GIS layer

Overview¶

Our GIS (Geographic Information System) layer is accessible by clicking “Explore” button located at the top left corner of the fastpath app. Once you click the button, you will see the webpage looks like Figure 1. This is the page where you can explore available datasets, and select the data they want to work with in the application. There are four red boxes highlighting compositions of the GIS layer.

Explanation about each box is provided below:

• #1: Simulation panel
  • If you wants to use the data in our online database (referred to as public data in the app):
    • Green box in the panel allows you to draw a polygon for defining a region of interest.
    • Once the polygon is drawn (i.e., closed), then the app will automatically query the database to obtain statistics about the available data within the region of interest.
    • An example polygon and corresponding results of the data query are shown in Figure 2.
  • If a user wants to use your own data (referred to as my data in the app), then you can select one of “my data sets”.

• #2: Green box - this also allows user to draw a polygon. That is, there are two entry points for drawing a user defined polygon.

• #3: Base maps - different base maps can be chosen as shown Figure 3.

  

• #4: Other available maps - list of maps are shown in Figure 4.

  

Depending upon your choice of using public data available from our database or your own data (i.e., “my data” in the app), your interactions with our app will be different.

Use data in our online database (“public data” in the app)¶

If you are using the public data available in our database, you first need to define your region of interest either drawing a polygon or selecting a provided polygon. We have already explained how you can draw a polygon, so we will explain how you can select a provided polygon. By clicking #4 in [[fig, you will see Figure 4. Then you can check an option: “Groundwater Basins”. Once you checked that option, boundaries of the Groundwater Subbasins will show up on the map as shown in Figure 5.

If you hover your cursor over a subbasin and click then you will see a pop-up window as shown in Figure 6. Clicking a button, “Set Selection”, will start querying the database to find available data within the boundary of the selected subbasin (i.e., region of interest).

Figure 7 shows example results of the query displayed in the GIS layer. Let’s explore the data showed in the Simulation panel located on the left side.

Once a region of interest has been selected, the simulation panel will expand and include six parts as shown in Figure 7:

• Start by finding public data sets
  • To set a new region of interest, click the trashcan to clear the current region selection.
• EM Surveys Available: show available EM surveys intersecting the region of interest. Select the dataset you would like to proceed with (only one EM dataset can be used at a time).
  • Types of EM surveys
    • AEM (airborne EM) survey
    • tTEM (towed time-domaine EM) survey
  • Source of EM surveys
    • cdwr (California Department of Water Resources)
    • senvgp (Stanford Environmental Geophysical Research Group)
• Sediment/Rock Type Data: show available number of wells containing sediment/rock type data within the region of interest.
  • Options [user can choose either “Use public data” or “Use my data”]
• Water Data Available
  • Water level: Auxiliary well locations with at least one water level measurement between 2018 and 2022. Note that this does not mean that a relevant water level measurement is available for the year and season of the EM survey. When no suitable water level measurements are available, our app force you to input a value of constant water table (default value is 30 m).
  • Water quality - fresh: Auxiliary well locations with at least one TDS measurement between 2010 and 2022 and the median value of the measurements is less than 1000 mg/L - Fresh.
  • Water quality - brackish: Auxiliary well locations with at least one TDS measurement between 2010 and 2022 and the median value of the measurements is greater than 1000 mg/L - Brackish.
• Water Level Options

  • Add contour data: Use water level contour data obtained from the SGMA data viewer in conjunction with water level measurements to improve interpolation of water level over the selected region.

  • Use constant water level: Always use a constant water level, irrespective of available water level data within the selected polygon. Once this option is activated there will be an extra space generated allowing you to input a constant water level (depth from the surface) as shown in Figure 8.

    

• START SIMULATION: launch a compute server to begin the process of creating recharge metric maps.

Note that by clicking an eye button you can either turn-on or turn-off the display of the data. An example display in the GIS layer is shown in Figure 9.

Within the selected region highlighted in Figure 7 and Figure 9 (i.e. Kaweah Subbasin), we found 1) three different EM surveys intersecting the region: two airborne EM (AEM) and one towed time-domain EM (tTEM) data sets); 2) 2092 wells containing sediment/rock type data; 3) 558 wells containing water level measurements; 4) 117 wells containing water quality measurements. Once you have selected a region of interest and selected the datasets you would like to work with, you can click the START SIMULATION button to launch a compute server for creating recharge metric maps for your region of interest!

Use my data or mix of my data and public data¶

When your EM data and/or sediment/rock type data are not available through our database, you can use your own data by uploading your data; this process was described in User account. Introducing your own data creates four additional possible combinations of EM and Sediment/rock type data:

1. My EM data + My Sediment/rock type data
2. My EM data + My Sediment/rock type data + Public Sediment/rock type data
3. My EM data + Public Sediment/rock type data
4. Public EM data + Public Sediment/rock type data
5. Public EM data + My Sediment/rock type data
6. Public EM data + My Sediment/rock type data + Public Sediment/rock type data

All four options assume that there are both EM data and Sediment/rock type data available. Let’s start with the first option. Your data data are accessible through a “Start with one of my data sets” located in the Simulation panel (#1 in Figure 1). Once you select a data set, the uploaded data will show up in the GIS layer as shown in Figure 10. In this case, we uploaded both EM data and Sediment/rock type data. For a local-scale application using tTEM data, it is possible that there are no water level measurements. In such a case, we force you to use an option, “Use constant water level”, as shown in Figure 10. Therefore, you need to provide your best guess about a water level. By clicking START SIMULATION button, you can launch a compute server.

The second option - My EM data + Public Sediment/rock type data - can be simply addressed by checking both “Use my dataset” and “Use public data” under “Sediment/Rock Type Data” section (Figure 11). Similarly, the third option - My EM data + Public Sediment/rock type data - can be addressed by just checking “Use public data” (Figure 12).

Fourth to sixth options commonly use Public EM data. Therefore, a region of interest is required to be drawn (or selected) by a user. An example GIS layer with a region of interest is shown in Figure 13. Similarly, all three options using public EM data can be addressed utilizing the “Sediment/Rock type Data” section.

Handle no sediment/rock type data¶

For a local-scale application, it is possible that there will be EM data but no sediment/rock type data available. In such a case acquiring the sediment/rock type data is highly recommended. However, if you want to proceed without sediment/rock type data, it is possible to proceed with our fastpath app. For instance, we created a region of interest covering a portion tTEM data as shown in Figure 14. There is no overlapping sediment/rock type data. Make sure you check “Use public data” to proceed in this case, otherwise the fastpath app will give you an error message. In addition, make sure to draw a region of interest tight enough to cover the EM data that you are interested in. If you draw a larger region of interest much greater than extent of the EM data, there is a possibility to include sediment/rock type data located far away from the EM data. This could raise an error in the later simulation step. So, the count of sediment/rock type wells should be zero for this case. You can then proceed with the rest of the workflow, and will need to manually enter information for the rock physics relationship (discussed in the Rock Physics Relationship section below).