> For the complete documentation index, see [llms.txt](https://hydrosense.gitbook.io/ildas/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hydrosense.gitbook.io/ildas/technical/streamflow-calibration.md).

# Streamflow Calibration

We calibrated the ILDAS against daily observed streamflow for 18 major river basins in South Asia using Fully Parallelized Dynamically Dimensioned Search (FPDDS), Which leverages the high-performance computer (HPC) to get the optimal solution in fewer model runs than the traditional auto-calibration algorithm. FPDDS is based on the dynamically dimensioned search (DDS).​ We calibrated the ILDAS for seven different parameters as shown in the Table, which are mostly sensitive to surface runoff, sub-surface runoff, and soil moisture. The range and selection of the parameters are defined in the table. 

| Parameters | Total Parameters | Description\[units]                                                                                      | Range                |
| ---------- | ---------------- | -------------------------------------------------------------------------------------------------------- | -------------------- |
| MAXSMC     | 12               | Soil porosity \[No units]                                                                                | 0.1 – 0.7            |
| REFSMC     | 12               | Volumetric soil water content at field capacity \[No units]                                              | 0.05 – MAXSMC        |
| SATDK      | 12               | Soil hydraulic conductivity at saturation \[m/s]                                                         | 2×10-6 – 7×10-2      |
| BB         | 12               | Exponent in Brooks-Corey relation between volumetric soil moisture and soil matric potential \[No units] | 0.5 – 12             |
| REFDK      | 1                | Hydraulic conductivity at saturation for silt clay loamy soil \[m/s]                                     | 1.4×10-6 – 6.5 ×10-6 |
| REFKDT     | 1                | Related to surface infiltration factor \[No units]                                                       | 1 – 5                |
| Slope      | 9                | Linear scaling of “openness” of bottom drainage boundary \[No units]                                     | 0 – 1                |