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Home My WebLink AboutMemo - Mail Packet - 12/25/2018 - Memorandum From Jared Heath Re: 2018 Fall Water Quality Update - Upper Cache La Poudre WatershedUtilities 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 17, 2018 TO: Mayor Troxell and Councilmembers FROM: Jared Heath, Watershed Specialist THROUGH: Darin Atteberry, City Manager Jeff Mihelich, Deputy City Manager Kevin R. Gertig, Utilities Executive Director RE: 2018 Fall 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 Soldier Canyon Water Authority partnered in 2008 to implement the Upper CLP Collaborative Water Quality Monitoring Program. The 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 seasonal summary of precipitation, streamflow, air temperature and drought conditions, and water quality during the fall months of September, October and November. Background: The seasonal water quality updates are designed to inform the Upper CLP Collaborative Water Quality 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. Fall 2018 Highlights: The total amount of precipitation that fell in the upper CLP watershed over the 2018 water year (Oct – Sept) ended below average due to a very dry and hot September. September of 2018 ranked as the 3 rd hottest September on record at the Fort Collins weather station. In contrast, air temperature in October and November were closer to expected, and the start of the 2019 water year was the 5 th wettest on record at the Joe Wright Telemetry station near Cameron Pass due to DocuSign Envelope ID: 684897E2-7ACC-4947-94FF-18DE87B7787D well above average precipitation over the months of October and November. Fall streamflow near the canyon mouth was well below average measuring only 55% over the fall season likely due to persisting and expanding drought conditions in the upper CLP watershed. Above average precipitation in October and November lessened drought conditions in the headwaters of the upper CLP watershed. Drought improvement over the coming months will depend on the winter season and snowfall throughout the watershed. Under these conditions, key water quality indicators were within or below the range of values observed over the baseline period of record indicating the upper CLP watershed continued to be a reliable, high quality drinking water source over the fall season. CC: Carol Webb, Water Resources and Treatment Operations Manager, Utilities Jill Oropeza, Water Quality Services Manager, Utilities Richard Thorp, Watershed Program Manager, Utilities DocuSign Envelope ID: 684897E2-7ACC-4947-94FF-18DE87B7787D Water Quality Update | Fall 2018 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 Fall 2018 Water Quality Update provides a seasonal summary of watershed conditions in the upper CLP watershed by highlighting precipitation, streamﬂ ow and drought conditions at the end of 2018 water year (October 1 through September 30) and start of the 2019 water year, as well as water quality during the fall season, as deﬁ ned by the months of September, October, and November. Routine water quality monitoring results are reported for six key monitoring sites located throughout the upper CLP watershed, which capture water quality conditions above and below major tributaries and near water supply intake structures (Figure 1). Water quality measured over the 2018 fall season is compared to baseline water quality data collected over the period of 2008 to 2012. Figure 1 - Upper Cache la Poudre Collaborative Monitoring Program sampling locations DocuSign Envelope ID: 684897E2-7ACC-4947-94FF-18DE87B7787D PRECIPITATION The 2018 water year ended with very little precipitation in the upper CLP watershed. Only two tenths of an inch of precipitation was measured in September resulting in below average total precipitation to end the 2018 water year. Despite the below average precipitation observed in September (7% of average), precipitation measured over the 2018 fall season was above average. Several storm systems from early to mid-October delivered over 4-inches of mixed precipitation (rain and snow) to the upper CLP watershed. Drier conditions were observed through the remainder of October, but the total monthly