20-Year Groundwater Level Trends (GIS Feature Service)
Groundwater levels at selected wells were analyzed using the Mann-Kendall non-parametric test to determine whether a statistically significant trend (declining trend, no trend, or increasing trends in groundwater levels) was present during the specified time period. To ensure sufficient data quality and temporal coverage, each well included in the analysis must meet minimum data requirements: at least 10 unique years of spring measurements, and those spring measurements must span at least 15 years within the 20-year period. When more than one spring measurement was available for a year, the highest (shallowest) water level was selected to represent that year. If a statistically significant trend was observed, the Theil-Sen method was used to calculate the estimated slope of the trend line to quantify the decline or increase.
These trends are derived from the DWR Periodic Groundwater Levels dataset that contains seasonal and long-term groundwater level measurements collected by the Department of Water Resources and cooperating agencies in groundwater basins statewide. It also includes data collected through the Sustainable Groundwater Management Act (SGMA) Portal’s Monitoring Network Module (MNM), and the CASGEM (California Statewide Groundwater Elevation Monitoring) Program. Most measurements are taken manually twice per year to capture the peak high and low values in groundwater elevations. However, the dataset also includes measurements recorded more frequently, monthly, weekly, or daily. The complete DWR Periodic Groundwater Levels dataset is available at https://data.cnra.ca.gov/dataset/periodic-groundwater-level-measurements
This service is under development as part of ongoing enhancements to CalGW Live.
DWR makes no warranties or guarantees — either expressed or implied — as to the completeness, accuracy, or correctness of the data. DWR neither accepts nor assumes liability arising from or for any incorrect, incomplete, or misleading subject data.
Source: California's Groundwater Live Supporting Data
About this Resource
| Last updated | unknown |
|---|---|
| Created | unknown |
| Name | 20-Year Groundwater Level Trends (GIS Feature Service) |
| Format | Web Resource |
| License | License not specified |
| Created | 10 months ago |
| has views | False |
| id | 643c15cd-3d4c-4c1e-9f19-2ccdea8ed25f |
| metadata modified | 2 months ago |
| package id | f98f112e-cc57-440b-8921-0ad5eff37009 |
| position | 6 |
| state | active |
| tracking summary | {'total': 0, 'recent': 0} |