Dirt roads, gravel roads - and it's hot hot hot

In the heat of the day (up to 35'C) I rode today, following this route (although it's not totally accurate because Google Maps doesn't let you map your travel on dirt roads - the route I rode did not include Hwy 30, but it did include the road one mile West of it, going North into A-town).

I took along 2 litres of water, which was probably not enough for this heat. That is, my sense the 1 litre per hour would be enough, will not be enough if it's 30+'C. This is a concern. It will be addressed ... somehow.