California State Water Resources Control Board

California State Water Resources Control Board

Changes to instream flow are known to be one of the major factors that affect the health of biological communities. Flow alteration can degrade physical habitat and alter water quality, reducing the ability of a stream to support aquatic life. Understanding the relationship between changes in flow and changes in benthic invertebrate communities (a key indicator of stream health) is critical to informing decisions about ecosystem vulnerability, identifying causes of stream and watershed degradation, and setting priorities for future watershed management. Among the range of approaches available for setting flow targets that support biological integrity, a recently completed project in southern California evaluated the Ecological Limits of Hydrologic Alteration (ELOHA) framework to assess the effect of flow alteration on the condition of benthic macroinvertebrate (BMI) communities across the region. The ELOHA framework establishes recommended targets using a process that includes estimation of flow alteration and development of flow-ecology relationships based on the response of biological communities to changes in flow. This project applied to the ELOHA framework to develop regional flow-ecology relationships and targets based on responses in the benthic macroinvertebrate community. The objectives of this project were: 1) Develop a recommended set of flow targets for southern California streams that would maximize the likelihood of maintaining healthy biological communities as indicated by the California Stream Condition Index (CSCI) for benthic invertebrates. 2) Produce a set of tools that can be readily applied to future sites to estimate hydrologic alteration relative to biologically-define targets. This project was led by the **[Southern California Coastal Water Research Project (SCCWRP)](http://www.sccwrp.org/Homepage.aspx)** and developed flow-ecology relationships using data from nearly 600 bioassessment sites sampled over the past eight years. The California Stream Condition Index (CSCI), a measure of biological condition based on benthic macroinvertebrate communities, was calculated at each of these sites (for more information on the CSCI, refer to the **[CSCI Fact Sheet](http://www.waterboards.ca.gov/water_issues/programs/swamp/bioassessment/docs/csci_factsheet.pdf)** and the **[Bioassessment scores map](http://www.waterboards.ca.gov/water_issues/programs/swamp/bioassessment/csci_scores_map.shtml)** that shows statewide CSCI scores and stream hydrologic classifications). The degree of hydrologic alteration at each of these sites was assessed by comparing estimates of present-day and historical flows using a set of regionally calibrated hydrologic models. Differences from historic flow conditions were compared to CSCI scores to estimate the probability of good biological conditions along gradients of increasing hydrologic alteration. The datasets presented here provide the biological and flow metrics calculated for each site to develop recommended flow targets and management priorities at those sites. For more information, please refer the final report for this project, available **[here](http://ftp.sccwrp.org/pub/download/DOCUMENTS/TechnicalReports/974_RecomFlowTargetsForBioIntegrity.pdf)**.

Updated 1 week ago

California State Water Resources Control Board

This data provides results from field analyses, from the [California Environmental Data Exchange Network](https://ceden.waterboards.ca.gov) (CEDEN). The data set contains two provisionally assigned values (“DataQuality” and “DataQualityIndicator”) to help users interpret the data quality metadata provided with the associated result. Due to file size limitations, the data has been split into individual resources by year. The entire dataset can also be downloaded in bulk using the zip files on this page (in csv format or parquet format), and developers can also use the API associated with each year's dataset to access the data. Users who want to manually download more specific subsets of the data can also use the [CEDEN Query Tool](https://ceden.waterboards.ca.gov/CQT/Home/AqtTool), which provides access to the same data presented here, but allows for interactive data filtering.

Updated 2 weeks ago

California State Water Resources Control Board

Wastewater discharges are regulated by the Water Board. Those regulated are generally required to submit Self-Monitoring Reports to the State or Regional Water Board. Some dischargers submit their reports through the electronic Self-Monitoring Report (eSMR) module of the California Integrated Water Quality System (CIWQS). Generally these are for discharges into surface waters regulated by an individual National Pollutant Discharge Elimination System (NPDES) permit, though other dischargers may be included in this dataset as well. This dataset are the monitoring results that have been submitted as data points after the submitters have been approved for electronic submittals (i.e. after the "all electronic date"). Note that this dataset does not include records where the sampling date falls outside of the years shown below. The excluded records include: records where the sampling date is missing, records where the sampling date is invalid (e.g., records with sampling dates in the future or unreasonably far in the past), and records for samples taken prior to year 2006. The excluded records represent approximately 0.1% of all records in the complete eSMR dataset.

Updated 2 weeks ago

California State Water Resources Control Board

Surface water toxicity data from the [California Environmental Data Exchange Network](https://ceden.waterboards.ca.gov) (CEDEN). CEDEN is the California State Water Board's data system for surface water quality in California, and seeks to include all available statewide data (such as that produced by research and volunteer organizations). Data in CEDEN include field, sediment and water column data collected from freshwater, estuarine, and marine environments. Examples of data in CEDEN come from laboratory, physical and biological analyses and include data types associated with chemical, toxicological, field, bio-assessment, invertebrate, fish, and bacteriological assay assessments. The data resource "Surface Water Toxicity" contains two provisionally assigned values (“DataQuality” and “DataQualityIndicator”) to help users interpret the data quality metadata provided with the associated result. Zip files are provided for bulk data downloads (in csv or parquet file format), and developers can use the API associated with the "Surface Water Toxicity" (csv) resource to access the data. Users who want to manually download more specific subsets of the data can also use the [CEDEN Query Tool](https://ceden.waterboards.ca.gov/CQT/Home/AqtTool), which provides access to the same data presented here, but allows for interactive data filtering.

Updated 2 weeks ago

California State Water Resources Control Board

This data provides results from the [California Environmental Data Exchange Network](https://ceden.waterboards.ca.gov) (CEDEN) for field and lab chemistry analyses. The data set contains two provisionally assigned values (“DataQuality” and “DataQualityIndicator”) to help users interpret the data quality metadata provided with the associated result. Due to file size limitations, the data has been split into individual resources by year. The entire dataset can also be downloaded in bulk using the zip files on this page (in csv format or parquet format), and developers can also use the API associated with each year's dataset to access the data. Users who want to manually download more specific subsets of the data can also use the [CEDEN Query Tool](https://ceden.waterboards.ca.gov/CQT/Home/AqtTool), which provides access to the same data presented here, but allows for interactive data filtering. **NOTE:** Some of the field and lab chemistry data that has been submitted to CEDEN since 2020 has not been loaded into the CEDEN database. That data is not included in this dataset, but is available as a supplemental data set available here: [Surface Water - Chemistry Results - CEDEN Augmentation](https://data.ca.gov/dataset/surface-water-chemistry-results-ceden-augmentation) (and is also available via the CEDEN query tool described above). For consistency, many of the conditions applied to the data in this dataset and in the CEDEN query tool are also applied to that supplemental dataset (e.g., no rejected data or replicates are included), but that supplemental data is provisional and may not reflect all of the QA/QC controls applied to the regular CEDEN data available here.

Updated 2 weeks ago