To measure rainfall, we look at our rain gauge. A much better way is to look at the species of plants growing in our yard. Grass in a monoculture that has been mowed short on a regular basis and then irrigated does not infiltrate much of the water that falls on our yard. Short-rooted grasses are not conducive to infiltrating the water into the soil profile. If we get .5 inches on a lawn that looks well maintained, we may indeed infiltrate most of that depending on the soil moisture at the start of rain event. If we get 1 inch, we most likely will still only infiltrate .5 inches, the rest will runoff due to lack of root pores that go deep into the soil. If we allow multiple species such as clover, dandelions etc. grow we will have much more infiltration due to deeper root pores. Dandelions, aside from the telltale yellow flower and fuzzy seed head, are very beneficial to the health of the soil in our yard due to their deep tap root. Honeybees depend on dandelion blooms for their early season nectar supply. Bees love my yard because I supply them dandelions and clover from which they can collect nectar. The soil likes my yard too since I feed the soil microbes with multiple species with varying root depths. How much rain does our yard get? In reality much of that is up to us and how we maintain the plant species in our yard.
The author, Howard Miller, is the Outreach Coordinator for the Cheney Lake Watershed, Inc.