precipitation for October was well above average and measured 5.0 inches – 135% of average (Figure 2). Winter storms delivered several inches of snow to the upper CLP watershed through November. Over two feet of snow accumulated at the Joe Wright Snow Telemetry (SNOTEL) station by the end of November. The total monthly precipitation for November measured 6.5 inches – 148% of average. The start of the 2019 water year was the ﬁ fth wettest on record with a total of 11.5 inches of precipitation recorded at the Joe Wright SNOTEL from October through November. The amount of snow contained with the early season snowpack (snow water equivalent) was 108% of normal on December 1. Water Quality Update | Fall 2018 fcgov.com/water-quality Figure 2 – Total monthly precipitation measured at the Joe Wright Snow Telemetry station near Cameron Pass over the fall season. Precipitation data were obtained from the Natural Resource Conservation Service. SeptemberOctober November 6 4 2 0 PRECIPITATION (IN) Average (1981-2010) 2018 DocuSign Envelope ID: 684897E2-7ACC-4947-94FF-18DE87B7787D Period of Record Averages Extremes (125 year record) Max (°F) Min (°F) Mean (°F) Highest Mean (°F) Year 2018 Rank September 1893 - 2012 75.4 45.1 60.3 67.1 2015 3rd 2018 81.3 49.8 65.6 October 1893 - 2012 64.2 34.2 49.2 56.2 2016 74th 2018 62.3 35.9 49.1 November 1893 - 2012 51.1 23.1 37.1 45.8 1949 46th 2018 51.0 26.0 38.5 Fall 1893 - 2012 63.6 34.1 48.9 55.4 2016 18th 2018 65.7 37.3 51.2 Water Quality Update | Fall 2018 fcgov.com/water-quality TEMPERATURE Air temperature measured at the Fort Collins weather station measured over the 2018 fall season was 2.3°F warmer than the long-term average (1893-2012). The month of September was particularly hot and ranked as the 3rd hottest September on record. The monthly mean temperature in September was 5.3°F warmer than the long-term average. Temperatures in October and November were near average; however, the average minimum air temperature was slightly warmer than the long-term average (Table 1). Table 1 – Average maximum, minimum and mean air temperatures measured at the Fort Collins weather station over the fall months of 2018 compared to the long-term averages (1893-2012). Data were obtained from the National Climatic Data Center. STREAMFLOW The total volume of water that ﬂ owed past the canyon mouth of the Poudre River over the 2018 water year measured 211,716 acre-feet – 80% of average. Fall streamﬂ ow was well below average in all months. The total amount of water measured over the fall season at the canyon mouth was 55% of average (Figure 3). Figure 3 – Daily average streamﬂ ow (left) and monthly streamﬂ ow (right) measured over the fall season on the Poudre River near the canyon mouth. Data were obtained from the Colorado Division of Water Resources. Sep Oct Nov 250 200 150 100 50 STREAMFLOW (CFS) Av erage (137 year record) 2018 Fall Sampling SeptemberOctoberNovember 10000 7500 5000 2500 0 STREAMFLOW (acre-feet) Historic Average (137 year record) 2018 DocuSign Envelope ID: 684897E2-7ACC-4947-94FF-18DE87B7787D Water Quality Update | Fall 2018 fcgov.com/water-quality DROUGHT Dry conditions over the summer and early fall (September) resulted in an expansion of abnormally dry conditions throughout much of the upper CLP watershed and moderate drought conditions to the headwaters of upper CLP watershed. Above average precipitation in October and November lessened drought conditions in the headwaters to abnormally dry at the end of November (Figure 4). Over the next several months, drought conditions will be dependent on winter storm systems delivering snow to upper CLP watershed. Figure 4 - Drought conditions throughout Colorado measured by the U.S. Drought Monitor on November 27, 2018 (Note: Larimer County is outlined in red circle). DocuSign Envelope ID: 684897E2-7ACC-4947-94FF-18DE87B7787D The Upper Cache la Poudre Collaborative Water Quality Monitoring Program tests for several key water quality indicators, including pH, conductivity, temperature, and turbidity (Table 2). 