Once you have dealt with groundwater and water flowing onto a site from elsewhere (see Building With Style, 12/95), you must tend to water originating on-site: rainwater and piped-in water. Why We Have a Problem Drainage problems are created by the act of building. The major impact of building is reduced absorption — my shorthand for the combination of absorption and evaporation. Buildings, paving, and lawn absorb much less moisture than naturally vegetated land. In addition, we often wish to correct the natural drainage to eliminate soggy places or to divert water from areas we want to use or build on. Step one is to deal with water coming off the roof. To Gutter or Not to Gutter Gutters are a
