Types of bath prescribed by Parasara smruti equal to Ganga snanam - Taken from Tamil translation by Desikachariyar

1.  Applying ash over the body is called agneya snanam

2. Taking a dip in water - varunam

3. Getting purified by AapOhista mantram - Bhrahmam

4. Standing near the dust flying from cow's feet - Vayu

5. Getting drenched in rain falling when sun is visible - Divya snanam

Each of the above is considered euql to ganga snanam (dip in river ganga)