HomeMy WebLinkAboutMemo - Mail Packet - 8/8/2023 - Memorandum From Jared Heath Re: 2023 Spring Water Quality Update – Upper Cache La Poudre Watershed
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700 Wood Street
PO Box 580
Fort Collins, CO 80522
970.221.6700
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utilities@fcgov.com
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M E M O R A N D U M
DATE: July 11, 2023
TO: Mayor Arndt and Councilmembers
FROM: Jared Heath, Watershed Specialist
THROUGH: Tyler Marr, Deputy City Manager
Jason Graham, Director of Water Utilities
RE: 2023 Spring Water Quality Update – Upper Cache la Poudre Watershed
Bottom Line:
The Upper Cache la Poudre (CLP) Watershed Collaborative Water Quality Monitoring Program
is a partnership between the cities of Fort Collins, Greeley, Thornton, and Soldier Canyon
Drinking Water Authority. The goal of this shared 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 2023 spring season.
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 CLP River 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. Water quality reports and seasonal updates are made publicly
available on the Fort Collins Utilities website, fcgov.com /source-water-monitoring.
Spring 2023 Highlights:
Spring water quality monitoring captures water quality conditions from the start of snowmelt
runoff to near-peak streamflow in the CLP River. Water quality conditions vary with changes in
elevation, hydrologic and weather conditions, and other potential watershed impacts.
Snowpack conditions in the Upper CLP watershed were above normal for most of the snow
accumulation season. The maximum amount of water stored within the snowpack measured 118
percent of normal. Air temperature measured cooler than average, and precipitation measured
below average with a general drying trend from March through May. No drought conditions
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were observed in the Upper CLP watershed over the spring 2023 season. Streamflow in the
Poudre River near the canyon mouth measured 110 percent of average over the spring season.
As expected, water quality conditions were variable over the spring 2023 monitoring season.
Key water quality indicators were measured within the expected spring water quality conditions
(baseline). Water clarity (turbidity) was slightly elevated due to continued impacts from the
Cameron Peak Fire; however, it appears that recent water quality impacts from the fire have
lessened compared to previous years. The Upper CLP Collaborative Water Quality Monitoring
Program recently released its 2022 Water Quality Trend Report. The report provides a more in-
depth analysis of recent impacts on water quality from the Cameron Peak Fire, as well as long-
term trends in hydrology, climate, and water quality of the Upper CLP watershed over the last 15
years.
CC: Kelly DiMartino, City Manager
Kendall Minor, Utilities Executive Director
Jill Oropeza, Senior Director of Water Sciences & Planning, Utilities
Richard Thorp, Watershed Program Manager, Utilities
Water Commission
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Upper Cache la Poudre Watershed Collaborative Monitoring Program
SPRING 2023 WATER QUALITY UPDATE
Source Water Monitoring
The Upper Cache la Poudre (CLP) Watershed Collaborative Water Quality Monitoring
Program is a partnership between the cities of Fort Collins, Greeley, Thornton, and Soldier
Canyon Water Treatment Authority. The goal of the program is to help these water providers
meet present and future drinking water treatment goals.
Water quality monitoring of our raw, CLP River drinking water supply is conducted from
April through November. Monitoring sites are strategically located throughout the Upper CLP
watershed. Water quality data provide valuable information about the health of our source
watershed and the quality of our raw water supply.
The Spring 2023 Water Quality Update provides a seasonal summary of watershed
conditions in the Upper CLP watershed by highlighting weather, drought, streamflow, and
water quality conditions over the spring season (March – May).
Water quality during spring snowmelt runoff is highly variable. To better capture this
seasonal variability, monitoring is conducted two times per month. Results are reported
for six key monitoring sites located throughout the Upper CLP watershed. Monitoring sites
capture water quality conditions above and below major tributaries and near water supply
intake structures (Figure 1). Current water quality conditions are compared to baseline water
quality conditions over the period of 2008 to 2012.
Figure 1 – Upper Cache la Poudre
Collaborative Monitoring Program
water quality sampling sites (key
sites) and real-time water quality
instrument locations (water quality
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 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.
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Temperature
Air temperature measured at the Joe Wright Snowpack Telemetry (SNOTEL) station over the 2023 spring season was 1.2°F cooler than the
long-term average and ranked as the 10th coldest spring on record (out of 34 years). The monthly mean air temperature was well below
average in March, near average in April, and above average in May. The month of March ranked as the coldest on record, while the month of
May ranked as the 7th warmest on record (Table 1).
Temperature
2023
(ºF)
Average
(ºF)
Departure
(ºF)2023 Rank
March 19.9 25.2 -5.3 1st (C)
April 30.0 30.5 -0.5 11th (C)
May 40.8 38.5 2.3 7th (H)
Spring 30.2 31.4 -1.2 10th (C)
Precipitation
Precipitation measured at the Joe Wright SNOTEL over the 2023 spring season was below average and ranked as the 12th driest spring on
record (out of 45 years). Precipitation was above average in March (122%) and below average in April (80%) and May (54%). The month
of May ranked as the fifth driest on record (Table 2). Drought was not observed near the headwaters of the Upper CLP watershed over the
spring 2023 season (Figure 2).
