Resources and Treatment Operations Manager, Utilities
Jill Oropeza, Water Quality Services Manager, Utilities
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Water Quality Update | Spring 2017
fcgov.com/water-quality
Monitoring and Protecting Our Water Sources
SOURCE WATER MONITORING
JWC - Joe Wright Creek above the confl uence with the Poudre River
PJW - Poudre River above the confl uence with Joe Wright Creek
PBR - Poudre River below the Town of Rustic
PSF - Poudre River below the confl uence with the Little South Fork
PNF - Poudre River above the confl uence with the North Fork at the
City of Fort Collins’ Intake
PBD - Poudre River below the confl uence with the North Fork at the
Bellvue Diversion
The Upper Cache la Poudre (UCLP)
Watershed Collaborative Monitoring
Program was established in 2008
between the City of Fort Collins, the City
of Greeley and Soldier Canyon Water
Authority, to help meet
present and future drinking water
treatment goals.
Water quality monitoring of our raw,
Cache la Poudre River drinking water supply
is conducted from April through November.
Monitoring sites are strategically located throughout
the UCLP. Water quality data provide valuable
information about the health of our source
watershed and raw water supply.
The Spring 2017 Water Quality Update provides
a seasonal summary of watershed conditions
in the Upper CLP Watershed by highlighting
snowpack and streamfl ow conditions, as well
as water quality information collected over the
months of April, May and June.
Water quality during snowmelt runoff is highly
variable and to better capture this seasonal
variability, monitoring is conducted two times
per month from April through June. Results
are reported for six key monitoring sites located
throughout the Upper Cache la Poudre watershed,
which capture water quality conditions above and
below major tributaries and near water supply
intake structures (Figure 1).
More information is available at
fcgov.com/source-water-monitoring.
Figure 1 - Upper Cache la Poudre Collaborative Monitoring Program
sampling locations
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Snow water equivalent (SWE), the amount of water held in the snowpack, measured at Joe Wright snow telemetry
station near Cameron Pass was below the long-term median during the start of the snow accumulation season. In
normal years the snowpack begins to develop in October and steadily accumulate through April. Dry and warm
conditions that began in the summer of 2016 persisted through the months of October and early November with the
snow accumulation season beginning nearly six weeks later than normal.
Steady storms beginning in mid-November through December brought the snowpack back to near normal
conditions. A strong storm during the fi rst week of January increased the amount of water in the snowpack from
7.6 inches to 12.8 inches leaving the snowpack well above normal (Figure 2a). The water content in the snowpack
remained above normal through February, but the rate of accumulation during these months was slower than
normal resulting in near normal conditions by early March. Variably dry and wet conditions beginning in March
resulted in periods of snowmelt and snow accumulation cycles before the water content peaked in May.
The maximum amount of water contained in the snowpack, referred to as peak SWE, at Joe Wright SNOTEL was
measured on May 4 at 19.5 inches – 83 percent of the historical median (Figure 2a). Based on the 30 year period
of record, peak SWE at Joe Wright SNOTEL normally occurs on April 29. Peak SWE varied throughout the Upper
CLP watershed (Figure 3). The North Fork and Mainstem Poudre were near the historic median, while the Little
South Fork watershed measured below the historic median. Peak SWE for the Upper CLP basin was measured at
103 percent of the median for the 2017 water year.
Water Quality Update | Spring 2017
fcgov.com/water-quality
SNOWPACK AND STREAMFLOW CONDITIONS
Figure 2 – Snowpack (a) and streamfl ow (b) conditions in
the Poudre River watershed over the 2017 water year.
Sep
Aug
Jul
Jun
May
Apr
Mar
Feb
Jan
Dec
Nov
Oct
20
15
10
5
0
WATERYEAR
SWE (inches)
Median (1981-2010)
WY2017
Explanation
a) Cache la Poudre SnowWater Equivalent at Joe Wright
Sep
Aug
Jul
Jun
May
Apr
Mar
Feb
Jan
Dec
Nov
Oct
3000
2000
1000
Water Quality Update | Spring 2017
fcgov.com/water-quality
SNOWPACK AND STREAMFLOW CONDITIONS
Figure 3 - Percent of median peak snow water equivalent at snow monitoring sites throughout the
Upper Cache la Poudre River watershed.
Snowmelt runoff began in early May, which was slightly later than normal. Streamfl ow, as measured at the Canyon
Mouth, followed closely to the historic average.
A late winter storm in May delivered signifi cant snow to the mid and lower elevations of the North Fork and Main-
stem watersheds. This storm was followed by warmer weather and a rain-on-snow event which accelerated snow-
melt causing a rapid rise and initial peak in streamfl ow. Streamfl ow increased from about 1,000 cubic feet per sec-
ond (cfs) to 2,500 cfs in seven days. Streamfl ow receded following this event, but quickly increased from snowmelt
occurring higher in the watershed.
Peak streamfl ow (daily average) was observed on June 11 at 3,140 cfs – 157 percent of the average peak stream-
fl ow. The snowpack at Joe Wright SNOTEL was completely melted by June 16 and by the June 20 monitoring event,
streamfl ow had receded to normal streamfl ow levels (Figure 2b).
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The Upper Cache la Poudre Collaborative Water Quality Monitoring Program tests for several key water quality
indicators, including pH, conductivity, temperature and turbidity (Table 1). These key measurements provide a
snapshot of water quality conditions, which are useful to identify trends or changes in water quality. Signifi cant
changes in water quality may provide an early warning of potential water pollution.
