reorganize dask compute to avoid repeated load in wetland turbidity notebook

[uchchwhash]

Proposed changes

Invoke dask compute at the opportune moment. Saves about 9mins of runtime for me. Uses about 500MB more memory.

Checklist

(Replace [ ] with [x] to check off)

• Ensure that all code cells follow the PEP8 standard for code. The jupyterlab_code_formatter tool can be used to format code cells to a consistent style: select each code cell, then click Edit and then one of the Apply X Formatter options (YAPF or Black are recommended).
• Clear all outputs, run notebook from start to finish, and save the notebook in the state where all cells have been sequentially evaluated

[review-notebook-app]

Check out this pull request on 

See visual diffs & provide feedback on Jupyter Notebooks.

---

Powered by ReviewNB

[robbibt]

Awesome!