HomeMy WebLinkAboutMemo - Mail Packet - 08/13/2024 - Memorandum from Diana Schmidt re: 2024 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
utilities@fcgov.com
CC: Jill Oropeza, Acting Director of Water Utilities
Leslie Hill, Director of Water Quality Services Division, Utilities
Richard Thorp, Watershed Program Manager, Utilities
Water Commission
MEMORANDUM
Date: August 8th, 2024
To: Mayor Arndt and City Councilmembers
Through: Kelly DiMartino, City Manager
Tyler Marr, Deputy City Manager
From: Diana Schmidt, Watershed Specialist
Subject: 2024 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 and Thornton, Northern Water
Conservancy District and Soldier Canyon Water Treatment Authority. The goal of this
monitoring program is to assist participants with 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 precipitation and drought,
streamflow, and water quality conditions observed in the Upper CLP watershed during spring
2024.
BACKGROUND
Seasonal updates are published annually during spring, summer, and fall each year. These
updates are meant to inform program partners, their customers and other community
stakeholders about the current condition of our source watershed and the quality of the raw
drinking water supply. In-depth water quality trend reporting is accomplished through annual
and five-year technical reports. Water quality reports and seasonal updates are publicly
available on the Fort Collins Utilities’ website, https://www.fcgov.com/utilities/what-we-
do/water/water-quality/source-water-monitoring/upper-poudre-quality-monitoring.
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SPRING 2024 WATER QUALITY UPDATE HIGHLIGHTS
The 2024 spring update summarizes Poudre Watershed conditions during the onset of
snowmelt runoff. The Upper CLP Watershed experienced near average snowpack, precipitation,
and streamflow, and air temperatures were above the historic average. While measurements of
average water temperature, pH, conductivity, and turbidity at several sites were somewhat
elevated, they still were within expected ranges. These elevated values can likely be attributed
to persistent post-fire effects from the Cameron Peak Wildfire that continue to influence Poudre
River water quality during snowmelt runoff. However, water quality conditions are generally
trending toward recovery following the fire.
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Upper Cache la Poudre Watershed Collaborative Monitoring Program
SPRING 2024 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, and Thornton, Soldier Canyon Water
Treatment Authority, and Northern Water. 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 using sites strategically located throughout the watershed. Water quality data
provide valuable information about the health of our source watershed and quality of our raw
water supply.
The Spring 2024 Water Quality Update provides a seasonal summary of watershed conditions in
the Upper CLP watershed by highlighting weather, snowpack, and streamflow conditions over the
spring season (March – May), 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. 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
collected over the period of 2008 to 2012.
Figure 1 – Upper Cache la Poudre
Collaborative Monitoring Program
water quality sampling sites and real-
time water quality instrument locations.
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 near average at the Joe Wright Snowpack Telemetry (SNOTEL) station over the 2024 spring season. Spring
temperatures were 0.4°F warmer than the long-term average and ranked as the 15th warmest spring on record (out of 34 years). The
monthly mean air temperature was near average in March, above average in April, and well below average in May. The month of April
ranked as the 12th warmest on record while May ranked as the 10th coldest on record (Table 1).
Temperature
2024
(ºF)
Average
(ºF)
Departure
(ºF)2024 Rank
March 25.4 25.2 0.2 15th (H)
April 32.9 30.5 2.4 12th (H)
May 37.3 38.5 -1.2 10th (C)
Spring 31.9 31.4 0.4 15th (H)
Precipitation
Precipitation measured at the Joe Wright SNOTEL over the 2024 spring season was near average and ranked as the 16th wettest spring on
record (out of 45 years). Precipitation was above average in March (116%) and April (124%) and below average in May (80%). The month of
April ranked as the 10th wettest on record (Table 2). Abnormally dry and moderate drought conditions were observed near the headwaters
of the Upper CLP watershed during the month of March, and these conditions shifted to the middle and lower portions of the of the
watershed by late May (Figure 2).
