When rainwater is present in small amounts (e.g., the volume that can fall on your piece of property during a light rainfall) it is easy to handle and does a lot of good for our ecosystem. When rainwater is present in large amounts (e.g., running off large parking lots in subdivisions) it becomes fast-moving stormwater that is extremely costly to our environment and economy. Technically, the term stormwater refers to excess rainwater in undesirable places which requires a system of engineered pipes and channels that move large volumes of rainwater away from developments and transport it to a discharge system (often a lake or river or the ocean). This collected water has negative impacts on the environment, is very expensive and challenging to deal with, and can often result in flash flooding.
