The dominant allele is expressed and the recessive allele is masked. This is an example of complete dominance. In heterozygous relationships where neither allele is dominant but both are completely expressed, the alleles are considered to be co-dominant. Co-dominance is exemplified in AB blood type inheritance.
swale (plural swales) 1  A low tract of moist or marshy land. 2  A long narrow and shallow trough between ridges on a beach, running parallel to the coastline. 3  A shallow troughlike depression that's created to carry water during rainstorms or snow melts; a drainage ditch.
Land on either side of the driveway may be pitched towards the driveway.This may lead too much water to the driveway area. One solution to this situation is to grade the land at the driveway edges away from the driveway. This then meets the land sloping towards the driveway so that a drainage swale can be created. A drainage swale is a pitched channel, typically located in lawn and not very noticeable, which takes water away to a lower location. My page on lawn drainage shows a picture of what a swale looks like and how it works. If you don't have the space for a swale, or it is just not a good driveway drainage solution, another alternative is to lay driveway drains at the driveway edge. Typically perforated pvc pipe is used. Corrugated pipe with slits in it is another type of drainage pipe that can be used.