Total Precipitation
2024
(inches)
Average
(inches)
% of
Average 2024 Rank
March 5.2 4.5 116%18th (W)
April 7.0 5.7 124%10th (W)
May 3.4 4.3 80%18th (D)
Spring 15.6 14.4 108%16nd (W)
Table 1 – Monthly mean air temperatures
measured at the Joe Wright SNOTEL over
the fall months of 2024 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 2024
fall 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 March 5, 2024, (left) and May 28, 2024
(right). (Map source: https://droughtmonitor.unl.edu/)
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Streamflow Conditions
Streamflow at the Cache la Poudre River near the Canyon Mouth (CLAFTCCO) stream gage measured 66,191 acre-feet of water over the
spring season, which was 97% of the long-term average (calculated over the 1881 – 2023 measurement period). Snowmelt runoff began
as expected in mid-April. Streamflow increased slowly through the end of April and rose more rapidly in May. Streamflow measured above
average in March (110%) and April (119%) and below average in May (93%) (Figure 4).
Figure 4 –
Streamflow
conditions on the
Poudre River over
the 2024 spring
season (left) and
monthly total
water volume
measured over
the spring season
(right).
Snowpack
Snow water equivalent (SWE), the amount of water held in the snowpack, at the Joe Wright SNOTEL station near Cameron Pass was below
normal (median calculated over the 1991 – 2020 measurement period) for the snow accumulation season. Monthly maximum SWE was
below normal between October and May, with the months of October, November, December, and January being well below average. Wet
conditions in the months of February, March, and April contributed to near-baseline SWE in the spring months. The maximum amount of
water contained in the snowpack, referred to as peak SWE, was observed on May 13th and measured 23.6 inches – 99% of normal. Peak
SWE across the entire Upper CLP watershed measured near or above normal. The North Fork and South Fork CLP watersheds measured
slightly above normal (111% and 110%, respectively), while the Mainstem CLP watershed measured near normal (106%) (Figure 3).
Figure 3 – Peak
SWE measured
at snowpack
monitoring sites
throughout the
Upper Cache la
Poudre River
watershed in 2024.
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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.
Spring water quality monitoring captures 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 measured slightly above baseline at nearly all key monitoring sites. Higher water temperatures are likely due to warmer
air temperatures observed across the watershed this spring, particularly during the month of April. pH was slightly elevated at upstream
sites, and below baseline at the City of Greeley’s intake (PBD). A slight increase in baseline pH in the Mainstem CLP has been observed over
the past several years, but the cause is unknown. Specific conductivity was slightly elevated from Joe Wright Creek (JWC) downstream
to the City of Fort Collins’ intake (PNF). Specific conductivity was slightly below the baseline median at City of Greeley’s intakes (PBD).
Turbidity levels 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) (Figure 5).
The elevated specific conductivity and turbidity levels at these sites imply that post-fire impacts from the Cameron Peak Wildfire contin-
ued to influence Poudre River water quality during snowmelt runoff; however, it appears that recent water quality impacts have lessened
compared to previous years.
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Joe Wright Creek Canyon Mouth
Figure 5–
Water quality indicator
data collected at key
monitoring sites over the
2024 spring monitoring
season (April and May)
compared to baseline
spring water quality
conditions.
Spring 2024
Median
Maximum
Median
Minimum
Graphic Explanation
Baseline data
range based
on long-term
data record
2008-2012
2023 Upper Cache la Poudre Watershed Water
Quality Annual Report
The Upper Cache la Poudre Watershed Collaborative Monitoring Program recently released
its 2023 Water Quality Annual Report. The 2023 Annual Report summarizes climate and
hydrology in the Upper CLP watershed over the 2023 calendar year and water quality data
collected as part of the Upper CLP Collaborative Water Quality Monitoring Program. Water
quality reports can be found online at http://www.fcgov.com/source-water-monitoring/.
FCGOV.COM/WATER-QUALITY
Learn More
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