HomeMy WebLinkAboutMemo - Mail Packet - 7/21/2020 - Memorandum From Jared Heath Re: 2020 Spring Water Quality Update - Upper Cache La Poudre WatershedUtilities
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PO Box 580
Fort Collins, CO 80522
970.212.2900
V/TDD: Dial 711 for Relay Colorado
utilities@fcgov.com
fcgov.com/utilities
M E M O R A N D U M
DATE: July 14, 2020
TO: Mayor Troxell and Councilmembers
FROM: Jared Heath, Watershed Specialist
THROUGH: Darin Atteberry, City Manager
Theresa Connor, Interim Utilities Executive Director
RE: 2020 Spring Water Quality Update – Upper Cache la Poudre Watershed
Bottom Line:
In the shared interest of monitoring the Upper Cache la Poudre (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 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 summary of temperature, snowpack,
streamflow, and water quality conditions monitored in the Upper CLP watershed during the
spring months of April and May in 2020.
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 2020 Highlights:
The Upper CLP watershed continues to be a reliable, high quality drinking water source for the
City of Fort Collins. Snowpack conditions were slightly above normal by the end of the 2020
snow accumulation season. Peak snow water equivalent measuring 116 percent of normal for
the CLP watershed. Over the spring season, dry and warm conditions were observed with below
average precipitation and warmer than average air temperatures measured from March through
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April. Despite these conditions, all water quality indicators at key sites along the Upper CLP
River measured within the range of baseline conditions indicating normal water quality
conditions on the Poudre River during the spring 2020 snowmelt runoff season.
CC: Carol Webb, Utilities Deputy Director - Water Resources and Treatment Operations
Jill Oropeza, Water Quality Services Director, Utilities
Richard Thorp, Watershed Program Manager, Utilities
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fcgov.com/water-quality
SOURCE WATER MONITORING
JWC - Joe Wright Creek above the confluence with the Poudre River
PJW - Poudre River above the confluence with Joe Wright Creek
PBR - Poudre River below the Town of Rustic
PSF - Poudre River below the confluence with the Little South Fork
PNF - Poudre River above the confluence with the North Fork at the
City of Fort Collins’ Intake
PBD - Poudre River below the confluence 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 2020 Water Quality Update
provides a seasonal summary of watershed
conditions in the UCLP watershed by
highlighting snowpack and streamflow
conditions, as well as water quality information
collected over the months of April and May.
Water quality during spring snowmelt runoff is
highly variable. To better capture this seasonal
variability, monitoring is conducted two times
per month from April through June. In 2020,
the UCLP monitoring plan was adjusted to meet
resource constraints because of the COVID-19
pandemic. For the Spring 2020 Water Quality
Update, results are only reported for the two
key monitoring sites located near the City of Fort
Collins’ (PNF) and City of Greeley’s (PBD) water
supply intake structures (Figure 1). Present
water quality conditions at these sites are
compared to baseline water quality conditions
collected over the period of 2008 to 2012.
Figure 1 - Upper Cache la Poudre Collaborative Monitoring Program
sampling locations
Water Quality Update | Spring 2020 Monitoring and Protecting Our Water Sources
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TEMPERATURE
Air temperature measured at the Joe Wright SNOTEL over the 2020 spring season was 3.1°F warmer than the long-
term average and ranked as the fourth warmest spring on record. The monthly mean air temperatures for March,
April and May were all above the long-term average. The months of March and May were particularly warm and
ranked as the fifth and second warmest on record (Table 1).
Water Quality Update | Spring 2020
fcgov.com/water-quality
Table 1 – Monthly mean air temperatures measured at Joe Wright SNOTEL over the spring months of 2020 compared to
the long-term average (1990 – 2019).
PRECIPITATION
Precipitation measured at the Joe Wright SNOTEL over the 2020 spring season was 80% of the long-term average
and ranked as the ninth driest spring on record. All spring months measured below average. The largest deficit in
the monthly total precipitation was observed in the month of May, which measured 72% of average (Table 2).
Table 2 – Monthly accumulated
precipitation totals measured at the Joe
Wright SNOTEL over the 2020 spring
season compared to the long-term
average (1981–2010).
Note: W = wettest and D = driest
Period of
Record
Temperature
2020 (ºF) Average (ºF) Departure (ºF) 2020 Rank
March 29.0 25.0 4.0 5th (H)
April 32.0 30.5 1.5 12th (H)
May 42.0 38.3 3.7 2nd (H)
Spring 34.3 31.3 3.1 4th (H)
Period of Record
Total Precipitation
2020
(inches)
Average
(inches) % average 2020 Rank
March 3.8 4.7 80% 12th (D)
April 4.5 5.2 87% 16th (D)
May 3.2 4.5 72% 14th (D)
Spring 11.5 14.4 80% 9th (D)
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Water Quality Update | Spring 2020
fcgov.com/water-quality
SNOWPACK
Snow water equivalent (SWE), the amount of water held in the snowpack, was above normal at snow telemetry
stations (SNOTEL) throughout the Upper CLP watershed. The Joe Wright SNOTEL near Cameron Pass was below
the long-term (1981–2010 median (normal)) for most of the snow accumulation season. A series of potent winter
storms from late-January through early-February delivered 4-6 feet of snow to the mountains in the Upper CLP
watershed. SWE measured above normal following this storm cycle and remained above normal through the
remainder of the snow accumulation season. The maximum amount of water contained in the snowpack, referred
to as peak SWE, was observed on April 28 at the Joe Wright SNOTEL and measured at 25.3 inches – 108% of
normal (Figure 2).