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 early warning for potential water pollution. Water Quality Update | Fall 2018 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 monitoring captures water quality as streamﬂ ow on the Poudre River transitions to baseﬂ ow (or low ﬂ ow) conditions. During this time of the year water quality is generally stable throughout the watershed. Water releases from high elevation water storage reservoirs and storm events may cause changes in streamﬂ ow and water quality through September and early October, although these events are temporary. Substantial water releases in the upper CLP watershed typically cease (depending on demand) in October, and storm events this time of year are uncommon, as precipitation in the upper CLP shifts from rain to snow. Most water quality constituents begin to concentrate under baseﬂ ow conditions and water temperature decreases, especially in the higher elevations of the watershed. Over the fall months of 2018, water quality indicators measured at key sites along the Poudre River were within or below the range of values observed over the baseline period of record (Figure 5). Water temperature and turbidity were lower than normal at all key sites. pH and speciﬁ c conductivity were lower than normal at higher elevation monitoring sites, JWC and PJW, and slightly above normal from Rustic downstream to water supply intakes at PNF and PBD. The following lists the range of values measured throughout the Mainstem watershed during fall water quality monitoring in 2018: Table 2 – Water quality indicators measured as part of the Upper Cache la Poudre Collaborative Water Quality Monitoring Program. DocuSign Envelope ID: 684897E2-7ACC-4947-94FF-18DE87B7787D Water Quality Update | Fall 2018 fcgov.com/water-quality Maximum Median Minimum Graphic Explanation Data range based on long-term data record 2008-2012. Figure 5 – Water quality indicator data collected at key monitoring sites over the 2018 fall monitoring season (September, October, November) compared to baseline fall water quality conditions (2008-2012). Fall Median (2018) JWC PJW PBR PSF PNF PBD 20 15 10 5 0 DEGREES CELSIUS JWC PJW PBR PSF PNF PBD 9 8 7 pH JWC PJW PBR PSF PNF PBD 150 125 100 75 50 CONDUCTIVITY (uS/cm) JWC PJW PBR PSF PNF PBD 3 2 1 0 TURBIDITY (NTU) Joe Wright Creek Canyon Mouth Joe Wright Creek Canyon Mouth The following lists the range of values measured throughout the Mainstem watershed during fall water quality monitoring in 2018: • Water temperature = 0.0oC – 18.9oC • pH = 6.86 – 8.60 • Speciﬁ c conductivity = 40.2 μS/cm – 100.8 μS/cm • Turbidity = 0.04 NTU – 1.07 NTU WATER QUALITY INDICATORS CONTINUED DocuSign Envelope ID: 684897E2-7ACC-4947-94FF-18DE87B7787D Water Quality Update | Fall 2018 fcgov.com/water-quality TASTE AND ODOR COMPOUNDS Geosmin and 2-Methylisoborneol (2-MIB) are naturally occurring organic compounds that are produced by some species of blue-green algae. These compounds can introduce an earthy odor to drinking 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 they can negatively affect customer conﬁ dence in the quality of drinking water. Early detection of elevated concentrations of these compounds is important so that they can be removed during the water treatment process. Geosmin and 2-MIB are monitored at PBR and PNF during routine upper CLP water quality monitoring events. Geosmin was detected above the report limit (2 ng/L) at PNF and PBR in October and at PBR in November (Table 3). 2-MIB was detected above the reporting limit (5 ng/L) at PBR in September and at PBR and PNF in October. Routine monitoring of geosmin and 2-MIB in ﬁ nished water samples at the Fort Collins Water Treatment Facility conﬁ rmed that these compounds were successfully removed during the treatment process. Table 3 – Poudre River geosmin and 2-MIB concentrations (ng/L or ppt) during the fall of 2018 at Poudre above the North Fork (PNF) and Poudre below Rustic (PBR) monitoring locations. Note: Reporting limits are 2 ng/L for geosmin and 5 ng/L for MIB. Concentrations below the reporting limits are estimates. Concentrations above the reporting limit are highlighted in red. Monitor Date 9/10/2018 10/15/2018 1.99 5.97 9.97 10.73 PBR PNF Geosmin (ng/L) 2 MIB (ng/L) Geosmin (ng/L) 2 MIB (ng/L) 1.38 4.62 8.81 2.58 11/12/2018 2.22 0.00 0.00 2.53 DocuSign Envelope ID: 684897E2-7ACC-4947-94FF-18DE87B7787D