Total Precipitation
2023
(inches)
Average
(inches)
% of
Average 2023 Rank
March 5.5 4.5 122%11th (W)
April 4.5 5.7 80%17th (D)
May 2.3 4.3 54%5th (D)
Spring 12.3 14.4 85%12th (D)
Table 1 – Monthly mean air temperatures measured at Joe
Wright SNOTEL over the spring months of 2023 compared to
the long-term average (1991 – 2020).
Note: H = hottest and C = coldest
Table 2 – Monthly accumulated precipitation totals measured
at the Joe Wright SNOTEL over the 2023 spring season
compared to the long-term average (1991 – 2020).
Note: W = wettest and D = driest
Figure 2 – Drought conditions for the state of Colorado as monitored by the United States Drought Monitor on Mar. 7, 2023 (left) and May 30, 2023
(right). Map source: droughtmonitor.unl.edu
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Streamflow Conditions
Streamflow at the Cache la Poudre River near the Canyon Mouth (CLAFTCCO) stream gage measured 75,049 acre-feet of water over
the spring season, which was 110% of the long-term average (calculated over the 1881 – 2022 measurement period). Snowmelt runoff
began as expected in mid-April. Streamflow increased slowly through the end of April and began to rise more rapidly in May. Streamflow
measured near average (96%) in March, below average (80%) in April, and above average (116%) in May (Figure 3).
Figure 3 –
Streamflow
conditions on the
Poudre River over
the 2023 spring
season (left) and
monthly total
water volume
measured over
the spring season
(right).
Water Quality Indicators
The Upper CLP 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 3). These indicators provide a snapshot of water quality
conditions and are useful for identifying trends or changes in water quality. Significant changes in these water quality indicators may
provide an early warning of potential water pollution.
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.
Table 3 – Water quality
indicators measured as
part of the Upper Cache
la Poudre Collaborative
Water Quality Monitoring
Program.
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Joe Wright Creek Canyon Mouth
Spring water quality monitoring captures water quality conditions from the
start of snowmelt runoff to near-peak streamflow in the CLP River. Water
quality conditions vary with changes in elevation, contributing watershed
area and potential watershed impacts.
Water temperature and pH were measured near baseline at all key
monitoring sites. Specific conductivity, the ability of water to conduct
electrical current, was measured near the baseline maximum from Joe
Wright Creek (JWC) downstream to the Mainstem below the South Fork
(PSF). Specific conductivity was near the baseline median at the City of Fort
Collins intake (PNF) and below the baseline median at the City of Greeley’s
intake (PBD). Turbidity levels, how clear or cloudy water appears, were
measured near the baseline median at higher elevation monitoring sites in
Joe Wright Creek (JWC) and the Mainstem above Joe Wright Creek (PJW). A
notable increase in turbidity was observed in the Poudre below Rustic (PBR)
downstream to the City of Greeley’s intake (PBD). Turbidity levels at these
sites were near the baseline maximum but remained within the baseline
range of values (Figure 5).
The elevated specific conductivity and turbidity levels at these sites imply
that post-fire impacts from the Cameron Peak Wildfire continued to influence
Poudre River water quality during snowmelt runoff; however, it appears that
recent water quality impacts have lessened compared to previous years.
Figure 4– Water quality
indicator data collected
at key monitoring
sites over the 2023
spring monitoring
season (April and
May) compared to
baseline (2008 - 2012)
spring water quality
conditions.
Spring
2023
Median
Maximum
Median
Minimum
Graphic Explanation
Baseline data
range based
on long-term
data record
2008-2012
Jim Fahey, Watershed Technician with the City of Fort Collins, collects
water samples from the Poudre River near the City’s raw water intake
location.
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Snowpack
Snow water equivalent (SWE), the amount of water
held in the snowpack, at the Joe Wright SNOTEL
station near Cameron Pass was well above normal
(median calculated over the 1991 – 2020 measurement
period) for most of the snow accumulation season
(October through May). The monthly maximum SWE
was well below normal in October and November
and above normal from December through May.
The maximum amount of water contained in the
snowpack, referred to as peak SWE, was observed on
May 1st and measured 28.2 inches, or 118% of normal.
Peak SWE across the entire Upper CLP watershed
measured near normal to above normal. The Poudre
Mainstem and North Fork CLP watersheds measured
above normal (117% and 115%, respectively), while the
South Fork CLP watershed measured slightly below
normal (95%) (Figure 5).
FCGOV.COM/WATER-QUALITY
Learn More
2022 Upper Cache la Poudre Watershed Water
Quality Trend Report
The Upper Cache la Poudre Watershed Collaborative Monitoring Program recently released its 2022
Water Quality Trends Report. The five-year water quality trend report analyzes the hydrology, climate,
and water quality of the Upper CLP watershed over the last 15 years. Water quality data collected
throughout the Upper CLP watershed were analyzed for short and long-term trends to determine if
concentrations increased, decreased, or stayed the same over the five-year period of record from 2018
to 2022 and the long-term period of record from 2008 to 2022, respectively. The report documents 1)
watershed impacts and issues of concern; 2) significant trends in climate, hydrology, and water quality
in the Upper CLP watershed; 3) potential sources of pollution and/or watershed disturbances
influencing water quality trends; and 4) a summary of significant findings and implications to water
treatment.
Water quality reports can be found online at fcgov.com/source-water-monitoring/.
Figure 5 – Peak SWE measured at snowpack
monitoring sites throughout the Upper Cache la
Poudre River watershed in 2023.
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