Map editor suggestions - Simulating drought, water flow and district radius

When creating a map, I think it will be useful to be able to simulate a drought. The reset function is no useful for that because it reset all the water. My idea is to be able to check which part of the map still has water left during drought, where trees are drying or not, how fast water is back after drought... By now, the only way to see it is to delete water source.
For water, it will be useful too to be able to check the water flow, to check if it is good enough for placing a water wheel.
Seeing the radius of the starting point can help to place it. Maybe with two options : "direct access radius" which show which part of the map is accessible whitout any constructions like platefrom or stairs (I often realized that I placed trees in an higher ground making it unreachable at starting) and "virtual access radius" which show how far the district covers the map (to see if we aren't placing things too far from it).