Stormwater Management in Michigan: Why LID? - Low Impact Development and Sustainable Stormwater Management - page 215

Figure 2.1 Water Cycle. Source : Stream Corridor Restoration: Principles. Processes, and
Practices, 10/98, Federal Interagency Stream Restoration Working Group (FISRWG).

Conventional land development changes the land surface and impacts the
water cycle (Figure 2.3). Altering one component of the water cycle invariably
causes changes in other elements of the cycle. Impervious surfaces, such as
roads, buildings, and parking areas, prevent rainfall from soaking into the
soil and significantly increase the amount of rainfall that runs off. Additionally,
research shows that soil compaction resulting from land development produces
far more runoff than the presettlement soil conditions. As natural vegetation
systems are removed, the amount of evapotranspiration decreases. As impervious
areas increase, runoff increases, and the amount of groundwater recharge

decreases.
These changes in the water cycle have a dramatic effect on our water
resources. As impervious and disturbed or compacted pervious surfaces increase
and runoff volumes increase, stream channels erode, substrate in the river