Water Quality Update | Spring 2017
fcgov.com/water-quality
WATER QUALITY INDICATORS
Temperature Water temperature infl uences other water quality parameters and is a major driver
of biological activity and algal growth in rivers, including certain phytoplankton
species that produce the taste and odor compound, geosmin.
Water Quality Indicator Explanation
pH pH is an important water quality parameter to monitor, as it infl uences the
solubility and biological availability of chemical constituents, including nutrients
and heavy metals. pH near 7 is considered neutral, with more acidic conditions
occurring below 7 and more basic, or alkaline, conditions occurring above 7.
Specifi c Conductivity Conductivity is an index of dissolved ionic solids in water. Hardness is an index of
the total calcium (Ca) and magnesium (Mg) in water.
Turbidity Turbidity is monitored to track changes in water clarity. Clarity is infl uenced by the
presence of algae and/or suspended solids introduced to surface waters through
various land use activities, including runoff and erosion, urban stormwater
runoff and drainage from agricultural lands. For water treatment, turbidity is
an important indicator of the amount of suspended material that is available
to harbor pollutants, such as heavy metals, bacteria, pathogens, nutrients and
organic matter.
Spring water quality monitoring captures water quality conditions throughout
snowmelt runoff and peak streamfl ow. Water quality conditions vary with changes
in elevation and contributing watershed area. All water quality indicators at
key sites reported near the long-term median, indicating normal water quality
conditions on the Poudre River during the 2017 snowmelt runoff season
(Figure 4). The following lists the range of values measured throughout the
Mainstem watershed during spring water quality monitoring in 2017:
• Water temperature = 0.1º C – 13.6º C
• pH = 6.85 – 8.20
• Specifi c conductivity = 21.4 μS/cm – 109.4 μS/cm
• Turbidity =1.4 NTU – 14.0 NTU
Jorin Botte collects a grab sample
on Joe Wright Creek below
Chambers Lake.
Table 1 - Water quality indicators measured as part of the Upper Cache la Poudre Collaborative Water Quality
Monitoring Program.
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Water Quality Update | Spring 2017
fcgov.com/water-quality
fcgov.com/water-quality
WATER QUALITY INDICATORS CONTINUED
Maximum
Median
Minimum
Graphic Explanation
Data range based on
long-term data record
2008-2016.
Figure 4 – Water quality indicator data collected at key monitoring sites during Spring (April, May, June) 2017.
All water quality indicators at key sites
reported near the long-term median,
indicating normal water quality conditions.
JWC PJW PBR PSF PNF PBD
20
15
10
5
0
TEMP (deg C)
JWC PJW PBR PSF PNF PBD
9
8
7
6
pH
JWC PJW PBR PSF PNF PBD
200
150
100
50
0
CONDUCTIVITY (uS/cm)
JWCPJWPBRPSF PNF PBD
30
20
10
0
TURBIDITY (NTU)
Spring
Median
(2017)
Joe Wright Creek Canyon Mouth
Joe Wright Creek Canyon Mouth
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Water Quality Update | Spring 2017
fcgov.com/water-quality
fcgov.com/water-quality
MICROORGANISMS
Figure 5 – E. coli (a) and (b) T. coli counts on the Poudre
River during the 2017 Spring water quality monitoring.
Through the UCLP Collaborative Monitoring Program,
the Poudre River is routinely tested for the presence of
bacterial contamination by measuring the total amount
of coliforms, an indicator organism for the presence of
pathogenic bacteria.
In addition, Escherichia coli (E. coli) is measured and
used as an indicator of human or animal fecal waste
pollution since the source of origin is more specifi c
than total coliforms. During the spring, snowmelt and
rain serve as delivery mechanisms for E. coli and
total coliforms from the surrounding watershed to the
Poudre River.
Over the Spring 2017 monitoring season, E. coli and
total coliforms were within the range of values seen in
previous years, but slightly higher than the long-term
median (Figure 5a, 5b). E. coli counts ranged from no
detection to 579 cells per milliliter and total coliform
ranged from 57 to 1,633 cells per milliliter.
The highest E. coli count was observed at PNF on
April 10, which was the maximum E. coli count
observed over the eight year monitoring record. Cell
counts were measured nearly two orders of magnitude
lower (5.2 cells per milliliter) on the following event on
April 24 and remained notably lower in subsequent
spring monitoring events in May and June.
E. coli and total coliforms remained
within the range of values seen in
previous years, but were slightly
higher than the long-term median.
PBR PSF PNF PBD
400
300
200
100
0
CELLS/mL
PBR PSF PNF PBD
2000
1500
1000
500
0
CELLS/mL
a) E. coli
b) Total coliforms
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The Upper Cache la Poudre Watershed Collaborative Monitoring Program recently released its 2016
Annual Report, which summarizes the hydrologic and water quality data collected in 2016 and provides
a comparison of water quality from the years 2013-2016. The report also summarizes signifi cant events,
issues of concern, results from special studies, and data quality control. Water quality reports can be
found online at fcgov.com/source-water-monitoring.
Water Quality Update | Spring 2017
fcgov.com/water-quality
2016 UPPER CACHE LA POUDRE WATERSHED ANNUAL REPORT
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0
WATERYEAR
STREAMFLOW(CFS)
Historic Av erage (135 Year Record)
WY2017
Spring WQ sampling
Explanation
b) Cache la Poudre Streamflowat Canyon Mouth
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