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Home My WebLink AboutMemo - Mail Packet - 1/9/2018 - Memorandum From Richard Thorp Re: 2017 Upper Cache La Poudre Watershed - Fall Water Quality UpdateUtilities electric · stormwater · wastewater · water 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: December 15, 2017 TO: Mayor Troxell and Councilmembers FROM: Richard Thorp, Watershed Program Manager THROUGH: Darin Atteberry, City Manager Kevin R. Gertig, Utilities Executive Director RE: 2017 Upper Cache la Poudre Watershed - Fall Water Quality Update 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 Soldier Canyon Water Authority 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 water quality conditions and trends within the Upper CLP watershed. The attached water quality update provides a brief summary of precipitation, streamflow and drought conditions over the 2017 water year, as well as water quality trends during the summer months of October and November. 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. Seasonal reporting 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, https://www.fcgov.com/utilities/img/site _specific/uploads/December_2017_Watershed_Newsletter.pdf. Fall 2017 Highlights Precipitation was above the long-term average during the 2017 water year and remained above average during October and November of the 2018 water year. Fall streamflow near the canyon mouth decreased to baseflow conditions during October and November. All water quality indicators during the 2017 fall monitoring season were within the range of values observed over DocuSign Envelope ID: 582D293F-C291-4A0F-AC64-120181CC873E the long-term monitoring record, indicating normal water quality. The Upper CLP watershed continues to be a reliable, high quality drinking water source. CC: Carol Webb, Water Resources and Treatment Operations Manager, Utilities Jill Oropeza, Water Quality Services Manager, Utilities Jared Heath, Watershed Specialist, Utilities DocuSign Envelope ID: 582D293F-C291-4A0F-AC64-120181CC873E Water Quality Update | Fall 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 2017 Fall Water Quality Update provides a seasonal summary of water quality conditions in the UCLP Watershed by highlighting precipitation and streamﬂ ow conditions, as well as water quality during the fall season (October and November). Routine water quality monitoring 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 diversion structures (Figure 1). More information is available at fcgov.com/source-water-monitoring. Figure 1 - Upper Cache la Poudre Collaborative Monitoring Program sampling locations DocuSign Envelope ID: 582D293F-C291-4A0F-AC64-120181CC873E PRECIPITATION Precipitation was above average by the end of the 2017 water year and start of the 2018 water year (Figure 2a). A snowstorm in early October dropped 18-inches of snow, with an equivalent 2.3 inches of water, in the UCLP Watershed. The fresh snowpack melted over several days and was followed by several smaller mixed precipitation events (rain and snow) through October. Total precipitation monitored at the Joe Wright Snow Telemetry Station near Cameron Pass measured 4.5 inches for the month of October compared to the long-term average of 3.4 inches. Another notable snowstorm in early November delivered 15 inches of snow with an equivalent 2.5 inches of water to the UCLP Watershed. A dryer period followed this storm with cooler temperatures sustaining the snowpack. A slight increase in precipitation was observed through the end of November. Total precipitation in November measured 4.9 inches compared to the long-term average of 4.5 inches. Cumulative precipitation totaled 9.4 inches by December 1, which was 119 percent of average (7.9 inches) (Figure 2b), while the early season snowpack water equivalent measured 71 percent of the long-term median (4.1 inches compared to 4.8 inches). Water Quality Update | Fall 2017 fcgov.com/water-quality WATER YEAR REVIEW Figure 2 – (a) Cumulative precipitation for the 2017 and 2018 water years (WY) and (b) monthly precipitation totals for October and November of 2017 compared to the long-term average. Precipitation data were obtained from the Joe Wright Snow Telemetry station operated by the Natural Resource Conservation Service. Sep Aug Jul Jun May Apr Mar Feb Jan Dec Nov Oct 50 40 30 20 10 0 PRECIPITATION(INCHES) Average (1981 - 2010) WY2017 WY2018 UCLP Cumulative Precipitation Oct Nov 6 5 4 3 2 1 0 PRECIPITATION(INCHES) Average (1981 - 2010) WY2017 WY2018 (Totalsa) Fall Precipitation (b) DocuSign Envelope ID: 582D293F-C291-4A0F-AC64-120181CC873E Water Quality Update | Fall 2017 fcgov.com/water-quality WATER YEAR REVIEW Sep Aug Jul Jun May Apr Mar Feb Jan Dec Nov Oct 3500 3000 2500 2000 1500 1000 500 0 STREAMFLOW(CFS) Average (136 years of record) WY2017 Spring WQ Summer WQ STREAMFLOW Streamﬂ ow in the UCLP Watershed decreased to baseﬂ ow (low ﬂ ow) conditions by early September and ﬂ uctuated around the long-term average through November. Streamﬂ ow ﬂ uctuations through the fall months were driven by a combination of water releases from water storage reservoirs and snowmelt from the early season snow storms. The daily average streamﬂ ow on October 1, 2017 was measured at 125 cubic feet per second (cfs), which was 126 percent of the long-term average (99 cfs). By November 30, streamﬂ ow was measured at 84 cfs, which was slightly higher the historical average of 53 cfs (Figure 3). Figure 3 – Streamﬂ ow measured on the Cache la Poudre River at the Canyon Mouth (CLAFTCCO) during the 2017 water year. This gaging station is operated by the Colorado Division of Water Resources. Cache la Poudre River Streamﬂ ow at Canyon Mouth DocuSign Envelope ID: 582D293F-C291-4A0F-AC64-120181CC873E 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 1). These indicators provide a snapshot of water quality conditions and are useful for indentifying trends or changes in water quality. Signiﬁ cant changes in water quality indicators may provide an early warning of potential water pollution. Water Quality Update | Fall 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, because 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. Conductivity Conductivity is an index of dissolved ionic solids in water. Conductivity is used as a general measure of water quality. Signiﬁ cant increases in conductivity can be used as an indicator of increased pollution. 