Figure 2 – Peak snow water equivalent measured at SNOTEL sites throughout the Upper Cache la Poudre River
watershed in 2020.
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Water Quality Update | Spring 2020
fcgov.com/water-quality
Figure 3 – Streamflow conditions on the Poudre River over the 2020 spring season (left) and monthly total
water volume measured over the spring season (right).
STREAMFLOW CONDITIONS
Streamflow at the Cache la Poudre River near the Canyon Mouth (CLAFTCCO) stream gage measured 62,785 acre-
feet over the spring season, which was slightly below the long-term average (93%). Streamflow was near average in
March (103%) and below average in April (80%) and May (93%) (Figure 3). There was a slight delay in the start of
snowmelt runoff in 2020, but streamflow rapidly began to rise in early May. Cooler weather in late-May briefly slowed
snowmelt runoff but hot weather followed, and streamflow quickly increased above the long-term average. In 2020,
peak streamflow was measured on June 1 at 3,020 cubic feet per second (cfs). Peak streamflow occurred 10 days
earlier than average and measured approximately 150% of the long-term average peak streamflow.
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The Upper Cache la Poudre Collaborative Water Quality Monitoring Program uses several key water quality
indicators, including pH, conductivity, temperature and turbidity, which act as surrogates for other parameters.
(Table 2). These indicators provide a snapshot of water quality conditions and are useful for identifying trends or
changes in water quality. Significant changes in water quality indicators may provide an early warning of potential
water pollution.
Water Quality Update | Spring 2020
fcgov.com/water-quality
WATER QUALITY INDICATORS
Table 2 – Water quality indicators measured as part of the Upper Cache la Poudre Collaborative Water Quality
Monitoring Program.
Water Quality Indicator Explanation
Temperature
Water temperature influences 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 compounds, geosmin and 2-methlyisoborneol.
pH
pH is an important water quality parameter to monitor, because it
influences 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.
Specific Conductivity
Conductivity is an index of dissolved ionic solids in water.
Conductivity is used as a general measure of water quality.
Significant increases in conductivity can be used as an indicator
of increased pollution.
Turbidity
Turbidity is monitored to track changes in water clarity. Clarity is
influenced 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.
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Water Quality Update | Spring 2020
fcgov.com/water-quality
Figure 4 – Water quality indicator data collected at key monitoring sites over the 2020 spring monitoring season
(April and May) compared to baseline spring water quality conditions.
Spring water quality monitoring captures water quality conditions from the start of snowmelt runoff to peak streamflow.
Water quality conditions vary with changes in elevation and contributing watershed area. Water quality indicators on
the Mainstem CLP River near the City of Fort Collins’ (PNF) and City of Greeley’s (PBD) water supply intakes measured
within the range of baseline conditions, indicating normal water quality conditions on the Poudre River during the
spring 2020 snowmelt runoff season (Figure 4). Water temperature was slightly higher than baseline. pH and specific
conductivity were near baseline on the Mainstem CLP River near the City of Fort Collins’ water supply intake (PNF) and
higher than the baseline on the Mainstem CLP River near the City of Greeley’s intake (PBD). Turbidity was higher than
baseline at both monitoring locations.
WATER QUALITY INDICATORS CONTINUED
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Water Quality Update | Spring 2020
fcgov.com/water-quality
TASTE AND ODOR COMPOUNDS
Geosmin and 2-Methylisoborneol (MIB) are naturally occurring organic compounds that introduce an earthy odor to
water that can be detected by the most sensitive individuals at concentrations as low as 4 nanograms per liter (ng/L)
or 4 parts per trillion (ppt). These compounds do not pose a public health risk but are of concern because their
detectable presence can negatively affect customer confidence in the quality of drinking water. Geosmin and 2-MIB
are monitored at PBR and PNF during routine UCLP monitoring events.
Geosmin was detected at the City of Fort Collins’ water supply intake (PNF) on May 26, but was only slightly above
the water quality laboratory’s reporting limit of 2 ng/L. 2-MIB was not detected above the water quality laboratory’s
reporting limit (5 ng/L).
Casey Barby, Watershed Technician, collects
water quality indicator data on the North Fork
Cache la Poudre River in early spring using a
multi-parameter water quality sonde.
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Water Quality Update | Spring 2020
fcgov.com/water-quality
2019 UPPER CACHE LA POUDRE WATERSHED
WATER QUALITY REPORT
The Upper Cache la Poudre Watershed Collaborative
Monitoring Program recently released its 2019 Annual
Report. It summarizes climate and hydrology in the
Upper CLP watershed in 2019 and water quality data
collected as part of the Upper CLP Collaborative Water
Quality Monitoring Program. Water quality reports can
be found online at fcgov.com/source-water-monitoring/.
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