2019 California Water Quality Status Report

<p>A map layer (shapefile) showing areas in California where that specified contaminant (Nitrate, Arsenic, Total Dissolved Solids, Uranium, 123-TCP, Percholate) is consistently found above the regulatory thresholds to which public water systems are held. The dataset provides the mean, median, minimum, and maximum result values found in that area, as well as the number of wells where it was sampled.</p> <p>This dataset was created for the <a href="https://www.waterboards.ca.gov/resources/data_databases/wq_status_report.html">2019 Water Quality Status Report</a> and 2019 CA State Water Board Data Science Symposium by Groundwater Ambient Monitoring and Assessment Program (GAMA) geologist, Dori Bellan.</p> <p>The full metadata is provided below:</p> <p>The final predicted areas for each of the six chemicals exceeding their relative MCLs in CA groundwater after the final step of professional judgement. These final regions are where these chemicals are typically above their MCLs. Created for CA Water Board Data Science Symposium, July 2019.</p> <p>Empirical Bayesian Kriging (EBK) was used as part of the Geostatistical Analyst extension of ArcGIS Pro v2.1. For each of the six chemicals: nitrate, arsenic, perchlorate, uranium, 1,2,3 Trichloropropane, and total dissolved solids, EBK was used to produce a prediction surface of areas exceeding the relative MCL. EBK used data provided as hosted feature layers within the CA State Water Board GIS Portal; each chemical dataset includes all data (all years), including censored data (translated as detailed below), from the Groundwater Ambient Monitoring and Assessment (GAMA) Program Priority Basin and Domestic Well Projects, and the Division of Drinking Water public supply well datasets. Data points (wells) included must have at least two sampling events, and each well location is assigned the average detection of all sampling results. EBK (to predict the exceedance above the documented MCLs for each chemical) was applied to the statewide datasets for each chemical separately, in one statewide analysis each. Censored data (all detections reported as: equal to zero, less than the most common laboratory method detection limit (MDL), and as "ND") were translated to be the MDL/square root(2). This translation creates the best estimate for a detection, and removes zero values. Since the dataset in each EBK analysis is logarithmically transformed for a more normal distribution and therefore best-fitting model, zero values cannot exist. The final regions produced for nitrate used both the one-half MCL exceedance area and MCL exceedance area predictions.</p> <p>As indicated, a level of professional judgement produced the final regions of predicted exceedances. This is the final feature layer, "Final_All_Chems_Regions" a regional map showing these predicted areas after the step of professional judgement. A summary of these changes is below. If a more detailed explanation is needed, please contact the author indicated in credits.</p> <p>For each of the six chemicals, predicted areas were produced by EBK which only included one or two wells above the MCL. These small areas were not included in the final regions. Also not included are areas predicted by EBK where the model "searched" for an additional well location to continue its prediction. These areas may begin its prediction accurately, but while searching for an additional well "neighbor," the model continues to search and does not find one. This occurs at the boundaries of the state's extent, and was subsequently "clipped" by the state's boundary layer. In a few instances, these areas are finished by wrapping the predicted area around well locations, not extending to the boundary. In areas where this occurs and only a very small number of wells exist in the predicted areas, the predicted area is not included in the final regions. Lastly, final regions may extend slightly to include immediately adjacent wells in exceedance.</p>

<p>The percentage of toxic and non-toxic <em>Hyalella azteca</em> samples collected from 2008 to 2017, based on increasing urban land use (&lt; 25% Urban, &lt;50% Urban, &lt;75% Urban, &lt;100% Urban). The land use category is based on percent urban land use at 5km. As in, how much of the area within 5km of a sampling site is classified as urban. This dataset was created for the 2019 Water Quality Status Report. It was compiled using data from the <a href="https://www.waterboards.ca.gov/water_issues/programs/swamp/spot/">Stream Pollution Trends (SPoT) Monitoring Program</a>, part of the Surface Water Ambient Monitoring Program at the State Water Resources Control Board.</p>