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. Fall water quality monitoring captures water quality conditions during early baseﬂ ow conditions that begin in early fall and continue through winter. Baseﬂ ow conditions are not inﬂ uenced by direct runoff during the fall and winter seasons, so streamﬂ ow experiences little change which usually results in stable and reliable water quality until snowmelt runoff begins in early April. All water quality indicators during the 2017 fall monitoring season were within the range of values observed over the long-term monitoring record, indicating normal water quality (Figure 4). The median water temperature was near or below the long-term median at all sites. Cooler water temperatures were likely driven by lower than average fall air temperatures. pH was marginally above the long-term median at all sites and slightly increased moving downstream. Conductivity was near the long-term median at monitoring locations higher in the watershed and increased above the long-term average on the Cache la Poudre River below the Town of Rustic. Table 1 - Water quality indicators measured as part of the Upper Cache la Poudre Collaborative Water Quality Monitoring Program. DocuSign Envelope ID: 582D293F-C291-4A0F-AC64-120181CC873E Water Quality Update | Fall 2017 fcgov.com/water-quality 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 Fall (October and November) 2017. Fall Median (2017) Concentrations were similar downstream of the conﬂ uence with the Little South Fork Cache la Poudre River (PSF) suggesting little inﬂ uence from this tributary during the fall season. As expected, turbidity was uniformly low throughout the watershed, indicating that there are likely low levels of suspended solids in the UCLP Watershed. The following lists the range of values measured throughout the Mainstem watershed during summer water quality monitoring in 2017: • Water temperature = 0.13º C – 7.06º C • pH = 7.47 – 8.27 • Speciﬁ c conductivity = 39 μS/cm – 116 μS/cm • Turbidity =0.11 NTU – 1.53 NTU Low turbidity water on the Poudre River on August 14, 2017. Joe Wright Reservoir Canyon Mouth Joe Wright Reservoir Canyon Mouth JWC PJW PBR PSF PNF PBD 24 18 12 6 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) JWC PJW PBR PSF PNF PBD 12 9 6 3 0 NTU DocuSign Envelope ID: 582D293F-C291-4A0F-AC64-120181CC873E Water Quality Update | Fall 2017 fcgov.com/water-quality fcgov.com/water-quality MICROORGANISMS Figure 5 – E. coli (a) and (b) total coliform colony form- ing units (CFUs) in the Poudre River during the 2017 fall season. Coliforms are types of bacteria found naturally in the environment in plant and soil material, but can also be found in the digestive tract of warm-blooded animals, including humans. Disease causing bacteria or pathogens can be introduced to the raw drinking water supply from fecal contamination. Although the water treatment process effectively eliminates pathogens, source watershed monitoring can provide indication of changes in the activity and location of pathogen sources over time. Through the UCLP Collaborative Monitoring Program, the raw Poudre River water supply 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. In fall 2017, E. coli and total coliform counts were within the range of values seen in previous years and below the long-term median (Figures 5a and 5b, respectively). E. coli and total coliform counts were measured on the Poudre below the town of Rustic were higher than the long-term median, but cell counts were still well within the range of values observed over the long-term record. E. coli and total coliforms were within the range of values seen in previous years. PBRPSFPNF PBD 24 18 12 6 0 CELLS/mL PBRPSFPNF PBD 1600 1200 800 400 0 CELLS/mL (a) (b) DocuSign Envelope ID: 582D293F-C291-4A0F-AC64-120181CC873E Water Quality Update | Fall 2017 fcgov.com/water-quality TASTE AND ODOR PBR PNF Monitor Date Geosmin (ng/L) 10/16/2017 11/13/2017 3.16 1.92 1.30 1.92 Geosmin is a naturally occurring organic compound produced by blue green algae, which introduces 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). Geosmin does not pose a public health risk, but it is of concern because its detectable presence can negatively affect customer conﬁ dence in the quality of drinking water. Geosmin is monitored at PBR and PNF during routine UCLP monitoring events. Geosmin concentrations observed at PBR and PNF were below the taste and odor threshold of 4 ng/L in October and November (Table 2). Concentrations were higher on the Poudre River below Rustic (PBR) in October, but were identical at both monitoring sites on the November sampling event. Environmental conditions within the UCLP Watershed, speciﬁ cally cold water temperatures and low nutrients, limit the proliferation of geosmin producing algae; however, there have been episodic occurrences of elevated geosmin throughout the UCLP Watershed, highlighting the importance of routinely monitoring geosmin as an early warning for water treatment operations. Table 2 – Poudre River geosmin concentrations (ng/L) during the fall of 2017 at Poudre above the North Fork (PNF) and Poudre below Rustic (PBR) monitoring locations. PBR PNF DocuSign Envelope ID: 582D293F-C291-4A0F-AC64-120181CC873E