Estimating the Volume of Saline Valley Basin using ASTER

TIR and an ASTER-derived DEM

Using the ENVI® Ecosystem by NV5 Geospatial

Imagery of Saline Valley, CA derived from the Advanced Spaceborne Thermal Emission and
Reflection Radiometer (ASTER) data was used for this theoretical analysis. The aim of this
experiment was to calculate both the potential volume of water that the valley basin would hold,
should it become filled, along with calculating the potential lake morphometry value.

Firstly, a region of interest (ROI) was created as a polygon over the basin area. This polygon
included only the basin, not the flow channels. The pixel size was found to be 90 meters from the
metadata. Length of the ROI was calculated using the measurement tool and found to be 599.9208
pixel. Its value became 53,992.872 when converted to meters. Area of the ROI was determined to
be:

The ROI was then loaded into the digital elevation model and
a transect was drawn from one end to the other (fig.1). The minimum depth was determined to be
350 m, while the maximum height was 1500 m. Net height was calculated as 1150 m. For the sake
of simplicity, the shape of the basin was simplified to be an inverted elliptic cone. The following
equation was used to estimate volume:

Where a is the major axis semidiameter, b is the minor axis semidiameter, and h is height. Both
diameters were measured using the measurement tool. Additionally, the lake morphometry was
calculated using the following equation:

Where s is the lake shoreline length and A is the area of the lake. Ds ranges between 1 and 2. This
indicates the irregularity of the lake’s shape, with 1 being a perfect circle. Simulated shoreline
distance was estimated using both the ROI and the measurement tool.

The resulting volume after solving for V was 325 cubic km of water. After comparing this value to other
lakes with similar surface areas, it was determined to be a reasonable estimation. Ds was calculated
as 1.54, which makes sense based on the lake’s irregular shape.