Survey of Reservoir Greenhouse gas Emissions file:///P:/PDF_Harvest/ScienceInventory/ScienceInventoiyHarvest/600. Survey of Reservoir Greenhouse gas Emissions Lake Dalecarlia Water Quality Survey Jake Beaulieu 25 July, 2022 1. Background Between 2020 and 2023 the US Environmental Protection Agency (USEPA) will survey water quality and greenhouse gas (GHG) emissions from 108 reservoirs distributed across the United States (Figure 1). The objective of the research is to estimate the magnitude of GHG emissions from US reservoirs. All reservoirs included in this study were previously sampled by the USEPA during the 2017 National Lakes Assessment (2017 NLA). Data from the 2017 NLA can be found at the EPA website (https://www.epa.gov/national- aquatic-resource-surveys/data-national-aquatic-resource-surveys). Data for Lake Dalecarlia can be found under SITE J D NLA17JN-10171. Afield sensor is used to measure chlorophyll a, dissolved oxygen, pH, specific conductivity, water temperature, and turbidity near the water surface at a minimum of 15 locations within each reservoir. Water samples are collected from the deepest site for analysis of nutrients and chlorophyll a. This preliminary report presents water quality results for Lake Dalecarlia. These data will be included in a formal peer-reviewed publication to be submitted for publication in 2024. Ecoregions Coastal Plains Northern Appalachians Northern Plains Southern Appalachians Southern Plains Temperate Plains Upper Midwest Western Mountains Leaflet (https://leafletjs.com) | Tiles © Esri — Source: Esri, i-cubed, USDA, USGS, AEX, GeoEye, Getmapping, Aerogrid, IGN, IGR UPR-EGP, and the GIS User Community Figure 1, Location of the 108 Reservoirs Included in Study. 2. Lake Dalecarlia Survey Design The Lake Dalecarlia survey design included 15 sampling sites that were sampled on 2020-08-25. Water chemistry samples were collected from a 1,8m deep site nearby the dam (Figure 2). Click on any of the sites to see the site id, water temperature, pH, turbidity, and dissolved oxygen at the water surface. !e Sample sites sensor sites eaflet (https://leafletjs.com) | Tiles © Esri — Source: Esri, i-cubed, USDA, USGS, AEX, GeoEye, Getmapping, Aerogrid, IGN, IGP, UPR-EGP, and the GIS User Community 1 of 5 12/14/2022, 3:23 PM ------- Survey of Reservoir Greenhouse gas Emissions file:///P:/PDF_Harvest/ScienceInventory/ScienceInventoiyHarvest/600. Figure 2. Location of the 15 sampling sites in Lake Dalecarlia. 3. Lake Disturbance and Trophic Status Lakes are often classified according to their trophic state. There are four trophic state categories that reflect nutrient availability and plant growth within a lake. A eutrophic lake has high nutrients and high algal and/or macrophyte plant growth. An oligotrophic lake has low nutrient concentrations and low plant growth. Mesotrophic lakes fall somewhere in between eutrophic and oligotrophic lakes and hypereutrophic lakes have very high nutrients and plant growth. Lake trophic state is typically determined by a wide variety of natural factors that control nutrient supply climate, and basin morphometry. A metric commonly used for defining trophic state is the concentration of chlorophyll a, an indicator of algae abundance, in the water column. Chlorophyll a concentration was 231 ug/L during the sampling, indicating the lake was hypereutrophic. Trophic State Classification Analyte Oligotrophic Mesotrophic Eutrophic Hypereutrophic chlorophyll a (ug/L) <=2 >2 and <=7 >7 and <=30 >30 In addition to classifying lakes by trophic status, lakes can be classified by degree of disturbance relative to undisturbed lakes (i.e. reference lakes) within the ecoregion. Degree of disturbance can be based on a wide variety of metrics, but here we use nutrients (total phosphorus (tp), total nitrogen (tn)), turbidity, chlorophyll a, and dissolved oxygen (do). Lake disturbance values range from least to most disturbed. Turbidity and do were averaged across the top 2m of the water column at the water chemistry site. Nutrient and chlorophyll a samples were collected from a depth of 0.1m. Chemical Condition Indicators Measured at Water Chemistry Site Threshold Values Observed Values parameter units least disturbed moderately disturbed most disturbed concentration status do mg/l >5 >3 < i<5 <3 9 least disturbed turbidity NTU <3.7 >3.7 8 OO CO LO V >5.38 97.98 most disturbed tp ug/l <49 V -P^ CO CM OO V n^i >82 122 most disturbed tn ug/l <1105 LO o A 1<1699 >1699 1732 most disturbed chlorophyll a ug/l <13.9 >13.9 < Si <22.7 >22.7 230.9 most disturbed 4. Within-lake Spatial Patterns 2 of 5 12/14/2022, 3:23 PM ------- Survey of Reservoir Greenhouse gas Emissions file:///P:/PDF_Harvest/ScienceInventory/ScienceInventoiyHarvest/600. A field sensor was used to measure water temperature, pH, dissolved oxygen, and turbidity near the water surface at all sampling sites. Data are reported in figures and tables below. Hover the cursor over any point in the figures to reveal the sitelD corresponding to the adjacent data table. Alternatively, click on any row in the data table to reveal the location of the sampling site on the map. Water temperature, dissolved oxygen, pH, and turbidity were highest in the northern portion of the reservoir, near the 153rd Ave road crossing. Elevated water temperature near the road crossing may have stimulated algal metabolism, resulting in higher dissolved oxygen, pH, and turbidity (e.g. algal biomass contributing to turbidity.) water sitelD temp 1 27.13 2 29.3 3 28.6 4 28.94 5 27.53 6 28.56 7 27.94 8 30.86 10 27.93 11 28.66 12 29.67 23 28.94 24 27.83 25 28.35 sitelD pH 1 9.61 2 9.94 3 9.69 4 9.77 5 9.83 6 9.74 7 9.52 8 10.02 10 9.79 11 9.82 12 9.84 23 9.79 24 9.53 25 9.77 H sitelD Turbidity (NTU) Leaflet (https://ieafletjs.com) | Tiles © Esri — Source: Esri, i-cubed, USDA, USGS, AEX, GeoEye, Getmapping, Aerogrid, IGN, IGP, UPR-EGP, arid the GIS User Community 99.9 Water Temp. I(°C) Leaflet (https://leafletjs.com) | Tiles © Esri — Source: Esri, i-cubed, USDA, USGS, AEX, GeoEye, Getmapping, Aerogrid, IGN, IGP, UPR-EGP, arid the GIS User Community Leaflet (https://leafletjs.com) | Tiles © Esri — Source: Esri, i-cubed, USDA, USGS, AEX, GeoEye, Getmapping, Aerogrid, IGN, IGP, UPR-EGP, and the GIS User Community 3 of 5 12/14/2022, 3:23 PM ------- |