<p>Sum pyrethroid pesticides expressed as toxic units (the potential for a pyrethroid pesticide to cause toxicity). This dataset was created for the 2019 Water Quality Status Report. It was compiled using 2008-2017 data from the <a href="https://www.waterboards.ca.gov/water_issues/programs/swamp/spot/">Stream Pollution Trends (SPoT) Monitoring Program</a>, part of the Surface Water Ambient Monitoring Program at the State Water Resources Control Board.</p>

<p>A map layer (shapefile) of sediment loads in the Elk River watershed by study subbasin. The watershed subbasin boundaries were created in 2005-2007 and were loosely matched with CalWater’s planning watersheds for reference. The sediment loads were derived from the <a href="https://www.waterboards.ca.gov/northcoast/water_issues/programs/tmdls/elk_river/pdf/151222/03_20151021_Upper_Elk_River_Tech_Analysis_for_Sediment.pdf">Upper Elk River: Technical Analysis for Sediment report</a> (pages 59-60, Table 8) published by the North Coast Regional Water Quality Control Board in October 2015. The dataset includes PWS (Public Water System) Name and Average Sediment Load (in cubic yards per square mile per year).</p>

<p>A freshwater harmful algal bloom (FHAB)-related Illness Team was established in 2018 with partners from the State Water Resources Control Board, Office of Environmental Health Hazard Assessment, California Department of Public Health, and Department of Fish and Wildlife. The team investigates FHAB reports that result in a human and animal illness and collect the required data to upload to the US Center for Disease Control’s One Health HABS database. In 2018, the team reported 19 illness cases from 9 counties across the state.</p>

<p>The <a href="https://mywaterquality.ca.gov/monitoring_council/bioaccumulation_oversight_group/index.html">Bioaccummulation Oversight Group (BOG)</a> Bioaccumulation Monitoring Program is implementing a long-term plan to track the status and trends of bioaccumulation in 190 bass lakes throughout California. The 190 lakes have been divided into five subsets (or “panels”), and one panel is sampled every other year. After 10 years all of the panels will have been sampled, and the cycle will begin again so that timely information for each lake is generated once every 10 years. This is a shapefile of all 190 sampling stations as classified by panel group.</p>

<p>Geo-referenced records of Ephemeroptera (mayfly) occurrences in the United States. The dataset includes the geographic coordinates (longitude, latitude), provider name (Global Biodiversity Information Facility [GBIF]), date reported, and month reported. This data is featured as a map in the <a href="http://arcg.is/140HqG">Presence, Patterns, and Predictions: Environmental DNA and Community Science data story</a>.</p> <p><strong>Data source</strong>:<br /> Ephemeroptera in GBIF Secretariat (2017). GBIF Backbone Taxonomy. Checklist dataset <a href="https://doi.org/10.15468/39omei">https://doi.org/10.15468/39omei</a> accessed via GBIF.org on 2019-06-26.</p>

<p>The <a href="https://sccwrp.shinyapps.io/sqi_shiny/">Stream Quality Index (SQI)</a> combines biological, physical, and chemical data to provide an overall picture of stream quality. The SQI assigns stream sites to one of four condition categories: healthy and unstressed, healthy and resilient, impacted by unknown stress, or impacted and stressed. These categories are based on empirical stressor-response models that describe the likelihood of biological alteration with observed chemistry and habitat stressors. All data used to calibrate and validate the tool are from the Southern California Stormwater Monitoring Coalition (SMC) regional watershed monitoring program in coastal southern California, which includes data from the <a href="https://www.waterboards.ca.gov/water_issues/programs/swamp/">Surface Water Ambient Monitoring Program</a>.</p> <p>This is a copy of the file available for download on the <a href="https://sccwrp.shinyapps.io/sqi_shiny/">SQI dashboard</a>. Download the data from the dashboard for the most recent data.</p>