New neighbourhoods and districts affect the environment by their very existence; they displace a previous natural state and disturb an existing balance.
If not building is not an option, then lessening the impact must guide the layout of new neighbourhoods. The degree to which their impact can be lessened depends on decisions about layout and building design.
Permeability The first and most critical alteration of a site is the change in the balance of the water cycle. Much of the original porous surface is covered with buildings and roads. Most vegetation that was part of the cycle is removed. Water runs away from the site causing pollution and erosion downstream while the site misses its water recharge. To emulate the original permeability and recharge, roads and buildings must be optimized to reduce their footprint. The fused grid optimizes the road pattern that serves a neighbourhood by eliminating unnecessary length and by reducing street width on lower classification streets.